Section 1 Design and Trend

**3**

**Chapter 1**

*Jozef Svetlík*

Industry 4.0 (I4.0) under way.

batches of individual products

**1. Introduction**

relationships.

connection

**Abstract**

Modularity of Production Systems

From the theoretical point of view, the chapter focuses on the unification of views on the living (constantly changing) structure of the construction of flexible production systems, including its cooperating devices. It contains currently defined and designated technical terms in the field of flexible production systems. From the theoretical point of view, the existing structures of the "multiprofessional manufacturing robotic center" are enhanced with new elements, which also contributes to innovation and expansion of their applications. These structural structures served as the basis for building sophisticated modular structures. Modularity is an integrating element directed at highly customizable manufacturing engineering structures. It fully complies with the requirements of manufacturing practice and demanding market, in the framework of fully implemented

**Keywords:** modularity, module, production systems, structure, platform

Modular manufacturing systems, as an integrated part of flexible manufacturing systems, deserve an unmistakable merit in today's rapidly changing manufacturing environment, characterized by developed competition in the global context and progressive changes in process technologies and in their structure according to market requirements. Such systems necessitate a rapid and factual integration of new technologies and new functions into both system and process

The Industry 4.0 (I4.0) trends and conditions and requirements require cyber

• A production capacity of production systems that is operatively adaptive to

• Fast integration of modern process technologies and new functions into

• Integrated production units with new service capabilities based on robust Industry Internet of Things (IIoT) data streams from individual work units and their accessibility for being processed from anywhere subject to Internet

existing production systems and their easy adaptation to dynamically changing

and flexible production-oriented approach, enabling to build the following:

market requirements, i.e., obtaining new, rapidly viable products

## **Chapter 1** Modularity of Production Systems

*Jozef Svetlík*

### **Abstract**

From the theoretical point of view, the chapter focuses on the unification of views on the living (constantly changing) structure of the construction of flexible production systems, including its cooperating devices. It contains currently defined and designated technical terms in the field of flexible production systems. From the theoretical point of view, the existing structures of the "multiprofessional manufacturing robotic center" are enhanced with new elements, which also contributes to innovation and expansion of their applications. These structural structures served as the basis for building sophisticated modular structures. Modularity is an integrating element directed at highly customizable manufacturing engineering structures. It fully complies with the requirements of manufacturing practice and demanding market, in the framework of fully implemented Industry 4.0 (I4.0) under way.

**Keywords:** modularity, module, production systems, structure, platform

### **1. Introduction**

Modular manufacturing systems, as an integrated part of flexible manufacturing systems, deserve an unmistakable merit in today's rapidly changing manufacturing environment, characterized by developed competition in the global context and progressive changes in process technologies and in their structure according to market requirements. Such systems necessitate a rapid and factual integration of new technologies and new functions into both system and process relationships.

The Industry 4.0 (I4.0) trends and conditions and requirements require cyber and flexible production-oriented approach, enabling to build the following:


#### **2. Flexible manufacturing systems**

Flexible manufacturing systems (FMS) enable flexible production of a product group in a single production system. Using modular principles, flexible manufacturing, which is the fundamental concept of cyber production systems, has recently become one of the major systems of production management. These arrangements are (and there are several of them) theoretically and methodically based on the search for a mathematically modeled component production center relationship that would guarantee different types of parts produced with a small number of pieces in the batch. The modular structure of the production systems enables links between machines, saving production time and space. The operation of the machines is synchronized via data stream, and the material flow is optimized (moving parts between machines is at an optimal distance). FMS utilizes many advantages of other types of production structures (**Table 1**) [1].

The dynamic development of computers, information science, data processing, control and managing systems, optical systems, drives, and materials, that is taking place in short cycles, significantly affects the growth rate (obsolescence) of the technical level of the systems in question. An efficient manufacturing system can become inefficient in a short time. In addition, the current customer-oriented market, as well as the environmental, energy and material issues, results in accelerated launch of new products. The adaptability of established manufacturing systems to new products may not have sufficient technical availability, and the introduction


**5**

**Figure 1.**

*An unconventional view of the "flexibility" concept.*

*Modularity of Production Systems*

and maintenance activities).

workpiece)

development (**Figure 1**).

rability, two areas need to be focused on:

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

of new technically available systems may take too long a time from the production

For these reasons, it is necessary to pay constant attention to flexible, modular, and reconfigurable production systems and consequently to improve them systematically and technically and adapt them to the needs of current production processes

Generally, the best-selling article (or article with the highest investment value) of production technology are the CNC machine tools. Prof. Marek writes in [3]

Forecasts focused on the position of modular technologies in the twenty-first century confirm their important place in both fully automated production plants (both engineering and nonengineering areas) and in non-production areas (service

Thus, the modularity and reconfigurability in terms of where the development is heading have the potential for further development in the future. Design of reliable (universal) modules or of the building nodes with a wider applicability is, and will always be, topical. This desired property can be achieved through experience, selection of suitable elements, and reliable design. In terms of reliability and reconfigu-

• Design of machine tools (machine reconfiguration to another type of

• Production (technology reconfiguration to another type of workpiece)

The possibilities and tools for increasing the performance of production machines in multifunction machinery are associated with the developed ability to fully perform several types of machining, e.g., turning and milling at the same time

The concept of flexibility is also related to reconfigurability and structurelability. Flexibility can also be seen from the point of view of design and manufacturing

availability point of view (machine tools approximately 2 years).

about the factors influencing the development of machine tools.

or to the needs of current engineering production [1, 2].

#### **Table 1.** *Overview of basic production system structures.*

#### *Modularity of Production Systems DOI: http://dx.doi.org/10.5772/intechopen.90844*

of new technically available systems may take too long a time from the production availability point of view (machine tools approximately 2 years).

For these reasons, it is necessary to pay constant attention to flexible, modular, and reconfigurable production systems and consequently to improve them systematically and technically and adapt them to the needs of current production processes or to the needs of current engineering production [1, 2].

Generally, the best-selling article (or article with the highest investment value) of production technology are the CNC machine tools. Prof. Marek writes in [3] about the factors influencing the development of machine tools.

Forecasts focused on the position of modular technologies in the twenty-first century confirm their important place in both fully automated production plants (both engineering and nonengineering areas) and in non-production areas (service and maintenance activities).

Thus, the modularity and reconfigurability in terms of where the development is heading have the potential for further development in the future. Design of reliable (universal) modules or of the building nodes with a wider applicability is, and will always be, topical. This desired property can be achieved through experience, selection of suitable elements, and reliable design. In terms of reliability and reconfigurability, two areas need to be focused on:


The concept of flexibility is also related to reconfigurability and structurelability. Flexibility can also be seen from the point of view of design and manufacturing development (**Figure 1**).

The possibilities and tools for increasing the performance of production machines in multifunction machinery are associated with the developed ability to fully perform several types of machining, e.g., turning and milling at the same time

#### **Figure 1.**

*An unconventional view of the "flexibility" concept.*

or milling and grinding, etc. Reducing the number of machine tools for the production of one component, less handling, shortening the lead times, minimizing the recurrence of workpiece clamping, maximizing the concurrence of operations, as well as the development of machine components and machine concepts for maximum machine multifunctionality contribute to:


Unification of parts and components is implemented in order to minimize diversity of the components used, while maintaining very good static and dynamic properties of the machines and, at the same time:


#### **2.1 New approach to production systems classification**

In the area of production systems, a number of terms are used with broader interpretation. This situation is related to approaches to and perspectives on this issue. A proposal for their general unification and effective classification is given in **Figure 2**.

Various definitions of production systems from different points of view are cited in various literature sources [1]. This has led to the need to harmonize these formulations so that they provide the most precise definitions, taking into account current knowledge in this area:

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*Modularity of Production Systems*

working functions).

goal (def. Inspired by [5]).

**2.2 Modular production centers**

milling, drilling, etc.)

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intervals, to produce small quantities efficiently.

*Flexible production system*—a functional grouping of production facilities linked by material flow and information network, enabling the use of flexible change in production facilities due to the introduction of new products in relatively short time

*Structural production system*—flexible set of compatible elements (technological and positioning units, supporting frame, cooling system, etc.) and their mutual links, which can be expanded with new elements to change the system parameters. *Modular system*—flexible set of unified modules (module—separately functional unit) in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement into higher functional unit (meeting required parameters and

*Reconfigurable system*—a modular system with the possibility to change the arrangement of its own modules (in terms of structure, system, concept, kinemat-

*Self-reconfigurable system*—a reconfigurable system capable of independently reconfiguring its own modules (in terms of structure, system, concept, kinematics,

*Metamorphic system*—a closed self-reconfigurable system to create an innovated

*Fractal system*—an open, self-reconfigurable system consisting of proactively behaving elements—fractals (their structure is recurrent) which pursue a common

In the category of manufacturing technology, machining centers (MC) are defined as manufacturing machines designated for complex components machining with defined characteristics. According to the number and type of technological

• Multipurpose (multi-operation)—machines with a predominant technological operation (e.g., turning), i.e., they mostly enable one type of technology

• Multiprofessional (multiprofessional productions center (MPC))—machines on which various technological operations can be performed (e.g., turning,

Production centers are conceptually built on the principles of modular systems or as modular single-purpose machines. In terms of design and structure, they are assembled from technological, handling, and auxiliary units (mechanical, electromechanical, hydraulic, pneumatic) integrated through a supporting element (frame) into one functional and structural unit. The highest integration of production centers is based on the automation of technological and handling operations. These are multiprofessional machine tools designed for complex machining of parts on one machine and, if possible, requiring one clamping. To machine a workpiece requiring one clamping, its rotation must be ensured (e.g., in the X-Y plane) and so must be its tilting. The machining centers are equipped with a tool magazine automatically replaced by a mechanical hand. Some tools feature their own drive, which makes drilling off the workpiece axis or its milling possible, especially on lathes. Machining centers represent the basic AVS production machines. They are mainly used in piece and small batch production. Machining centers are characterized by a high concentration of operations. The machining is often carried out with the component clamped only once. They are mostly equipped with tool magazines

ics, etc.) in order to create an innovated system with innovated properties.

etc.) to create an innovated system with innovated features.

operations performed, machining centers are divided into:

system with innovated features (def. Inspired by [4]).

**Figure 2.** *Open proposal for production systems classification.*

#### *Modularity of Production Systems DOI: http://dx.doi.org/10.5772/intechopen.90844*

*Flexible production system*—a functional grouping of production facilities linked by material flow and information network, enabling the use of flexible change in production facilities due to the introduction of new products in relatively short time intervals, to produce small quantities efficiently.

*Structural production system*—flexible set of compatible elements (technological and positioning units, supporting frame, cooling system, etc.) and their mutual links, which can be expanded with new elements to change the system parameters.

*Modular system*—flexible set of unified modules (module—separately functional unit) in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement into higher functional unit (meeting required parameters and working functions).

*Reconfigurable system*—a modular system with the possibility to change the arrangement of its own modules (in terms of structure, system, concept, kinematics, etc.) in order to create an innovated system with innovated properties.

*Self-reconfigurable system*—a reconfigurable system capable of independently reconfiguring its own modules (in terms of structure, system, concept, kinematics, etc.) to create an innovated system with innovated features.

*Metamorphic system*—a closed self-reconfigurable system to create an innovated system with innovated features (def. Inspired by [4]).

*Fractal system*—an open, self-reconfigurable system consisting of proactively behaving elements—fractals (their structure is recurrent) which pursue a common goal (def. Inspired by [5]).

#### **2.2 Modular production centers**

In the category of manufacturing technology, machining centers (MC) are defined as manufacturing machines designated for complex components machining with defined characteristics. According to the number and type of technological operations performed, machining centers are divided into:


Production centers are conceptually built on the principles of modular systems or as modular single-purpose machines. In terms of design and structure, they are assembled from technological, handling, and auxiliary units (mechanical, electromechanical, hydraulic, pneumatic) integrated through a supporting element (frame) into one functional and structural unit. The highest integration of production centers is based on the automation of technological and handling operations. These are multiprofessional machine tools designed for complex machining of parts on one machine and, if possible, requiring one clamping. To machine a workpiece requiring one clamping, its rotation must be ensured (e.g., in the X-Y plane) and so must be its tilting. The machining centers are equipped with a tool magazine automatically replaced by a mechanical hand. Some tools feature their own drive, which makes drilling off the workpiece axis or its milling possible, especially on lathes. Machining centers represent the basic AVS production machines. They are mainly used in piece and small batch production. Machining centers are characterized by a high concentration of operations. The machining is often carried out with the component clamped only once. They are mostly equipped with tool magazines

exchanged automatically as needed. The most common main feature of machining centers is the largest machined part dimension.

#### **2.3 MPC and MPRC definitions**

*MPC***—**a set of working units (technological, handling, conveyors) integrated into one unit (frame), characterized by flexibly reprogrammable common control system, mostly with human operation. The nature and structure of the MPC construction classifies it under the group of modular reconfigurable production systems [1].

*MPRC*—a fully automated set of autonomous modules, integrated into a single unit (frame), with a common, flexibly reprogrammable control and the use of robotic devices performing the function of handling and technological work units [1, 6]. The nature and structure of the MPRC construction classifies it under the modular reconfigurable production systems.

MPRC characteristic features:


Unlike the type-specific structures of automated production systems, the MPRC provides a fully automated multiprofessional technology cycle designed for complete workpiece production and has a simpler (fewer number of elements/ modules) structure, less space requirements, and more integration of technological (handling) control functions.

#### **3. Modularity and flexibility of production systems**

The technical system is described by terminology which determines the procedures, tools, and methods for its description, understanding, and interpretation.

*System*—a purposefully defined set of at least two elements and a set of links between them, both sets specifying the properties of the whole. The links can be understood in terms of their physical or logical relationship. From the technical point of view, a system may be mechanical or functional. Each system is made up of individual elements. An important feature of the system is that its elements in relation to each other can work together as a whole. The manifestation and properties of the system represent more than a simple sum of the properties of its elements. The system as a whole may exhibit behavior that is missing in the behavior of its elements.

*Subsystem*—part of the system, which creates a relatively closed, separate functional unit within the system. As a rule, it consists of two components: elements and links. The links between elements are often called interfaces. The subsystems cooperate with each other in a system function algorithm. The subsystems can be viewed independently.

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*Modularity of Production Systems*

the basic system function).

**Figure 3.**

Element designation:

module Uj to Ui).

"p" passive.

MTS—Modular technical system.

*Structure diagram of the general modular technical system.*

there is no possibility of linking the modules):

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

*Module*—a basic building block of modular structure, which is a separate unit structurally, functionally, and in terms of design (a materialized implementation of

*Modular system (MS)*—complete set of modules (unified units, functional nodes, modular blocks, etc.) in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement of a higher functional unit, featuring

*Modular system structure—*a set of modules and their mutual links and configurations. Change in the interconnection/arrangement of modules results in the emergence of new delimited functional and kinematic system configurations.

Yi—Module output parameters (properties, operating functions), "a" active,

The mutual linking of AM modules is based on their arrangement in the techni-

, or xij = 0, if

cal structure of the system ψ. The possibilities of connecting the AMi and AMj modules are described by the matrix of the *MTSf* system structure (matrix of the type n × n, where n is the number of modules AM = {AM1, AM2, ...,} AMn forming the MTS, while the set of binary links x = {x11, x12, ...,xnn} on the set AM expresses

MT Sf = [xij] (1)

xij = 1, if there is a possibility of creating a link between AMi and AMj

AMi—Unified modular unit (functional node, modular block, etc.) Ui—Mutual links (compatibility of ij module Ui to Uj, or of the ji

*Modularity*—a feature of a technical system that allows its decomposition into a

required parameters and working functions (**Figure 3**) [1].

group of autonomous, loosely coupled elements—modules.

X i—Module input parameters (set requirements).

**3.1 Functionality of the modular technical system structure**

#### **Figure 3.**

*Structure diagram of the general modular technical system.*

*Module*—a basic building block of modular structure, which is a separate unit structurally, functionally, and in terms of design (a materialized implementation of the basic system function).

*Modular system (MS)*—complete set of modules (unified units, functional nodes, modular blocks, etc.) in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement of a higher functional unit, featuring required parameters and working functions (**Figure 3**) [1].

*Modularity*—a feature of a technical system that allows its decomposition into a group of autonomous, loosely coupled elements—modules.

*Modular system structure—*a set of modules and their mutual links and configurations. Change in the interconnection/arrangement of modules results in the emergence of new delimited functional and kinematic system configurations.

Element designation:

MTS—Modular technical system.

AMi—Unified modular unit (functional node, modular block, etc.) Ui—Mutual links (compatibility of ij module Ui to Uj, or of the ji module Uj to Ui).

X i—Module input parameters (set requirements).

Yi—Module output parameters (properties, operating functions), "a" active, "p" passive.

#### **3.1 Functionality of the modular technical system structure**

The mutual linking of AM modules is based on their arrangement in the technical structure of the system ψ. The possibilities of connecting the AMi and AMj modules are described by the matrix of the *MTSf* system structure (matrix of the type n × n, where n is the number of modules AM = {AM1, AM2, ...,} AMn forming the MTS, while the set of binary links x = {x11, x12, ...,xnn} on the set AM expresses xij = 1, if there is a possibility of creating a link between AMi and AMj , or xij = 0, if there is no possibility of linking the modules):

$$\mathbf{MTS}\_{\mathbf{f}} = \begin{bmatrix} \mathbf{x}\_{ij} \end{bmatrix} \tag{1}$$

#### **3.2 Assembly of modular technical system structure**

By combining the modules AM ={AM1, AM2,..., AMn,}, the MTS can be assembled with none or several degrees of freedom of motion. MTS motion options with respect to a defined coordinate system can be analyzed from the *MTSpb* motion matrix (n x n matrix type, where n is the number of modules AM = {AM1, AM2,...,AMn,} forming the MTS, where bij = 0 if there is no connection between AMi and AMj , or bij = 0 if the modules are combined to form a unit without motion options, or bij = 1 if the modules are combined to form a unit with one degree of freedom of motion, bij = 2 with two degrees, etc.).

$$\mathbf{MTS}\_{\rm pb} = \begin{bmatrix} \mathbf{b}\_{\rm ij} \end{bmatrix} \tag{2}$$

The AM module, a critical element of the MTS ψ structure, is defined as a unified unit, separate structurally, functionally, and in terms of design, composed of elements, elements E (e.g., mechanical module, servo drive, possibly also source, control, and communication module), with a specified level of function integration (main, secondary, auxiliary) and intelligence (control and information, control and decision function), capable of connecting with other modules mechanically, and in terms of control, creating functionally higher units in the technical structure of the system ψ:

$$\mathbf{MTS}\_{\Psi} \simeq \sum\_{\mathbf{j=1}}^{\mathbf{a}} \mathbf{AM}\_{\mathbf{j}} \simeq \sum\_{\mathbf{j=1}}^{\mathbf{a}} \sum\_{\mathbf{i}=1}^{\mathbf{c}\_{\mathbf{j}}} \mathbf{E}\_{\mathbf{i},\mathbf{j}} \tag{3}$$

AMr + 1 inputs are X parameters of MTS task transformed to Xr + 1 parameters of Xr + 1 partial task and Urr + 1 compatibility parameters transformed as interaction of directly linked downstream AMr module in MTS structure. Outputs from the AMr + 1 module are output parameters Yr + 1u and Yr + 1p of the AMr + 1 module representing the performance of a partial task of the module transformed into output parameters Y of the MTS robot and the Ur + 1r compatibility parameters, by which the AMr + 1 module directly affects the subsequently linked module AMr to the MTS structure (**Figure 4**).

$$\mathbf{X} = \mathbf{f}(\mathbf{X}\_1, \dots, \mathbf{X}\_n, \dots, \mathbf{X}\_r, \dots, \mathbf{X}\_{r+1}) \tag{4}$$

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**Figure 5.**

*An illustration of the modular systems' specificities.*

*Modularity of Production Systems*

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

their importance to the MTS functions:

MTSΨ = ∑

**3.4 Concepts of flexible technical systems**

**3.3 Modular system properties**

features (**Figure 5**):

*AM modules*—Depending on their importance for the MTS functions, they can be classified as the main active ones (ensure the main function, number l of total number m + l + a modules, e.g., motion modules), the secondary active/passive ones (ensure secondary support function, remaining number a out of total number m + l + a modules, e.g., a coupler module), and the auxiliary passive ones (ensure the auxiliary function, remaining number a out of the total number of m + l + a modules, e.g., a carrier). MTS can be described by an AM module set according to

> j−1 1

 AMj + ∑ j−1+1 m

Unlike the conventional systems, modular systems have the following specific

According to the breakdown in **Figure 2**, the flexible technical systems include modular and structural systems (STS). The difference between these systems is mainly in the autonomy or the sophistication of basic building elements.

The concept of MTS design is to create a complete set of modules (unified units, functional nodes, modular blocks, etc.) and their links in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement into a higher functional unit, meeting the required parameters and working functions.

AMj + ∑

j−m+1 a

AM j (6)

$$\mathbf{Y} = \mathbf{f}\{\mathbf{Y}\_{\text{1pu}}, \dots, \mathbf{Y}\_{\text{nup}}, \dots, \mathbf{Y}\_{\text{ru}}, \dots, \mathbf{Y}\_{\text{r} \ast \text{ 1u}}, \dots, \mathbf{Y}\_{\text{1p}}, \dots, \mathbf{Y}\_{\text{np}}, \dots, \mathbf{Y}\_{\text{r} \ast \text{ 1p}}\}\tag{5}$$

**Figure 4.** *Structure diagram of the general autonomous module (AM).*

*Modularity of Production Systems DOI: http://dx.doi.org/10.5772/intechopen.90844*

*AM modules*—Depending on their importance for the MTS functions, they can be classified as the main active ones (ensure the main function, number l of total number m + l + a modules, e.g., motion modules), the secondary active/passive ones (ensure secondary support function, remaining number a out of total number m + l + a modules, e.g., a coupler module), and the auxiliary passive ones (ensure the auxiliary function, remaining number a out of the total number of m + l + a modules, e.g., a carrier). MTS can be described by an AM module set according to their importance to the MTS functions:

$$\mathbf{MTS}\_{\Psi} = \sum\_{j=1}^{4} \mathbf{AM}\_{j} + \sum\_{j=1\star 1}^{4} \mathbf{AM}\_{j} + \sum\_{j=\star 1}^{4} \mathbf{AM} \, \mathbf{j} \tag{6}$$

#### **3.3 Modular system properties**

Unlike the conventional systems, modular systems have the following specific features (**Figure 5**):

#### **3.4 Concepts of flexible technical systems**

According to the breakdown in **Figure 2**, the flexible technical systems include modular and structural systems (STS). The difference between these systems is mainly in the autonomy or the sophistication of basic building elements.

