X-Axis internal position wrong at boot.
I have started to have a serious problem with my Mini. When I turn on the printer the X-axis head is adjacent to the right hand side stop. If I start a print or perform auto bed leveling the head does not move out far enough for the first 8 measurements. Once it starts the 9/16 in the mesh it reaches the end of the x-axis all the way on the left. The only way to stop this is by moving the head manually to the far left hand side before turning the Mini. The last time I turned it on, not only did it not measure the first 8 points correctly but at 9/16 it ran into the end-stop and the stepper motor started to skip. I have reset the mini but this has not solved the issue.
I believe that when the printer is turned on it has a wrong value for the position of the x-axis.
RE: X-Axis internal position wrong at boot.
The printer does not remember it's position during power off, so all the axis positions are wrong at start up.
But that is not your problem, your problem is the X axis is sticking. You need to clean and lube the rods, checks the bearings are running freely, and that the rods are exactly straight and parallel.
RE: X-Axis internal position wrong at boot.
I will try that. But why does the resistance only happen in one direction? if the rails were not properly lubed up should it not also affect it when it tries to move closer to the vertical pillar?
RE: X-Axis internal position wrong at boot.
I tried to grease the all the rods but it did not solve the issue. I'm not sure it's an issue of sticking. I have attached a video for reference.
RE: X-Axis internal position wrong at boot.
I'm having this same issue, first 24 hours of use, multiple times. I also had the hot end press into the bed once, after having properly (and carefully) completed first layer calibration. Not sure if these issues are related, but it's right after turning on after hours of sitting idle. I also hear the x motor skip when the mesh bed leveling issue occurs.
RE: X-Axis internal position wrong at boot.
I just had the same issue with the hot end pressing into the bed. I was on the live support chat for a couple hours a while back and was told to update to 4.1.0-final. This has not had any effect on the issue, in fact I now get error messages on the screen informing me of the failed mesh bed levelling. I have to factory reset the printer almost every day and redo the self-test to get it to behave properly for a few days. If you set the end GCode to leave the printhead at a position far from the Z-screw side it won't fail mesh bed levelling on start up.
I still don't understand what might be the root cause. I never have x-axis shifts in prints. In fact the prints are fine. The issues with the x-axis were present when I first built the mini as it failed the x-axis self test until I factory reset the machine. Should I have the machine replaced?
I changed it to position 2 where it was previously 178. This is a hackey solution.
G1 X2 Y180 F4200 ; park print head (previous x178)
RE: X-Axis internal position wrong at boot.
@abb
I also had x axis failure in the first self test, but I chalked it up to the Bowden tube getting snagged on the z assembly -- once I resolved that, self test passes (though occasionally fails seemingly due to "cooling down" timing out). Now I wonder if it's related.
FWIW, I never factory reset, and if MBL fails I've found the 2nd or 3rd attempt usually works. I worry about the hotend pressing into the bed again though.
RE: X-Axis internal position wrong at boot.
I think I can consistently reproduce by:
Start self-test hot
Self-test fails during warm up because cooling off takes a long time
Note: z position is reading >200
Run mesh bed leveling -- successful until the very end, it presses into bed. Note: z position is almost 20 throughout.
It concerns me this happens even when I can see the minda sensor working, i.e. the light goes off and the hot end keeps going and parks pressed into the plate.
RE: X-Axis internal position wrong at boot.
It happens whether self test fails or not, otherwise the description above holds... I think actual and perceived z position differing is the issue. Self test ends thinking the z position is 203. Immediately transitioning to mesh bed, the perceived z position is ~17 when minda thinks it's at 0. Then it parks into the plate as described. When I go to settings while parked in the plate, it thinks z position is 185, and the only way out is to auto home which starts out somewhat violently.
Even if there is a hardware issue, the firmware is clearly not gracefully handling whatever is happening.