Intermittent X axis problem during bed leveling
This problem comes and goes and I'm looking for some tips on how to debug it. I recently upgraded to 3.0.10 firmware and didn't have the problem previously (although that may not be related). During the bed leveling process, when moving to the third point the X axis will get jammed and stutter, causing the calibration to fail. It appears to be a mechanical issue however if I turn the system off and on, sometimes it will not do this. If I leave the system on and just repeat the bed leveling process it will do the same thing every time (even after reset the electronics with the X button). It seems like I have to completely power off and back on again to make it work. If it passes the leveling process, I can print everything normally so I doubt it is a real mechanical problem.
I've also moved the print head by hand and it does not feel like there is any more force to move it on the right than there is on the left. I placed a brief video here:
Can anyone offer some advice on how to troubleshoot this?
Re: Intermittent X axis problem during bed leveling
Here are some tips trying to diagnose issues with the x-axis:
1) turn off the printer and see if you can move the head smoothly by hand. You want smooth movement all across with no binding anywhere
if it ain't smooth, unhook the belt and try again..
2) check the grub screws in the motor pulley. They need to be tight and one of the 2 screws needs to be tightened against the flat side of the motor shaft.
3) check the 2 screws on the side of the X-axis (see http://manual.prusa3d.com/Guide/4.+Z-axis+assembly/106#s1610 ) if they're too tight, it could cause issues.
4) check the belts - unfortunately, this is not terrible precise thing: too tight or too lose could be a problem - also belt ends sticking out of the belt holder could start rubbing on the belt below it and cause resistance - maybe shorten the belt ends a bit if that is the case.
(if you're using silent mode, it's even more important to get the axis moving smoothly. High power mode while louder is less prone to skipping steps, as the motors get more current and there have more torque)
Re: Intermittent X axis problem during bed leveling
Thanks, I think #3 was the issue. These screws must have been too tight. It's a little tricky to figure out how tight they should be. We loosened them a little and things have been OK so far.
Re: Intermittent X axis problem during bed leveling
A good recommendation for these screws is using a multimeter in continuity test mode - if you happen to have one: Tighten the screws just enough so you get continuity, no further.
Josef Prusa mentioned somewhere some time ago these screws arent even necessary anymore - but i can't finde the original source to quote properly..