In the middle of a cut the laser head reached the end of the upper limit on the y-axis and then when it resumed cutting it was as if there was no y movement - the cut was just a slightly wiggly line in the x-axis. Running a test on a simple circle resulted in it cutting an s shape. Any ideas?
Either loose belt or pinion gear is not properly secured to the shaft for the Y axis.
Thanks I’ve tightenned the belt and the problem still occurs. I can’t see any way of securing the pinion gear - is it feasible that this has worn away from the motor shaft?
The pinion gear doesn’t appear loose either. I can move the head around occasionally and have cut some simple square shapes but anything more complicated results in either the wiggly line or a random shape. Using this manual jog arrows I can move the head along the x-axis but not along the y-axis - it just judders and stays in one place.
I’ve never seen a pinion gear that was machined with the shaft. These are almost universally secured using grub screws that attach either at the base of the pinion gear closer to the stepper motor or through the teeth themselves. Look for a small hole that would accept a grub screw and hex wrench.
no, nothing there.
How are you examining this? Have you taken the belt off the gear? If it’s an easy process I suggest you do so in order to examine it closely.
If it’s hard to do take off then belt, then I suggest you try testing before disassembling. Try lightly resisting motion along the Y with the motor engaged. Can you see either the belt or gear slipping? If you can confirm, then remove the belt and examine for where you saw the slipping.
I’ve taken the belt off and removed the motor from the supporting armature. There’s no sign of any securing device for the pinion. I’ll try applying resistance once I’ve reassembled the machine.
While you have it off the machine, you may want to test jogging up and down. Can you confirm that the stepper moves in opposite directions while jogging up vs down?
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No. When I jog up and down the stepper moves erratically and never more than 10 degrees or so. There seems to be no correlation between the direction I move it and the rotation of the stepper.
If I ‘Home’ the laser head then the stepper rotates fully. If hold the pinion gear while doing this the gear and shaft remain stationary
Try swapping cables for X and Y at the motor ends. Does the problem stay with the motor or change motors?
Then go back to original configuration but then switch X and Y cable at the controller end. Does the problem stay with the motor or change motors?
I’ve plugged the X-cable into the Y-axis motor and the motor responds correctly to the jog inputs (The configuration of the P7 is such that I can’t easily connect the X-motor to the Y-cable). When I recconect the Y-cable to the Y-axis motor the original problem remains
Okay. So you’ve ruled out the Y motor as the problem.
The trick now is to isolate if the issue is at the controller or in the Y cable.
Can you swap X and Y cable at controller and test?
Unfortunately not - the cable connectors are a different size where they meet the controller
Do you have a meter that you can use to test the cables for continuity? You want to make sure that every wire has proper continuity end to end.
I’d suggest a physical examination as well to see if you can identify any visual damage to the cable or control board.
Also, if you take a close look at the cables on the controller side is it possible that one is just a superset of the other? Meaning you could plug in the smaller cable into a portion of the header for the other cable? Don’t do this unless you can verify the pinout.
I don’t have a meter but could get one. The design of the P7 means that its not possible to detach the cables at the controller side, there are a couple of spare cable entries but I can’t verify that these are the same as the motor cables. I’ve checked over all the cables and the as much as I can see of the controller circuitry and there’s no sign of obvious damage.
They’ve certainly made it difficult to troubleshoot. If I had to guess it sounds like to me that the stepper driver on the board may have gone bad but purely speculating.
Are you also in contact with Atomstack support? They may have some insight from a common failures perspective on that machine.
I have messaged Atomstack but not received a response yet. I think you are right and its an issue with the driver. I wanted to exclude the possibility that it was a sudden software incompatability. Thanks for all your help.
Since it’s something you can recreate with jogging controls alone it seems unlikely.