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Author Topic: Mach3 adding extra loops in a string of arcs  (Read 11888 times)

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Offline Deano

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Mach3 adding extra loops in a string of arcs
« on: February 12, 2013, 10:54:28 AM »
Any ideas why extra "hooks and loops" show up when routing a part outline consisting of a series of arcs? I've been routing about 15 or 20 different outlines
(guitar pickguards) successfully, then suddenly a new wrinkle shows up.  Cad files are created in Flexisign, (poly line curves) exported as .dxf, to BobCad,  .dwg, cleaned up to make arcs tangential and features more dimensionally correct, then BobCam to generate gcode with Mach3 post. 
I struggled through lots of learning re. lead-ins/-outs, and issues with tool path offsets (thanks to many good forum posts as resources)
I can't see any difference in the code from other parts of the same outline. I've zoomed in on the .dxf and .dwg drawings and can see no breaks or flaws in the joining of the arc endpoints. I've tried re-starting Mach, reloading code, re-creating code.  So far, it's the only drawing to show the problem.
I hope the attached files are enough info for a clear understanding. Thanks a bunch.

Offline Tweakie.CNC

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Re: Mach3 adding extra loops in a string of arcs
« Reply #1 on: February 12, 2013, 11:52:52 AM »
Hi Deano,

I am a bit mystified - in your Mach3screenshot.doc where are the 'hooks and loops' which you are referring to please ?

Tweakie.
PEACE

Offline Deano

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Re: Mach3 adding extra loops in a string of arcs
« Reply #2 on: February 12, 2013, 01:13:02 PM »
Tweaky,
Sorry, I've been staring at that part so long I thought everyone could read my mind :D
The lower right large radius part outline is the area of interest.  The resolution is pretty poor, sorry, but if you can see the purple (actual part) is a smooth curve,
the tool path (white) is irregular.  I haven't cut material yet, just did a flyover run and noticed the extra moves, then looked closer at the tool path display to see the anomaly.

Offline Tweakie.CNC

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Re: Mach3 adding extra loops in a string of arcs
« Reply #3 on: February 13, 2013, 01:38:26 AM »
Hi Deano,

I understand now.  ;)
What you are seeing is just the tool-path display based on the available screen resolution.

In practice the machine will follow a much smoother path when your code is run.

Tweakie.
PEACE

Offline Deano

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Re: Mach3 adding extra loops in a string of arcs
« Reply #4 on: February 14, 2013, 09:00:50 PM »
Thanks for the reply, Tweakie
I just ran the gcode again on the router, did a "z axis up" flyover to verify the tool path, and still get the wierd extra moves from about line 1220 to 1300.
Also checked the Mach3 version: R3.042.040
Thanks.

Offline BR549

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Re: Mach3 adding extra loops in a string of arcs
« Reply #5 on: February 14, 2013, 11:21:11 PM »
iF you are talking about the squigglies at the lower RH corner(aboutline1220)  that appears to be a glitch in MACH3's comp code it appears the most with G3 code.

(;-) TP

Offline Deano

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Re: Mach3 adding extra loops in a string of arcs
« Reply #6 on: February 15, 2013, 08:40:29 AM »
Thanks, BR549,
So, it's not Me?  ;D
Is there a fix for that? does the latest rev. of Mach3 overcome that? I'll try that this afternoon for kicks.
I suppose if nothing else, I could skip over that section and run the cutter the other way w/ G2 arcs.  But why does it only do it on this part, this section of the outline and no others ( out of about a dozen similar part outlines)? I guess I just got lucky, eh?

On the other hand, there's a beautiful sunrise over the frozen lake this morning, life is good.  8)

Offline BR549

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Re: Mach3 adding extra loops in a string of arcs
« Reply #7 on: February 15, 2013, 10:03:13 AM »
I tried your code 7 ways to Sunday on the latest Version(;-)  Changed the leadin/ outs no luck. There is no ryhm or reason with the tool comp glitchs.

NOW I have seen a total rewrite of new code work just fine. Sometimes editors LEAVE things in the file that we do not see.

Just a thought, (;-) TP

Offline BR549

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Re: Mach3 adding extra loops in a string of arcs
« Reply #8 on: February 15, 2013, 10:42:29 AM »
I just reCamed your DXF and it  works fine with the outer profile running as Convential cutting (CCW) Tool comp behaves itself. Tired it as you had it(CW) and it still failed

Just a thought, (;-) TP

Offline Tweakie.CNC

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Re: Mach3 adding extra loops in a string of arcs
« Reply #9 on: February 16, 2013, 03:58:41 AM »
Hi Guys,

I am sorry to be an absolute pain but obviously I am missing something here.  ???

I ran the posted ‘fender jaguar.txt’ file last week and could not see any problems – could you please enlighten me on just what the problem is ?

Tweakie.   
PEACE