Is Kappa Study Required during PPAP (Production Part Approval Process)?

Ramani Parthasarathy

Starting to get Involved
#1
Hi,
Kappa study is time consuming as far as sample selection is concerned,can anybody let me know if this study is required during PPAP.

thanks in advance
Ramani.Parthasarathy
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#2
I don't know if it's required but I do know that is useful. It is worth the time to understand your measurement error including the error of inspectors or test equipment that make categorical judgments.
 
P

Pazuzu - 2009

Guest
#3
I've gone through the 4th edition of the PPAP manual and nowhere is the Kappa study mentioned. Although it is a good idea to find where the comparisons are...no it is not required.

CAVEAT ALERT! There are many other Covers in here with vastly superior PPAP knowledge that may state otherwise. If so I'd be interested in knowing about it.
 

Jim Wynne

Forum Moderator
Moderator
#4
Hi,
Kappa study is time consuming as far as sample selection is concerned,can anybody let me know if this study is required during PPAP.

thanks in advance
Ramani.Parthasarathy
Kappa isn't required explicitly, but some form of attributes gage study is required for any attributes gages cited on your control plan. Check with your customer and find out what's expected.
 
D

DDaenen1

Guest
#5
First of all, what do you mean with "kappa-study"? Do you refer to the Measurement System Analysis Study (PPAP item 8) or to the Initial Process Study (PPAP item 11).

I don't know which PPAP Manuals some of you are reading, but both items need to be fullfilled to get full PPAP approval. A Gage R is mandatory for attributive measuring equipment, Gage R&R is required for variable measurement equipment. As far as sample selection goes for the MSA, you should randomly take a number of parts from your production line, no proper selection need to be done apart from ensuring they are OK-parts. The study will show if the variation is to be found in your products or in your operators.

Without proper GR&R, you cannot do a proper Initial process study anyways.

As far as the initial process study goes, this needs to be completed for all significant characteristics that have been identified on your product/process. If you do not have any SC's , than i would wonder if a proper component review was conducted.

If we are talking initial process study, there should also be no "sample selection". The standard requirement is that you collect a significant amount of OK-parts (>50) from your R@R and use these to conduct the the capability study.

So basically, yes, according to PPAP 4th edition, both items need to be fullfilled.

Hope this helps,


Dominique
 
Last edited by a moderator:

roland_lu

Involved - Posts
#6
I finally got out of automotive industry half year ago. Hopefully I would not have to return to it.

Sample selection is very much troublesome for attribute gaue study. It is easy to make "black/white" calls when the samples are white or black, and the study is more concerned about how the measurement system makes calls on the "grey". So the boundary samples are needed, quite often you will have to make them on purpose (not taking them from the normal production process, that is for sure). When you are doing PPAP for Ford, and you have new attribute gauges, for instance, you would need to have 50 samples ( :mg:), 3 appraisers to make 3 calls on each sample, you would really appreciate this kind of paper exercises.:mad:

I hope people (customers) understand what they are talking about.

Good Luck!
 

anandqgp

Involvement Access - Posts
#7
Dear friend

I dont think you should be confused so much. Is the aim to comply with a documentation requirement or the aim is to retain the customer for a long time. Well if the aim is retain your customer for ever, then you should do every thing right.

Talking about Kappa. If you are not making any attribute studies, then KAPPA is not required since for variation study you need only GRR studies. The moment your variation becomes Operator dependent then Kappa comes in.

Have you ever thought about what MSA studies are and what its purpose is. Its purpose is simply to find out the Variation spread consumed in the process variation. You are aware about the limit i.e., 0-30%. The more the area it occupies in the process spread, the worse the impression the customer has about your company. Perhaps this could be another case Type I error.

This termite like "Spread Absorption" by the measurement system of the process variation needs to be reduced or eliminated. This termite consists of Operator variation and/or Gage variation.

So if you are interested to eliminate the TERMITE hurting the process and your business, you will welcome doing KAPPA every time there is need for doing so.

I hope your question is answered. If not,you may come back since all such forums are both-way learning processes.:nopity:

HS Anand
 

terranceyu

Inactive Registered Visitor
#8
Hello guys, I am newly joined in QA Engineering filed, and actually completed the attribute GRR study based on the thumb pressure. However it has variance to every operators. When the inspectors tested the samples developed by myself and another engineer, it seems to have a lot of unmatchness. The same condition also applied to the inspectors who possessed on hand knowledge for almost 3 years. Is it mean they are not qualified, or the sample standard is simply too tight and not reasonable. I think it is reasonable tough..:cool:

And when comes to kappa study at page 2, how am I going to proceed, since we have three appraisers at page 1, but only two appraisers column (A and B) to filled? I attached the file for your better understanding.
I hope my questions could be answered.

Talk to me.

Regards,
Terrance
 

Attachments

A

ajf

Guest
#10
Kappa isn't required explicitly, but some form of attributes gage study is required for any attributes gages cited on your control plan. Check with your customer and find out what's expected.
First, you need to review your control plan to see if you have any attribute test and monitoring to be done. If it is part of your quality control plan, then next ask the customer if he requires Attribute GR&R to be performed and by which method should you use and report it.

Kappa is only one of a couple Attribute GR&R methods.
 
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