We’ve been having plethora of issues with M300 Dual. Here’s another one. Printer has clocked in 4600h at the moment.
For many months we’ve been having issues with errors pertaining to failures of the device while performing various movement related procedures - loading/unloading, axes test most notably. The issues would come up with an error saying that there’s a problem with either X or Y axis optical sensor or (only lately) with an information that axes maintenance is needed. In general the extruder movement seems a bit too tough but I can’t really tell cause thatis the only printer that I have.
So, I finaly sat down to take care of it. Optical sensors are 100% fine. Firmware updated, no issues with extruder. I narrowed the issue down to axes misalignment. Here are two readily obvious issues:
- When extruder performs homing and goes to bottom left corner there’s good chance it gets stuck there and the engine has not enough power to move it resulting with X/Y sensor error.
It’s not a 100% chance. Sometimes it performs a full axes test without being stuck. However, when it gets stuck it’s notably harder to move it from this position (power off), but then it usually moves sort of freely.
- When extruder moves directly along either axis there’s a small chance increased friction issue comes up and extruder stick-slips with a noise.
I’ve spent nearly 2 days disassembling and reassembling the whole thing, cleaning all the axes, cleaning bearings, everything and I’ve come to the conclusion that the 8 self-aligning bearings are at fault. 7/8 of them have hard time moving around, especially from the neutral position. The rotation is fine, but the yoke movement is obstructed. And I mean in some cases catastrophically! I cleaned them as much as I could from black residue, lubricated them and it reduced friction a bit, but not enough.
I also used the distance clips intended for axes alignment check. In general the top right and bottom left clips show a 2mm gap but even after fiddling around with the setup and reducing all gaps to 0 the very same issues persisted. Only then I decided to disassemble the printer.
I think this is the root cause also because there’s a clear clicking sound then I move the extruder around at midplane, which is probably made by the only fully working bearing when it aligns the axis according to forces acting on it.
Another thing that points to this being the issue is that the extruder exhibits the highest movement resistance at the 4 corners and moves more freely in the center.
Side note! Each of the 4 “big” axes plain bearings along the edges of the printers top comprise a housing and a single brass bearing. Is this normal or the longer housings (along front and back of the printer) should contain two bushings each? Cause it definitely looks like they should!
So I have two requests to you guys:
a) Have you ever experienced similar issues and what helped you out?
b) Could you please provide the numbers/source of those two catalogue items so I can buy them at some 3rd party and replace them? Because you do not offer them off the shelf…