The concept of MTS design is to create a complete set of modules (unified units, functional nodes, modular blocks, etc.) and their links in functionally logical (in terms of structure, system, concept, kinematics, etc.) arrangement into a higher functional unit, meeting the required parameters and working functions.

**Figure 5.** *An illustration of the modular systems' specificities.*

*Implementing interconnections***—**arrangement of the assembly of elements and a change of the same:


*Concept 1—Structural systems with fixed links,* such as structural gripper heads by "SCHUNK" (**Figure 6**), STS assembly from a defined number and types of standardized elements (motion units, motion lines, building blocks, unified nodes, etc.), with the possibility of its mechanical conversion outside of operation into new functional and operational STS configurations [7].

*Concept 2—Structural systems with variable links,* e.g., a turret with multi-spindle heads from Riello Sistemi [8] (**Figure 7**), **STS** assembly from a defined number and types of elements (spindle heads, gripping units, structural blocks, unified nodes, etc.), with the possibility of its mechanical conversion in course of its operation into new functional and operational **STS** configurations.

*Concept 3—Reconfigurable modular systems with fixed links,* e.g., modules by Riello Sistemi (**Figure 8**), **MTS** assembly from a defined number and types of **AM** autonomous modules (motion units, motion modules, modular blocks, unified nodes, etc.), with the possibility of its mechanical conversion outside operation into new functional and operational **MTS** configurations.

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**Figure 8.**

**Figure 7.**

*from Riello Sistemi.*

*Concept 4—Self-configurable modular systems with variable links,* e.g., modules from Riello Sistemi [8] (**Figure 9**) **MTS** assembly from variable number and types of autonomous **AM** modules (motion units, motion modules, modular blocks, unified nodes, etc.), with the possibility of self-conversion in course of the operation

*Concept 2, reconfiguration by adding new elements to the assembly (in production technology, spindle heads)* 

into new functional and operational **MTS** configurations.

*Concept 3, reconfigurable modules by Riello Sistemi [8].*

*Modularity of Production Systems*

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

**Figure 6.** *STS rebuilding concept 1 with fixed links by SCHUNK.*

#### **Figure 7.**

*Concept 2, reconfiguration by adding new elements to the assembly (in production technology, spindle heads) from Riello Sistemi.*

**Figure 8.** *Concept 3, reconfigurable modules by Riello Sistemi [8].*

*Concept 4—Self-configurable modular systems with variable links,* e.g., modules from Riello Sistemi [8] (**Figure 9**) **MTS** assembly from variable number and types of autonomous **AM** modules (motion units, motion modules, modular blocks, unified nodes, etc.), with the possibility of self-conversion in course of the operation into new functional and operational **MTS** configurations.

**Figure 9.** *Concept 4, self-reconfigurable module sets by Riello Sistemi.*

#### **3.5 Modularity of technical systems**

A particular MTS architecture made up of AM modules should meet the technical requirements of the application, quality, durability, and safety.

In the MTS system, the AMs are interchangeable—links with other parts of the MTS system are ensured by standard (or special purpose) connectors (interfaces).

AM module features—type and shape of the AMi module depend on its functionality in the MTS system configuration and parameterization of the resulting requirements (features):


*The building module architecture* is based on the need to appropriately group suitable modules into an MTS architecture that is recurrent for certain types of applications in the form of a structural base.

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Modules grouped in the MTS architecture (**Figure 10**):

platform (MP)) assemblies, e.g., MTS01.

*Grouping of the modules into a platform in the general MTS structure.*

(MM)), e.g., M5.

**Figure 10.**

(MS)), e.g., M4.

the MTS assemblies.

structure) (**Figure 11**).

(functionality).

can assume a value of *kM* ∈ 〈0, 1〉 [9].

• A *platform* is a set of modules used in multiple complete MTS (modules of

• A set of modules involved in multiple MTS sets (multimachine modules

• A set of modules involved in only one robot assembly (singlemachine modules

The degree of utilization of the unified building modules in the individual MTS design kit expresses the "degree of modularity." In general, the degree of modularity

It is recommended the structure of the MTS assemblies under consideration be compiled into the so-called modular system maps—a clear display of structures of individual assemblies and display of usage of individual building module options in

**3.6 Modularity of production technology, features, and characteristics**

*Assessing modularity*—feasible from several points of view. For practical needs of design and operation of production systems, it is appropriate and sufficient to divide modularity into basic groups (in relation to the designed

*Functional modularity*—linked to the main MTS functions and features (mainly operational). Changing the AM module will change the MTS function *Modularity of Production Systems DOI: http://dx.doi.org/10.5772/intechopen.90844*

**Figure 10.**

*Grouping of the modules into a platform in the general MTS structure.*

Modules grouped in the MTS architecture (**Figure 10**):


The degree of utilization of the unified building modules in the individual MTS design kit expresses the "degree of modularity." In general, the degree of modularity can assume a value of *kM* ∈ 〈0, 1〉 [9].

It is recommended the structure of the MTS assemblies under consideration be compiled into the so-called modular system maps—a clear display of structures of individual assemblies and display of usage of individual building module options in the MTS assemblies.

#### **3.6 Modularity of production technology, features, and characteristics**

*Assessing modularity*—feasible from several points of view. For practical needs of design and operation of production systems, it is appropriate and sufficient to divide modularity into basic groups (in relation to the designed structure) (**Figure 11**).

*Functional modularity*—linked to the main MTS functions and features (mainly operational). Changing the AM module will change the MTS function (functionality).

**Figure 11.** *Modularity breakdown.*

*Type-dimensional modularity*—characterizes the MTS design, its flexible transformation view of another MTS-type series. By changing the AM module, the functional dimensions/performance parameters of the MTS design are changed.

The *AM-type series* (grading of AM parameters or specifying the AM type) is done by distinguishing the parameters as follows:


*Component modularity*—characterizes the MTS design in terms of production, maintenance, and service. Changing the AM module does not change the functional dimensions or performance parameters of the MTS design. Such AM module replacement/application makes sense for streamlining the production, service, and maintenance.

**AM** elements**—components** of one type are physically similar. For this reason, once the conditions are met, the principles of similarity theory [1] can be applied.

**Figure 12** shows a dual biaxial modular manipulator designed for varying degrees of load. If the modular assembly is subjected to maximum loads, it is necessary to reduce the motion dynamics to the recommended level or to choose a dimensional range of higher type for the construction of the handling equipment (**Figure 13**) [10].

#### **3.7 Modular production machines**

Currently, modular production machines represent advanced machine systems designed on the basis of a mechatronic approach to their design, with the predominant concept of their construction being a three-dimensional and functional modularity structurally built on fixed links.

Conceptually, these structures obey the principles of functional and type and dimension-specific modularity structurally built on fixed links.

**17**

**3.8 Modular robotic systems**

*Modularity of Production Systems*

**Figure 12.**

**Figure 13.**

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

*Güdel ZP-type biaxial portal linear motion modules.*

An example of functional modularity is the IMG industry concept (**Figure 14**). Machining centers, production cells, and transfer lines of varying degrees of com-

These two concepts are now strongly prevalent in the development of modular manufacturing technology. A feature of the application of these two concepts in the development of this technique is also their overlap in case of a certain degree of fuzziness of their boundaries or their combination. This direction is particularly pronounced in modular systems enabling the assembly of higher functional units such as machining centers, multiprofessional centers, and production cells.

Industrial robots and manipulators are implemented as modular systems mainly

due to the requirements of flexible automated production systems [4, 11, 12]. From a number of current designs (EPSON, SCHUNK, YAMAHA, KUKA, MOTOMAN, etc.), the solution by SCHUNK will be introduced (**Figure 15**), the

plexity can be built from the presented base of modules and platforms.

*Güdel type and size-specific linear portal modules of the ZP type.*

#### **Figure 12.**

*Güdel ZP-type biaxial portal linear motion modules.*

#### **Figure 13.**

*Güdel type and size-specific linear portal modules of the ZP type.*

An example of functional modularity is the IMG industry concept (**Figure 14**). Machining centers, production cells, and transfer lines of varying degrees of complexity can be built from the presented base of modules and platforms.

These two concepts are now strongly prevalent in the development of modular manufacturing technology. A feature of the application of these two concepts in the development of this technique is also their overlap in case of a certain degree of fuzziness of their boundaries or their combination. This direction is particularly pronounced in modular systems enabling the assembly of higher functional units such as machining centers, multiprofessional centers, and production cells.

#### **3.8 Modular robotic systems**

Industrial robots and manipulators are implemented as modular systems mainly due to the requirements of flexible automated production systems [4, 11, 12].

From a number of current designs (EPSON, SCHUNK, YAMAHA, KUKA, MOTOMAN, etc.), the solution by SCHUNK will be introduced (**Figure 15**), the

**Figure 14.** *Modular concept of EMAG production machines [13].*

**Figure 15.**

*Modular robot SCHUNK [7]. one- to three-finger gripping effector; 2, rotary module; 3, mechanical interface.*

concept of which corresponds to the principles of functional modularity. The presented robot has 7 degrees of freedom when the required number of rotary motion modules can be linked in the series kinematic chain as required. In the design concept, rotary modules are arranged alternately perpendicular to each other, and linked modules are using complex shape interface, which is subject to demanding

**19**

**Figure 17.**

**Figure 16.**

*Basic concept of universal rotational module (URM).*

*Modularity of Production Systems*

**rotation (URM)**

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

requirements of stiffness and low weight (a lighter metal material with sufficient strength). This concept is based on the complex structure of the modular system and the links of its elements. The advantage of this design is high flexibility and

SCHUNK solution (**Figure 15**) can be improved with an innovative custom solution. The presented system of rotary modules called universal rotary module (URM) (**Figure 16**) has any number of degrees of freedom, within the rigidity, load-bearing, and precision characteristics of course. They can be connected to the required number of degrees of freedom (DOF) in the kinematic chain as required. The design concept is changed from the SCHUNK solution so that the rotary

*Basic concept of standalone URM module and section of its structure. 1, reductor; 2, accumulators;* 

*3, servomotor; 4, body; 5, interface; 6, connection panel; 7, coil winding; 8, rotational connection; 9, next URM.*

accommodation of a wide range of requirements of real applications.

**4. Design of own universal rotary module with unlimited** 

*Modularity of Production Systems DOI: http://dx.doi.org/10.5772/intechopen.90844*

requirements of stiffness and low weight (a lighter metal material with sufficient strength). This concept is based on the complex structure of the modular system and the links of its elements. The advantage of this design is high flexibility and accommodation of a wide range of requirements of real applications.

#### **4. Design of own universal rotary module with unlimited rotation (URM)**

SCHUNK solution (**Figure 15**) can be improved with an innovative custom solution. The presented system of rotary modules called universal rotary module (URM) (**Figure 16**) has any number of degrees of freedom, within the rigidity, load-bearing, and precision characteristics of course. They can be connected to the required number of degrees of freedom (DOF) in the kinematic chain as required. The design concept is changed from the SCHUNK solution so that the rotary

**Figure 16.** *Basic concept of universal rotational module (URM).*

#### **Figure 17.**

*Basic concept of standalone URM module and section of its structure. 1, reductor; 2, accumulators; 3, servomotor; 4, body; 5, interface; 6, connection panel; 7, coil winding; 8, rotational connection; 9, next URM.*

modules are arranged at different angles in the range of 15 to 90° and not perpendicular to each other.

A simple interface is used to connect the modules (**Figure 17**, item 5) which by its curvature determine the extent and reach of the working space of the kinematic structure, which are subject to tough requirements of stiffness and low weight (material of lighter metal with sufficient strength). This concept is based on the complex structure of the modular system and its constraints. The advantage of the solution is high flexibility and coverage of a wide range of requirements of real applications.

Depending on the number of modules involved, a modular manipulator can be created with a working space of different ranges, positions, and shapes (**Figure 18**). The number of modules also determines the number of degrees of freedom of the manipulator. The design and construction of the URM allows the modules themselves to be modified so that their curvature angle may be different from the basic 45°, 90°, and the like. Subsequently, it is possible to assemble modified robot structures. Extension modules can be inserted between the modules to increase the reach of the manipulator arm while maintaining sufficient rigidity of the kinematic chain. All modifications to the mechanical part must be taken into account in the setup and programming of the robot control system.

The main benefits of designing URM-based modular structures are a pair of conveniences:


**21**

**Figure 20.**

*(right) with basic dimensions.*

**Figure 19.**

*Modularity of Production Systems*

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

**4.1 Design of URM prototype for robotic systems**

*Manipulator with 6 DOF of movement made of URM 01 modules.*

The URM is developed by one department from Manufacturing Machinery, Faculty of Mechanical Engineering, Technical University of Košice. The result of this solution is a modular system that allows us to assemble modular robots, assembled from identical or type-identical URM01 with unlimited rotational motion. Machines and equipment constructed from these modules are designed to ensure the best possible working range and also to achieve the desired space in the work area (**Figure 19**).

*The first version of the URM01 prototype (left) versus the second version of the proposed URM 02 prototype* 

**Figure 18.** *Examples of reach of a modular assembly made of URM with 6 DOF.*

#### **4.1 Design of URM prototype for robotic systems**

The URM is developed by one department from Manufacturing Machinery, Faculty of Mechanical Engineering, Technical University of Košice. The result of this solution is a modular system that allows us to assemble modular robots, assembled from identical or type-identical URM01 with unlimited rotational motion. Machines and equipment constructed from these modules are designed to ensure the best possible working range and also to achieve the desired space in the work area (**Figure 19**).

**Figure 19.** *Manipulator with 6 DOF of movement made of URM 01 modules.*

#### **Figure 20.**

*The first version of the URM01 prototype (left) versus the second version of the proposed URM 02 prototype (right) with basic dimensions.*

The main parameter of URM01 is the angle of curvature of the interconnectors. Since this is a homogeneous structure, the curvature of each manipulator module will be the same. A homogeneous structure with 5 DOF of movement was subjected to a series of simulation tests with different angles of curvature of the couplers. In the individual curves of the couplers, structures with interesting shapes are formed. The analysis of the working space of the individual series structures with different angles of curvature of the couplers has brought to light the fact that the more the angle of curvature of the coupler increases, the more the working space of the individual serial structures increases.

The best working space range in all axes has a series structure with 90° curvature of the coupler. This is similar to the standard solutions of SCHUNK, KUKA, etc. In our case, given the curvature of the spacer, it is necessary to consider the possibility of collision with the own modules. This problem can be addressed with the correct control algorithm or software-embedded software limit switches that alert the control system to the limit position of the axis and consequently prevent access beyond that limit.

The prototype URM02, which is conceptually based on the original first variant of URM01, is currently being completed (**Figure 20**). The development of the second-generation URM02 has brought many improvements and possibilities that its predecessor did not contain. Development has taken URM02 to a higher level, making it easier and more efficient to use it in industrial applications. As with any development, the aim was to achieve the best possible results based on the stated objectives and rules of previous research and testing.

#### **5. Conclusions**

Benefits of applying modularity to production systems:


**23**

**Author details**

Jozef Svetlík

*Modularity of Production Systems*

**Acknowledgements**

*DOI: http://dx.doi.org/10.5772/intechopen.90844*

**Appendices and Nomenclature**

MC machining center

kM degree of modularity DOF degrees of freedom

FMS flexible manufacturing system RMS reconfigurable production system

MPC multiprofessional productions center

Eij basic building element of "ij "module

module Uj to Ui)

active, "p" passive xij set of binary interconnections

Technical University of Košice, Košice, Slovakia

provided the original work is properly cited.

\*Address all correspondence to: jozef.svetlik@tuke.sk

MPRC multiprofessional productions robotic center

Xi module input parameters (set requirements)

AMi unified modular unit (functional node, modular block, etc.)

Ui mutual relations (compatibility of ij module Ui to Uj,or of the ji

Yi module output parameters (properties, operating functions), "a"

Department of Manufacturing Machinery, Faculty of Mechanical Engineering,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

MTS modular technical system

This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-18-0413 and Research and development of rotary module with an unlimited degree rotation under Contract no. VEGA 1/0437/17.


Disadvantages of applying modularity to production systems:


### **Acknowledgements**

This work was supported by the Slovak Research and Development Agency under the Contract no. APVV-18-0413 and Research and development of rotary module with an unlimited degree rotation under Contract no. VEGA 1/0437/17.

### **Appendices and Nomenclature**


### **Author details**

Jozef Svetlík

Department of Manufacturing Machinery, Faculty of Mechanical Engineering, Technical University of Košice, Košice, Slovakia

\*Address all correspondence to: jozef.svetlik@tuke.sk

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### **References**

[1] Svetlík J. Modular Architecture of Production Technology. Košice: SjF TU; 2014. pp. 1-141. ISBN: 978-80-553-1928-5

[2] Demeč P, Svetlík J. Modules for Construction of Production Machines and Equipment - Exercise Tutorials. Košice: TU, SjF; 2010. pp. 1-76. ISBN: 978-80-553-0539-4

[3] Marek J et al. Design of CNC Machine Tools. Prague: MM publishing, s.r.o; 2010. pp. 1-421. ISBN: 978-80-254-7980-3

[4] Smrček J. Theory and Construction of Robotic Devices III, Robots on a Modular Principle. Košice: Faculty of Mechanical Engineering, Technical University of Košice; 2012

[5] Warnecke H-J et al. Fractal Plant. Žilina: Slovak Center of Productivity; 2000. pp. 1-208. ISBN: 80-968324-1-7

[6] Smrček J et al. Multiprofessional manufacturing Center with a robot new approach to creating automated manufacturing systems. Manufacturing Engineering. 2003:32-35. ISSN: 1335-7972

[7] Schunk [Internet]. 2012. Available from: www.schunk.com [Accessed: 06 November 2018]

[8] Riello S. Catalogue [Internet]. 2018. Available from: http://www. riellosistemi.it/en/catalogo/[Accessed: 12 November 2018]

[9] Gulan L. Modularity as a condition for platform creation. Mechanical Engineering. 2005:38. ISSN: 1335-2938

[10] Güdel [Internet]. 2018. Available from: www.gudel.com [Accessed: 28 January 2018]

[11] Bobovský Z. Design of a robot with a metamorphic kinematic structure

[dissertation thesis]. Faculty of Mechanical Engineering, Technical University of Košice; 2009

[12] Skařupa J, Mostýn V. Theory of Industrial Robots. Edition of Scientific and Professional Literature. Vienala, Košice: Faculty of Mechanical Engineering, Technical University of Košice; 2000. ISBN: 80-88922-35-6

[13] EMAG GmbH & Co. KG [Internet]. 2019. Available from: https://www. emag.com/machines/turning-machines/ modular-vl/vl-2.html

**25**

**Chapter 2**

Tools

*Oleg Krol*

**Abstract**

Parametric Modeling of Machine

The chapter deals with the problems of machine tool computer-aided design (CAD) based on the methods and means of parameterization for the main components of metal-cutting machine and equipment in the CAD "APM WinMachine" environment. The models and algorithms of parametric modeling for the configurations of machine tool milling and multioperational type by the criteria of maximum rigidity and minimum reduced load on the front spindle support are developed. The express procedure for generating the transverse layout of the main drive in the

**Keywords:** spatial gearbox configuration, transverse layout, multioperational

Modern computer-aided design (CAD) constructive and technological purposes are widely used methods and means of parameterization to increase productivity, on the one hand, and improve the quality of design decisions made, on the other hand. In the modern "medium-" and "heavy-" class systems, the presence of a parametric model is embedded in the ideology of the CAD systems themselves. The existence of a parametric description of an object is the basis for the entire design process [1]. The process of parametric modeling is associated with the use of model element parameters and the relationships between these parameters, which makes it possible to effectively generate various versions of designed objects using variation of parameters or geometric relations. Unlike traditional 2D and 3D constructions, the use of parameterization tools allows to create a mathematical model of a structure with parameters that, when changed, leads to change the configuration of the

One of the designer priorities is to create a conceptual design of the future product and the initial linking of structural elements. Parameterization is a very valuable tool, which allows for a short time to analyze various design schemes and

Parametric technology corporation (PTC) is considered the pioneer of parameterization, which in 1988 was the first to implement a procedure for creating

As is known, the design of machines and tools is primarily associated with the determination of the geometric shapes of detail and their relative position. Therefore, the history of automation is interconnected with the history of computer

multivariate design mode has been implemented.

structure, relative positions of the parts in the assembly, etc.

machine, parameterization, 3D model

**1. Introduction**

avoid fundamental errors.

parametric models.

#### **Chapter 2**

## Parametric Modeling of Machine Tools

*Oleg Krol*

#### **Abstract**

The chapter deals with the problems of machine tool computer-aided design (CAD) based on the methods and means of parameterization for the main components of metal-cutting machine and equipment in the CAD "APM WinMachine" environment. The models and algorithms of parametric modeling for the configurations of machine tool milling and multioperational type by the criteria of maximum rigidity and minimum reduced load on the front spindle support are developed. The express procedure for generating the transverse layout of the main drive in the multivariate design mode has been implemented.

**Keywords:** spatial gearbox configuration, transverse layout, multioperational machine, parameterization, 3D model

#### **1. Introduction**

Modern computer-aided design (CAD) constructive and technological purposes are widely used methods and means of parameterization to increase productivity, on the one hand, and improve the quality of design decisions made, on the other hand. In the modern "medium-" and "heavy-" class systems, the presence of a parametric model is embedded in the ideology of the CAD systems themselves. The existence of a parametric description of an object is the basis for the entire design process [1].

The process of parametric modeling is associated with the use of model element parameters and the relationships between these parameters, which makes it possible to effectively generate various versions of designed objects using variation of parameters or geometric relations. Unlike traditional 2D and 3D constructions, the use of parameterization tools allows to create a mathematical model of a structure with parameters that, when changed, leads to change the configuration of the structure, relative positions of the parts in the assembly, etc.

One of the designer priorities is to create a conceptual design of the future product and the initial linking of structural elements. Parameterization is a very valuable tool, which allows for a short time to analyze various design schemes and avoid fundamental errors.

Parametric technology corporation (PTC) is considered the pioneer of parameterization, which in 1988 was the first to implement a procedure for creating parametric models.

As is known, the design of machines and tools is primarily associated with the determination of the geometric shapes of detail and their relative position. Therefore, the history of automation is interconnected with the history of computer graphics. Software automation systems had to be invariant with respect to a set of computing tools and equipment input and output of graphic information. This has led to the emergence of various standardization systems. Thus, the standard for the basic graphic system consists of a functional description and specification of graphic functions for various programming languages.

