FFF Extruder
Overview
The extruder forces the Filament into the hot end. It usually grips the filament by pinching it between a roller bearing and a knurled, hobbed, or toothed pinch wheel. Torque is usually supplied by a Stepper Motor.[1]
Lifetime and maintenance
The filament sliding through the extruder will eventually sand down a track somewhere. Designs where friction is created between filament and extruder exist. An example of this is the Ormerod extruder design. It bends the filament as a spring to force filament away from the roller bearing and towards the hobbed bolt to achieve better grip. Its extruder body needs replacement every ~1000 hour of operation.
Most designs use PTFE (or sometimes PEEK) tubing to guide the filament. It has proven to be very wear resistant and have constant properties over time.
Lifetime of chosen Stepper Motors and Bearings will affect extruder lifetime and maintenance.
