Z axis skipping when going up, not down

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This topic contains 4 replies, has 4 voices, and was last updated by  Ryan 6 months ago.

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    I’m building my first CNC using the kit from V1 engineering (ramps 1.4, 30a power supply). At the moment, I’m using the LCD from V1 as my controller. I got everything wired up for the first test run, and the X and Y axis are moving great! The Z is… slightly less great.


    When I  move my Z axis (using the “Move axis” commands from the LCD panel), I’m seeing the down movement work nice and smooth, but when going up it seems to catch on every full rotation of the stepper and pause for a second before continuing. The stepper itself is running fine, it the threaded rod that is stopping briefly before starting again.


    I realize it’s a bit of an odd situation, so I figured a video would help: https://drive.google.com/a/hilstrom.net/file/d/1Ra2yM2IXb_43ezdvACjsaJ1P76PeE_kA/view?usp=drivesdk


    It seems like a common problem is the threaded rod binding in the mount. Mine turns very easily by hand (if I drop it while in the mount, it will spin down and fall all by itself), so it’s probably not that.


    At this point I figured there wasn’t any harm in checking to see if others had this problem before I started taking things apart and possibly making them worse than they are. If anyone has ideas, I’d appreciate them!



    Make sure that everything is correctly assembled according to the instructions, and grease the threaded rod.

    On my first cnc build I had a similar problem and liberaly greasing the threaded rod helped a lot.



    Check the coupler set screws and make sure they are tight to the threaded rod.  If they slip a little, it could cause your issues.



    Is your Z axis moving down by the right amount? As in are the Z axis steps per mm correct?

    I agree with everyone above as well, all common Z issues.



    Actually, you can see it your coupler is loose. The stepper never stops turning but the screw does.

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