In the field of design automation, the unification of the geometric modeling basic operations gave rise to invariant geometric cores intended for use in various CAD systems. As known, the core includes a library of CAD system basic mathematical functions, which defines and stores 3D forms, processes commands, saves results, and outputs the results of processing. The most widely used are two geometric cores: Parasolid (a product of Unigraphics Solutions) and ACIS (Spatial Technology). The Parasolid core, developed in 1988, becomes the core of solid modeling for CAD/CAM Unigraphics and, since 1996, the industry standard.

Parasolid V19.1 is the first version with support for 64-bit operating systems, using the full power of 64-bit technology to increase the productivity of the creative design process, creating a single 3D modeling platform for the entire product lifecycle management (PLM) industry.

Using the powerful Parasolid core in such well-known CAD Unigraphics allows solving all problems not in external applications, such as in CATIA, where parameterization is performed at the external module level, but at the core level and all its applications working the same way inside the system.

This in-system approach enables the provision of the entire product creation cycle: from the conceptual idea to the implementation within the system itself, without the additional use of external applications. It is also important that providing a unified environment for product development allows you to create a single digital model with which all project participants can work simultaneously. In this case, it is necessary to have sufficiently powerful means of parameterization, allowing for changes of complex structures in large assemblies, to be able to build complex associative links and also certain flexibility, since the product is constantly changing in the design process.

However, in almost all systems, such as Autodesk Mechanical Desktop, Unigraphics, CATIA, I-DEAS, etc., one parameterize of the British company D-CUBED is used. The D-CUBED parameterize includes two components: a sketcher designed to build a parametric profile, on the basis of which a 3D operation will be created, and a mathematical library that allows to link individual parts into assembly structures.

The D-CUBED parameterize, focused on 3D modeling, is ineffective in 2D drawing. The mathematics that successfully works on dozens of profile lines in the 3D system sketcher does not cope with thousands of interrelated elements of drawings. And the need for a complete dimensioning of the D-CUBED parametric model turns the process of parameterization of even a simple drawing into an almost unreal task.

One very useful use of parameterization is the creation of standard element libraries. The cost of creating a parameterization scheme pays off by reusing libraries. So, in the KOMPAS system of the company ASCON [2–5], a simpler approach to the creation of libraries of standard elements has been successfully implemented. It consists in the rejection of the expensive borrowed parameterize and the use of proprietary software for programming a large number of standard elements in plug-in libraries and the transfer to third-party companies of the means for creating such libraries. This allowed the use of an inexpensive software product for obtaining a large set of parameterized libraries.

The process of computer-aided design is constantly being improved. An example of an innovative approach in the field of CAD is the emergence of synchronous modeling (CT) tools proposed by Siemens PLM Software. CAD NX is the flagship CAD/CAM/CAE PLM system (formerly Unigraphics) [6, 7].

**27**

*Parametric Modeling of Machine Tools*

**machine tools**

**2.1 Build optimal layout**

4.Coaxial-mounted shafts, etc.

*DOI: http://dx.doi.org/10.5772/intechopen.90843*

construction history, which is now available in NX.

way can be inserted into a regular drawing as a parametric unit.

**2. Parametric modeling of transverse layout for metal-cutting** 

range Rn of modern machines can reach Rn = 100 ... 250) and high rigidity.

2.Rational distribution of gear ratios between several pairs of wheels.

3.Use of parallel transmissions, so that the power is transmitted over the parallel streams and the size of the SB is significantly reduced.

The use of CAD at various stages of designing assemblies of units and components of the machine involves the integration of a set of design and graphics modules, united by a single design concept with the ability to access common databases [12].

reduction of the radial dimensions can be carried out [9–11]:

1.The replacement of the three-shaft box to double-shaft.

The requirements for the design of specific machine tools vary depending on their types, while the construction of the basic layout is one of the most decisive steps. The layout of the machine is predetermined by the layout of the gearbox and the carrier system of the machine. The design of gearboxes for machine tools (main drive, feed box) is aimed at achieving a large range of rotational speeds (regulation

When designing speed boxes (SB), they seek to simplify the design and make it more compact by reducing the number of stages and limiting the gear ratios. So, the

This technology allows two main approaches to modeling: parametric design and direct editing. Thanks to synchronous technology, the possibilities of defining the functions of structural elements are expanded, which does not require the description of elements and their limitations manually. New methods for selecting objects automatically recognize logical and intra-element relationships even on models imported from other CAD systems, which contributes to the reuse of design data. For the first time, solutions are proposed for element-wise direct editing without a

CT technology allows setting fixed dimensions and parameters and designing rules at the time of creating or editing a model, without using the history of its creation. Synchronous modeling technology simultaneously synchronizes geometry and design rules by applying a new decision-making mechanism based on an expert system. It allows designers to use geometry from other CAD systems without creating it again. The suggestive selection technology automatically determines the functions of structural elements, without requiring manual description of the elements and their limitations. Consider the main features of the use of the parameterization toolkit in the APM WinMachine CAD system [8]. In the mode of creating a parametric model, the drawing or any part of it is drawn by creating a special parametric model. The parameters have a numerical expression in drawing units, and their set will determine the dimensional characteristics of the particular part. Parameters are set either numerically or through analytical expressions, and the drawing law is a sequence of drawing commands and their corresponding logical and analytical expressions with the specified parameters. The parametric model created in this

#### *Parametric Modeling of Machine Tools DOI: http://dx.doi.org/10.5772/intechopen.90843*

*Machine Tools - Design, Research, Application*

lifecycle management (PLM) industry.

changing in the design process.

ing a large set of parameterized libraries.

applications working the same way inside the system.

library that allows to link individual parts into assembly structures.

CAD/CAM/CAE PLM system (formerly Unigraphics) [6, 7].

graphic functions for various programming languages.

graphics. Software automation systems had to be invariant with respect to a set of computing tools and equipment input and output of graphic information. This has led to the emergence of various standardization systems. Thus, the standard for the basic graphic system consists of a functional description and specification of

In the field of design automation, the unification of the geometric modeling basic operations gave rise to invariant geometric cores intended for use in various CAD systems. As known, the core includes a library of CAD system basic mathematical functions, which defines and stores 3D forms, processes commands, saves results, and outputs the results of processing. The most widely used are two geometric cores: Parasolid (a product of Unigraphics Solutions) and ACIS (Spatial Technology). The Parasolid core, developed in 1988, becomes the core of solid modeling for CAD/CAM Unigraphics and, since 1996, the industry standard. Parasolid V19.1 is the first version with support for 64-bit operating systems, using the full power of 64-bit technology to increase the productivity of the creative design process, creating a single 3D modeling platform for the entire product

Using the powerful Parasolid core in such well-known CAD Unigraphics allows solving all problems not in external applications, such as in CATIA, where parameterization is performed at the external module level, but at the core level and all its

This in-system approach enables the provision of the entire product creation cycle: from the conceptual idea to the implementation within the system itself, without the additional use of external applications. It is also important that providing a unified environment for product development allows you to create a single digital model with which all project participants can work simultaneously. In this case, it is necessary to have sufficiently powerful means of parameterization, allowing for changes of complex structures in large assemblies, to be able to build complex associative links and also certain flexibility, since the product is constantly

However, in almost all systems, such as Autodesk Mechanical Desktop, Unigraphics, CATIA, I-DEAS, etc., one parameterize of the British company D-CUBED is used. The D-CUBED parameterize includes two components: a sketcher designed to build a parametric profile, on the basis of which a 3D operation will be created, and a mathematical

The D-CUBED parameterize, focused on 3D modeling, is ineffective in 2D drawing. The mathematics that successfully works on dozens of profile lines in the 3D system sketcher does not cope with thousands of interrelated elements of drawings. And the need for a complete dimensioning of the D-CUBED parametric model turns the process of parameterization of even a simple drawing into an almost unreal task. One very useful use of parameterization is the creation of standard element libraries. The cost of creating a parameterization scheme pays off by reusing libraries. So, in the KOMPAS system of the company ASCON [2–5], a simpler approach to the creation of libraries of standard elements has been successfully implemented. It consists in the rejection of the expensive borrowed parameterize and the use of proprietary software for programming a large number of standard elements in plug-in libraries and the transfer to third-party companies of the means for creating such libraries. This allowed the use of an inexpensive software product for obtain-

The process of computer-aided design is constantly being improved. An example of an innovative approach in the field of CAD is the emergence of synchronous modeling (CT) tools proposed by Siemens PLM Software. CAD NX is the flagship

**26**

This technology allows two main approaches to modeling: parametric design and direct editing. Thanks to synchronous technology, the possibilities of defining the functions of structural elements are expanded, which does not require the description of elements and their limitations manually. New methods for selecting objects automatically recognize logical and intra-element relationships even on models imported from other CAD systems, which contributes to the reuse of design data. For the first time, solutions are proposed for element-wise direct editing without a construction history, which is now available in NX.

CT technology allows setting fixed dimensions and parameters and designing rules at the time of creating or editing a model, without using the history of its creation. Synchronous modeling technology simultaneously synchronizes geometry and design rules by applying a new decision-making mechanism based on an expert system. It allows designers to use geometry from other CAD systems without creating it again. The suggestive selection technology automatically determines the functions of structural elements, without requiring manual description of the elements and their limitations.

Consider the main features of the use of the parameterization toolkit in the APM WinMachine CAD system [8]. In the mode of creating a parametric model, the drawing or any part of it is drawn by creating a special parametric model. The parameters have a numerical expression in drawing units, and their set will determine the dimensional characteristics of the particular part. Parameters are set either numerically or through analytical expressions, and the drawing law is a sequence of drawing commands and their corresponding logical and analytical expressions with the specified parameters. The parametric model created in this way can be inserted into a regular drawing as a parametric unit.

#### **2. Parametric modeling of transverse layout for metal-cutting machine tools**

#### **2.1 Build optimal layout**

The requirements for the design of specific machine tools vary depending on their types, while the construction of the basic layout is one of the most decisive steps. The layout of the machine is predetermined by the layout of the gearbox and the carrier system of the machine. The design of gearboxes for machine tools (main drive, feed box) is aimed at achieving a large range of rotational speeds (regulation range Rn of modern machines can reach Rn = 100 ... 250) and high rigidity.

When designing speed boxes (SB), they seek to simplify the design and make it more compact by reducing the number of stages and limiting the gear ratios. So, the reduction of the radial dimensions can be carried out [9–11]:


The use of CAD at various stages of designing assemblies of units and components of the machine involves the integration of a set of design and graphics modules, united by a single design concept with the ability to access common databases [12].

For the whole variety of machines of a certain group (type), it is impossible to use one or two SB structures. Most often, one has to either develop a new design using structural optimization methods or create a new version of the already known prototype design using the parametric optimization method. The parametric model is a sequence of drawing commands with the specified parameters. Parameters are set either numerically or through mathematical expressions.

A feature of the automated design process of a SB is a variety of alternative layout options and the need for adjustments and refinements to the specific features of the design object. The efficiency of the SB design depends on the adopted transverse layout (convolution), including the position of the output shaft. In the existing works on the design of the SB convolutions, the methodology and algorithm for constructing an effective variant of the box design according to the criteria of rigidity and reliability are not given.

In turn, the position of the output shaft in the optimal layout also depends on the position of the resultant cutting force *R*. Thus, for the range of milling and multioperational machine in the cutting process, tangential *Pz* and radial *Py* components of cutting forces *R* arise [13–15].

When determining the spatial position of gears that transmit torque to the machine spindle, it is necessary to consider two mutually exclusive situations:


The many options for the SB parts design their mutual arrangement, on the one hand, as well as the need to increase the productivity of the designer, on the other, make it possible to use a parametric modeling apparatus. It is this mechanism that allows reducing the development time of a new or modification of known structures, implemented in all modern CAD systems [15–17].

The parameterization mechanism is characterized by the presence of interconnections and constraints between the geometric objects that make up this structure (as opposed to nonparametric). At the same time, a part of the indicated interrelations and restrictions can be formed automatically when entering graphic information and the rest can be assigned by the user independently.

#### **2.2 Research problem statement**

In this chapter, a procedure for constructing parametric models of gearbox transverse layouts for machine tools has been developed. The solved problem is formulated as follows:

*To develop such a parametric model of the transverse assembly of the SB, which in one variant will provide the maximum rigidity of the designed machine (its spindle assembly), and in another variant, the minimum reduced load on the front spindle support.*

**29**

support.

*Parametric Modeling of Machine Tools*

**milling and boring machine**

**Figure 1.**

mechanical transmissions 3D."

**2.4 Optimal layout options**

(*P0, Pr*), is shown in **Figure 2**.

*DOI: http://dx.doi.org/10.5772/intechopen.90843*

**2.3 Parametric modeling of the speed box transverse layout for the drilling-**

*Spindle head of the DMB machine with SB: (a) kinematic diagram and (b) 3D model.*

ting and angle heads, trunk with a package of disk cutters).

As a prototype, we choose a horizontal drilling-milling boring machine (DMB machine) with advanced technological capabilities of the model SF68PF4 [18]. The layout of this machine involves moving along the horizontal guides of the headstock (Z axis), to which a vertical head is attached (**Figure 1a**) or additional devices (slot-

The headstock includes a spindle unit with a tool clamping mechanism and a camshaft transmitting rotation to a horizontal or vertical spindle using an automatic gear shifter. A two-stage gearbox is built into the structure under consideration, as well as a number of other parts and assemblies that ensure the normal operation of the headstock. Rotation from the electric motor through the poly-V-belt is transmitted to the input shaft and through gearing to the camshaft of the gearbox. From the latter, rotation is transmitted to the coupling of the vertical head or to the gear of the horizontal spindle (**Figure 1a**). The 3D model of the DMB machine headstock was developed in the environment of the integrated CAD system KOMPAS-3D (**Figure 1b**) using the specialized application "shafts and

The transverse convolution of the machine during the boring operation, taking into account the location of the cutting forces (*PZ*, *PY*) and the forces in the gearing

Analysis of the transverse arrangement shows the nonoptimal spatial position of the machine tool output shaft (*nv*) relative to the spindle (*nsp*), caused by nonparallelism of the resulting forces *P* and *R*. This leads to an increase in the reduced load on the front spindle bearing [19] and lowering its carrying capacity. However, this spatial arrangement simplifies the design of the gearbox housing, which is shown in **Figure 3**. In **Figure 3b** presents a three-dimensional model of mechanical gears that implement kinematic connections from an electric motor to a spindle unit. A three-dimensional model of the housing part has also been developed to provide the selected criterion for minimizing the reduced load on the front spindle

*Parametric Modeling of Machine Tools DOI: http://dx.doi.org/10.5772/intechopen.90843*

*Machine Tools - Design, Research, Application*

criteria of rigidity and reliability are not given.

nents of cutting forces *R* arise [13–15].

expressions.

For the whole variety of machines of a certain group (type), it is impossible to use one or two SB structures. Most often, one has to either develop a new design using structural optimization methods or create a new version of the already known prototype design using the parametric optimization method. The parametric model is a sequence of drawing commands with the specified parameters. Parameters are set either numerically or through mathematical

A feature of the automated design process of a SB is a variety of alternative layout options and the need for adjustments and refinements to the specific features of the design object. The efficiency of the SB design depends on the adopted transverse layout (convolution), including the position of the output shaft. In the existing works on the design of the SB convolutions, the methodology and algorithm for constructing an effective variant of the box design according to the

In turn, the position of the output shaft in the optimal layout also depends on the position of the resultant cutting force *R*. Thus, for the range of milling and multioperational machine in the cutting process, tangential *Pz* and radial *Py* compo-

When determining the spatial position of gears that transmit torque to the machine spindle, it is necessary to consider two mutually exclusive situations:

is used in machines for finishing processing methods.

which is permissible only for roughing.

tures, implemented in all modern CAD systems [15–17].

tion and the rest can be assigned by the user independently.

**2.2 Research problem statement**

formulated as follows:

1.Parallelism and unidirectionality of the cutting force *R* and the resultant force *Q* in gearing "output shaft spindle" provide the maximum rigidity of the spindle assembly (minimum deflection of the spindle front end). This option

2.Parallelism and directivity in opposite directions of the forces R and *Q* provide the least load on the front support (as the most loaded during the machine operation). In this case, the deflection of the front end of the shaft is maximum,

The many options for the SB parts design their mutual arrangement, on the one hand, as well as the need to increase the productivity of the designer, on the other, make it possible to use a parametric modeling apparatus. It is this mechanism that allows reducing the development time of a new or modification of known struc-

The parameterization mechanism is characterized by the presence of interconnections and constraints between the geometric objects that make up this structure (as opposed to nonparametric). At the same time, a part of the indicated interrelations and restrictions can be formed automatically when entering graphic informa-

In this chapter, a procedure for constructing parametric models of gearbox transverse layouts for machine tools has been developed. The solved problem is

*To develop such a parametric model of the transverse assembly of the SB, which in one variant will provide the maximum rigidity of the designed machine (its spindle assembly), and in another variant, the minimum reduced load on the front spindle* 

**28**

*support.*

**Figure 1.** *Spindle head of the DMB machine with SB: (a) kinematic diagram and (b) 3D model.*

#### **2.3 Parametric modeling of the speed box transverse layout for the drillingmilling and boring machine**

As a prototype, we choose a horizontal drilling-milling boring machine (DMB machine) with advanced technological capabilities of the model SF68PF4 [18]. The layout of this machine involves moving along the horizontal guides of the headstock (Z axis), to which a vertical head is attached (**Figure 1a**) or additional devices (slotting and angle heads, trunk with a package of disk cutters).

The headstock includes a spindle unit with a tool clamping mechanism and a camshaft transmitting rotation to a horizontal or vertical spindle using an automatic gear shifter. A two-stage gearbox is built into the structure under consideration, as well as a number of other parts and assemblies that ensure the normal operation of the headstock. Rotation from the electric motor through the poly-V-belt is transmitted to the input shaft and through gearing to the camshaft of the gearbox. From the latter, rotation is transmitted to the coupling of the vertical head or to the gear of the horizontal spindle (**Figure 1a**). The 3D model of the DMB machine headstock was developed in the environment of the integrated CAD system KOMPAS-3D (**Figure 1b**) using the specialized application "shafts and mechanical transmissions 3D."

#### **2.4 Optimal layout options**

The transverse convolution of the machine during the boring operation, taking into account the location of the cutting forces (*PZ*, *PY*) and the forces in the gearing (*P0, Pr*), is shown in **Figure 2**.

Analysis of the transverse arrangement shows the nonoptimal spatial position of the machine tool output shaft (*nv*) relative to the spindle (*nsp*), caused by nonparallelism of the resulting forces *P* and *R*. This leads to an increase in the reduced load on the front spindle bearing [19] and lowering its carrying capacity. However, this spatial arrangement simplifies the design of the gearbox housing, which is shown in **Figure 3**. In **Figure 3b** presents a three-dimensional model of mechanical gears that implement kinematic connections from an electric motor to a spindle unit. A three-dimensional model of the housing part has also been developed to provide the selected criterion for minimizing the reduced load on the front spindle support.

**Figure 2.**

*Transverse layout of the speed box for the machine model SF68VF4: (a) system of forces; and (b) fragment of the optimal layout parametric model.*

**Figure 3.**

*Speed box of the SF68VF4 machine (transverse layout): (a) design; and (b) housing and kinematics—3D gears.*

Rather simple design of the housing differs in two original solutions:


**31**

a parametric block.

**Figure 4.**

*Parametric Modeling of Machine Tools*

*DOI: http://dx.doi.org/10.5772/intechopen.90843*

The presence of the bottom of the nonrectilinear housing is an interesting version for the gearbox of a multifunctional machine. This design allows to implement such a spatial position of the shafts and the spindle, which ensures maximum

At the stage of preliminary design, it is efficient to use a parameterization apparatus, with the help of which it is possible to solve the two-criterion problem of constructing the transverse layout of a horizontal headstock with an integrated two-staged gearbox. For this, we will use the parametric capabilities of the CAD/

In this system (in the mode of creating a parametric model) is a design of a drawing (or any part of it); a special parametric model is formed. In this case, the APM Graph module is used, where a sequence of drawing commands and their corresponding logical and analytical expressions with the specified parameters are implemented. In **Figure 4** the command window is presented in the task of constructing a transverse layout (e.g., of constructing a "segment through two points"). A parametric model created in this way can be inserted into a regular drawing as

• Creation of a parametric model at the command level, which consists in linking graphical objects to those numerical data or communication equations that were set as variables. In this case, auxiliary variables can be used as input in the

• Indication of the primitive type being created and its index in commands for creating graphic primitives. Indexes are used in those commands for the

The algorithm for working with the parametric model includes:

rigidity of the spindle node and the machine tool as a whole.

CAE system of the APM WinMachine system [11, 20].

**2.5 Parameterization in the APM graph module**

*The command window of the APM graph module.*

parameters of subsequent commands.


#### **Figure 4.**

*Machine Tools - Design, Research, Application*

**30**

**Figure 3.**

**Figure 2.**

*the optimal layout parametric model.*

*gears.*

Rather simple design of the housing differs in two original solutions:

*Speed box of the SF68VF4 machine (transverse layout): (a) design; and (b) housing and kinematics—3D* 

*Transverse layout of the speed box for the machine model SF68VF4: (a) system of forces; and (b) fragment of* 

housing shape with minimal dimensions is maintained.

minimizing the size of the housing with fixed initial data.

1.On the right side of the housing, there is a joint for mounting the gear in a spatial layout. At the same time, the overall technologically feasible rectangular

2.In the lower part of the housing, a spherical shape is deepened, which allows

*The command window of the APM graph module.*

The presence of the bottom of the nonrectilinear housing is an interesting version for the gearbox of a multifunctional machine. This design allows to implement such a spatial position of the shafts and the spindle, which ensures maximum rigidity of the spindle node and the machine tool as a whole.

At the stage of preliminary design, it is efficient to use a parameterization apparatus, with the help of which it is possible to solve the two-criterion problem of constructing the transverse layout of a horizontal headstock with an integrated two-staged gearbox. For this, we will use the parametric capabilities of the CAD/ CAE system of the APM WinMachine system [11, 20].

#### **2.5 Parameterization in the APM graph module**

In this system (in the mode of creating a parametric model) is a design of a drawing (or any part of it); a special parametric model is formed. In this case, the APM Graph module is used, where a sequence of drawing commands and their corresponding logical and analytical expressions with the specified parameters are implemented. In **Figure 4** the command window is presented in the task of constructing a transverse layout (e.g., of constructing a "segment through two points").

