Coil Bushing - Reduces extruder force

cults3d

Normally, bobbin holders on standard 3D printers feature a smaller axis than the bobbin hole designed specifically for various types of coils. This discrepancy causes the coil axis to deviate from the axis of rotation, resulting in increased force required by the extruder to pull the filament. To mitigate this issue, I have created an adapter bushing that inserts into the coil's hole, effectively aligning the coil axis with the axis of rotation and significantly reducing the extruder's pulling force. Calculations indicate a nearly 50% reduction in force. The underlying physical principle involves a decrease in moment of inertia, which is further explained through an accompanying image. This design was optimized for the BQ PLA coil; however, users with different types of coils will need to modify and adapt the design accordingly. To facilitate modifications, I have provided the CAD file in STEP and Catia formats.