Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Signdraft on June 13, 2011, 08:16:58 PM
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Gday Guys,
We had our Matcam (Multicam) machine upgraded by CNC Teknix recently and we are just working out some bugs,
We have found that using CV mode in Mach3, optimises the motion too much causing engraving to be cut-off, but exact stop mode causes jerky movement and inconsistant engraving (See attached .JPGs)
Setting the "turn off CV mode when angle >" setting (General settings) does help,
a setting of 5 degrees = jerky movement (like Exact stop mode)
A setting of 10 degrees = "reasonable movement" - but still inconsistent engraving (As per attached JPGS)
a setting of 15 degrees = smoother movement but the "diagonal" lines are "wavy" rather than straight.
Would anyone have any ideas on how to tweak this issue out please?
Cheers
Rob.
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Hi Rob,
Curious one this.
I do a lot of laminate engraving and have never seen anything quite like it.
Because the effect is not so pronounced on the letter N where the diagonal is nearer to 45 degrees, I would suspect that the software you are using is at fault and the machine is only following the GCode it has been given.
If the individual letters were created to a higher resolution I suspect everything would be OK. Perhaps you could try the attached code (which was created using the Mach Write wizard) and report back on the result.
Tweakie.
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Hi Tweakie!
Thanks heaps for your reply mate, All assistance is greatly appreciated!
I will give your file a go and let you know how it goes!
I'm using Vectric - VCarve pro. the files were programmed in Illustrator using "Arial" font, and then I filled that contour with a V-Carve profile with a D-Cutter.
I have attached a file that we cut that displayed the anomaly. We have been engraving smaller text and it is not *SO* bad but is still not perfect!
The thing that interests me is that this machine DID engrave well when it had the Matcam controller system, but since the upgrade by CNC Teknix we've got these little gremlins to get rid of!
Looking forward to getting this sorted out :)
Thanks again!
Rob.
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Does the machine have steppers or servos? I can't believe that CV is causing those issues, as the M in "Motor Control" is made up of long straight moves, which CV would have no effect on.
If it has servos, I'm thinking it's a servo tuning issue.
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Hi Ger21,
The machine has been upgraded to Servo Drive by CNC Teknix.
We have done some "Basic" Tuning, But i think more needs to be done!
Pete from CNC Teknix is coming up as soon as he can, so hopefully he can sort this out for us :)
It seems to do fine on straight moves ( where 1 axis is moving only), but where 2 axis move together ( as in diagonal) it is "Steppy / Wavy"
I knocked the setting down from 15 degrees to 8 degrees and it has MARKEDLY improved this issue! (Enough to get away with the engraving, but not perfect!)
Thanks for your reply ger21!
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Make sure all the other CV settings are off, both in general config, and the two on the settings page (distance and feedrate).
changing the CV angle setting should have no effect on those moves, as they are single lines of g-code.
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Can you attach your xml please.
Hood
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Hi Ger,
I'll check those settings, If it turn CV mode off completely the machine is very "steppy" (each line of code has a slight pause before the next begins, which is slow on the engraving as there are so many lines of code!)
Hi Hood,
Thanks for the reply, XML Attached!
(I think this is the correct XML file as we do use the Mach 3 Mill program. This file came straight from the \mach3\Directory)
Thanks again for your help Gentlemen!
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OOOps! Forgot to add the file!
::)
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Ok your motor tuning is too fast for the kernel you have, you will need 65KHz, hopefully your computer can handle that.
Hood
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In fact your Y is even higher at over 100KHz, are you using the parallel port? If you are you are going to have to slow down on Velocity in motor tuning.
Hood
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Oh! Ok!
I'll ask Pete from CNC Teknix to look at this for me as I have little to no idea how to change that!
The computer is an Basic PC runing Windows 7, so i think it should have the capacity in my humble opinion!
Thank you greatly for your assistance!
Added: - I'm not sure how CNC Teknix have set up the outputs to the machine, I will ask Pete to check this out as a possible cause of the problems!
May i ask, Are we covering up the problem by setting the CV settings differently? I set the "Turn CV mode off on angles>" to 8 degrees this morning and it has made a massive improvement, but it is still not 100% spot on!
Many thanks again, I really appreciate the support you have all shown!
Regards
Rob.
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If you are just using the parallel port then you have the axis velocity way too high as you can not get that frequency
If you set the Velocity for X and Y axis to 6500 and Z to 2500 and the kernel to 45KHz and see how things go.
You may be able to go faster but just set these for a test.
Hood
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Thanks for this Hood!
I will ask Pete to have a look at these settings when he gets here to continue the Tuning!
I thank you greatly for giving us the lead on where to look and what to try to resolve the issue!
Regards
Rob
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I cant see how CV settings would help where you are having the issues butthen again if motor tuning and kernel are screwed up then its possible that its helping.
All of the above is of course only true if you are using the parallel port, if you are using something like the SmoothStepper then it can pulse much faster so your motor tuning may well be correct.
Hood
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Ah ok just looked in your xml and you are indeed using the SmoothStepper. I will load the same plugin you are using (17bd) and see if there are problems with your SmoothStepper config.
Hood
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Had a look at the SS config and it seems reasonable, I would however set X axis to 65KHz and Y and Z to 128KHz and the other axis to the min of 32KHz. It likely wont help with your issue but its best set that way to reduce overheads.
Hood
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Thanks Hood!
Many weeks ago we had a fault on the screen, which mentioned the smooth stepper! I cant remember the exact fault but it was a LARGE dialog box, Some of the warning dialog i had written down was:
"Smooth Stepper V17bd”
“Smooth stepper ran out of data….. blah blah blah…. You should home before proceeding……”
I will discuss this with Pete when he gets up,
Thanks again!
Rob.
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That looks like badly tuned set of servos. It will look good on lines that are inline with the axis movement EXCEPT at the tail end of the move AND on diagnal striaght lines you get the scallop effect.
Look at the end of the inline straight moves it has a BIG overun and correction. Same with the diagnal moves , move overshoot correct back.
Just athought, (;-) TP
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Hi Ger,
I'll check those settings, If it turn CV mode off completely the machine is very "steppy" (each line of code has a slight pause before the next begins, which is slow on the engraving as there are so many lines of code!)
Leave CV on, but turn off all the options.
But again, I think it's a servo issue, and Terry seems to agree.
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Thanks Gerry!
I will show Pete this thread, I'm sure we will get to the bottom of it!
Thanks again for everyone's assistance! Hopefully i will be able to report back with some good news soon!