Abstract: According to one aspect there is provided apparatus for generating a three-dimensional object. The apparatus comprises a first agent distributor to selectively deliver a coalescing agent onto portions of a layer of build material, a second agent distributor to selectively deliver a coalescence modifier agent onto portions of a layer of build material, and a controller to control the agent distributors to selectively deliver each of the agents onto a layer of build material in respective patterns derived from data representing a slice of a three-dimensional object to be generated, so that when energy is applied to the layer the build material coalesces and solidifies to form a slice of the three-dimensional object in accordance the patterns.

Abstract: Methods and apparatus relating to substructures for three-dimensional objects are described. In an example, a processing apparatus includes: an interface to receive data representing a three-dimensional model object, the data including object model data and object property data; a mapping module to map received data to a print material coverage representation; a halftone module to provide halftone threshold data; and a substructure module to define a substructure for a three-dimensional object to be generated, the substructure specifying in at least a region thereof a consistent lattice structure and a variable material distribution. The apparatus is to apply a substructure and a halftoning to the print material coverage representation to generate control data for the production of a three-dimensional object having the substructure.

Abstract: In one example, a non-transitory processor readable medium with instructions thereon that when executed cause an additive manufacturing machine to: form a first layer of build material; form a second layer of build material over the first layer; solidify build material in the second layer to form a slice; and form a barrier that is separable from the slice to prevent a coalescing agent in the second layer penetrating build material in the first layer.

Abstract: An example method for constructing a three-dimensional object in accordance with aspects of the present disclosure includes projecting an image of a section of a three-dimensional object on a building plane through a projection unit, forming a cured section by irradiating laterally an interface of a photopolymerizable material on the building plane with light corresponding to the image of the section of the three-dimensional object, moving a support plane laterally to detach the cured section from the building plane resulting in a gap between the cured section and the building plane, and filling the gap between the cured section and the building plane with photopolymerizable material.

Abstract: Methods and apparatus relating to substructures for three-dimensional objects are described. In an example, a method comprises receiving a lattice model having a consistent dimensionality and determining a substructure model representing a three-dimensional material structure, the substructure model being based on the lattice model and specifying a variable material distribution. The substructure model may be populated with halftone threshold data to provide a three-dimensional halftone threshold matrix.

Abstract: According to one aspect there is provided an apparatus for generating a three-dimensional object. The apparatus may include a first agent distributor to selectively deliver a coalescing agent onto portions of a layer of build material, a second agent distributor to selectively deliver a coalescence modifier agent onto portions of the layer of build material, and a controller to control the first and second distributors to selectively deliver each of the agent and the coalescence modifier onto the layer of build material in respective patterns derived from data representing a slice of a three-dimensional object to be generated, in which when energy is applied to the layer of build material, the build material coalesces and solidifies to form a slice of the three-dimensional object in accordance the patterns and the three-dimensional object has mechanical object properties that are related to the patterns.

Abstract: In one example, an additive manufacturing system includes a processing system to obtain characteristic data including conditions under which a heat reservoir may be added close to a portion of the object, based on the characteristic data, add sacrificial structure data to the three-dimensional object data for a sacrificial heat reservoir structure close to a portion of the object and not connected to the object, and generate multiple slice images from the three-dimensional object data including the sacrificial structure data.

Abstract: Provided in one example herein is a three-dimensional printing method, comprising: (A) forming a layer comprising particles comprising a polymer and cavities between the particles, wherein the particles have an average diameter of between about 5 ?m and about 250 ?m; (B) disposing a liquid suspension over at least a portion of the layer such that the liquid suspension infiltrates into the cavities, wherein the liquid suspension comprises a radiation-absorbing coalescent agent and nanoparticles having an average diameter of less than or equal to about 500 nm; (C) forming an object slice by exposing the infiltrated layer to a radiant energy, wherein the object slice comprises a polymeric matrix comprising the polymeric particles, at least some of which are fused to one another, and the nanoparticles within the polymeric matrix; and (D) repeating (A) to (C) to form the three-dimensional object comprising multiple object slices bound depth-wise to one another.

Abstract: In an example, a method comprises receiving machine-readable data relating to a three-dimensional object to be generated by an additive manufacturing apparatus, the machine-readable data being in a first data format. The method may further include processing, by a processor, the machine-readable data. The processing may comprise converting, by a processor, the machine-readable data from the first data format into a second data format suitable for use by the additive manufacturing apparatus to generate the three-dimensional object; and extracting metadata from the machine-readable data. The method may further include providing the processed data to an additive manufacturing apparatus for use in generating the three-dimensional object.

Abstract: A controller-implemented method of controlling a three dimensional (3D) printing process, comprises presenting printing options (20) of the 3D printing process at a user interface (16); accepting settings (22) from the user interface (16) based on the presented printing options (20); determining a printing instruction (24) based on the settings (22), the printing instruction (24) to be used to manufacture a three-dimensional (3D) object; and determining a post-processing instruction (26) based on the settings (22), the post-processing instruction (26) to be used in post-processing the 3D object.

