Thanks to the Forums  

RE: Thanks to the Forums

We need more posts like this.

I have my MMU a few weeks now and it is doing fine. Most problems I had were because of this I did with getting my spools and buffer in the right place and not having enough room to keep the ptfe tubes short and straight.

I also did watch plenty of videos and read these forums. From what I had seen it all comes down to being very precise building it and setting it up.

It isn't as bulletproof as the MK3 alone, but with some time invested it sure does work.

I haven't regretted buying it.

RE: Thanks to the Forums

My MMU is scheduled for delivery on Monday. Based on this forum and others, you get the impression that the MMU is completely buggy and unusable. So far, I attribute this to the following:

1. People who bought an assembled i3 and didn’t appreciate the effort required for assembly. 
2. People who were sloppy with assembly of the MMU. (I made one critical mistake in my i3 assembly that I had to correct about a month later). 
3. Unrealistic expectations. I have had to learn and experiment with the base i3 and I expect to adjust for the MMU.

So far, I’m most impressed with the YouTube video called MMU2S Theory of Operation. 

RE: Thanks to the Forums

One more: complaints about older versions of the MMU that were addressed in the MMU2S. 

RE: Thanks to the Forums

@gglockner

That is true.  Needs some polishing but a good product.  I built one and am about to order one for myself.  

RE: Thanks to the Forums

The number of people who are successful with it are far outnumbered by those who are not.  The firmware is buggy as hell and hence why they are doing a complete rewrite at the moment.  Simply stopping your print at the right time can result in the printer and the mmu getting out of sync.

It certainly doesn't work well for most people out of the box without a number of mods.

It depends completely on the day and how the printer is feeling at the time if it'll work or not.  I've had days where it can do 500+ tool changes without issue.   And others where it won't.  So having done all the other optimizations, I JUST now put on 3mm ID tubes in an effort to reduce friction I just started a 5 color print as a real test.  It got through 2 color changes before I had to intervene.  This is a 1d6h print as it is so I'm not holding out a lot of hope.  I'm about done with the darned thing.

RE: Thanks to the Forums

@gglockner

That theory of operation vid is excellent I admit.  It definitely gives you insight into the random errors you might probably see when trying to get the thing up and running.

RE: Thanks to the Forums

So after the first intervention it SEEMS to be ok for now.

RE: Thanks to the Forums

@ssill2

Where did you get the file for the small clip on your filament boxes? It may be more of a PTFE clip or holder.  

RE: Thanks to the Forums

@cwbullet

I made it n blender.  It’s printed in tpu

RE: Thanks to the Forums

so as it turns out 3mm tubes seemed to make the problem worse.   I ended up killing the print last night.  I couldn't get one of the filaments to load again once it made me intervene.  I think 3mm gives the 1.75mm filament too much play inside the tubes.  I'm probably going to swap back to the 2mm ID tubes and just try to get as many bends out of the path.

RE: Thanks to the Forums

Did you use 3 mm PTFE tubes only between the MMU and the spools or also between the MMU and the extruder.

I can imagine that the wider tubes don't hold the filament when the idler is turning and that the filament gets pushed out between the idler and the pulleys to the back. Resulting in the pulleys not being able to grab and feed to filament to the extruder.

I'm now using auto rewind spool holders (my own remix) and short PTFE tubes with no sharp bends.

Only one load problem yesterday. But that was because I loaded to wrong filament profile in PS and the tips got to big because of the lower temp (205 instead of the 220 I tested and worked fine)

RE: Thanks to the Forums

@baklin

I replaced them all.  But I'm going to back it out today and see. 

RE: Thanks to the Forums

Alright, I took the printer out of the enclosure and put shorter 2mm ID tubes back in place.  I have a test print with some new filament going.   After that I'll try a 5 material print again.

RE: Thanks to the Forums

*knock on wood*  it seems to be working....

RE: Thanks to the Forums

ok, so of course it failed.  it was going along fine for hours and then when it tried to retract the filament one time, it couldn't because of blob.  Thus I intervened, pulled the filament, cut the tip, loaded the filament, resumed.  The extruder moved back to the purge tower, loaded the filament to the extruder and then shot a big wad of filament in place before it started to move.  I've seen this before.  Of course the filament hardened into a big blob, and cause crashed detection numerous times when trying to move about on the purge tower to to get going again.  Thus the the print was hosed and I had to stop the print job.  These are precisely the kind of issues I think are why they are rewriting the firmware.  While the shorter tubes seem to decrease the number of interventions,  When there are issues I have seen the thing totally space out on several occasions ending the print because no amount of button pushes etc will get the thing back in a good state.

They are desperately in need of a new firmware and a redesigned MMU3.  This is why I'm looking at chucking the MMU and converting this printer back to an MK3S+ and getting a third printer that has multiple extruders.

RE: Thanks to the Forums

@ssill2

When you say "because of blob", do you mean a blob at the nozzle or a tip issue at the end of the filament?

RE: Thanks to the Forums

hmm, trying to respond and it won't let me.

RE: Thanks to the Forums

Trying to respond with actual answer but I keep getting a wordfence error.

RE: Thanks to the Forums

So in this case, the blob was not on the tip of the filament.
 
This was the case where on loading the filament you heard an odd noise from the extruder and it in fact squirted a bunch of filament in the same spot, right on top of the purge tower.
I saw this once before at the beginning of a print when the extruder moves to the bottom left and and parks right above the plate, before its priming extrusion.
In this case, the IR sensor was not fully calibrated and the mmu kept sending filament because the IR sensor hadn't triggered and told it was there.
The result was a large blob created because the extruder kept extruding but it was not moving.

This had been print for hours and hours and thus when I resolved the problem and told it to resume, it went back to its position on the purge tower and loaded the filament and prior starting to move it extruded a bunch of filament in place.