Condition Based Maintenance is a concept based on the slightly amended premise that ‘if it ain’t broke don’t fix it’.  The amendment might read ‘if it ain’t broke and you can prove it don’t fix it.’

Condition based Maintenance or CBM; properly implemented (and it rarely is) moves away from traditional maintenance scheduling which has always been based on calendar, hours run or similar time related usage measures.   CBM will still generate time related maintenance tasks but these will be related to tangible measures of the machine’s condition, ideally be non intrusive (not taking the machine apart) and relate to known failure modes.  

Example… motor gearboxes are prone to teeth wearing.  Route Cause Analysis or a similar investigative technique may determine that this is due to deterioration of the lubricating oil.  A suitable condition based maintenance task would then be taking oil samples for specialist analysis every 3 months.  The maintenance task would therefore be the oil sampling with follow up only being initiated by adverse reports on the condition of the oil.

In the example of the gearbox it will be obvious that there are several alternatives to the condition based maintenance task suggested.  Make no mistake CBM can be expensive and must therefore be justified by the maintenance professional on a cost/benefit analysis.  On small units it may be more economic to revert to planned preventive maintenance such as changing the oil and filter at set periods.

Main failings of Condition Based Maintenance

Inappropriately applied – condition based maintenance can only be used on machines that show deterioration in some way and over a time period that allows a maintenance response before they fail.  A gearbox is a good example where we might expect vibration, overheating, noise as signs of deterioration before it grinds to a halt.  A light bulb although it has failure characteristics is over such a short timescale that it is an impractical subject for condition based maintenance (although a lighting system may be suitable).  

The time between deterioration setting in and failure is known as the p-f interval.

Not focused – when CBM is implemented without cost/benefit or risk based assessment of the implications of the loss of the machine/function to which it contributes – the gearbox example gave what  the majority of the time would be an acceptable and economic alternative (change oil and filter periodically regardless of condition).

CSA have implemented cost effective maintenance improvement programs for many leading manufacturers. For a no obligation initial chat and an indication as to cost; please complete the form and we will be happy to contact you to discuss how we may be able to help you.

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