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rounded off corners
« on: May 07, 2011, 01:20:51 AM »
I have some issues with rounded off corners.  It doesn't seem to matter whether they are internal or external.  I read through the forums and someone mentioned during on some angle thing.  (something to do with 89 degrees)  I can't seem to find it right now, but I did so and I though that solved the issue.  However it popped up again and cut some corners that I didn't intend of having cut. 

Ideas?

Offline Hood

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Re: rounded off corners
« Reply #1 on: May 07, 2011, 03:53:21 AM »
If your acceleration is slow and yur code is in G64 mode (Constant Velocity) then you may suffer from corner rounding. First thing to test is put Mach in G61 mode (Exact Stop) and if that cures it then you have found the problem. Remember to check your code to make sure that any G64's are replaced with G61 as even if you default Mach to G61 the code will override it if it has a G64.
 If that cures the problem then you can again try with G64 but this time mess around with the CV settings on General Config page to see if you can improve things.
Hood

Offline stirling

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Re: rounded off corners
« Reply #2 on: May 07, 2011, 09:58:10 AM »
JFYI be aware that not all of the posts re: 89 degrees are neccessarily stil valid depending on what you're trying to achieve. Mach changed at some point in the way this angle is specified - it used to be "stop CV on angles <" and now is "stop CV on angles >". Some posts are with reference to the "old" way. Also, the section entitled "Stop CV on angles > _____Degrees" in the current "Mach3 CV notes" is incorrect.

Ian
Re: rounded off corners
« Reply #3 on: May 07, 2011, 11:56:47 AM »
Hi,

I "roll the cutter" around external corners, it's softer on the mechanics and better accuracy when in CV mode.
ATB
Derek
You can "chop it off" but can't "chop it on"

Offline ger21

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Re: rounded off corners
« Reply #4 on: May 07, 2011, 12:03:38 PM »
Using G41/G2 will also "roll around" corners.
Gerry

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Re: rounded off corners
« Reply #5 on: May 08, 2011, 12:11:50 AM »
What's incorrect about the Mach 3 CV notes?
Re: rounded off corners
« Reply #6 on: May 08, 2011, 02:04:51 AM »
We just got our CNC Router and also getting rounded corners in CV mode. ES cuts perfectly but takes a lot longer. It's the first time we are using Mach3.

Offline stirling

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Re: rounded off corners
« Reply #7 on: May 08, 2011, 05:25:21 AM »
What's incorrect about the Mach 3 CV notes?
I raised this about 4 years ago but can't seem to find where. See attached where I've edited the paragraph.

Ian
Re: rounded off corners
« Reply #8 on: May 10, 2011, 01:33:51 AM »
CV Turned on with a 0.01mm distance tolerances seem to be the answer if you looking for faster engraving and sacrificing as little as possible accuracy. I also read that a "smooth stepper" might help?

I've been reading as much as I can since I joined , I did read that one person say that a weak servo motor might also be the cuz for the jaggedness when engraving a arc at high speed, any truth in that? We have a Delta b series .75kw ac servo drives [comes with encoders fitted]  or possibly that "his" machine was to flimsy, our machine is 1.2tons so it's not flimsy i think..

Offline Chaoticone

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Re: rounded off corners
« Reply #9 on: January 12, 2012, 05:47:35 PM »
Quote
I raised this about 4 years ago but can't seem to find where. See attached where I've edited the paragraph.


Sorry I missed this Ian, I'll edit the doc. to reflect your findings.

Brett
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