We can now move on to loading the filaments in and printing the test object! But first;
⬢Please prepare at least five different PLA filaments and cut off the ends to form a round sharp tip on each - as seen in the picture.
⬢The filaments must have a sharp tip in order to load properly into the MMU as well as into the printer. If the tip is deformed, bent or larger in diameter, it won't load properly.
⬢Inspect the last 40cm (15") of each filament. Make sure there are no dents in it. Sometimes, if filament got jammed before, the pulley wheel makes an indent in it. This part of the filament can no longer be grabbed and moved by the MMU unit and must be cut off.
⬢If the filament end is bent, straighten it. It must be perfectly straight.
Use only high-quality filament with guaranteed low diameter deviation. In case you have filament loading / unloading issues in the future, re-visit this step as well. Make sure the filament is dried up. Moisture-sensitive filaments can be problematic during the MMU operation.
There should be a 5 color option for the sheep. Not much of a first flight if you only check two of the colors. Especially since each one of the filiment pathways needs to work in order to function.
I had poor luck trying to create a sharpened tip as described here. Instead, I found that a very long angled cut along the length of the filament (basically a long 45 degree) single cut allowed me to easily load all 5. Look at the recommended filament tip cuts for the Prusa Mini and that is how I cut mine.
I was having trouble getting the ends of my filament to be straight enough to load into the MMU. I used my old piece of PTFE that I took out of my hot end to help bend/reverse the curve... I would stick my spool into the end of it and flex it oposite the curve, and push the filament in and out of the short piece of tubing to help get it straight.
I also had to occasionally just open up the top of my MMU and manually make sure the end of the filament cleared the edge just before the selector while pusing in from the buffer/cassette end. After a successfull print, all the filaments gave a really nice tip and they had less trouble loading into the MMU.
