Various approaches to maintenance are explained: maintenance after failure (breakdown maintenance), preventive maintenance, on-condition maintenance, reliability centred maintenance (RCM), the use of technical diagnostics.
- preventive maintenance
- on-condition maintenance
- reliability centred maintenance (RCM)
- technical diagnostics
The operational reliability and service life of machines, vehicles, various appliances, bridges, and many other long-life objects are strongly influenced by
Maintenance is related to the kinds of objects and failures, and its techniques and strategies have been developed along with the development of technology. Historically first was the
During the first half of the 20th century, substantial changes have occurred. The machines, vehicles and other objects became more complex, with failures from various reasons. The number of failures grew, the more so that some products, such as cars, were produced in large series in production lines. The consequence of a failure of a machine in such line was the stopping of the whole line, and the losses caused by this break became much bigger. Also a failure of a complex and expensive object (e.g. a locomotive, a big ship, or an aircraft) meant big losses. Many of these failures were due to wear or fatigue and occurred after a certain time of operation. Thanks to the understanding of these processes, it became possible to predict approximately the time to failure or to a significant degree of wear in some kinds of items (bearings, cylinders and piston rings, sealing, and valves), or the time to the critical loss of efficiency of oil or air filters, etc. All this has led to the change of the maintenance philosophy. Gradually, the so-called
In complex systems consisting of many components, failures occur from various reasons, in irregular intervals, and the failures of the system usually occur due to other reasons than the fatigue of key components. During this useful period of the life, the failure rate of the system is approximately constant and the time between failures has exponential distribution (cf. Chapter 4). The maintenance according to a fixed plan then loses any substantiation.
Another drawback of preventive maintenance is that the replacement of components in fix intervals can be too early for some of them, which is uneconomical, and too late for some others, which can mean worse efficiency of operation or a higher risk of failure. As the methods for ascertaining the technical condition become gradually better, an approach based on the use of
In machinery, chemical, and some other industries, maintenance has become a very important branch. However, the related costs are high. Ways are therefore sought to reduce them. Currently, the so-called
Maintenance is a wide topic that goes much beyond this concise book. The reader is referred to the literature, such as [1 - 3].
Moubray J. RCM II - Reliability-centered Maintenance. London: Butterworth-Heinemann; 1997. 426 p.
Ireson W G, Coombs C F Jr, Moss R Y. Handbook of reliability engineering and management. 2nd ed. New York: McGraw-Hill; 1996. 816 p.
Legát V et al. Management and engineering of maintenance (in Czech: Management a inženýrství údržby). Kamil Mařík Professional Publishing, 2013. 570 p.