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X Axis not moving at initial testing  

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Jesper
(@jesper-2)
Active Member
X Axis not moving at initial testing
I have just assembled my MK3S printer and started the calibration process. However, when the calibration of the x-axis starts, the x-axis just slightly skips from one side to the other (about 0,5 cm) and the stops and gives “prusa x-axis length error”. I have tried to move it manually in the settings menu, but it keeps skipping just a little from one side to the other even though I am turning the knob the same way. I feared that it was the stepper motor that was faulty, but when I tried to swap the y-axis to the x-axis connector on the main board, it did the same with the y-axis when manually trying to move it in the settings menu. Do you have any idea what could cause this? Both Y and Z moves freely when
operated in the settings menu
 
 
Please see you tube link where my problem is shown
Thank you for any help 
 
Posted : 13/04/2021 10:26 am
Jesper
(@jesper-2)
Active Member
Topic starter answered:
RE: X Axis not moving at initial testing

https://forum.prusa3d.com/wp-content/uploads/2021/04/20210412_224346.mp4

Posted : 13/04/2021 10:36 am
Dan Rogers
(@dan-rogers)
Noble Member
RE: X Axis not moving at initial testing

Turn it off.  Gently move the X axis by hand.  It should resist the motor (or better yet, disconnect the belt for this) - you are looking for binding.  Your motor is telling you it cannot move the head successfully.  It is counting revolutions between left stop and right stop, and is experiencing pressure too hard for the motor to move.

Probably the X axis assembly is not seated properly (rods are not pushed all the way home) - that would make the two rods non-parallel, and possibly slightly twisted.  That puts a lot of pressure on the bearings - so it can't move smoothly.

Then, once you confirm that it is binding, you'll need to take the X axis assembly off (remove the extruder but let it sit on the bed (with something soft under it), remove Z top and bottom, remove extruder)Then look in the inspection holes at the ends of both orange parts - you are looking into the very far end of each hole.  you should not see a space  you should see a shiny metal rod pushed all the way home.  Check all four.  Push them in where not seated.  Reassemble.

 

Posted : 13/04/2021 1:23 pm
Jesper
(@jesper-2)
Active Member
Topic starter answered:
RE: X Axis not moving at initial testing

@dan-rogers

Thank you. I will see if that helps. To the best of my knowledge/abillities, the rods should be firmly seated, but I will give it a go.

Posted : 13/04/2021 1:26 pm
Dan Rogers
(@dan-rogers)
Noble Member
RE: X Axis not moving at initial testing

It might be something else binding - but binding it is.

 

Posted : 13/04/2021 1:27 pm
Dan Rogers
(@dan-rogers)
Noble Member
RE: X Axis not moving at initial testing

A totally random thought - if the screws are not in the pulley on X motor, it might look exactly the same.

Posted : 13/04/2021 1:28 pm
Jesper
(@jesper-2)
Active Member
Topic starter answered:
RE: X Axis not moving at initial testing

@dan-rogers

Scews in the pulley are firm. When the printer is off, the extruder moves with some force, but I guess that´s the stepper motor giving a little resistance

Posted : 13/04/2021 1:32 pm
Clarmrrsn
(@clarmrrsn)
Honorable Member
RE: X Axis not moving at initial testing

@jesper-2

I would suggest to check your motor pulleys as well, looks like something is stopping it from moving at all.

Make sure the Motor side pulley has clearance between it and the motor if its rubbing could be causing a lot of resistance and triggering sensorless homing (looks like it has but hard to see) check the belt is not rubbing against the rod holders and has clearance to move freely tbrough the gaps in the rod holders.

Check the idler pulley as well  make sure the screw is not over tightened, if the screw is too tight the pulley cant spin.

Tank you very much!

Posted : 13/04/2021 1:42 pm
Jesper
(@jesper-2)
Active Member
Topic starter answered:
RE: X Axis not moving at initial testing

@clarmrrsn

Thanks a lot. I will give your suggestions a go. I actually didn´t think you could over tighten the idle pulley on the right, but it might be too tight.

Posted : 13/04/2021 1:44 pm
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