Customer wants PPAP on Old Parts to New Standards

[Golfman25]

How do you handle the situation where you have parts, designed, tooled and run for years prior to today's standards? We have several old parts, started up prior to QS, PPAP, AIAG and all the fancy measuring equipment we have these days. Now we are being asked to PPAP these parts and by today's standards we don't have a prayer.

For example, tooling built back in the day and the part was checked on an old style optical comparator. Picture some old guy, behind the curtain, eyeballing the part, saying good/bad. Today, the part is checked on a super fancy automated 3D computerized electron machine (which cost more than the original tooling did). Of course, the numbers don't quite match and the part is "no good."

Then there are the old gages, calipers and what not that can't "pass" an MSA. They seemed ok for years, but by todays standards, no go.

It just seems like a big can of worms to me.

 

[Marc]

Re: Old Parts, New Standards

Can of worms and pi$$ing matches are forecast for your future.

 

[Stijloor]

How do you handle the situation where you have parts, designed, tooled and run for years prior to today's standards? We have several old parts, started up prior to QS, PPAP, AIAG and all the fancy measuring equipment we have these days. Now we are being asked to PPAP these parts and by today's standards we don't have a prayer.

For example, tooling built back in the day and the part was checked on an old style optical comparator. Picture some old guy, behind the curtain, eyeballing the part, saying good/bad. Today, the part is checked on a super fancy automated 3D computerized electron machine (which cost more than the original tooling did). Of course, the numbers don't quite match and the part is "no good."

Then there are the old gages, calipers and what not that can't "pass" an MSA. They seemed ok for years, but by todays standards, no go.

It just seems like a big can of worms to me.

In the spirit of continuous improvement, aren't you interested in the capability of your measurement systems and manufacturing processes?

 

[Golfman25]

No, not on an older part. We show the part good by measurement systems used for years. To bring it in to there new fangled measurements it would require rebuilding the tools at several thousand dollars. And then buying measuring devices to boot. There is no point. Context is important.

 

[1010011010]

Hello Golfman25,

I'm with you on the context. However, if you say the parts are measured "not good" on new measuring equipment, but are measured "good" and old measuring equipment and I assume, that they are also functionally "good", I would ask a different question - Are the defined tolerances really necessary/adequate?

That's a question I often ask our Engineering.

There is a lot I could speculate about wear of tooling and capability of measuring equipment, but the tolerances, from what you told us, would be the first thing to question.

If there's nothing to change tolerance wise, you probably have to go with the current state of the art, that shows you, that your parts are out of spec and change the process accordingly. Going to less capable measuring equipment wouldn't fix the cause, but only disguise it.

Also, if anything happens, where this part is involved and the parts are measured on state of the art equipment, you'll be most likely not on the better side of this...

 

[Golfman25]

Hello Golfman25,

I'm with you on the context. However, if you say the parts are measured "not good" on new measuring equipment, but are measured "good" and old measuring equipment and I assume, that they are also functionally "good", I would ask a different question - Are the defined tolerances really necessary/adequate?

That's a question I often ask our Engineering.

There is a lot I could speculate about wear of tooling and capability of measuring equipment, but the tolerances, from what you told us, would be the first thing to question.

If there's nothing to change tolerance wise, you probably have to go with the current state of the art, that shows you, that your parts are out of spec and change the process accordingly. Going to less capable measuring equipment wouldn't fix the cause, but only disguise it.

Also, if anything happens, where this part is involved and the parts are measured on state of the art equipment, you'll be most likely not on the better side of this...

Sounds good but not practical at all. The tolerance are just the plain old "box" tolerances applicable to everything. In other words, little to no thought was put into them and their applicability. These days, we always ask "how are you going to measure it. We usually get blank stares from Engineering, who passes the buck to quality -- and they are on different planets. Bottom line, I agree. Ideally the tolerances would be wide enough to account for different measuring systems at different companies.

The problem is "changing" the process isn't that easy. Several thousands of dollars and several weeks at least to build new tool. To move something .005. Because some fancy machine says it's "no good." Doesn't make sense.

 

[Ron Rompen]

If I understand correctly, they are asking you to PPAP to the 'new' standard, and not asking you to change anything (including your method of measurement, tooling, or anything else that has been developed over the years). I recommend you involve your customers SQA right away.....get him on board to support you in submitting things 'as they are' and (where necessary) include a deviation request/change request.

 

[ncwalker]

Yeek.

This is going to depend on the reasonableness of your customer. I would approach it this way ....

1) Get as many historical parts that "worked" as you can.
2) Measure them on the new system, I assume they will be "bad".
3) Measure current parts on the new system as well, and overlay them. Student's t-test for means and an F-test for variances would be good tools.

Your mission is to demonstrate that the new measurement system is only highlighting the lack of understanding of the part. Hey, it happens, and you're right.

But, if you do this A/B type comparison where A is a representation of what you've always shipped and B is what you are making right now that your new gages say is "bad" and the result is that the OLD parts show "bad" too, that should allay your customers fears about the situation.

Then - you just write a deviation and shift the tolerances around.

 

[DRAMMAN]

I agree with Rompen
Try to talk to your SQE. This sounds like a very negotiable situation. Try to get your customer to explain WHY they want this. Are they having quality issues (maybe you should do a PPAP)? Are you showing up on some list of "Never PPAPed" parts? Try to understand their motivation and get them to understand your situation.

I have worked at companies that had these types of initiatives for older legacy parts. Usually, we just wanted to gain assurance we are receiving good quality and confidence in the supplier processes. Suppliers who resisted were rarely dropped. So one tactic is to ignore them and see how persistent they are.