What is the criteria for inspection of a dimension.

[lutky35]

I am working with an existing design of a machined plastic part. The tolerance block states, .XXX +/-.002. Would all 3 place dimension be considered tight toleranced and show the need for inspection.

 

[dingy2]

If most dimensions could cause a problem, then those dimensions would be targeted for ongoing inspection.

How do they impact the function? On a scale of 1 - 10, they should be rated with 1 having very little impact while 10 is "critical".

How well are the part processed relative to the specification. Again, rate it from 1 - 10 with 1 have a Cpk of over 1.67 and 10 not making spec. Now you have the decision analysis data. Just get the product of impact and complying to specification. We use this product to determine how often one should inspect the features with the higher values more often than the lower values.

Dave D.

http://www.qmsi.ca

 

[Duwe6]

In addition to running 100% Inspx on your 14 Critical Dim's, you should also run Statistical Process Control on them, too. Assuming the machine/machinist are as good as machinist thinks they are, your Inspx rate may be able to be reduced to 5-20%.

Does the Idio . . . Engineer that drew up this plastic nightmare have any idea the Inspection costs, and the anticipated "Scrap & Remake" rate ?!!?