**3. Maintenance systems**

The maintenance kinds include activities by which the maintenance is conducted. The maintenance kinds are as follows:

1.Running maintenance consists of

• cleaning,


2. Inspection activities are:

	- small repair,
	- medium repair,
	- general overhaul.
	- modernization,
	- reconstruction,
	- module replacement (exchange),
	- upgrading,
	- machine replacement.

**Running maintenance** means a regular care of objects. It has a prevention character. For this activity, the terms care-upkeeping are used.

It is a running, regular machines, and equipment maintenance. By this maintenance a premature wear and defects can be prevented. The running maintenance includes cleaning, set up of machines and equipment, tightening of loosened connections, refilling of recording (writing) parts of measuring and recording apparatuses. But it is the measurement which has the greatest significance in the whole maintenance process. To the maintenance also small repairs belong, which are conducted during the maintenance. The difference between maintenance and repairs lies also in the fact which workers are conducting them. Whereas specialists conduct the repairs, especially operatives who are also appointed with other duties conduct the maintenance. The operatives of machines and equipment conduct the running maintenance.

**Inspection activity** in maintenance presents a revision and control activity regarding the condition, maintenance and repair of machines and equipment within the framework of maintenance. From the point of view of a professional, the inspection concerns all kinds and ways of maintenance. It is appropriate to create professional inspection departments (e.g., machinery, electrical, construction, etc.) and to record the results of these controls and revisions into inspection books.

*Perspective Chapter: Analysis of the Operational Reliability of Forest Equipment DOI: http://dx.doi.org/10.5772/intechopen.107402*

The monitoring of defects belongs to the important duties of an inspection. The inspection is dependent on the maintenance organization. It is not uniform, and the organizational incorporation is not uniform.

The inspection work content results from its basic objective.

**Diagnostics** presents the detecting of the object condition, e.g., its monitoring and registration of magnitude values which define the condition and development of a subject [14].

By introducing the subject maintenance on the base of the diagnostics of their conditions it is necessary to solve the following tasks:


The diagnostics of a subject is conducted on the base of:


**Prophylaxis means** a regular control of the condition of electrical equipment, information technology appliances, instruments in medicine, etc.

**General Overhaul** represents the repair of the whole basic equipment. By the general overhaul, the effects of wear and damage are removed. The aim here is to renew the original.

Performance, technical properties, operational quality, and profitability of the basic equipment. It is of advantage to improve its properties based on the technological progress. This can be achieved through the modernization. The general overhaul must ensure that the basic equipment will be able to work until the next general overhaul. It is convenient to conduct the general overhauls in specialized shops. General overhauls belong to the biggest, most important but also most costly repairs.

**Medium repair** is a repair performance of a greater extent, in which a larger number of machine or equipment parts is replaced or repaired. The extent of a medium repair is determined on the base of inspection results and findings detected during small repairs. Medium repairs represent a significant activity in the operation. Their extent is large, and they are conducted often.

**Small repair** includes all remaining repair performances, the extent of which is smaller in comparison with medium repairs and general overhauls. Small repairs present a large number of repairs. A part of small repairs can be done during preventive inspections by workers who conduct an inspection.

Renovation of an Object.

An intensive technical development requires that during repairs (especially during general overhauls) not only the physical but also the moral wear of equipment be removed. The total dismantling of a machine is to be used for the removal of its technical obsolescence. In this way a modernization is conducted. It includes various


**Maintenance is set of activities to secure the determined operational state of an object by technical conditions, as well as to define and consider its actual state.**

#### **Table 2.**

*The characteristics of maintenance kinds [15].*

technical improvements of a machine, by which a higher performance can be achieved, easier handling (operation), higher precision, longer life, higher safety at work, mechanization of operational manipulation, etc [13].

The modernization as a sustainable process acting against the moral wear, becomes an organic component of a repair. In association with the modernization the term reconstruction is to be specified. A modernization can represent such an improvement, which changes its original character. A reconstruction is such a performance, by which the original character of the reconstructed object is (permanently) changed (e.g., when general purpose machines are adopted to a single purpose, special machines).

Current trend of machines and equipment development, new trends in IT- equipment maintenance, when the manufacture of a module in a large series production is cheaper than the repair of a faulty one and it results in module exchange or when the downtime due to the repair, and the loss due to this downtime, and repair costs are comparable with the value of a new module.

