How does one handle dimensions on a control plan that are purely functional?

[ChrisB]

Dimensional Notation on CP

How does one handle dimensions on a control plan that are purely functional buy-offs? I have a situation in which a key dimensional characteristic is checked and bought off solely by Go/NoGo gages. The part is set up, ran, and checked with gages. At no point in the manufacuturing process is the key dimension measured, and due to the nature of the part, the dimension is almost impossible to accurately measure. Should this dimension be made "reference" and a callout added to the drawing that the part must pass a functional buy-off with the appropriate gages only? What should be done with regards to a capability study?

Any help would be appreciated. Thank you in advance.
Chris

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[Jesus Sanchez]

what we did were the go no go gages are functional we discuss this item with my custemer (GM Mexico) and obtain a waiver (letter from the sqa ) to check 300 parts in our ppap in front of his eyes and sign my control plan.
Personally i prefer to use a go/no go gages in my process because is more easy to my people to use. !!!

 

[Marc]

In many companies changes to drawings can be like making it to hell with a cold ice tea, but notes on product acceptance methodology would be a good idea.