MMU2S coming, how to prepare now?
I built my MK3S+ from a kit a few months ago and I'm really enjoying it. I decided I wanted to be able to do multicolor prints, so I've got an MMU2S kit on order. To prepare, I've been reading a bunch of threads here (this and this were very helpful) . It looks like there are several mods that could be useful, so I want to get all those printed before my printer is out of action during the MMU assembly.
Here's the mods I'm planning to print now to prepare for the MMU. Advice from experienced MMU owners would be very appreciated!
- PTFE M10 passthrough adapter
- Modified selector with magnet
- Modified IR sensor holder
- Gravity spool holder with the No Clunk Modification
This redesigned extruder mod has lots of good comments too. I'm considering to print that too.
Are there different mods I should consider? What else can I do now to prepare for the MMU that should be arriving in a few weeks?
RE:
I've recently added an MMU2S to my printer, and have had a thoroughly successful experience with it. I did do a few mods, some I suspect were not worthwhile.
PTFE M10 passthrough adapter - I printed the same one you linked. I've very happy with it. I suspect that this does help as it keeps your filament in the PTFE tubs longer, reducing overall friction.
Modified selector with magnet - I printed a several of these. For some reason, I had substantial trouble getting it to stay stuck to the bed. I had to print it 4 or 5 times before it didn't fail. No idea why. Never had trouble getting stuff to stick. There was something demonic about this thing. In the end, I think it was a waste. The metal ball isn't magnetic, so the magnet does NOTHING to help. I vaguely recall there being a physical feature to helps marginally with assembly with the selector, but otherwise, I think it was a waste.
I did not print the modified IR sensor. I had no issue using the one that came with the kit.
I almost printed the gravity spool holder, but decided against it. There were a lot of parts involved, but people did seem to love them. But I also saw that several people had fallen out of love with them because the plastic printed springs wear and break. They were constantly printing new springs. Maybe they needed to explore different plastic to print with? Instead, I printed these:
MMU Slot Buffer
Numbered Slots - PC4-M10
Edit: I got the gravity spool holder confused with auto-rewind holders.
The kit ships with 4mm OD and 2mm ID PTFE tubes. I replaced it all with 4mm OD x 3mm ID tubing. The larger inner diameter is critical between the extruder and the selector. When switching filaments, the extruder does a multi-step process:
- Pull the filament out - This leave a long, stringy tip. Bad.
- Shoves the filament back into the hot end. This crams the stringy tip back into the filament, forming a head.
- Repeat a couple of times to eliminate the stringy.
- You can configure the number of rams/dribbles used in PrusaSlicer if you need to.
The problem is that the tip reforming process often makes a bulged head at the end of the filament. Having a 3mm ID instead of a 2mmID tube helps a LOT with changing filaments. I suspect that the 3mm ID tubes is the single largest contributor to my success with the MMU. This is the tubing i bought: https://www.amazon.com/dp/B07B8CT1YH?ref=ppx_yo2_dt_b_product_details&th=1 25ft of it was juuuust enough for me.
What type of enclosure do you have the printer in? Mine is in the Lack V2 enclosure. Reaching the MMU2S controls is difficult. I suspect that printing this would have been beneficial, but I'm not going to take the time to go back and make changes: https://www.prusaprinters.org/prints/140-mmu2-underslung-control-panel-mount
RE: MMU2S coming, how to prepare now?
Meant to add this to my previous post, but too late to edit now. Watch this video:
Some of the stuff may feel like, "Duh," to you. Overall, there's a lot of great information in that video and I have referred to it several times after the upgrade.
RE: MMU2S coming, how to prepare now?
Thanks so much! That's really helpful advice. I plan to watch that Theory of Operation video again and take notes on it because there were so many useful tips in it.
What type of enclosure do you have the printer in?
I'm not using an enclosure. I have 2 IKEA Lack tables stacked up and the printer is on the top one. My plan for the MMU is to have the spools of filament on the lower table surface and feed up from below. I saw a picture of someone else's set up like this using the gravity spool holders.