Abstract: An extruder of a three-dimensional printer may be coupled with one or more filament tubes, each filament tube having its own supply of filament. The extruder may include a drive gear rotatable in a first direction to advance a filament from a filament tube toward at least one extrusion opening defined by the extruder and rotatable in a second direction, opposite the first direction, to advance another filament from a different filament tube toward the at least one extrusion opening defined by the extruder. Also, as one filament is advanced by the drive gear, another filament may be retracted by the drive gear to improve the switching of filaments in a three-dimensional printing process. The extruder may work in conjunction with a filament supply-side drive system that feeds filament into one or more filament tubes, reducing a pull force exerted by the drive gear of the extruder.

Abstract: An extruder of a three-dimensional printer may be coupled with one or more filament tubes, each filament tube having its own supply of filament. The extruder may include a drive gear rotatable in a first direction to advance a filament from a filament tube toward at least one extrusion opening defined by the extruder and rotatable in a second direction, opposite the first direction, to advance another filament from a different filament tube toward the at least one extrusion opening defined by the extruder. Also, as one filament is advanced by the drive gear, another filament may be retracted by the drive gear to improve the switching of filaments in a three-dimensional printing process. The extruder may work in conjunction with a filament supply-side drive system that feeds filament into one or more filament tubes, reducing a pull force exerted by the drive gear of the extruder.

Abstract: A raft to support a three-dimensional object on a build platform of a three-dimensional printer can be fabricated with a controlled adhesion pattern to improve overall raft performance. For improved raft-to-build platform adhesion, an exterior portion around the perimeter of the raft may be fabricated with greater adhesion (per unit of surface area covered by the exterior portion) than an interior portion. This can be accomplished by varying the volume of build material, varying the printing height, or using different patterns of build material. At the same time, adhesion of the raft to a printed object built thereon can be controlled with a number of techniques such as using specific build patterns for the top layer of the raft or varying printing heights (e.g., z-axis position) between the top of the raft and the bottom of the object.

Abstract: An extruder of a three-dimensional printer may be coupled with one or more filament tubes, each filament tube having its own supply of filament. The extruder may include a drive gear rotatable in a first direction to advance a filament from a filament tube toward at least one extrusion opening defined by the extruder and rotatable in a second direction, opposite the first direction, to advance another filament from a different filament tube toward the at least one extrusion opening defined by the extruder. Also, as one filament is advanced by the drive gear, another filament may be retracted by the drive gear to improve the switching of filaments in a three-dimensional printing process. The extruder may work in conjunction with a filament supply-side drive system that feeds filament into one or more filament tubes, reducing a pull force exerted by the drive gear of the extruder.

Abstract: A raft to support a three-dimensional object on a build platform of a three-dimensional printer can be fabricated with a controlled adhesion pattern to improve overall raft performance. For improved raft-to-build platform adhesion, an exterior portion around the perimeter of the raft may be fabricated with greater adhesion (per unit of surface area covered by the exterior portion) than an interior portion. This can be accomplished by varying the volume of build material, varying the printing height, or using different patterns of build material. At the same time, adhesion of the raft to a printed object built thereon can be controlled with a number of techniques such as using specific build patterns for the top layer of the raft or varying printing heights (e.g., z-axis position) between the top of the raft and the bottom of the object.