https://www.printables.com/model/430419-mmu2s-super-upgrade-msu-selector

Let me know your thoughts about it and I hope you'll all enjoy it!

1. Filament cutter at the extruder -  could some sort of cutter be incorporated into the extruder - that is perhaps activated via a movement fully to the left or right - perhaps at a particular height?   This would I feel solve a lot of the complication with getting a neat tip.  I notice the swapper3d kickstarter includes on of these - but it looks a pretty complicated way to do it. 

2. Motorised rewinders - I know there are plenty of wind up rewinders - but personally I never really got any of the ones I tried to work, and always found the buffers I tried quite awkward to initially load up, plus change filament.   Complicated I know - but could perhaps be based on 4 steppers - controlled from and Arduino connected the Octprint raspberry P1.

- added a 6mm Aluminium Rod inside the Repbox at the top

- designed a printed flap which snap onto the rod

When the filament is unloaded, it is pushed back onto the filament spool. The flaps make sure that the filament does not drop outside of the spool holder and creates a tangle. Additionally, the slack in the filament helps when loading it back to the nozzle, since there is almost no friction.

The filament flap is constructed in OpenSCAD and fully parametrized. Since the spools have varying inner size, you may have to adapt the width. I have added two flaps with 60mm and 62mm inner width for direct printing.

filament-flap

1. the roller unit not staying open while servicing

2. cut filament going all over the bed.

I dont' see any mods for this and before i venture out to design it myself (and address the two issues above) i figured i would ask why it seems like no one has tried it. 

I wanted to check here before trying some custom G-code.

Problem: With my MMU2S, when unloading filament from the extruder the filament needs to be 5C-10C higher than the print temp.

Does this solution make sense? In Filament tab go to Custom G-Code and in End G-Code add in a temp setting? Example "M109 S225;"

I hadn't seen anything else online covering this or examples. I have been going into the sliced model and changing the last layer with custom g-code, but I would like a simpler method.

Thanks for any help!

~Tral

Sorry for the bit bumpy title but I did not know how to express this any better. Let me explain the issue.
I am running this set up off printer and MMU for 1 1/2 years now successfully without any major issues

Recently I am experiencing a significant increase of the following behaviour, which I thought I would have an answer for it already, but now I must admit, the printer sometimes does some irreproducible things at print start.

The the set up respectively the situation:
NO Colour change is sliced, I simply use one spoon of filament e.g. sitting on extruder number 3.
I switch on printer and MMU.
i manually make sure, the MMU knows that the filament is loaded into MMU, by positioning the extruder via the MMU buttons and as well load the filament ( Just MMU, NOT to NOZZLE) using the centre button on the MMU.
I then start the print from the SD.

 printer starts calibration, returns to the home position, and then moves the print head to the right with Y-axias position close to 0 and starts the reverse retract at the print head. NOTE: No Filament has been loadad to the nozzle so far. It still only is in MMUS Bondtech gears and SFINDA LED is red => no Filement in Selector Head.

LDC Dialog the says kind of: "Press button to unload old filament and to load new filament" ( which - see above - in that moment is nonsense).
As a result, the film and then is loaded from you, through Bowden into the print head without the MMU selector has changed its position.

Next is, that some filament is extruded down to the print bed and the LCD presents the question, if this is now the correct filament and asks for pressing okay button so to say.

Pressing okay does make the extruder to spill out another portion of filament and then to move to the home position and start the calibration again - which is super senseless, as it already has happened and the filament does reside in the bondtech gears and the nozzle already.
In the meantime the text appears in the display, that MMU requires attention and then changes to resuming and nothing needs to be done.

After calibration, the printhead again moves to the home position and wants to again load filament ( which it didi before and which now resides in the nozzle) and therefore some awful scratching noises do come both from the printhead and the MMU.
==> minimum issue ( if not more ) is that the printer "forgets" that is was loading the filement right before the second go of calibration.

The gcode does NOT show another "T" command - and as I did power on the printer just before that, the printer or MMU should not think it needs to change filemanet.

The same sometomes happens when reprinting the same model with the same filament.

Any ideas what this is ? Any fixes?

For a while I thought it might happen when re-using 3MF files, but thisoccurs as well sometimes ( irreproducible ) even when creating a fresh 3mf and ensuring to only use ORIGINAL configurations.

help is appreciated ... and .. yes it is the most recent FW, which was valid till some days ago and fw 3.11 DOES NOT TELL the'd have fixed an issue comparable to what i experience.
A few seconds later this stops, and the print starts.

I'm currently running the following mods: MMU2 Reset Button, Prusa MMU2S Rear PTFE M10, Dunil Idler Body (love the easy release tabs), Jfromel Idler (great idler to motor connection!), Vintagepc Selector.

Rather than printing and trying everything, can I get some clues please?