A parametric model created in this way can be inserted into a regular drawing as a parametric block.

The algorithm for working with the parametric model includes:


execution of which. It is necessary to indicate one or more objects existing in the drawing (drawing a line parallel to the specified one, deleting objects, etc.).

• Editing the list of commands, consisting in the ability to remove a command from the list and replace it with another. Accordingly, the type of the parametric model may change, or errors due that together with the deleted command may appear. In this case any data necessary in subsequent commands was deleted.

The control points created with the object are also automatically indexed and can be used. In subsequent commands to directly access the created control points for the parametric model.

The designer has the ability to insert a parametric block into the drawing with a change in any of its parameters, including changing the scale and angle of inserted block rotation. The graphic part of the APM WinMachine system unified database [20] is similarly organized. It stores not only the numerical parameters of standard parts and elements but also their parametric models.

When inserting a graphical object from the database, the user has the opportunity not only to insert any standard element into the drawing, but also to change any of its parameters.

At the same time, to achieve the minimum load on the front spindle support, **Figure 5b**, it is necessary to adjust the housing design, while the housing connector should be made from the opposite side (**Figure 5a**).

Let us consider the basic design of the control gear for the wide-universal drilling-milling and boring machine with CNC model SF68PF4 [11], built into the two-stage SB of the main movement (**Figure 1**). In the mode of coordination with the rotary table, it provides processing of parts from all sides, as well as coaxial boring of holes without remounting the workpieces. The developed 3D model of

**33**

components:

**Figure 6.**

*with minimum driving force.*

tional machines.

tured products.

*Parametric Modeling of Machine Tools*

3D assembly is shown in **Figure 5b**.

*DOI: http://dx.doi.org/10.5772/intechopen.90843*

the SF68PF4 machine spindle node (SN) using KOMPAS-3D resources for setting parametric connections and associations between the individual components of the

*Command window of transverse layout parametric modeling: (a) command window; and (b) housing variant* 

bearings, each of which is mounted on dual angular contact bearings installed according to the "Tandem-O" scheme with preload in the form of different-height bushings. The authors developed a 3D model of SN assembling with a mechanism

for automatic tool clamping in the KOMPAS-3D system (**Figure 5b**).

The SN of this multioperational machine is considered as a beam on two elastic

To perform a comprehensive engineering analysis of both individual parts and assemblies, we will use the entire FEM module [19]. This module is equipped with a CAE library that implements solving engineering problems by the finite element method (FEM). In the process of solving, fixations and applied loads are set; matching faces are set (for FEM analysis of the assembly); FEM-mesh generation; calculation and viewing of results in the form of stress and displacement maps are performed. To study the stiffness, an elastic-deformation model of spindle node twosupport construction is built. It takes into account a set of modular equipment (consoles) of various sizes. A feature of the studied object is the presence of two

• Unified two-support spindle unit, which can be used in various multiopera-

• Tool blocks—a variable component, oriented to a different range of manufac-

Using the APM FEM module, all of the above actions were performed, and displacement fields on the set of spindle sections as beams were obtained. The analysis of the compliance characteristics for various multi-operation machines MTs 200PF4, MS51PF3, and SF68PF4 showed that the spindle assembly of the machine SF68PF4 is characterized by minimal flexibility. It has become possible due to the adoption of the optimal spatial layout. A study was made of the change

#### *Parametric Modeling of Machine Tools DOI: http://dx.doi.org/10.5772/intechopen.90843*

#### **Figure 6.**

*Machine Tools - Design, Research, Application*

for the parametric model.

of its parameters.

parts and elements but also their parametric models.

should be made from the opposite side (**Figure 5a**).

execution of which. It is necessary to indicate one or more objects existing in the drawing (drawing a line parallel to the specified one, deleting objects, etc.).

• Editing the list of commands, consisting in the ability to remove a command from the list and replace it with another. Accordingly, the type of the parametric model may change, or errors due that together with the deleted command may appear.

The control points created with the object are also automatically indexed and can be used. In subsequent commands to directly access the created control points

The designer has the ability to insert a parametric block into the drawing with a change in any of its parameters, including changing the scale and angle of inserted block rotation. The graphic part of the APM WinMachine system unified database [20] is similarly organized. It stores not only the numerical parameters of standard

When inserting a graphical object from the database, the user has the opportunity not only to insert any standard element into the drawing, but also to change any

At the same time, to achieve the minimum load on the front spindle support, **Figure 5b**, it is necessary to adjust the housing design, while the housing connector

Let us consider the basic design of the control gear for the wide-universal drilling-milling and boring machine with CNC model SF68PF4 [11], built into the two-stage SB of the main movement (**Figure 1**). In the mode of coordination with the rotary table, it provides processing of parts from all sides, as well as coaxial boring of holes without remounting the workpieces. The developed 3D model of

*Transverse layout with the minimum reduced power: (a) design; and (b) study of the spindle stiffness* 

In this case any data necessary in subsequent commands was deleted.

**32**

**Figure 5.**

*characteristics.*

*Command window of transverse layout parametric modeling: (a) command window; and (b) housing variant with minimum driving force.*

the SF68PF4 machine spindle node (SN) using KOMPAS-3D resources for setting parametric connections and associations between the individual components of the 3D assembly is shown in **Figure 5b**.

The SN of this multioperational machine is considered as a beam on two elastic bearings, each of which is mounted on dual angular contact bearings installed according to the "Tandem-O" scheme with preload in the form of different-height bushings. The authors developed a 3D model of SN assembling with a mechanism for automatic tool clamping in the KOMPAS-3D system (**Figure 5b**).

To perform a comprehensive engineering analysis of both individual parts and assemblies, we will use the entire FEM module [19]. This module is equipped with a CAE library that implements solving engineering problems by the finite element method (FEM). In the process of solving, fixations and applied loads are set; matching faces are set (for FEM analysis of the assembly); FEM-mesh generation; calculation and viewing of results in the form of stress and displacement maps are performed.

To study the stiffness, an elastic-deformation model of spindle node twosupport construction is built. It takes into account a set of modular equipment (consoles) of various sizes. A feature of the studied object is the presence of two components:


Using the APM FEM module, all of the above actions were performed, and displacement fields on the set of spindle sections as beams were obtained. The analysis of the compliance characteristics for various multi-operation machines MTs 200PF4, MS51PF3, and SF68PF4 showed that the spindle assembly of the machine SF68PF4 is characterized by minimal flexibility. It has become possible due to the adoption of the optimal spatial layout. A study was made of the change in the flexibility of the SN cantilever part for various standard sizes of tooling: with a spindle cone 30 AT5 in accordance with GOST 15945-82 for the model MS51PF3, with a cone 40 according to GOST 936-82 for model SF68PF4 and a cone 40AT5 according to GOST 15945-82 for model MTs200PF4V (**Figure 5b**).

To assess the change in the position of the gearbox shafts, a parametric modeling program was developed in the APM Graph (**Figure 6**).

Below is an example of a "message variable" (**Figure 7**), which is visualized in the working window in case of violation of the limit values *x* and *k*. For example, "Distance between the bottom of the housing and the wheel surface should exceed 24 mm" [21, 22].


**Figure 7.** *"Variable-message"—unacceptable distance.*

**Figure 8.** *Schemes of the influence of the intermediate links: (a and b) the intermediate gear; and (c) idle gear.*

**35**

*Parametric Modeling of Machine Tools*

previous review (**Figure 7**).

**3. Conclusion**

ing directions:

nature.

assembly.

models.

proximation to the best design option.

the CAD databases of machines.

*DOI: http://dx.doi.org/10.5772/intechopen.90843*

forces acting on the shaft bearings of this wheel.

The arrangement of the wheels relative to each other affects the magnitude acting on the force transmission elements, so that the power characteristics can be improved. So, the location of the intermediate gear wheel (**Figure 8a**, **b**) affects the

In **Figure 8b**, the forces in the engagement F1 and F2 are almost parallel, and the total force F acting on the supports is large. In **Figure 8a**, due to a change in the direction of the forces F1 and F2, they are largely compensated, and the resultant forces are less than in **Figure 8b**. It should be noted that for reversing transmission,

Rational mounted of wheels [21] also affects the accuracy characteristics of kinematic chains. The error of the idle gear in the kinematic chain (**Figure 8c**) can influence itself in the error of the output link by a magnification doubled. The location of the idle gear for a given direction of rotation also influences. In the diagram (**Figure 8c**), the dashed line shows the best (from the standpoint of accuracy)

The general rule of mounting requires that the transfer of rotation on the idle gear takes place at the minimum angle γ between points of contact 1 and 2. When reversing the transmission of the axis, it is desirable to place on one line, as in the

The introduction of parameterization mechanisms in the traditional design process makes the work of the designer as efficient as possible. At the same time, the improvement of the project decision-making process takes place in the follow-

1.The use of the developed parameterization mechanism significantly increases the efficiency of the metal-cutting machine tool study at various steps of design through the use of parametric models. This approach opens up the possibility of transition to solving complex project problems of a multi-criteria

2.The introduction of the parameterization mechanism contributes to the formulation and solution of designing machine tool problems and their components in the multivariate mode. This significantly increases the level of design decisions made both at the design stage of individual parts and their

3.A significant effect in increasing designer productivity is the ability to quickly solve the problems of the design process with recurrent information flows (reengineering), when a set of parametric models implements an effective ap-

4.The correctness of the results obtained is due to the use of a wide regulatory base (GOST, departmental normal) in the process of developing parametric

5.In the process of parametric modeling, it is possible to introduce into consideration a wide range of parts of a certain class, which reduces the set of necessary models for the design tasks of machine tools and makes more visible the size of

it is preferable to arrange the axis of the wheels in the same plane.

mounting scheme of the idle gear for a given direction of rotation [23].

#### *Parametric Modeling of Machine Tools DOI: http://dx.doi.org/10.5772/intechopen.90843*

*Machine Tools - Design, Research, Application*

24 mm" [21, 22].

in the flexibility of the SN cantilever part for various standard sizes of tooling: with a spindle cone 30 AT5 in accordance with GOST 15945-82 for the model MS51PF3, with a cone 40 according to GOST 936-82 for model SF68PF4 and a cone 40AT5

To assess the change in the position of the gearbox shafts, a parametric modeling

Below is an example of a "message variable" (**Figure 7**), which is visualized in the working window in case of violation of the limit values *x* and *k*. For example, "Distance between the bottom of the housing and the wheel surface should exceed

*Schemes of the influence of the intermediate links: (a and b) the intermediate gear; and (c) idle gear.*

according to GOST 15945-82 for model MTs200PF4V (**Figure 5b**).

program was developed in the APM Graph (**Figure 6**).

**34**

**Figure 8.**

**Figure 7.**

*"Variable-message"—unacceptable distance.*

The arrangement of the wheels relative to each other affects the magnitude acting on the force transmission elements, so that the power characteristics can be improved. So, the location of the intermediate gear wheel (**Figure 8a**, **b**) affects the forces acting on the shaft bearings of this wheel.

In **Figure 8b**, the forces in the engagement F1 and F2 are almost parallel, and the total force F acting on the supports is large. In **Figure 8a**, due to a change in the direction of the forces F1 and F2, they are largely compensated, and the resultant forces are less than in **Figure 8b**. It should be noted that for reversing transmission, it is preferable to arrange the axis of the wheels in the same plane.

Rational mounted of wheels [21] also affects the accuracy characteristics of kinematic chains. The error of the idle gear in the kinematic chain (**Figure 8c**) can influence itself in the error of the output link by a magnification doubled. The location of the idle gear for a given direction of rotation also influences. In the diagram (**Figure 8c**), the dashed line shows the best (from the standpoint of accuracy) mounting scheme of the idle gear for a given direction of rotation [23].

The general rule of mounting requires that the transfer of rotation on the idle gear takes place at the minimum angle γ between points of contact 1 and 2. When reversing the transmission of the axis, it is desirable to place on one line, as in the previous review (**Figure 7**).

#### **3. Conclusion**

The introduction of parameterization mechanisms in the traditional design process makes the work of the designer as efficient as possible. At the same time, the improvement of the project decision-making process takes place in the following directions:


Based on the proposed methods and parametrization facility, the following results were achieved:


### **Author details**

Oleg Krol Volodymyr Dahl East Ukrainian National University, Severodonetsk, Ukraine

\*Address all correspondence to: krolos@i.ua

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

**37**

*Parametric Modeling of Machine Tools*

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movement drive. Tools reliability and optimization technological systems. Collection of Scientific Papers.

[11] Krol OS, Shevchenko SV, Sokolov VI. Design of Metal-Cutting Tools in the Middle of APM WinMachine. Textbook. Lugansk: Publishing house of SNU; 2011. p. 388

[12] Taratynov OV, Averyanov OI, Klepikov VV, et al. Design and Calculation of Metal-Cutting

[13] Krol O, Sokolov V. Parametric modeling of gear cutting tools. In: Advances in Manufacturing II. Lecture Notes in Mechanical Engineering (Manufacturing 2019); 19-22 May 2019. Vol. 4. Poznan, Cham: Springer; 2019. pp. 3-11. DOI: 10.1007/978-3-030-16943-5\_1

[14] Krol O, Sokolov V. Parametric modeling of transverse layout for machine tool gearboxes II. In: Lecture Notes in Mechanical Engineering (Manufacturing 2019); 19-22 May 2019. Vol. 4. Poznan, Cham: Springer; 2019. pp. 122-130. DOI: 10.1007/978-3-030-16943-5\_11

[15] Krol O, Sokolov V. Parametric Modeling of Machine Tools for Designers. Sofia: Prof. Marin Drinov Academy Publishing House of Bulgarian Academy of Sciences; 2018. p. 112. DOI: 10.7546/

[16] Cherpakov BI, Averyanov OI, Adoyan GA, et al. Engineering. Encyclopedia. In: Cherpakov BI, editor. Metal-Cutting Machines and Woodworking Equipment. Vol. 4-7. Moscow: Machinery Engineering

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Academy of Sciences; 2018. p. 140. DOI:

[2] Fomin EP. Using parametric capabilities of KOMPAS-3D. CAD and

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revolution in CAD. CAD and Graphics.

Grigoriev S. Parametric capabilities of the graphic module APM graph of the APM WinMachine system. CAD and

[9] Bushuev VV. Fundamentals of Designing Machine Tools. Stankin:

[10] Krol OS, Krol AA. Parametrization of the transverse layout of the main

[5] Krol O, Sokolov V. Modelling of spindle nodes for machining centers. Journal of Physics: Conference Series. 2018;**1084**(012007):1-7. DOI: 10.1088/1742-6596/1084/1/012007

[4] Krol O, Sokolov V. Modeling of carrier system dynamics for metal-cutting machines. In: IEEE Proceedings 2018 International Russian Automation Conference (RusAutoCon); 9-16 September 2018. Sochi: IEEE; 2018. pp. 1-5. DOI: 10.1109/ *Parametric Modeling of Machine Tools DOI: http://dx.doi.org/10.5772/intechopen.90843*

#### **References**

*Machine Tools - Design, Research, Application*

results were achieved:

bearing.

spindle unit.

and rigidity.

**Author details**

\*Address all correspondence to: krolos@i.ua

provided the original work is properly cited.

Oleg Krol

Based on the proposed methods and parametrization facility, the following

1.Developed parametric models of transverse configurations (layout) of machine tools representative of the turning and milling groups. With the help of these models, built in accordance with the APM WinMachine syntax, it is possible to synthesize optimal transverse layouts both by the criterion of maximum rigidity and the criterion of the minimum load on the front spindle

2.Using the proposed algorithms for determining the spatial position of nodes in the main motion drive housing, it is possible to determine the distances from the external surfaces of gear wheels to the side walls and the bottom of the housing, as well as to estimate the degree of their approximation to the limit values. This will provide recommendations for reducing the size of the machine drives. On the other hand, the presence of a friendly interface in the APM Graph module promptly provides information to the designer about the unacceptable values of the gaps for rotating parts and the gearbox housing.

3.Based on the developed parametric layout models, recommendations are made for the improvement of housing parts. So, in the design of the main drive housing for the multipurpose machine, it is proposed to change the configuration of the housing bottom in order to ensure optimal spindle stiffness. In the machine drilling, milling and boring group model SF68VF4 proposed to perform the joint of the housing side wall to achieve the optimal design of the

4.Using the integrative capabilities of CAD/CAE/PDM "APM WinMachine" allows the designer to quickly estimate the magnitude of the discrepancy between the optimal and traditional factory solutions. So, with the help of the shaft design module APM Shaft in this work, the difference in the spindle stiffness values for the factory and optimum variants is determined. In this case, the designer receives the calculation form for the main indicators of strength

Volodymyr Dahl East Ukrainian National University, Severodonetsk, Ukraine

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

**36**

[1] Lee K. Basics of CAD (CAD/CAM/ CAE). Peter: Saint Petersburg; 2004. p. 560

[2] Fomin EP. Using parametric capabilities of KOMPAS-3D. CAD and Graphics. 2007;**10**:70-74

[3] Krol OS, Sokolov VI. 3D Modeling Of Machine Tools For Designers. Sofia: Prof. Marin Drinov Academy Publishing House of Bulgarian Academy of Sciences; 2018. p. 140. DOI: 10.7546/3d\_momtfd.2018

[4] Krol O, Sokolov V. Modeling of carrier system dynamics for metal-cutting machines. In: IEEE Proceedings 2018 International Russian Automation Conference (RusAutoCon); 9-16 September 2018. Sochi: IEEE; 2018. pp. 1-5. DOI: 10.1109/ rusautocon.2018.8501799

[5] Krol O, Sokolov V. Modelling of spindle nodes for machining centers. Journal of Physics: Conference Series. 2018;**1084**(012007):1-7. DOI: 10.1088/1742-6596/1084/1/012007

[6] Ushakov D. Synchronous technology—A simulation revolution from siemens PLM software. CAD/ CAM/CAE Observer. 2008;**4**(40):1-4

[7] Kurland R. Solid edge with synchronous technology—A revolution in CAD. CAD and Graphics. 2008;**9**:80-83

[8] Rozinsky S, Shanin D, Grigoriev S. Parametric capabilities of the graphic module APM graph of the APM WinMachine system. CAD and Graphics. 2001;**11**:37-40

[9] Bushuev VV. Fundamentals of Designing Machine Tools. Stankin: Moscow; 1992. p. 520

[10] Krol OS, Krol AA. Parametrization of the transverse layout of the main

movement drive. Tools reliability and optimization technological systems. Collection of Scientific Papers. 2009;**24**:164-168

[11] Krol OS, Shevchenko SV, Sokolov VI. Design of Metal-Cutting Tools in the Middle of APM WinMachine. Textbook. Lugansk: Publishing house of SNU; 2011. p. 388

[12] Taratynov OV, Averyanov OI, Klepikov VV, et al. Design and Calculation of Metal-Cutting Machines on a Computer: Textbook for Universities. Moscow: Publishing house of MGIU; 2002. p. 384

[13] Krol O, Sokolov V. Parametric modeling of gear cutting tools. In: Advances in Manufacturing II. Lecture Notes in Mechanical Engineering (Manufacturing 2019); 19-22 May 2019. Vol. 4. Poznan, Cham: Springer; 2019. pp. 3-11. DOI: 10.1007/978-3-030-16943-5\_1

[14] Krol O, Sokolov V. Parametric modeling of transverse layout for machine tool gearboxes II. In: Lecture Notes in Mechanical Engineering (Manufacturing 2019); 19-22 May 2019. Vol. 4. Poznan, Cham: Springer; 2019. pp. 122-130. DOI: 10.1007/978-3-030-16943-5\_11

[15] Krol O, Sokolov V. Parametric Modeling of Machine Tools for Designers. Sofia: Prof. Marin Drinov Academy Publishing House of Bulgarian Academy of Sciences; 2018. p. 112. DOI: 10.7546/ PMMTD.2018

[16] Cherpakov BI, Averyanov OI, Adoyan GA, et al. Engineering. Encyclopedia. In: Cherpakov BI, editor. Metal-Cutting Machines and Woodworking Equipment. Vol. 4-7. Moscow: Machinery Engineering Publishing; 2002. p. 672

[17] Avramova TM, Bushuev VV, Gilova LY, et al. In: Bushuev VV, editor. Metal Cutting Machines. Vol. 1. Moscow: Machinery Engineering Publishing; 2012. p. 608

**Chapter 3**

*Ľubomír Šooš*

the specific case of a machine tool.

design, testing

speeds at 440 m.min<sup>1</sup>

**39**

cutting edge will start to decrease.

**Abstract**

Headstock for High Speed

Machining - From Machining

Analysis to Structural Design

The progressive technological growth in developed industrial countries is characterized by the increasing range of manufactured parts, the variety of their shapes, and the development and usage of new non-traditional materials. At the same time, demands for high quality and production efficiency must be fulfilled. The essential function of machine tools is to make workpiece surfaces with the required geometry and with the required surface quality under economically efficient conditions. A significant benefit in increasing the efficiency and quality of machined surfaces was the development of high-speed machining. With the application of this machining method, the overall concept of the machine tool and the construction of its individual nodes have changed. The headstock has a significant impact on the quality of the final product and the overall productivity of the machine tool. Machine tools with integrated drive headstocks offer the users much greater performance and reliability. The aim of the presented chapter is the analysis of high-speed machining technology, a description of the structures of high-frequency headstocks and their individual parts, along with the design of a headstock with an integrated drive for

**Keywords:** headstock, high-speed cutting, ball bearings with angular contact,

Machining with high cutting speeds is associated with the name Carl Salamon [1]. This German researcher in the 1920s milled, for example, steel with cutting

German Patent No 523594 of 1931, creating a series of diagrams describing the impact of the cutting speed on the cutting temperature (**Figure 1)**. The experiment focused on machining non-ferrous metals, such as aluminum, copper, and brass, respectively [1]. The theory assumes that at a certain cutting speed (5–10 times higher than in conventional machining), the chip removal temperature at the

His experiments overturned Taylor's theory on "maximum cutting speeds," above which machine damage would occur. Salomon showed that for each toolwork piece couple, there exists a critical speed range at which machining is not

, and aluminum at up to 16,500 m.min<sup>1</sup>

. The trials ended in

**1. History, development, and advantages of speed machining**

[18] Krol O, Sokolov V. 3D modelling of angular spindle's head for machining centre. Journal of Physics Conference Series. 2019;**1278**(012002):1-9. DOI: 10.1088/1742-6596/1278/1/012002

[19] Shevchenko S, Mukhovaty A, Krol O. Geometric aspects of modifications of tapered roller bearings. Procedia Engineering. 2016;**150**:1107-1112. DOI: 10.1016/j. proeng.2016.07.07.221

[20] Zamriy AA. Practical Training Course CAD/CAE APM WinMachine. Teaching Aid. Moscow: Publishing House of APM; 2007. p. 144

[21] Reshetov DN. Details of Machines. Moscow: Machinery Engineering Publishing; 1989. p. 496

[22] Shevchenko S, Muhovaty A, Krol O. Gear clutch with modified tooth profiles. Procedia Engineering. 2017;**206**:979-984. DOI: 10.1016/j. proeng.2017.10.581

[23] Reshetov DN, Gusenkov AP, Drozdov YN. Mechanical engineering, encyclopedia. In: Reshetov DN, editor. Machine Parts, Structural Strength, Friction, Wear, Lubrication. Vol. IV-1. Moscow: Machinery Engineering Publishing; 1995. p. 864

#### **Chapter 3**

*Machine Tools - Design, Research, Application*

[18] Krol O, Sokolov V. 3D modelling of angular spindle's head for machining centre. Journal of Physics Conference Series. 2019;**1278**(012002):1-9. DOI: 10.1088/1742-6596/1278/1/012002

[19] Shevchenko S, Mukhovaty A, Krol O. Geometric aspects of modifications of tapered roller bearings. Procedia Engineering. 2016;**150**:1107-1112. DOI: 10.1016/j.

