3D model-control drawing

I've posted this to the Solidworks group, and no one seems to want to touch
Hi group,
I have a question for the plastics oriented people in the group.
For years, we've been doing business with a select few local mold houses. We
know these vendors real well, and they know what we expect from them. What
we usually do is supply them with a 3D model and a control drawing that
shows critical dimensions and tolerances. This arrangement has worked out
pretty well, in most cases.
We now find ourselves in a client driven situation where we need to specify
an overall tolerance, relative to the model, for those features that aren't
specified in the control document. The parts may be freeform shapes and
would require a 3 axis CMM to measure.
Have any of you had to deal with a similar problem ?? If so, how did you
solve it ?
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If I understand your situation correctly, the features you are trying to define are non-prismatic, and difficult to show using discrete dimensions in a 2D drawing view.
Im my own experiences with this situation, the customer has defined datum target points for 3 datum references, and has only a profile tolerance. This profile tolerance is shown as unilaterial tolernaces for + and - deviation.. The cad model is a controled document, and for airfoil type of shapes, a listing points that are gridded on the surface is also controlled. The surface is measured by a CMM, and only the profile tolerance is shown on the report.
BTW, is/has anyone in this newsgroup been looking into ASME Y14.41 for product definition? It would seem to apply well to this situation.
MM wrote:
Reply to
Chris Gosnell
I had to deal with this situation, but from the other side. I worked for the tool shop. We were supplied a chart with about 100 points listed each with its own tolerance. It gave the x,y,z relative to the parts coordinate system. The part file we were supplied had those Datum points in it. We were required to provide with the tool a check fixture. With the check fixture we supplied back to the customer a new chart with the points dimensioned back to a 0 on the check fixture. I forget what the name of the machine that was used to check all the points but it apparently could do it quickly and all the operator had to do was to hit a start button and it would do the rest.
Reply to
John Morrison

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