Novel Ooze-Elimination Dual Extruder Retraction

Dear RepRap developers,

Yesterday, I had an idea. I've been considering upgrading my Wilson TS to a dual head setup. Watching various videos on multi-head extrusion, I've come to notice a recurring problem is that the head not in use still oozes or drags material after it's been disabled. That often results in undesired results.

In order to alleviate this problem, I thought a mechanical retraction mechanism of the head could be used. Without going into the details of the mechanics, the focus here is to develop the firmware modifications required to make this possible. Also, I have never printed using two heads, but I'm assuming that the Slicing software (Slic3r) produces a Gcode Commands to Enable or Dissable the heads.

Essentially, when extruder 1 is done extruding, a small DC motor would actuate and lift the extruder up so it moves in Z while the X carriage stays at its current Z position. The Extruder 2, who was also in its retracted mode would then position itself where the Extruder 1 was and then lower back to the Z position Extruder 1 initially was at. Quite straight forward.



I'm by no means a software programmer and although I've coded some light arduino programs and basic algorithms in C, I'll require help from the community in order to implement this change. I see this as an opportunity to explore the internals of the firmware as well.

What are your thoughts about this? And, if you're in, where should we start?

Not sur eif a dc motor is the best solution. A simple servo should also be able to lift the extruder. And above this servo control is included in firmware already and you can also define extra commands to enable/disable extruder which can contain positioning servos. So no extra programming required.

Only problem is you sollution will still drip, but at least the 2nd head will not scratch on surface. Maybe you can also add a small shield that get sunder the nozzle when beeing lifted to prvent oozing completely:-)

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I love your idea, iv been wanting to implement something similar myself for a while but iv just not had the time.

Rather than using a servo to lift the unused extruder I was hoping to design a mechanical trigger that could simply be fastened to the very end of the x axis.
Then to change extruder all you would need to do is send the carriage to the end of the axis where it would bump into the trigger, then a simple over center spring type mechanism in the carriage would lift the nozzle.

Then as repetier mentioned a small shield to stop ooz. The dual x carriage bukobot uses bit of metal from a whisk!

[bukobot.com]