TS 16949 Clause 8.2.3.1 - Maintaining Process Capability

[p_tww]

process capability maintenance

TS2 required in clause 8.2.3.1 as " the organisation shall maintain manufacturing process capability or performance as specified by the customer part approval process requirements.""
question is " if client required CPK >1.33, and our initial study result was cpk=1.8(example) but dropped down to cpk=1.5 4 months later, Is it still satisfy the standard requirement,( cpk=1.5 still exceed customer required cpk>1.33)"

 

[Bill Ryan - 2007]

In a nutshell - Yes - you still meet the customer requirement. In the vein of Continuous Improvement, did your Standard Deviation change or did the Mean change, or both? Even though this kind of goes against my arguments in another thread, you should investigate what has changed and get the process back in order (1.5 Cpk is still producing (statistically) 7 ppm which, with my automotive customers anyway, is not good enough - no matter what their "Corporate Standard" dictates).

Bill

 

[p_tww]

In a nutshell - Yes - you still meet the customer requirement. In the vein of Continuous Improvement, did your Standard Deviation change or did the Mean change, or both? Even though this kind of goes against my arguments in another thread, you should investigate what has changed and get the process back in order (1.5 Cpk is still producing (statistically) 7 ppm which, with my automotive customers anyway, is not good enough - no matter what their "Corporate Standard" dictates).

Bill

Hi,Bill,
agreed your concerns. but

If you thought it still satisfied standard requirements, What about do you think the "process approval acceptance criteria" which was identifed in clause 7.3.3.2?????

 

[Bill Ryan - 2007]

If you thought it still satisfied standard requirements, What about do you think the "process approval acceptance criteria" which was identifed in clause 7.3.3.2?????

Maybe I don't fully understand your question. If the "client" has a requirement of >1.33 ongoing Cpk ("process approval acceptance criteria") , where are you not meeting that requirement? IMO, yes, something in your process has "deteriorated" somewhat from your "First Time Quality" index, but you are still meeting a customer requirement.

Am I missing something??

Bill

 

[howste]

I agree with Bill. It sounds like you still meet the requirements, but you should still investigate to find out why the Cpk is lower now. Also look at 8.5.1.2 Manufacturing process improvement

Manufacturing process improvement shall continually focus upon control and reduction of variation in product characteristics and manufacturing process parameters.

 

[p_tww]

I agree with Bill. It sounds like you still meet the requirements, but you should still investigate to find out why the Cpk is lower now. Also look at 8.5.1.2 Manufacturing process improvement

thanks for your input.
I agree with your opinion.
in clause 8.2.3.1, it also mentioned reaction plan should prepared for those unstable process. the dropped cpk means they are not stable, so the company should check the cause and initiate appropriate actions.
Also from acceptance criteria in process design output, the cpk result should be criteria for series production process.
I just surprised why the standard have this word" the organisation shall maintain manufacturing process capability or performance as specified by the customer part approval process requirements"

 

[Sam]

p_tww asks,
"I just surprised why the standard have this word" the organisation shall maintain manufacturing process capability or performance as specified by the customer part approval process requirements"

For DCX,Ford,GM; this statement refers to PPAP 3rd editiion para 1.2.2.9 - Initial Process Studies. Also refer to customer specific requirements for additional information.

 

[p_tww]

p_tww asks,
"I just surprised why the standard have this word" the organisation shall maintain manufacturing process capability or performance as specified by the customer part approval process requirements"

For DCX,Ford,GM; this statement refers to PPAP 3rd editiion para 1.2.2.9 - Initial Process Studies. Also refer to customer specific requirements for additional information.

thanks Sam,

I knew that, also in QS standard, I remembered that the company should maintain and/or? exceed the capability in ppap process.

 

[anilo]

Re: process capability maintenance

question is " if client required CPK >1.33, and our initial study result was cpk=1.8(example) but dropped down to cpk=1.5 4 months later, Is it still satisfy the standard requirement,( cpk=1.5 still exceed customer required cpk>1.33)"

Hi p_tww.

IMHO, you are, obviously, still satysfying the customer requirement.
But something has gone, or is still going, wrong in your process.

i think, even if you met customer requirement, you have to analyze the dropped causes.
And this not just for your customer, but for you.

Bye

 

[p_tww]

Re: process capability maintenance

Hi p_tww.

IMHO, you are, obviously, still satysfying the customer requirement.
But something has gone, or is still going, wrong in your process.

i think, even if you met customer requirement, you have to analyze the dropped causes.
And this not just for your customer, but for you.

Bye

Hi, Anilo

thanks for your concerns. I know that, It's just for discussion.