Mixing vitrual extruder : how does it work

Hello,

i'm new here and i would appreciate any help))

sorry for my english.

I've built the printer and now i try to make some changes.

Idea: to mix 2 fillament. For ex. 2:1, 7:3 etc.

What i found: DiamonHotEnd mixing color firmware 3 extruder + one nozzle. It looks good. I made all settings.

I need to change code, but i can't really understand how virtual extruders work. Could you please explain step by step ?

There is a code:

; Ocen
M163 S0 P5// why we set  Extruder1 weight ="5" and what does it mean for printer
M163 S1 P1//why we set  Extruder2 weight ="1" and what does it mean for printer
M163 S2 P0 // why we set  Extruder3 weight ="0" and what does it mean for printer
M164 S0 // what does  this string?

because later we have

; Blue
M163 S0 P1//
M163 S1 P1
M163 S2 P0
M164 S2

and now we set both Extruder1 = 1,Extruder2=1
why in previous code we set Extruder 1=5?



And then in gcode in slic3r later how it will be work? what is happens when we choose E

; generated by Slic3r 1.2.9 on 2017-01-20 at 14:41:14

; external perimeters extrusion width = 0.50mm
; perimeters extrusion width = 0.72mm
; infill extrusion width = 0.72mm
; solid infill extrusion width = 0.72mm
; top infill extrusion width = 0.72mm

M107
M104 S200 T1 ; set temperature
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

M109 S200 T1 ; wait for temperature to be reached
G21 ; set units to millimeters
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
T1
G92 E0
G1 Z0.350 F7800.000
G1 E-2.00000 F2400.00000
G92 E0
G1 X89.915 Y90.753 F7800.000
G1 E2.00000 F2400.00000
G1 X91.668 Y89.274 E2.07096 F1800.000
G1 X93.820 Y88.481 E2.14192
G1 X95.000 Y88.375 E2.17858

How would printer proces this code above? what is happens when there is E in line code (G1 E2.00000 F2400.00000 ) how does it know which motor should on and how much steps?



Thank you.

I haven't spent much time with Marlins color mixing method, but here is what I got:

; Blue
M163 S0 P1// 
M163 S1 P1
M163 S2 P0
M164 S2

There are three real extruders ( S0-S2) and their mixing ratio is defined by the P parameter. In the above example it should be 50% 50% 0%. ( 1:1:0 )
Then these three extruders are assigned to a virtual extruder "S2" with the M164 S2 line.

Later in the gcode, when the tool is switched to T2, the mixing ratio of S2 is chosen.

I hope, I'm right, because there is another mixing command M165...
The explanation of these three commands are very sparse, I hope someone can share his knowledge with us....