[20] Zamriy AA. Practical Training Course CAD/CAE APM WinMachine. Teaching Aid. Moscow: Publishing House of APM; 2007. p. 144

[21] Reshetov DN. Details of Machines. Moscow: Machinery Engineering

[22] Shevchenko S, Muhovaty A, Krol O. Gear clutch with modified tooth profiles. Procedia Engineering. 2017;**206**:979-984. DOI: 10.1016/j.

[23] Reshetov DN, Gusenkov AP, Drozdov YN. Mechanical engineering, encyclopedia. In: Reshetov DN, editor. Machine Parts, Structural Strength, Friction, Wear, Lubrication. Vol. IV-1. Moscow: Machinery Engineering

[17] Avramova TM, Bushuev VV, Gilova LY, et al. In: Bushuev VV, editor.

Metal Cutting Machines. Vol. 1. Moscow: Machinery Engineering

Publishing; 2012. p. 608

proeng.2016.07.07.221

Publishing; 1989. p. 496

proeng.2017.10.581

Publishing; 1995. p. 864

**38**

## Headstock for High Speed Machining - From Machining Analysis to Structural Design

*Ľubomír Šooš*

#### **Abstract**

The progressive technological growth in developed industrial countries is characterized by the increasing range of manufactured parts, the variety of their shapes, and the development and usage of new non-traditional materials. At the same time, demands for high quality and production efficiency must be fulfilled. The essential function of machine tools is to make workpiece surfaces with the required geometry and with the required surface quality under economically efficient conditions. A significant benefit in increasing the efficiency and quality of machined surfaces was the development of high-speed machining. With the application of this machining method, the overall concept of the machine tool and the construction of its individual nodes have changed. The headstock has a significant impact on the quality of the final product and the overall productivity of the machine tool. Machine tools with integrated drive headstocks offer the users much greater performance and reliability. The aim of the presented chapter is the analysis of high-speed machining technology, a description of the structures of high-frequency headstocks and their individual parts, along with the design of a headstock with an integrated drive for the specific case of a machine tool.

**Keywords:** headstock, high-speed cutting, ball bearings with angular contact, design, testing

#### **1. History, development, and advantages of speed machining**

Machining with high cutting speeds is associated with the name Carl Salamon [1]. This German researcher in the 1920s milled, for example, steel with cutting speeds at 440 m.min<sup>1</sup> , and aluminum at up to 16,500 m.min<sup>1</sup> . The trials ended in German Patent No 523594 of 1931, creating a series of diagrams describing the impact of the cutting speed on the cutting temperature (**Figure 1)**. The experiment focused on machining non-ferrous metals, such as aluminum, copper, and brass, respectively [1]. The theory assumes that at a certain cutting speed (5–10 times higher than in conventional machining), the chip removal temperature at the cutting edge will start to decrease.

His experiments overturned Taylor's theory on "maximum cutting speeds," above which machine damage would occur. Salomon showed that for each toolwork piece couple, there exists a critical speed range at which machining is not

**2. Parameters of high-speed machining**

*Compare technology of classical machining a HSC technology.*

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Table 1.**

**Figure 2.**

**41**

12,000 m.min<sup>1</sup> are used for grinding.

Cutting speed values in chip machining are dependent on technology, the material make-up of the cutting machine, and of the machined pieces. Therefore, there exists no unequivocal and general classification of machining according to cutting speeds. In professional literature, we most often encounter the concepts of classical, high-speed, and ultra-high-speed machining. It should be noted, however, that the classifications of the individual authors are considerably different or contradictory. According to individual machining technologies, König is probably the most systematic classification of cutting speeds [3, 4]. This author divides machining into classic and high speed (**Figure 2**). Back in the 1950s, Kronenberg carried out experiments with ultra-high cutting speeds of 9000–720,000 m.min<sup>1</sup>

**Technology of classical machining High-speed machining technology**

The contact time between tool and work is large Contact time is short Less accurate work piece More accurate work piece Cutting force is large Cutting force is low Poor surface finish Good surface finish

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

Material removal rate is low Material removal rate is high Cutting fluid is required Cutting fluid is not required

it can be seen that for stretching technology, the area of high-speed machining is in the 30–70 m.min<sup>1</sup> range, whereas in this area, cutting speeds from about 5000 to

*Cutting speed ranges for chip machining operations. (a) Turning, (b) milling, (c) drilling, (d) stretching, (e) reaming, (f) sawing, (g) grinding, ( ) classic machining, and ( ) high-speed machining.*

. In **Figure 2**,

**Figure 1.** *Machining temperatures at high speeds.*

possible. After overcoming this area, we can continue to work, while the temperature of cutting will drop significantly. In the early 1950s, research in the USA carried on from his results. For cutting thin-walled aircraft parts, the Lockhead and Boeing corporations, on a spindle mounted on rolling bearings (nmax = 18,000 min<sup>1</sup> , Pelm = 18 kW), achieved a milling speed of 3000 m.min<sup>1</sup> , [1–3]. In 1978 in Germany, and a year later in the USA, extensive research focused on the practical usage of highspeed machining was begun. In Germany alone, more than 40 leading firms participated on a project. On the basis of this cooperation at the beginning of 1980 at a university in Darmstadt was constructed an integrated milling spindle unit with asynchronous drive, with a spindle mounted on active magnetic bearings and cutting speeds of 2000–10,000 m.min<sup>1</sup> [4]. Over the next 3 years,, an economic variant on a roller bearing was constructed. Partial results from ongoing research confirmed the following advantages of high-speed milling:


A comparison of the advantages and disadvantages of conventional and highspeed machining is shown in the following table (**Table 1**).

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*


**Table 1.**

possible. After overcoming this area, we can continue to work, while the temperature of cutting will drop significantly. In the early 1950s, research in the USA carried on from his results. For cutting thin-walled aircraft parts, the Lockhead and Boeing corporations, on a spindle mounted on rolling bearings (nmax = 18,000 min<sup>1</sup>

and a year later in the USA, extensive research focused on the practical usage of highspeed machining was begun. In Germany alone, more than 40 leading firms participated on a project. On the basis of this cooperation at the beginning of 1980 at a university in Darmstadt was constructed an integrated milling spindle unit with asynchronous drive, with a spindle mounted on active magnetic bearings and cutting speeds of 2000–10,000 m.min<sup>1</sup> [4]. Over the next 3 years,, an economic variant on a roller bearing was constructed. Partial results from ongoing research confirmed the

• at increased cutting and feed speeds, the cutting force is significantly reduced, [3, 4]. This makes possible the machining of thin-walled parts without special preparations. A drop in cutting forces reduces the demands for rigidity of the

• a large part of the heat emerging in the machining process is taken away by chips. This significantly increases the durability of the machine, the work piece remains cold, and the roughness of its surface is decreased with equal or better

• a significant increase in cutting power leads to saving production time so as to

• high-speed cutting machine provides higher quality surface finish due to the

A comparison of the advantages and disadvantages of conventional and high-

speed machining is shown in the following table (**Table 1**).

dimensional precision, which leads to a saving in finishing operations;

Pelm = 18 kW), achieved a milling speed of 3000 m.min<sup>1</sup>

following advantages of high-speed milling:

save of production costs; and

reduced cutting pressure.

**40**

whole machine;

**Figure 1.**

*Machining temperatures at high speeds.*

*Machine Tools - Design, Research, Application*

,

, [1–3]. In 1978 in Germany,

*Compare technology of classical machining a HSC technology.*

#### **2. Parameters of high-speed machining**

Cutting speed values in chip machining are dependent on technology, the material make-up of the cutting machine, and of the machined pieces. Therefore, there exists no unequivocal and general classification of machining according to cutting speeds. In professional literature, we most often encounter the concepts of classical, high-speed, and ultra-high-speed machining. It should be noted, however, that the classifications of the individual authors are considerably different or contradictory. According to individual machining technologies, König is probably the most systematic classification of cutting speeds [3, 4]. This author divides machining into classic and high speed (**Figure 2**). Back in the 1950s, Kronenberg carried out experiments with ultra-high cutting speeds of 9000–720,000 m.min<sup>1</sup> . In **Figure 2**, it can be seen that for stretching technology, the area of high-speed machining is in the 30–70 m.min<sup>1</sup> range, whereas in this area, cutting speeds from about 5000 to 12,000 m.min<sup>1</sup> are used for grinding.

**Figure 2.**

*Cutting speed ranges for chip machining operations. (a) Turning, (b) milling, (c) drilling, (d) stretching, (e) reaming, (f) sawing, (g) grinding, ( ) classic machining, and ( ) high-speed machining.*

Modern machine tools have become more flexible capable of performing a range

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

In the conception of a machine, it is necessary to bring into consideration these

• in the design of a machine's frame, it is important to place emphasis on rigidity and damping capacities. It is very advantageous for this purpose to select the

• the working area of the machine must be perfectly shroud covered, with good chip transfer and with a suitably selected cooling and control system;

factors (kv ›1.8). This means on one side reducing to a minimum the weight of the moving parts, and on the other, securing maximum rigidity. We can solve

), with very short time constants and high strengthening

• feed units must be designed with consideration of maximum speeds

this compromise by using high-strength lightweight materials; and

• also important are the aspects of the modularity of the machine construction, together with the rapid replacement of the spindle unit and other machine nodes.

The headstock, as a construction node, has an important position in the overall

• the spindle should rotate with the high degree of accuracy. The accuracy of rotation is determined by the axial and radial run out of the spindle nose and these must not exceed certain permissible values that are specified depending upon the required machining accuracy. The rotational accuracy is influenced at the most by the stillness and accuracy of the spindle bearings, particularly the

• the spindle unit must have high static stiffness. The stiffness of the unit is made up of the stiffness of the spindle unit proper and the spindle bearings. Machining accuracy is influenced on bending, axial as well as torsional stiffness. In series configurations of individual machine nodes, headstock is usually the weakest construction node, which is a limiting member to achieve the required rigidity of the entire machine concept, as a criterion for ensuring

• the spindle unit must have high dynamic stiffness and damping. Poor dynamic stability of the spindle unit adversely affects the dynamic behavior of the

• the maximum rotational frequencies of the headstock is a limiting factor of the maximum cutting speed of machine tools and thus of the overall machine production. These maximum rotational frequencies can no longer be ensured for HSC by conventional indirect drives with gear or belt. It should be emphasized that these two factors, stiffness and maximum speed, act in

For high-speed machining, headstocks with integrated drive—"Electrospindles" are usually used (**Figure 5**) [5]. This has solved the problem of providing rotational

of programmed tasks.

(vr—15-20 m. min<sup>1</sup>

machine frame in high-strength concrete;

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

machine concept. This is for the following reasons:

one located at the front end;

the required standstill accuracy;

machine tool as a whole; and

opposite directions.

**43**

frequencies for high cutting speed.

factors:

**Figure 3.** *Cutting speed ranges for milling.*

The dependence of cutting speed for individual types of machined material is shown in **Figure 3** [4]. It is clear from the figure that the lowest cutting speed is when milling nickel and its alloys and the highest when milling aluminum and its alloys.

It must be remembered that cutting speed is also a function of the cut material and other accompanying machining conditions (cooling, etc.). To create the most general idea of cutting speed values, we can break down machining according to **Figure 4**.

#### **3. Headstock—heart of machine tool**

The issue of high-speed machining is very expansive. It is suitable therefore to divide this area into the conception of the machine as a unit and the development of its individual constructional nodes and elements.

#### **Figure 4.**

*Outlining of cutting speed ranges for speed machining: (A) classic machining, (B) transitional area, (C) high-speed machining, and (D) ultra-high-speed machining.*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

Modern machine tools have become more flexible capable of performing a range of programmed tasks.

In the conception of a machine, it is necessary to bring into consideration these factors:


The headstock, as a construction node, has an important position in the overall machine concept. This is for the following reasons:


For high-speed machining, headstocks with integrated drive—"Electrospindles" are usually used (**Figure 5**) [5]. This has solved the problem of providing rotational frequencies for high cutting speed.

The dependence of cutting speed for individual types of machined material is shown in **Figure 3** [4]. It is clear from the figure that the lowest cutting speed is when milling nickel and its alloys and the highest when milling aluminum and its alloys. It must be remembered that cutting speed is also a function of the cut material and other accompanying machining conditions (cooling, etc.). To create the most general idea of cutting speed values, we can break down machining according to

The issue of high-speed machining is very expansive. It is suitable therefore to divide this area into the conception of the machine as a unit and the development of

*Outlining of cutting speed ranges for speed machining: (A) classic machining, (B) transitional area,*

**Figure 4**.

**Figure 4.**

**42**

**Figure 3.**

*Cutting speed ranges for milling.*

*Machine Tools - Design, Research, Application*

**3. Headstock—heart of machine tool**

its individual constructional nodes and elements.

*(C) high-speed machining, and (D) ultra-high-speed machining.*

• maximum symmetry—for the reasons of symmetrical thermal expansions;

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

The requirements put on the spindle are concentrated on the spindle geometric rigidity, selection of design material, and shape configuration of diameters. The selection of design material for the spindle is conditioned particularly by mechanical properties of the essential core structure, which are by the modulus of elasticity *E* and by the coefficient of relative damping *D*. The spindles made of steel comply with the requirements of high static rigidity. The relative spindle quality measure is its specific rigidity, that is, the spindle nose rigidity compared with the spindle weight. The spindle natural frequency and the dynamic characteristics of the headstock are also connected with it. Composite materials (graphite epoxide) start to be used for high-speed spindles. This spindle is lighter, and it does not require such a

The shape configuration of diameters shall be simple to the maximum possible extent. Those configurations are rational, where the minimum number of graduated diameters can be found and the difference between diameters is determined only by

The spindle end that protrudes from the headstock body is called the front spindle nose. When designing the spindle, the great attention must be paid to the suitable adaptation of the spindle nose so that it can provide the optimum tool clamping (through the clamping shank) or the optimum work piece chucking (e.g., by means of the chuck) [8]. This connection must be a quick, precise, rigid, and reliable one. The type execution and the shape of the spindle nose depend on the technology, type, and size machine tool and on the required accuracy of working.

A limiting factor determining cutting speed is bearings. At high frequencies, it must be sufficiently rigid, accurate, and with high durability. The selection of the bearing type in particular supports in the bearing system of the machine tool spindle is always the matter of a compromise among the high rigidity, maximal frequencies of rotation, and offered possibilities of the utilizable building area in the headstock body. In particular, electromagnetic and rolling bearing nodes made of radial angular contact ball bearings are used for receiving spindles for high-speed machining. High revolutions may be achieved by the application of an aero-static bearing whose very low rigidity makes it suitable only for grinding operations.

In the mid-twentieth century, a successful magnetic levitation bearing was successfully demonstrated. This first successful magnetic bearing utilized electromagnets to provide attractive forces in the five degrees of freedom (with rotation being the sixth). Active servo control stabilized the system by using feedback signals from position sensors in each axis of control to vary the currents flowing through the

• minimum quantity of holes—holes decrease rigidity; and

• statically predestined design—it increases rigidity.

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

the types and dimensions of applied bearing models.

**5. Work spindle**

big diameter [7].

**6. Spindle bearing system**

**6.1 Electromagnetic bearings**

various electromagnets.

**45**

#### **Figure 5.**

*Spindle unit with integrated drive (SKF) [5].*

**Figure 6.** *Headstock morphology.*

The electrospindle consists of the particular parts and external peripheries, which together provide the required functions of the whole assembly group (**Figure 6**) [6]. The essential headstock parts include the spindle, bearings system, the tool clamping system or the work piece chucking system, and the body of the headstock. The peripheral devices can include integrated or external systems determined to drive the spindle, lubricate the bearings, provide cooling, spindle indexing, and monitoring.

#### **4. Box of headstock**

For high-speed machining, tubular shapes of headstocks like box type are more used. Recently, in addition to tubes made of steel, bodies with a tube wound from fiber composites have recently been used. These include headstocks from Weiss or Step-tech. Based on the elasticity and rigidity knowledge, it is possible to form the approximate solution of every headstock type. Requirements put on the headstock body boxes are:

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*


#### **5. Work spindle**

The requirements put on the spindle are concentrated on the spindle geometric rigidity, selection of design material, and shape configuration of diameters. The selection of design material for the spindle is conditioned particularly by mechanical properties of the essential core structure, which are by the modulus of elasticity *E* and by the coefficient of relative damping *D*. The spindles made of steel comply with the requirements of high static rigidity. The relative spindle quality measure is its specific rigidity, that is, the spindle nose rigidity compared with the spindle weight. The spindle natural frequency and the dynamic characteristics of the headstock are also connected with it. Composite materials (graphite epoxide) start to be used for high-speed spindles. This spindle is lighter, and it does not require such a big diameter [7].

The shape configuration of diameters shall be simple to the maximum possible extent. Those configurations are rational, where the minimum number of graduated diameters can be found and the difference between diameters is determined only by the types and dimensions of applied bearing models.

The spindle end that protrudes from the headstock body is called the front spindle nose. When designing the spindle, the great attention must be paid to the suitable adaptation of the spindle nose so that it can provide the optimum tool clamping (through the clamping shank) or the optimum work piece chucking (e.g., by means of the chuck) [8]. This connection must be a quick, precise, rigid, and reliable one. The type execution and the shape of the spindle nose depend on the technology, type, and size machine tool and on the required accuracy of working.

#### **6. Spindle bearing system**

A limiting factor determining cutting speed is bearings. At high frequencies, it must be sufficiently rigid, accurate, and with high durability. The selection of the bearing type in particular supports in the bearing system of the machine tool spindle is always the matter of a compromise among the high rigidity, maximal frequencies of rotation, and offered possibilities of the utilizable building area in the headstock body. In particular, electromagnetic and rolling bearing nodes made of radial angular contact ball bearings are used for receiving spindles for high-speed machining. High revolutions may be achieved by the application of an aero-static bearing whose very low rigidity makes it suitable only for grinding operations.

#### **6.1 Electromagnetic bearings**

In the mid-twentieth century, a successful magnetic levitation bearing was successfully demonstrated. This first successful magnetic bearing utilized electromagnets to provide attractive forces in the five degrees of freedom (with rotation being the sixth). Active servo control stabilized the system by using feedback signals from position sensors in each axis of control to vary the currents flowing through the various electromagnets.

The electrospindle consists of the particular parts and external peripheries, which together provide the required functions of the whole assembly group (**Figure 6**) [6]. The essential headstock parts include the spindle, bearings system, the tool clamping system or the work piece chucking system, and the body of the headstock. The peripheral devices can include integrated or external systems deter-

For high-speed machining, tubular shapes of headstocks like box type are more used. Recently, in addition to tubes made of steel, bodies with a tube wound from fiber composites have recently been used. These include headstocks from Weiss or Step-tech. Based on the elasticity and rigidity knowledge, it is possible to form the approximate solution of every headstock type. Requirements put on the headstock

mined to drive the spindle, lubricate the bearings, provide cooling, spindle

indexing, and monitoring.

**Figure 5.**

**Figure 6.**

*Headstock morphology.*

*Spindle unit with integrated drive (SKF) [5].*

*Machine Tools - Design, Research, Application*

**4. Box of headstock**

body boxes are:

**44**

Several individual electromagnets, usually from 8 to 12, were arranged in a north-south-north-south configuration around each end of a levitated shaft to provide radial support. This design approach, which results in a multiplicity of magnetic flux reversals around the circumference of the shaft, is known as heteropolar. Most commercially available magnetic bearing systems utilize this technology. A typical heteropolar magnetic bearing system is shown in the below **Figure 7** [9].

The stator, composed of an array of stationary electromagnets, generates powerful attraction forces that suspend the ferrous rotor shaft in the center of the magnetic field (with the help of an active servo-control unit). The active magnetic bearings are divided into radial, axial, and conical bearings (**Figure 8**).

In addition to the zero mechanical passive resistances, these active bearings have the property that they can determine, for example, the cutting force value, thanks to the active check of the bearing. The reached maximum speed is up to 100,000 min<sup>1</sup> and at small special spindles up to 150,000 min<sup>1</sup> . The spindle seating on active magnetic bearings uses attractive forces. The spindle position sensors provide the back response for the control system. The sensors send the linear output signal, and they can work in a wide range of operating temperatures. The correct bearing function is ensured by costly control electronics, which prevents faster application of these bearings in the practice. Roller "emergency" bearings are also used in the machine tool spindles carried in the active magnetic bearings (**Figure 9**). The main task of these bearings, which do not work at the normal spindle run, is to provide the trouble-free spindle stop in the case of the sudden electricity blackout.

