Should Cpk be > 1.33 or 1.67 and according to which standard?

[mahesh jadhav]

hello sir,
can you please tell me Cpk should more than 1.33 or 1.67 and it is accroding to any standerd? how standerd deviation & Pp Ppk calculated.

 

[Howard Atkins]

hello sir,
can you please tell me Cpk should more than 1.33 or 1.67 and it is accroding to any standerd? how standerd deviation & Pp Ppk calculated.

There are various requirements for Cpk and Ppk.
Thee are specific requirements in the AIAG PPAP book but essentially the requirements are based on those of the customer.
These are minimum values

The calculation can be found b searching the forums

 

[qusys]

hello sir,
can you please tell me Cpk should more than 1.33 or 1.67 and it is accroding to any standerd? how standerd deviation & Pp Ppk calculated.

Automotive customers usually ask for Cpk major than 1.67. If you pursue ISO TS , AIAG blue books guidelines are usually seen as reference for process capability after input of the customers.

 

[mahesh jadhav]

thanks.....

 

[bobdoering]

Automotive customers usually ask for Cpk major than 1.67. If you pursue ISO TS , AIAG blue books guidelines are usually seen as reference for process capability after input of the customers.

AIAG aslo specifies the exceptions, where Cpk or Ppk is not applicable. They are worth looking at - too many people ignore them (especially customers).

 

[sylwia]

Value Cpk, Ppk must be agree with customer requirements.
Generally in automotive is: Cpk>=1,33, Ppk>=1,67 but for example for Daimler is: Cpk>=1,67, Ppk>=2,0; for Fiat Cpk, Ppk>=1,67