Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: Sambonnie on February 28, 2013, 06:32:14 AM
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Hi Guys hope all is well?
Basically i have a cnc over head router,
one of the 2 drives that runs the x axis blew up so got a replacement and swaped it for the y. ( the x runs on 2 motors and the Y on one)
all fitted and working but the new drive i beleive needs some motor tuning through mach.
if i cut a square it cuts the 2 corners off please look at attachment to see.
can you help?
regards Tom
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the white line is what i want to cut,
the red is what its doing
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Cant see it being a Mach issue if it was ok before, more likely the drive itself needing tuned, assuming of course its servos, which I think it is ;)
Hood
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hi hood thanks for reply, i dont beleive it is mach either the new drive is of different firmware so i have set it up as good as i can mirroring the originals. I know that mach has motor tuning will tweeking that help?
thank you again for your time
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i use artcam 2010 and v carve. V Carve has a fuction calles square corners which stops it cutting the red corners of but... when cutting circles it makes them not round and that is the main problem im trying to sort
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Machs tuning will not help as it could only be the steps per unit were incorrect and if that was the case then the Y would be shorter or longer than it is meant to be. From what you are saying it looks like the axis is eventually getting on position but that it is slow to respond and Mach will have no effect on that as that is a function of the servo drives tuning.
The only possible things in Mach that I can think of that could affect things is possibly the Step active state is wrong for your drive but that seems unlikely with such a large discrepency.
Regarding ArtCAM, I am not sure how it could correct for that, if it was corner rounding then I could see it but seems to be a straight line at the corners that you are seeing.
Hood
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ok cheers hood wasnt the answer i wanted to hear, but at least i know the faults now thank you for your time :)
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Have you tried swapping one of the X for the Y?
Does the Y now behave and X axis skew?
Hood
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honest aswer is that the x axis runs on 2 motors so i dont want to set it to bend the boom out of square if you know what i mean
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Thats what I was wondering, whether it would skew the gantry, dont think you would bend it if its the machine I am thinking it is ;)
Hood
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it woudnlt bent it tbh it would knock it all out of square worst case would snap 8 bolts holding boom to where the motors go,
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Dont think your servos would be powerful enough for that but just some low motion relatively short moves would show it up.
I think the problem would follow the drive as it does seem to me to be a tuning or drive issue.
If not wanting to do that, can you monitor the position from the drives software on another computer or possibly it has a scope in the software that you can use in manual tuning mode. You could then look at the response of the moves the drive is making whilst in the manual tuning mode, maybe even compare to another axis. I think things are over damped and you are just not getting the axis on track soon enough at the end of a move.
Hood
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I kno the servos are strong enough to snap 8 bolts easily, we have a vacuum pump and on a full sheet it works out to about 4tonne holding the sheet down, and i have seen the motors on the x push the sheet striaght off in the past 8 x m12 aint going to stand that imo lol.
I have garry at zapp automation seeing if he can send us the firmware update for older drives to match the firmware to new drive
thanks again Hood