Abstract: In one example, a device for printing a three-dimensional object is described. The device may include at least one material application unit to deposit at least one material for a voxel of the three-dimensional object, a vertical cavity surface emitting laser array comprising a plurality of vertical cavity surface emitting lasers, the plurality of vertical cavity surface emitting lasers including a first vertical cavity surface emitting laser to operate at a first wavelength and a second vertical cavity surface emitting laser to operate at a second wavelength, and a processor to control a deposition of the at least one material for the voxel via the at least one material application unit and to control an application of electromagnetic energy via at least one of the plurality of vertical cavity surface emitting lasers to the voxel to alter at least one property of the at least one material.

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 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: An example of a three-dimensional (3D) printing kit includes a build material composition, an epoxy agent to be applied to at least a portion of the build material composition during 3D printing, and a fusing agent to be applied to the at least the portion of the build material composition during 3D printing. The build material composition includes a polyamide having an amino functional group. The epoxy agent includes an epoxy having an epoxide functional group to react with the amino functional group of the polyamide in the at least the portion. The fusing agent includes an energy absorber.

Abstract: In an example method for forming three-dimensional (3D) printed electronic parts, a build material is applied. An electronic agent is selectively applied in a plurality of passes on a portion of the build material. A fusing agent is also selectively applied on the portion of the build material. The build material is exposed to radiation in a plurality of heating events. During at least one of the plurality of heating events, the portion of the build material in contact with the fusing agent fuses to form a region of a layer. The region of the layer exhibits an electronic property. An order of the plurality of passes, the selective application of the fusing agent, and the plurality of heating events is controlled to control a mechanical property of the layer and the electronic property of the region.

Abstract: The present disclosure is drawn to a three-dimensional printing kit and can include a particulate build material including from about 80 wt % to about 100 wt % metal particles, and a binding agent including water, from about 0.01 wt % to about 5 wt % organic compounds, and from about 20 wt % to about 60 wt % copper nitrate.

Abstract: A three-dimensional (3D) printing method includes applying a build material composition having a polymer particle and a radiation absorbing additive mixed with the polymer particle, the radiation absorbing additive being selected from the group consisting of inorganic near-infrared absorbers, organic near-infrared absorbers, and combinations thereof. The build material composition is preheated to a temperature below the melting temperature of the polymer particle by exposing the build material composition to radiation, the radiation absorbing additive increasing radiation absorption and accelerating the pre-heating of the build material composition. A fusing agent is selectively applied on at least a portion of the build material composition. The method further includes exposing the build material composition to radiation, whereby at least the polymer particle in the at least the portion of the build material composition in contact with the fusing agent at least partially fuses.

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: The present disclosure is drawn to multi-fluid kits for three-dimensional to printing, three-dimensional printing kits, and methods of making three-dimensional printed articles. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent, a first reactive agent, and a second reactive agent. The fusing agent can include water and a radiation absorber. The first reactive agent can include a first liquid vehicle and an epoxy compound having multiple epoxide groups. The second reactive agent can include a second liquid vehicle and an amine compound having multiple amino groups.

Abstract: A three-dimensional (3D) printing system may include a build volume, a slurry reservoir to contain a slurry of build material and liquid, and a slurry dispenser to receive the slurry from the slurry reservoir and movable in a direction across the build volume to dispense slurry across the build volume.

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: An example system includes a three-dimensional (3D) printer to generate a 3D object and a surface feature formation arrangement to receive the 3D object. The 3D object has at least one surface with a layer of at least partly uncured material. The surface feature formation arrangement includes a controller and a heat source. The controller is to operate the heat source to selectively apply heat to the at least one surface of the 3D object. The heat from the heat source is to transform the at least partly uncured material to form a selected feature on the at least one surface.

Abstract: In an example method for forming three-dimensional (3D) printed electronic parts, a build material is applied. An electronic agent is selectively applied in a plurality of passes on a portion of the build material. A fusing agent is also selectively applied on the portion of the build material. The build material is exposed to radiation in a plurality of heating events. During at least one of the plurality of heating events, the portion of the build material in contact with the fusing agent fuses to form a region of a layer. The region of the layer exhibits an electronic property. An order of the plurality of passes, the selective application of the fusing agent, and the plurality of heating events is controlled to control a mechanical property of the layer and the electronic property of the region.

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: In an example of a method for forming three-dimensional (3D) printed electronics, a build material is applied. A fusing agent is selectively applied on at least a portion of the build material. The build material is exposed to radiation and the portion of the build material in contact with the fusing agent fuses to form a layer. An electronic agent is selectively applied on at least a portion of the layer, which imparts an electronic property to the at least the portion of the layer.

Abstract: Some examples include an additive manufacturing system including a processor and a memory to store instructions. The instructions cause the processor to generate print data from received data related to a three-dimensional build object. The generated print data includes defined print data to dispensing a first agent at a build area of a build material layer, defined print data to selectively dispensing a second agent at a component receiving area within the build area of the build material layer, the second agent to locally reduce a viscosity of the build material at the component receiving area to a viscous state, and defined print data to position a component within the component receiving area at a time of the component receiving area being in a viscous state.

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: The present disclosure is drawn to multi-fluid kits for three-dimensional to printing, three-dimensional printing kits, and methods of making three-dimensional printed articles. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent, a first reactive agent, and a second reactive agent. The fusing agent can include water and a radiation absorber. The first reactive agent can include a first liquid vehicle and an epoxy compound having multiple epoxide groups. The second reactive agent can include a second liquid vehicle and an amine compound having multiple amino groups.

Abstract: Some examples include an additive manufacturing system including a processor and a memory to store instructions. The instructions cause the processor to generate print data from received data related to a three-dimensional build object. The generated print data includes defined print data to dispensing a first agent at a build area of a build material layer, defined print data to selectively dispensing a second agent at a component receiving area within the build area of the build material layer, the second agent to locally reduce a viscosity of the build material at the component receiving area to a viscous state, and defined print data to position a component within the component receiving area at a time of the component receiving area being in a viscous state.

Abstract: According to an example, a composition may include a high melt temperature build material in the form of a powder; a first low melt temperature binder in the form of a powder; and a second low melt temperature binder in the form of a powder; and in which the first low melt temperature binder melts at a temperature that is different from the second low melt temperature binder.