摘要 |
A filament drive mechanism comprising a rotatable component comprising a central hole defined at least in part by an internally-threaded surface, and is configured to receive a filament strand through the central hole to engage the internally-threaded surface with the filament strand. The filament drive mechanism further comprises at least one rotation mechanism configured to rotate the rotatable component, thereby allowing the engaged internally-threaded surface to drive the filament strand through the central hole of the rotatable component.
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