Need Help! CNC ESD problem? Z axis randomly shifts lower than projected tool paths


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Thread: CNC ESD problem? Z axis randomly shifts lower than projected tool paths

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    Member KT88saturate's Avatar
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    Default CNC ESD problem? Z axis randomly shifts lower than projected tool paths

    I have a camaster stinger 1 that is about 6 months old that keeps digging into the model portion of the stock. It doesn't do it right away, but eventually a tool path will go too low. What's weird is when I double check the Z the machine still has the same margin it did before, so it doesn't seem to be a persisting issue.

    I am generating the GCode from fusion 360 using the included pp. When I preview it in an external G-Code editor, it looks fine. The simulation in Fusion360 looks good as well.

    I am assuming I have some sort of ESD issue to do with my dust collector that is right next to the machine. I am using a harbor freight dust collector with 4" vinyl hoses that attack to the z axis. I wonder if its somehow disrupting the servo location?

    This issue ONLY happens on the Z axis. Is there a procedure for proper ESD grounding anywhere? I wrapped a wire from the chassis of the dust collector around the hose to the ceiling, but it stops short of contact with the machine.

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    Default Re: CNC ESD problem? Z axis randomly shifts lower than projected tool paths

    Quote Originally Posted by KT88saturate View Post
    I have a camaster stinger 1 that is about 6 months old that keeps digging into the model portion of the stock. It doesn't do it right away, but eventually a tool path will go too low. What's weird is when I double check the Z the machine still has the same margin it did before, so it doesn't seem to be a persisting issue.

    I am generating the GCode from fusion 360 using the included pp. When I preview it in an external G-Code editor, it looks fine. The simulation in Fusion360 looks good as well.

    I am assuming I have some sort of ESD issue to do with my dust collector that is right next to the machine. I am using a harbor freight dust collector with 4" vinyl hoses that attack to the z axis. I wonder if its somehow disrupting the servo location?

    This issue ONLY happens on the Z axis. Is there a procedure for proper ESD grounding anywhere? I wrapped a wire from the chassis of the dust collector around the hose to the ceiling, but it stops short of contact with the machine.
    I went through a similar z-shift down issue over the winter(with a Laguna Swift). After checking alignment multiple times (no issues), checking Gcode (no issues) and running the jobs multiple times, one of the big clues was that downward shift occurred in the same exact place on on multi-pass toolpaths every time.* One commentator ruminated about a math error in the firmware and that headed down the firmware replacement route. It turned out to be a firmware corruption issue. I loaded updated firmware and the problem went away.

    I work in a rural area with not-so-great utility service and we had had a couple of "service interruptions" around that same time. My guess is that one of them toasted the firmware.

    * I should add that I ran multiple multi-pass jobs and by "exact same place" I don't mean that at the same X-Y-Z location on the machine, I mean the same place on each job's tool path, but a differency location on the machine itself.

    Last edited by MillAlien; 07-22-2021 at 06:11 PM.


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    Member KT88saturate's Avatar
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    Default Re: CNC ESD problem? Z axis randomly shifts lower than projected tool paths

    Quote Originally Posted by MillAlien View Post
    I went through a similar z-shift down issue over the winter(with a Laguna Swift). After checking alignment multiple times (no issues), checking Gcode (no issues) and running the jobs multiple times, one of the big clues was that downward shift occurred in the same exact place on on multi-pass toolpaths every time.* One commentator ruminated about a math error in the firmware and that headed down the firmware replacement route. It turned out to be a firmware corruption issue. I loaded updated firmware and the problem went away.

    I work in a rural area with not-so-great utility service and we had had a couple of "service interruptions" around that same time. My guess is that one of them toasted the firmware.

    * I should add that I ran multiple multi-pass jobs and by "exact same place" I don't mean that at the same X-Y-Z location on the machine, I mean the same place on each job's tool path, but a differency location on the machine itself.
    Oh buddy that must have been interesting to work out. In this case, the shift only happened on one "arc", but not the rest. I am really hoping its just esd.



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    Default Re: CNC ESD problem? Z axis randomly shifts lower than projected tool paths

    I don't think ESD is the right term, electro magnetic pulse is what I would (and have) called it. It might come from static electricity, but the magnetic pulse is what propagates the issue to another wire.

    Where are, and what type are, your motors and drivers?

    I had a CNT motion systems machine in the past, that developed an intermittent short on the spindle cooling fan... similar to switching a dust collector on and off but probably less power (maybe higher voltage, v220 if I recall).

    However, it was only a problem because the fan wiring ran beside the step and direction single wires which needed to get to the gantry. After that point it went to closed loop servo drives (mounted to gantry) but with no feedback to the PC control.

    The fan short would move one of the two Y axis motors in my case, eventually causing the system to fault from the torsion of one side of the gantry out of alignment.

    Took years to figure out.

    But, very hard to happen if you have closed loop motors and drivers in a cabinet, as my current Chinese router does. But, if I recall, your machine has a cabinet below the table. I would check the wiring BEFORE that cabinet first, although if the motors are open loop it probably could be after the cabinet......in that case I'd think about swapping in a closed loop stepper and driver which should be able to correct for such things, even if it was the dust collector.

    Sent from my Nokia 3.4 using Tapatalk



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    Default Re: CNC ESD problem? Z axis randomly shifts lower than projected tool paths

    For follow up,

    this was just esd.

    It was solved by running a copper wire INSIDE and OUTSIDE/around the dust collector hose. The hose is vinyl, which is not helping I am sure. I ground to the dust collector and the gantry.

    I haven't seen a z discrepancy again.

    Quote Originally Posted by gfacer View Post
    I don't think ESD is the right term, electro magnetic pulse is what I would (and have) called it. It might come from static electricity, but the magnetic pulse is what propagates the issue to another wire.

    Where are, and what type are, your motors and drivers?

    I had a CNT motion systems machine in the past, that developed an intermittent short on the spindle cooling fan... similar to switching a dust collector on and off but probably less power (maybe higher voltage, v220 if I recall).

    However, it was only a problem because the fan wiring ran beside the step and direction single wires which needed to get to the gantry. After that point it went to closed loop servo drives (mounted to gantry) but with no feedback to the PC control.

    The fan short would move one of the two Y axis motors in my case, eventually causing the system to fault from the torsion of one side of the gantry out of alignment.

    Took years to figure out.

    But, very hard to happen if you have closed loop motors and drivers in a cabinet, as my current Chinese router does. But, if I recall, your machine has a cabinet below the table. I would check the wiring BEFORE that cabinet first, although if the motors are open loop it probably could be after the cabinet......in that case I'd think about swapping in a closed loop stepper and driver which should be able to correct for such things, even if it was the dust collector.

    Sent from my Nokia 3.4 using Tapatalk
    Sure, its the discharge that causes it to alternate and propagate. That's fair but it builds up due to static. If we can stop the cause then we're good to go so I elect to keep everything at the same potential.



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CNC ESD problem? Z axis randomly shifts lower than projected tool paths

CNC ESD problem? Z axis randomly shifts lower than projected tool paths