Comments on: Calculate Capability Indices with Only One Specification
https://www.isixsigma.com/tools-templates/capability-indices-process-capability/calculate-capability-indices-with-only-one-specification/
Six Sigma Quality Resources for Achieving Six Sigma ResultsWed, 07 Jun 2017 12:21:17 +0000
hourly
1 https://wordpress.org/?v=5.7
By: Cesar Vasquez
https://www.isixsigma.com/tools-templates/capability-indices-process-capability/calculate-capability-indices-with-only-one-specification/#comment-6354
Wed, 07 Jun 2017 12:21:17 +0000https://www.isixsigma.com/?p=6400#comment-6354Zero in this case is not a specification limit but a process boundary and therefore should not be used in the calculation of a parameter that calls for a specification.
This is a common error many do not quite grasp. I have seen it too in a slight different situation like the specification of max bow -let’s call it b- in a bimetal that is supposed to be flat. In this case in this case if the specification is interpreted to be 0 to b (positioning the bimetal as an inverted U on the table and it always bends to the same side so there is no -b measures) the closer the part is to flat the worst the Cpk, unless using the unilateral b USL where farther away from b and the smaller the deviation will translate into a flatter more consistent part.
]]>