Printer loosing home point?
I just built a mk3 and I have the latest firmware.
I do initial calibration and everything is fine. I do a test print of a large cube to set the live Z during the first layer. Get it looking nice and then stop/cancel that print so I can try print something I actually want. I cancel the print by pressing the knob and scrolling down to stop print. So far everything works as it should.
Go and start the new print and the nozzle doesnt go to the 'home' position on the X axis. So when it does the 9 point calibration the first point is ok (it is somewhere along the front edge of the print bed but not necessary to the left). When it does the second or third point, the pinder probe over hangs the print bed and when it goes down the nozzle digs into the print bed. Then I get an error about levelling failing and check if nozzle is dirty. Its like it forgets where the home point along the X axis is to start the first of 9 point in the correct position.
Ive tried turning the printer on/off and starting a new print and doesnt work - same issue where the 9 points are right of print bed so when it gets to the second or third point the probe isnt over the print bed and the nozzle sinks into the print bed.. When I go to auto home it is somewhere at front right of the print bed!! When I go to move axis the 0 point is towards the right...
The only way to 'reset' it is to do the self check again. Once that is done I can print and it works fine.
Whats going on? I dont think the belt is jumping a tooth or anything - doesnt sound like it. The grub screw on x axis motor is tight. I loosened the screws at the back of the x axis bearings slightly. Nothing has helped.
I now have a bunch of dents in my print bed now on the front right corner 😡
Re: Printer loosing home point?
edit:
Did an entire print of the prusa logo and then when I do it the second time it works fine. The printer homes the nozzle after the print. It seems there is only a problem after i cancel the print...
Re: Printer loosing home point?
The exact same thing is happening to me! Finished assembling the printer today, test prints went fine, but when I stop a print through the menu or the printer cancels a print on it's own, the home position is lost. I have dents in the front right corner, just like you, from where the printer dug the extruder head into my steel print sheet, and gouges in my heating bed from when I thought maybe it was doing a test that required me to not have the sheet on the bed. Did factory resets, flashed firmware to lastest version, lossened screws on the back of the x-axis extruder plate. Nothing has worked.
I'm getting the exact same errors. This is the MK3S model.
Any resolutions? The whole point that I bought a Prusa was for the fail safes, and those are NOT working.
Re: Printer loosing home point?
@Max -- Did you perform the manual step of setting the PINDA height before you ran the Wizard calibration? If the PINDA isn't set correctly, especially too high, the nozzle will do exactly as you've described.
See Step 3.
https://manual.prusa3d.com/Guide/9.+Preflight+check/1053?lang=en
@Ronald -- After a print, the extruder is moved up and to the right, away from the print; it isn't "homed" ... Home is the lower left front of the bed.
Re: Printer loosing home point?
I am running into this as well .
I assembled the printer a week and a half ago and have been using it everyday , Yesterday I installed a set if Igus bushings to the axis slides rods and when I went to recalibrate it I had some troubles and had to start over several times , I finally got it set up and it checked out ok , as soon as I went to print I noticed it did not go home first it stayed in the middle of the work plate up front and tried the leveling , of course it went all the way to the right and stalled out and said there was a Z level failure ??
I can go through the whole process again and it will check out but as soon as a print is started it will fail ..
I am thinking that somehow it remembers where the extruder head was in relation to the E steps on the axis motor and when I removed the belt to install the bushings it keeps trying to revert to this position ??
Re: Printer loosing home point?
The position logic is pretty simple. Power off and back on the printer has no clue where it is and must find home. It does this by moving the bed fully back until the motor stalls, and the extruder to the left until the motor stalls. Then it moves the Z-Axis down until the PINDA switches off. That point is 0,0,0 in the coordinate system. If at any time during a print the extruder is bumped, the bed bumped, or the motors stall, the printer is lost.
This is why the printer "homes" before every print. It needs to know where to start, just in case you moved something manually; which is very easy to do removing a part, cleaning the bed, etc.
Re: Printer loosing home point?
As I understand it, if you have an axis that is bound up, the printer thinks it's hit the hard stop and stalled when it might actually be out in the middle of the print bed. So watch out for a binding axis if your printer can't find home correctly.
Re: Printer loosing home point?
I understand what your saying ..
Whats actually happening with mine is when the printer stops by aborting the print the extruder runs up a few millimeter then over to the left a few millimeters , if you don't actually move the extruder manually over to the left it will start the leveling process from the point it stopped at , In other words its not finding home first like it should .
My mk3 still does this every print but my mk2s does not , Im wondering if its a change in the firmware that it might need ?
Re: Printer loosing home point?
Check your startup gcode, it might be missing the initial G28 W ...
Re: Printer loosing home point?
would love to see an answer on this. I am on my 3rd day of printing with this and im running into this issue as well
Re: Printer loosing home point?
would love to see an answer on this. I am on my 3rd day of printing with this and im running into this issue as well
Zip a gcode that has this issue and post it here.
Re: Printer loosing home point?
I was struggling with this right after it was assembled. I double checked everything and found my y-axis belt was slightly loose. As the build plate went from back to front, there was a slight skip.
I just tightened the belt and my problem is currently fixed! Hopefully that was the problem.
Re: Printer loosing home point?
Interesting to see other people are having a similar issue to me. I was in the middle of a print just a couple days ago and everything was working fine when suddenly, mid print, the printer loses all calibration and is entirely lost. Now no matter what I do, it cannot auto home or calibrate and I'm not sure what I possibly can do at this point.
Re: Printer loosing home point?
It happens.... I have been printing fine until the most recent update and had similar issues after flashing the latest firmware without prior issues. I shut down and restarted and it went away after...
Turn off your printer and restart helps clear weird stuff. Also, a reinstall of the firmware and restart can help with strange problems like that. I think, but have no proof, that the software sometimes glitches and after an install for firmware or a weird isolated issue like that a shutdown and restart fixes a lot of the issues, possibly related to stuff in the memory.
If it is a continuing issue, submission of a github issue with pictures and good detailed information will help the developers institute a fix.
You are not alone, a lot of posts similar in nature have been posted recently.... I wonder if something in the latest firmware is causing this as there have been many reports recently.
Strange women, laying in ponds, distributing swords, is hardly a basis for a system of governance!