Level of detail of the error networks
The level of detail of an FMEA is determined on the one hand in the structural analysis - which functional groups are considered? Is every single component considered? A separate article will be written on this topic! This article is about the depth of detail of the fault network.
When reading technical books and guidelines on FMEA and defect nets, it is always pointed out that an FMEA lives from the completeness of the defects. So let's do it! First step Identify malfunctions of functions on all levels: degrading function, pulsating function, no function, ... too short, too long, too small, too high, too low, ... The list gets longer and longer ... Is it really necessary? What does it matter?
On the first level, the error sequence is described. Based on the importance of the defect sequence, the evaluation number B is determined. If the importance of the defect sequences is the same for the company, they can be combined. Example: a product from the medical technology, what we all know - dental drill! The importance of the failure sequence periodic function and stronger function is most likely evaluated the same and could be summarized. With the definition of the error sequences I try to have the evaluation catalog of the enterprise already in the back of the head.
On the middle levels it goes, around the linkage of error sequence and error cause. If the individual errors (such as too small or too large) have the same error sequences and error causes, then I combine them into one error. If consequences, causes or both are different, then I list the errors separately. Mostly I get only one or two errors per function.
The number of error causes depends on the avoidance and detection measures to be defined. If the measures are the same for the failure causes, then I group them together. However, I list special features individually to highlight them.