iSixSigma

Difference between cpkppk

Six Sigma – iSixSigma › Forums › Old Forums › General › Difference between cpkppk

Viewing 4 posts - 1 through 4 (of 4 total)
  • Author
    Posts
  • June 2, 2007 at 12:03 pm #47148

    JIJU JOSEPH
    ★ 10 Years ★
    Participant

    As per the def. in this site ppk is long term process capability & cpk is short term capability. But in the second edition of SPC( AIAG Manual) cpk is the limit of natural variation and ppk is total variation(cpk+special cuase variation). Anybody canclear my doubt?

    0
    June 2, 2007 at 1:45 pm #156855

    SS
    ★ 10 Years ★
    Member

    Both definition are same. Actually, short term capability of a process is due to natural variation or common cause variation whereas Long term capability includes both common cause and special cause variation.

    0
    June 2, 2007 at 2:36 pm #156856

    Fake Gary Alert
    ★ 10 Years ★
    Participant

    Cp & Cpk are used  for  short-term  capability and Pp,Ppk are  used  for  long-term  capability. 

    0
    June 2, 2007 at 5:46 pm #156859

    CT
    ★ 10 Years ★
    Participant

    Cp = Process Capability.
    Cpk = Process Capability Index. Adjust for Non-Centered Distribution
    Pp = Process Performance.
    Ppk = Process Performance Index.  Adjust for Non-Centered Distribution
    Ppk produces an index number (like 1.33) for the process variation. Cpk references the variation to your specification limits. If you want to know how much variation is in a process, use a Ppk measurement. If you want to know how that variation will affect the ability of your process to meet customer requirements, you should use Cpk.
    CT

    0
  • Author
    Posts
Viewing 4 posts - 1 through 4 (of 4 total)

The forum ‘General’ is closed to new topics and replies.