B
To me, the Detection Evaluation Criteria in the FMEA book is very vague and I need some guidance for a specific operation in our company. We make fasteners on cold heading machines with involves thread rolling. Very few actual error proofing devices are available for these operations and most of our inspection, i.e. heading blank sizes and thread gaging is done by the operator on a regularly scheduled basis using micrometers and thread gages. Since no actual error proofing devices are used on the machine for this gaging and these features are only measured by a person, my first choice would be to give Detection a 5 ranking since the operator uses both visual and gages to measure the part after it has left the machine. But the 5 designation also mentions 100% Go/NoGO gaging. We do not measure every part. Is there any way I could give this a Detection of 3 since we have several steps after the part leaves the machine where the parts are measured (again not 100%) such as last off, final inspection and several lab tests that involve actually driving the bolt into a threaded plate? Detection of 3 states error detection "in-station" but does this always mean some sort of mechanical error proofing device on the machine or can it mean error detection in multiple layers of operator checking at the machine as I think it states in the OR section of the description?