Ford CSR Cpk/Ppk Requirements

dave.d

Starting to get Involved
In Ford's CSR there is a table titled "Ongoing Process and Product Monitoring" which defines a process as being in control if the Ppk is "Equal to or Greater than 1.33."

While looking at the prior CSR (2008) I found a table with the same title which is formatted in a very similar manner. In that table there is no reference to Ppk, but Cpk instead.

In the older CSR "Cpk" is preceded by the words "Historical Process Capability."

In the new CSR "Ppk" is preceded by the words "Process Capability."

Has anyone been in a position to discuss this with an auditor or Ford? If so I'm curious how that went.

Thank you,

Dave
 

dave.d

Starting to get Involved
Any idea why are they referring to Ppk as Process Capability instead of Process Performance?
 

AMIT BALLAL

Super Moderator
Any idea why are they referring to Ppk as Process Capability instead of Process Performance?
I didn't find anywhere in the CSR about Ppk being called "Process capability". Ford mentioned it as "Ongoing production process capability", keeping "performance index" in bracket.

Here is a snapshot of the same.

1646729152355.png
 

Matt Savage

Trusted Information Resource
If this helps, the SPC Reference Manual by AIAG (Automotive Industry Action Group) lists:
Cpk - The capability index for a stable process ... and
Ppk - The performance index ...
 

Jason Baur

Registered
In Ford's CSR there is a table titled "Ongoing Process and Product Monitoring" which defines a process as being in control if the Ppk is "Equal to or Greater than 1.33."

While looking at the prior CSR (2008) I found a table with the same title which is formatted in a very similar manner. In that table there is no reference to Ppk, but Cpk instead.

In the older CSR "Cpk" is preceded by the words "Historical Process Capability."

In the new CSR "Ppk" is preceded by the words "Process Capability."

Has anyone been in a position to discuss this with an auditor or Ford? If so I'm curious how that went.

Thank you,

Dave
I am meeting with my STA manager now regarding the transfer of work from one location to another. CPK is not used by Ford in his judgement. He said that this changed recently. He challenged me to look it up in the CSR. I did so and he is correct they use PPk of 1.67 for initial and PPk of 1.33 for long term. Makes no sense to me because they are different formulas. All industries outside automotive use PPK for long term and CPK for short term but the formulas are also inverted so it essentially is the same.
 
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