MMU2 - will it ever work reliably ?  

Re: MMU2 - will it ever work reliably ?

Hello,

i have my MMU2 for a week now and i didnt have any problems so far... i didn't even have to troubleshoot something at all, just built it up and it works. I never opend the MMU Idler or had skipped layers. For me it works reliable. I hope it stays that way.

Greets
Daniel

Re: MMU2 - will it ever work reliably ?

Hi there, I'm 100% with you marc.o2!

For the vote, I think it's important to know the printer MK2.5 or MK3 , it's seem the MK2.5 users have most trouble than MK3 user....

Re: MMU2 - will it ever work reliably ?

MK3 user with the MMU 2.0. I spent 3 months of tweaking and troubleshooting with the unit before I asked Prusa for a refund this week. Wasn't able to get a single successful print.

Every print failed by having a missing layer or stripping the filament. I've used Push Plastic ($30 a roll) PLA and Inland ($15)

Re: MMU2 - will it ever work reliably ?

Hello,

I've got a mk2.5 + MMU2 since 1week now, and I'm trying to have only one successful print...without success. My mk2 then mk2s then mk2.5 worked flawlessly (for more than 2 years now), and I often do some colorprints (the old way, with M600) and this worked very fine. I even print colored object with different colors on the same layer (everything done by hand).

I was expecting a lot more from this MMU2 and I must admit I'm very disappointed. We are some french friends who have this mmu2 unit and we are all facing a lot of problems, too much problems.

I hope I will find a way to have at least one print working...I'm still reading those forums and experimenting to find a way to make the mmu2 work as it should be.

P.S: by the way, all my tests are done with 2 rolls of prusament and I'm using standard configurations (mk2.5+mmu2) with slic3r PE 1.41.1. Firmware 3.5.0 (1.0.2), extrudeur R3/B7

Re: MMU2 - will it ever work reliably ?

What really frustrates me about the MMU 2.0 is the cost and the experience. For $300 I'd expect a product that works reliably out of the box. I don't recall seeing a single post or seeing a single YouTube video with someone sharing a consistent perfect experience with the MMU.

Think about the contents that come in the MMU 2.0 packaging. With the MMU you get some steppers, prints, bearings, and hardware. Compare the $300 to $600, the cost of a MK2S, and then you'll realize that you're getting very little for what's being charged. Simply put, I'm not seeing the value with the MMU 2.0 if I cannot get a single dang print out of the thing after 3 months of trying every mod that seems to be the flavor of the day.

I'm very disappointed with this product and I feel cheated. Support hasn't been helpful and I truly feel like I've been taken advantage of after giving them my money nearly a year ago and getting this.

Re: MMU2 - will it ever work reliably ?

I asked PRUSA support if they could exchange my MMU with a unit assembled and tested by PRUSA but they declined. The only thing they provide is support in troubleshooting.

I´m wondering, if the reason why they are refusing to deliver assembled and tested MMU2 is the fact that they would need to give a guarantee for the product to work, but as long as the customer has to assemble the MMU2 himself they do not need to provide any guarantee as they can always blame the customer.

Re: MMU2 - will it ever work reliably ?

wasted another 3 hours troubleshooting this morning of which 1 hour together with the support

Re: MMU2 - will it ever work reliably ?

I asked PRUSA support if they could exchange my MMU with a unit assembled and tested by PRUSA but they declined. The only thing they provide is support in troubleshooting.

I´m wondering, if the reason why they are refusing to deliver assembled and tested MMU2 is the fact that they would need to give a guarantee for the product to work, but as long as the customer has to assemble the MMU2 himself they do not need to provide any guarantee as they can always blame the customer.

I think there are machine variables at play too. When Prusa processed my refund they asked me for my observations. They had some suggestions on some things to try to increase the probability of success. One thing they suggested was drilling out the extruder body to widen the filament path to decrease the drag on the filament. Their other suggestion was replacing the thermal paste on the heatbreak.

Still pretty frustrating that its extremely unlikely to have a good out of the box experience.

Re: MMU2 - will it ever work reliably ?

