Factory Core One Y-axis and homing failure after ~60 successful prints
After successfully printing a job last night, I turned on my Core One this morning and out of nowhere it just will not pass the homing or Y-axis tests.
I have done all the recommended fixes:
- Belt tension is spot on the correct values(98/92).
- The gantry is perfectly flush with the stops(both front and rear) on both sides. I cannot even see light through the gaps while squeezing the opposite side.
- I have inspected all the belts, pulleys and gears, and everything it seated correctly, clear of debris and otherwise normal.
Whenever the printer does the Y-axis test or homing test(which is for everything...), it correctly probes both the X- and Y-axis stops in the front right corner with a clear banging sound, but then proceeds to do the fine calibration in an area between 5mm and 15mm from either stop over and over until the printer reboots with the red error screen. Isn't it meant to probe for the stops during that part? I could have sworn that before today it would just jerk back and forth a few times, clanging on the both stops and then it was done. Now it almost looks like it is probing for the stops in an area WAY to far from either stop and just gives up when it cannot find them.
In case the printer had saved a bad "expected area" to start probing for the stops, I did a factory reset and tried to run though all the calibrations again. But same issue. Every test passed except the Y-axis calibration, because homing fails.
I did have an extruder crash several days ago, when the extruder bumped a piece of support. The printer didn't detect it and just started printing slightly offset in Y, but I heard it and aborted the print when I saw what happened. But it has printed nearly a dozen successful prints(and homed correctly many more times) since that with no issues.
What the heck happened? How do I fix this?
RE: Factory Core One Y-axis and homing failure after ~60 successful prints
Completely loosen the belt tension and check if the gantry is still square. Also, move the gantry by hand several times and check if the movement is smooth and doesn't bind anywhere. Then turn the belt tension screws evenly. Start with 1 turn of each screw alternating between them until the belts tighten and you are within range of the belt tuner. Then switch to 1/8 of a turn, alternating between screws. Check that the gantry is still square when completed.
Before you do anything drastic first run through: https://help.prusa3d.com/article/regular-printer-maintenance-core-one_829710
- in case something simple is triggering the problem.
Cheerio,
RE: Factory Core One Y-axis and homing failure after ~60 successful prints
Before you do anything drastic first run through: https://help.prusa3d.com/article/regular-printer-maintenance-core-one_829710
- in case something simple is triggering the problem.
Cheerio,
Yeah, I tried all that. Even re-greased the rails. No change. It still tries to home way too far from the stops.
RE: Factory Core One Y-axis and homing failure after ~60 successful prints
Completely loosen the belt tension and check if the gantry is still square. Also, move the gantry by hand several times and check if the movement is smooth and doesn't bind anywhere. Then turn the belt tension screws evenly. Start with 1 turn of each screw alternating between them until the belts tighten and you are within range of the belt tuner. Then switch to 1/8 of a turn, alternating between screws. Check that the gantry is still square when completed.
Tried that and the gantry was within maybe half a millimetre off with the belts loose. Oddly enough it was off oppositely when I tried the front and rear stops(tolerance on the frame?). Everything also ran smoothly.
I gently nudged it so it was perfect with the front stops, re-tensioned both sides equally and it was still straight(within a hairs width). But it changed nothing. It still tries to home more than 5mm from the stops and times out when it never finds them...
RE:
Here is a video of it trying to home:
This is a snippet of where it actually gets closest to the stops(roughly 4-5mm). Other times it tries much further away(12-15mm). As you can see, and hear, it does correctly probe for both stops. But then it drives ~10mm away from them in both directions and start probing for them by moving back and forth 5mm...
It kinda reminds me of an older printer I worked with that had a random bit-flip(or some other corruption) of a position, and would just not stop trying to find that position in a completely wrong location...
RE:
Here is a full video of the failing homing procedure:
As you can see, it never comes close to either stop...
RE: Factory Core One Y-axis and homing failure after ~60 successful prints
Completely loosen the belt tension and check if the gantry is still square. Also, move the gantry by hand several times and check if the movement is smooth and doesn't bind anywhere. Then turn the belt tension screws evenly. Start with 1 turn of each screw alternating between them until the belts tighten and you are within range of the belt tuner. Then switch to 1/8 of a turn, alternating between screws. Check that the gantry is still square when completed.
Tried that and the gantry was within maybe half a millimetre off with the belts loose. Oddly enough it was off oppositely when I tried the front and rear stops(tolerance on the frame?). Everything also ran smoothly.
I gently nudged it so it was perfect with the front stops, re-tensioned both sides equally and it was still straight(within a hairs width). But it changed nothing. It still tries to home more than 5mm from the stops and times out when it never finds them...
Can only guess then at the point. Maybe the XY frame and/or rods are misaligned? At this point the best recourse is to get online with support.
RE: Factory Core One Y-axis and homing failure after ~60 successful prints
I suppose one last thing. Are the pulleys for the X and Y motors installed correctly? Perhaps look through the hexagon holes for the motor housing and confirm.
RE:
Completely loosen the belt tension and check if the gantry is still square. Also, move the gantry by hand several times and check if the movement is smooth and doesn't bind anywhere. Then turn the belt tension screws evenly. Start with 1 turn of each screw alternating between them until the belts tighten and you are within range of the belt tuner. Then switch to 1/8 of a turn, alternating between screws. Check that the gantry is still square when completed.
Tried that and the gantry was within maybe half a millimetre off with the belts loose. Oddly enough it was off oppositely when I tried the front and rear stops(tolerance on the frame?). Everything also ran smoothly.
I gently nudged it so it was perfect with the front stops, re-tensioned both sides equally and it was still straight(within a hairs width). But it changed nothing. It still tries to home more than 5mm from the stops and times out when it never finds them...
Can only guess then at the point. Maybe the XY frame and/or rods are misaligned? At this point the best recourse is to get online with support.
Everything looks fine. Nothing is bent or loose. Everything runs smooth when I move the extruder head or pull on the belts by hand.
Yeah, I have already contacted them for support. Thought I would try here first, but it takes 4+ hours for my posts to get approved by moderation, so it is slow going :/
I suppose one last thing. Are the pulleys for the X and Y motors installed correctly? Perhaps look through the hexagon holes for the motor housing and confirm.
Yeah, one of the first things I looked for. Saw the issue cropped up a lot with kit builds. They are both orientated correctly(opposite of each other), belt is correctly seated on them and the set screws on the pulleys are tight.
Also, it really does not seem like a matter of the homing failing because inconsistencies in measuring the stops, as would be caused by loose belts, offset gantry, slipping pulley etc. It does not even touch the stops when trying to do the Precise Homing step. It performs all of it too far from the stops to ever find them. I honestly looks like a software error to me. Like a corrupt or incorrect starting value for initiating the search for the stops. But I cannot understand why that would persist through both factory reset AND re-flashing the firmware. And it clearly probes for both stops, then just moves away from them to start the Precise Homing procedure. but that would be horribly programmed if that were the case...
I posted two videos showing this bizarre homing process already, but both are still awaiting moderation...