Engraving small font - the bit digs deeper and deeper as the job goes on. 6040z

[lucan07]

Another possibility on the 6040z (especially with the standard electronics) is missed steps that occur on upward Z travel. Not sure if that can be ruled out in this case as I haven't watched the video, but could apply in other cases.

Good point I seriously doubt this slipping coupling is the problem its two pieces held together by the friction of the rubber alone so if ends stay firm nothing to stop rubber moving.

[lucan07]

In fact that's the only thing that makes sense if everything else is secure the rubbing coupling is causing enough friction for the stepper to miss steps so that the Z axis is losing its integrity.

[magicniner]

What you talkin' 'bout Willis?

[cropwell]

Some thing is pulling that coupling apart. If it were just loose on the stepper shaft there is no force to pull it downwards. I would recommend running the program but just cutting air and looking at the Z axis to see what exactly is moving.