Hi dryja123,

My impression is also that the problems come from having too much friction on the filament inside the MMU.
When trying to push the filament thru the MMU by hand, it is quite difficult and requires quite some force. The annoying thing is that when trying this
MANUAL load with different filaments, some filaments pass without requiring much force while others require a LOT of force. This seems to indicate that the holes for the filament are too tight and depending on the filament quality and its tip (is it well cut, does it have a small blob ?) the filament gets stuck.

I was already thinking that the MMU would work better,having bigger holes and without the PTFE tubes but having a much smoother inside part finish (Ex. ABS smoothed with Acetone) such setup would reduce friction of filament and eliminate any potential edges inside the holes where the filament could get stuck.

Re: MMU2 - will it ever work reliably ?

People in this forum are usually very helpful (sometimes even more helpful than the prusa support).
The problem is complaining about something that it doesn’t work and showing images of parts with skipped layers. How can anyone help you that way?

I now there should be a guide from pusa out there but there isn’t. So use the search option of this forum or ask at least for help because a lot of people here have a great working mmu which produces superior prints compared to eg Palette 2 which costs more than double. I am sure we can help everyone to get there too.

What filament (brand) are you using?
What are your prints settings?
What are your ramming settings?
How do your tips look (fotos)?
What are the diameters of your tips?

Re: MMU2 - will it ever work reliably ?

People in this forum are usually very helpful (sometimes even more helpful than the prusa support).
The problem is complaining about something that it doesn’t work and showing images of parts with skipped layers. How can anyone help you that way?

I now there should be a guide from pusa out there but there isn’t. So use the search option of this forum or ask at least for help because a lot of people here have a great working mmu which produces superior prints compared to eg Palette 2 which costs more than double. I am sure we can help everyone to get there too.

What filament (brand) are you using?
What are your prints settings?
What are your ramming settings?
How do your tips look (fotos)?
What are the diameters of your tips?

I think you touched on a few things that I really disliked about my experience with the MMU 2.0

First, you touched on cost VS the Palette. The MMU 2.0 is still $300 for some steppers, hardware, a board, and some prints. Don't forget that you have to take the time to assemble it. I don't know how you value your time but the time I invested in assembly and troubleshooting (3 months) made the MMU 2.0 exponentially more expensive than the Palette.

Second point you touched on support. The MMU doesn't work out of the box (after assembly technically) and you're stuck to finding a magic spell to get it to work. After you found the magical spell then you'll need a miracle to be able to duplicate those results. After you've achieved that you can restart the process on new types of material. It's incredibly time consuming and frustrating.

At some point you really need some official support and communication from Prusa so we can stop trying the next flavor of the day when it comes to "fixes". This really feels like a product that was dumped on us to figure out how to get it to work.

Re: MMU2 - will it ever work reliably ?

This really feels like a product that was dumped on us to figure out how to get it to work.

I agree with you 100% on that.

But the thing is I think we have figured it out now. :geek: At least for most PLA filaments and BVOH. I (and others) will start testing flexibles and other materials soon.

Re: MMU2 - will it ever work reliably ?

Second point you touched on support. The MMU doesn't work out of the box (after assembly technically) and you're stuck to finding a magic spell to get it to work. After you found the magical spell then you'll need a miracle to be able to duplicate those results. After you've achieved that you can restart the process on new types of material. It's incredibly time consuming and frustrating.

At some point you really need some official support and communication from Prusa so we can stop trying the next flavor of the day when it comes to "fixes". This really feels like a product that was dumped on us to figure out how to get it to work.

What about all the people who purchased it and are not posting here with problems? Did they all just happen to know this "magic spell" to get it to work?

I do not have mine yet, but a lot of people have it and very few are posting about how hard it is to make it work. That tells me that a lot of people did not find it hard to make it work. Not saying it is your fault, just saying the majority are not having problems, else they would be posting.

Re: MMU2 - will it ever work reliably ?

when you finally get your mmu, spend most of your time cleaning out the spots the TPFE tubes go. I swear the biggest issue for me at least was filament movement. (it has to back out as good at it goes in)

I still have 100% stock (prusa pla) settings with a mix of inland/prusa/amazon pla. my pva works with default bvoh settings.

the only thing that is not on my printer is the cover for the 5 PTFE tubes going into the mmu and I never changed my hot end carriage. I also just use a stainless steel shaft to hold my normal 5 filaments.

