Black Diamonds on Prints

1 Reply

Black Diamonds on Prints

Posted by Dominick Cianfarani on Feb 27, 2019 11:49 am

Hello,

Wondering what opinions out there are with regards to the following callout on a print of ours (see attached pic).   What if any standard is out there to give guidance on what we are obligated to report in the PPAP and control in process going forward.  Our internal engineering standard says that we must not only provide capability studies on all black diamonds (significant characteristics), but control them in our plan for the process as well.  However, it does not distinguish based on the specific placement of the diamond on a particular dimension.  The real question lies in, does the black diamond only apply to the feature reference frame containing the positional tolerance or am I obligated to do the studies and control parameters around measuring in process on the diameter as well

I welcome all thoughts and of course references to whatever standards may be out there on practices in either ASME, ASQ, or otherwise.

P.S. - I have my own experience in how I should go about reporting it, but I'd like to hear what others are/have done when encountering these in this fashion or CTQs for that matter shown in the same manner, since I hear conflicting statements from multiple different resources within my company.  Thanks folks.
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Re: Black Diamonds on Prints

Posted by Kaiwen Cheng on Mar 4, 2019 7:52 pm

In your example, the true position of the feature is the significant characteristic.  You are not required to perform capability studies on other dimensions.