**Figure 7.** *Principle of electromagnetic bearings.*

**Figure 8.** *Type of magnetic bearings.*

**6.2 Roller bearings**

Mk *= 1.5 nm), [10].*

**Figure 9.**

other (direction arrangement).

spindles at machine tools are:

• run accuracy;

• durability;

**47**

*6.2.1 Observed parameters of the bearing groups*

Radial angular contact ball bearings are used almost exclusively for highfrequency spindle bearings with integrated drive [11]. It is generally valid, that radial ball bearings with angular contact are recently unequivocally the most often used bearings for mounting of high-speed machine tool spindles. The reason is that their different design, their dimensional range, the contact angle values, the preload intensity, and the way of bearing arrangement in the assemblage provide the greatest scope of possibilities how to solve the compromise between the limit speed and maximum rigidity. "Spindle" bearings are manufactured in different dimensional ranges (72, 70, 719, 718) with the design of antifriction body guiding on the inside ring (B) or on the outside ring (A), with different contact angle values (12°, 15°, 25°, and 26°), with the polyamide cage (TB), with the required accuracy (P2, PA9, SP, UP), with various arrangement ways (DB, DF, DT and their combinations), with light (UL), middle (UM), or heavy preload (US) [5]. The bearings made with the higher accuracy degrees are used to seat the spindles. The axial loading capacity of the bearing increases proportionally when the contact angle increases, but the value of limit rotation frequencies decreases. It order to catch bigger radial or axial forces, the bearings are mounted in assemblages created from three, four, or five bearings. Radial load is distributed to all bearings in the group (shape arrangement), and axial load is distributed to all bearings joined behind each

*, and* P *= 11 kW,*

*Electrospindle with electromagnetic bearings (Ibag, HF 120 MA 80 K,* nmax *= 70,000 min<sup>1</sup>*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

The important parameters of the bearing groups specified to seat the working

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

#### **Figure 9.**

Several individual electromagnets, usually from 8 to 12, were arranged in a north-south-north-south configuration around each end of a levitated shaft to provide radial support. This design approach, which results in a multiplicity of magnetic flux reversals around the circumference of the shaft, is known as heteropolar. Most commercially available magnetic bearing systems utilize this technology. A typical heteropolar magnetic bearing system is shown in the below **Figure 7** [9]. The stator, composed of an array of stationary electromagnets, generates pow-

erful attraction forces that suspend the ferrous rotor shaft in the center of the magnetic field (with the help of an active servo-control unit). The active magnetic

seating on active magnetic bearings uses attractive forces. The spindle position sensors provide the back response for the control system. The sensors send the linear output signal, and they can work in a wide range of operating temperatures. The correct bearing function is ensured by costly control electronics, which prevents faster application of these bearings in the practice. Roller "emergency" bearings are also used in the machine tool spindles carried in the active magnetic bearings (**Figure 9**). The main task of these bearings, which do not work at the normal spindle run, is to provide the trouble-free spindle stop in the case of the

In addition to the zero mechanical passive resistances, these active bearings have the property that they can determine, for example, the cutting force value, thanks

. The spindle

bearings are divided into radial, axial, and conical bearings (**Figure 8**).

to the active check of the bearing. The reached maximum speed is up to 100,000 min<sup>1</sup> and at small special spindles up to 150,000 min<sup>1</sup>

sudden electricity blackout.

*Machine Tools - Design, Research, Application*

*Principle of electromagnetic bearings.*

**Figure 7.**

**Figure 8.**

**46**

*Type of magnetic bearings.*

*Electrospindle with electromagnetic bearings (Ibag, HF 120 MA 80 K,* nmax *= 70,000 min<sup>1</sup> , and* P *= 11 kW,* Mk *= 1.5 nm), [10].*

#### **6.2 Roller bearings**

Radial angular contact ball bearings are used almost exclusively for highfrequency spindle bearings with integrated drive [11]. It is generally valid, that radial ball bearings with angular contact are recently unequivocally the most often used bearings for mounting of high-speed machine tool spindles. The reason is that their different design, their dimensional range, the contact angle values, the preload intensity, and the way of bearing arrangement in the assemblage provide the greatest scope of possibilities how to solve the compromise between the limit speed and maximum rigidity. "Spindle" bearings are manufactured in different dimensional ranges (72, 70, 719, 718) with the design of antifriction body guiding on the inside ring (B) or on the outside ring (A), with different contact angle values (12°, 15°, 25°, and 26°), with the polyamide cage (TB), with the required accuracy (P2, PA9, SP, UP), with various arrangement ways (DB, DF, DT and their combinations), with light (UL), middle (UM), or heavy preload (US) [5]. The bearings made with the higher accuracy degrees are used to seat the spindles. The axial loading capacity of the bearing increases proportionally when the contact angle increases, but the value of limit rotation frequencies decreases. It order to catch bigger radial or axial forces, the bearings are mounted in assemblages created from three, four, or five bearings. Radial load is distributed to all bearings in the group (shape arrangement), and axial load is distributed to all bearings joined behind each other (direction arrangement).

#### *6.2.1 Observed parameters of the bearing groups*

The important parameters of the bearing groups specified to seat the working spindles at machine tools are:


#### *6.2.1.1 Run accuracy*

The run accuracy spindle bearing system is limited by the accuracy of bearings and by the accuracy of bearing surfaces—connection parts. The accuracy of antifriction bearings is understood as the accuracy of their dimensions and run. The limit values for the accuracy of dimensions and run are mentioned in ISO 492 and ISO 199 standards. The accuracy of connection parts is understood as geometric shape and position deviations which can be admissible at the manufacture of the spindle and headstock box. The bearing manufacturer prescribes the admissible geometric shape and position deviations of bearing surfaces (**Figure 10**). At the assembly of bearing, it is necessary to observe matching of inside and outside bearing diameters to provide the required radial preload.

#### *6.2.1.2 Durability*

The calculation of bearing durability is generally known [6]. It is described by the international ISO 281/l standard. When durability is calculated, we usually use the modified equation of durability that expresses the durability in operation hours. The following relation is used for the bearing durability in hours:

$$L\_{h10} = \left(\frac{C\_d}{P}\right)^p \cdot \frac{10^6}{60.n\_s} \text{ [h]}\tag{1}$$

The spindle bearings transfer the combined radial-axial load. When the selected

The significance of the bearing rigidity in the particular supports is considerable

The rigidity of the bearing assemblage made from the radial angular contact ball bearings can be described mathematically as the multiple parametric function [11].

It depends on the number of bearings *i*, dimensional rank, size and design of bearings *z, dw*, contact angle *α*, preload size *Fp*, or deformations due to preload *δps,*

Three essential states can generally take place in the bearing assemblage made

• the preload axially loaded state [the TBT assemblage loaded by the axial force

• the preload state [e.g., the assemblage joined from two shape-arranged

*Essential states of bearing assemblages: (a) DB preload state, (b) TBT preload—axially loaded state, and*

and frame conditions (bearing accuracy, assembly, and cooling).

*Cr*,*<sup>a</sup>* <sup>¼</sup> *f i*, *<sup>z</sup>*, *dw*, *<sup>α</sup>*, *Fp*, *<sup>δ</sup>ps* , *Fr*,*<sup>a</sup>*, *Fn*, *<sup>T</sup>* (3)

at the spindles having a bigger diameter, where the rigidity of the bearing assemblage in the particular supports is the limiting factor necessary to reach the required rigidity of the complete seating, as the tool how to provide its accurate operation. The total rigidity is the criterion of the body resistance against the

*P* ¼ *X:Fr* þ *Y Fa* ½ � N (2)

bearing type (selected bearings) is calculated, the combined radial-axial load is

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

recalculated to the so-called equivalent dynamic load:

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

where

*6.2.1.3 Rigidity*

*Fr* is the radial force [N]; *X* is the radial coefficient; *Fa* is the axial force [N]; and *Y* is the axial coefficient.

influence of external forces.

from the radial ball bearings [6]:

bearings (**Figure 11a**)];

(**Figure 11b**)]; and

*(c) QBC preload -radially loaded state.*

**Figure 11.**

**49**

where *P* is the equivalent dynamic load [N];

*Cd* is the dynamic loading capacity of the bearing [N];

exponent: *p* = 3, for ball bearings;

*p* = 10/3, for needle, spherical-roller and tapered roller bearings; and

*ns* is mean frequencies of bearing rotation [min�<sup>1</sup> ].

The equivalent dynamic load *P* at roller bearings corresponds to the intensity of reactions in the particular supports. However, the methodology is not unified how to calculate the equivalent load at bearing groups made of the radial angular contact ball bearings.

**Figure 10.** *Prescribed shape and position deviations (SKF).*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

The spindle bearings transfer the combined radial-axial load. When the selected bearing type (selected bearings) is calculated, the combined radial-axial load is recalculated to the so-called equivalent dynamic load:

$$P = X.F\_r + YF\_a \text{ [N]} \tag{2}$$

where *Fr* is the radial force [N]; *X* is the radial coefficient; *Fa* is the axial force [N]; and *Y* is the axial coefficient.

#### *6.2.1.3 Rigidity*

• rigidity;

• temperature.

*6.2.1.1 Run accuracy*

*6.2.1.2 Durability*

ball bearings.

**Figure 10.**

**48**

• high-speed run; and

*Machine Tools - Design, Research, Application*

The run accuracy spindle bearing system is limited by the accuracy of bearings

antifriction bearings is understood as the accuracy of their dimensions and run. The limit values for the accuracy of dimensions and run are mentioned in ISO 492 and ISO 199 standards. The accuracy of connection parts is understood as geometric shape and position deviations which can be admissible at the manufacture of the spindle and headstock box. The bearing manufacturer prescribes the admissible geometric shape and position deviations of bearing surfaces (**Figure 10**). At the assembly of bearing, it is necessary to observe matching of inside and outside

The calculation of bearing durability is generally known [6]. It is described by the international ISO 281/l standard. When durability is calculated, we usually use the modified equation of durability that expresses the durability in operation hours.

> *:* <sup>10</sup><sup>6</sup> 60*:ns*

> > ].

½ � h (1)

and by the accuracy of bearing surfaces—connection parts. The accuracy of

bearing diameters to provide the required radial preload.

The following relation is used for the bearing durability in hours:

*Cd* is the dynamic loading capacity of the bearing [N];

*ns* is mean frequencies of bearing rotation [min�<sup>1</sup>

where *P* is the equivalent dynamic load [N];

exponent: *p* = 3, for ball bearings;

*Prescribed shape and position deviations (SKF).*

*Lh*<sup>10</sup> <sup>¼</sup> *Cd*

*P <sup>p</sup>*

*p* = 10/3, for needle, spherical-roller and tapered roller bearings; and

The equivalent dynamic load *P* at roller bearings corresponds to the intensity of reactions in the particular supports. However, the methodology is not unified how to calculate the equivalent load at bearing groups made of the radial angular contact

The significance of the bearing rigidity in the particular supports is considerable at the spindles having a bigger diameter, where the rigidity of the bearing assemblage in the particular supports is the limiting factor necessary to reach the required rigidity of the complete seating, as the tool how to provide its accurate operation. The total rigidity is the criterion of the body resistance against the influence of external forces.

The rigidity of the bearing assemblage made from the radial angular contact ball bearings can be described mathematically as the multiple parametric function [11].

$$\mathbf{C}\_{r,a} = f\left(i, z, d\_w, a, F\_p, \left(\delta\_{p^s}\right), F\_{r,a}, F\_n, T\right) \tag{3}$$

It depends on the number of bearings *i*, dimensional rank, size and design of bearings *z, dw*, contact angle *α*, preload size *Fp*, or deformations due to preload *δps,* and frame conditions (bearing accuracy, assembly, and cooling).

Three essential states can generally take place in the bearing assemblage made from the radial ball bearings [6]:


**Figure 11.**

*Essential states of bearing assemblages: (a) DB preload state, (b) TBT preload—axially loaded state, and (c) QBC preload -radially loaded state.*

• the preload radially loaded state [the QBC assemblage loaded by the radial force (**Figure 11c**)].

Preload of the spindle bearings at the spindle assembly enables to increase the working accuracy and rigidity of the whole seating. On the other hand, the increased preload initiates the temperature origination in the bearing, which has the negative influence on critical rotation frequencies of the bearing or of the bearing assemblage. Two angular contact bearings are preload by the force *Fp* according to ČSN/STN 024615,

$$F\_p = k \, \text{C}\_d \, \text{10}^{-2} \tag{4}$$

Based on this knowledge, the simplified equations for the calculation of the

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

mean rigidity value were deduced in works [12, 13].

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

*<sup>C</sup>*rsi <sup>¼</sup> <sup>3</sup>*:*10‐<sup>3</sup>

<sup>4</sup> *:z*2*=*<sup>3</sup>

*:k* 2*=*3 *<sup>δ</sup>* � *i*

The resulting radial rigidity of the bearing group with the shape-arranged bear-

The following relation was deduced according to [13] for the approximate radial rigidity value of the bearing assemblage made from two shape-arranged groups:

ð Þ *α*<sup>1</sup>

At the omission of the contact angle change due to the axial force and under the presumption that the contact angles are the same ones at both joined groups, the

> *<sup>k</sup><sup>δ</sup>* <sup>¼</sup> ffiffiffiffiffiffiffiffiffiffiffiffiffiffi 1, 25*dw*

Under the presumption that the contact angles *α*<sup>1</sup> ¼ *α*<sup>2</sup> **are the same ones at the shape-arranged bearings in the group or** *i2* = 0 for the direction-arranged bearings in the group, the relationship between radial and axial stiffness is

*Crz* <sup>¼</sup> *Caz*

<sup>2</sup> � <sup>1</sup>

The high-speed run criterion is the quality criterion of the node regarding to the reached frequencies of rotation. Regarding to the high-speed run of the bearing nodes, the node systems are analyzed in work [6]. The particular designing solutions of the existing seating are divided into three essential groups in this work. The high-speed run parameter can reach the value K = (2–2.7).106 mm. min�<sup>1</sup> at the special high frequency groups. For the limit values, it is suitable to use the special bearings with the optimized design, high accuracy, and with the utilization of materials having the favorable physical and mechanical properties (e.g., silicon

� 1 þ *i* 2*=*3

*<sup>p</sup>* � cos <sup>2</sup>ð Þ *<sup>α</sup>*<sup>1</sup> sin <sup>1</sup>*=*<sup>3</sup>

ð Þ *α*<sup>1</sup>

� 1 þ *i* 2*=*3 2 *i* 2*=*3 1

p (14)

*tg*2*<sup>α</sup>* (15)

" #

*i* 2*=*3

*<sup>p</sup>* � cos <sup>2</sup>ð Þ *<sup>α</sup>*<sup>1</sup> sin <sup>1</sup>*=*<sup>3</sup>

<sup>2</sup>*=*<sup>3</sup> � F1*<sup>=</sup>*<sup>3</sup>

*<sup>p</sup>* � cos <sup>2</sup>ð Þ *<sup>α</sup>* sin <sup>1</sup>*=*<sup>3</sup>

*C*rz ¼ *C*rs1 þ *Crs*<sup>2</sup> (11)

<sup>2</sup> � cos <sup>2</sup>ð Þ� *<sup>α</sup>*<sup>2</sup> sin <sup>1</sup>*=*<sup>3</sup>

" #

<sup>1</sup> � cos <sup>2</sup>ð Þ� *<sup>α</sup>*<sup>1</sup> sin <sup>1</sup>*=*<sup>3</sup>

ð Þ *α*<sup>1</sup>

ð Þ *α*<sup>2</sup>

(12)

(13)

ð Þ *<sup>α</sup>* (10)

*6.2.1.6 Directional rigidity*

ings will then be:

*<sup>C</sup>*rz <sup>¼</sup> <sup>3</sup>*:*10‐<sup>3</sup>

simplified as:

*6.2.1.7 High-speed run*

nitride Si3N4).

**51**

<sup>4</sup> � *<sup>z</sup>*<sup>2</sup>*=*<sup>3</sup> � *<sup>k</sup>*

relation becomes the simplified form:

*<sup>C</sup>*rz <sup>¼</sup> <sup>3</sup>*:*10‐<sup>3</sup>

<sup>4</sup> � *<sup>z</sup>*<sup>2</sup>*=*<sup>3</sup> � *<sup>k</sup>*<sup>2</sup>*=*<sup>3</sup>

where *kδ* we can calculate according to the equation

*<sup>δ</sup>* � *i* 2*=*3 <sup>1</sup> � <sup>F</sup><sup>1</sup>*=*<sup>3</sup>

2*=*3 *<sup>δ</sup>* � *i* 2*=*3 <sup>1</sup> � <sup>F</sup><sup>1</sup>*=*<sup>3</sup>

The preload value for more bearings will be increased depending on the relation:

$$F\_{p^s} = k \, \text{C}\_d \, \text{i}^{0, \mathcal{I}} \, \text{10}^{-2} \tag{5}$$

#### *6.2.1.4 Axial rigidity*

The axial rigidity importance comes to the foreground especially at facing, milling, drilling, and grinding. In the system "spindle-bearing," the axial forces are almost always caught by the point-contact bearings. The axial rigidity is then given by the relation:

$$\mathbf{C}\_{a} = \frac{F\_{a}}{\delta\_{a}} \tag{6}$$

The following is valid for the approximate axial rigidity value according to [11]:

$$\mathbf{C}\_{ax} = \frac{3.10^{-3}}{2} \mathbf{z}^{\frac{2}{5}} \cdot \mathbf{k}\_{\delta}^{\frac{2}{5}} \cdot \dot{\mathbf{i}}\_{1}^{\frac{2}{5}} \cdot F\_{p}^{\frac{4}{5}} \cdot \sin^{\frac{5}{5}} \alpha\_{1} \left[ \mathbf{1} + \frac{\dot{i}\_{2}^{\frac{2}{5}} \cdot \sin^{\frac{5}{5}} \alpha\_{1}}{\dot{i}\_{1}^{\frac{2}{5}} \cdot \sin^{\frac{5}{5}} \alpha\_{2}} \right] \tag{7}$$

After the omission of the contact angle change due to the axial force and under the presumption that the contact angles are the same ones at both joined groups, the relation becomes the simplified form:

$$\mathbf{C}\_{ax} = \frac{\mathbf{3.10}^{-3}}{2} \mathbf{z}^{\frac{2}{3}} \cdot \mathbf{k}\_{\delta}^{\frac{2}{3}} \cdot \dot{\mathbf{i}}\_{1}^{\frac{2}{3}} \cdot F\_{p}^{\frac{1}{3}} \cdot \sin^{\frac{5}{3}} \alpha\_{1} \left[ \mathbf{1} + \frac{\dot{i}\_{2}^{\frac{2}{3}}}{\dot{i}\_{1}^{\frac{2}{3}}} \right] \tag{8}$$

*6.2.1.5 Radial rigidity*

$$\mathbf{C}\_r = \frac{F\_r}{\delta\_r} \tag{9}$$

For the reason that the load is not distributed equally, the rigidity calculation is rather difficult and it cannot be almost realized without application of computer technology. It is necessary to determine theoretically and to verify experimentally the deformation course on the load at the preload point-contact bearing groups. The research of the bearing groups made from the radial angular contact ball bearings [12] showed that the deformation course is almost linear at the preload bearing groups up to the certain critical load. For the calculation and testing of radial ball bearings arrangement to nodes, we have developed an expert mathematical model allowing calculation of stiffness, limit frequencies, and bearing node durability.

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

Based on this knowledge, the simplified equations for the calculation of the mean rigidity value were deduced in works [12, 13].

#### *6.2.1.6 Directional rigidity*

• the preload radially loaded state [the QBC assemblage loaded by the radial

Preload of the spindle bearings at the spindle assembly enables to increase the

increased preload initiates the temperature origination in the bearing, which has the negative influence on critical rotation frequencies of the bearing or of the bearing assemblage. Two angular contact bearings are preload by the force *Fp* according to

The preload value for more bearings will be increased depending on the relation:

*0*,*7*

*Fp* <sup>¼</sup> *<sup>k</sup>:Cd:10*�*<sup>2</sup>* (4)

*:10*�*<sup>2</sup>* (5)

(6)

(7)

(8)

(9)

working accuracy and rigidity of the whole seating. On the other hand, the

*Fps* ¼ *k:Cd:i*

The axial rigidity importance comes to the foreground especially at facing, milling, drilling, and grinding. In the system "spindle-bearing," the axial forces are almost always caught by the point-contact bearings. The axial rigidity is then given

> *Ca* <sup>¼</sup> *Fa δa*

The following is valid for the approximate axial rigidity value according to [11]:

After the omission of the contact angle change due to the axial force and under the presumption that the contact angles are the same ones at both joined groups, the

> *Cr* <sup>¼</sup> *Fr δr*

For the reason that the load is not distributed equally, the rigidity calculation is rather difficult and it cannot be almost realized without application of computer technology. It is necessary to determine theoretically and to verify experimentally the deformation course on the load at the preload point-contact bearing groups. The research of the bearing groups made from the radial angular contact ball bearings [12] showed that the deformation course is almost linear at the preload bearing groups up to the certain critical load. For the calculation and testing of radial ball bearings arrangement to nodes, we have developed an expert mathematical model allowing calculation of stiffness, limit frequencies, and bearing node durability.

<sup>3</sup>*α*<sup>1</sup> 1 þ

*i* 2 3 <sup>2</sup> � sin <sup>5</sup> <sup>3</sup>*α*<sup>1</sup>

" #

*i* 2 3 <sup>1</sup> � sin <sup>5</sup> <sup>3</sup>*α*<sup>2</sup>

<sup>3</sup>*α*<sup>1</sup> 1 þ

" #

force (**Figure 11c**)].

