Non-uniform profile evaluation

[[Th...]]

A tolerancing change to a part was proposed to me earlier, that involved the addition of a non-uniform profile. This would be section 8.3.2 in ASME 14.5-2009, including figures 8-10 and 8-11, which detail CAD-defined tolerance bands. Does Calypso support tolerance zones like this? I don't have formal Curve training, and this would be the first time we use non-uniform tolerancing, so I don't have any existing CAD files to pull for experimentation.

[[Br...]]

I think you could do it with curve when you segment the tolerances within the curve. You could make the tolerances gradually blend. It could be a little tedious to get programmed but it can be done.

[[Th...]]

I suppose I could approximate tolerance changes like that, but the wording in the standard suggests that spline-like non-uniform tolerances would need to be defined in CAD. Since the tolerance zone would be constantly changing at a variable rate, and by extension not have any numeric data on print to work with, I'm not sure how I would set my segment zones to match.

[[Br...]]

In the CAD model or via basic dimensions on the drawing yes. That's all the information you should need to mathematically put the tolerance zone together. The tolerance zone isnt really "variable" in the sense that it dynamicaly changes based on the actual profile. It would be determined by the True Profile which would be relative to the DRF. But curve will handle this.

[[He...]]

Since you have all 3 shapes (nominal profile, upper tolerance and lower tolerance) in the model you do it like this.

1. Create curves for each shape.
2. In the dialog for the nominal curve you click the arrow in the bottom right hand corner.
3. Click segmented tolerances
4. On the bottom of the window you click something like "from curves".
5. Choose the upper and lower tolerance curves.

This will give each individual point in the curve its own tolerance.

[[Th...]]

Those were both the answers I needed. Ultimately the tolerance change on this part is probably going to be linear in nature, so I can use the functions provided to calculate the per-point band mathematically. Anything relating to tolerances that require the use of curve entities has been pushed back onto design, as they need to figure out how to define it in their CAD software.

[[Gr...]]

I attended GD&T classes thru our local junior college. The instructor provided this to us and it might help with your question.
Greg K

[[ka...]]

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Thank you for the tutorial! Did you like your GD&T classes at junior college? I am considering taking a course but sure yet...

[[Gr...]]

The junior college classes were informative and thorough in presenting everything. The instructor provided drawing and we had to apply the GD&T to them. Great class