[Closed] Giving up...  

Re: Giving up...

I have exactly the same impression: A lot of people complain about the MM upgrade on the MK2/S but nobody at Prusa actually cares.

If you read through the blogpost of the MK3 here: https://www.prusaprinters.org/original-prusa-i3-mk3-2-months/ you can see that they have invested a lot of time and effort in improving the MK3. However, since month there has been no word about the MM upgrade of the MK2/S. I would love to see the same dedication to the problems of the MM upgrade from Prusa, but I have given up my hope that this is going to change.

Looking at the “MK3 Multi Material upgrade kit”, it looks pretty similar to the MK2/S MM upgrade kit (if it is not actually the same). This at least gives some hope that they haven’t completely abandoned the MMU.

However, at the moment and at the current print quality of the MMU, this can only be recommended to users, who are willing to invest a lot of time into troubleshooting, but not to users who just want to print.

Re: Giving up...

I certainly don't want to fan the flames but are you using email for support or contacting them via chat from the store. I find that I always get someone to help or assist me in minutes from the store chat. They have also always been courteous and knowledgeable. I am sorry to hear your bad experience with your MMU, but I wanted you to know that they are available 24/7 via chat. I have seen a number of folks who did not know this, and I thought I would share. My MMU which I have had for 3-4 weeks now has been working fantastic, so they must have figured something out, they just need to get the parts and or information to you. Honestly, I have had fewer fails on my MK2S than on my MK3 so far. I wish you luck in whatever you decide to do, and totally understand how it feels not to be heard or addressed. Ironically its one of the reasons I went with Prusa over other vendors. Sad this has not been your experience.

Re: Giving up...

I‘m also done with the MMU and PRUSA as well!!!
Wasted so many hours of ‚not printing‘ and tinkering with something that is not developed well for standard and also advanced users! Was able to print at least 3-4 models with MM since MM launch and always as I thought that it’s now working I got clogging again and again!
Printed the last weeks always with my much cheaper CR-10 with no issues and trouble!
NO MORE PRUSA!!!

Re: Giving up...

I‘m also done with the MMU and PRUSA as well!!!
Wasted so many hours of ‚not printing‘ and tinkering with something that is not developed well for standard and also advanced users! Was able to print at least 3-4 models with MM since MM launch and always as I thought that it’s now working I got clogging again and again!
Printed the last weeks always with my much cheaper CR-10 with no issues and trouble!
NO MORE PRUSA!!!

I'm glad you can at least print but comparing a CR10 to an MK2+MMU is not exactly a apples to apples comparison. Kinda like comparing a four-wheel steering Acura to a 2wd Corolla. Nothing wrong with the Corolla, it's just not nearly as complicated, not is it trying to be. I would be upset as well, but at very minimum you have 3 good stepper motors, 4 complete Bontech gear sets, a brand new E3D V6.1 which all have inherent value and can be sold or simply used in another build. Keep in mind for me to buy those components alone without any of the other parts would be about $275 retail. So replace your MK2 Extruder and print away. The MK2 on its own clearly is better in components(quality and sophistication) as well as more flexible than a CR10. If you are not happy, I'm sure someone else would be happy to take up your project and you can recoup your costs. That's how I got my first MK2. I couldn't fathom waiting 10 weeks to get the unit, and I found one locally from a guy who thought he was dropping a dud on me, and still asking near retail. Once I undid all of his mistakes and rebuilt the kit it was awesome and has been running trouble free for well over a year now. I am in disbelief how trouble-free it is, other than replacing a PEI sheet or nozzle once in a while, its plug and play. Prusa, in addition, offered to cover any defective parts under warranty even though I was not the original purchaser. Anytime I need some assistance, the chat is always available via the e-shop. Again, I am sorry you have had a bad experience, but it may be time to move on. We often forget that there are much more expensive units on the market with no/marginal support which have the same exact issues we all do. Especially when selling to folks of all experience levels. One benefit I had was having a spare printer (Wanhao Duplicator I3) available to print parts if needed. I think everyone needs a backup or to print all of the parts and spares ahead of time, and have PTFE, bearings, nozzles, etc on hand as they are minimally expensive. I guess its comes down to your expectations. Good luck and hopefully we will see you back sometime in the future. Good luck and I hope you can reolve everythign amicably from a financial and functional perspective.

Re: Giving up...

Honestly spoken the MK2S is really not bad and very reliable but starting with the MMU was a big big mistake I painful regret.
Sure, the parts are good quality and as mentioned above I probably start to build my own printer with the remaining parts or sell them separately.
But I've also learned that Chinese quality isn't bad anymore and the price of my CR-10 is half of the Prusa.
I´ve decided for the future better to buy 2 reliable running CR-10 with a huge build volume instead of one more PRUSA.
The MMU crashed my faith in PRUSA...

Re: Giving up...

