MMU3 Setup and First Print Experience
After about 2 weeks, and over 1000 tool changes with no faults, I am ready to say that I have my MMU3 setup dialed in and ready for full production.
Tl: dr; For those who are still waiting for theirs, and may have had trouble with the MMU2 in the past, I can say that this was much easier to troubleshoot and to get dialed in, even for stringy materials like PETG. I did encounter one concerning issue, but was able to work around it and can mark it (tentatively) resolved.
The Good
* The filament buffer is much better suited to purpose, and easier to position and adjust than with the MMU2. I abandoned this early on with my MMU2, but actually prefer the stock buffer now to the spool rewinders that I had been using.
* The IR sensor chimney tower has an additional screw for adjusting position that makes it easier to make (and hold) precise adjustments.
* The main display now shows the IR reading through the process of filament load during print, so you can quickly identify when the filament is "shaky" about triggering the IR sensor and adjust accordingly *during the print process*, so you can burn in without printing dozens of headless sheep.
* The double-bladed cutter is much better at clearing away even thick filament strings in the path of the selector, which is very helpful for preventing jamming. OTOH, especially as you burn in, you may wind up with a LOT of filament strings and nubs in and around the works: it helps to have a small vacuum on hand to get rid of the detritus between prints.
* The unit has a helpful notch to let it rest forward for easy maintenance and troubleshooting, without running the risk of snapping the part that latches to the printer at the worst possible time.
* Most of the firmware issues really do seem to be fixed. There are very few problems that I encountered that were not recoverable (especially useful with materials like PETG), and I can easily switch back and forth from single mode to multi mode w/out bizarre faults.
The Meh
* The FINDA is very sensitive to the presence of filament strings. The "fix" here is to adjust your settings to try to maximize stringing reduction, and to set the FINDA at the highest possible point where it will still trigger in the presence of the 1.5MM hex key. Most of my time was spent finding my FINDA sweet spot and ensuring that the screw on the collar was tight enough to keep it in the position that I set for it.
* The idler position is maintained by the tension on the screws on the lid of the unit - these need to be tightened to the point where there is no wobble at all as the idler changes position, or you could wind up with odd feed errors.
* During an error condition, you don't have the option to use the left / right buttons on the MMU unit to move the selector. This can be quite maddening for heavy filament jams, as the selector will automatically rehome as a part of its "retry" sequence, and can, as a result, drag jammed filament along with it. The alternative is to gently rotate the motor shaft so that your selector is either in a "neutral" position on the far right of the device, where the jam can be cut and cleared. I filed a feature enhancement request to be able to use the buttons ... hey, they had to save some goodness for the MMU4 😉
The Ugly
I encountered a very intermittent issue where the selector would actually fail to execute the re-homing sequence after a retry and forget its position, loading the selected filament into the air. My only guess as to why this would happen was that a power issue was either causing communication between the printer and the MMU or causing the MMU to lose state. The MMU2 had a very definite power problem that should be fixed with the MMU3. Unfortunately, I don't have enough of an electrical background to judge that claim, but I do know that since I hooked up a power supply directly to the MMU3, this issue has not recurred.
The Final Result
It works 🙂 It really works 🙂 This model had over 750 tool changes, and printed with no faults. Overall, definitely worth the purchase price!
Prusa is MK4S w/ MMU3 (formerly MK4 / MMU3, MK3S+/MMU2), 2 Prusa MINI+, Octoprint. PETG, PVB, (some) PLA.
RE: MMU3 Setup and First Print Experience
Thanks for the detailed first impression. It gives me hope that I made the right decision to stick with Prusa and not look elsewhere for MMU printing. Sadly I am still waiting for my order. I ordered the kit with pre-printed parts. I am looking forward to future prints.....
Rusty
RE: MMU3 Setup and First Print Experience
* The IR sensor chimney tower has an additional screw for adjusting position that makes it easier to make (and hold) precise adjustments.
This is what I had issue with my MMU2. For some reason, I struggled get it work for months after dozen reprint chimney and talked to multiple people that trying to help me and none worked. I yanked it off for good. I have MMU3 right now and plan to make a final install on extruder and I will see if I finally get it work.
RE: MMU3 Setup and First Print Experience
The bad design of the extruder/chimney body assembly has always been one of the big flaws, an exessive tension on the filament could move the chimney and disturb the IR probe, at the time I had modified the whole set, it had greatly improved reliability.
https://www.printables.com/model/1957-prusa-i3-mk3s-r4-extruder-mmu2s-with-path-through-
Glad to read that the MMU3 has fixed these problems, except for the hardware problems on the MMU2, the firmware was not perfect either.
