Out of Tolerance on Non Critical Dimension (PPAP)

V

vardar3

#1
One dimension is out for a max under fill condition on a rivet. This is for initial PPAP. Our engineers agree it is no issue, and I don’t think they are in any rush to change the print to accommodate the out of spec condition.

I don’t want to approve the PPAP because of the out of spec condition, but is there some way I can get around this issue without a print change, such as having our engineers give authorization to run parts in this condition. Would this make it acceptable for me to approve the PPAP?
 
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Ninja

Looking for Reality
Staff member
Super Moderator
#2
Re: Out of tolerance on non critical dimension

Hello vardar3,

This is not a direct answer to your question...but an answer none-the-less.

If there is a spec for something that doesn't matter...why is it a spec?
Whether you waive it now, or fill out paperwork to "make it ok this time", you will still be moving forward with a meaningless requirement that can affect your cost.

If the print requires something that is not needed, change the print. (Whether the engineers are inclined to at this time or not). If they agree that it doesn't matter, then make the print right. Having correct prints matters.

Going through PPAP, whose intent to some degree is to make sure that material you buy works, and accepting material that works even though it doesn't match the print opens the door for the next time there is out of spec underfill "You accepted it last time for PPAP, take it this time too" and simply leads to more meaningless paperwork. Take it off the table now by correcting the print.

Note that "Correcting the print" is really just saying "Capture the true needs of the process". It seems that the current requirement for underfill is not a true need of the process.
 

Jim Wynne

Staff member
Admin
#3
Re: Out of tolerance on non critical dimension

One dimension is out for a max under fill condition on a rivet. This is for initial PPAP. Our engineers agree it is no issue, and I don’t think they are in any rush to change the print to accommodate the out of spec condition.

I don’t want to approve the PPAP because of the out of spec condition, but is there some way I can get around this issue without a print change, such as having our engineers give authorization to run parts in this condition. Would this make it acceptable for me to approve the PPAP?
There are a couple of options:
  • A permanent waiver of the requirement. You should have some sort of process in place to cover this. You document the waiver, have it properly approved on your end, and have the supplier include it in the PPAP submission, with a reference under "Additional Engineering Changes" on the PSW.
  • An ECN/ECO or whatever you call it, duly approved, along with a marked-up print, which the supplier includes in the PPAP submission as explained above. This allows for formal approval for the supplier while giving your engineering people a little breathing room for formally updating the drawing.
Between the two, I thing the second option is preferable so that the drawing always represents the current requirements.
 
T

TErickson

#4
I'm in a similar (but different) situation. I submitted a PPAP to my manager, and without his looking it over, it went to the customer with out of tolerance dimensions. Now we just received a corrective action for submitting the PPAP with out of spec. dimensions. There are no critical dimensions on the drawing, so now I'm torn, between asking the customer for a deviation and just "cherry picking" a new PPAP.

FYI: I will be remeasuring new parts and collecting new data, with a deviation request if needed.

Thoughts???
 

Jim Wynne

Staff member
Admin
#5
I'm in a similar (but different) situation. I submitted a PPAP to my manager, and without his looking it over, it went to the customer with out of tolerance dimensions. Now we just received a corrective action for submitting the PPAP with out of spec. dimensions. There are no critical dimensions on the drawing, so now I'm torn, between asking the customer for a deviation and just "cherry picking" a new PPAP.

FYI: I will be remeasuring new parts and collecting new data, with a deviation request if needed.

Thoughts???
The customer knows that you had discrepant parts, so any cherry-picking you do at this point could just exacerbate the situation. Whether you should ask for a deviation or just correct the problem(s) is a function of what it will take to correct the problem and the risk of further irritating your customer.
 
A

amit_rd

#6
I request the attention towards one point:

Deviation for not meeting specification should not be the target, irrespective of the criticality of the spec. Question is whether the process is capable to produce within spec or not! If the answer is yes and the process is capable then why take deviation. If there is a process limitation, then it may be discussed with the customer with a waiver request.
 

Golfman25

Trusted Information Resource
#7
I request the attention towards one point:

Deviation for not meeting specification should not be the target, irrespective of the criticality of the spec. Question is whether the process is capable to produce within spec or not! If the answer is yes and the process is capable then why take deviation. If there is a process limitation, then it may be discussed with the customer with a waiver request.
Unfortunately, many customers don't acknowledge that there can be process limitations. We call it "easy to draw, impossible to make."
 
S

ssz102

#8
and these change had approvaled by costomer, and if this dimession are affect the final part's function or using?
 
A

amit_rd

#9
Unfortunately, many customers don't acknowledge that there can be process limitations. We call it "easy to draw, impossible to make."
I understand your point. Not many OEMs are doing "Design for manufaturing" and "Design for asembly" the way it should be done and then waste a lot of time and effort in resolving "problems".
 
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