Depth Cut per pass Changes Mid Carve

Hello, I am experiencing an issue where the depth of my cut per pass changes drastically mid project. For instance I am working on this project ( I set the depth cut per pass at .025 because the default of .05 broke one of my bits. However I noticed that the carve was being more aggressive from the sound. It looks like it is carving the full .125 depth in one pass. This also results in carving through sections on the face of the project that aren’t supposed to be cut, as if the z-axis isn’t raising up high enough to clear the material as it moves.

Has any one else experienced this issue? I couldn’t find any forum posts related. Is it software based? I have the newest firmware installed, and I am using the https easel as recommended.

Thanks in advance,

Did the bit retract to the same start position? (minus the safety heigh)
If so, the error is in the code.

If not, its probably mechanical or electrical.
If one of the four Z stepper wires have poor / no contact the stepper will move as normal but without directional control => typically want to move in the direction of least resistance (down).

Another likely possibility is that the stepper stalled during a retraction, causing the next “down” to go beyond intended level. A stalled stepper will make a grinding sound.

Your Easel-file do not show any reason for the anomaly.

When I cancelled the carve the bit did return to the correct home position without causing any issues. The machine did sound a little off this morning when I was running it. How do I A) Confirm that the stepper motor is the issue? B) fix a stalled stepper motor? & C) prevent it from happening again? I have run into this problem, once before on another project, but no longer have the file for that one.

After the cancel, did you re-home (homing switches) the machine? If so its re-synced itself to your workspace as work zero is stored as an offset from machine zero

To test for A:
Make a mark of a reference point for your work zero so you can verify it will return to same position after a carve.
Make an operation with frequent up/down motion and run an “air carve” (router off, in air)
Stress test your machine.

Stalled stepper = it had insufficient torque available to successfully make the motion. Check anything mechanical for friction etc. I assume you run a stock Z-assembly / feed rate / acceleration values?

C: Depends on the above

It returned to the zero I set up for that particular carve, not the machine 0/0, so no homing switches were triggered.

I will check all of the motors and clean them as best I can without completely disassembling. Yes tot he stock Z-assembly / feed rate / acceleration values.

Thanks for walking me through this, I appreciate the help!