*Machine Tools - Design, Research, Application*

ČSN/STN 024615,

*6.2.1.4 Axial rigidity*

by the relation:

*Caz* <sup>¼</sup> <sup>3</sup>*:*10�<sup>3</sup>

relation becomes the simplified form:

*6.2.1.5 Radial rigidity*

**50**

<sup>2</sup> *<sup>z</sup>* 2 <sup>3</sup> � *k* 2 3 *<sup>δ</sup>* � *i* 2 3 <sup>1</sup> � *F* 1 3 *<sup>p</sup>* � sin <sup>5</sup>

*Caz* <sup>¼</sup> <sup>3</sup>*:*10�<sup>3</sup>

<sup>2</sup> *<sup>z</sup>* 2 <sup>3</sup> � *k* 2 3 *<sup>δ</sup>* � *i* 2 3 <sup>1</sup> � *F* 1 3 *<sup>p</sup>* � sin <sup>5</sup>

$$\mathbf{C\_{rsi}} = \frac{\mathbf{3.10^{-3}}}{4} \cdot x^{2/3} \cdot \mathbf{k\_{\delta}^{2/3}} \cdot \mathbf{i^{2/3}} \cdot \mathbf{F\_{p}^{1/3}} \cdot \frac{\cos^{2}(a)}{\sin^{1/3}(a)}\tag{10}$$

The resulting radial rigidity of the bearing group with the shape-arranged bearings will then be:

$$\mathbf{C\_{rz}} = \mathbf{C\_{rs1}} + \mathbf{C\_{r2}} \tag{11}$$

The following relation was deduced according to [13] for the approximate radial rigidity value of the bearing assemblage made from two shape-arranged groups:

$$\mathbf{C\_{rz}} = \frac{\mathbf{3.10^{-3}}}{4} \cdot \mathbf{z}^{2/3} \cdot \mathbf{k}\_{\delta}^{2/3} \cdot \mathbf{i}\_1^{2/3} \cdot \mathbf{F}\_p^{1/3} \cdot \frac{\cos^2(a\_1)}{\sin^{1/3}(a\_1)} \cdot \left[\mathbf{1} + \frac{\mathbf{i}\_2^{2/3} \cdot \cos^2(a\_2) \cdot \sin^{1/3}(a\_1)}{\mathbf{i}\_1^{2/3} \cdot \cos^2(a\_1) \cdot \sin^{1/3}(a\_2)}\right] \tag{12}$$

At the omission of the contact angle change due to the axial force and under the presumption that the contact angles are the same ones at both joined groups, the relation becomes the simplified form:

$$\mathbf{C\_{rz}} = \frac{3.10^{\cdot 3}}{4} \cdot z^{2/3} \cdot k\_{\delta}^{2/3} \cdot i\_1^{2/3} \cdot \mathbf{F}\_p^{1/3} \cdot \frac{\cos^2(a\_1)}{\sin^{1/3}(a\_1)} \cdot \left[\mathbf{1} + \frac{i\_2^{2/3}}{i\_1^{2/3}}\right] \tag{13}$$

where *kδ* we can calculate according to the equation

$$k\_{\delta} = \sqrt{\mathbf{1}, \mathbf{2} \mathbf{5} d\_{w}} \tag{14}$$

Under the presumption that the contact angles *α*<sup>1</sup> ¼ *α*<sup>2</sup> **are the same ones at the shape-arranged bearings in the group or** *i2* = 0 for the direction-arranged bearings in the group, the relationship between radial and axial stiffness is simplified as:

$$C\_{rz} = \frac{C\_{ar}}{2} \cdot \frac{1}{\text{tg}\,2a} \tag{15}$$

#### *6.2.1.7 High-speed run*

The high-speed run criterion is the quality criterion of the node regarding to the reached frequencies of rotation. Regarding to the high-speed run of the bearing nodes, the node systems are analyzed in work [6]. The particular designing solutions of the existing seating are divided into three essential groups in this work. The high-speed run parameter can reach the value K = (2–2.7).106 mm. min�<sup>1</sup> at the special high frequency groups. For the limit values, it is suitable to use the special bearings with the optimized design, high accuracy, and with the utilization of materials having the favorable physical and mechanical properties (e.g., silicon nitride Si3N4).

*Machine Tools - Design, Research, Application*

$$K\_r = n\_\pi \cdot d\_s \left[ \min^{-1} \cdot \text{mm} \right] \tag{16}$$

The following relation is used for the determination of the critical frequencies of the bearing groups *nz.*

$$n\_x = n\_{l\max} \cdot f\_1 \cdot f\_2 \cdot f\_3 \cdot f\_4 \dots \dots f\_n \left[ \min^{-1} \right] \tag{17}$$

where *nl* max is the critical frequencies of the bearing rotation and *fi* is the coefficient describing the bearing group and conditions of its work (the number of bearings, preload, accuracy of bearings, kinematics, heat removal, lubrication, etc.). Their importance is different in dependence of the particular sources.

The reduction of antifriction body dimensions results in the decrease of the centrifugal force, for which the following is valid:

$$F\_o = m \frac{d\_s}{2} \cdot o^2 \tag{18}$$

(up to 10 times) of rolling elements, still persisting problems with the homogeneity

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

In the bearing groups, where no external heat sources act, the shaft temperature, the spindle temperature as well as the temperature of inside bearing rings and of the antifriction bodies are higher than the temperature of external bearing rings and of the headstock body sleeve. Due to the heat drop at the same expansibility coefficient, the dilatation of the spindle, bearing rings, and balls is bigger than the expansibility of the surrounding parts in the radial direction as well as in the axial

For headstocks where high demands are placed on the range of rotational frequencies or temperature, it is advantageous to vary the amount of bearing preload directly during work. In order to increase the speed ranges and the service life of the spindle bearing, due consideration must be given to temperature optimization of the bearing when designing the spindle. The temperature of the bearing system varies depending on the temperature gradient, type and arrangement of the bearings (DB, DF, DT), assemblies, contact angle, bearing size, and the distances of bearings in the note and of the individual supports. There are known systems of active control of bearing preload of high-frequency headstocks and peripheral

*Temperature change compensation. (a)* US06422757; Active piezoelectric spindle bearings preload

adjustment mechanism*, [14]. (b) Motor spindle SKF with movable rear support [5].*

Δ*lr*,*<sup>a</sup>* ¼ *υ<sup>t</sup>* � *lr*,*<sup>a</sup>* � Δ*t* (19)

of ceramic materials, and the identification of failures.

direction. According to [11], its value is described by the equation:

*6.2.1.8 Temperature*

*Hybrid bearings (SKF).*

**Figure 13.**

**Figure 14.**

**53**

where *m* is the antifriction body weight and *ds* is the bearing mean diameter.

Such bearings are economical and reliable. The issue of decrease in centrifugal forces at high-frequency rotations is solved by reducing the weight of the rolling elements. This is achieved by changing the dimensional series of bearings and by changing the ball material.

Using bearings with smaller cross-sections, for example, 718, 719 instead of bearings with bigger cross-sections (70, 72), reduces the diameter of the balls. Reducing the diameter of the rolling elements makes it possible to increase the high frequency of rotation of the bearing (**Figure 12a**) and at the same time increases the number of balls to achieve higher bearing stiffness (**Figure 12b**) [5]. With constant external diameters, the internal diameter of the bearings increases, which is suitable from the standpoint of reducing spindle deflection, increasing its drilling, and increasing the critical revolutions of the spindle.

Roller bearings as well as ball bearings can be made as so-called "hybrid ones," which means that the bearing rings are made of steel and antifriction bodies are ceramic. The advantage of hybrid bearings by the same size compared to steel bearings is their lower centrifugal forces, frictional moment, and higher radial and axial stiffness (**Figure 13**). Disadvantages include the high manufacturing costs

**Figure 12.**

*Changing the dimensional series of bearings—contact ball bearings (SKF) [5] (a) relative speed capability, and (b) relative stiffness.*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Figure 13.** *Hybrid bearings (SKF).*

*Kr* <sup>¼</sup> *nz* � *ds* min �**<sup>1</sup>** � mm (16)

<sup>2</sup> � *<sup>ω</sup>*<sup>2</sup> (18)

*nz* <sup>¼</sup> *nl* max � *<sup>f</sup>* <sup>1</sup> � *<sup>f</sup>* <sup>2</sup> � *<sup>f</sup>* <sup>3</sup> � *<sup>f</sup>* <sup>4</sup> … … *<sup>f</sup> <sup>n</sup>* min �**<sup>1</sup>** (17)

The following relation is used for the determination of the critical frequencies of

where *nl* max is the critical frequencies of the bearing rotation and *fi* is the coefficient describing the bearing group and conditions of its work (the number of bearings, preload, accuracy of bearings, kinematics, heat removal, lubrication, etc.).

The reduction of antifriction body dimensions results in the decrease of the

*ds*

where *m* is the antifriction body weight and *ds* is the bearing mean diameter. Such bearings are economical and reliable. The issue of decrease in centrifugal forces at high-frequency rotations is solved by reducing the weight of the rolling elements. This is achieved by changing the dimensional series of bearings and by

Using bearings with smaller cross-sections, for example, 718, 719 instead of bearings with bigger cross-sections (70, 72), reduces the diameter of the balls. Reducing the diameter of the rolling elements makes it possible to increase the high frequency of rotation of the bearing (**Figure 12a**) and at the same time increases the number of balls to achieve higher bearing stiffness (**Figure 12b**) [5]. With constant external diameters, the internal diameter of the bearings increases, which is suitable from the standpoint of reducing spindle deflection, increasing its drilling, and

Roller bearings as well as ball bearings can be made as so-called "hybrid ones," which means that the bearing rings are made of steel and antifriction bodies are ceramic. The advantage of hybrid bearings by the same size compared to steel bearings is their lower centrifugal forces, frictional moment, and higher radial and axial stiffness (**Figure 13**). Disadvantages include the high manufacturing costs

*Changing the dimensional series of bearings—contact ball bearings (SKF) [5] (a) relative speed capability, and*

*Fo* ¼ *m*

Their importance is different in dependence of the particular sources.

centrifugal force, for which the following is valid:

increasing the critical revolutions of the spindle.

the bearing groups *nz.*

*Machine Tools - Design, Research, Application*

changing the ball material.

**Figure 12.**

**52**

*(b) relative stiffness.*

(up to 10 times) of rolling elements, still persisting problems with the homogeneity of ceramic materials, and the identification of failures.

#### *6.2.1.8 Temperature*

In the bearing groups, where no external heat sources act, the shaft temperature, the spindle temperature as well as the temperature of inside bearing rings and of the antifriction bodies are higher than the temperature of external bearing rings and of the headstock body sleeve. Due to the heat drop at the same expansibility coefficient, the dilatation of the spindle, bearing rings, and balls is bigger than the expansibility of the surrounding parts in the radial direction as well as in the axial direction. According to [11], its value is described by the equation:

$$
\Delta l\_{r,t} = \nu\_t \cdot l\_{r,t} \cdot \Delta t \tag{19}
$$

For headstocks where high demands are placed on the range of rotational frequencies or temperature, it is advantageous to vary the amount of bearing preload directly during work. In order to increase the speed ranges and the service life of the spindle bearing, due consideration must be given to temperature optimization of the bearing when designing the spindle. The temperature of the bearing system varies depending on the temperature gradient, type and arrangement of the bearings (DB, DF, DT), assemblies, contact angle, bearing size, and the distances of bearings in the note and of the individual supports. There are known systems of active control of bearing preload of high-frequency headstocks and peripheral

#### **Figure 14.**

*Temperature change compensation. (a)* US06422757; Active piezoelectric spindle bearings preload adjustment mechanism*, [14]. (b) Motor spindle SKF with movable rear support [5].*

devices and sensors of important parameters, the monitoring of which has a decisive influence on ensuring correct operation of the spindle. The solution may be, for example, active piezoelectric spindle bearings preload adjustment mechanism (**Figure 14a**) [14]. Bearings in the rear support must also allow thermal expansion of the entire spindle. Advantageously, it is possible to minimize the change in bias in the bearing by resolving the bearing arrangement in the individual supports (**Figure 14b**) [5].

#### **7. Spindle motor**

Desired performance and revolution characteristics place ever increasing demands on the construction of the spindle unit. The type of propulsion and bearing is the decisive component for providing the stated characteristics. Incorporating the drive directly into the spindle unit has successfully solved transmission problems at high speeds. In this way, the stress from the drive forces onto the spindle is eliminated and its accuracy is increased (**Figure 15**).

Both single-direction and alternating drives can in principle be used for integrated spindle units. Despite very good control properties, DC drives have known operational and technical drawbacks resulting from mechanical commutation devices—the commutator. For eliminating this deficiency, electronic commutation (Stromag and Bosch companies) is suitable. The use of synchronous frequency controlled drives is conditioned on the development of new hard magnetic materials [6]. In addition to the known Alnico alloys and hard ferrites, cobalt-based alloys characterized by high permanent induction (0.8–1 T) and high density are being developed, while the demagnetization curve is almost straight. An Italian company Polymotor is producing ring drives for integrated spindle units on a base of SmCO5 alloy. In an effort to reduce the consumption of rare earths and hence the cost of permanent materials, materials that do not contain rare earth are being developed. Mn-Al-C alloys are well known, as are materials containing CO, Cr, and Fe.

At the present time, the majority of manufacturers of integrated drive spindle units use asynchronic frequency controlled drives due to their advantages (**Table 2**).

For securing the drive parameters, it is necessary to choose a suitable frequency shifter, which processes the frequency of the 50 Hz network with an output frequency of up to 3000 Hz. They are thyristors or transistors with sinusoidal output. The main advantage of static converters compared to rotary converters is in

continuous speed change control. Acceleration and braking work in a very short time without thermal load on the engine. There is no slip during braking, which is

**Scheme Describe**

• General purpose application • Maintenance-free operation over long

• It does not remove heat • Grease has smaller durability than oil

• Water cannot get to the bearing area (oil mist forces it out) Disadvantages • Ambient contamination

> • Oil quantity depends on temperature and viscosity

• Water cannot get to the bearing area

• Water cannot get to the bearing area

• No worsening of lubricant

• Stable bearing temperature • Low generation of heat from excess of lubricant

• Difficult determination of

periods,

Advantages • No worsening of lubricant quality

Advantages • Stable bearing temperature

Disadvantages • High friction moment • Higher price • Oil leakage at vertical application

Advantages • It is environmental friendly

Disadvantages • High price

quality

oil quantity

Disadvantages • Lower speed

Grease Advantages • Low price

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

High-speed machining is associated with the development of new cutting materials such as cutting ceramics, synthetic polycrystalline diamond, and cubic boron nitride. In addition to the development of cutting materials with the new

very advantageous for precise positioning of the spindle.

*Comparison of lubrication methods for spindle bearings [6].*

**8. Peripheral**

**55**

**Lubrication method**

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

Oil-mist (oil-mist lubrication)

Oil-jet (oil-jet lubrication/ cooling)

Oil-air (oil-air lubrication)

**Table 2.**

**8.1 Clamping system**

**Figure 15.** *Electric spindle motors (SIEMENS).*


#### *Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Table 2.**

devices and sensors of important parameters, the monitoring of which has a decisive influence on ensuring correct operation of the spindle. The solution may be, for example, active piezoelectric spindle bearings preload adjustment mechanism (**Figure 14a**) [14]. Bearings in the rear support must also allow thermal expansion of the entire spindle. Advantageously, it is possible to minimize the change in bias in

the bearing by resolving the bearing arrangement in the individual supports

Desired performance and revolution characteristics place ever increasing demands on the construction of the spindle unit. The type of propulsion and bearing is the decisive component for providing the stated characteristics. Incorporating the drive directly into the spindle unit has successfully solved transmission problems at high speeds. In this way, the stress from the drive forces onto the spindle is

Both single-direction and alternating drives can in principle be used for integrated spindle units. Despite very good control properties, DC drives have known operational and technical drawbacks resulting from mechanical commutation devices—the commutator. For eliminating this deficiency, electronic commutation (Stromag and Bosch companies) is suitable. The use of synchronous frequency controlled drives is conditioned on the development of new hard magnetic materials [6]. In addition to the known Alnico alloys and hard ferrites, cobalt-based alloys characterized by high permanent induction (0.8–1 T) and high density are being developed, while the demagnetization curve is almost straight. An Italian company Polymotor is producing ring drives for integrated spindle units on a base of SmCO5 alloy. In an effort to reduce the consumption of rare earths and hence the cost of permanent materials, materials that do not contain rare earth are being developed. Mn-Al-C alloys are well known, as are materials containing CO, Cr,

At the present time, the majority of manufacturers of integrated drive spindle

For securing the drive parameters, it is necessary to choose a suitable frequency shifter, which processes the frequency of the 50 Hz network with an output frequency of up to 3000 Hz. They are thyristors or transistors with sinusoidal output. The main advantage of static converters compared to rotary converters is in

units use asynchronic frequency controlled drives due to their advantages

eliminated and its accuracy is increased (**Figure 15**).

(**Figure 14b**) [5].

*Machine Tools - Design, Research, Application*

**7. Spindle motor**

and Fe.

(**Table 2**).

**Figure 15.**

**54**

*Electric spindle motors (SIEMENS).*

*Comparison of lubrication methods for spindle bearings [6].*

continuous speed change control. Acceleration and braking work in a very short time without thermal load on the engine. There is no slip during braking, which is very advantageous for precise positioning of the spindle.

#### **8. Peripheral**

#### **8.1 Clamping system**

High-speed machining is associated with the development of new cutting materials such as cutting ceramics, synthetic polycrystalline diamond, and cubic boron nitride. In addition to the development of cutting materials with the new

physico-mechanical and chemical properties, increased attention must also be paid to the optimization of machine geometry with regard to chip removal at high machined material volumes. It will be necessary to design new holder and clamper constructions in light of the frequency of revolution, rigidity, and the flow of cooling liquids.

In addition to the demands that are placed on clamping systems used in high-speed spindle units are the following constructional and technological requirements [15, 16]:


Interfaces are used for HSC machining centers: steep taper ISO, SK, BIG PLUS (taper 7:24) and especially short taper HSK (taper 1:10), Kennametal/Widia KMTS KM4X.

Clamping of the tool holder in the spindle cavity is usually done by pulling it in by means of restressed disc springs (**Figure 16**). The release is then a hydraulic cylinder (**Figure 17**). The advantage of the HSK type for high speed is that the centrifugal forces cause the collet to open, which rests on the internal cavity surface of the shank (**Figure 18**). Rotary turrets replace tools in less than 1 second and accuracy positioning is max. 3 μm.

Since HSC technology uses around 50,000 rpm, tools must have radial runout max. 0.003 mm and with interchangeable cutting plates (VRP) max. 0.01 mm. All tools used must be perfectly balanced.

In HSC technology, the following are most commonly used as tool holders:

The thermal clamp allows quick clamping and unclamping of tools from the fast cutting steel, including sintered carbide. Tools are exchanged with a high-frequency generator that quickly warms up the tool holder and releases it tool. The following functions are used for the correct function of the tool: monitoring the tool holder contact in the spindle cavity, checking the temperature and force of the clamping system, checking the position of the clamping cylinder and the gripper, as well as

In the case of a hydroplastic clamp, the replacement is carried out using a hydraulic pump that squeezes the holder. Here, Pascal's law on the spread of uniform pressure is used, which ensures even clamping of the tool in the holder.

• the rigidity of the clamping ensures high quality of the machined surface;

checking the suction and temperature.

*End of spindle for clamping through the clamping shank [8].*

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

*Unsuitable and suitable clamping systems for high-speed spindles [DMG/Mori].*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

**Figure 17.**

**Figure 18.**

Advantages of these clamps:

• rapid shrinkage and release of the holder;

• circumferential runout less than 3 μm; and

• good bending and radial stiffness;

• clamping tools with shank h6;

• use at maximum speed.

**57**


**Figure 16.** *Holder and clamper constructions (GMN).*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Figure 17.** *End of spindle for clamping through the clamping shank [8].*

**Figure 18.**

physico-mechanical and chemical properties, increased attention must also be paid to the optimization of machine geometry with regard to chip removal at high machined material volumes. It will be necessary to design new holder and clamper constructions in light of the frequency of revolution, rigidity, and the flow of

In addition to the demands that are placed on clamping systems used in high-speed spindle units are the following constructional and technological

Interfaces are used for HSC machining centers: steep taper ISO, SK, BIG PLUS (taper 7:24) and especially short taper HSK (taper 1:10), Kennametal/Widia KMTS

Clamping of the tool holder in the spindle cavity is usually done by pulling it in by means of restressed disc springs (**Figure 16**). The release is then a hydraulic cylinder (**Figure 17**). The advantage of the HSK type for high speed is that the centrifugal forces cause the collet to open, which rests on the internal cavity surface of the shank (**Figure 18**). Rotary turrets replace tools in less than 1 second and

Since HSC technology uses around 50,000 rpm, tools must have radial runout max. 0.003 mm and with interchangeable cutting plates (VRP) max. 0.01 mm. All

In HSC technology, the following are most commonly used as tool holders:

a. small clamp dimensions limited by spindle dimensions;

c. balancing, providing resistance to high frequencies; and

b. low weight, ensuring low centrifugal forces;

d. quick automatic tool or work piece exchange.

accuracy positioning is max. 3 μm.

tools used must be perfectly balanced.

• thermal fixture; and

• hydroplastic clamp.

cooling liquids.

KM4X.

**Figure 16.**

**56**

*Holder and clamper constructions (GMN).*

requirements [15, 16]:

*Machine Tools - Design, Research, Application*

*Unsuitable and suitable clamping systems for high-speed spindles [DMG/Mori].*

The thermal clamp allows quick clamping and unclamping of tools from the fast cutting steel, including sintered carbide. Tools are exchanged with a high-frequency generator that quickly warms up the tool holder and releases it tool. The following functions are used for the correct function of the tool: monitoring the tool holder contact in the spindle cavity, checking the temperature and force of the clamping system, checking the position of the clamping cylinder and the gripper, as well as checking the suction and temperature.

In the case of a hydroplastic clamp, the replacement is carried out using a hydraulic pump that squeezes the holder. Here, Pascal's law on the spread of uniform pressure is used, which ensures even clamping of the tool in the holder.

Advantages of these clamps:


#### **8.2 Lubrication and cooling system**

In addition to the bearings themselves, the bearing parameters depend on the material and the quality of the surrounding parts, correct installation, and the choice of appropriate lubrication and cooling systems. These are lubrication and cooling of the contact point of the tool and work piece, lubrication and cooling of the bearings in the individual supports, and cooling of the motor and the headstock shell.

The correct choice of lubricant, method of lubrication, cooling liquid, method of cooling is as important for the proper operation of the bearing as the selection of the bearing and the design of the associated components. The methods used to lubricate and cooling the spindle bearings system at machine tools are shown in **Table 2**. Lubrication of bearings prolongs their life; it reduces the risk of their failures due to the mechanical damage at high speed; and it leads away generated heat. The lubrication method of spindle bearings at machine tools depends on the particular operation conditions.

The lubricating film thickness depends on the natural frequencies of rotation, operation temperature, and lubricant viscosity. In addition to the lubricant film thickness, it is necessary to assess the lubricant durability.

Grease for lubrication consists of 90% mineral oil or petroleum oil and 10% thickener. Lime soap, soda soap, lithium soap, or barium soap is used as the thickener. Grease durability depends on its quantity, sort, the bearing type, frequencies of rotation, and temperature in the assembled state. The bearings must be run in after their lubrication, and after a certain time period, they must be again lubricated. At running in, it is also necessary to take into account that grease can be well distributed on the whole bearing, which results in equalizing of temperatures generated by mechanic losses [6].

If the big accuracy is required at the spindle run, it is necessary to reduce heat. Passive friction moments that change to heat are influenced by the selected lubrication way and by the bearing design. The total passive friction moment is given:

$$M = M\_0 + M\_1 \quad \text{[N.mm]},\tag{20}$$

• oil-air lubrication—the oil is conveyed to the bearing in droplets by

*Components and peripheral devices used by selected manufacturers of electric spindles.*

controlled; and

**Table 3.**

**Producer Performance**

**range [kW]**

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Revolutions range [min<sup>1</sup>**

ENIMS 6.5 48–5200 Oil mist Air

IBAG 3–42 3000–80,000 Oil-air

GMN 3–40 9000–60,000 Oil mist

FAG 2.5–20 20,000–45,000 Oil-jet minim.

