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Heya everyone!
Lately I’ve been finding myself with a bit of spare time, and wanting to give my Prusa i3 DIY machine a bit more capability, I tackled the problem of multimaterial printing, and just the right thing came to mind:
A bowden Y-Splitter based approach similar to Prusa Research’s, combined with my direct drive extruder, and some (currently) DIY wiring to connect the additional motors.

The system, so far, is actually working! Filament is being switched out, the machine prints, etc.

BUT

I currently have a big problem:
The retraction routine leaves thin, fine filament strings in the bowden tubes, that quickly agglomerate there and form literal furballs, eventually leading to a clog in the Y-Splitter or extruder.

So, before I run off and try to trial-and-error something, why not ask a large community that might come up with more effective and simple ideas!

((FYI I am using a RAMPS 1.4

The motors get controlled by using GPIO pins to toggle cheap A4988 drivers on/off; each one is fed with the STEP/DIR signals of the extruder driver.

One additional material motor costs around 20€, and the RAMPS has enough GPIO for … Six? Seven materials? ))

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