inspection friendly dimensioning

[bxbzq]

Hi,

In attached drawing, the key characteristic is the lower segment of the composite profile which controls perpendicularity and form of the cavity, and is the only one I want the metrology lab to inspect using CMM. The metrology lab is newly established and short of well trained and experienced inspectors. Look at the FRTZF of the composite profile tolerance callout, I would like to know:
Is the dimensioning and tolerancing scheme inspection friendly? The inspector I talked to does not think so. She kept saying she could not find a way to load the basic dimensions into PC-DMIS, not because she does not know how to use the software, but the way I draft the part.
What are the typical inspection steps to inspect the FRTZF?

Many thanks.

 

[axym]

bxbzq,

Here are some comments:
-The dimensioning scheme isn't particularly straightforward, but I'm not sure if there is a more straightforward way for that shape
-I would be very surprised if the basic dimensions could not be entered into PC-DMIS in some way
-If the dimensioning scheme is that unworkable, a different scheme could be used instead without changing the meaning (because the dimensions are basic)
-These days, the part geometry is typically defined as a CAD model and imported into the CMM software. Typing in dimensions from a drawing is outdated.

When inspecting this FRTZF using a CMM, points on the feature would first be inspected in a fully constrained coordinate system (probably ABC). Then the software would best-fit the points to minimize the profile value for the FRTZF while maintaining the relationship to A. I don't have PC-DMIS in front of me, but I'm 99.9% sure that it can do this without a problem.

Evan Janeshewski

Axymetrix Quality Engineering Inc.

http://www.axymetrix.ca