Abstract: Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using generative design processes, where three dimensional (3D) models of the physical structures can be produced to include lattices, hollows, holes, and combinations thereof, include: obtaining design criteria for an object; iteratively modifying 3D topology and shape(s) for the object using generative design process(es) that employ a macrostructure representation, e.g., using level-set method(s), in combination with physical simulation(s) that place void(s) in solid region(s) or solid(s) in void region(s) of the generative model of the object; and providing a 3D model of the generative design for the object for use in manufacturing a physical structure corresponding to the object using one or more computer-controlled manufacturing systems.

Abstract: Methods, systems, and apparatus, including a method of multi-material stereolithographic three dimensional printing comprising, depositing a first material through a first material dispenser of a stereolithographic three dimensional printer onto an optical exposure window to form a first material layer; curing the first material layer to form a first material structure on a build head of the stereolithographic three dimensional printer; depositing a second material through the first material dispenser or a second material dispenser onto the optical exposure window to form a second material layer; and curing the second material layer to form a second material structure on the build head.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for working with three-dimensional object models for printing. One of the methods includes determining a plurality of infill structures in a slice of an object; and determining a path for the tool-head to create the plurality of infill structures including: determining a first portion of the path for deposition of a first infill structure during a first time period; determining a second portion of the path for deposition of one or more second infill structures that are not adjacent to the first infill structure during a second time period; and determining a third portion of the path for deposition of a third infill structure that is adjacent to the first infill structure, wherein the second time period is determined to allow the first infill structure to cool before deposition of the third infill structure.

Abstract: Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using data format conversion (e.g., of output(s) from generative design processes) and user interface techniques that facilitate the production of 3D models of physical structures that are readily usable with 2.5-axis subtractive manufacturing, include: modifying smooth curves, which have been fit to contours representing discrete height layers of an object, to facilitate the 2.5-axis subtractive manufacturing; preparing an editable model of the object using a parametric feature history, which includes a sketch feature, to combine extruded versions of the smooth curves to form a 3D model of the object in a boundary representation format; reshaping a subset of the smooth curves responsive to user input with respect to the sketch feature; and replaying the parametric feature history to reconstruct the 3D model of the object, as changed by the user input.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for working with three-dimensional object models for printing. One of the methods includes determining a plurality of infill structures in a slice of an object; and determining a path for the tool-head to create the plurality of infill structures including: determining a first portion of the path for deposition of a first infill structure during a first time period; determining a second portion of the path for deposition of one or more second infill structures that are not adjacent to the first infill structure during a second time period; and determining a third portion of the path for deposition of a third infill structure that is adjacent to the first infill structure, wherein the second time period is determined to allow the first infill structure to cool before deposition of the third infill structure.

Abstract: Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using data format conversion (e.g., of output(s) from generative design processes) and user interface techniques that facilitate the production of 3D models of physical structures that are readily usable with 2.5-axis subtractive manufacturing, include: modifying smooth curves, which have been fit to contours representing discrete height layers of an object, to facilitate the 2.5-axis subtractive manufacturing; preparing an editable model of the object using a parametric feature history, which includes a sketch feature, to combine extruded versions of the smooth curves to form a 3D model of the object in a boundary representation format; reshaping a subset of the smooth curves responsive to user input with respect to the sketch feature; and replaying the parametric feature history to reconstruct the 3D model of the object, as changed by the user input.

Abstract: Methods, systems, and apparatus, including a method of multi-material stereolithographic three dimensional printing comprising, depositing a first material through a first material dispenser of a stereolithographic three dimensional printer onto an optical exposure window to form a first material layer; curing the first material layer to form a first material structure on a build head of the stereolithographic three dimensional printer; depositing a second material through the first material dispenser or a second material dispenser onto the optical exposure window to form a second material layer; and curing the second material layer to form a second material structure on the build head.

Abstract: Methods, systems, and apparatus, including a method of multi-material stereolithographic three dimensional printing comprising, depositing a first material through a first material dispenser of a stereolithographic three dimensional printer onto an optical exposure window to form a first material layer; curing the first material layer to form a first material structure on a build head of the stereolithographic three dimensional printer; depositing a second material through the first material dispenser or a second material dispenser onto the optical exposure window to form a second material layer; and curing the second material layer to form a second material structure on the build head.

Abstract: Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using generative design processes, where three dimensional (3D) models of the physical structures can be produced to include lattices, hollows, holes, and combinations thereof, include: obtaining design criteria for an object; iteratively modifying 3D topology and shape(s) for the object using generative design process(es) that employ a macrostructure representation, e.g., using level-set method(s), in combination with physical simulation(s) that place void(s) in solid region(s) or solid(s) in void region(s) of the generative model of the object; and providing a 3D model of the generative design for the object for use in manufacturing a physical structure corresponding to the object using one or more computer-controlled manufacturing systems.

Abstract: Systems and method for determining dynamic forces in a liquefier system in additive manufacturing include, in at least one aspect of the subject matter described in this specification, a method including: receiving motor data for a drive motor that pushes a solid material toward a liquefaction zone of the liquefier system, wherein the motor data comprises at least one data point per individual command code of a set of command codes sent for additive manufacturing; receiving pressure data associated with the liquefaction zone of the liquefier system, wherein the pressure data includes at least one data point per individual command code of the set of command codes; analyzing the motor data and the pressure data for the set of command codes; and outputting a result of the analyzing to facilitate further 3D printing by the AM 3D printer using the solid material.

