Abstract: Techniques for depowdering in additive fabrication are provided. According to some aspects, techniques are provided that separate powder from additively fabricated parts through liquid immersion of the parts. Motion of the liquid, such as liquid currents, may dislodge or otherwise move powder away from additively fabricated parts to which it is adhered or otherwise proximate to. The liquid may also provide a vehicle to carry away powder from the additively fabricated parts. Removed powder may be filtered or otherwise separated from the liquid to allow recirculation of the liquid to the parts and/or to enable re-use of the powder in subsequent additive fabrication processes. Techniques for depowdering through liquid immersion may be automated, thereby mitigating challenges associated with manual depowdering operations.

Abstract: Embodiments of the present disclosure are drawn to systems and methods for adjusting a three-dimensional (3D) model used in metal additive manufacturing to maintain dimensional accuracy and repeatability of a fabricated 3D part. These embodiments may be used to reduce or remove geometric distortions in the fabricated 3D part. One exemplary method may include: receiving, via one or more processors, a selection made by a user; receiving a 3D model of a desired part; retrieving at least one model constant based on the user's selection; receiving an input of at least one process variable setting from a set of process variable settings; generating transformation factors based on the at least one process variable parameter and the at least one model constant; transforming the 3D model of the desired part based on the transformation factors; and generating processing instructions for fabricating the transformed 3D model of the desired part.

Abstract: Methods provide for fabricating objects through additive manufacturing in a manner that compensates for deformations introduced during post-print processing, such as sintering. An initial model may be divided into a plurality of segments, the initial model defining geometry of an object. For each of the segments, modified geometry may be calculated, where the modified geometry compensates for a predicted deformation. Print parameters can then be updated to incorporate the modified geometry, where the print parameters define geometry of the printed object (e.g., configuration settings of the printer, a tool path, an object model). The object may then be printed based on the updated print parameters.

Abstract: A method is provided for printing a three-dimensional object. The method comprises, depositing a layer of metal powder onto a powder bed of a three-dimensional printer. A liquid is heated to generate a vapor. The liquid is removed from the vapor to dry the vapor by heating the vapor above a condensation temperature of the liquid. The dry vapor is deposited onto the powder bed of the three-dimensional printer.

Abstract: Mold lock is remediated by performing a layer-by-layer, two-dimensional analysis to identify unconstrained removal paths for any support structure or material within each two-dimensional layer, and then ensuring that aligned draw paths are present for all adjacent layers, all as more specifically described herein. Where locking conditions are identified, a sequence of modification rules are then applied, such as by breaking support structures into multiple, independently removable pieces. By addressing mold lock as a series of interrelated two-dimensional geometric problems, and reserving three-dimensional remediation strategies for more challenging, complex mold lock conditions, substantial advantages can accrue in terms of computational speed and efficiency.

Abstract: A method of recycling build material powder including collecting in a keg an amount of excess build material powder during the additive manufacturing of a part cake. The part cake and keg are transferred to a de-powdering station. The part cake is de-powdered to release a mixture of reusable powder and contaminants. The mixture is sieved to remove the contaminants and deposit the reusable powder to the keg.

Abstract: Methods and systems are disclosed for generatively designing a model of an assembly of mechanical parts. One method includes receiving a first set of constraints for a first part; determining a spatial relationship between the first part and a second part; updating the first set of constraints for the first part based on at least the spatial relationship between the first part and the second part; updating a second set of constraints for the second part based on at least the updated first set up constraints and/or the spatial relationship between the first part and the second part; and generating a model for the first part based on the updated first set of constraints.

Abstract: Devices, systems, and methods are directed to binder jetting for forming three-dimensional parts having controlled, macroscopically inhomogeneous material composition. In general, a binder may be delivered to each layer of a plurality of layers of a powder of inorganic particles. An active component may be introduced, in a spatially controlled distribution, to at least one of the plurality of layers such that the binder, the powder of inorganic particles, and the active component, in combination, form an object. The object may be thermally processed into a three-dimensional part having a gradient of one or more physicochemical properties of a material at least partially formed from thermally processing the inorganic particles and the active component of the object.

Abstract: The present invention is directed to systems and methods for automatically generating mechanical part designs and manufacturing specifications/instructions that account for geometric distortions that may occur during manufacturing or post-processing.

Abstract: The devices, systems, and methods of the present disclosure are directed to powder spreading and binder distribution techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, a powder may be spread to form a layer along a volume defined by a powder box, a binder may be deposited along the layer to form a layer of a three-dimensional object, and the direction of spreading the layer and depositing the binder may be in a first direction and in a second direction, different from the first direction, thus facilitating rapid formation of the three-dimensional object with each passage of the print carriage over the volume. Powder delivery, powder spreading, thermal energy delivery, and combinations thereof, may facilitate consistently achieving quality standards as the rate of fabrication of the three-dimensional object is increased.

