Abstract: According to some aspects, techniques are provided for fabricating sinterable metallic parts through the application of directed energy to a build material. In particular, applying energy to a build material comprising a polymer mixed with a metal powder may cause the polymer to form a cohesive structure with the metal powder. As a result, the polymer acts as a “glue” to produce a metallic green part without local melting of the metal. The green part may subsequently be sintered to remove the polymer and produce a fully dense metal part. Optionally, a step of debinding may also be performed prior to, or simultaneously with, sintering.

Abstract: A build box associated with a powder bed fabrication system may comprise a housing defining a housing cavity, and a powder print bed disposed within the housing cavity. The powder print bed may be characterized by state information. The build box may further comprise a medium configured to facilitate access to the state information, and a coupling interface for removably engaging the build box with at least one subsystem of the powder bed fabrication system. The state information may comprise one or more state information elements of object identification, object location, current processing state, next subsystem processing step, previous subsystem processing step, object model information, object material composition, and current powder print bed temperature profile. The medium may comprise a memory device coupled with a transceiver. The medium may alternatively comprise an RFID device, or an optically perceivable designator, such as a bar code or QR code.

Abstract: Devices, systems, and methods are directed to the pneumatic ejection of liquid metal from a nozzle moving along a controlled three-dimensional pattern to fabricate a three-dimensional object through additive manufacturing. The metal is movable into the nozzle as a valve is actuated to control movement of pressurized gas into the nozzle. Such movement of metal into the valve as pressurized gas is being moved into the nozzle to create an ejection force on liquid metal in the nozzle can reduce or eliminate the need to replenish a supply of the metal in the nozzle and, therefore can facilitate continuous or substantially continuous liquid metal ejection for the fabrication of parts.

Abstract: In a three-dimensional (3D) printing system and method for printing a 3D object, a material in solid form is elevated in temperature to a point at which the material melts or partially melts and begins to flow from a nozzle as a result of an actuating force or displacement resulting in a force. Since the transfer of heat to the material is central to melting and flow of the material, and the printing process ultimately, it is useful that the material be elevated to the appropriate temperature. By anticipating large fluxes of material through the nozzle and adjusting a heating rate in advance of an increased deposition rate, the material remains melted, and extrusion of the material via the nozzle is not limited by heating.

Abstract: A system for de-powdering one or more objects within a powder print bed comprises a build box configured to contain the powder print bed, and a de-powdering subsystem configured to engage the build box. The de-powdering subsystem comprises a vacuum device configured to withdraw loose powder agitated by the air jet device, and a robotic arm configured to convey the vacuum device to one or more locations on the powder print bed. The system may further comprise an air jet device disposed on the robotic arm, the air jet device configured to agitate, with a jet of air, unbound powder within the powder print bed. The system may further comprise a mechanical agitation instrument configured to facilitate agitation of the unbound powder within the powder print bed. The mechanical agitation instrument may be used in conjunction with one or both of the vacuum device and the air jet device.

Abstract: A variety of additive manufacturing techniques can be adapted to fabricate a substantially net shape object from a computerized model using materials that can be debound and sintered into a fully dense metallic part or the like. However, during sintering, the net shape will shrink as binder escapes and the base material fuses into a dense final part. If the foundation beneath the object does not shrink in a corresponding fashion, the resulting stresses throughout the object can lead to fracturing, warping or other physical damage to the object resulting in a failed fabrication. To address this issue, a variety of techniques are disclosed for substrates and build plates that contract in a manner complementary to the object during debinding and sintering.

Abstract: A system for separating objects within a stacked powder print bed of nested objects comprises a build box configured to contain the powder print bed. The build box has a build box top and a build box floor. The system further includes an elongated aperture formed in a side wall of the build box, and a de-powdering subsystem configured to mechanically and electrically engage the build box. A separating blade associated with the de-powdering subsystem is configured to be inserted through the elongated aperture and into the powder print bed between a top-most print bed layer of the nested objects and a second print bed layer directly below and contiguous with the top-most layer, thereby forming an isolated powder print bed between the separating blade and the build box top. The unbound powder may be agitated by various techniques and subsequently removed from the objects.

Abstract: Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is fabricated between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering. Interface layers suitable for manufacture with an additive manufacturing system may resist the formation of bonds between a support structure and an object during subsequent sintering processes.

Abstract: Support structures are used in certain additive fabrication processes to permit fabrication of a greater range of object geometries. For additive fabrication processes with materials that are subsequently sintered into a final part, an interface layer is formed between the object and support in order to inhibit bonding between adjacent surfaces of the support structure and the object during sintering. The support structure may be a multi-part support structure to mitigate mold lock or facilitate removal from enclosed spaces.

