Capability Indexes for ISO/TS16949 - Cpk & Ppk after PPAP

A

asirigoyen

I have always work with Cpks of 1.33, one collegue told me that this was the standard for QS9000, but know with TS, the requirement is to have the same capability of the part approval, so it means that when we PPAP at 1.67 Ppk/Cpk, we should keep in our process a Cpk of 1.67??? I hope some one can help me so I can be prepared for my next audit.

Thanks
 

Jim Wynne

Leader
Admin
asirigoyen said:
I have always work with Cpks of 1.33, one collegue told me that this was the standard for QS9000, but know with TS, the requirement is to have the same capability of the part approval, so it means that when we PPAP at 1.67 Ppk/Cpk, we should keep in our process a Cpk of 1.67??? I hope some one can help me so I can be prepared for my next audit.

Thanks

Cpk level is a customer-specific requirement. If your customers use the AIAG PPAP system, the expectations may be found in the PPAP manual (pages 6-8 of the 3rd Edition).
 
R

ralphsulser

I think the PPAP manual cover it. TS16949 does nort specify CPKs
TS 7.3.6.3 says you shall conform to the product and manufacturing process approval procedure recognized by the customer.
 

Caster

An Early Cover
Trusted Information Resource
It is in the CSRs

asirigoyen said:
I have always work with Cpks of 1.33, one collegue told me that this was the standard for QS9000, but know with TS, the requirement is to have the same capability of the part approval, so it means that when we PPAP at 1.67 Ppk/Cpk, we should keep in our process a Cpk of 1.67??? I hope some one can help me so I can be prepared for my next audit.Thanks

asirigoyen

I am at home, so I don't have my "big honkin binder". But if memory serves, the requirement is not in TS or PPAP, it is in the customer specific requirements, look for a table.

You are almost correct. If your Cpk at PPAP was 3.8 say, you don't just have to keep it at 3.8 you have to continuously (continually?) improve it!

Good luck, just tracking current capability is a massive job for us!
 

antoine.dias

Quite Involved in Discussions
In the ISO TS it says ( 8.2.3.1 )
quote:
The organization shall maintain manufacturing process capability or performance as specified by the customer part approval process requirements.
unquote

So, for some customers this means PPAP, for others it will be CSR.

Best regards,

Antoine
 

Statistical Steven

Statistician
Leader
Super Moderator
No standard will dictate a Cpk value specifically, because Cpk values are abitrary. As has been stated, meeting the customers requirement with some certainity, and repeatability is the mantra.

Cpk and Cp are driven by the specifications and the process variation. The customer should set the specifications, but in many cases, those specifications might not be realistic (either too tight or too wide).

The process variation can be estimated in several different ways, leaving the Cp or Cpk value to interpretation.

Just my $0.02
 
L

Leonor Santos

hello,

i can i manage Cpk linked with continuous improvement?
I need actions to improve my CPk.
 
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