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Issue with radii corners in Curve


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When I run a curve profile, the corners are looking very wonky (see pic below).  I have tried different filtering methods, but nothing seems to work.  Any ideas?

 

Using a 1mm sphere probe on a Calypso G2 with RDSXXT.

Curve issue.JPG

Curve Info.JPG

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What size is the radius being scanned there? That 1mm styli might be too large? In addition, have you tried adjusting the speed and point density?

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They are .060" radii.  I also tried dropping the points down to 2000 and still having the same issue

2000points.JPG

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I would try measuring them separately as radii. If that's an option. Single points and constraining location which ever work-plane it's in. I'm assuming in XY? The other thing I'd look at is the surface finish of that edge. If it's too rough the styli might be "skipping" along the surface.

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Its a limited dimension drawing, so a lot of these features are .010 profile to |A|B|C|.

Yes, its in the XY plane.

This part has several areas like this, and I am trying to get away from doing circles (using TP) and planes (using Profile) for everything.

 

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I also have a similar issue on a slot feature.  The radius on the end of each slot is .050.  I used a 1mm dia probe and ran it slow (.05 for speed) and taking a point every .025".

 

Here is the result

image.png.1a07c5c54b35c033e82589ff93901687.pngimage.png.ff8065532fa32043c967048e830ed743.png

image.png

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  • 2 weeks later...

OK, got another one doing the same.  Running a profile around a boss, the corners are modeled sharp, are probed as sharp, but shows chamfers on plot, and is out of tolerance.

 

Any help would be appreciated. 

 

 

CURVE ACTUALS.jpg

Curve Plot.jpg

Curve settings.jpg

Curve settings - 2.jpg

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In that case you should measure them as individual curves, model that as a small radii or use more segments.

Problem is scanning around sharp corners and evaluation also - similar with tolerance band.

You can also mask some of problematic points around corner.

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Jake - a few things:

  • The recommendation is 3:1 of actual to nominal points - so in a lot of your cases you have 2000 nominal points, so you should be collecting 6000 actual points. 
  • Sharp corners are extremely difficult to measure correctly because 99.9% of the time there are no nominal points on the sharp corner, so the software doesn't have a great idea on how to round the edge. Very rarely do true sharp corners exist, so sometimes you can "cheat" with an unknown curve to get it to wrap around the edge correctly. Most of the time I would recommend to just measure the segments independently (say you have a 200 point nominal curve that point 1-100 are the first line of the wall, and 101-200 are the second line of the adjacent wall; you can tell the software to measure 1-100; and then have another segment inside of that curve to measure 101-200). You also might have to limit evaluation (Nom. Vector Direction) right at the edge. 
  • You are possibly defining too many nominal points. My general recommendation is when you build them, tell it 25 points per segment. 
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