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gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: CybrSage
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.

How they presented the survey is a common tactic with companies as its is a standard marketing practice to control the tightly focus the questions and then speak generally about the results so it shows what they want.

For example, in this case the questions were pretty tightly focused on the physical assembly and the quality of the kit which I expect that they'll get pretty good marks for. When it's presented (internally or externally), however, it will most likely be framed as "most people are happy with how easy it is to setup". Technically it's not an inaccurate representation, though if asked I would bet the majority of MMU users would define "setup" as including the process up to getting a successful print rather than simply to the point of powering it on and uploading the firmware.

And you are absolutely correct that if we posted our own survey that the results would be equally biased. Both in the more limited audience as well as our own biases that would show up in the wording and type of questions.

I didn't mean my previous comment to be critical of Prusa specifically, its more general about how such surveys are done and used. I was mainly just predicting the results compared to what we have seen.

MMU tips and troubleshooting
Napsal : 19/06/2019 5:04 pm
CybrSage se líbí
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

Hey gnat, my $0.02 on surveys:

I'm employed in an industry that uses surveys heavily for our clients, as a third party for some fairly large companies. While survey results can be skewed by how questions are asked, a common industry practice is to evaluate the neutrality of the questions in a board/red-hat review setting.

From what I saw in Prusa's survey, my opinion, informed by experience, is that they appear to intend on using their surveys more as a point of comparison/fact-finding. I haven't seen them make a big deal of a 'likelihood to recommend' KPI just yet.
Of course, it's not easy to understand/judge intent without getting it straight from the company, not trying to speak for Prusa here.

My feeling is they aren't really trying to skew it intentionally, but it's apparent that surveys isn't the #1 skill/job (like mine is). Overall, I liked what I saw in their survey, in terms of what questions were asked.

Usually if we're competing/marketing that performance, a company would use some method like a Net Promoter Score (spectrum scoring i.e. top 2/10 - bottom 6/10 = NPS), CSAT (top 2 of 10 percent), CS Index (discounts the neutral raters) which more accurately reflects a sentiment.

This post was modified před 5 years by Casey
Napsal : 19/06/2019 5:15 pm
CybrSage se líbí
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O

Overall, I liked what I saw in their survey, in terms of what questions were asked.

Oh I agree actually. For what it covered it was pretty well done. Just saying that there is room for more (probably useful for making it a better product overall) questions about how we are finding using it.

MMU tips and troubleshooting
Napsal : 19/06/2019 5:33 pm
CybrSage a Casey se líbí
Dave
 Dave
(@dave-11)
Eminent Member
RE: I challenge Prusa to use MMU2S
Posted by: jakub.d

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.

Jacub, I'm new to Prusa, it's my second machine. I have a Lulzbot Mini 2. Quick background, I recently retired after a career as a hardware, software design engineer, support engineer, rising up through management to end my career as COO of a small tech company in Silicon Valley.

I have been most impressed with PR, Joseph, and the work of his company. While a very skilled engineer that could assemble the MK3 and MMU2S with incomplete instructions, I have to say that the assembly manual for the MK3 is among the best I've ever seen. The parts organization in the kit is very well thought through and designed to make assembly straightforward and easy.

Quality -- so far, I am much more impressed with the design, materials, and engineering skill put in to the design. I wish I had bought the MK3 first, not the Mini 2, kit is half the price, and I can see it's going to be a better, more accurate printer (I'm just assembling it now, using a spare hour or two a day, so it's not coming together as fast as I'd like!)

One example: The rod bearings. Very high quality, linear ball-bearing sleeves.  The Mini 2 uses plastic oil-impregnated bearings, no rolling component, and as a consequence I have a vibration in my table that shows up at a particular speed and puts ringing in the print, no matter what I do to clean and lube the Y-axis rods. This will not happen, ever, with the kind of bearings on the MK3.