Abstract: Methods, systems, and computer programs for multi-tool additive manufacturing include a method including: slicing a received model into a series of layers; determining one or more separation starting points, each being a location of two adjoining portions of the model that are to be manufactured by respective additive manufacturing robots; and determining an offset for each of the one or more separation starting points in each layer of the series of layers based on a threshold acceptable print time, each offset in a layer determining a seam location in the layer that is different from a seam location in at least one adjacent layer in the series of layers, and seam offsets determined for the series of layers increase an estimated print time, for manufacturing of the series of layers by the two or more additive manufacturing robots, to no more than the threshold acceptable print time.

Abstract: A fused filament fabrication three dimensional printing system includes a build platform, an extruder for one or more deposition materials, the extruder including at least one nozzle movable relative to the build platform, and a controller configured to control the relative movement between the build platform and the nozzle, and to cause material to be extruded out of the nozzle to form a 3D object on the build platform. The build platform includes a first plate on which the 3D object is formed, a second plate that is positioned vertically below the first plate and defines at least one gap between the first and second plates, and a heating element that is configured to heat the second plate. The first plate defines at least one opening that is configured to allow passage of material extruded from the nozzle into the at least one gap between the first and second plates.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a multi-tool additive manufacturing system that executes in a three-dimensional build volume. In one aspect, a system includes a build platform; a support; a first robot coupled with the support and configured to operate in a build volume defined by the build platform, wherein the first robot includes a first additive manufacturing tool; a second robot coupled with the support and configured to operate in the build volume, wherein the second robot includes a second additive manufacturing tool; wherein the first robot and the second robot are programmed to coordinate simultaneous application; and wherein a first tool path of the first additive manufacturing tool in the first region abuts or overlaps with a second tool path of the second additive manufacturing tool in the second region so as to form a bond.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for working with three-dimensional object models for printing. One of the methods includes determining a plurality of infill structures in a slice of an object; and determining a path for the tool-head to create the plurality of infill structures including: determining a first portion of the path for deposition of a first infill structure during a first time period; determining a second portion of the path for deposition of one or more second infill structures that are not adjacent to the first infill structure during a second time period; and determining a third portion of the path for deposition of a third infill structure that is adjacent to the first infill structure, wherein the second time period is determined to allow the first infill structure to cool before deposition of the third infill structure.

Abstract: Methods, systems, and apparatus, including medium-encoded computer program products, for computer aided design of physical structures using data format conversion (e.g., of output(s) from generative design processes) and user interface techniques that facilitate the production of 3D models of physical structures that are readily usable with 2.5-axis subtractive manufacturing, include: modifying smooth curves, which have been fit to contours representing discrete height layers of an object, to facilitate the 2.5-axis subtractive manufacturing; preparing an editable model of the object using a parametric feature history, which includes a sketch feature, to combine extruded versions of the smooth curves to form a 3D model of the object in a boundary representation format; reshaping a subset of the smooth curves responsive to user input with respect to the sketch feature; and replaying the parametric feature history to reconstruct the 3D model of the object, as changed by the user input.

Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for working with three-dimensional object models for printing. One of the methods includes determining a plurality of infill structures in a slice of an object; and determining a path for the tool-head to create the plurality of infill structures including: determining a first portion of the path for deposition of a first infill structure during a first time period; determining a second portion of the path for deposition of one or more second infill structures that are not adjacent to the first infill structure during a second time period; and determining a third portion of the path for deposition of a third infill structure that is adjacent to the first infill structure, wherein the second time period is determined to allow the first infill structure to cool before deposition of the third infill structure.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a multi-tool additive manufacturing system that executes in a three-dimensional build volume. In one aspect, a system includes a build platform; a support; a first robot coupled with the support and configured to operate in a build volume defined by the build platform, wherein the first robot includes a first additive manufacturing tool; a second robot coupled with the support and configured to operate in the build volume, wherein the second robot includes a second additive manufacturing tool; wherein the first robot and the second robot are programmed to coordinate simultaneous application; and wherein a first tool path of the first additive manufacturing tool in the first region abuts or overlaps with a second tool path of the second additive manufacturing tool in the second region so as to form a bond.

Abstract: Methods and systems, including medium-encoded computer program products, for generating internal structures usable in additive manufacturing include: obtaining a three-dimensional (3D) model of an object to be created by a 3D printer; determining a first slice of the 3D model; and generating first slice data that represents a portion of an internal structure in the first slice of the 3D model of the object, the slice data being usable for fabricating the first slice of the object during a 3D printing process, wherein the portion of the internal structure (i) includes cell structures corresponding to a respective point of a plurality of points with corresponding locations within the interior region, wherein each of the cell structures include an empty space inside the cell structure and (ii) includes a determined quantity of the cell structures based on an analysis of the 3D model.

Abstract: Systems and method for determining dynamic forces in a liquefier system in additive manufacturing include, in at least one aspect of the subject matter described in this specification, a method including: receiving motor data for a drive motor that pushes a solid material toward a liquefaction zone of the liquefier system, wherein the motor data comprises at least one data point per individual command code of a set of command codes sent for additive manufacturing; receiving pressure data associated with the liquefaction zone of the liquefier system, wherein the pressure data includes at least one data point per individual command code of the set of command codes; analyzing the motor data and the pressure data for the set of command codes; and outputting a result of the analyzing to facilitate further 3D printing by the AM 3D printer using the solid material.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a multi-tool additive manufacturing system that executes in a three-dimensional build volume. In one aspect, a system includes a build platform; a support; a first robot coupled with the support and configured to operate in a build volume defined by the build platform, wherein the first robot includes a first additive manufacturing tool; a second robot coupled with the support and configured to operate in the build volume, wherein the second robot includes a second additive manufacturing tool; wherein the first robot and the second robot are programmed to coordinate simultaneous application; and wherein a first tool path of the first additive manufacturing tool in the first region abuts or overlaps with a second tool path of the second additive manufacturing tool in the second region so as to form a bond.