Abstract: A method of forming a three-dimensional object includes detecting, with a thermographic camera, a temperature of a control point within at least one zone of the build material bed, and adjusting a power level supplied to at least one of the lamps of the array of lamps if the detected temperature of the control point of the at least one zone of the build material bed is not equal to a set temperature.

Abstract: In one example, an additive manufacturing system includes a processing system to obtain characteristic data including conditions under which a heat reservoir may be added close to a portion of the object, based on the characteristic data, add sacrificial structure data to the three-dimensional object data for a sacrificial heat reservoir structure close to a portion of the object and not connected to the object, and generate multiple slice images from the three-dimensional object data including the sacrificial structure data.

Abstract: According to an example, a printer may include a warming device to apply energy onto a region of a plurality of regions of a layer of build materials. The printer may also include a controller that may calculate, based upon the region upon which the warming device is to apply energy, an energy curve to be applied to the warming device between occurrences of a plurality of events, in which the energy curve defines timings and levels at which the warming device is to be operated between occurrences of the plurality of events. The controller may also control the warming device to be operated to apply energy onto the region according to the calculated energy curve.

Abstract: According to an example, a computing apparatus may include a processing device and a machine readable storage medium on which is stored instructions that when executed by the processing device, cause the processing device to access, from a sensing device, information pertaining to formation of a part of a 3D object in a layer of build materials upon which fusing agent droplets have been or are to be selectively deposited. The instructions may also cause the processing device to predict, based upon the accessed information, a quality of the part and output an indication of the predicted quality of the part.

Abstract: In one example, an apparatus for generating a three-dimensional object includes an energy source to apply energy to a layer of build material to cause a first portion of the layer to coalesce and solidify, an agent distributor to selectively deliver a cooling agent onto a second portion of the layer, and a controller to control the energy source to apply energy to the layer to cause the first portion to coalesce and solidify in a first pattern and to control the agent distributor to selectively deliver the cooling agent onto the second portion of the layer in a second pattern independent of the first pattern.

Abstract: In an example, a method includes measuring the temperature of a fused region and the temperature of an unfused region of a first layer of build material; determining a preheating setting for a subsequent layer of build material in response to the measured temperature of the unfused region of the first layer; determining a print instruction for applying print agent to the subsequent layer of build material, wherein the application of print agent prescribed by the print instruction for the subsequent layer to cause the temperature of the preheated build material to be a predetermined temperature prior to fusion in response to the measured temperature of the fused region of the first layer; forming the subsequent layer of build material; preheating the subsequent layer of build material in accordance with the preheating setting; and selectively applying the print agent onto the subsequent layer based on the print instruction.

Abstract: There is disclosed additive manufacturing apparatus (10), (22), (34) comprising: a heater (18), (36) to direct radiant heat onto an irradiation region (20) of a build platform (12), at least part of the heater (18), (36) being moveable to cause the irradiation region (20) to traverse over the build platform (12); a coating module (14) moveable relative the heater (18), (36) to traverse the build platform (12) to apply a build material onto the build platform (12); and a print module (16) moveable relative the heater (18), (36) to traverse the build platform (12) to selectively eject a print agent onto the build material.

Abstract: In one example, a system for heating lamp calibration can include a plurality of heating lamps over a print bed to heat the print bed over a period of time, a thermal imaging sensor to capture images of the print bed over the period of time, and a computing device coupled to the thermal imaging sensor to determine a surface flux delivered to each of a plurality of zones of the print bed over the period of time and calibrate a heating lamp of the plurality of heating lamps based on a corresponding contribution to the surface flux.

Abstract: In an example, a method includes forming, at an additive manufacturing apparatus, a first layer of build material to be processed in the generation of an object. A print agent is selectively applied onto the first layer based on a first print instruction associated with the first layer. Energy is applied to the first layer to cause fusion in a region of the first layer. The method further comprises: measuring the temperature of the first layer at a plurality of locations to form a measured temperature distribution profile; comparing the measured temperature distribution profile against a predicted temperature distribution profile to generate a difference; and correcting a temperature distribution profile of a subsequent layer of the build material following fusion of the subsequent layer based on the difference by modifying a second print instruction associated with the subsequent layer.

Abstract: Measures for use in an additive manufacturing system. A thermal camera measures temperatures of a printbed area of the system at a first time and a second, subsequent time during additive manufacture of an object in the printbed area. A controller receives, from the thermal camera, temperature information associated with the measured temperatures at the first time and the second time and processes the received temperature information to determine a first position of a moving part of the system at the first time and a second position of the moving part at the second time. In response to the processing indicating that the moving part has not moved by a sufficient amount between the first time and the second time, the controller determines that the moving part is operating abnormally.