Abstract: In one example, an additive manufacturing process includes: making an object slice by slice, including dispensing a first quantity of each of multiple liquid functional agents on to a layer of fusable build material and then irradiating the layer of build material; while making the object, identifying a deviant region in a slice; and dispensing a second quantity different from the first quantity of at least one of the functional agents into a location corresponding to the deviant region.

Abstract: An example of a fusing agent includes a metal bis(dithiolene) salt, a polar aprotic solvent, and a balance of water. An example of a method for making an example of the fusing agent includes adding a metal bis(dithiolene) salt into a liquid vehicle including at least a polar aprotic solvent and water.

Abstract: In one example In accordance with the present disclosure, a fluid ejection device is described. The fluid ejection device Includes a number of nozzles to eject fluid. Each nozzle Includes multiple firing chambers to hold fluid. The multiple firing chambers are separated: by a chamber partition. Each nozzle also includes a shared nozzle orifice in a substrate through which to dispense fluid. Each nozzle also Includes multiple ejectors, at least one ejector disposed in each firing chamber, in a common channel of the nozzle, fluid from the multiple firing chambers Is mixed, A height of the common channel is defined by the substrate and the chamber partition and is less than a width of the shared nozzle orifice.

Abstract: According to an example, an apparatus may include an agent delivery device to selectively deliver an agent onto a layer of build material particles. The apparatus may also include an energy source to apply energy onto the layer of build material particles to selectively fuse the build material particles in the layer based upon the locations at which the agent was delivered and a chamber formed of a plurality of walls, in which the agent delivery device and the energy source are housed inside the chamber. The apparatus may further include a vapor source to supply vapor into the chamber to wet the build material particles inside the chamber.

Abstract: The present disclosure is drawn to material sets for 3D printing and methods of 3D printing. The material set can include a coalescent an organic-soluble near-infrared dye having a peak absorption wavelength from 800 nm to 1400 nm. The coalescent ink can also include water and an organic co-solvent. The material set can also include a particulate polymer formulated to coalesce when contacted by the coalescent ink and irradiated by a near-infrared energy having the peak absorption wavelength.

Abstract: According to an example, a three-dimensional (3D) printer may include a first delivery device to selectively deposit a fusing agent onto a layer of build materials and a second delivery device to deposit coolant droplets at tuned drop weights onto the layer of build materials. The 3D printer may also include a controller to control the second delivery device to selectively deposit the coolant droplets at the tuned drop weights onto selected areas of the build material layer, in which the drop weights of the selectively deposited coolant droplets are tuned to provide a thermal balance between multiple areas of the build material layer during application of fusing radiation onto the build material layer.

Abstract: In one example, an additive manufacturing process includes: making an object slice by slice, including dispensing a first quantity of each of multiple liquid functional agents on to a layer of fusable build material and then irradiating the layer of build material; while making the object, identifying a deviant region in a slice; and dispensing a second quantity different from the first quantity of at least one of the functional agents into a location corresponding to the deviant region.

Abstract: In some examples, a request to print a first three-dimensional (3D) part is received. In response to determining that the first 3D part is not similar to any 3D part referred to by an information base, a representation of the first 3D part is extracted, an indication to conduct an operation to produce a design rule for the first 3D part is sent. In response to determining that the first 3D part is similar to a matching 3D part referred to by the information base, a design rule for the matching 3D part is retrieved to print the first 3D part, where the design rule for the matching 3D part specifies a dependency of a property of the matching 3D part on an aspect associated with printing the matching 3D part.

Abstract: According to examples, an apparatus may include a printhead assembly containing a housing supporting a printhead. The printhead may have nozzles that are to fire droplets of a functional agent onto a layer of build material particles along respective flight paths to form sections of a 3D object from the build material particles, an array of light emission devices to direct respective light beams in the respective flight paths, and an array of photon detectors to detect respective light beams directed from a light source of the array of light emission devices, the light emission devices and the photon detectors being supported on the housing. The apparatus may also include a controller to determine whether any of the nozzles is operating improperly based upon whether the photon detectors detected the light beams and to output an instruction regarding an improperly operating nozzle in response to a determination that the nozzle is operating improperly.

Abstract: According to examples, an apparatus includes a processor and a memory on which is stored machine readable instructions. The instructions may cause the processor to identify an intended surface property level for a surface of a three-dimensional (3D) object, determine an amount of radiation to be applied as a flash of radiation onto the surface to obtain the intended surface property level, and output the determined amount of radiation to be applied as a flash of radiation, in which a radiation source is to flash apply the determined amount of radiation onto the surface of the 3D object.

