New build, Y axis issues
I'm hoping some of the more experienced folks can help me out. I have a new Mk3 kit, built up this weekend and am running calibration and test prints. I have noticed some things that concern me.
1. Y & X axis movement - with the belt off the motor, movement is smooth. With the belt connected to the motor if I move by hand the movement is in pulses. With the power off, each pulse makes the LCD light up. Is this normal?
2. something seems to be up with the homing. After a test like first layer calibration, if I clean the bed and start printing then the Y carriage doesn't move to the back of the printer and the first row of Z calibration points are along the back of the print bed not the front. If I move the Y carriage to the back of the printer by hand, Z calibration works and a print can start. If I Autohome, then the positions the axes end up in seem random.
I have played around with belt tension and have got the U bolts about as loose as I dare. I honestly think the biggest issue is this pulsing resistance coming from the motors.
Any ideas?
Also, where on the controls are Y and X axis jog mode? I hold the knob down and get Z axis jog, but I can't figure out or see any guide to jog mode on the other axes. I'm not supposed to just push them manually into position am I?
RE: New build, Y axis issues
Welp, now neither X or Y will move at all by hand. Will still move if commanded to by the controller, but with hand movements they are rock solid until pushed hard enough that the belt skips teeth - this is following a crash during the first layer calibration caused by the printer doing the 6th Z axis calibration point, detecting a crash (though no physical crash seen) then restarting the routine with point number 1 in the same position as the previous run point number 6, which obviously caused it problems when it started trying to run the Y axis off the rails.
and it's back to a Y axis length self test error.
RE: New build, Y axis issues
Got rid of the Y axis "pulsing". Weirdly the root cause seems to have been that the grub screws holding the toothed pulley on the Y axis motor were too tight. Of all things.
I was testing removing the motor from the equation, undid the grubs, noticed that the motion was smooth and that the shaft in the motor was still turning with the manual motion. Tightened the grub - instant pulsing.
So how would this be? are these little grub screws such a significant cause of tension on the Y axis?
RE: New build, Y axis issues
1. Yes it is normal. The motors are step motors. Move the carriage slowly.
2. Haven't seen this behaviour before. I would power off the whole thing and start a new Calibration Wizard. And stop moving the carriages too fast.
3. Belt tension is mentioned in the manual. You can find a menu item that can tell you what the tension is.
The U bolts are specifically mentioned as "turn both the nuts until they touch. Then turn the nut 90 degrees further. No more. No less."
No jog mode for x and y. Move by hand. Slowly. Moving the z should be all you need to do. The rest is done through GCODE.
RE: New build, Y axis issues
I had problems with my Y axis too, the tension in the Calibration menu read 210, it initially worked but caused later problems as was too tight and the motor had problems moving the bed properly and it stopped altogether and on running self test again got the failed Y axis length, slackening it off gives a higher number and it resolved my problem.