[Da...] Posted July 8, 2019 Share Posted July 8, 2019 Anyone know if there is a way to report out the length and width of an ellipse? Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/ Share on other sites More sharing options...
[Ri...] Posted July 8, 2019 Share Posted July 8, 2019 Can you not report the D1 and D2? Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102570 Share on other sites More sharing options...
[Da...] Posted July 8, 2019 Author Share Posted July 8, 2019 Yes, but ideally what I need to do is to report out physical length and width of the ellipse. Attached is a screenshot of a scan of an elliptical feature. There are some irregularities due to welding that I would like to take into account. I think I found a way to do it in Calypso by creating an XZ and XY plane and using those to intersect the feature. From there I can combine the two intersection results.Capture.PNG Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102572 Share on other sites More sharing options...
[Ri...] Posted July 8, 2019 Share Posted July 8, 2019 Ah OK. If that's the case, I would just use Curve, and create the intersections that you are looking for. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102574 Share on other sites More sharing options...
[Da...] Posted July 9, 2019 Share Posted July 9, 2019 Use curve, then ask for curve distance. You can ask for any coordinate. It's in Size, Curve dimension. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102576 Share on other sites More sharing options...
[Da...] Posted July 9, 2019 Author Share Posted July 9, 2019 Thanks for the tips. Much appreciated! Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102578 Share on other sites More sharing options...
[Re...] Posted July 10, 2019 Share Posted July 10, 2019 Not sure if this is a correct way to do it, but it seems to work for me if the minor and major diameter is not too extreme. I use the cmm with an active head and program a median circle size and report the maximum circumscribed and minimum circumscribed size or the min/max 2 point diameter. I'm not sure about the welding irregularities - perhaps filtering? Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102580 Share on other sites More sharing options...
[Ri...] Posted July 10, 2019 Share Posted July 10, 2019 The Max/Min would not be good for an ellipse. Those algorithms are based on mathematical equations of calculating the 3 most extreme points. The 2-point diameter method could work. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102582 Share on other sites More sharing options...
[Da...] Posted July 10, 2019 Share Posted July 10, 2019 Hello, make it a closed curve then ask for CURVE WIDTH. It's in Size, Curve dimensions. Ask twice, once in each direction. That's what that feature is for. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102584 Share on other sites More sharing options...
[Re...] Posted July 10, 2019 Share Posted July 10, 2019 Richard - I often thought that the mathematical algorithm on the circle evaluation would not be the best method and that the 2 point diameter method would be better. However I would always get the same result by either method. Maybe its due to our ellipse being highly precision ground. actually our ellipse are not a true ellipse, they are more of a spline. But I have to report the min and max. I would hate to change something that seems not to be broken, however I'm open to learn of a better method. Thanks for your input. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102586 Share on other sites More sharing options...
[Re...] Posted July 10, 2019 Share Posted July 10, 2019 Dave - For my so-called ellipse I tried to use curve, but I had a difficult time with clocking. Our ellipse has nothing to time to but itself. any good methods for establishing rotation? If I could establish a good method to clock to I would give curve another try. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102588 Share on other sites More sharing options...
[Da...] Posted July 10, 2019 Share Posted July 10, 2019 If you can't clock the ellipse then none of the other methods will work either. Do you have a model? If so, You can use best fit to the model allowing rotation in the Z axis. The amount of rotation is reported ( you may have to use a results element to find it ) and you can create a new alignment with the rotation applied. Now you can use curve expansion in both directions. Does that make sense ? I get a bit excited about this type of thing. 🤣 Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102590 Share on other sites More sharing options...
[Ch...] Posted July 10, 2019 Share Posted July 10, 2019 I would try and get Dave's recommendation to work. I measure weird slots/ellipses and I do exactly as Dave does. I measure it with curve then use Curve Width to measure it. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102592 Share on other sites More sharing options...
[Re...] Posted July 10, 2019 Share Posted July 10, 2019 Unfortunately I do not have accurate cad models for these parts, however the cad model would have the same min and max value. But the results seem to be correct with the circle scan using an active head and the different evaluations. I originally tried to use curve but was unsuccessful. I'ts been awhile but I did try the best fit thing, but if it wasn't near the cad rotation it would not work, and when it was close to clocking the result were not repeatable. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102594 Share on other sites More sharing options...
[An...] Posted July 11, 2019 Share Posted July 11, 2019 Please sign in to view this quote. Use the two focal points of the ellipse to establish a planar alignment. Link to comment https://qualityforum.zeiss.com/topic/18236-ellipse-length-and-width/#findComment-102596 Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in