In IT, where the replacement of an original is enlarged by a new one which ensures the original function or extends it, is called upgrading. In case that any of this kind of activity does not put the object into an operable condition, or if the costs for its maintenance are inadequate, the exchange of the machine takes place (**Table 2**).

## **4. The objective of maintenance and repair function**

The basic function of the maintenance and repair activity is to ensure work capability of HIM and NIM in production. The significance of this function increases simultaneously with the increase of production technical level, and specially with the increase of automatic machines, lines, and integrated production processes.

The sum of work, the task of which is to secure the capability of machine and equipment operation, and their total effective running, is called maintenance-repair activity, sometimes only a maintenance. In a narrower sense, under this term we understand cleaning, lubrication.

and other regular protection of basic means prior to repair e.g., current maintenance. In a broader sense, under the term maintenance we understand any care of basic means, by which their working capability is ensured. Here belongs current maintenance of machines during operation, as well as all kinds of planned and nonplanned repairs, by which the consequences of wear are removed.

#### *Perspective Chapter: Analysis of the Operational Reliability of Forest Equipment DOI: http://dx.doi.org/10.5772/intechopen.107402*

In real life situation it is difficult to draw the exact border line between maintenance and repairs because these activities often overlap. During current maintenance small repairs are done, and vice versa, during repairs, sometimes current maintenance must be conducted.

Principally the removal of wear consequences is called repair. From the economic point of view, it is execution of additional work on the fixed assets, by which their wear is to be removed. The inner differentiation of maintenance-repair work is being derived from the level of functioning of the fixed assets (basic means). In trouble-free functioning the supervisory-inspection activity will be enough. It must avoid undesired conditions. If the functioning worsens, it is necessary to conduct repairs. According to their extent there are various degrees of maintenance/repair activities:

Current maintenance consists of cleaning, lubrication, inspection, and other pre-repair activity.

Small repair consists of such work as repair and replacement of smaller parts, which are subject to wear, replacement of sealing of taps, valves, cleaning and exchange of oil and cooling systems, oil cups, etc.

Medium repair is characterized by the fact, that during its execution the opening and inspection of all boxes and closed mechanisms is done, larger parts and aggregates are being repaired and replaced, the whole lubrication system is being flushed. According to circumstances machine slide ways are being repaired and the whole set-up of a machine is conducted, including precision checking. The medium repairs are conducted on the site, where the machines are installed. Only exceptionally they are conducted in repair shops, specially determined for repairs. In any case, after the medium repair a control protocol is written down, where there is the record of handing over the machine and the record on precision control results.

General overhaul (GO) presents the biggest repair performance in maintenance. In this kind of repair, the whole machine undergoes the repair, not just its parts. For this reason, it is being released from its base, it is disassembled to its individual parts and repaired in a special workshop. The extent and quality of GO must ensure that the machine will obtain the original technical properties and its planned life will be obtained. The machine or other fixed asset undergoes a test according to standards after the general overhaul and is handed over to operation by means of a protocol.

The intensive technical development requires still more that in repairs (specially in general overhauls) not only physical, but also moral wear is removed. The complete disassembly of a machine must be also used for eliminating its technical obsolescence. In such a way modernization takes place. It includes various technical improvements of the machine by which its higher performance, easier handling (operation), higher precision, longer life, improved safety at work, mechanization of operation manipulation, etc. can be achieved. In such a way the modernization, as a continuous process acting against the moral wear, becomes an organic part of repairs.

In association with the modernization the term reconstruction must be specified. Modernization can represent such a machine improvement which does not change its original character. Reconstruction, on the other side, presents such a performance, by which the original character of the reconstructed machine has been changed permanently (e.g., when multi-purpose machines are adapted to single-purpose, special machines) (**Tables 3** and **4**).


#### **Table 3.**

*The objective of maintenance and repair function [16].*


#### **Table 4.**

*Organizational maintenance forms [17].*

Decentralized organization form results from the fact that workers are assigned on the base of their qualification and work-legal relations to individual lower organizational units, e.g., plant. With consequent implementation of this form of maintenance the incorporation of maintenance operation into the structure of each production unit is assumed. This unit works independently and is linked directly to the organizational structure of the production unit. The workers have been specialized in the equipment of the given operation. This fact is of advantage specially both at work within current maintenance, as well as with equipment inspection.

Integrated organizational form – is based on the supposition that service workers (service men) conduct, beside the maintenance activities, also current operational work. For this work universal specialists with broad knowledge and skills are required.
