/diy/ - Do It Yourself

>>2615812
There isn't much, it's been a thing for a long time, but it's in no way mature.

The biggest problem is the vast majority don't do shit to actually mix filament, it gets combined into an incoherent coextruded striped mess.
The Diamond hotend is one of the oldest and most notable examples, and it's great fun if you enjoy heat-creep, color leaking, poor mixing, clogs, all shared by the majority of other color-mixing hotends.
The E3D Cyclops isn't much better. Fun as hell to tinker with, but far from great.

There are still people working around the idea, obviously there's a lot of room for improvement.
Picrel.webm someone recently created a co-extruder that basically wraps one color around another with controllable thickness, very cool shit, works well in their demonstration.
The PLEC project intends to be akin to the MMU or ERCF, but actually mixes filaments rather than just switching between them, shows promise.