I could go on and on, but I'll stop now. Just wanted you to know that, from the perspective of someone who has seen all of this sort of thing from the other (in) side, you guys are doing a top-notch job, have designed a really solid, quality product. I have no doubt that when I get to the MMU2S in a week or two, I'll have issues, but I'd probably faint if I didn't with anything as complex assembled from a kit.

Anything like that, with dozens of parts, will take adjustment, tuning, loosening and tightening bolts, slightly changing alignment of "stuff", working out friction issues, etc. THAT'S WHAT YOU GUYS DO WHEN YOU TEST IT.

It's a kit. Most of the work is adjusting it, not putting it together.

Keep up the great work. I'm very impressed!

Napsal : 20/06/2019 3:21 pm
Nikolai, Antimix a CybrSage se líbí
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

Truth be told, I do think there's something to the "Prusa Research doesn't listen" idea, based on my recent experiences/communication with them.

They do some stuff well, but other stuff, horribly wrong. Honestly it left me wishing I never became interested in owning a genuine Prusa printer, for a few reasons.

I'm glad it works well for you. Maybe you won't experience what I have experienced.

Napsal : 20/06/2019 3:25 pm
Dave
 Dave
(@dave-11)
Eminent Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O
Posted by: nikolai.r

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.

With your experience in customer service, you surely understand that something like "mocking" is subjective, and too a degree in the eye of the beholder. I'm not saying it didn't happen, but rather that it's not a simple objective fact, and that discussing it is likely to result in a "which ice cream flavor is the best" sort of pointless argument.

I understand you're miffed, but I'd suggest dropping it. You're wasting your time trying to persuade others of the scurrilousness of PR over something as trivial as this.

Napsal : 20/06/2019 3:30 pm
CybrSage se líbí
Dave
 Dave
(@dave-11)
Eminent 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 don't know that. How do you?

While a surprising success rate in light of all the problems posted here, I don't automatically discredit it. After all, the engineer(s) who designed it, assembling and tested over dozens of prototype builds, and techs assisting them, are likely very good now at assembling an MMU2S that works with just some final adjustments.

Napsal : 20/06/2019 3:38 pm
CybrSage se líbí
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Dave

I understand you're miffed, but I'd suggest dropping it. You're wasting your time trying to persuade others of the scurrilousness of PR over something as trivial as this.

I don't think what he has described is trivial, especially to him. It does seem contrary to all other reports about Support (even when they couldn't help fix the issue) though which is why I think may of us doubt the veracity of his claims. It could have happened though and that is a problem Prusa needs to take seriously and investigate. It could also be (and I've been there) that his frustration is simply making him take things more personally than something was intended.

For me personally I've had 3 interactions with Support (damaged PEI sheet on arrival, a "where the hell is my MMU" query, and a missing IR sensor cable for the MMU/MK3S upgrade) and they've been professional and taken care of what was needed quickly.

I don't, however, go to them about things like the issues I've had getting the MMU to work nicely. Maybe I'm not giving them the benefit of the doubt, but my gut feeling is that the community is more knowledgeable. That, I'm sure, is mostly made up of bias from my own time doing customer support as well as experiences with support groups as a customer. While there are excellent reps out there that can and do go above and beyond, the majority get lost quickly when you have more esoteric questions (like the optimal allowable curvature for the PTFE tube to not cause undue friction).

Additionally having to dedicate potentially multiple hours to a live chat session is non-ideal and the forum format of asking questions and trying answers when I have time works better for me.

MMU tips and troubleshooting
Napsal : 20/06/2019 3:55 pm
Casey se líbí
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S

Support has always been amazing for me as well, but just like you I go to the forums when I have some tricky issue. Often times someone else already ran into it and fixed it.

And I go to the forms for the same reasons.  🙂

Napsal : 20/06/2019 4:01 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat
Posted by: Dave

I understand you're miffed, but I'd suggest dropping it. You're wasting your time trying to persuade others of the scurrilousness of PR over something as trivial as this.

