Dual extrusion

Before going for quad extrusion it may be worth to experiment with dual extrusion. Especially if your controller already supports dual extruders without any additional hardware. Here's how I did this
Extruders: www.thingiverse.com/thing:201...
2 into 1 www.thingiverse.com/thing:208...
test object www.thingiverse.com/thing:248...
Facebook Hypercube group / 1871049783171141

[@kazolar]

How do you ensure that you get consistent retracts and re-inserts. Just basic retract and insert commands eventually lead to a clog in my tests because the filament comes out with whips at the end of it -- that's the key to making this reliable/repeatable. (hence why I picked up the specially machined and polished multimaterial heatbreak) -- there is special gcode to to do purge retract to ensure a clean retract to avoid clogs.

[@arturslab7102]

Yes, I'm struggling with this as well. Apparently retracting your filament as fast as possible helps. I noticed that Prusa version of Slic3r does some back-and-forth movements perhaps to clean up the tip. Also, someone recommended a special heatbreak in my prior video comments.
Also, I've noticed that this dual Y adapter I'm using here seems a bit less prone to clogs than the 4 way adapter in the other video. Maybe the PLA that was used, maybe the pneumatic connectors - not sure what makes the difference. With this 2 way adapter I was able to print multi color lizard. With he 4 way adapter I can't even get the test print I show in this video to finish... yet :)
This is all work in progress. I'm posting what I have so far with the hope that the more people start working on this the sooner we'll find a good solution.

[@3dgussner958]

Hi Arthur,
you should try Slic3r Prusa Edition and check their Multi Material config...github.com/prusa3d/Slic3r-settings/tree/master/Slic3r%20settings%20MK2MM You can use Slic3r PE with any printer just configure it a bit.

[@arturslab7102]

Thanks for the tip. I did try it. It won't work because it only retracts/ejects 90mm on tool change. I need 140. Unless you know of a way to pass that parameter to this version of slicer. I could not find anything.

[@3dgussner958]

As far i can see in the they changed in their Slic3r retract_before_travel from 1 to 3,3,3,3; retract_layer_change from 1 to 0; retract_length from 0.8 to 4,4,4,4 and retract_length_toolchange from 3 to 4,4,4,4...they also don't use tool change script, but maybe of implementing in firmware. Maybe it is an option to generate a simple gcode and looking for the line where it changes the extruder...by changing these values above you could find which one you need to adjust to get your 140mm.
You also can look for hints in the Prusa firmware searching for 'SNMM'...Here some thing i found
#define FIL_LOAD_LENGTH 102 //length for loading filament into the nozzle
#define FIL_COOLING 10 //length for cooling moves
these are used to calculate the extruder moves while changing tools and filament...there is for sure more
Hope that helps

[@arturslab7102]

That's the problem. Prusa added a ton of custom code to their version of Marlin. That never got back-ported to real Marlin. They also removed support for all boards other than the ones they use. So I'd have to back-port new code or re-add board suport. Either way a messy undertaking.
But thanks for finding those defines. That narrows things down a bit should I go this route.