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gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Antimix
  • Improve the sensors and MMU firmware.
    I noticed that after some retraction / load, the firmware lost the idea of how much filament is out of the MMU. I see it push out around 2cm of filament with the extruder gear on, while the filament is really at 3 cm from the beginning of the MMU-Extruder bowden (too far from the  Extruder). Then it stops the gear, and push other 2cm and activate the gear and wait. And so on until the filament finally reaches the gear and it is loaded. This process take too much time.
    Why it does not push all the filament in one single long movement until it feels the IR sensor triggers ????
    To be checked.

I have a thread in the Hardware section about using a longer PTFE tube and experienced what you are talking about, but in an extreme manner. I opened a GitHub Issue about this for a feature request. I have the ability so I hope to spend some time on it myself and submit a Pull Request.

You mentioned replacing the PTFE tube, are you sure you got it to the same length as the old one? It does the "searching" with my factory tube as well, but it's only once or twice before it trips the IR sensor.

On the marked there is another MMU, that in order to solve some of this loading/unloading issues, decided to take a different path. NEVER unload the filament. The filament is cut and join/melted together during the print on the MMU, so no loading/unloading are required from the extruder, since the filament has a continuous flow into the extruder.

This is how the Palette works and I'm mixed on which method I like better. If you read up on the Palette you will see that it is not without issues as well (you mentioned some). For all it's fussiness, I like the simplicity of the MMU rather than have to deal with hoping that something that is cutting, welding, retracting, etc.. works correctly all the time.

MMU tips and troubleshooting
Posted : 11/06/2019 5:39 pm
Pixel
(@pixel)
Trusted Member
RE: I challenge Prusa to use MMU2S
Posted by: Antimix

TO DO:

  • Change Prusaslicer settings to force a filament CUT after a color change. I noticed that is very difficult to have the "Perfect filament head shape" after a retraction. It depends on the temperature, material, manufacturer. Too many variants. It is never OK. It is better to cut it, to avoid a failure on the next loading.
  • Improve the sensors and MMU firmware.
    I noticed that after some retraction / load, the firmware lost the idea of how much filament is out of the MMU. I see it push out around 2cm of filament with the extruder gear on, while the filament is really at 3 cm from the beginning of the MMU-Extruder bowden (too far from the  Extruder). Then it stops the gear, and push other 2cm and activate the gear and wait. And so on until the filament finally reaches the gear and it is loaded. This process take too much time.
    Why it does not push all the filament in one single long movement until it feels the IR sensor triggers ????
    To be checked.

i dont think the current setup will be able to handle cutting every single filament tip, the blade will be dull in no time as its designed to only out of the stringing and it does this everytime the selector moves from the right to the left side.

I also noticed the slow loading of filament but it only happens once for every filament until you reset the unit, i think the MMU is doing this to self calibrate the bowden tube length, once this is done for all colors it will push the filament very fast until it hits the extruder gears, a filament change doesnt take more than 20 sec for me, then there is the extra time for purging but the change itself is very fast.

Posted : 12/06/2019 6:12 am
CybrSage liked
JLTX
 JLTX
(@jltx)
Reputable Member
RE: I challenge Prusa to use MMU2S
Posted by: Antimix

 We should remember that Prusa products are Open Source and improved by the whole Community.

That's why I bought a Prusa in the first place.  Then I learned the ugly truth.  It is open source, but they do NOT crowdsource anything.  Jospeh is too arrogant for that.  All things must come from him, even if there was a better idea from the community already.  Let's hope a great idea doesn't come from the community because Joseph will design around it.  

Almost nobody from PR participates in this forum, other than posting about SW updates.  Do a search.  They have sold a lot of printers, so the community is large.  But only a small % are tinkerers and innovators.  Good luck collaborating.  I've been trying for 2 years and gave up.  They turned off the feature (on purpose) that allows updating the first post in a thread so that information learned and solutions cannot be updated there for people to find easily.  So you have to read through huge threads hoping to find something.  This just leads to more threads and noise.  They don't allow sticky posts from users, only their own.  They want the appearance of community (I was fooled) but not actually foster it.

I'm glad you are optimistic, but I'm not holding my breath.  I got my MMU2 in Oct.  It has printed one (1!) small print successfully in 9 months!  I just now received the MMU2s upgrade so maybe it will finally print something else.

