Method for building three-dimensional models in extrusion-based digital manufacturing systems using tracked filaments

A method for building a three-dimensional model in an extrusion-based digital manufacturing system, the method comprising:

• providing a consumable filament to the extrusion-based digital manufacturing system, the consumable filament having a length, an exterior surface, and a plurality of tracks indented from the exterior surface, the plurality of tracks extending along at least a portion of the length, wherein each of the plurality of tracks has an average cross-sectional area that ranges from about 5% to about 30% of an average cross-sectional area of the consumable filament at a non-track location;
• feeding successive portions of the consumable filament to a liquefier retained by the extrusion-based digital manufacturing system with teeth of a rotatable drive mechanism engaged with the plurality of tracks, wherein successive teeth of the rotatable drive mechanism are continuously engaged with successive tracks of the plurality of tracks while feeding the successive portions of the consumable filament;
• melting the consumable filament in the liquefier to provide a melted material;
• extruding the melted material from the liquefier;
• and
• depositing the extruded material in a layer-by-layer manner to form at least a portion of the three-dimensional model, which generates back pressure in the liquefier.

A method for building a three-dimensional model in an extrusion-based digital manufacturing system, the method comprising:

• providing a consumable filament to the extrusion-based digital manufacturing system, the consumable filament having a length, an exterior surface, and a plurality of tracks indented from the exterior surface, the plurality of tracks extending along at least a portion of the length, wherein each of the plurality of tracks has an average cross-sectional area that ranges from about 5% to about 30% of an average cross-sectional area of the consumable filament at a non-track location;
• directing the consumable filament through a filament pathway to an extrusion head retained by the extrusion-based digital manufacturing system, wherein at least a portion of the filament pathway comprises a curved pathway, wherein the consumable filament exhibits a flexibility configured to withstand an elastic strain of t/r, wherein t is a cross-sectional thickness of the consumable material in a plane of curvature at the curved pathway, and wherein r is a bend radius that the consumable filament is subjected to at the curved pathway;
• and
• feeding successive portions of the consumable filament to a liquefier of the extrusion head with teeth of a rotatable drive mechanism of the extrusion head that is engaged with at least a portion of the plurality of tracks, wherein successive teeth of the rotatable drive mechanism are continuously engaged with successive tracks of the plurality of tracks while feeding the successive portions of the consumable filament.