I don't think what he has described is trivial, especially to him.

Hi gnat. Yeah, I have the transcripts saved, so there's that... If you want a copy, let me know. I was speaking more about how this thread has went than anything.

Mocking isn't actually that subjective in the QA world. There are easily recognizable patterns there.
We actually have this AI program, which for email and chat, it does some really cool things. It does sentiment analysis based on freeform words (Clarabridge), and another plugin which looks for service drainer phrases based on customer responses and surveys. It's a bit of an interesting adaptive piece of software, and it has helped me bring up some survey scores for clients who had a NPS of -50 to a +30, on an escalation queue. (NPS is a scale of -100 to +100, based on likelihood to recommend). 

There was actually a factory tour vid of Prusa's factory, and there was a wall of funny/stupid customer comments up there.  In my workplace, that would not be permitted, because of the possibility of it getting back around. That told me that perhaps, it is considered acceptable to them internally.

Yet, we do need to consider in fairness to Prusa.... That's not a big pro-level customer service/customer relations corporation, like the company I work for.
It's not their number one focus. They don't have other clients who they have to be responsible to, or else have to pay contract penalties. I understand where it comes from. Is it right? Well.... That's a matter of opinion, and opinion alone.

Napsal : 20/06/2019 4:21 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

Will say, as for MMU2S performance, which is what I was talking about from the start..... Hopefully shipping it overseas to them will solve the problems, along with the melting hot fins on the bottom of the extruder.

I have doubts, but I'll follow their directions and give them every chance - even though I wasn't afforded the same.

Napsal : 20/06/2019 4:28 pm
CybrSage
(@cybrsage)
Honorable Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O

Will say, as for MMU2S performance, which is what I was talking about from the start..... Hopefully shipping it overseas to them will solve the problems, along with the melting hot fins on the bottom of the extruder.

I have doubts, but I'll follow their directions and give them every chance - even though I wasn't afforded the same.

Out of curiosity, what chances did they not afford you?

Napsal : 26/06/2019 2:48 am
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

The printer will arrive at Prusa Research tomorrow. Fingers are crossed.

Napsal : 26/06/2019 2:52 am
CybrSage se líbí
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S

It's in their hands now/delivered. I'll await Prusa's advice. If I see anything special they do to correct the filament load issue or hotfin melting issue, or anything particular that I missed as part of those two issues, I'll share it here.

If they get reliability exceeding 70% (trying to be generous) out of their own MMU2S machines in the perfect factory/lab setting, there's no reason why I should expect any different out of this one when they're done with it.

The lingering concern I have, unless they've already set up a new revision/beta/rc of the part, is the hot fins melting on the R4 design. Mine was melted pretty good. Best not put the cart before the horse.

As for Mike's question, Jakub made it clear that this isn't our battleground. That is my only answer to you.

Napsal : 26/06/2019 2:23 pm
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O

If they get reliability exceeding 70% (trying to be generous) out of their own MMU2S machines in the perfect factory/lab setting, there's no reason why I should expect any different out of this one when they're done with it.

This is a flawed expectation and you need to adjust it to reality or you are going to be right back here complaining about the MMU and Prusa when it isn't really their fault. What you should expect from this exercise is the knowledge that the printer is indeed assembled correctly (see shipping comments below) and that it can work when you find the right setup for your environment.

The first issue is international shipping. Things will be jostled around and may come out of calibration. We know, for example, that the IR sensor can be a PITA to get working right. It's quite possible that they could get it dialed in perfectly, but then it moves a hair during shipping and now you've got problems. Maybe the printer moves a bit and pinches or kinks a PTFE tube. Etc...

Secondly it is no surprise at this point that what works for one person does not work for another. So unless you can set it up exactly like they did, then expecting the same results out of the box is just silly. You will still have to find the magic configuration for your environment that feeds the filament to the MMU just the way that it wants it to give you successful prints.

