Condition Based Maintenance (CBM)

Condition Based Maintenance (CBM) takes Predictive Maintenance (PdM) to the next level and the major benefit is that all maintenance activities are focussed where they need to be, maintenance truly based on the condition of an asset. The use of CBM allows maintenance actions to be scheduled, or other actions to be taken to prevent failure, and hence mitigate the consequences of failure. Condition Monitoring (CM) is a fundamental part of CBM and has a unique benefit in that conditions that would shorten the normal lifespan of a machine can be addressed before they develop into a major failure.

When a CBM Strategy is employed, all maintenance tasks are performed depending upon the ‘actual’ condition of the equipment to be maintained. What is set up in the maintenance planning schedule is what has been deemed as the correct monitoring technique to identify the relevant Failure Modes (FM) at the correct time interval. To decide these the following are used:

1. Failure Modes – Failure Mode & Effects Analysis (FMEA)
2. Monitoring Technique – From the FMEA selecting the best method of monitoring
3. Timing – For the type of Failure look at the expected Period to Failure (PTF) Curve along with the technique to be applied and aim to monitor two to three times within that PTF period.

Early identification of faults enables better scheduling and planning, ensuring spare parts availability and most importantly to maintain the optimum life cycle for your machinery.

Taking the PdM, Preventive Maintenance (PM) and Run To Failure (RTF) example to the next stage:

An individual bought an incandescent light bulb. The manufacturing company mentioned that the life span of the bulb is 3 years. The individual has the opportunity to observe the bulb operation daily. After two years, the bulb starts flickering. The individual predicts at that time that the bulb is going to fail very soon and decides to change it for a new one, as such an order is placed to purchase a replacement one. As you can see the benefit of CBM is that not only is the bulb replaced at the optimum time but also there are no ‘idle’ spares sitting on the shelf.