X axis shift while homing - Odd issue that I can not get answer to
I recently received an assembled Mk3 (I built the Mk2s last year, I had another build project happening so I wanted the assembled Mk3). The unit arrived in okay condition, although the X carriage belt was very loose. This I resolved (atleast I think I did). I spent a week struggling with the first layer z height as the adhesion seemed to change with each test print. After 4 days of some basic test prints, I experienced an odd X axis layer shift (Ie: print shifted to the right, BUT the part completed on the left side, whilst the section on the right was a rats nest. The following day I turned the printer on and attempted to Home the printer which it did, however I pressed Home again and the Head carriage skipped an inch over to the right. I hit Home again and it moved again one inch over to the right. I continued to hit Home until the Head carriage was on the right side of the frame. I did a hard shut down, waited, turned back on and tried to home the printer and it homed on the far right side of the frame. I tried to run the Z calibration and it raised up to top of the frame, came down and almost slammed into the right side frame (turned it off in time). I reflashed the firmware and it made no difference. I checked and adjusted the PINDA height (no change).
What is odd about this is that when I ran the self test, the X carriage check worked fine and ran from side to side as I would expect.
The only clues that I can add are;
1. The X carriage belt arrived very loose and I did tighten it up. It did print for few days.
2. The Z height did not work and seemed to change constantly.
3. I experienced a single slamming against the left side when homing the X carriage.
Sorry for the long dissertation. Has anyone experienced a shifting HOME position ? If so what are the likely causes ?
When I spoke with support they seemed genuinely surprised and did not have a clear cause for the issue.
Any ideas ?
Cheers
Nigel
Re: X axis shift while homing - Odd issue that I can not get answer to
Hello! i have a mk3, and have same problem... when printing,.. in the middle i get a "crash" lcd message, and instead backing home position, move right and keep printing outside hotbed.
and the only way to use back home, correct if is very close this position,... if not... back home, goes to the right....
]
Re: X axis shift while homing - Odd issue that I can not get answer to
Check that the motor pulley is firmly screwed. It seems that thepulley slides on the motor shaft.
Bear MK3 with Bondtech extruder
Re: X axis shift while homing - Odd issue that I can not get answer to
thanks! i`ll double check
Re: X axis shift while homing - Odd issue that I can not get answer to
Also check that the x axis rods are smooth and lubricated. I had this issue with my mk3 where the linear bearings scored the rod and threw off where the motor thought it's end stops were.
Re: X axis shift while homing - Odd issue that I can not get answer to
Hi, I also encountered and still have this issue with a printer received on April 16 in the USA.
I checked the motor carriage tensioner to adjust the belt tension, and the set screw on the timing gear is very tight.
I manually homed the x axis to the left side at start, but during z leveling, the carriage moves to the right and stays extreme right such that the PINDA probe is off the base plate and it will crash the print nozzle. When I try to move the X axis left using the controller interface, it won't move it to the left as it considers the right side to be X=0!
Any thoughts? Seems like an electronics issue.
Thanks, Dave
Re: X axis shift while homing - Odd issue that I can not get answer to
It's probably friction, there are no X and Y endstops, the Controller watches the motor drivers to see increased current consumption and that normally happens when the X axis hits the leeft hand Motor bracket.
a favoutite cause for this is over tightening of the X axis Idler on the right hand X axis end piece. this causes the printer to think it's hit the end of travel and messes up the magic of sensorless endstop working...
try loosening the 3mm bolt, there is a nylock nut on the back so it should not unscrew itself, when the tightness is reduced
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
Re: X axis shift while homing - Odd issue that I can not get answer to
It's probably friction, there are no X and Y endstops, the Controller watches the motor drivers to see increased current consumption and that normally happens when the X axis hits the leeft hand Motor bracket.
a favoutite cause for this is over tightening of the X axis Idler on the right hand X axis end piece. this causes the printer to think it's hit the end of travel and messes up the magic of sensorless endstop working...
try loosening the 3mm bolt, there is a nylock nut on the back so it should not unscrew itself, when the tightness is reduced
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
Re: X axis shift while homing - Odd issue that I can not get answer to
It's probably friction, there are no X and Y endstops, the Controller watches the motor drivers to see increased current consumption and that normally happens when the X axis hits the leeft hand Motor bracket.
a favoutite cause for this is over tightening of the X axis Idler on the right hand X axis end piece. this causes the printer to think it's hit the end of travel and messes up the magic of sensorless endstop working...
try loosening the 3mm bolt, there is a nylock nut on the back so it should not unscrew itself, when the tightness is reduced
regards Joan
sounds interesting, could you show on a picture what bolt and other stuff you mentioned please ?
And btw, thank you Joan for all the help you provide on this forum, this is not the first time I see you are submiting interesting stuff, you deserve to be thank, at least 🙂
Re: X axis shift while homing - Odd issue that I can not get answer to
Hi Jean Marc,
thank you for your kind wards,
I have identified the 3mm bolt on the attached picture for you, I hope this makes sense
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
Re: X axis shift while homing - Odd issue that I can not get answer to
I felt it necessary to respond to my own post. This was a pre-assembled printer, not assembled. Note: it actually goes through the self test without issue and detects left and right side of Z carriage. X rods smooth, no issues with movement. No friction whatsoever. This obviously has something to do with the Tri-drivers. If there were a physical defect it would affect the self test also.
It was interesting enough of a problem that Prusa support wanted me to return the printer (Im honored 😀 ).
I ordered a kit instead, atleast then I cant blame me not UPS 😆
RE: X axis shift while homing - Odd issue that I can not get answer to
I'm having the exact same problem. Not at home to try loosening the bolt Joan mentioned. Did that solve the issue for anyone in this thread?