Re: MMU2 - will it ever work reliably ?

What about all the people who purchased it and are not posting here with problems? Did they all just happen to know this "magic spell" to get it to work?

I do not have mine yet, but a lot of people have it and very few are posting about how hard it is to make it work. That tells me that a lot of people did not find it hard to make it work. Not saying it is your fault, just saying the majority are not having problems, else they would be posting.

I'd be curious to know how many people ordered the MMU and posted here with issues. Also, the amount of people who lurk or are posting on the Facebook group / contacting support directly. I wouldn't say that all of the people in the world who are having issues are posting just here, that'd be silly. To say that the MMU 2.0 is not an out of the box smooth product would be silly.

Re: MMU2 - will it ever work reliably ?

My MK2.5+MMU2.0 working fine after around 2 months of debugging filament tip issues. I'm very happy with my MMU2.0.

Too bad my Palette 2.0 will be shipping this month and don't know what to do with it. I bought Palette 2.0 because I already given up MMU2.0. Probably I'm going to buy another printer for Palette 2.0.

Re: MMU2 - will it ever work reliably ?

Too bad my Palette 2.0 will be shipping this month and don't know what to do with it. I bought Palette 2.0 because I already given up MMU2.0. Probably I'm going to buy another printer for Palette 2.0.

😆 That seems like a very carefully engineered excuse to buy another printer.

Re: MMU2 - will it ever work reliably ?

I'd be curious to know how many people ordered the MMU and posted here with issues. Also, the amount of people who lurk or are posting on the Facebook group / contacting support directly. I wouldn't say that all of the people in the world who are having issues are posting just here, that'd be silly. To say that the MMU 2.0 is not an out of the box smooth product would be silly.

It actually doesn't matter. All PR products which I purchased were couple steps ahead of it's final release. Every part is open source, easy to get, easy to modify. All of them got improved over time together with this great community. Asking for numbers doesn't help anybody. If you don't like this approach, you will never be happy with PR products.

I can tell you my numbers. For under $2k I have two machines now at home. One is enclosed printing nearly any material what we have on the market 24/7 and the other one is 5x multi color and soon 5x multi material (waiting for software updates) printing crazy/funny stuff. It wasn't possible before PR and still there are not many competitors who can deliver same quality for this price.

I think the main point you can already see in this poll, the MMU2 can work reliable. We can print something which we couldn't before. It's definitely not easy to setup and not easy to maintain (like plug and print) but it is good enough to be sold. And it's definitely an improvement from MMU1.

Re: MMU2 - will it ever work reliably ?

People in this forum are usually very helpful (sometimes even more helpful than the prusa support).
The problem is complaining about something that it doesn’t work and showing images of parts with skipped layers. How can anyone help you that way?

I now there should be a guide from pusa out there but there isn’t. So use the search option of this forum or ask at least for help because a lot of people here have a great working mmu which produces superior prints compared to eg Palette 2 which costs more than double. I am sure we can help everyone to get there too.

What filament (brand) are you using?
What are your prints settings?
What are your ramming settings?
How do your tips look (fotos)?
What are the diameters of your tips?

Hi flaviu,

Thanks for your answer.
So far I did my troubleshooting together with PRUSA support and using the information available on the forum.
Like I said already before, the issue seems to come from too much friction on the filament (from entering the MMU to the extruder)
I tested this by pushing and retracting the filament by hand.
The filament loading proceeding fails at varying length of filament insertion: once it is inside the MMU other times it is somewhere in the Orange PTFE tube, but rarely at the same position.
Regarding your questions :
- brand of filament :Janbex,Verbatim,Prusament
- Print settings : I never managed to get a print done. I´m stuck at first layer calibration which fails due to the fact that one or the other filament is always getting stuck. Yes it is not always the same filament-position
- Ramming settings : never touched them yet. still factory
-look of tips : I don't have fotos, but I noticed that every minor-minor deformity on the tips when inserting filament will make the load process fail.
It takes me multiple try's to cut the filament tips so that they will pass thru the MMU.
- diameter of the tips : I haven't measured yet, but it is clear that even the slightest brim when cutting the filament will prevent the loading procedure.