SKF 5.5–16 10,000–30,000 Oil mist

**]**

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

OMLAT 4.5–48.5 5000–40,000 Oil mist grease Air AC Mi, Dr., Gr

SZM 10–15 20,000–75,000 Oil-jet grease Air AC Mi, Gr ITW 15 22,000–36,000 Oil mist Air AC Mi, Gr

MODIGS 1.4 70–2160 Grease Liquid DC Gr, Mi FORTUNA 0.45–15 12,000–18,000 Oil mist Liquid AC Gr, Dr., Mi SETKO 3.7 400–10,000 Grease Liquid Fr, Dr PRECESI 0.17–6 7500–12,000 Oil mist Liquid AC Fr, Dr., Gr *Machine units with AC integrated drive, DC, direct drive; Tu, turning; Mi, milling; Dr, drilling; Gr, grinding.*

grease

Oil-jet grease

amount

Oil-air

**Lubrication Cooling Drive Technological**

liquid

Air liquid **operations**

AC Tu

AC Mi, Dr

Liquid AC Mi, Dr., Gr

Liquid AC Gr, Dr., Mi

Liquid AC Gr, Mi

**9. Realized outputs**

**59**

oil-to-air heat exchanger.

manufacturers of electric spindles (**Table 3**).

compressed air. The droplet size and the intervals between two droplets are

• Oil-jet lubrication (cooling lubrication)—considerable amounts of oil are carried through the bearing by injection, the frictional heat generated in the bearing is dissipated. The cooling of the oil is achieved, for example, with an

**Table 2** describes various lubrication technologies and **Table 3** gives an overview of the individual components and peripheral devices used by selected

tool headstocks are increasing. The headstock of a machine tool is now a

experience. For our headstock design, we have developed:

The spindle unit is determined by the structural parameters of the machine tool. In accordance with the growing requirements for production and precision of machine tools, the requirements for the design and technical execution of machine

mechatronic, highly sophisticated system in which internal systems with external peripherals must interact. The design, research and development of new types of headstocks is not possible today without high-quality computing and simulation software, high-performance computing, testing equipment, and the necessary

where *M0* is the friction moment dependent on the bearing design; and

*M1* is the friction moment dependent on loading (reaction).

The friction moment given by the bearing design and by the lubrication way is as follows:

*<sup>M</sup>*<sup>0</sup> <sup>¼</sup> *<sup>f</sup>* <sup>0</sup>*:*10�<sup>7</sup> *:*ð*ν:n*Þ 2*=*3 *:ds*<sup>3</sup> ½N*:*mm�, (21)

where

*f0* is the coefficient given by the bearing design (0.7–12); *ν* is the operation viscosity of oil or grease [mm<sup>2</sup> .s�<sup>1</sup> ]; *n* is the frequency of spindle rotation [min�<sup>1</sup> ]; and

*ds* is the mean spindle diameter [mm].

Lubrication by oil is used mainly in those cases where operation frequencies of rotation also require removal of generated heat from the bearing. At lubrication of the precise spindle bearings, it is necessary to use a small oil quantity to reach the highquality bearing lubrication. The most widely used lubricating methods are:

• oil mist lubrication—the oil mist is produced in an atomizer and conveyed to the bearings by an air current. The air current also serves to cool the bearings and the slightly higher pressure prevents contamination from penetration;


*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

#### **Table 3.**

**8.2 Lubrication and cooling system**

*Machine Tools - Design, Research, Application*

headstock shell.

operation conditions.

erated by mechanic losses [6].

follows:

**58**

where

In addition to the bearings themselves, the bearing parameters depend on the material and the quality of the surrounding parts, correct installation, and the choice of appropriate lubrication and cooling systems. These are lubrication and cooling of the contact point of the tool and work piece, lubrication and cooling of

The correct choice of lubricant, method of lubrication, cooling liquid, method of cooling is as important for the proper operation of the bearing as the selection of the bearing and the design of the associated components. The methods used to lubricate and cooling the spindle bearings system at machine tools are shown in **Table 2**. Lubrication of bearings prolongs their life; it reduces the risk of their failures due to the mechanical damage at high speed; and it leads away generated heat. The lubrication method of spindle bearings at machine tools depends on the particular

The lubricating film thickness depends on the natural frequencies of rotation, operation temperature, and lubricant viscosity. In addition to the lubricant film

Grease for lubrication consists of 90% mineral oil or petroleum oil and 10% thickener. Lime soap, soda soap, lithium soap, or barium soap is used as the thickener. Grease durability depends on its quantity, sort, the bearing type, frequencies of rotation, and temperature in the assembled state. The bearings must be run in after their lubrication, and after a certain time period, they must be again lubricated. At running in, it is also necessary to take into account that grease can be well distributed on the whole bearing, which results in equalizing of temperatures gen-

If the big accuracy is required at the spindle run, it is necessary to reduce heat. Passive friction moments that change to heat are influenced by the selected lubrication way and by the bearing design. The total passive friction moment is given:

The friction moment given by the bearing design and by the lubrication way is as

*:*ð*ν:n*Þ 2*=*3

Lubrication by oil is used mainly in those cases where operation frequencies of rotation also require removal of generated heat from the bearing. At lubrication of the precise spindle bearings, it is necessary to use a small oil quantity to reach the high-

• oil mist lubrication—the oil mist is produced in an atomizer and conveyed to the bearings by an air current. The air current also serves to cool the bearings and the slightly higher pressure prevents contamination from penetration;

quality bearing lubrication. The most widely used lubricating methods are:

where *M0* is the friction moment dependent on the bearing design; and

*M1* is the friction moment dependent on loading (reaction).

*<sup>M</sup>*<sup>0</sup> <sup>¼</sup> *<sup>f</sup>* <sup>0</sup>*:*10�<sup>7</sup>

*f0* is the coefficient given by the bearing design (0.7–12);

*ν* is the operation viscosity of oil or grease [mm<sup>2</sup>

*n* is the frequency of spindle rotation [min�<sup>1</sup>

*ds* is the mean spindle diameter [mm].

*M* ¼ *M*<sup>0</sup> þ *M*<sup>1</sup> ½N*:*mm�, (20)

.s�<sup>1</sup> ];

]; and

*:ds*<sup>3</sup> ½N*:*mm�, (21)

the bearings in the individual supports, and cooling of the motor and the

thickness, it is necessary to assess the lubricant durability.

*Components and peripheral devices used by selected manufacturers of electric spindles.*


**Table 2** describes various lubrication technologies and **Table 3** gives an overview of the individual components and peripheral devices used by selected manufacturers of electric spindles (**Table 3**).

#### **9. Realized outputs**

The spindle unit is determined by the structural parameters of the machine tool. In accordance with the growing requirements for production and precision of machine tools, the requirements for the design and technical execution of machine tool headstocks are increasing. The headstock of a machine tool is now a mechatronic, highly sophisticated system in which internal systems with external peripherals must interact. The design, research and development of new types of headstocks is not possible today without high-quality computing and simulation software, high-performance computing, testing equipment, and the necessary experience. For our headstock design, we have developed:


The results of our work are designed more headstocks of machine tools. At our institute, we developed headstocks for CNC machine tools for the companies TOS Lipník and TOS Kuřim. The headstocks developed for SBL CNC lathes manufactured by the company Trens Trenčín deserve special attention [17]. The headstocks of the 300, 500, and 700 series developed at our workplace and the first lathes SBL was first time at the exhibition in Nitra 2000 and at the exhibition in Düseldorf 2004 presented. The SBL series lathes with the listed headstocks are still produced and are successful in the market.

stiffness, maximum speed, temperature, and running accuracy, are tested in our laboratories. Both the software and the experimental stand were developed at our

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

The technical level of fully automated flexible production systems has reached a degree at which accompanying working times and instruments are reduced to a minimum. Further increases in output are therefore possible by reducing the main

This is possible by increasing cutting speeds—high-speed machining. Research in the field of high-speed cutting shows that, along with the reduction of lead times, cutting accuracy, productivity and machined surface quality are significantly

In the chapter, requirements, characteristics, and development tendencies of the

The headstock is a determining structural node affected technological parameters machine tool. For high-speed machining, headstocks with built-in drive are

The results of the analysis showed that electromagnetic and rolling spindles are used to accommodate the spindles of high-speed headstocks. Exceptionally with lower rigidity requirements, an aero-static bearing can also be used. The most widely rolling bearings used machine tool spindle support are nodes—formed from radial ball bearings with angular contact. They are reliable enough, cost-effective and, given the wide range of combinations, they can optimally meet the contradictory requirements of stiffness and maximum speed. Hybrid ball bearings are used

In terms of drives, both single-direction and alternating drives can be used in the

principle for integrated spindle units. Despite very good control properties, DC

whole concept of construction of a machine, as well as construction nodes and elements of machine for high-speed cutting are described. With respect to the individual technological operations and the range and diversity of the required parameters, it is clean that at this time, it is not possible to design and universal machining unit—headstock. This requires a modular construction of the machining tool and individual peripheries that make possible a rapid change of the machining

unit with the required revolution and performance characteristics.

for the highest rotational speeds but are very expensive.

workplace.

**Figure 20.**

**10. Conclusion**

*Motor spindles for grinding machine tool [18].*

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

production times.

used "Electrospindles."

improved.

**61**

Well known is our design of high-speed headstock with two drives. The advantage of the original solution is the possibility of using a high torque moment at low revs, as well as the principle of achieving high resultant revolutions of a doublemounted spindle driven by two drives [11]. The headstock is applied to a wood lathe in the company Šustrik.

An example of a new functional model of an electric headstock for a grinding machine is shown **Figure 20** [18]. It is a design of a headstock designed on the basis of modular components of an AC motor (stator, rotor, and metering system) and compact control system of the IMB Indramat drive. The functional model is preferably used in our laboratories for ultrasonic grinding.

When designing all headstocks, we use the V-2.16 headstock application software. The technical parameters of the rolling bearing nodes, such as axial and radial

**Figure 19.**

*Laboratory for measuring: (a) testing equipment for measuring bearing nodes; and (b) test bench for testing functional models.*

#### *Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

**Figure 20.** *Motor spindles for grinding machine tool [18].*

stiffness, maximum speed, temperature, and running accuracy, are tested in our laboratories. Both the software and the experimental stand were developed at our workplace.

#### **10. Conclusion**

• special software that enables the calculation of the load, stiffness, and durability of rolling bearings used for the bearing of machine tool spindles [11–13]. Our methodology of calculation of bearing nodes associated from radial ball bearings angular contact is original. At the same time, the software enables to calculate the optimal distance of bearing supports with respect to overall maximum stiffness, running accuracy, and thermal expansion

expansion of the whole spindle bearing system; and

is carried out under different operating conditions.

produced and are successful in the market.

*Machine Tools - Design, Research, Application*

ably used in our laboratories for ultrasonic grinding.

in the company Šustrik.

**Figure 19.**

**60**

*functional models.*

Lipník and TOS Kuřim. The headstocks developed for SBL CNC lathes

according to the arrangement of bearings in individual nodes as well as thermal

• special testing equipment for measuring the accuracy of running, temperature, and stiffness of bearing nodes made of radial ball bearings with angular contact. The experimental bench (**Figure 19**) enables the determination of required parameters of nodes arrangement by up to 5 bearings [6, 11]. Testing

The results of our work are designed more headstocks of machine tools. At our institute, we developed headstocks for CNC machine tools for the companies TOS

Well known is our design of high-speed headstock with two drives. The advantage of the original solution is the possibility of using a high torque moment at low revs, as well as the principle of achieving high resultant revolutions of a doublemounted spindle driven by two drives [11]. The headstock is applied to a wood lathe

An example of a new functional model of an electric headstock for a grinding machine is shown **Figure 20** [18]. It is a design of a headstock designed on the basis of modular components of an AC motor (stator, rotor, and metering system) and compact control system of the IMB Indramat drive. The functional model is prefer-

When designing all headstocks, we use the V-2.16 headstock application software. The technical parameters of the rolling bearing nodes, such as axial and radial

*Laboratory for measuring: (a) testing equipment for measuring bearing nodes; and (b) test bench for testing*

manufactured by the company Trens Trenčín deserve special attention [17]. The headstocks of the 300, 500, and 700 series developed at our workplace and the first lathes SBL was first time at the exhibition in Nitra 2000 and at the exhibition in Düseldorf 2004 presented. The SBL series lathes with the listed headstocks are still

> The technical level of fully automated flexible production systems has reached a degree at which accompanying working times and instruments are reduced to a minimum. Further increases in output are therefore possible by reducing the main production times.

> This is possible by increasing cutting speeds—high-speed machining. Research in the field of high-speed cutting shows that, along with the reduction of lead times, cutting accuracy, productivity and machined surface quality are significantly improved.

> In the chapter, requirements, characteristics, and development tendencies of the whole concept of construction of a machine, as well as construction nodes and elements of machine for high-speed cutting are described. With respect to the individual technological operations and the range and diversity of the required parameters, it is clean that at this time, it is not possible to design and universal machining unit—headstock. This requires a modular construction of the machining tool and individual peripheries that make possible a rapid change of the machining unit with the required revolution and performance characteristics.

The headstock is a determining structural node affected technological parameters machine tool. For high-speed machining, headstocks with built-in drive are used "Electrospindles."

The results of the analysis showed that electromagnetic and rolling spindles are used to accommodate the spindles of high-speed headstocks. Exceptionally with lower rigidity requirements, an aero-static bearing can also be used. The most widely rolling bearings used machine tool spindle support are nodes—formed from radial ball bearings with angular contact. They are reliable enough, cost-effective and, given the wide range of combinations, they can optimally meet the contradictory requirements of stiffness and maximum speed. Hybrid ball bearings are used for the highest rotational speeds but are very expensive.

In terms of drives, both single-direction and alternating drives can be used in the principle for integrated spindle units. Despite very good control properties, DC

drives have known operational and technical drawbacks resulting from commutation devices. They are used less than AC drives. From the point of view of lubrication, the oil-air system is used for the highest rotational frequencies, while grease lubrication is still used for the lowest rotational requirements.

**References**

[1] Schmockel D, Arnold W, Scherer J. Hochgeschwindigketsfräsen von Aluminium legierungen. VDI Zeitschrift. 1980;**122**(19):243-245

*DOI: http://dx.doi.org/10.5772/intechopen.92713*

*Headstock for High Speed Machining - From Machining Analysis to Structural Design*

Evaluation of Bearings. Novi Sad, Croatia: Intech Prepress; 2012. pp. 49-92, 240. ISBN: 978-953-51-0786-6

[12] Šooš Ľ. New methodology calculations of radial stiffness nodal points spindle machine tool. In:

2010. Hunedoara: Faculty of

International symposium on Advanced Engineering & Applied Management— 40th Anniversary in Higher Education: Romania/Hunedoara/4–5 November

Engineering Hunedoara; 2010. pp. III-99-III-104. ISBN: 978-973-0-09340-7

[13] Šooš Ľ. Approximate methodology calculations of stiffness nodal points. World Academy of Science, Engineering and Technology. 2011;**7**(80):1390-1395

[14] US Patent: US 6,422,757 B1 Active piezoelectric spindle bearing preload adjustment mechanism. July 23 2002

[15] Marek J et al. Designing of CNC Machine Tools. Praha: MM Publishing, s. r. o.; 2015. p. 727 s. ISBN: 978-80-260-

[16] Available from: http://www.gmn/

[17] Šooš Ľ. Spindle–Housing system SBL 500 CNC. Eksploatacja i Niezawodnošč = Maintenance and reliability. 2008;**2**:

[18] Greguš Kolár J. High speed motor spindles for grinding (in Slovak). Bratislava: FME STU; 2015. p. 67

8637-6

53-56

en/downloads.html

[2] Schulz H, Scherer J. Aktueller stnd des verbundforschurgsprojekts, Hochgeschwindigkeitsfräsen. Die

[3] Pasko R, Przybylski L, Slodski B. High speed machining (HSM)—The effective way of modern cutting. In: International Workshop CA Systems and Technologies. pp. 72-79. [Accessed:

[4] König W. Technologische Aspekte der Hochgeschwindigkeitzerspannung. Vorträg ansläβlich einer HGF—Tagung 17–18.4.1980. Eigenverlag der TH

[5] Available from: https://www.google. com/search?q=Skf+Motor+spindles

[7] Lee D, Sin H, Sun N. Manufacturing of a graphite epoxy composite spindle for a machine tool. Annals CIRP. 1985;

[8] Demeč P. Accuracy of Machine Tools and Its Mathematic Modelling. 1st ed. Košice, Vienala: Technical University in Košice; 2001. p. 146. ISBN: 80-7099-

[9] Available from: https://www. magnetic.waukbearing.com

[10] Available from: http://www.ibag.

[11] Šooš Ľ. Chapter: Radial ball bearings with angular contact in machine tools. In: Sehgal R, editor. Performance

[6] Marek J et al. Designing of CNC Machine Tools. Praha: MM Publishing, s. r. o; 2010. p. 419 s. ISBN: 978-80\_254–

Maschine. 1987;**10**:14-18

24 April 2003]

Aachen; 1980

7980-3

**34**:365-369

620-X (in Slovak)

ch/en/downloads.html

**63**

The headstock is a complicated mechatronic node with a system of internal elements and external peripherals. Designers must, in addition to complicated computer systems, perfectly master the demands placed on the headstock and the interoperability of individual elements and peripherals. New non-traditional materials (SI3N4, SmCO5 alloy) as well as progressive design technologies and design solutions are used to achieve the best technical parameters of these headstocks. At the end of the chapter, we present our results and experience in the design of headstocks of machine tools.

#### **Acknowledgements**

The research presented in this paper is an outcome of the project No. APVV-16-0476 "Research and development of the progressive design of the high speed rotor mounting in spinning machine" funded by the Slovak Research and Development Agency.

#### **Author details**

Ľubomír Šooš Institute of Production Systems, Environmental Technology and Quality Management of the Faculty of Mechanical Engineering of STU in Bratislava, Bratislava, Slovakia

\*Address all correspondence to: lubomir.soos@stuba.sk

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

*Headstock for High Speed Machining - From Machining Analysis to Structural Design DOI: http://dx.doi.org/10.5772/intechopen.92713*

#### **References**

drives have known operational and technical drawbacks resulting from commutation devices. They are used less than AC drives. From the point of view of lubrication, the oil-air system is used for the highest rotational frequencies, while grease

The headstock is a complicated mechatronic node with a system of internal elements and external peripherals. Designers must, in addition to complicated computer systems, perfectly master the demands placed on the headstock and the interoperability of individual elements and peripherals. New non-traditional materials (SI3N4, SmCO5 alloy) as well as progressive design technologies and design solutions are used to achieve the best technical parameters of these headstocks. At the end of the chapter, we present our results and experience in the design of

The research presented in this paper is an outcome of the project No. APVV-16-0476 "Research and development of the progressive design of the high speed rotor mounting in spinning machine" funded by the Slovak Research and

Institute of Production Systems, Environmental Technology and Quality Management of the Faculty of Mechanical Engineering of STU in Bratislava,

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: lubomir.soos@stuba.sk

provided the original work is properly cited.

lubrication is still used for the lowest rotational requirements.

headstocks of machine tools.

*Machine Tools - Design, Research, Application*

**Acknowledgements**

Development Agency.

**Author details**

Bratislava, Slovakia

Ľubomír Šooš

**62**

[1] Schmockel D, Arnold W, Scherer J. Hochgeschwindigketsfräsen von Aluminium legierungen. VDI Zeitschrift. 1980;**122**(19):243-245

[2] Schulz H, Scherer J. Aktueller stnd des verbundforschurgsprojekts, Hochgeschwindigkeitsfräsen. Die Maschine. 1987;**10**:14-18

[3] Pasko R, Przybylski L, Slodski B. High speed machining (HSM)—The effective way of modern cutting. In: International Workshop CA Systems and Technologies. pp. 72-79. [Accessed: 24 April 2003]

[4] König W. Technologische Aspekte der Hochgeschwindigkeitzerspannung. Vorträg ansläβlich einer HGF—Tagung 17–18.4.1980. Eigenverlag der TH Aachen; 1980

[5] Available from: https://www.google. com/search?q=Skf+Motor+spindles

[6] Marek J et al. Designing of CNC Machine Tools. Praha: MM Publishing, s. r. o; 2010. p. 419 s. ISBN: 978-80\_254– 7980-3

[7] Lee D, Sin H, Sun N. Manufacturing of a graphite epoxy composite spindle for a machine tool. Annals CIRP. 1985; **34**:365-369

[8] Demeč P. Accuracy of Machine Tools and Its Mathematic Modelling. 1st ed. Košice, Vienala: Technical University in Košice; 2001. p. 146. ISBN: 80-7099- 620-X (in Slovak)

[9] Available from: https://www. magnetic.waukbearing.com

[10] Available from: http://www.ibag. ch/en/downloads.html

[11] Šooš Ľ. Chapter: Radial ball bearings with angular contact in machine tools. In: Sehgal R, editor. Performance

Evaluation of Bearings. Novi Sad, Croatia: Intech Prepress; 2012. pp. 49-92, 240. ISBN: 978-953-51-0786-6

[12] Šooš Ľ. New methodology calculations of radial stiffness nodal points spindle machine tool. In: International symposium on Advanced Engineering & Applied Management— 40th Anniversary in Higher Education: Romania/Hunedoara/4–5 November 2010. Hunedoara: Faculty of Engineering Hunedoara; 2010. pp. III-99-III-104. ISBN: 978-973-0-09340-7

[13] Šooš Ľ. Approximate methodology calculations of stiffness nodal points. World Academy of Science, Engineering and Technology. 2011;**7**(80):1390-1395

[14] US Patent: US 6,422,757 B1 Active piezoelectric spindle bearing preload adjustment mechanism. July 23 2002

[15] Marek J et al. Designing of CNC Machine Tools. Praha: MM Publishing, s. r. o.; 2015. p. 727 s. ISBN: 978-80-260- 8637-6

[16] Available from: http://www.gmn/ en/downloads.html

[17] Šooš Ľ. Spindle–Housing system SBL 500 CNC. Eksploatacja i Niezawodnošč = Maintenance and reliability. 2008;**2**: 53-56

[18] Greguš Kolár J. High speed motor spindles for grinding (in Slovak). Bratislava: FME STU; 2015. p. 67

Section 2

Research and Development

**65**

Section 2
