Z - Axis zero drifting during run

Fairly new user here. I have a MK2 30 X30 and I recently upgraded the controller from LB to SLB and I am using G-Sender 1.4.9.

I know that there have been multiple posts with this issue and I think I have tried just about all the advise given and still getting the same issue.

I have run a program a few times and the same thing seems to keep happening. About 1/3 into the program the Z axis zero starts to drift lower. And after running a job about 12 inches in length the Z zero changes by almost 0.25 inch down.

Things that I have tried.

  • Checked the bit hasn’t moved out of the collet. I measured the amount sticking out before and after and it hasn’t changed.
  • Set Firmware 37 to on for Z axis
  • Firmware 212 is set to “35”
  • Firmware 1 is set to “255”
  • Z axis stepper motor connection stayed connected through out.
    I ran the program and then stopped it when I noticed it doing dropping down. At this point I set 1 to 255 and re-zeroed and started the program again. It again followed the exact same profile as was previously cut.

I thought upgrading to the SLB would help solve issues but It appears to have caused more issues. I wasn’t having this problem before.

Dallas

@DallasD.Woodworks I had similar issues and also tried every suggestion I could find in these forums to no avail. I recalled reading about the changes in the SLB and firmware that they changed microstepping from 8 on the original longboard to 32. On a hunch I reverted back to 8 and seems to be working as expected now.

Seee this thread for the full discussion: Can SLB drive a stronger Nema 23 Stepper Motor? - SuperLongBoard / :question:Question - Sienci Community Forum

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@DallasD.Woodworks @aarseneault may have your solution. I wonder what the effect is of using both $212 and $1. The tech manual for the SLB specifically says not to use $1=255 with that board. Have you tried without that setting?

Edit: What router/spindle are you running?

@gwilki After the issue fist came up I tried just $37 and $212. When that didn’t work I also tried $1=255.

Currently I am only running with the Makita Router. I am surprised I am getting this as this tends to only be an issue when switching to a heavier spindle.

I am currently trying a run after adjusting the micro stepping back to 8 for the Z axis.

@aarseneault I reverted the microstepping for the Z Axis back to 8 and ran a program without any stock and it didn’t drop the z axis zero this times.
I will be running it with stock to confirm but I believe this seems to have fixed my problems. Thanks.

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@DallasD.Woodworks great news. We can also try a microstepping of 16 to gain some of the benefits but not lose all the torque. I have not experimented on that yet but may at some point.

@chrismakesstuff here is another incident where he had to go back to a microstepping of 8 to prevent z axis dropping.

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When I took microstepping back to 8, the Z would not move. It made a loud noise but no movement. Is there anothet setting I need to change in order to reduce the microstep. My Z is also dropping - LMMK2 with scienci spindle.

There are 2 settings to change for each axis. Microstepping ($152) to 8 and Resolution ($102) to 200 for the z axis.

I have changed these for x, y, and z. I never tried changing a single axis.

Ok. Thank you. I will try this

Thank you so much. That worked. Hopefully I can keep using my spindle now. I assume if I want to try 1/16 step later on, I would raise resolution to 400

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Great news @lilmain98 .

Yes for 1/16 microstepping you would have to set the resolution to 400

So I ran a job today and had no drop in the Z axis. I hope this fixes it.

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