Abstract: Devices, systems, and methods are directed to the use of vapor phase change in binder jetting processes for forming three-dimensional objects. In general, a vapor of a first fluid may be directed to a layer of a powder spread across a build volume. The vapor may condense to reduce mobility of the particles of the powder of the layer. For example, the condensing vapor may reduce the likelihood of particle ejection from the layer and, thus, may reduce the likelihood of clogging or otherwise degrading a printhead used to jet a second fluid (e.g., a binder) to the layer. Further, or instead, the condensing vapor may increase the density of the powder in the layer which, when repeated over a plurality of layers forming a three-dimensional object, may reduce the likelihood of slumping of the part during sintering.

Abstract: Techniques for depowdering additively fabricated parts are described in which powder is separated from parts by creating a large pressure differential between the powder and parts and a nearby location. The pressure differential may cause gas to quickly flow into and/or around the powder and parts, thereby producing a force against the powder and parts. Since the powder is generally much lighter than the parts, this force may be much more effective at moving the powder than moving the parts. As a result, the powder and parts may be separated from one another. The pressure differential may be created in various ways, such as by holding the parts and part in a chamber that is pressurized with air and/or other gas(es). Rapid depressurization of the chamber may produce the aforementioned pressure differential, leading to powder movement away from the parts.

Abstract: Disclosed is a pumping system with reduced contamination. A vacuum pump system includes a mechanical vacuum pump mechanism within a hermetic pump that hermetically isolates the pump mechanism from ambient air. A pump inlet is hermetically sealed to the hermetic pump housing. A pump outlet is hermetically sealed at one end to the hermetic pump housing and at the other end to an inlet of a Peclet seal tube. The vacuum pump system produces a vacuum in a vacuum processing chamber. A sweep gas source injects a sweep gas into at least one of (i) the hermetic pump housing and (ii) the inlet of the Peclet seal tube. The sweep gas and a process gas flow through the Peclet seal tube to substantially isolate against the backflow of the ambient air through the Peclet seal tube.

Abstract: The devices, systems, and methods of the present disclosure are directed to powder spreading and binder distribution techniques for consistent and rapid layer-by-layer fabrication of three-dimensional objects formed through binder jetting. For example, a powder may be spread to form a layer along a volume defined by a powder box, a binder may be deposited along the layer to form a layer of a three-dimensional object, and the direction of spreading the layer and depositing the binder may be in a first direction and in a second direction, different from the first direction, thus facilitating rapid formation of the three-dimensional object with each passage of the print carriage over the volume. Powder delivery, powder spreading, thermal energy delivery, and combinations thereof, may facilitate consistently achieving quality standards as the rate of fabrication of the three-dimensional object is increased.

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: 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: Embodiments of the present disclosure are drawn to systems and methods for adjusting a three-dimensional (3D) model used in metal additive manufacturing to maintain dimensional accuracy and repeatability of a fabricated 3D part. These embodiments may be used to reduce or remove geometric distortions in the fabricated 3D part. One exemplary method may include: receiving, via one or more processors, a selection made by a user; receiving a 3D model of a desired part; retrieving at least one model constant based on the user's selection; receiving an input of at least one process variable setting from a set of process variable settings; generating transformation factors based on the at least one process variable parameter and the at least one model constant; transforming the 3D model of the desired part based on the transformation factors; and generating processing instructions for fabricating the transformed 3D model of the desired part.

Abstract: A retort for thermally processing sinterable objects including a retort body having an interior cavity configured to receive at least one part for sintering. The retort body includes a retort inlet, a fore volume, an inlet plenum, an outlet plenum and a retort outlet. The retort inlet is configured to be fluidly connected to a process gas inlet tube and receive a flow of process gas. The retort inlet is fluidly connected to the fore volume, the fore volume being configured to receive a cleansing object. The fore volume is fluidly connected to the inlet plenum, which is fluidly connected to the interior cavity, which is in turn fluidly connected to the outlet plenum. The outlet plenum is fluidly connected to the retort outlet which is configured to be fluidly connected to an effluent gas outlet tube via a Peclet sealing element.

Abstract: Systems and methods for forming an object using additive manufacturing. One method includes receiving a digital model of the object, predicting a shrinking characteristic or receiving a predicted shrinking characteristic of the object that will occur during thermal processing of the object, once formed, and generating, based on the shrinking characteristic of the object, instructions for forming a raft on which the object will be formed. The instructions for forming the raft are configured to form a raft having a shrinking characteristic that reflects the shrinking characteristic of the object.

Abstract: Assemblies fabricated by additive manufacturing include an object and a base plate providing support to the object during the manufacturing process. The geometry of the base plate is defined to optimize space and material constraints. During sintering, the base plate is reduced in area in a manner complementing the reduction in the footprint of the object, preserving the fidelity of the finished object.