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Are there G-codes for *specific* MMU2S operations?  

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Chiral Symmetry
(@chiral-symmetry)
Active Member
Are there G-codes for *specific* MMU2S operations?

I'm wondering if there are G-codes to tell the MMU2S to do very specific actions.

Examples:
(1) Move selector to position (1-6) but no other actions.  (No loading/unloading, etc.)
(2) Move idler barrel to a specific filament (1-5).  (But no other actions.)
(3) Have MMU2S gear-teeth feed forwards/backwards a distance X.  (But no other actions.)

Why I want to do this:

I'm having some trouble with tip strings that get trapped between the selector and the front PTFE holder.  If the strings were not trapped, they would just poke forwards into the air, and then get cut-off by the blade when the selector moves back.  (btw, I tweaked the design of the front PTFE holder, so that strings that poke out *are* cut off by the blade.  So strings are cut, but hairs are sometimes too fine/flexible to be cut.)  So if I could just move the selector out of the way, and then push the filament forward enough (longer than the tip string), the tip string would free itself and (mostly) poke forwards into the open.  Then the filament could be pulled back to it's original position with the tip-string ready to be cut.

What I have tried, but isn't what I want:

I've seen the G-codes for the MMU that select a filament (T0 to T4).  But that does too many things; they load the filament all the way through the Bowden tube to the extruder's BondTech gears.

This topic was modified 5 years ago 2 times by Chiral Symmetry
Posted : 20/11/2019 5:11 pm
Nikolai
(@nikolai)
Noble Member
RE: Are there G-codes for *specific* MMU2S operations?

Looking at the current MMU2 firmware: https://github.com/prusa3d/MM-control-01/blob/master/MM-control-01/main.cpp

This commands are currently implemented:

  • T<nr.> change to filament <nr.>
  • L<nr.> Load filament <nr.>
  • M<0/1> set to normal/stealth mode
  • U<nr.> Unload filament. <nr.> is ignored but mandatory.
  • X0 MMU reset
  • P0 Read finda
  • S0 return ok
  • S1 Read version
  • S2 Read build nr.
  • S3 Read drive errors
  • F<nr.> \<type\> filament type. <nr.> filament number, \<type\> 0, 1 or 2. Does nothing.
  • C0 continue loading current filament (used after T-code)
  • E<nr.> eject filament
  • R0 recover after eject filament
  • W0 Wait for user click
  • K<nr.> cut filament

If you need any special behavior and the current commands are not sufficient, you need to adjust the firmware.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 20/11/2019 6:21 pm
Chiral Symmetry
(@chiral-symmetry)
Active Member
Topic starter answered:
RE: Are there G-codes for *specific* MMU2S operations?

@nikolai-r

Thanks!  I'll see what I can do with that.

Posted : 20/11/2019 8:28 pm
Brian Chu
(@brian-chu)
Member
RE: Are there G-codes for *specific* MMU2S operations?

 

 

  • F<nr.> \<type\> filament type. <nr.> filament number, \<type\> 0, 1 or 2. Does nothing.

 

this line is what I'm looking for for a long time, trying to solve the problem of loading flexibles, so disappointed.

Posted : 23/03/2022 7:11 am
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