The extruder is the mechanism that pushes filament from the spool into the hotend. It consists of a stepper motor, drive gear and idler; its design determines which materials print reliably.
Direct drive vs bowden
| Direct drive | Bowden | |
|---|---|---|
| Motor position | On the print head | Remote, via PTFE tube |
| Flexible filament (TPU) | Excellent | Harder (long path, flexes) |
| Retraction | Short (0.5–1.5 mm) | Long (3–6 mm) |
| Head weight | Heavier | Lighter → faster |
Why it matters for buyers
If your work includes TPU or frequent material changes, prefer direct drive. If speed is the goal, bowden (or modern high-flow direct drive) is fine. Both handle standard 1.75 mm filament — like VOXFIL TPU, which prints well on direct-drive machines at 15–40 mm/s.