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Z axis Not Going UP and Down Properly

I have had an issue with the z axis since I set my new machine up 3 weeks ago. It will go up and down but sometimes will skip a revolution and then just go down 2 revolutions’ all at one time. It seems to do this mostly going down. It happens pretty much every time I set the machine up to start a cut. I did what another user suggested and measure the distance up and down and told it to move one inch. It went up fine from 10 inches to 11 inches …but when I told it to go down from 11 to 10 it only went to 10.3 and stopped. I then did another down command and it went all the way to 9. I had a project that I was working on and it cut the first square fine but then the z axis did not go high enough to move over to the right and start the next cut. It dragged on the wood a little bit …it was probably about 1 mm to low.

I have gone through and tighten all the belts and wheels and made sure there were no loose wires and my material is clamped down very well.

I put another test piece in right now and it’s not dragging the bit anymore. I am not sure if this was just a one off glitch or if I need to do something further.

Any insight would be helpful.

What model cnc?

And if this is the standard xcarve, is it the new z axis (with linear rails) or the old one (with v wheels and a circle belt)?

it’s the new x-carve. I just received it after Thanksgiving 2021

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Sorry, I should have specified in my prior question, not a Xcarve Pro, right?

Regarding the calibration, for the measuring and comparing send command vs actual result, the more distance move, the more accurate the calibration will be, so moving the entire 10" would be best forthe calibration part.

To prevent the machine from moving on its own while at idle you can set it to make the steppers lock in position and hold firmly during idle times by setting $1 to 255 this can be done within machine inspector (Ctrl+Shift+D) and then typing $1=255 into the console part at the top left… (check the current value first by scrolling to the bottom and seeing what the current value is, then after sending click the little refresh button down there and verify its updated)

The issue could also be caused by backlash… there is a black nylon antibacklash block that may need adjusting, this only effects the Z since it uses a lead screw design.
The hardware is a little different on the xcarve, but the silver screw shown on the right here is the adjustment for backlash, you can check for this being the issue by having the machine on and with $1=255 set, then try to lift and lower the Z by hand, can you lift it up (is there vertical play) if yes, then likely the backlash nut isn’t tensioned right and the screw would need to be adjusted…

Hi Seth,

I read your notes over the holiday and we went and look through the z axis and the instructions online to make sure we did not miss anything. We did notice we are missing 2 screws for our z axis. Do you think these 2 screws are important to the Z axis ? I emailed customer service but have not heard back yet.

Thank you for your insight !

I’m not 100% positive only maybe 95% but i believe those screws hold that plate to the nut block from my prior photo, unless they used some other method to attach it…

I have a different model cnc, very similar to the xcarve with regard to the z axis… mine has those screws… :man_shrugging:. Without them then my plate would just float freely with no hard connection to the lead screw