I just don't want you to have unrealistic expectations that lead to you coming back here and complaining about the MMU and Prusa for things that are either not their fault (shipping) or that are known things that have to be worked through (setting up your specific configuration). There are 3 things I would expect from this exercise and anything more (I think) is just asking for disappointment:

  1. That the printer and MMU are assembled correctly (see shipping comments).
  2. That it is known to work when you find the right configuration for your environment.
  3. Sans shipping related issues, single filament printing should work.

I don't like that I've sunk an extra $200 (2020 extrusion frame and bits, PTFE tubes, festos, and printing various spool holders and mods) to get a $300 module working nicely, but I did and it is. Since getting the kinks worked out, my limited multi-color prints have yielded a better than 99% success rate for tool changes. It wasn't easy to get there and it was extremely frustrating at times, but it is possible.

MMU tips and troubleshooting
Napsal : 26/06/2019 3:08 pm
stoofer
(@stoofer)
Estimable Member
RE: I challenge Prusa to use MMU2S

I was at 0% when I filled out the survey as I was still working through my problems.

I'm now at just two failed tool changes since I addressed my problems ~100 hours of printing multicoloured parts ago. My main issue now is that the purge tower likes to peel itself off the bed as the print goes on. I'd like a fully solid bottom layer on the tower, ideally.

I can believe 93%, once a machine is "working" with an experienced builder/troubleshooter who understands the machine. It's quite a hard machine to actually understand until you see how it's supposed to work, which makes troubleshooting difficult.

 

Napsal : 26/06/2019 4:16 pm
CybrSage se líbí
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: stuart.b4

My main issue now is that the purge tower likes to peel itself off the bed as the print goes on. I'd like a fully solid bottom layer on the tower, ideally.

Hmmm.. I have the opposite issue and I think having attempted all those Benchies (8 maybe) has damaged the PEI at the 4 corners of it's tower.

MMU tips and troubleshooting
Napsal : 26/06/2019 4:30 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: gnat
Posted by: Casey/NZ2O

If they get reliability exceeding 70% (trying to be generous) out of their own MMU2S machines in the perfect factory/lab setting, there's no reason why I should expect any different out of this one when they're done with it.

This is a flawed expectation and you need to adjust it to reality or you are going to be right back here complaining about the MMU and Prusa when it isn't really their fault. What you should expect from this exercise is the knowledge that the printer is indeed assembled correctly (see shipping comments below) and that it can work when you find the right setup for your environment.

The first issue is international shipping. Things will be jostled around and may come out of calibration. We know, for example, that the IR sensor can be a PITA to get working right. It's quite possible that they could get it dialed in perfectly, but then it moves a hair during shipping and now you've got problems. Maybe the printer moves a bit and pinches or kinks a PTFE tube. Etc...

Secondly it is no surprise at this point that what works for one person does not work for another. So unless you can set it up exactly like they did, then expecting the same results out of the box is just silly. You will still have to find the magic configuration for your environment that feeds the filament to the MMU just the way that it wants it to give you successful prints.

I just don't want you to have unrealistic expectations that lead to you coming back here and complaining about the MMU and Prusa for things that are either not their fault (shipping) or that are known things that have to be worked through (setting up your specific configuration). There are 3 things I would expect from this exercise and anything more (I think) is just asking for disappointment:

  1. That the printer and MMU are assembled correctly (see shipping comments).
  2. That it is known to work when you find the right configuration for your environment.
  3. Sans shipping related issues, single filament printing should work.

I don't like that I've sunk an extra $200 (2020 extrusion frame and bits, PTFE tubes, festos, and printing various spool holders and mods) to get a $300 module working nicely, but I did and it is. Since getting the kinks worked out, my limited multi-color prints have yielded a better than 99% success rate for tool changes. It wasn't easy to get there and it was extremely frustrating at times, but it is possible.

