Thing-O-Matic: Bicolored Prints

This isn’t rocket science and it’s certainly not original, but I finally screwed up enough courage to start routinely swapping in a new filament color without pulling out the old one. The trick is to cut both ends flush (with a flush-cutting wire cutter) and maintain gentle pressure on the new filament so it slides right into the grip of the extruder drive gear.

Seeing as how I need tchotchkes in a big way, I run off a plate of Chalk People whenever it’s time for a new color:

Multicolored Chalk People
Multicolored Chalk People

The transition between yellow and black was rather weird. Fortunately, the gory details remain hidden inside that quartet of Chalk Women.

These have all the right attributes for a tchotchke: fast printing, not much plastic, smooth edges, a little fill to show how it works, a few small defects for education.

2 thoughts on “Thing-O-Matic: Bicolored Prints

    1. And, relevant to the Extruder Zit question, the bottom filament pops up out of the extruder when the top filament retracts. I can see about 5 mm of the filament below the extruder drive gear if I stick my nose into the box at the right angle.

      The filament retraction distance is about 3.5 mm (25 rpm / 60 s/min * 0.125 s * 2pi * 11 mm), so there’s enough pressure to drive the filament more than one diameter back out of the extruder! Some of that is due to molten plastic pressure, some to filament mechanical compression / bending in the PTFE tube, and probably some from sheer perversity, but it goes a long way toward explaining where those end-of-thread zits come from.

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