Mini dual Y adapter for E3D V6 style hotend with bowden extruders by gimle

Last crawled date: 3 years ago

Inspired by the Dagnall Y Extruder.
The coupling is roughly 4cm tall and mounts directly on the alu heat sink.
Bottom pneumatic coupling drilled through and sawed off top part to save space. Ridges sawed on the hex nut part to ensure the plastic is able to get a good grip. Heated and pressfitted in place.
1mm holes for superglue to secure PTFE tubing and bottom coupling (use a needle to help it penetrate). Might be overkill.
Recommend if necessary drilling through the alu heatsink with a 4mm drill to widen the hole and get the PTFE tube down to the heat break barrel (mine did not have that feature), and cut the tubing to length for a tight fit down there when screwed in place.
Minimum retraction needed for filament switching is about 8cm - but to avoid headaches use 10+.
Seems to be very robust - easily survived many filament crashes caused by bad gcode/slicing. Even survived several hard crashes where an angry gorilla was trying to "help"/force the filament through when the extruder started grinding plastic - for obvious reasons... Dual extrusion without a mixing head is hard.
Some gcode snippets/hacks that worked for me (11cm retraction, direct drive extruder).
Code assumes the second extruder filament is down in the hotend, and first filament halfway down the pneumatic coupling/at the end of its bowden tube.
Startup:
T1 ;Select second tool. Expect this to be down in the hotend
G92 E0; Reset extruder
G1 E-110 F4200; Retract T1 to park position
T0 ;Select first tool, expect to be roughly in the park posiition and push down into heatbliock
G92 E0; Reset extruder
G1 E90 F3000; Advance T0
G92 E0; Reset extruder
G1 E20 F400; Advance T0 slowly and hope it extrudes some filament...
G92 E0; Reset extruder
Slic3r custom tool change gcode:
T[previous_extruder]
G92 E0
G1 E-110 F4200
G92 E0
T[next_extruder]
G92 E0
G1 E110 F4200
G92 E0