Gnat,
I would appreciate it if you didn't attempt to make my statement out to be more than it actually is meant to cover, in your attempt to make everything I say somehow "wrong/flawed."

My statement is meant to affirm that Prusa is trying, that I am trying to trust their expertise, advice, and instructions.

  1. I'm not new to 3D printing, kit builds, or self-builds (albeit less features than this smarty printer).
  2. It isn't unreasonable to expect an extruder to be designed with materials/physical design enough to not have it melt and sag into your prints. I didn't design that, and here you are trying to pin this junk on me specifically.
  3. I am more than capable of getting consistent readings on the IR sensor through the calibration instructions.
  4. There are perhaps thousands of happy MK3S/MMU2S users out there. I've not heard from them, but  I trust that they exist, even though I've seen problem after problem, but that doesn't mean they're not out there, and it also doesn't mean they converted to ALU extrusions for the printer frame - nor is that necessary. Nor is it necessary to become as patronizing and condescending as you have.

My expectation is stock performance that PRUSA expects/believes should be there, will mirror actual stock performance of the machine.

I am SO sorry if you don't trust the above with Prusa, or their ability to safely ship these printers, and I'm sorry if your printer encountered a shipping issue... I can only speak for the person who shipped it to Prusa, and I am quite confident in their packaging job, since I watched them do it. Enough packing material to have quite the 'carbon footprint.'

That's not unreasonable, and it means that EVEN IF my beard doesn't look as well kept as Jo Prusa himself, and is a millimeter longer, even though I am now getting gray whiskers,  it should not be far off from where it should be, on how it is built, other than very minor adjusting after shipping (i.e. buffer friction, or spool holders, vs distance method)... 

To be clear on 'environment,' I have never had a friction issue in the ORIGINAL MMU2, which I had success on, and that one, as I understand it, is said to be less reliable - and that the MMU2S was a lot better.
Further, the room this machine is in, is normally at a constant 73F/22.7C ambient temperature, because it is shared with 3 28 core XEON servers, an Alcatel SAR, 4 UPS racks, and some other switching equipment. As you might imagine, noise isn't a problem in this setting. The room itself is noisy, and the raised tile floor is great at producing unsettling echoes. (LOL)

There is nothing as special with my setup, as you have done to your printer. It is my opinion that once you go to a completely different frame, it's no longer considered an Original Prusa i3 MK3(s)/MMU2(s). If I had made such a drastic modification, I would not have bothered Prusa Support with this, because the printer would be of my own doing/design...... 

If you expect every single shipped printer to be destroyed in shipping, then maybe the better point is to reconsider who does the packaging, but I have never shipped a Prusa printer back and forth. We will have to wait and see the results.

I firmly believe Prusa's pre-flight checks/calibration is still needed any time you move the printer from place to place, even if it's across the room. Maybe I'm wrong about that.

Now, if you will excuse me, I will get back to TRYING to be optimistic and trust the job that the Prusa Research technicians/engineers are capable of, and try to not bother them/interfere with them fixing that printer up. 🙂 

Napsal : 26/06/2019 5:16 pm
Casey
(@casey-2)
Estimable Member
RE: I challenge Prusa to use MMU2S
Posted by: stuart.b4

I was at 0% when I filled out the survey as I was still working through my problems.

I'm now at just two failed tool changes since I addressed my problems ~100 hours of printing multicoloured parts ago. My main issue now is that the purge tower likes to peel itself off the bed as the print goes on. I'd like a fully solid bottom layer on the tower, ideally.

I can believe 93%, once a machine is "working" with an experienced builder/troubleshooter who understands the machine. It's quite a hard machine to actually understand until you see how it's supposed to work, which makes troubleshooting difficult.

 

I think you hit on a point I've made before....
I'm an experienced builder, multiple printers/brands, so I'm not the dumb person that I'm being made out to be.