Posted : 13/06/2019 12:19 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: jltx
Posted by: Antimix

 We should remember that Prusa products are Open Source and improved by the whole Community.

That's why I bought a Prusa in the first place.  Then I learned the ugly truth.  It is open source, but they do NOT crowdsource anything.  Jospeh is too arrogant for that.  All things must come from him, even if there was a better idea from the community already.  Let's hope a great idea doesn't come from the community because Joseph will design around it.  

Looking at the printer and MMU firmware repos there are clearly some non-Prusa contributors and I don't see a mass of "we aren't going to do that" PR rejections. I do know, however, some changes get rejected due to the limited memory the firmware has available.

It's also a misconception that OSS means the original repo has to take your changes. They may have good reasons not to or they may be a bunch of egotistical punks, but it doesn't matter. What OSS gives us is access to the original code so that if you think you have a better solution, you can implement it. You can attempt to merge back or simply run with your own fork (and others can too). This is exactly what happened with Slic3rPE.

Now I will say that looking over their PR history, they don't manage their repo very well (in my professional opinion) as there are no standards for PR details (e.g. description of what the PR's purpose is) or comments on why they closed PRs without merging. Those two items can definitely contribute to the view you have and they don't help people that want to contribute to know what is expected.

The rest of your complaints have nothing to do with the MMU.

Almost nobody from PR participates in this forum, other than posting about SW updates.

For better or worse few vendors actively participate in their user forums. Appreciating it when it does happen is important, but expecting it to happen runs contrary to how the vast majority of companies and forums work.

 They turned off the feature (on purpose) that allows updating the first post in a thread so that information learned and solutions cannot be updated there for people to find easily.

What feature are you talking about? Editing? If so editing old posts is a mixed bag and I've seen it horribly abused on other forums.

As far as people updating first posts with answers, I almost never (I don't think ever actually) saw anyone go back and do that. So if something was lost, it doesn't appear to have been of much value if people weren't doing it regularly.

So you have to read through huge threads hoping to find something.  This just leads to more threads and noise.

There was just as much noise of repetitive stuff before the forum change. One day in the MK3 forum I caught 3 "first layer won't stick" posts all next to each other and all with nearly identical names. The replies to the first were there before the 2nd thread was created and it was answered before the 3rd was created. Each had the same couple of replies with information about cleaning the PEI sheet and fixing the Live Z.

There are certainly things that aren't helping the situation with the new software (e.g. the truly terrible search interface), but many users weren't bothering to try even before the change.

They don't allow sticky posts from users, only their own.

I know of no forum that allow users to sticky posts. That is always a function of the Admins and Mods. If users could sticky their threads the function would lose meaning almost immediately and new non-sticky threads would get pushed to subsequent pages and not seen.

MMU tips and troubleshooting
Posted : 13/06/2019 3:10 pm
CybrSage liked
Nikolai
(@nikolai)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: jltx

I'm glad you are optimistic, but I'm not holding my breath.  I got my MMU2 in Oct.  It has printed one (1!) small print successfully in 9 months!  I just now received the MMU2s upgrade so maybe it will finally print something else.

We are here to help.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 13/06/2019 7:34 pm
Jakub Dolezal
(@jakub-dolezal-2)
Admin
RE: I challenge Prusa to use MMU2S

Hi guys,

multi-material printer is way more complicated design, than the single-material version and requires to be assembled and calibrated properly. I have seen many cases, where the printer didn't work properly, because of some missed instructions. Please make sure you have followed all the parts in the assembly manual and in the Handbook.

Most important is the IR-sensor calibration, the next step is to ensure the filament moves smoothly back and forth. 

Buffer is essential because of the filament retraction and from what we have tested, it is the most reliable solution. There are many great community designs, but not all of them last for a longer period of time. We have tried many, but it didn't meet our requirements. For example, all the printed springs get worn over time and the entire mechanism stops working.

