Curve, Free Form, or what?

[[Er...]]

See attached.

So right now I am just taking space points and reporting the space point distances and the profiles of the points for internal use. Then using the max profile for the customer.

From what I've read on the forums I think Curve would be best. Could Free Form do it too? Pros and cons of each?

Multi.jpg

[[Jo...]]

If that is a notch in sheet metal, I think it hardly qualifies as profile of a surface. Using a touch point and formula to control immersion depth, you can do a 2d scan and profile of a line evaluation. If thickness permits, maybe multiple depths ?

[[Er...]]

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I agree a profile is overkill. No one wants to fight the customer over it.

That would be with Curve? Actually the plane the notch is in moves, so it would have to be measured in that plane and then referenced back to ABC datums.

[[Jo...]]

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Yes, Curve

If I understand your pic, the slot, and keyhole features have profile requirement back to datum, with no regard to each other. IF they are close to nominal position, just leave them in that alignment. If this is extrusion where you have a depth I would "create features" by sectioning those objects at a couple of depths and do a closed scan. Pick the worst of the scans and report Profile of that "surface" back to ABC. You can do a local alignment at each location if there are problems.

Just a pick at that print.. I believe that leader symbol is technically "all around" NOT All Over. That may be your "out" on that requirement. Need someone else to chime in on that.

ASME Y14.5-2018 FIGURE C-6 PAGE 324

[[Je...]]

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If we don't want to fight the customer about it, then you would need to evaluate it as a surface, because that is how the print calls out the feature. However, as John mentioned, I don't think the feature really qualifies as a surface due to thickness. I would ask the customer's permission to evaluate it using profile of a line and create a curve.

I recently finished taking both curve and freeform Zeiss courses. The instructor, Nick Janak, pointed out that the main difference between curve & freeform is how they are evaluated. A curve is evaluated from the nominal curve points as defined. Freeform is evaluated strictly from the nominal CAD model geometry. This requires accurate CAD models in order to have a successful evaluation.

My standard routine, depending on part thickness, is to evaluate the profile at several sections and then create a freeform surface that recalls the feature points from the previous sections. I report both the cumulative profile result and line sections. This would be unnecessary in your current example, though.


Jeff Frodermann
Meier Tool & Engineering
Brooklyn Park, Minnesota

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[[Er...]]

Thanks Jeff! That was excellent information.