JUMPS WHEN CUTTING

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weldguy
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Re: JUMPS WHEN CUTTING

Post by weldguy »

OK so you see the problem on one side, that's a good start. Lets keep this simple. So what I would do next is plug the left motor in the right driver and right motor into the left driver. Your gantry will move in the opposite direction you would expect it to but that's ok for testing. Did the problem move to the other side of the machine?
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Re: JUMPS WHEN CUTTING

Post by acourtjester »

Are you using timing belts and pulleys to driver your axis, if the pulleys are not is exact alignment you will get a jump. the belt seems to climb and then the axis jumps. As Weldguy is saying substitution some time is better troubleshooting as the problem moves or follows a part. If it does not move then it is some other thing. You could have a problem where the rails are not perpendicular, you could disconnect the drive motors and manually move the axis to see it there is a bind anywhere.
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Re: JUMPS WHEN CUTTING

Post by tcaudle »

One of the ways we use in the lab to narrow down an issue like this is to pull the moors (XY and Y2 ) . Make yourself some round discs or get some larger pulleys that fit the shafts. Put marks on t he disc as a reference. get a board and clamp the motors down to it and point the shafts out and Align each motor shaft with the marks at 12 o'clock. Power everything up and zero each axis.in software. With the marks all at 12 0'clock the DRo;s should all read 0.000,

Write yourself a piece of "torture" code hat sends each axis out a distance and a different speed . do combined moves but always bring then back to zero each time. The dual motors with turn opposite but should both always end up back at 12 o'clock on a return to zero. zero. A file that does not of different length moves at different speeds (G1 moves with an F call) and rapid returns (G0 XY 0 ) . If the marks always line up you can eliminate the motors, control , cables. and drives. A that point its mechanical.

If you can't write the code let me know and I can post test code we use the verify lost steps. While being under exceffive load can cause lost steps that is a mechanical issue. Steppers do not get "weak". A defective driver could be pulsing at reduced current BUT highly unlikely and can be confirmed by swapping drivers.

Once you convince yourself it's not the electronics causing it (or if it is it will be obvious) then you can focus on what it really is.

90% of the time this is mechanical. Something is slipping. You can tighten set screws until you are blue in the face and still have backlash and slippage. There is a LOT of torque in a small area .

turn your motors on so they lock and go to each one (each end of the gantry) and try (hard) to move it back and forth. If it moves at all in either direction then start looking at the components and see which is moving and which is not.
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Re: JUMPS WHEN CUTTING

Post by kennye »

I finally fixed my problem { by mistake] I had 2 drivers that went bad and I replaced them now everything seems to be on time
is it possible that the drivers were causing it to screw up? I wanted to post this in case somebody else were having this problem .Thanks everyone for all the help.
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Re: JUMPS WHEN CUTTING

Post by tcaudle »

Drivers, motors. cables, Tuning. loose gears/pulleys, bad bearings, settings, earth wobble.....replacing everything is one method (aka "shotgun method")
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Re: JUMPS WHEN CUTTING

Post by kennye »

Amen that I did. lol
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Re: JUMPS WHEN CUTTING

Post by acourtjester »

Congrats it always helps when you can put a finger on what was causing the problem
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weldguy
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Re: JUMPS WHEN CUTTING

Post by weldguy »

Awesome, glad you got it solved. Certainly sounded like a driver issue :Like :Like
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Re: JUMPS WHEN CUTTING

Post by bucksur »

it has a lpt port and I am running mach3.It like it gets hung up and then jerks forward.
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Re: JUMPS WHEN CUTTING

Post by adbuch »

kennye wrote: Sun Jul 25, 2021 10:18 am
is it possible that the drivers were causing it to screw up?
Yes. If you want to confirm this, try installing your "bad" drivers back in to your system and see what happens.

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Re: JUMPS WHEN CUTTING

Post by bucksur »

bucksur wrote: Sat Aug 28, 2021 8:32 am it has a lpt port and I am running mach3.It like it gets hung up and then jerks forward. surveyzop
not very much but just enough to screw up my piece.
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Re: JUMPS WHEN CUTTING

Post by adbuch »

bucksur wrote: Mon Aug 30, 2021 1:05 pm
bucksur wrote: Sat Aug 28, 2021 8:32 am it has a lpt port and I am running mach3.It like it gets hung up and then jerks forward. surveyzop
not very much but just enough to screw up my piece.
????? Please elaborate.
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kennye
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Re: JUMPS WHEN CUTTING

Post by kennye »

Sorry I just seen this post I had the same problem make sure your drivers are set the same .My drivers were showing good even tho they were bad I went every possible avenue to get it cutting right but the drivers finally quit that's what made me change them and it cured my problem .Now your problem may be different but that fixed mine.
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