Author Topic: Having a small problem with mach3  (Read 8836 times)

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Offline Briancnc

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Having a small problem with mach3
« on: November 10, 2008, 08:54:12 PM »
Well this originated from a vectric forum thread but it seems the problem isn't in the vcarvepro file its in the post processor or the gcode/settings I have in mach3. It's two part, one that the pockets aren't complete and they are cut weird and all the same way. Second there are knicks or bumps at the end of each corner, like it took almost 1/16" about 1" long off the edge of each of the parts.

I stopped the program after the two parts cutout on the bottom so I could rectify the pockets without rerunning the entire program. Anyone have any idea what's going on? I attached screens pics and the tap gcode file. Thanks!

http://vi01.com/cnc/mach/4thaxispartsUPDATED.tap gcode file (gcode ATC post processor from vcarvepro)












Offline RICH

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Re: Having a small problem with mach3
« Reply #1 on: November 10, 2008, 09:25:32 PM »
Briancnc,
Does your CAD file look like this?
Note the small straight line segments for the curves.
RICH

Offline Briancnc

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Re: Having a small problem with mach3
« Reply #2 on: November 10, 2008, 09:56:50 PM »
My cad file doesn't look like that, that's a gcode generated by VcarvePro out of a gcode post in that program. Even if there are those little line segments that doesn't explain the little pocketing anomaly nor the little nips towards the corners. But appreciate you looking at the gcode.

Offline RICH

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Re: Having a small problem with mach3
« Reply #3 on: November 11, 2008, 07:01:43 AM »
Briancnc,
Early and need to get to work, but, i wanted to see if there was something in the code which did the offset your getting. Have some other thought's but need to get going.
RICH

Offline Briancnc

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Re: Having a small problem with mach3
« Reply #4 on: November 11, 2008, 07:57:33 PM »
Thanks Rich.

Recut tonight with mach3 arcs atc gcode post as usual (this is the PP I have been using since I have been using vcarve and mach3, probably more than 2 years now) and it ran the same. Also note in the pics its just a random pocket path, also check out those stepdown marks and how it cut those sharp corners and made them round even though vcarve prview shows them sharp.

Really strange, never seen this before on my machine.







Offline ger21

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Re: Having a small problem with mach3
« Reply #5 on: November 11, 2008, 08:37:48 PM »
Turn off all the CV options, both on the settings page and in the general config page. But leave CV on. If it's still the same, turn CV off and try it.
Gerry

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Offline RICH

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Re: Having a small problem with mach3
« Reply #6 on: November 11, 2008, 10:26:56 PM »
Braincnc,
You may want to take a look in documentation "Mach 3 CV notes".
Also just try something with equivilant cuts using Exact Stop and compare the cutting. It will be jerky going around the corners because of all the straight lines you have instead a smooth arc. Particle board ( particularly cabinet grade) has some darn hard stuff in it, such that it seemed it's possible to push back should there be any play or backlash. Additionaly, if the router assembly isn't solid you can get some spring back when say if the axis is slowing down and the cutter has more time in an area. Also saw what looked like a soft spot in the one corner and that could even contribute more to it. Have you played around with lesser depth of cuts? ie; get the accuracy you want first and then best speed will come.
Rather than making dust, use a pencil in the non working router / no z moves  to trace around see how the profiles are  under no cutting pressure.  First step would be elimination of any Mach settings as already posted and then some playing around on your part to see what works.
Just some suggestions,
RICH


Offline Briancnc

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Re: Having a small problem with mach3
« Reply #7 on: November 11, 2008, 10:46:37 PM »
Gerry and Rich thanks for your replies. I will look into the CV settings tomorrow hopefully I can narrow it down. I just haven't had a problem with this setup in mach3 before; that's what got me. Maybe I inadvertently turned something on? will have to check. Thanks so much.

Offline Briancnc

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Re: Having a small problem with mach3
« Reply #8 on: November 12, 2008, 03:34:31 PM »
Ger I have nothing on the settings page on for cv if any at all, neither in the gen config either but it is green lit in the CV mode (not dwell). Rich I'm not sure its necessary to test with a pencil, I know the feeds and speeds this machine can do; I mean I have cut quite a bit with this machine before with no problems. And frankly I haven't changed any of the settings. It's just strange because one; it shows in my vcarve preview that it's perfect, it shows in my mach preview that it is cutting normal yet it doesn't. There's just no consistency to it really; it will cut fine in certain areas and weird in the same type of area elsewhere. Sometimes I think these machines take a mind of their own.


Offline Briancnc

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Re: Having a small problem with mach3
« Reply #9 on: November 12, 2008, 03:45:44 PM »
Well I just investigated further. Check out how it deviates from the programmed toolpath. Wow, what could cause that? Never seen mach color outside the lines! lol