Loosing Zero or slipping?

I’m losing zero on my z axis half way through cut. My letters are off and it doesn’t contour cut all the way through any more. Everything is tightened down, could it be too tight? Video for help.

Hi @Shawnamarks3,

Assuming you have the stock belt-driven Z axis, this is likely a problem with the pulley slipping on the motor shaft, due to loose set screws.

You should go and inspect the pulley on the Z motor, make sure one of the set screws is aligned with the motor shaft’s flat, and that both screws are present and tight:


The other possible reason is using too aggressive plunge rate / feeds and speeds, which can lead to losing steps on the Z axis

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It’s a normal toolpath that had been ran prior to this messing up a week ago and was fine then. My husband took apart the whole z plate deal to tighten everything. Ran a sign and the only letter that messed up was 0. Then ran a contour run of the shape of TX (same file that had been ran multiple of times fine) half way through it was cutting air and it was off on a diagonal type of pattern (top left and bottom left were off) now it’s almost like its going backward halfway through the cut and cuts air now. Starts off fine and normal on the cut.

We recently had a problem of it not homing and error of finding the homing switch. Powered everything down and now z is stuck and will make the movement sound. No movement

It is possible that the set screws were fine last week and got loose, so I really recommend you go and inspect whether the Z motor pulley is slipping on the motor shaft. An easy way to do this is draw a line with a marker across the pulley and shaft, like so:


Then jog the Z axis or run run job, and when it starts cutting air, check whether the line is still straight.

It’s normal that the job would be fine when starting, as you probably re-initialized the machine/the zero point right before starting. But the slippage happens after that, leaving the machine cutting air.

Your last statement makes me think that the set screws got completely loose and now the Z axis shaft is turning in the air.

If you still struggle with this, you can and should contact support@carbide3d.com


Is the motor moving inside the pulley?

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