Infinite screw in RRF

[Timothee Leblond]

Hey!

I'm bringing back my old problem about dual extrusion and mixing ratio.
As the lattest does not work, I had the idea mapping on of my extruder like a axis as it I'd it to behave as an endless screw. Do you think it is doable? How would you organize the Gcode?

Thank you!

[dc42]

@Timothee-Leblond please explain what you mean by "does not work". What exactly are you trying to do?

Running an extruder as an axis gives rise to a number of issue so is not advised.

[Timothee Leblond]

@dc42

Thanks for your answer!

I'm running a printer on a Mini 5+ with 2 extruders mounted on the same carriage. The goal is to print both materials simultaneously but also independently (sort of an IDEX but with only one carriage). The reason behind this is that this is a bioprinter, and that both extruders deposit different material format. One is a gel and the other is a continuous material. So far I tried mapping both extruders on the same tool and control them through a mixing ratio. This is not convenient as I do not want both extrusion factor to be linked and rely on each other. I also tried having the extruders set to tools but the command at sent sequentially (which I don't want either).

Instead, I'd like to control the gel extrusion traditionally (through G1 E commands). In parallel, I'd like to send a long-distance command with the other extruder that would run in addition (at the same time) to the other gcode commands.

This is the reason why I tried mapping one extruder on a tool and the other on an axis, hoping I could use them both in parallel.

Here is an example (does not work as T2 G1 waits for previous T1 G1 to be completed)

T1 
G91
G1 E4700 F240 ; Long distance command to be ran in background
 
G90
T2 ; Run this with second extruder in parallel to the first long distance command
G1 E1.2
G1 E2.4
G1 E3.6
G1 E4.8
 

Thank you for your precious help!

[T3P3Tony]

@dc42 part of the discussion is here:

https://forum.duet3d.com/topic/37627/simultaneous-dual-extrusion/9?_=1742826213982

[droftarts]

@Timothee-Leblond RepRapFirmware supports multiple motion systems, see https://docs.duet3d.com/en/User_manual/RepRapFirmware/Multiple_motion_systems

I think you may be able to run the first tool and the XYZ motion system in one motion system, and the continuous tool in the second motion system. To use your example, it could be written as (NOT TESTED!):

M606 S1 ; enable forking of the file to each motion system queue
 
M596 P1 ; use second motion system
T1 
G91
G1 E4700 F240 ; Long distance command to be ran in background
G90
 
M596 P0 ; use second motion system
T2 ; Run this with second extruder in parallel to the first long distance command
G1 E1.2
G1 E2.4
G1 E3.6
G1 E4.8
 
M400 ; wait for both motion systems to finish, release motion systems

Ian