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Author Topic: g41/g42 cutting circle at end of arc  (Read 669 times)

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g41/g42 cutting circle at end of arc
« on: February 02, 2018, 04:19:32 PM »
When I try to use G41/G42 to cut a profile of a heart I am getting full circles at the end of arcs at the top of the heart lobes.  It apears to be at the end of the arcs. When I comment out the offending lines the profile cuts correctly.  If I change the sign of the arc center i value on a couple of the following lines the circle goes away but the tool path has a slight jog in it.

There must be something really simple here, but maybe I am too simple to see it. Attached are the file and the xml file of the machine.

No imoticon for tearing out hair, what little I have left.

Offline ger21

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Re: g41/g42 cutting circle at end of arc
« Reply #1 on: February 02, 2018, 07:08:20 PM »
My guess is that it's a bug in Mach3's comp, of which there are many.
I tried the code in a different control, and did not get the same circles, although I got other errors in other places.

Part of the issue is that comp can struggle with lots of short segments, and there are moves that appear to be as small as a few thousandths of an inch in there.
Gerry

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Re: g41/g42 cutting circle at end of arc
« Reply #2 on: February 03, 2018, 04:20:14 PM »
Thanks Gerry,  I am beginning understand that.  I will try to redraw the part with very simple arcs, I might have to live with some poor tangence's. I might just try changing tool diameter and repost. In the original drawing when I analyzed the curves on Rhino there were lots of changes in radii and even some inflections that didn't make any graphical sense to the curve.  As they say, back to the drawing board.
Thanks again,

Greg