Random arcs

[Mike Windsor]

Hi I'm using visual mill 5 and have been doing some v carving . When cutting some letters I get random circles in the cutter that show up as cones in the v carved font . Sometimes they are very small and other times large enough to obliterate the font . I sent off a couple of pictures to Mecsoft as well as the cutting files , but they couldn't find the circles in the toolpaths , nor could I . I ran the files in the shopbot previewer and could not see the errors there either , but they do definately show up in the wood . I'm running a prt at 60 ipm under windows control software version 3.4 . ---Could this be a control software problem , or loosing steps ? ---Anybody else ever had a similar problem ? Thanks Mike

[beacon14]

I did have a very similar problem way back when, when I was using EnRoute (before PartWizard came out). The code would have 1/8" diameter circles embedded in a few places in a multi-thousand line file. By using FG and single stepping through the affected areas I finally found the offending lines of code, and deleted them. Never figured out why it happened (it happened 2 or 3 times, on different projects), but finally PartWizard was released and now I'll sell you my old copy of EnRoute real cheap.
Sorry I can't offer any real help.

[jthelen]

Mike
Did you do a simulate until in Visual Mill to see if the circles show up there? ( I have VM 4)
Does VM use the letter width to control the depth, or are the cuts all the same depth? (never used VM for this)
Do you have the power to your controller and your computer on a UPS? (Power spike problem)
How fast is your Z speed, if you miss steps on the lifts your cutter could get progressively deeper. I had this problem and it turned out to be a dirty ball screw. It would lock up for a millisecond on the lift and brake free on the next down stroke. Not having made all the up steps it would be a little deeper. Very random and took a long time to find.

I use Rams skeleton feature for V carving and have seen similar things. Not so deep as to trash the font (yet) but little circles usually where the tool paths meet in a serif.
Hope some of this helps and good luck.
Jim

[Mike Windsor]

HI I've mannaged to zoom in on the toolpath simulation in the shopbot previewer , and yes indeed the small circles are in the toolpaths . However they are not there in the VM preview toolpath before post processing .---And yes Jim VM 5 does incised v carving controlled by the font outline ( or whatever closed polyline shape you want )
3852

[bill.young]

Hey Mike,

There was an issue like that with Vector, where it would occasionally create arcs that were so short that the ShopBot software reads them as having the same start and end angle and make a complete circle.

This forum posting has more information.

http://www.talkshopbot.com/forum/cgi-bin/discus/show.cgi?tpc=31&post=10367#POST10367

Bill