[cnc Rookie]

Boss 6 control...original electronics

What would cause the Z to drift down when running a program?
The DRO doesn't move (drift) but the shell mill cutter did. So I know the bit did not slip in the holder. Very strange.

I was just bragging how well it was working. Forgot to knock on wood :strange:

[cncmakers001]

Boss 6 control...original electronics

What would cause the Z to drift down when running a program?
The DRO doesn't move (drift) but the shell mill cutter did. So I know the bit did not slip in the holder. Very strange.

I was just bragging how well it was working. Forgot to knock on wood :strange:

There could be some backlash or wear in the Z-axis ball screw or lead screw.
If the nut or screw isn’t holding steady, it might cause the movement to “creep” without affecting the DRO.

[cnc Rookie]

You may be on to something here.
I am opening the Z ballscrew cabinet and going to do an intervention today.

[cnc Rookie]

I opened the Z cabinet and had a look around. The belt looked fine. Still had good tension. The teeth all looked in great shape. Manually moved the quill up and down stopping every so often and checking for any slop. Notta. The ball screw looked good. Nice and clean with a little oil on it. Just couldn't find anything out of the ordinary. Put it all back together and run a couple tests. Checked out AOK.

For the life of me I have no idea what happened. I input one command on the MDI for the X to move. Not the Z. But for some unknown reason the Z gods were against me.
Everything seems fine now.

[awerby]

The tool might be slipping in its collet - that wouldn't affect the DRO either.

[cnc Rookie]

The tool might be slipping in its collet - that wouldn't affect the DRO either.

It was shell mill in a kwik switch 200 holder. I possibly put the tool in the mill and didn't tighten it down.