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B2D stands for "Belted Dual Drive". It's a bowden style extruder that has extra grip to filament and is hardly audible during retraction.
Preview the 3D model on Sketchfab: https://sketchfab.com/models/8568dba4796e4a238a1051e965c39b2c
FEATURES:
Dual drive gear for improved grip, and prevent grinding filament. Frequent retraction is more reliable
Belt driven motion don't generate any noise itself during retraction. The only noise left from extruder would come from the stepper motor vibrating the frame of printer
3:1 gear ratio to increase torque
Very durable. No wear on belt and pulley over time comparing to printed gears
Adjustable compression of a strong spring
Modular parts for different combination of drive gear, filament and bowden tube
The bowden connector can slide for 3.5mm. Any diameter of drive gear between 7-12mm is applicable
Quick changeable drive gears. Can use large gear with slower motor speed for silent operation, and small gears with more torque for super fast extrusion rate.
Operation video…