Selftest Error Axis Length - Y Axis
Yesterday I finished assembly of the i3, ran through self test and calibration, then printed 2 files. On the 3rd file I noticed errors in the lines it was drawing. Today I decided to re-run the Wizard calibration. The selftest now fails on the Y Axis selftest.
I tightened the belt, there is definite tension in it. I checked the gear alignment to make sure the belt is in the middle of the gear/pulley. I moved the platter back and forth and don’t see anything stoping the platter.
My firmware is at 3.5.3
Could this be an issue of the spacing of the bearings on the left side? They’re what is stopping the platter on the Y Axis. I haven’t seen mention of how far they should be apart.
What else can I check? Any suggestions what the issue could be?
Thanks, Doug
RE: Selftest Error Axis Length - Y Axis
I upgraded to the latest firmware, 3.7.0, but the problem still occurs. I also verified that the platter goes back and forth to the limit of what the bearings will allow, they touch both rails. I put my finger on the platter while its moving to add resistance and I don’t detect any slippage in the belt or gear on the motor shaft. I tightened the gear on the motor shaft to be sure.
Could this be an issue with the motor or logic board?
Thanks, Doug
RE: Selftest Error Axis Length - Y Axis
No it should not be a software bug.
I think you should look for any part that prevents a full motion in the X, Y and Z directions.
It can be a cable tie that sits wrong, a cable that is placed incorrectly or something else that prevents a full motion.
In the Y-direction, the linear bearings determines the length of the movement.
In the X-direction, the extruder is supposed to meet the motor-holder and X-end idler and in the Z-direction, the motor-holder and X-end idler are to meet the screw heads in Z-axis top parts.
Bear MK3 with Bondtech extruder
RE: Selftest Error Axis Length - Y Axis
I found the issue! The Y Axis pulley was loose. I had checked the screws on the pulley and they felt tight enough. But in my latest test I noticed the screw that was centered on the flat spot was off center. Apparently there was a bur on the threads, I had to tighten it further to make better contact with the flat portion of the shaft.
Thanks!
RE: Selftest Error Axis Length - Y Axis
Flat First: Pulleys must be tightened flat-first. Start with the pulley free to spin on the motor shaft. Locate a set screw and align it with the flat on the motor shaft. Slowly tighten the set screw until it fully contacts the flat surface. The screw should be dead center on the flat. Now tightened the set screw to spec. Once you have tightened the flat set screw, not tighten the jam set screw. Once tightened, never retighten the flat set screw unless the jam screw is first loosened.
RE: Selftest Error Axis Length - Y Axis
New to the community and just assembled my MK3S and have the same error during the self test, the Y axis length. The hot plate moving forward and left bearing hits the stop which cause a loud noise (motor trying to spin) before finally turning direction and moving the plate back. At this point the error message comes up for Y axis length. Done only the XYZ Calibration and ut works fine and passes with Ok.
I have check for obstructions when unplugged and the bearings move all the way to the front and touch the stop. I also checked belt tension, pulley on the motor shaft, no other obstacles . I also loosen the U-bolt for the front bearing and pushed as far back as possible but not enough.
Any ideas what to check next?
Thanks!
RE: Selftest Error Axis Length - Y Axis
When Y homes, it is a bit disconcerting at first, but it is normal for the bed to hammer a few times. If the Y bearings can contact the rod supports, that's all it should take. And Y bearings should be in the middle of the frame slot, a space at either end.
Check the LCD status display for crashes. Once in a while slightly loose cables or other things grab the sled and stall the motor, U-bolts hit the frame, etc.
And the next common problem is a loose belt slipping over the gear; or the gear spinning on the motor shaft.
If you didn't tighten the set screw on the flat before tightening the jam set screw, go back and fix the gears. Repeating the procedure... lol.
Loosen both screws until the gear can spin freely: align one set screw to the flat, slowly tighten it until it is seated and perpendicular to the shaft. Torque to spec. Then tighten and torque the jam screw. If not done in order, flat first, gears can seem tight but will still spin. You can watch it happen, so it's easy to check visually, too.
RE: Selftest Error Axis Length - Y Axis
Thanks for the prompt response.
Embarrassed to say but it was the belt tension that caused my problem. I thought it was tight enough by the tests done following the guideline but apparently not enough 🙂
Everything works fine now!