Multi color printing with Prusa's MMU V2 & Duet?

gavatron3000

Here's the first document I wrote for the mmu2. Treat it as a beta at the moment as I'm sure as more people get more hours with it I think there would be improvements.

https://docs.google.com/document/d/13r_6BTYTO-xlD6cQeNwOx4qeCEYYGrxOcHc0mC-tT8Q/edit?usp=drivesdk

NicoLab28

I used the few scripts you had given me, and it's almost starting to work for my MMU.
But my questions are, do you use a cutter, and where?
Do you use ABS filament or just PLA or other.

For my part, I have big problems with the ABS, because it happens to make obstructions, or he puts me back pieces.
The only solution I found is to cut as close to the head as possible.

I saw that some used a cutter at the level of the selector, but it might congest too?

gavatron3000

I don't use the cutter, for me I didn't think it's necessary as the ramming before retraction forms the tip anyways. Abs just works but pla is more difficult. Make sure you use the correct I.D PTFE tube in the Hotend as well. 1.8mm to 1.85mm. capricorn tubing isnt narrow enough either, ive tried.

I almost forgot! I'm adding some modded STL and scad files soon so the filament change will function perfectly as the filament ejection will snag on T4 without a small mod to the selector and main body of the mmu2

NicoLab28

You are in live drive, I looked at your Tipsmoothing.g
10s break anyway, it's just for testing, or is it really necessary?

On my side, it is not too much a problem of diameter of ptfe, I ordered, but of hair, which does not see itself and accumulates until stuffing. I should test your method.

I put transparent tube, and it is obvious.
The worst thing is that it's not regular, it happens from time to time. 15-20 tool change without worries, and boom!
That's why, I put a cutter.

I have the impression, that reliability will be a very hard thing to obtain.

I think I'll test the standard version, what change do you think you'll make? Your files are coming soon?

gavatron3000

look at the link above the info is there, but the files ill add are only for filament changes that affect T4 so 90% of printing is unaffected. if you getting strings you need to tune your ramming settings correctly. this you need to do on your slicer to suit your machine

@nicolab28 said in Multi color printing with Prusa's MMU V2 & Duet?:

You are in live drive, I looked at your Tipsmoothing.g
10s break anyway, it's just for testing, or is it really necessary?

probably not its just a value that definitely works, i was finding that if i retracted too quickly through the extruder it was mashing my tips and causing jams

gavatron3000

adding a cutter to the macros wouldnt be hard youd just need to add a fast selector move across the mmu that chops the tip off if thats what you want but again it'll just build up under the selector anyway. better off just tuning the ramming right

fma

Quality of the tips also depends on the time the filament spents in the nozzle (without extruding). Especially with PLA. I have a simple settings which work great, unless the PLA is sitting in the nozzle for 2 or 3 minutes (in this case, I get oozing).

The solution is to pre-retract the filament at the end of a print.

Scachi

Where do you buy 1.8mmx3mm ptfe tubing from ?
I can't find a source for that. A german shop would be nice but shipping to Germany is good enough

gavatron3000

theres a link in the document above

Scachi

@gavatron3000 said in Multi color printing with Prusa's MMU V2 & Duet?:

theres a link in the document above

Thank you.

gavatron3000

@dc42 regarding triggers, are they meant to go off with immediate effect?

in my document above for loading the MMU2 they work and function as intended but it seems they are delayed until the tool change has completed. is this expected behaviour? id prefer being able to set it off immediately

dc42

The movement system is locked during a tool change, therefore if the trigger macro has any movement commands or other commands that affect motion, those commands will wait until the tool change is complete.

gavatron3000

The triggers in question are like this

M400
M291 "message and wait till ok is pressed"

Should I just remove the m400?

NicoLab28

@gavatron3000 said in Multi color printing with Prusa's MMU V2 & Duet?:

in my document above for loading the MMU2 they work and function as intended but it seems they are delayed until the tool change has completed. is this expected behaviour? id prefer being able to set it off immediately

You're saying that you have the same problem as me, (my post "M581 M582 M291, What am I doing wrong?") To know that the dialog comes at the end of the tool change.
Too late, because the script continued to execute, after the error, which should have been blocking.

gavatron3000

I'm going to try removing the V1 from the M291 as well as the M400 too. But I can't test this until tomorrow

dc42

M400 means wait until all queued motion has completed. So if you send it when a tool change is on progress, it will wait until it has completed.

gavatron3000

I'm hoping that if I remove the m400 and only have a M291 message within the trigger macro that it will pause the tool change if the condition is met.
I'll test shortly when I get a chance

gavatron3000

@dc42 said in Multi color printing with Prusa's MMU V2 & Duet?:

The movement system is locked during a tool change, therefore if the trigger macro has any movement commands or other commands that affect motion, those commands will wait until the tool change is complete.

ok so i removed all the movement commands and M400 from the trigger but to no avail. is it possible allow the triggers in the future to interrupt the tool change and pause when conditions arent met? and then resumed when prompted? that would make this MMU2 work perfectly then

Wyvern

The MMU is interesting, but using Duet components are you not able to use purge blocks and such?

gavatron3000

Purge blocks and the like are generated by the slicer or post processing scripts