Could anyone tell me what is relation / difference in Cpk and Ppk. where we should calculate Cpk and where ppk. What is difference is data collection?

kapoor,

check the following link, a very good discussion of capability!

Ppk formula - Can some one please help me - I have attached the sheet. (http://elsmar.com/Forums/showthread.php?p=92812#post92812)


Al...

Also see: Capability Analysis - Process Capability Indices (http://elsmar.com/Cp_vs_Cpk.html)

Look into the attached sheet to see difference between

1) Cmk – being machine capability
2) Ppk – being preliminary process capability index ( had to use it for Ford in
the start up of new projects )
3) Cpk – process capability index
4) Ppk – Performance capability index
5) Cpm – Targeted capability index


Hope this helps.

Also see: http://elsmar.com/Forums/showthread.php?t=15164 (http://elsmar.com/Forums/showthread.php?t=11520) Contemporary comments / clarifications appreciated.