HOWEVER, an original Prusa is so far quite different from any of the clones, Ultimakers, Lulzbots, Printrbots, etc. It's important to have someone who is experienced with THAT machine, to look at it, when it gets past a certain point....

Even though you might have done deltas, CoreXY systems, dual extrusion with a lot of success, or maybe built some Chinese clone kit with an i3 name or an i3 like design on say, a Creality.... it isn't a Prusa i3 MK3s/MMU2s - far from it on so many levels. Each machine is certainly unique in different ways.

I do not claim to be an expert on the Prusa i3 MMU2s.
I know we have a lot of self-proclaimed experts in here, but I come more near trusting Prusa's people and their ability to make their machine work as they designed it, because they designed it, and they know its mechanics better than anyone on this forum.
That's what I base my hopes on. Let's just hope that isn't misplaced.

Napsal : 26/06/2019 5:26 pm
CybrSage se líbí
gnat
 gnat
(@gnat)
Noble Member
RE: I challenge Prusa to use MMU2S
Posted by: Casey/NZ2O
Posted by: gnat
Posted by: Casey/NZ2O

If they get reliability exceeding 70% (trying to be generous) out of their own MMU2S machines in the perfect factory/lab setting, there's no reason why I should expect any different out of this one when they're done with it.

This is a flawed expectation and you need to adjust it to reality or you are going to be right back here complaining about the MMU and Prusa when it isn't really their fault. What you should expect from this exercise is the knowledge that the printer is indeed assembled correctly (see shipping comments below) and that it can work when you find the right setup for your environment.

The first issue is international shipping. Things will be jostled around and may come out of calibration. We know, for example, that the IR sensor can be a PITA to get working right. It's quite possible that they could get it dialed in perfectly, but then it moves a hair during shipping and now you've got problems. Maybe the printer moves a bit and pinches or kinks a PTFE tube. Etc...

Secondly it is no surprise at this point that what works for one person does not work for another. So unless you can set it up exactly like they did, then expecting the same results out of the box is just silly. You will still have to find the magic configuration for your environment that feeds the filament to the MMU just the way that it wants it to give you successful prints.

I just don't want you to have unrealistic expectations that lead to you coming back here and complaining about the MMU and Prusa for things that are either not their fault (shipping) or that are known things that have to be worked through (setting up your specific configuration). There are 3 things I would expect from this exercise and anything more (I think) is just asking for disappointment:

  1. That the printer and MMU are assembled correctly (see shipping comments).
  2. That it is known to work when you find the right configuration for your environment.
  3. Sans shipping related issues, single filament printing should work.

I don't like that I've sunk an extra $200 (2020 extrusion frame and bits, PTFE tubes, festos, and printing various spool holders and mods) to get a $300 module working nicely, but I did and it is. Since getting the kinks worked out, my limited multi-color prints have yielded a better than 99% success rate for tool changes. It wasn't easy to get there and it was extremely frustrating at times, but it is possible.

Gnat,
I would appreciate it if you didn't attempt to make my statement out to be more than it actually is meant to cover, in your attempt to make everything I say somehow "wrong/flawed."

I didn't make your statement out to be anything more than the words you actually wrote. You explicitly stated that if they get it working that you expect it to work for you when you get it back. My response is simply trying set reasonable expectations, but based on this response it is clear you would prefer to be angry. After this response I'll leave you to it as I have better things to do than try to help someone that doesn't want it.

My statement is meant to affirm that Prusa is trying, that I am trying to trust their expertise, advice, and instructions.

I never stated or implied otherwise. I only responded to your flawed expectation about how the machine will perform when you get it back.

  1. It isn't unreasonable to expect an extruder to be designed with materials/physical design enough to not have it melt and sag into your prints. I didn't design that, and here you are trying to pin this junk on me specifically.

Talk about putting words in someone's mouth. I did not mention anything about that issue at all. 

I explicitly didn't mention it because it has nothing to do with the MMU. There is a recent topic in the MK3S forum specifically about it (where I have posted as it has happened to me as well). There is no need to pollute MMU issues with issues not related to it.

