B

The 2nd edition of PPAP says we are suppose to calculate "Preliminary Process Capability" in the form of Ppk, and yet the SPC Ref. Manual says Ppk is "Process Performance" while Cpk is "Process Capability". So what gives?

Also by the definition of Ppk and Cpk formula, Ppk value cannot be greater than Cpk since the "sigma" in Ppk includes both common and special causes of variation. And yet the acceptance for Ppk is supposedly 1.67 but for Cpk it's 1.33.

Anyone's got an insight to this?????