4. Analyze failure modes

The group now meets to analyze failure modes. Collectively, we look for these failure modes for each of the assembly phases. As shown in the figure below, PFD phase 1, which consists in assembling the 13 mm +/-1.5 mm distance, can present two failure modes, namely "max. distance out of specification" and "min. distance out of specification". These failure modes are based on discussions between members of the analysis group.

This stage should be carried out until all the phases of the process have been completed (working vertically from one phase to another in an iterative fashion). The facilitator should not hesitate to move the study forward if the failure modes are blocked. The aim is not to trap every conceivable failure mode. As this is a living exercise that evolves along with the products, there will be plenty of time to look for other modes later on....