Loose shaft causing "Idler cannot home"
When I assembled my MMU3 (with MK3S) I noticed the rightmost of the shafts that holds a bearing in the idler to be very loose. This happened in 4. Idler Body Assembly (Step 4)
I even left a comment on this step (with no answers yet):
The last shaft (marked dark red in the instructions) did not engage and moved very freely. The other shafts seemed to "stick" when inserted completely.On my first testprint the shaft got completely loose and the bearing fell out mid-print! No idea how to fix this. Maybe incorporate a way to fix the shaft?
Now I had multiple fails because of the shaft coming loose.
The relevant help-page is this one: Error 04125
I am looking for a way to fix this. I am hesitant to just use glue to fix the shaft. Any ideas or similar experiences?
RE: Loose shaft causing "Idler cannot home"
Did you print the parts as it sounds the printed hole is to big
Please help me out by downloading a model it's free and easy but really helps me out https://www.printables.com/@Hello_474427/models
RE: Loose shaft causing "Idler cannot home"
I had the same problem, except mine didn't fall out during a print! I noticed it when assembling the idler and it was the same bearing position as yours. my solution was to go through all the shafts I had to hand (some spares, some from the old MMU2 idler) until i found one that stayed put. For now its working but I may reprint the part to see if I can improve it a bit.
RE:
Did you print the parts as it sounds the printed hole is to big
Yes I did. The print came out very nice. The other holes seemed to work as intended. Just this one hole seemed too loose.
my solution was to go through all the shafts I had to hand (some spares, some from the old MMU2 idler) until i found one that stayed put.
Thanks, I will check if i find another shaft that fits better.
For now its working but I may reprint the part to see if I can improve it a bit.
Please let me know if reprinting helped.
RE: Loose shaft causing "Idler cannot home"
I just compared the two holes in PrusaSlicer (see attached screenshot). The one that feels too loose is actually bigger! It is just a 0.150 mm but it might make a difference.
So Prusa might want to update their model before we reprint!
RE:
I had the exact same problem with that exact shaft you mentioned. The shaft kept slipping out and causing problems.
I wanted a fix that would not alter the idler in any way.
So, I made a foam "plug" that I "punched" out of a piece of neoprene foam that was 1/8 inch thick. I have a hole punch set and I made a plug that was slightly bigger than the hole size. I then stuffed it into the hole so it was a tight fit. It doesn't look pretty but it's been working for the past two weeks without any signs of failing. The good thing about this mod is that it would be easy to remove the plug with a miniature screwdriver. It might ruin the plug but I can make another very easily.
It might be hard to see in the picture but that's the piece of foam that I stuck into the hole. I don't think you would even need a hole punch. Just cut the foam in a circle that's bigger than the hole and stuff it into the hole.
Works great for me. And no need to reprint the idler, and disassemble the MMU3 to redo the idler installation.