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 variety of techniques are used to manage temperature in and around an extruder for a three-dimensional printer.

Abstract: The strength of a bond between two adjacent layers of a three-dimensional print is weakened by initiating fabrication of a top layer at a height greater than the processing height for the print. This technique may be used in particular at the interface between a raft or other support and an object being fabricated, after which the printing process may return to a regular process height for additional layers used to fabricate the remainder of the object.

Abstract: A multi-extruder includes a passive height control mechanism that adjusts the relative height of its extruders without the use of additional, active components. Further, the height control mechanism may employ ramped control surfaces that mitigate noise and vibration by gradually transferring vertical loads while transferring from one active extruder to another.

Abstract: A removable and replaceable build plate for a three-dimensional printer supports magnetic coupling to a printer and advantageous adhesion for an initial layer of build material.

Abstract: An extruder or other similar tool head of a three-dimensional printer is slidably mounted along a feedpath of build material so that the extruder can move into and out of contact with a build surface according to whether build material is being extruded. The extruder may be spring-biased against the forward feedpath so that the extruder remains above the build surface in the absence of applied forces, and then moves downward into a position for extrusion when build material is fed into the extruder. In another aspect, modular tool heads are disclosed that can be automatically coupled to and removed from the three-dimensional printer by a suitable robotics system. A tool crib may be provided to store multiple tool heads while not in use.

Abstract: A cap for an extruder of a three-dimensional printer is removeable and replaceable on the hot end of the extruder, e.g., for cleaning or other maintenance of the cap or extruder. The cap may be formed of a polymer having a lower thermal conductivity than the hot end of the extruder such that the cap forms a thermal barrier between the hot end of the extruder and an external environment. Further, the cap may protect the hot end of the extruder from damaging contact with deposited build material (e.g., spatters) as well as other undesirable contact during a three-dimensional printing process.

Abstract: A supply of build material such as a spool or cartridge is instrumented with a data tag that includes information about the build material. A three-dimensional printer, or a tag reader in communication therewith (directly or indirectly), can read the information from the tag for a determination as to how to use the build material during fabrication of a three-dimensional object.

Abstract: A three-dimensional printer uses transitional lengths of build material to facilitate changes from one color to another during a fabrication process, and more generally to achieve multi-color objects corresponding to color patterns on the surface of a three-dimensional model. The transitional lengths of build material may be positioned inside a fabricated object, such as for infill, or outside the fabricated object where undesirable aesthetic properties of the transitional lengths will not impact the desired distribution of colors on the surface of the fabricated object.

Abstract: A technique for planarizing build surfaces in three-dimensional printing includes the use of a three-dimensional printer having an extruder with a sensor mechanically coupled thereto, where the sensor is operable to sense a contact force between the extruder and a separate structure. In particular, the sensor may be used to measure the contact force at a plurality of locations across a build surface of the separate structure, so that a difference between the measured contact force at two or more locations can be identified. In response to the difference between the measured contact force at these locations, a control signal may be created to reduce the difference for planarizing the build surface, e.g., by fabricating a layer on the build surface that mitigates irregularities therein, by gap filling on the build surface, or by adjusting a parameter of the three-dimensional printer.

Abstract: The hardware and software properties of a three-dimensional printer can be queried and applied to select suitable directly printable models for the printer, or to identify situations where a new machine-ready model must be generated. The properties may be any properties relevant to fabrication including, e.g., physical properties of the printer, printer firmware, user settings, hardware configurations, and so forth. A printer may respond to configuration queries with a dictionary of capabilities or properties, and this dictionary may be used to select suitable models, or determine when a new model must be created. Similarly, when a printable model is sent to the printer, metadata for the printable model may be compared to printer properties in the dictionary to ensure that the model can be fabricated by the printer.

Abstract: Three-dimensional fabrication resources are improved by adding networking capabilities to three-dimensional printers and providing a variety of tools for networked use of three-dimensional printers. Web-based servers or the like can provide a single point of access for remote users to manage access to distributed content on one hand, and to manage use of distributed fabrication resources on the other.

Abstract: A three-dimensional printer is configured to fill interior cavities of a fabricated object with functional or aesthetic materials during fabrication. In general, a number of layers can be fabricated with an infill pattern that leaves void space within an exterior surface of the object. These void spaces can receive a second material such as an epoxy or adhesive that spans multiple layers of the object to increase structural integrity. Similarly, aesthetic materials may be used to add color, opacity, or other desired properties to a fabricated object. The void spaces can also or instead form molds that are filled with a build material to provide a fabricated object.

Abstract: A variety of techniques are disclosed for visual and functional augmentation of a three-dimensional printer.