Abstract: Techniques are disclosed for fabricating multi-part assemblies. In particular, by forming release layers between features such as bearings or gear teeth, complex mechanical assemblies can be fabricated in a single additive manufacturing process.

Abstract: In a three-dimensional (3D) printing system and method for printing a 3D object, a material in solid form is elevated in temperature to a point at which the material melts or partially melts and begins to flow from a nozzle as a result of an actuating force or displacement resulting in a force. Since the transfer of heat to the material is central to melting and flow of the material, and the printing process ultimately, it is useful that the material be elevated to the appropriate temperature. By anticipating large fluxes of material through the nozzle and adjusting a heating rate in advance of an increased deposition rate, the material remains melted, and extrusion of the material via the nozzle is not limited by heating.

Abstract: A printer fabricates an object from a computerized model using a fused filament fabrication process. The shape of an extrusion nozzle may be varied during extrusion to control, e.g., an amount of build material deposited, a shape of extrudate exiting the nozzle, a feature resolution, and the like.

Abstract: Devices, systems, and methods are directed at spreading sequential layers of powder across a powder bed and applying energy to each layer to form a three-dimensional object. The powder can include granules including agglomerations of metallic particles to facilitate spreading the metallic particles in each layer. The energy can be directed to the powder to reflow the granules in each layer to bind the metallic particles in the layer to one another and to one or more adjacent layers to form the three-dimensional object. Thus, in general, the agglomeration of the metallic particles in the granules can overcome constraints associated with metallic particles that are of a size ordinarily unsuitable for flowing and/or a size that presents safety risks. By overcoming these constraints, the granules can improve formation of dense finished parts from a powder and can result in formation of unique microstructures in finished parts.

Abstract: Devices, systems, and methods are directed at spreading sequential layers of powder across a powder bed and applying energy to each layer to form a three-dimensional object. The powder can include granules including agglomerations of metallic particles to facilitate spreading the metallic particles in each layer. The energy can be directed to the powder to reflow the granules in each layer to bind the metallic particles in the layer to one another and to one or more adjacent layers to form the three-dimensional object. Thus, in general, the agglomeration of the metallic particles in the granules can overcome constraints associated with metallic particles that are of a size ordinarily unsuitable for flowing and/or a size that presents safety risks. By overcoming these constraints, the granules can improve formation of dense finished parts from a powder and can result in formation of unique microstructures in finished parts.

Abstract: Devices, systems, and methods are directed at spreading sequential layers of powder across a powder bed and applying energy to each layer to form a three-dimensional object. The powder can include granules including agglomerations of metallic particles to facilitate spreading the metallic particles in each layer. The energy can be directed to the powder to reflow the granules in each layer to bind the metallic particles in the layer to one another and to one or more adjacent layers to form the three-dimensional object. Thus, in general, the agglomeration of the metallic particles in the granules can overcome constraints associated with metallic particles that are of a size ordinarily unsuitable for flowing and/or a size that presents safety risks. By overcoming these constraints, the granules can improve formation of dense finished parts from a powder and can result in formation of unique microstructures in finished parts.

Abstract: Additive fabrication systems generally use support structures to expand the available range of features and geometries in fabricated objects. For example, when a vertical shelf or cantilever extends from an object, a supplemental support structure may be required to provide a surface for fabrication thereon. This process may become more difficult when, e.g., a part will be subjected to downstream processing steps such as debinding or sintering that impose different design rules. To address these challenges and provide a greater range of flexibility and processing speed, it may be useful in certain circumstances to independently fabricate the object and support structures, and then assemble these structures into a composite item for debinding and sintering. This approach also advantageously facilitates various techniques for spraying, dipping, or otherwise applying a release layer between the support structure and the part so that these separate items do not become fused together during sintering.

Abstract: For conditioning build material for fused filament fabrication, thermal power is both added to and removed from a nozzle in a manner that can reduce sensitivity of the nozzle temperature to fluctuations in build material feed rate. The amount of thermal power added is at least as large as the sum of the amount removed, the amount to condition the material, and losses to the environment. The amount removed may be at least as large as half the thermal power required to condition the material to extrusion temperature, and may be comparable to, or much larger than the conditioning amount. The larger the ratio of the amount removed to the conditioning amount, the less sensitive the nozzle temperature will be to fluctuations in build material feed rate. Fine temperature control arises, enabling building with metal-containing multi-phase materials or other materials that have a narrow working temperature range.