I am printing without any issue without MMU but it may be a filament issue in the first place, I ran out of prusa grey PLA filament so I am now using some very low grade ABS orange one (because I won't test with expensive filament) and all of a sudden my problems went away.

PLA was jamming even without MMU (!!!! it didn't before I upgraded but did when I downgraded, weird). ABS is not jamming...at all. I can print without any issue, even complicated stuff is almost perfect.

There is an issue with MMU, don't get me wrong, if something bad is happening and you stop the print, there MUST be a way to retract filament or it will cool down in the extruder and jams will occur 95% of the time. This is the main problem I had, if something goes south, keep in mind to retract the filament asap or you are doomed.

I think MMU may be a good solution BUT it lacks filament sensors, there must be a sensor per filament so the printer knows where the filament is and what filament is loaded when it starts.

I don't know if there is a way to multiplex filament sensors (I think it should be possible, kinda easily but I don't have time now to focus on this) but I pray for Prusa to keep this in mind before they release MK3 MMU, without this it will be a new wave of jamms and unhappy customers.

Re: Giving up...

Jena.marc.c You can send the command M702 C after stopping a print. It will unload the current filament, thus preventing clogging.
You can refer to the supported g-codes in gthub for this g-code.
I also had quite a few problem at the beginning with MMU, now I have almost no problems.
It is quite important for me to print in multi materials, that's why I bought it in the first place.
But I agree that it needed to be better engineered and supported.

Re: Giving up...

Jena.marc.c You can send the command M702 C after stopping a print. It will unload the current filament, thus preventing clogging.
You can refer to the supported g-codes in gthub for this g-code.
I also had quite a few problem at the beginning with MMU, now I have almost no problems.
It is quite important for me to print in multi materials, that's why I bought it in the first place.
But I agree that it needed to be better engineered and supported.

Hello,

Yes sure, I am using Simplify3D so I can even use a dedicated gcode file or snippet or even use the tools to control the extruder. Problem is I have to think about it, which is not always the case. There should be some way to do this automatically. Of course, I realise the printer have no way to know what happened before the emergency reset without some kind of mechanical information and so far, the only tool I know that could do this is filament sensor but you would need one per extruder, which may cause others issues with firmware (but I don't think this is impossible to solve). If you use a single filament, you'll have to extrude each single filament a certain distance until you find the one that was loaded (why not ? After all this is an emergency procedure).

But for the moment, the MMU is desparately lacking this kind of feature, how many times I had to unscrew the Y-splitter just to fix the jamming...?

I will try it again but later, I have to print with all my filaments just to be sure what parameters to use...

Re: Giving up...

I'm so glad to see I'm not alone in this thought. My MK2 was solid and dependable for months, hundreds of prints with only a small number of issues, none of which appear to have been the printer's fault. Ever since I installed the MMU it's been unreliable. When I went to bed last night it was 9 hours into a 15 hour, 12 minute print. Something went south around the 15 hour mark and it didn't print the top 5mm or so. Near as I can tell it just printed air all of a sudden. Couldn't unload the filament this morning, so I'll have to do a hot end tear down tonight, again. I think I've taken this thing apart more times in the last couple months with the MMU than I have the whole time I've owned it by a factor of 20x or so. I'm hopeful that the 2.5 upgrade to the MMU will help with these issues when it ships (whenever it ships). But if not, then I'm seriously going to consider reverting down to just a single material unit again.

SOLVED!!!

As already mentioned a couple of times I‘ve been fighting with the MMU since months and have had countless fail prints so far! The support from PRUSA wasn’t helpful and even hundreds of tips and hints from the forum didn’t bring the solution due to the fact that the MM process isn’t reliable and developed proper!

Let‘s shorten things up... I‘ve disassembled the MMU completely and installed back the original extruder + hotend!!!
And what a surprise... my printer found back to its great reliability and top performance!!!

MY CLOGGING ISSUES AND CONTINUES PROBLEMS WITH MMU ARE SOLVED!!!

Re: Giving up...

Thankfully Im not the only person in this hole. My prusa does other things at the moment. I have had extruders disable themselves during prints, so printer was printing air, couldnt turn them back on. Tried load, unload, settings and move extruders, nothing like the stepper burned out( reset fixed it). I have had numerous resets when mk2 mmu resets itself during a print. Had freezes causing blobs on model. Overall i throw away 1 kg of filament every month due to glitches and errors in the code. WIth hardware I havent had any issues. No jams, nothing. When it wants to print without glitches, it will print nice. 😀 but that happens once in a million.

Re: Giving up...

I heave reassembled the MMU but with original hotend (not the MMU one) and things seem to be almost like MK2S without MMU.

