Part Families and Single PFMEA - Can this be considered a part-family for PPAP?

[ChrisB]

I have seen part families mentioned in a number or posts, but only obliquely. I will throw in my bit and see what develops. I suspect there are several people who would like more information on how to create PPAP's for families of parts.

We extrude a polymer tube for an automotive client. This tube is used in several vehicles and is consequently cut to many different lengths, each with a unique part number. All of these parts are called out on a single drawing that specifies the profile and has tolerances for length ranges, but does not reference individual part numbers.

Can this be considered a part-family for PPAP? If so, what exactly does that mean in terms of requirements? A single FMEA seems reasonable, but what about the CP? Since each part number has a different length, does it require an indivual CP(also capability study, gage R&R)that specifies the length for that part number?

What about warrants? Can the warrant be submitted to the drawing number rather than the part number? Is there some way of addressing more than part number on a warrant, or should each number have a separate warrant, with all warrants referring to the a single PFMEA and control plan?

Anyone else have similar situations they have dealt with that can help keep the rest of us from suffocating in the flood of paper deluging our offices?

 

[Marc]

If only the length is different, it can classify as a part family. It just means all the processes and parts are essentially the same. I'm ashamed to admit I think I know one when I see one but I cannot give your a 'covers all' definition. A hermetic connector which only differs in insert size or pattern, and/or pin number and/or pin size, and/or shell size, and or shell connector mechanism, while the environment (and/or application) in which it is intended to used is the same is an example of extreme variability in a part family. They all go through the same pre-heat assembly, the same furnace at the same temp (dwell time does change from the largest to the smallest), same post-assembly and inspections and tests. Hermetic environments are typically high heat/low temp (thermal shock succeptable) marine or aerospace. But even here, you have to watch as there are requirements for discontinuity (max in ms) during vibration/shock for different applications.

A single FMEA *might* be reasonable. DFEMA or PFMEA? DFMEA might differ. PFMEA shouldn't. You would look at length as your variable but the process of cutting the tube to length should be the same - only the specific length spec would differ. Control plan can be the same - but cite the spec lengths for each part number.

Can't help you with the rest. Haven't done anm automotive family submission is a number of years. But - I would expect you'd do the part number. I'd talk to your SQA. Each situation and what each SQA will accept is different. That's what I used to do - and get a confirmation even if you do it as a phone contact record (with date AND time of day of the conversation).

[This message has been edited by Marc Smith (edited 03 July 2000).]