MMU2S was intensively tested and design was changed many times in order to improve the reliability. Final testing took about 2 months with a room full of MMU2S printing 24/7. Some printers required assistance from time to time, but the majority of the prints finished. You can see all the benchmark prints (around 480) in Joe's article: https://blog.prusaprinters.org/original-prusa-i3-mk3s-and-mmu2s-release-sl1-and-powder-coated-sheets-update/

I'm not saying MMU2S is as easy to use as MK3S, but we've done a lot of work and it is a way more reliable and user-friendly machine. In case yours doesn't work, let us know and we will fix it together. It might be that some part is faulty/broken causing the entire system to fail.

 

About Josef not listening, this isn't true at all and it is really strange to read these accusations. All the things we are doing are very much based on your feedback and expectations.

To speak for myself, I'm with my team reading daily the feedback for the assembly manuals and editing them, asking devs to alter the design for easier build. Regarding the forum, I have gathered the most active users to help me going through all the threads and we have dedicated colleagues from the support, who are reading the forum as well.

 

 

 

Assembly manuals

/ Knowledge Base
The guy behind Prusa assembly manuals...

Posted : 14/06/2019 12:25 pm
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

Personally, I think not would be silly if Josef spent his workday reading the forums instead if running the company...he has people to do that for him.  🙂

Posted : 14/06/2019 12:32 pm
vintagepc
(@vintagepc)
RE: I challenge Prusa to use MMU2S
Posted by: CybrSage

Personally, I think not would be silly if Josef spent his workday reading the forums instead if running the company...he has people to do that for him.  🙂

... you mean 20 other Josefs? 😆 

Posted : 14/06/2019 1:27 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

Interesting how the approach is still the classic "stupid user" approach. There's a difference between hearing, and listening. That's the thing. 3 weeks of struggling has me wanting to let the sea have this printer as an artificial coral reef. And I don't really care what Cybersage says about that.

If this thing actually worked as advertised, I'd have no issue... but the original MMU2 gave me success. This thing is a huge fail for me.
Even the brass thing the festo goes into popped out due to the load failures. Bowden tubes are popping out and stuff.

Shane at chat support thought it's funny to mock me - and I have a transcript. Issued an email nonapology to cover his tail. Chat, after at least 2 more hours last night asks me to send a pic, then drops me after I sent the pic of the belt without so much as a word. Then they ask on email "Oh why did you rate my colleage low?" REALLY guys....

Posted : 14/06/2019 7:57 pm
Nikolai
(@nikolai)
Noble Member
RE: I challenge Prusa to use MMU2S

Again perfect example that you can't make it right to everybody.

@Mods and Admins in this forum: Thanks for listening and helping. Most of you guys are doing it in you spare time getting no monetary benefit. That's appreciated!

The community is what it makes this printer a success and great. It's not a superior hardware/the name and not PR alone. It's very easy to blame someone/something for any issue. But fixing it and offering a solution to everybody is what I've seen here many times and that's why I'm still here.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 14/06/2019 9:37 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: nikolai.r

Again perfect example that you can't make it right to everybody.

@Mods and Admins in this forum: Thanks for listening and helping. Most of you guys are doing it in you spare time getting no monetary benefit. That's appreciated!

The community is what it makes this printer a success and great. It's not a superior hardware/the name and not PR alone. It's very easy to blame someone/something for any issue. But fixing it and offering a solution to everybody is what I've seen here many times and that's why I'm still here.

Pretty sure mocking someone in chat is beyond the norm.. unless you think that's acceptable. 15 years in dealing with customer service, escalations, QA, and reporting is where I get this STRANGE idea from. I'm not saying this out of just being unpleasable. There are others who also have not had a single print work in 3 weeks.

I think you would agree, we didn't buy the MMU2 to have it sitting atop the printer looking pretty....
However, if you disagree, in that case, I can't make everyone happy. 😉

This post was modified 3 years ago by Casey
Posted : 15/06/2019 1:00 am
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

They sell cars is kits to, but only in Auto tinkerer would buy one. That person would also understand that he needs to Tinker to just get everything right and running smoothly and properly.

3D printing is the same type of world. Unless you have tens of thousands of dollars spend, expect a lot of tinkering.

Posted : 15/06/2019 1:13 am
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

I knew I could always depend on you to save the day. The printer is sold prebuilt. The MMU2S wasn't, but I would have if it was sold prebuilt.

Maybe you should understand, that there is a certain level of expectation that comes with the Prusa name these days.

