Handling retraction with mixing extruder

I have a zonestar z5fm2 running marlin 1.1.8 with a mixing extruder.

That is, 2 extruder stepper motors feeding a 2-in 1-out hotend (similar to the E3D cyclops).

I'm slicing with simplify3d and I have set up:
T0 set to the first extruder;
T1 set to the second extruder;
T2 set to a virtual extruder consisting of a 50/50 mix of extruder 1 and 2 (made by having this in the start code: M163 S0 P50 followed by M164 S2)

I was wondering how you handle the retraction. Currently only the active tool (eg. extruder motor 1 when using T1) retracts, which leads to a lot of oozing since the filament in the unused half is still applying some pressure.

I read that for a setup like mine it is necessary to get both extruders to retract. How do I do that?

I've seen the documentation for programming G10/G11 firmware retract with M207 but there does not seem to be a way to specify the tool to use.

I could make a find-and-replace post processing script in simplify3d to replace retracts of T0 or T1 with retracts of T2 (so both motors retract), but then how would I get it to switch back to the proper original tool when resuming printing?

Is there a way to address an extruder directly in G1 commands (so I could force both to retract), or temporarily switch a tool for just one command (so I could switch tool for the retract command only and it would go back to printing with the previous tool afterwards)?

I used to do directly with gcodes and retraction wa handled directly by the slicers, , you have to enable this on mixin struder section

#define DIRECT_MIXING_IN_G1

then just put this gcode at the point you have to mix

M165 A0.75 B0.25;
M165 A0.5 B0.5;
M165 A0.25 B0.75;
M165 A0 B1;
M165 A1 B0;

where A is your Eo and B is E1 and the sum of bouhs is 1 the irst is 75% 25% , second is 50% 50% and so on, the last 2 i used to use for change color directly

Quote
LMF5000
I have a zonestar z5fm2 running marlin 1.1.8 with a mixing extruder.

That is, 2 extruder stepper motors feeding a 2-in 1-out hotend (similar to the E3D cyclops).

I'm slicing with simplify3d and I have set up:
T0 set to the first extruder;
T1 set to the second extruder;
T2 set to a virtual extruder consisting of a 50/50 mix of extruder 1 and 2 (made by having this in the start code: M163 S0 P50 followed by M164 S2)

I was wondering how you handle the retraction. Currently only the active tool (eg. extruder motor 1 when using T1) retracts, which leads to a lot of oozing since the filament in the unused half is still applying some pressure.

I read that for a setup like mine it is necessary to get both extruders to retract. How do I do that?

I've seen the documentation for programming G10/G11 firmware retract with M207 but there does not seem to be a way to specify the tool to use.

I could make a find-and-replace post processing script in simplify3d to replace retracts of T0 or T1 with retracts of T2 (so both motors retract), but then how would I get it to switch back to the proper original tool when resuming printing?

Is there a way to address an extruder directly in G1 commands (so I could force both to retract), or temporarily switch a tool for just one command (so I could switch tool for the retract command only and it would go back to printing with the previous tool afterwards)?

I just installed a Cyclops on my RepRap Cartesian printer and got it working quite well. I definitely saw the jamming you speak of. This happens when you retract too far. In fact, lots of things go wrong when you retract too far, especially when you pull one filament back, and move the next forward. The E3D site gives your biggest hint: Do 2mm normal retracts and 3mm tool-change retracts. You want to keep the filament close to the heater block for two reasons, 1: the further you pull it back, the more likely you will get a "blob" cool that refuses to move either direction. 2: The Cyclops has a common chamber for both filaments. If you pull one filament back 8mm, the other filament will "back-fill" all the way back up that 8mm before pressure pushes it out of the nozzle. Now you take a lot of filament to get the one that you want to come out, and you may cause a jam in the other filament path. Ick.

I have found that I do not need to do any extra scripting with S3D on my Cyclops (I DID have to do special scripting with the Chimera, dual nozzle).
I use a Bowden setup, so I added an extra mm to my retracts. In your Extruder tab, I have each extruder do a 3mm retraction and a 0.1mm Z-hop on retract. On the "Other" tab, I set my tool change to do a 4mm retract and a -0.5 Tool Change Extra Restart Distance, this stops the filament advance a little bit early.

I then set up a priming tower (10x10 works well for me) and an ooze shield that is 5mm from the part. I like the "waterfall" wall because it uses less filament and looks cool at the end...

You must configure Simplify3D for two extruders, but only one extruder heater.
(EDIT)
I have found the S3D often will not correctly change the hot end temperature with the Cyclops unless you define BOTH extruders in the temperature tab. In the firmware settings below, the F/W knows to treat both T0 and T1 as the same heater, so this works out fine. I typically set the first layer down hotter to make it stick that much better.
(EDIT)

I configured my Marlin 1.1.8 configuration.h thus:
#define EXTRUDERS 2
#define SINGLENOZZLE
#define HOTEND_OFFSET_X {0.0, 0.0} ;No nozzle offsets
#define HOTEND_OFFSET_Y {0.0, 0.0}
#define DISABLE_E false ; never disable steppers
#define DISABLE_INACTIVE_EXTRUDER false ;Keep the heaters on

This should get you started.
DLC

Edited 3 time(s). Last edit at 01/15/2020 10:50AM by dlc60.

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