Hi all, I have a quick question about my z screw coupler (as i understand it, the metal cylinder at the bottom you can manually move your z axis up and down with).

When I manually raise the z axis (with steppers disabled) by rotating the coupler clockwise, after I let it go, it reverses it’s rotation on it’s own and sinks back down. This is frustrating because it takes forever to actually move it any distance. Am i doing anything wrong? Should you only ever move the z axis with software, and if so, is there a way to fix the issue of it going back down? I don’t know how to adjust the tightness of this part, I’m still pretty new.

  • dual_sport_dork@lemmy.worldEnglish
    2·
    6 months ago

    I suspect the weight of your build platform is sufficient enough to turn the Z axis leadscrew against gravity and overcome the friction within it and the motor. I’ve never seen a printer do that myself, so I don’t know if that’s indicative of any kind of failure on your particular model. When the stepper motor is energized it holds itself in position which is why this doesn’t happen, for example, during a print.

    If I were you I would just move the bed via software or your printer’s control panel if it presents the option. That should be safer, faster, and not slowly give you carpal tunnel as an added bonus. I haven’t done the math via figuring out the screw thread pitch and so forth, but for example my X-Max 3 has a total Z axis travel of something like 330mm, so it would take an entire month of Sundays and hundreds of manual revolutions to screw the damn thing from bottom to top by hand. I have a machine precisely for doing that for me…

    • ArtVandelay@lemmy.worldOPEnglish
      1·
      6 months ago

      Thanks, that’s probably the route I will take. Just wanted to know if that behavior was abnormal or not, but it sounds like it’s not too far outside the realm of people’s experiences in general

      • dual_sport_dork@lemmy.worldEnglish
        1·
        6 months ago

        Probably.

        FWIW with the motors unlocked I can just push on my print bed either up or down, and it’ll move. Mine just doesn’t move under its on weight. Maybe it would if it had a big model on it or something, I dunno.

        If yours is a bed-slinger gantry machine where the head moves up and down rather than the print bed, the same applies. Just in reverse.

  • rambos@lemm.eeEnglish
    1·
    6 months ago

    If you have only one Z screw you are fine. But if you have 2 Z rods with stepper motor on each one, they can get out of sync when losing power. You can print Z motor brake to solve that problem

  • asbestos@lemmy.worldEnglish
    1·
    6 months ago

    It happens, and has happened to me while moving it manually, especially if I stop and let go abruptly. If I do it gently, it’ll stay in place. It also happened a few times when I didn’t screw the Z coupler properly so it just spun out. The weight of the print head along with the general resistance and stepper rotor magnetic resistance should be enough to make it stay still, and I assume it stays still as well when you turn off the printer. Or does it just crash onto the build plate?

    • ArtVandelay@lemmy.worldOPEnglish
      2·
      6 months ago

      I don’t recall it ever crashing, with the printer on or off. I can test explicitly what it does when the printer is off, when my current print finishes