One of those expectations is not mocking someone in chat, and summarily dropping you mid-conversation, right after asking for a pic, and the pic having been provided, without a single word.

Pretty clear too on the other issue of the R4 extruder itself MELTING, where the R3 extruder did not do the same, after hundreds of hours of PET printing. Same material. Both were PETG. One melts. The other doesn't. Objective reasonableness.

Seems like you like following me around trying to discredit anyone having trouble though. That's a real shame. I've been trying to follow Prusa's directions 100%, but the problem? Failure to communicate. That's what I really blame. The whole idea I had was, talk to your users.

They DID issue a new survey on the MMU2S, and that is the first step to listening to the customer. I appreciate Prusa Research's willingness to follow this up with that survey, as that is a great and fast way to collect some info about how well things are working - while filtering out fanboy fake surveys, as well as those who didn't really buy the mmu2s.

This post was modified 3 years ago by Casey
Posted : 15/06/2019 1:15 am
Jakub Dolezal
(@jakub-dolezal-2)
Admin
RE: I challenge Prusa to use MMU2S

@cybrsage @casey-b6 Both of you, stop this immediately, stay on topic or leave. This forum is for us all, not your personal battleground. I deleted your previous comments, this is the last warning.

This post was modified 3 years ago by Jakub Dolezal
Assembly manuals

/ Knowledge Base
The guy behind Prusa assembly manuals...

Posted : 19/06/2019 8:09 am
Joe Prints
(@joe-prints)
Estimable Member
RE: I challenge Prusa to use MMU2S

Let's just face it- PR will not sell the MMU2(S) assembled.....because it leaves them the scapegoat of- "you assembled/installed it wrong", or "your settings are wrong".

Anything can be made better
https://www.myminifactory.com/users/Joe%20Prints

Posted : 19/06/2019 3:46 pm
Casey liked
NealC
(@nealc)
Eminent Member
Topic starter answered:
RE: I challenge Prusa to use MMU2S

I'm sure we all got the recent PR Survey regarding the MMU2S. I'm shocked they would state they had a 93% reliability prior to releasing the product. We all know this is completely FAKE/FALSE info. Shame on Prusa, specifically JP.

Neal C
Richmond, VA

Posted : 19/06/2019 3:56 pm
Casey liked
Lichtjaeger
(@lichtjaeger)
Noble Member
RE: I challenge Prusa to use MMU2S

I have a stock MK3S MMU2S and I do have a success rate of about 93%. No issue on my front.

Posted : 19/06/2019 4:02 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: jakub.d

@cybrsage @casey-b6 Both of you, stop this immediately, stay on topic or leave. This forum is for us all, not your personal battleground. I deleted your previous comments, this is the last warning.

I just sent you a private message regarding this. There was never a first warning. I begged you for help, and this is how I am treated.

Posted : 19/06/2019 4:13 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: NealC

I'm sure we all got the recent PR Survey regarding the MMU2S. I'm shocked they would state they had a 93% reliability prior to releasing the product. We all know this is completely FAKE/FALSE info. Shame on Prusa, specifically JP.

I actually don't doubt that claim. What it doesn't include, however, is how much time they spent working out their ideal configuration that allowed it to achieve such results.

I also noticed how the survey was very specific around the assembly rather than "are you getting successful prints". So I expect that they will get the metrics they want from the survey showing that the MMU is great while not really showing the post-assembly frustrations many have.

MMU tips and troubleshooting
Posted : 19/06/2019 4:21 pm
Casey liked
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat
Posted by: NealC

I'm sure we all got the recent PR Survey regarding the MMU2S. I'm shocked they would state they had a 93% reliability prior to releasing the product. We all know this is completely FAKE/FALSE info. Shame on Prusa, specifically JP.

I actually don't doubt that claim. What it doesn't include, however, is how much time they spent working out their ideal configuration that allowed it to achieve such results.

I also noticed how the survey was very specific around the assembly rather than "are you getting successful prints". So I expect that they will get the metrics they want from the survey showing that the MMU is great while not really showing the post-assembly frustrations many have.

Go ahead and set up a Survey Monkey survey and post it in one of the threads here. You can call it anything you like.

Of course the only results you will get are from people who show up on this forum, most of which are people who have problems.

Posted : 19/06/2019 4:27 pm
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