Abstract: A system for forming a multiple layer object, the system including: a spreader to form a layer of polymer particles, the polymer particles having a melting temperature (Tm) of at least 250° C.; a fluid ejection head to selectively deposit a first fusing agent on a first portion of the layer and selectively deposit a second fusing agent on a second portion of the layer, wherein the fluid ejection head does not deposit the fusing agent on a third portion of the layer; and a heat source to heat the first portion and second portion, wherein the first portion is part of the multiple layer object and the second portion is not part of the multiple layer object and the second portion raises a temperature of polymer particles in a subsequent layer.

Abstract: In an example, a method includes receiving object model data describing at least a portion of an object to be generated by additive manufacturing. Object generation instructions for generating the object in its entirety may be derived based on the object model data. Where it is determined that the object model data comprises a data deficiency for deriving the object generation instructions, at least one attribute for the object may be inferred and object generation instructions may be derived based on the object model data and the inferred attribute.

Abstract: According to examples, an object may include a shell including a polymer binder and build material powder; and a core at least partially encompassed by the shell, the core including build material powder and a metal nanoparticle binder.

Abstract: In an example, a three-dimensional (3D) printed part comprises a plurality of fused build material layers including exterior layers and interior layers. At least some of the interior layers include a composite portion having a miscible solid physically bonded to an amide functionality or an amine functionality of the build material. The miscible solid is a solid at a room temperature ranging from about 18° C. to about 25° C.

Abstract: According to an example, a three-dimensional (3D) printer may include a delivery device to deposit a light absorbing agent onto selected areas of a layer of build material particles, in which the light absorbing agent absorbs light having wavelengths that are around the ultraviolet wavelength range. The 3D printer may also include a light source to apply light onto the selectively deposited light absorbing agent and the layer of the build material particles, in which the light absorbing agent absorbs light around the ultraviolet wavelength range from the applied light and becomes heated to a temperature that causes the build material particles upon which the light absorbing agent has been deposited to melt and to fuse together following cessation of the application of the light.

Abstract: A device includes a carriage movable relative to a build pad along a bi-directional travel path and supporting at least a radiation source and an applicator to selectively apply a plurality of fluid agents, including first fluid agents to affect a first material property. A timing and order of operation of the radiation source and the applicator, with the carriage, is to maintain first and second portions of a 3D object under formation within at least one selectable temperature range despite a first total volume of the first fluid agents for application onto the first portion of the 3D object being substantially greater than a second total volume of second fluid agents for application onto the second portion of the 3D object.

Abstract: A device includes a coater, a dispenser, and a treatment portion. The coater is to coat, layer-by-layer, a build material relative to a build pad to form a 3D object. The dispenser is to at least dispense a fluid including a first at least potentially electrically conductive material. In at least some selected locations of an external surface of the 3D object. The treatment portion is to treat the 3D object to substantially increase electrically conductivity on the external surface of the 3D object at the at least some selected locations.

Abstract: A Region Merging image segmentation algorithm based on boundary extraction is disclosed, comprising the steps of calculating a gradient image, extracting a boundary and carrying out initial segmentation and Region Merging, wherein each pixel is regarded as one region when initial segmentation is not conducted. In the Region Merging process, the portion of the common boundary of two adjacent regions that lies on the boundary image is taken as the merging cost, the regions are merged according to the ascending order of the mean gradient value inside the region, and a texture difference evaluation mechanism is introduced to reduce the wrong segmentation. The algorithm solves the problems of the other current segmentation algorithms, such as over-segmentation, easy to be influenced by noise and illumination, large in computation and memory consumption, in need of a large number of samples being marked manually and the like.

Abstract: In some examples, an interaction module of a three-dimensional (3D) printer can include an interaction sub-module including a coupler, where the coupler is to connect to a tool, a first actuator to move the coupler in a first direction, and a second actuator to move the coupler in a second direction, and an analytics system to analyze the coupler and the tool during an interaction with a 3D object of the 3D printer, where the tool of the coupler is to interact with the 3D object of the 3D printer during a 3D print job.

Abstract: An agent distributor may be to selectively deliver agent at a first contone density and at a second contone density different from the first contone density respectively onto an interior portion and a surface portion of successive layers of build material in respective first and second patterns in accordance with data representing a three-dimensional object to be generated, so that the build material is to solidify to form slices of the three-dimensional object in accordance with the first and second patterns, and so that the three-dimensional object is to achieve a target surface roughness as a result of the second contone density of the second pattern.