I'm waiting for the MMU2/MMU3 upgrade kit for my MK4, curious to see how they have manage this with the nextruder.
MK4/MMU3 - VORON 2.4 350 Stealthburner
RE:
* The filament buffer is much better suited to purpose, and easier to position and adjust than with the MMU2. I abandoned this early on with my MMU2, but actually prefer the stock buffer now to the spool rewinders that I had been using.
Where should the filament buffer ideally be located? What effects does it have?
I am currently considering ordering an MMU for my MK4.
The printer is in a cabinet that consists of two parts. Below is the printer, above would be the filament rolls and the rest.
Next to the printer is only little space, upwards 22cm. The filament buffer could perhaps find space on the ceiling of the printer compartment.
RE:
@rainer-2,
The filament buffer gives space for the filament to retract without it tangling its spool or getting caught up in other filaments. I place this next to the printer in my setup, with the filaments on a shelf above the printer. I do believe, though, that the buffer could be placed horizontally above the printer as well. I have a picture of my setup here:
While the instructions call for the feeder wheels to be mounted at the back of the buffer with the filaments arrayed behind, the buffer is actually designed such that the feeder wheels will fit on the top or in the front, depending on where you need to place the buffer.
Regardless of how you decide to orient the buffer, you will want the feeder wheels to be easily accessible, as when you change filaments, you will want to be able to guide the filament from one side of the wheel to the other. In the pic below, the PTFE tube on the right leads to the filament spool, and the tube to the left to the MMU3.
Prusa is MK4S w/ MMU3 (formerly MK4 / MMU3, MK3S+/MMU2), 2 Prusa MINI+, Octoprint. PETG, PVB, (some) PLA.
RE: MMU3 Setup and First Print Experience
I am interested in hearing your experience of this - I've been waiting on an MK4 to see how others find that it plays with the MMU3.
I'm waiting for the MMU2/MMU3 upgrade kit for my MK4, curious to see how they have manage this with the nextruder.
Prusa is MK4S w/ MMU3 (formerly MK4 / MMU3, MK3S+/MMU2), 2 Prusa MINI+, Octoprint. PETG, PVB, (some) PLA.
RE: MMU3 Setup and First Print Experience
More results on the MMU3? It is out now for a couple of weeks and there are very minor issues reported. Is it realy that good? Please give some impressions
RE: MMU3 Setup and First Print Experience
More results on the MMU3? It is out now for a couple of weeks and there are very minor issues reported. Is it realy that good? Please give some impressions
Yep I love it it truly is multi color printing multi material with stock slicer that's another story
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: MMU3 Setup and First Print Experience
After about 2 weeks, and over 1000 tool changes with no faults, I am ready to say that I have my MMU3 setup dialed in and ready for full production.
Thanks so much for the detailed information; this sounds really promising and I look forward to receive my MMU3 upgrade kit soon to geht the MMU2S to work finally!
Best
Chris
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE:
No significant issues to report after the dial in described above. Latest is this 3D chessboard in PETG (attack boards still WIP).
Prusa is MK4S w/ MMU3 (formerly MK4 / MMU3, MK3S+/MMU2), 2 Prusa MINI+, Octoprint. PETG, PVB, (some) PLA.
RE: MMU3 Setup and First Print Experience
@rainer-2,
The filament buffer gives space for the filament to retract without it tangling its spool or getting caught up in other filaments. I place this next to the printer in my setup, with the filaments on a shelf above the printer. I do believe, though, that the buffer could be placed horizontally above the printer as well. I have a picture of my setup here:
While the instructions call for the feeder wheels to be mounted at the back of the buffer with the filaments arrayed behind, the buffer is actually designed such that the feeder wheels will fit on the top or in the front, depending on where you need to place the buffer.
Regardless of how you decide to orient the buffer, you will want the feeder wheels to be easily accessible, as when you change filaments, you will want to be able to guide the filament from one side of the wheel to the other. In the pic below, the PTFE tube on the right leads to the filament spool, and the tube to the left to the MMU3.
Tried mine with the cassettes facing up by rotating the whole assembly. This didn't work great as I did have a tangle with a couple filaments exiting out the back (Previously the bottom). If you move the cassettes to the top location on the separator plates, how are you mounting the short foot as that mounts into the cassette frame?
RE: MMU3 Setup and First Print Experience
Did you change any of the settings to get it to work with PETG? I'm having a fair amount of issues with PETG which I think is coming from poorly formed tips.