The combination of all technical and associated administrative actions intended to retain an item in, or restore it to, a state in which it can perform its required function. This required function may be defined as a stated condition.
The key words to note in this definition identify the fact that there are both technical and administrative actions involved in maintaining an item of equipment in a satisfactory and functional state. Thus maintenance actions can be split into two distinct categories, that is those without a logical and predetermined administrative plan, and those organized with forethought to produce a logical and predetermined administrative plan of action.
The second group contains many different approaches, one of which condition-based maintenance, each category has its strengths and weaknesses, accordingly both will be reviewed, so that the techniques of condition-based maintenance can be understood within their proper context. Before the review is undertaken however, it is essential to explain why maintenance is now being recognized as an important activity within a manufacturing concern, and one which significantly impacts the competitiveness and profitability of a company .
The introduction of highly automated equipment such as flexible manufacturing systems or cells (FMS/FMC) to the discrete batch manufacturing sector of UK industry, has produced a realization tat downtime, and its associated lost production, is a great deal higher and more costly on this type of equipment than with the more traditional, non- integrated manufacturing plant which it replace, indeed when one considers the cost.
It involves:
- DETECTION - spotting at sufficiently early stage an adverse change in the operating conditions of a component or a subsystem.
- DIAGNOSIS - Determination of the cause of causes of the adverse change.
- PROGNOSIS - Estimation of a subsequent future state of the system or component and the time scale and lastly.
- CURE - maintenance planning and execution.
Involved in the failure and repair of this type id hi-tech equipment, it is easy to understand why system availability, reliability and maintainability are now regarded as being of first importance to manufacturing managers.