Not returning “home” on X Axis
I just replaced my hot end on my Mk3S, ran through entire wizard without any problem, after updating the firmware, and started a print. The initial pre print nine point check failed on the far right forward stop, could not locate the proper calibration point. The auto Z correction actually pushed a dent into the steel bed. I didn’t realize at that the time that the extruder has failed to return home to the left of the X Axis. I pushed it home with the power off, ran the print (which i had to stop for a separate reason) and again the head failed to return home.
I googled the problem and see multiple posts with the same issue. I don’t see any advisory or FAQ about in on the Prusa site.
It clearly isn’t the firmware, it’s not the gcode, b/c I had previously printed the same piece from the same .stl from the same settings previously.
i am stumped, plus I now have a damaged steel bed....
RE: Not returning “home” on X Axis
if you move the X axis by hand, does it move smoothly? or does it move with jerks or tight sections?
the Mk3 doesn't have a mechanical endstop, the printer senses increased current when the X carriage bumps into the end of the travel,
If the X axis does not run freely the printer may falsely identify that, as the end of the x axis. this means that when the printer tries to sense position 7, the Pinda is off the edge of the buildplate and fails to sense the actual Z height properly...
reasons for friction on the X axis, include,
Lack of Lubrication,
over tightened Idler wheel bearing bolt,
failing idler bearing,
incorrect orientation of the toothed drive wheel on the motor shaft,
Overtight belt,
overtight back panel on the X carriage
Faulty linear bearing
simplest ones to try are:-
lubricate smooth rails with light oil (not an ideal way to Lube the bearings but it usually gets enough oil in to get things moving)
check the belt is not rubbing anywhere
loosen the screws in the back of the X carriage cover.
loosen the idler bearing bolt a little (it has a Nylock nut, so it doesn't need to be tight!)
regard Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Not returning “home” on X Axis
@joantabb
"loosen the screws in the back of the X carriage cover"
It seems that this may be my issue. After disassembly, I can run rods thru the linear bearings without any resistance. It's not until I reassemble fully that I get binding. It actually seems that somehow the bearings are not lined up perfectly in the carrier. But what's strange is it ran for 6+ months without issue, then suddenly started having this issue.
RE: Not returning “home” on X Axis
@thirdstring
Hi Thirdstring,
This is likely to be a combination of things.
If you did not lubricate the linear bearings, then the shipping lubricant may have helped for a while, then dissipated, leading to increasing friction.
at least you now have a starting point to correct the issue!
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK