Works well BUT ...
The loading of the MMU3 is an insufferable chore, it puts me off changing filament because loading is such a hit and miss affair - I am so close to removing it ....
Does anyone have any mods that make contact with the feed guaranteed instead of the poking and prodding around that is made even harder when it is all buried inside the enclosure as mine is - because you cannot see jack all ...
I read about making sure the guide tubes inside were close to the hobs but that requires a tear down that I'm in no hurry to do.
Yes I know about filament straightening and 'shaping' but it really doesn't help the hit and miss business.
There's no way to abort pre-loading either you're forced to wait on a timeout
RE: Works well BUT ...
there are mods that straighten the last 2 cm of the PTFE tube before the MMU. Works well enough for me (not perfect, though).
And yes, going back into a box is probably not an uncommon fate for MMUs ...
RE: Works well BUT ...
I load my MMU3 very reliably, by pushing from my (Un)original Drybox on top of the enclosure, through the buffer (with the loading fork inserted), and into the MMU. I use the small tool that rounds the end of the filament, and ensure there is no bend in the last 50 mm. Other than that, there's no reason for it to fail.
I was very careful to make sure the PTFE were pushed ALL the way into the MMU3 as the directions (and the comments in the instructions) stated. That's the most likely cause for your difficulties. You don't have to take anything apart to check that out - look for the step where it says the end of the tube should be visible from inside the MMU. I remember it did take quite a bit of force to get it all the way in...
Prusa MK4 since Jan 2024, Printables: @MikeB_1505898
RE: Works well BUT ...
I'll see what the phone can see - right now it is in an enclosure so you aren't getting Mk1 eyeball on anything in the MMU. I have been trying through the buffer - I take the reel out and fish for the feeder catching the filament but it is hard to detect the point at which that occurs or how much force - then you get the curly filament sticking up out of the selector mech .... rinse and repeat .... I'll spend some time on it once I get my CoreXY back into service but I would rather not have both printers down
RE:
I assume you don't have the hinged lid for the enclosure - print this and you'll never be sorry you did! https://www.printables.com/model/273426-hinged-lid-for-adding-mmu2s-to-original-prusa-encl (it's also perfect for the MMU3, and helps with moving the printer around or out of the enclosure as well).
The other thing you can do is rotate the MMU3 a bit upwards - detach the bottom 2 clips and pull it up and rotate forward at the same time. I can get it to rest on the printer frame in that position where I can more easily see the filament exit from the PTFE.
Prusa MK4 since Jan 2024, Printables: @MikeB_1505898
RE: Works well BUT ...
I don't have that - but I will soon, I appreciate that link, was unaware -how does that handle the buffer ?? - I think mine would be more than happy to slide off.
RE: Works well BUT ...
Yeah, there are multiple ways to handle the buffer - mount it to the sides of the enclosure, or inside the enclosure, or in my case I put it on the back: https://www.printables.com/model/1180632-vertical-buffer-mount-for-rear-of-unoriginal-drybo. If you do that you really need the loading fork so you can push from inside the drybox, because the buffer cartridges are not easily accessible.
Or make a hanger for the buffer to temporarily hang it on the side of the enclosure if you need to lift the lid.
Prusa MK4 since Jan 2024, Printables: @MikeB_1505898