Rate-of-change analysis applied to machine tool monitoring and maintenance schedules

In high-value manufacturing, production equipment is often calibrated on a regular basis to ensure it remains within the required absolute tolerance. However, this go/no go approach means that data relating to the rate of change of the condition of the asset is often lost or overlooked. This data can provide valuable insight into the current state of the machine, and provide estimates of when maintenance will be required to maintain the present level of performance. Analysing the rate of decay of certain machine capabilities can assist with optimisation of maintenance schedules, allow the cost of replacement parts to be reduced or spread out, and give more reliable estimates of machine availability. The reasons for the loss of this data and a proposed design of a system to capture it are discussed here.