  1. I am more than capable of getting consistent readings on the IR sensor through the calibration instructions.

As does almost everyone else, until it starts actually printing and then the IR sensor has a tendency to get flaky. Many of us have found that to be the biggest source of our troubles.

  1. There are perhaps thousands of happy MK3S/MMU2S users out there. I've not heard from them, but  I trust that they exist, even though I've seen problem after problem, but that doesn't mean they're not out there

There have been a few that have posted in this thread. There are more in other threads throughout the forum. Why you can not see us or understand what we say is beyond me.

  1. , and it also doesn't mean they converted to ALU extrusions for the printer frame - nor is that necessary. Nor is it necessary to become as patronizing and condescending as you have.

Not sure if this is a reference to what you highlighted in my response, but I haven't seen anyone convert their printer just to get the MMU to work. My reference is about the frame I built to hold the spools above the printer as I do not have space for them to sit on the desk behind it.

My expectation is stock performance that PRUSA expects/believes should be there, will mirror actual stock performance of the machine.

Which it will. That is being shown by other members of this forum. You really need to get past your anger and read what other people are saying across the forum. Yes we had challenges. Yes things didn't work the first time. With patience, persistence, and listening to other users, however, we found paths to get the system configured so it works for us.

We know that the IR sensor is finicky to get right, but once that is sorted it is solid. We also know that the MMU does not like resistance in the movement of the filament. Sorting out those two things has so far sorted out the majority of peoples issues. Unfortunately the later is challenging as it is very setup specific.

I am SO sorry if you don't trust the above with Prusa, or their ability to safely ship these printers, and I'm sorry if your printer encountered a shipping issue... I can only speak for the person who shipped it to Prusa, and I am quite confident in their packaging job, since I watched them do it. Enough packing material to have quite the 'carbon footprint.'

It has nothing to do with Prusa. It is the reality of shipping complex goods across the world. I'm glad you've never had problems with shipping, but stuff simply happens and it doesn't even have to be as bad as visible damage to the outside. 

To be clear on 'environment,' I have never had a friction issue in the ORIGINAL MMU2, which I had success on, and that one, as I understand it, is said to be less reliable - and that the MMU2S was a lot better.

The original setup didn't have friction issues in it's out of the box form because it didn't have the extra PTFE tubes or buffer to contend with. In fact otherwise other than a different PTFE between the MMU and extruder if your MMU was old enough there isn't a difference between the MMU2 and MMU2S. 

There is nothing as special with my setup, as you have done to your printer. It is my opinion that once you go to a completely different frame, it's no longer considered an Original Prusa i3 MK3(s)/MMU2(s). If I had made such a drastic modification, I would not have bothered Prusa Support with this, because the printer would be of my own doing/design...... 

Now I know you were referring to my comment above and I also know that you clearly don't bother to read other threads in this forum where we hash out the issues that we have run into.

Let me be perfectly clear the only modifications to Prusa supplied hardware and software I have made are:

  1. I use "Unload speed at start" set to 120mm/s
  2. I have changed out the MMU -> extruder, buffer -> MMU, and input to the buffer PTFE tubes with Capricorn XS tubes to remove kinks and friction.
  3. I added the festo mod to the input side of the MMU to remove the compression from the ends of the PTFE and also to make getting at the filament easier.
  4. I added the festo mod to the input and output sides of the buffer to again relieve pressure and move all filaments to the same side of the buffer.
  5. I have never used the supplied spool holders/trays as I never had room for them.

 

None of those are "drastic modifications".

 

Anyway, as I said, I'm done trying to help someone that doesn't appear to actually want help and would rather attack people. I do hope you get your issues resolved and get the printer working, but I'm not going to bother following up anymore.

MMU tips and troubleshooting
Napsal : 26/06/2019 7:02 pm
Stránka 3 / 10
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