Z Axis loosing position

[FBWoodcraft]

I have an issue with the Z axis changing. At first I determined I had a problem with motor connections since I’m using an SLB to control my OneFinity and was trying to use molex connectors to connect to the 1F cables. That proved to be ineffective. I ended up using an aviation connector for the Z axis connected directly to the SLB connection. All axis jog properly now.
After Setting Z 0, I can jog Z up and down multiple times and Z 0 stays the same.
Z doesn’t retain it’s position during or following a cut.
I’ve checked the couplers and ball screw on the Z axis and tightened everything.
What happens is after setting up a job and Z is zeroed I can raise it and the goto Z 0 and it checks good.
The first instance of the problem occurred trying to cut a house number sign, it starts ok, but starts cutting deeper as it goes.
I created a test file using a 30" circle and 120 VBit cut to 0.1" to test all axis. It runs the file and ends without issue. However, immediately following and I goto Z 0, it goes slightly deeper though the MC position doesn’t change. The X & Y will run the same cut without deviation.
At this point I think I’ve eleminated mechanical possibilities, wiring connections show 0 resistance, so I’m at a loss as to what to look at next.

Appreciate any help you can give.
Bruce Hudson
Fallen Branch Woodcraft
brhudson98@gmail.com
270-993-6658

1. Firmware version:
2. Sender: 1.4.7
3. Relevant tested files: (upload files here using the upload button)
   Address_2-Number 120 VBit.gcode (42.3 KB)
   Cal Circle 120 VBit.gcode (397 Bytes)
4. Any pictures or videos attached showing the issue:
   
   
5. Upload of the ‘Diagnostics’ PDF file: diagnostics_6-7-2024_14-50-07.pdf (107.2 KB)

Steps to reproduce:

1. Run the address file

[Lappa]

Are you sure the bit isn’t moving in the collet?

[jpnharris]

You might try setting 37 z-axis hold to on and change 212 to 10% in case this is z-axis drift due to weight.

[FBWoodcraft]

Sure would be nice for those of us using the SLB for non Scienci machines to have a descriptive guide to all the firmware settings, or maybe there is but I just haven’t found it.

Thanks for the tip on the firmware 37 setting. It didn’t help my Z axis problem, but I did find that it was set to On for the Y axis which was causing Y to go out of sync at higher travel speeds, which stopped after turning it off. Although I did still have to lower 121 acceleration to 500, I had to have it at 350 before turning 37 off. Not sure exactly why 37 was on for Y.

In touch with 1F support (very responsive, even on weekends) on it, and it’s looking like it may be the ball nut bearing.

Bruce