CPK

We apply Manufacturing Process Control principals in our production process. 

This assures a sufficient number of physical dimension checks to insure parts conform to our customers print.  We document these results so variation can be studied and using Six Sigma techniques can be reduced and Cpk can show a customer that control has been increased by continuously reducing variation in process.

See the “Six Sigma & Cpk Definition by Example” article for a detail of explanation.

Also see “The Six Sigma Model” article.

Tolerance ranges are always a point of discussion for thickness as well as part dimensions.  Gindor produces the part dimensions and our Supplier Partners produce the thickness dimensions.  The great majority of our steel rule dies are “Laser Made”.  Their tolerance range is physically assured to be ±.005” from mean dimension.  This is a Six Sigma tolerance with a Cpk of 2.0.  Our Material Supplier Partners quote a tolerance based on the thickness target given to them to produce.  However, the quoted tolerance around this target is Two Sigma tolerance with a Cpk of 1.0.  Why the difference?  These suppliers are quoting “Machine Tolerance” for the finished product tolerance.  This means that 68% of the 100% of parts produced will conform to their quoted thickness tolerance.  In our experience, the thickness tolerance given must be doubled to include Four Sigma, 95%, of the produced parts reaching a Cpk of 1.33.

As this quoting practice is common for Material Suppliers, special consideration must be given to parts where close thickness tolerance is required for performance.  Details of manufacturing history of a specific material compound or style should be discussed and detailed so that the customer can understand fully what a specified material can be expected to physically measure.

Gindor employs Dial Calipers, Snap Gages, Pin Gages, Micrometers and a MicroVu Video CMM to measure part dimensions.