I’m a Very new xxl user and the last two days I have been trying to drill holes in my waste board.
But as per lots of other threads my z seems to slip as get 1 hole deep enough then progressively shallower holes. Until they are just scoring the top.
I read through all the threads and have tightened my belt to what I think is guitar string tight. And still slippage. I have stripped and loktited. All my screws. Adjusted my eccentric nuts etc. but it still slips.
Anyways. What I just found now and may help others is the problem lies where my belt is “pinched” around the static toothed roller and then sandwiched between the 2 smooth rollers.
The toothed roller does not have grub screws so it needs the friction of the bolt that holds it to the assembly to stop it rotating. Then the 2 smooth rollers are meant to sandwich the belt teeth together to prevent slippage. On mine there was 1-2mm gap between the belts at the point in between the smooth rollers so the teeth of the belt did not mesh together.
I have done 2 things. Used blue loktite on the static toothed roller to stop it being able to spin then second loosened the the 2 smooth rollers and squeezed them together, and then Retightened the bolts. This has now got the teeth of the belts jammed so slippage should not happen.
Hopefully this can help someone else, it may just need to written more eloquently haha.
Great information! I am having the same problem… and I don’t feel like the z belt tension should be any higher. Speaking as a guitar player I feel that “Guitar string tight” is not really very helpful as in my opinion it has been that tight for a while and yet I keep adjusting higher and it still keeps slipping on very non-aggressive v-carves even where I have progressively reduced the depth of cut and plunge rate to no avail.
I will look at doing what you suggest later today.
Question- every time the z belt slips you can hear it clunk. It must wear out the tooth somewhat. So should the belt be replaced? And is there a benefit to getting a steel or Kevlar z belt?
one thing I had to do was tighten the little m3 “headless screws” that keep the sprocket on the motor connected to the axis of the motor. I had to do this for both the X and Z motors
another thing to make double sure is that nowhere in the path the machine should hit the top or bottom of the Z range; that would “clip” the path afterwards
If we’re thinking of the same thing, that pulley should rotate freely. The only one that shouldn’t is the one on the motor shaft that should only move with the motor.
Sandwiching the teeth together will lock motion.
The belt won’t slip of it’s reasonably tight. The part that typically slips is the pulley on the motor (set screws not tight).
The other thing that you might see that can result in the “clunk” that was mentioned is the stepper motor skipping steps. That’s the result of the motor not being able to provide the force needed to move the belt/Z-axis.
Yup!!! "the “clunk” that was mentioned is the stepper motor skipping steps. That’s the result of the motor not being able to provide the force needed to move the belt/Z-axis."
Glad you got your problem fixed. One more thing to consider when your pockets/holes are getting progressively shallower is the router bit slightly loose. To check this install your router bit as usual. Then take a piece of paper and put it up against the router bit and mark the bit length on the paper using the bottom of the collet as a reference. If you are having inconsistent results with depth check the router bit depth compared to your previously marked piece of paper. If the mark is still in the same place then it is not the bit. Sometimes the bit is not tightened enough and will push up into the collet due to the stresses of cutting. Although the Z axis is usually the problem it is not always and this is just another tool in the toolbox to use.