Selftest Y Axis Length Failing
I apologize if this has already been answered., but I've looked at some of the other posts around the Y-Axis length failing and don't think they're quite my problem.
First, my MK3 was assembled at the factory, not a kit. Upon arrival my son quickly set it up and was able to print at least 4 different designs from the included SD card. However, when he went to print the castle, things went haywire. About 2 hours into the print the print bed wouldn't move and began making a grinding noise. I then entered "debugging" mode.
First, I used the "Move Axis" functionality to move the bed all the way back. The readout went to -4, which I found to be a trifle odd. Running the Selftest, the bed moved forward, then backward, then errored with "Axis Length, Y Axis". I then turned it off and back on, noticing that the Y-Axis was now at -0-. Ran selftest again with same results.
I then moved the bed, again with Move Axis, to 105. Same result: the bed moved forward, then backward and stopped.
I tried again, this time moving the bed to 210. This time the bed moved backward, then forward, then backward again and errored out with the same error.
At this point, I have no idea what to do but have made the following observations:
1) The front pulley assembly (Y-belt-idler) is at least 1-2mm away from the frame.
2) If I push the bed back manually all the way from the front, it feels like it catches about 2-4cm away from the front and the resistance needed to push it back changes fairly dramatically about 8cm away from the back. (It gets much harder to push.)
3) The belt moves to the left of the pulley (if looking at it from the front). I slid the belt to the right (there's about a 1-2mm gap) and as I pushed the bed to the back, it slid to the left. This tells me that something may be slightly out of alignment, possibly due to the front pulley bracket being loose?
Finally, and I have no idea if this has anything to do with it -
1) The room where the problem popped up is a good bit cooler than the room where we first started printing.
2) Something strange happened occasionally as I was using the Move Axis. It would go all the way back, then grind. The extruder head would then go up and to the right just a bit and the readout would jump from -4 to 1.4. Almost like it was trying to adjust itself.
Re: Selftest Y Axis Length Failing
I just had similar symptoms on Y, and it was confusing since it had passed X and Y several times already. Then I noticed the drive pulley setscrew had come out, causing it to slip intermittently which caused shifting layers and length errors during calibration.
Its come out a couple more times after that even when fully tightened so I'm going to hit both of them with some loctite.
Re: Selftest Y Axis Length Failing
Thanks for the help. Can you tell me where the set screws should be? I'm looking on the post coming out of the motor and see 2 holes with nothing in them. Is that them, or somewhere else?
Thanks,
Chris
Re: Selftest Y Axis Length Failing
I think curtis.c2 means these screws.
Also, make sure that the screws that hold the motor are not tightened tight.
I saw a video where the engine's screws were so tight that the motor bracket had become deformed.
As a consequence, the motor shaft was no longer perpendicular to the drive belt.
With a winding motor shaft, the belt will wriggle and bend against the side of the pulley.
This also applies to the X-axis stepper motor.
Bear MK3 with Bondtech extruder
Re: Selftest Y Axis Length Failing
I think curtis.c2 means these screws.
Did you miss one image?
My guess is this one:
The red arrow is pointing at the grub screw, it is hard to see unless you look closely.
Re: Selftest Y Axis Length Failing
I think curtis.c2 means these screws.
Did you miss one image?
My guess is this one:
The red arrow is pointing at the grub screw, it is hard to see unless you look closely.
thats the one. My main set screw (on the flat part of the shaft) had worked itself out, and only the secondary screw was left holding it.
Re: Selftest Y Axis Length Failing
I’m having the same exact problem with a pre-assembled mk3. Did you find a fix for this? Really expected better quality actor forking $1000 for this ....