Almoste like without MMU except it may jamm sometimes due to a S3D problem (I think this is S3D) : from times to times, when print begins, it is using the correct extruder for the wipe line but changes extruder when actual print starts...for no obvious reason. I've exported gcode to check, since S3D communication report really states that T1 command was issued, but I can't see it in gcode, only a "T1" trace in command window, so can't say it is S3D or something else (because this window only shows printer echoes, not actual commands sent).

Is someone else experiencing this ?

BTW, my initial post was a bit alarmist, I realised that most of my problems arose when I installed the MMU so I thought it was MMU's fault but it appears it was filament (original prusa grey pla filament, didn't had a single problem with it before this) that was causing problems, I had exact same problems without MMU if using this filament. Dirt or something, can't say.

I still think MMU needs an upgrade, the filament sensoring is mandatory imho, each filament need its sensor to work properly.

Re: Giving up...

Another thing : using PTFE tubes between extruder and spooler seems to help a lot as well, if you can find a box in which you can place your filament and link it to extruder with tube, don't hesitate, it will save you a lot of headaches...

Re: Giving up...

I ordered and received the MMU but luckily I never installed it. I will be putting it on eBay.

Re: Giving up...

I ordered and received the MMU but luckily I never installed it. I will be putting it on eBay.

Well, I am the OP so I think I should reply first : MMU could work great BUT you have to perfectly know your printer before trying to use it. The mistake I made was to install it ASAP, which was a bad move. It is my first printer, figure. I reverted to regular mk2s (still waiting for mk3...doh) and learned it as much as I could, not to mention I also learned to use S3D, which is not the simplest thing to do.

Once I knew the printer well enough and realised that some of my problems with MMU weren't directed related to the upgrade, I tried again and things are MUCH better now. Sure I still have minor issues but it is mainly due to the nature of multi material printing, not directly to the upgrade itself. Every MM printer have same issues when using a single nozzle.

Now don't over estimate the issues ppl are reporting, most of those are due to human mistakes and are misleading you to think the MMU IS the problem. It is not, not directly anyway.

The real issue with MMU is that any potential issue is multplied by every filament change you have to do...and on some prints, there are A LOT...

Re: Giving up...

I think it comes down to will I use it enough to migrate the extra hassle it will cause. If I installed it, and I could just still do single color printing 95% of the time, would I be sorry for adding it? It sounds like yes. I have another printer with dual extruders that I use some. Sometimes two-color but other times PVA. Certainly that dual extruder printer is not without its negatives, but generally even if I use just one extruder, the negatives aren't bad.

It certainly seems like the MMU problems can be worked out, but the question for me is, when will it be 95% reliable with a single filament as the pre-MMU single filament version?

I have two other 3D printers, with a fourth on the way, so I don't think experience is the issue with me, just hassle vs. benefit.

Re: Giving up...

I ordered and received the MMU but luckily I never installed it. I will be putting it on eBay.

Well, I am the OP so I think I should reply first :

Jean-Marc,

I will 2nd your thoughts and thank you for your reassessment after your initial post.

I had been using the MK2S and Slic3r/PrusaControl for 3 months before my MMU arrived. The installation of the MMU and calibration went smoothly. I then printed a one color object with each extruder to verify the tension and first layer quality of each extruder among other things. My main issues were the Z-adjust and filament quality. Once those were sorted out I printed a two color object (Marvin), then three (Geko) then finally four (GearBearing). I know the Prusa manual states, "Print a sample G-code. Gear Bearing is a good start model.", but I thought that to be overly ambitious so I worked up to that.

I print PETG exclusively (primarily MakerGeeks) and am using Slic3r Prusa and PrusaControl with the only adjustments to date being the nozzle and bed temps.
I use DesignSpark Mechanical to create new MM objects and a combination of 3D Builder/DesignSpark/Meshmixer to convert existing objects.

Just confirming your thoughts with a few of my own and thank you again for following through with your thread,

A satisfied MK2S MMU user,
Jerry.

Re: Giving up...

I use DesignSpark Mechanical to create new MM objects and a combination of 3D Builder/DesignSpark/Meshmixer to convert existing objects.

Just confirming your thoughts with a few of my own and thank you again for following through with your thread,

A satisfied MK2S MMU user,
Jerry.

Could you post a couple of your creations? Despite the threads espousing "disaster" there are still a few of us interested in purchasing the MMU.

Re: Giving up...

Happy for anyone that doesn't have issues, but: The problem with the poorly designed multiplexer remains. The strange issues some people have with the custom heatsink remain. The non-responsiveness and total ignorance of user's problems on the part of PR remains. The incompatibility with some types of filaments remains. The bugs in the software and sorely missing firmware features (extruder calibration per channel?) remain. And probably the wrongly assembled hotends also remain.

I agree that many problems are user-made, but for these reasons it's not a market-ready product and they know it.

If they stick at 50€ for the filament sensor upgrade to come, I might consider getting that (potentially it might remove loads of frustration) but only after I'm thoroughly convinced the firmware for that really works.