Cpk considers variation within subgroups (common cause), Ppk considers total variation, which means variation between and within subgroups ( common cause and special cause). Use it when you want to measure a system’s actual process performance.ģ. It is used to measure the performance of a system to meet customer needs. Ppk is how the process actually did (long term). Why This Matters: Formulas for Cp Cpk and Pp Ppk look similar, but one uses sigma estimator while the other uses stdev. It is used to measure the potential capability of a system to meet customer needs.Ģ. Dont Confuse Cp Cpk Formulas with Pp Ppk Formulas. is a statistical difference between Cp and Pp and Cpk and Ppk all we. Cpk is the potential of a process to meet a specification (short term). variability and Cpk and Ppk which indicate process capability considering both. You cannot use it to predict the future because the process is not in a state of control.ġ. Ppk tells you how the process has performed in the past. Adjustment of Process Performance (Pp) for the effect of non-centred distribution. Cpk tells you what the process is CAPABLE of doing in the future, assuming it remains in a state of statistical control. Adjustment of Process Capability (Cp) for the effect of non-centred distribution.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |