VCarve issue with Mach3

VCarve issue with Mach3

Postby Fab6657 » Tue Apr 24, 2012 6:33 am

Hello All's,

first of all apollogize my english, i am not native english speaker.

I want to send a help in the communitie, because a friend of me
and myself are searching since a long time an issue we have
with vcarving text.

We use Mach3 with 2 different CNC (one from BZT, the other one from EAS)
Paralell port interface. He have the problem, i have not the problem.

I attach the picture with the issue, at same text position, the vcarve
go deeper and deeper. Mention that this happen only with vcarving
not with pocketing normally !

It seems that the Z axe loose steps at retract, but always in the same
way. If you mill twice or more, you have the same result in text.

Have somebody this problem and the solution ? We will be crazy :)

We tried lots of Mach3 version from 2.63 to last lockdown.

Anyway, think's for helping.

PS : i attach the picture, the g-code file (from VCarve) and the Mach3
config file.

Fabrice
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Problem Pierrot.zip
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Re: VCarve issue with Mach3

Postby Greolt » Tue Apr 24, 2012 8:01 am

Looking at the code, the Z axis rapids when retracting between cuts (fast) and then plunges at feed speed.(slower)

Best guess is that the Z axis is loosing steps when retracting.

Try lowering Z axis rapid speed and acceleration.

Greg
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Re: VCarve issue with Mach3

Postby zeeway » Tue Apr 24, 2012 2:25 pm

I presume you have checked to ensure all mechanical connections, such as couplings, are tight, and that your have minimal backlash. When all that has been checked, consider this:

The voltage signal coming out of the parallel port of desktop machines must be consistent and strong enough to drive your machine controller. Some desktops have an issue in this area. This can cause lost steps on any axis, but it usually shows up mostly in the Z axis, since there are usually many more Z moves.

I had this problem several years ago on my first machine. I tried a separate printer card with a parallel port - this did not work for me. My problem was solved when I installed a SmoothStepper board in my desktop - that replaced the parallel port connection.

Good luck,

Angie
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Re: VCarve issue with Mach3

Postby davewierenga » Tue Apr 24, 2012 4:11 pm

I too had a similar problem that was solved by lowering the aceleration and speed of the z axis
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Re: VCarve issue with Mach3

Postby Fab6657 » Tue Apr 24, 2012 8:27 pm

Hello,

thanks for first hints. We try to reduce the axe speed,
but may be not enough.

So we will reduce to a really slowly speed for Z like
300mm/min.

I will give you feedback after tests.

PS: we have a intermediate breakboard card with
buffer and try with 2 different desktop PC.
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Re: VCarve issue with Mach3

Postby Greolt » Tue Apr 24, 2012 11:35 pm

Fab6657 wrote:So we will reduce to a really slowly speed for Z like
300mm/min.

Don't forget the acceleration. Possibly more important in this test.

Greg
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Re: VCarve issue with Mach3

Postby Fab6657 » Wed Apr 25, 2012 4:41 am

Hello Greg,

thanks for the remark, we will first test the acceleration and see what happen !

Fabrice
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Re: VCarve issue with Mach3

Postby Fab6657 » Thu Apr 26, 2012 7:24 pm

Hello,

we try different speed and acceleration,
really slow from 300mm/min to 100,
and always same result, not good.

The result have the same pattern,
Z go deeper and deeper at same
X, Y coordinate.

If you have an idea, thank's

Fabrice
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Re: VCarve issue with Mach3

Postby zeeway » Fri Apr 27, 2012 11:43 am

Try a SmoothStepper board...

Angie
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