Filament swapping in three-dimensional printing

A method comprising:

• securing a filament tube within an opening of a tool rack having a plurality of openings each defining a corresponding insertion path, the filament tube securable in a predetermined alignment with an extruder through a coupling between a first connector of the extruder and a second connector of the filament tube, the predetermined alignment of the filament tube and the extruder defining a feed path for a filament through the filament tube and the extruder;
• positioning the extruder at a predetermined distance beneath the opening defined by the tool rack, where, at the predetermined distance, the first connector of the extruder is secured to the second connector of the filament tube such that the filament tube is coupled in the predetermined alignment with the extruder;
• moving the extruder, coupled with the filament tube, along the corresponding insertion path for exiting the tool rack while maintaining the coupling of the extruder and the filament tube;
• advancing the filament through the extruder and melting the filament for extrusion through an extrusion port defined by the extruder;
• retracting the filament from the extruder;
• positioning the extruder, coupled with the filament tube, along the corresponding insertion path and into the opening defined by the tool rack such that a fixture of the filament tube is disposed in the opening and secured from movement in a direction opposing the corresponding insertion path by a structure of the tool rack surrounding a portion of the opening;
• and
• moving the extruder, in the direction opposing the corresponding insertion path, to decouple the filament tube from the extruder.