On the fence about the MMU2S
Hello,
I have a MK3 printer, I'm happy with it, and it's printing fairly well for my needs. I am considering adding the MMU2S (which would mean I would also be adding the MK3S upgrade kit that ships with the MMU2S). I'm a little leery of tearing down a working printer and I wanted to get input from the community before I decide to order or not. I put this one together from a kit so the teardown doesn't bother me, it's just that this one has been working great from the get-go and I don't want to tempt fate! LOL
One of the reasons I would like to add the MMU is to use up partial rolls of filament, I understand that the MMU can detect filament run out and switch to the next spool that's queued up. Is at least that function working?
I do a few multicolor prints that I sell but they are set up to color change on layers using each color only once, which means I can only kick them off when I am going to be home to swap the rolls, how reliable is the MMU if it's only doing four or five tool changes for the whole print and not reloading any colors? (ie: does it typically fail on unload or mostly when reloading a previously used filament?). It would be nice to kick off a print and not need to be there to swap rolls.
If I do purchase the MMU2S, would I be better off the order another MK3S printer kit to mount it on and leave my existing MK3 alone? I don't print a whole lot where I could really justify having two printers but I would hate to have this MK3 down and unusable for too long. Is the single material setting on the MMU2S reliable?
TIA,
Stephen
RE: On the fence about the MMU2S
So let's start with the working MK3 first. If the MMU gives you fits and you really need to print something that the plain printer can handle, simply disconnect the MMU from the Rambo and remove the PTFE to the extruder and you have a functioning MK3S. So worst case, it's easy to fall back.
There are two issues with the MK3S upgrade. The first is that there are reports (mine included) of parts of the extruder housing warping and melting with minimal use. There is a thread about it in the MK3 forum.
The second issue is the IR sensor and tower (the tower is unique to the MMU setup, but it does function just fine without the MMU). The big issue is that it is finicky to get calibrated and working correctly. My suggestion is to do the extruder upgrade, get through successful test prints with no issues, then assemble and add the MMU. That will save a lot of grief. Additionally, if your MK3 laser sensor was working correctly, then you lose the jam detection as the IR sensor simply detects the presence and not movement of the filament.
As to the MMU itself, getting it working and happy is the tough part. Once you find the correct combination for your setup it should work well, but getting there can be an ordeal.
Yes the spool join feature works, but no better/worse than the rest of the functionality. Be it one or a thousand, it's the tool changes where problems mostly occur.
If you can't make use of 2 printers, then I'd say getting a second printer just for the MMU is over kill.
In regards to using the MMU for the color changes you are already doing, if you can't slice the model to separate parts where you can assign different extruders to each section, then it would continue to function exactly as it does now with the added hassle of going through the MMU. There is a recent thread around here about doing layer changes automatically with different tools.
As far as tool change reliability goes, don't count on 100% hands off. If you get things running smoothly, you'll still have the odd change that needs help. I believe Prusa claims a 97% success rate in their testing which feels like a real number once you get it all sorted.
Based on your description, if you aren't going to change how/what you are printing, then I'd not get the MMU at this time. It sounds like it could potentially add a lot of headaches, but with very little (if any) gain.
RE: On the fence about the MMU2S
if I were to do it again.. I would stay non-s. put the mmu2 on. get one filament path working in single color one at a time, work out the kinks one filament path at a time. if you have extruder issues when you start changing colors while printing multicolor then consider putting the S extruder parts in.
it can work non S. but S does help with transparent filament at the extruder. for roll empty it uses the FINDA in the MMU to tell it the filament ran out.
it memory serves the MMU comes with all you need for S. BUT you still don't have to go S (make sure you keep your same firmware) mmu2 firmware last I looked was the same S or not.
when I got my mmu I did not change anything on my extruder (even the ptfe tube) BUT I didn't have any issues in the extruder until I put the S in. but they are worked out now.
I have a Prusa,therefore I research.
RE: On the fence about the MMU2S
Reading this morning, I came across this thread. I believe this is one of the threads gnat referenced?
It's exactly what I want to do and it sounds like it's not an easy option at the moment without hand editing the g code.
Thanks for the heads up on the melting issue, I had not read about that.
My infrared sensor has been turned off since assembly. So many users were reporting issues back then that I never enabled it. Only jam I've encountered was when the hot end extruder thermistor had an intermittent open in the wire.
RE: On the fence about the MMU2S
seems that should be pretty simple on layer change w/MMU, use the slicer cut function to split your model in two at the desired Z height, keep both parts, then select the appropriate extruder for each.
RE: On the fence about the MMU2S
I've not done a ton of multi color prints yet but I've enjoyed most of my time with the MMU2s however, for your use case I think it is worth a good hard look at the pallet 2. Cost wise it would save you vs a second printer and if your use ever requires a second printer you can move it over by switching one bowden tube.
RE: On the fence about the MMU2S
Thinking harder about adding a second printer since Prusa is offering free shipping on MK3S kits now, I think that's about as close to a sale as they ever get? There's been times that I wish I had a second printer.
RE: On the fence about the MMU2S
I probably would have gotten an MMU for mine had that also had free shipping.
RE: On the fence about the MMU2S
I guess I was farther over the fence then I though, I just ordered the MK3S AND the MMU2! LOL! I wanted to order some spare parts anyway.... that free shipping is sooooo expensive....
RE: On the fence about the MMU2S
You will not regret your decision PROVIDED you do not stress over the time it will take to get the MMU2 working properly. I am embarking on that journey now. I am taking the stress free approach of "when I get it working properly, things will be great, but I will learn a lot getting there". 🙂
RE: On the fence about the MMU2S
You will not regret your decision PROVIDED you do not stress over the time it will take to get the MMU2 working properly. I am embarking on that journey now. I am taking the stress free approach of "when I get it working properly, things will be great, but I will learn a lot getting there". 🙂
This is true. My MK3 is my first printer. I've followed the scene since it became a thing, but I've never delved into the nitty gritty as I didn't have the inclination or anything of substance to print. I finally bit the bullet and got my MK3 pre-assembled so I could get right to printing without worrying about what I messed up. Through adding the MMU and working through it's issues I now have a much better understanding of how all this works.
RE: On the fence about the MMU2S
I was advised to buy a kit when I ordered my MK3, they said that I would eventually need to service it and it's better to see it go together. It took me a long time to complete it (like 14 hours!) but I really enjoyed it and the instructions were great. I considered buying the mechanical bits off Ali Express and self printing the parts for another MK3 and MMU2S to save a few bucks but I really didn't have enough confidence in the Chinese knock-offs to think they were worth my time. Now I need to hit the flea markets for another AV cart!