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Z Axis not moving during print

WhiteRenardWhiteRenard
in Questions & Answers
Hey,

I'm new to 3D printing and I've recently finished building my printer (Cherry 3D printer) and have been trying to fix it's problems, this one I could not figure out, so maybe you guys can help me out! :D


The problem is the Z axis does not move up after the printing starts. It DOES however move during homing and in manual control. This results in the everything getting printed on first layer...


I am using firmware 0.92 btw. And the driver currents are adjusted correctly. (0.12 mA, they are small steppers!)
The endstops are working correctly, they show low when endstops are not triggered and high when they are.

Z-axis Max Feedrate:       0.3 mm/s
Z-axis acceleration           5 mm/s^2
Z-axis travel acceleration  5 mm/s^2


Also, if and whenever I press "Emergency Stop" button to stop everything and then try to move the Z axis, it won't move. I'll have to wait a few seconds for the non-existent Z movement (as if it's actually moving when it's not) to be finished and then the next Z movement commands work.

Comments

  • RepetierRepetier
    Normally I'd say acceleration/speed to high but your values are already low. I assume in eeprom you see the same values?

    You should try disabling ALWAYS_CHECK_ENDSTOPS just to be sure it is no endstop issue. But in that case you would not have to wait for z move to finish as described.

    What happens when you do 0.1mm steps in host manually. Just to simulate the layer switch moves.

    Also could be the power unit to small? Does z still work with extruder on and bed on? Does it vibrate when it should move but does not, or give a high pitched sound. Both indicates loosing steps from lack of force.
  • WhiteRenardWhiteRenard
    edited April 2016
    Normally I'd say acceleration/speed to high but your values are already low. I assume in eeprom you see the same values?

    You should try disabling ALWAYS_CHECK_ENDSTOPS just to be sure it is no endstop issue. But in that case you would not have to wait for z move to finish as described.

    What happens when you do 0.1mm steps in host manually. Just to simulate the layer switch moves.

    Also could be the power unit to small? Does z still work with extruder on and bed on? Does it vibrate when it should move but does not, or give a high pitched sound. Both indicates loosing steps from lack of force.
    Thanks for responding to my question! :)

    Yes, I set those values using EEPROM, it's correct.
    I've tried triggering the Z endstop manually before it reaches Zero location so that it would print in mid air, then if endstops were inverted or something, it would move towards the bed. But still no movement.

    0.1 manual movement works normally, even 0.01 works as well. I tried 10 as well, works fine. 

    I tried manually heating the hotend and all the axis work here as well.
    My power unit is rated for 30A, and my printer is using small steppers that only take 0.1-0.12 mA, and no heated bed.

    The fans are too loud for me to hear the motors well, but before I had the fans set up, I did hear the motors make noises. They don't seem to lose steps though as every requested movement is consistent. I had the current wrong when I was setting my printer up and I heard the high pitched noise, it's kind of different from the ones they make now.
  • RepetierRepetier
    Very strange. z moves during print are identical with the one you do manually, so there is no reason why it should not work then when it works during testing. 

    So what this normally means is that during printing your conditions are different causing the problem. Main difference is bed/extruder heating which you already excluded. Not sure what else is different. You could write a small gcode with z moves and some xy moves in between for testing. That should work. Then add more and more of the print  gcode making problems in the beginning until the problem reapears, then you know which commands cause the problem which should help finding the reason.

    BTW: Can't believe your motors use only 0.1ma. Mine are using 1700 - 2200, so I gess you meant 100mA which is still not much. I'm wondering that the force is enough to drive everything.
  • WhiteRenardWhiteRenard
    edited April 2016
    Very strange. z moves during print are identical with the one you do manually, so there is no reason why it should not work then when it works during testing. 

    So what this normally means is that during printing your conditions are different causing the problem. Main difference is bed/extruder heating which you already excluded. Not sure what else is different. You could write a small gcode with z moves and some xy moves in between for testing. That should work. Then add more and more of the print  gcode making problems in the beginning until the problem reapears, then you know which commands cause the problem which should help finding the reason.

    BTW: Can't believe your motors use only 0.1ma. Mine are using 1700 - 2200, so I gess you meant 100mA which is still not much. I'm wondering that the force is enough to drive everything.
    Yes, you're right, I meant to say 0.1A or 100mA, my bad! 

    I also posted this issue on reprap forums and just now I took a suggestion to change acceleration to 0.1 and Z jerk to 0 and also increased the current of Z mtoros (about 50% more).
    Now I'm printing!! 

    Not sure which of those changes did it, but I'm gonna try the old settings after this print to see if it was the current or the settings, or perhaps both!

    Thanks for your help, much appreciated! 
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