Final process capability results - What I am supposed to present? Cp and CpK?

[toniriazor]

Hello everybody,
I will try to be short and to the point.
In 2 weeks FORD customer is coming to sign PPAP 3 for electrical distribution system wiring harnesses.
Today I got the agenda and I have to speak half an hour about <final process capability results> as part of PPAP I guess.
My manager is OFF and it will be first time I have to speak on this topic and I do not feel very confident or now exactly what to say.
First of all what I am supposed to present ? Cp and CpK ?
Thanks for support in advance.

 

[Johnnymo62]

Ford does not use Cpk. They use Ppk.

 

[GRP]

Ford does not use Cpk. They use Ppk.

Can you support this statement with a Ford document? I am curious about this since Ppk/Cpk (Pp/Cp) are both valid indexes in the world of SPC and an evaluation and comparison of them both can yield useful information.

 

[Johnnymo62]

Please see section 9.1.1.2 and Table A, pages 39-40 of the Ford customer specific requirements for IATF16949, to start with.

https://www.iatfglobaloversight.org.../12/Ford-IATF-CSR-for-IATF-16949-1May2017.pdf

 

[Johnnymo62]

Also look at section 11 of Ford Motor Company Customer-Specific Requirements For use with PPAP 4.0.

https://www.iatfglobaloversight.org/wp/wp-content/uploads/2016/12/Ford_Specifics_for_PPAP.pdf

 

[GRP]

Please see section 9.1.1.2 and Table A, pages 39-40 of the Ford customer specific requirements for IATF16949, to start with.

https://www.iatfglobaloversight.org.../12/Ford-IATF-CSR-for-IATF-16949-1May2017.pdf

Right. I have always discussed and reported Ppk, but it had never occurred to me Cpk was not to be used.

In the same page of the document you kindly referred it is stated that it is advisable to use Pp, Ppk, Cp and Cpk when investigating process capability issues.

 

[GRP]

Also look at section 11 of Ford Motor Company Customer-Specific Requirements For use with PPAP 4.0.

https://www.iatfglobaloversight.org/wp/wp-content/uploads/2016/12/Ford_Specifics_for_PPAP.pdf

Thanks for sharing

 

[GRP]

Hello everybody,
I will try to be short and to the point.
In 2 weeks FORD customer is coming to sign PPAP 3 for electrical distribution system wiring harnesses.
Today I got the agenda and I have to speak half an hour about <final process capability results> as part of PPAP I guess.
My manager is OFF and it will be first time I have to speak on this topic and I do not feel very confident or now exactly what to say.
First of all what I am supposed to present ? Cp and CpK ?
Thanks for support in advance.

Judging solely by our replies you probably have not gone too far.

The topic of SPC is wide and there is plenty of content to dig in the AIAG manual and The Cove discussions. It will probably be more succinct to advise you at least on what NOT to say.

In case of CC's, remember SPC on its own is not enough. If you check the links above, read through the process capability paragraphs. Your organization must provide assurance to Ford you will not ship NOK product for these characteristics. If you plan to do SPC for these you must also backup them up with SPC of process parameters.

Do not engage in an SPC presentation with Ford without the due 125 measuremets for the characteristic.

Ideally you will have prepared the measurements according to a rational sampling plan.

If you are using statistical software it would be advisable it is a Ford-approved mainstream program, or that you have gone through the validation as per PPAP requirements page 8.

As with any presentation, it will probably help you to prepare a list of topics to present. I do not know if you are still looking for ideas, but if you write down a list and share it then people could chip in.

 

[Johnnymo62]

Right. I have always discussed and reported Ppk, but it had never occurred to me Cpk was not to be used.

In the same page of the document you kindly referred it is stated that it is advisable to use Pp, Ppk, Cp and Cpk when investigating process capability issues.

Yes, that's true. I don't think investigating equals reporting. It's just my opinion and it's probably worth what you paid for it.

 

[toniriazor]

Judging solely by our replies you probably have not gone too far.

The topic of SPC is wide and there is plenty of content to dig in the AIAG manual and The Cove discussions. It will probably be more succinct to advise you at least on what NOT to say.

In case of CC's, remember SPC on its own is not enough. If you check the links above, read through the process capability paragraphs. Your organization must provide assurance to Ford you will not ship NOK product for these characteristics. If you plan to do SPC for these you must also backup them up with SPC of process parameters.

Do not engage in an SPC presentation with Ford without the due 125 measuremets for the characteristic.

Ideally you will have prepared the measurements according to a rational sampling plan.

If you are using statistical software it would be advisable it is a Ford-approved mainstream program, or that you have gone through the validation as per PPAP requirements page 8.

As with any presentation, it will probably help you to prepare a list of topics to present. I do not know if you are still looking for ideas, but if you write down a list and share it then people could chip in.

Hello and thanks for your good answer.
There are SC's for which the team will prepare Cpk and same for all CC's such as bolt tightening.
There's something that is not clear for me - what do you mean that I have to back up CC's with SPC of process parameters? can you clarify for me ?
If I have understood correctly I and the team have to do SPC (calculating Cpk) for all Significant and Critical characteristics listed in SCCAF/PFMEA/Control Plan ? is that correct ?
and another thing still not clear for me - For process crimping, terminal crimp height is SC, but it is quite difficult to do process capability (Cpk) on all terminals being used in production, so from one machine we must make 125 consecutive samples(crimped terminals) measure this characteristic, put the data in the software, set LSL and USL and check what is the variability. I see the things that way, but not sure if it is correct.
For me Cpk should be used in my case, not Ppk since Ppk is used for process performance, not process capability if I am not mistaken.

Thank you all for involvement.