Introductory Chapter: Current Trends in Micromachining Technology

*Ivanka Stanimirović and Zdravko Stanimirović*

### **1. Introduction**

Originating in the mid-1900s, micromachining became a cutting-edge method that is changing the way we think about small-scale component fabrication. Micromachining usually refers to a precise micrometer scale subtractive manufacturing processes that are essential for producing highly precise micro components, which are needed in the electronics, medical, aerospace and other growing industries. Fabrication capabilities are constantly being improved by the meticulous design of tools and processes that can handle dimensions and tolerances that traditional machining cannot handle. The industry's constant search for increasingly accurate and finer techniques is reflected in the progression from basic mechanical micromachining to more complex methods.

Through its special abilities and applications, micromachining sets itself apart from traditional machining. To meet the needs of a wide range of industries, micromachining can be used on a wider range of materials, such as polymers, metals and composites. Far beyond what is possible with conventional machining, micromachining produces features and tolerances on a micrometer scale. In these processes, much smaller and more precise micro tools are used, which frequently call for specific handling and setup. Precision that micromachining can provide is crucial for industries that require high levels of accuracy, such as semiconductor manufacturing and medical device fabrication.

This chapter provides a brief summary of the materials and techniques currently used in micromachining, as well as an overview of the main applications, challenges, and advancements in micromachining technology. It also provides a brief analysis of the current micromachining market.

## **2. Micromachining techniques and materials**

The field's precision and versatility are greatly enhanced by the multitude of techniques [1–13] that are currently employed in micromachining, each well-suited to particular material and application. These techniques can be grouped into five major categories:

1.Mechanical micromachining [1–6]– a method used in precision engineering to create small, detailed features on workpieces. It is crucial for high-precision industries like electronics and medicine because it allows realization of miniature parts with outstanding precision and surface qualities.


Each of these micromachining categories includes several key techniques presented in **Table 1**.

Micromachining techniques can handle fine micron scale features with extreme precision. Depending on the technique and material used, as well as on the component complexity, general tolerances are typically in the ± (0.001–0.005) mm range. Tolerances for high precision can be as low as ±0.0001 mm. Typical method-specific tolerances are presented in **Figure 1**. Micromachining tolerances [14] depend on multiple factors: material properties, tooling quality and precision, workpiece stability, machining environment, etc.

The precision and quality of the micromachined component are affected by how different materials react to micromachining techniques. Commonly used materials are metals (stainless steel, copper, titanium, etc.), ceramics (alumina, silicon carbide, etc.), polymers (ABS, Polycarbonate, etc.) and composites (Carbon Fiber Reinforced Plastics, etc.) [15–19]. Stainless steel, favored for its strength, durability and corrosion resistance, is one of the most popular materials used in micromachining [15]. Stainless steel is commonly used in medical applications for realization of various medical devices, implants and surgical instruments. Although highly-priced and difficult to machine, titanium is a valuable asset for micromachining [16]. It is light, heat and corrosion-resistant, biocompatible and inert and has a high strength-to-weight ratio. For these reasons, titanium can be used in a variety of applications ranging from medical to aerospace. Another metal suitable for precision machining, highly regarded for its natural corrosion resistance, thermal and electrical conductivity, durability and versatility, is copper. It is commonly used in electronics and cooling systems. Cost-efficient, nonconductive, nonmetal materials for micromachining are polymers [17]. Because of their inertness and adaptable properties, micromachined parts based on polymer materials are used in various industries ranging from medical to automotive. Micromachined alumina and silicon carbide parts are used in various industrial applications because of their thermal and chemical stability, dielectric strength, hardness, dimensional stability, ability to withstand harsh environments, etc. [18]. Micromachined ceramics allow fine feature formation without occurrence of heat-affected zones or microcracks while maintaining high cut quality. Carbon fiber-reinforced plastic (CFRP) materials are being recognized for their lightweight properties and high strength-to-weight ratio [19]. Micromachined CFRP parts are


*Micro-LBM—Micro Laser Beam Machining, Micro-EBM—Micro Electron Beam Machining, Micro-AJM—Micro Abrasive Jet Machining, Micro-FIB—Micro Focused Ion Beam Machining.*

#### **Table 1.** *Micromachining techniques.*

**Figure 1.** *Method-specific tolerances.*

used in advanced engineering applications like electronics, aeronautics, automobiles, etc. Lately, micromachined glass has become of interest in the medical, aerospace, or microelectronic industries because micromachined glass parts can be manufactured with great accuracy while staying strong, are reusable and can be easily cleaned [19].

### **3. Primary micromachining applications**

Contemporary micromachining techniques offer high precision and ability to work with diverse materials. They drive innovation and efficiency in a broad range of industries. Some of primary micromachining applications are in electronics, optics, telecommunications, medicine, MEMS, aerospace and automotive industries etc. (**Figure 2**). Micromachining is fundamental in microelectromechanical system (MEMS) manufacturing. MEMS microscale devices, actuators and sensors are being used in medical, electronics and automotive industries. In electronics, micromachining is essential in realization of miniature electronic devices such as microprocessors and microcontrollers. Electronic devices often require sub-micron range tolerances. Micromachined components for communication devices, such as micro-scale antennas and fiber-optic connectors, are essential in the field of telecommunications. Optical devices require precise geometries and excellent surface finishes. Performances of small-scale mirrors, lenses and other optical devices depend on high-precision micromachining techniques. Medical applications demand precise, complex, safe and effective micromachined implants and tools for surgical, diagnostic and other medical purposes. They require great precision, with tight tolerances, lower than ±0.002 mm. The aerospace industry requires miniature high-precision aerospace components of outstanding reliability and performance, e.g. fuel injectors, sensors, control mechanisms, etc. The automotive industry uses micromachining for creating small components for electric vehicles automotive sensors, fuel injection nozzles, etc. It can be concluded that micromachining's capacity to deal with diverse materials and produce intricate micro-scale geometries makes it a leader in the development and prototyping of new devices in a number of industries, including nanotechnology and new material creation.

*Introductory Chapter: Current Trends in Micromachining Technology DOI: http://dx.doi.org/10.5772/intechopen.114841*
