Works well BUT ...  

RE: Works well BUT ...

there are mods that straighten the last 2 cm of the PTFE tube before the MMU. Works well enough for me (not perfect, though).

And yes, going back into a box is probably not an uncommon fate for MMUs ... 

RE: Works well BUT ...

I load my MMU3 very reliably, by pushing from my (Un)original Drybox on top of the enclosure, through the buffer (with the loading fork inserted), and into the MMU.  I use the small tool that rounds the end of the filament, and ensure there is no bend in the last 50 mm.  Other than that, there's no reason for it to fail.

I was very careful to make sure the PTFE were pushed ALL the way into the MMU3 as the directions (and the comments in the instructions) stated.  That's the most likely cause for your difficulties.  You don't have to take anything apart to check that out - look for the step where it says the end of the tube should be visible from inside the MMU.  I remember it did take quite a bit of force to get it all the way in...

RE: Works well BUT ...

I'll see what the phone can see - right now it is in an enclosure so you aren't getting Mk1 eyeball on anything in the MMU. I have been trying through the buffer - I take the reel out and fish for the feeder catching the filament but it is hard to detect the point at which that occurs or how much force - then you get the curly filament sticking up out of the selector mech .... rinse and repeat .... I'll spend some time on it once I get my CoreXY back into service but I would rather not have both printers down

RE:

I assume you don't have the hinged lid for the enclosure - print this and you'll never be sorry you did! https://www.printables.com/model/273426-hinged-lid-for-adding-mmu2s-to-original-prusa-encl (it's also perfect for the MMU3, and helps with moving the printer around or out of the enclosure as well).

The other thing you can do is rotate the MMU3 a bit upwards - detach the bottom 2 clips and pull it up and rotate forward at the same time.  I can get it to rest on the printer frame in that position where I can more easily see the filament exit from the PTFE.

RE: Works well BUT ...

I don't have that - but I will soon, I appreciate that link, was unaware -how does that handle the buffer ?? - I think mine would be more than happy to slide off.

RE: Works well BUT ...

Yeah, there are multiple ways to handle the buffer - mount it to the sides of the enclosure, or inside the enclosure, or in my case I put it on the back:  https://www.printables.com/model/1180632-vertical-buffer-mount-for-rear-of-unoriginal-drybo.   If you do that you really need the loading fork so you can push from inside the drybox, because the buffer cartridges are not easily accessible.

Or make a hanger for the buffer to temporarily hang it on the side of the enclosure if you need to lift the lid.

RE: Works well BUT ...

I use tweezers to guide it, none of the other things have helped with reliable loading, if I am replacing more than one I just open it and feed that way. Its a terrible design

RE: Works well BUT ...

I understand the problems, I went through all of them.    I had the MMU3 in an enclosure.   I mounted the MMU3 Horizontal.   I also aligned the PTFE tubes to go straight into the MMU3 from the back of the enclosure.   Manually straightening the end a little before inserting in the PTFE tube was enough when mounted this way to load reliably.  I want to say easy, but with a buffer or rewinder involved I can't say easy.

A filament sharpener may also help.  A point vs. and angled end has less chance of catching,   

Crossing fingers the INDX  is reliable and available soon.  

RE: Works well BUT ...

I have somewhat learned to deal with it, many other topics that it presents such as filament wasteage - remembering spool numbers and slicing without setting correctly - I have had two horrendous issues where the carriage moved without properly retracting and this really messed things up - in one case the filament broke and jammed and in another it didn't break but completely jammed. 

I don't know that I use it how it was intended, I generally don't mix colours in prints as I am more into 'engineered' parts and not making ornaments - there parts I create are functional, as a result I tend to keep a couple of spools of my 'general' use which is black PETG, a spool of Red, a yellow and a blue again all PETG. 

I have yet to find out what happens if a spool runs out in mid print - there doesn't seem to be a fall back 'join' option - hence my remark about waste - I have obtained a Sunlu filament joiner and once you figure it out it works well so I join a new black spool to the tail of an old one (both black on same side) but it gets a bit messy for other colours especially if I don't want to change colour mid print.

I did add the mod to the case that lets me lift the lid but that has its own challenges as I have height limitations - so now I can take the top off completely i.e. no hinges but it is held in place by its weight anyhow.

RE: Works well BUT ...

Posted by: @the-plastic-shed

 I have yet to find out what happens if a spool runs out in mid print - there doesn't seem to be a fall back 'join' option - hence my remark about waste - I have obtained a Sunlu filament joiner and once you figure it out it works well so I join a new black spool to the tail of an old one (both black on same side) but it gets a bit messy for other colours especially if I don't want to change colour mid print.

When the spool runs out during a print, the Pinda on the MMU3 sees there is no more filament.  The print is paused.  The filament unloaded.  The MMU3 moves over a position and the short piece of filament is "ejected".   from the MMU3.  You have to manually pull the short piece of filament out of the front of the MMU3.  It is about 400mm/16" long.  Then Continue on the screen and the MMU3 goes back to the slot and begins a pre-load process for that slot.   Feed in the new filament into the MMU3 and it loads and continues.  It will ask you to confirm the correct filament after extruding some and then continue the print.    You need to remove the extruded bit before letting it continue on the print.    If it has paused for a while, their may be added delays to re-heat the nozzle. 

Some filament suppliers crimped the end of the filament for winding  assistance.   That little crimp in the end can cause filament to jam during MMU unloading.  Which can lead to print failure trying to clear it all.   On filaments that I know have this problem, I cut the end off before it enters the system.  The crimp on the end is one of the reasons some respool their filaments.  

RE: Works well BUT ...

You have to manually pull the short piece of filament out of the front of the MMU3. It is about 400mm/16" long.

Interesting - how does this look - I don't see how the MMU could eject anything 'forward' without it going to the extruder - what am I missing ? - guess I don't understand the filament detection and path in the MMU3 - time for more research on my part

RE: Works well BUT ...

Posted by: @the-plastic-shed

Interesting - how does this look - I don't see how the MMU could eject anything 'forward' without it going to the extruder - what am I missing ? - guess I don't understand the filament detection and path in the MMU3 - time for more research on my part

 

The MMU3 moves the selector out of position to eject the filament.  If using filament 1, it unloads from the print head.  Filament goes back into the rollers of the MMU3.  Then the MMU selector moves out of position.   The filament remnant is now fed out a few cm/inches out of position 1.  The MMU releases position 1 and pauses. You grab the remnant sticking out of position 1 and pull it out.  When you select Continue the selector positions back to filament 1 and begins the reload.  The MMU3 feeder runs waiting for you to feed the new filament into position 1 for the MMU.  

Quick test, Start a single color short print with about 1  meter/4 ft of filament loaded in the MMU,  When filament runs out you can see the process.  Follow the messages,

RE: Works well BUT ...

Really appreciate the breakdown - I have a spool that's ending so I will set up something unimportant so that I can get a better feel - I've been juggling filament use to maximise consumption of a spool so that I can join it to the next but it sounds like I don't need to be overly concerned (other than for the prints I often leave running overnight)