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: A three-dimensional printing build material composition includes a polymer particle, and a radiation absorbing additive mixed with the polymer particle. The radiation absorbing additive has a particle size ranging from about 1 ?m to about 100 ?m, and the radiation absorbing additive is to absorb incident radiation having wavelengths ranging from 700 nm to 10 ?m.

Abstract: The present disclosure is drawn material sets, coalescent fluids, and 3-dimensional printing systems. An example material set can include an amorphous polymer powder having an average particle size from 1 micron to 300 microns, and a coalescent fluid including a viscosity reducing agent.

Abstract: An example of a fusing agent includes a metal bis(dithiolene) complex, a thiol surfactant, a polar aprotic solvent, and a balance of water. In an example of a method of making the fusing agent, the metal bis(dithiolene) complex is exposed to an aqueous solution including a reducing agent and a thiol surfactant to form a reduced metal bis(dithiolene) complex and to dissolve the reduced metal bis(dithiolene) complex in the aqueous solution. The aqueous solution is incorporated into a vehicle including a water soluble organic solvent and an additive selected from the group consisting of an emulsifier, a surface tension reduction agent, a wetting agent, a scale inhibitor, an anti-deceleration agent, a chelating agent, an antimicrobial agent, and a combination thereof. The fusing agent may be utilized in a three-dimensional printing method and/or incorporated into a three-dimensional printing system.

Abstract: In an example, a composition for three-dimensional (3D) printing includes a polymer build material and a non-conductive fusing agent dispensable onto the polymer build material to form a polymer-fusing agent composite portion when heated to a sintering temperature, a conductive agent dispensable onto on the polymer build material to form a polymer-conductive agent composite portion when heated at least to the sintering temperature, the conductive agent comprising: at least one conductive particulate present in an amount of from about 10% to about 60% of a total weight of the conductive agent; at least one co-solvent present in an amount of from about 10% to about 50% of a total weight of the conductive agent; and an additive present in an amount of from about 0% to about 10% of a total weight of the conductive agent.

Abstract: In an example of a three-dimensional (3D) printing method, a polymeric build material is applied. A fusing agent is selectively applied on at least a portion of the polymeric build material. A mechanical tailoring agent is selectively applied on at least a region of the portion. The polymeric build material is exposed to radiation, thereby fusing the at least the portion of the polymeric build material in contact with the fusing agent to form a layer. The mechanical tailoring agent forms a composite layer in the at least the region, and the composite layer has a different mechanical property than that of an area of the layer not in contact with the mechanical tailoring agent.

Abstract: Apparatus and methods for making metal-connected particle articles. A metal containing fluid is selectively applied to a layer of particles. The metal in the fluid is used to form metal connections between particles. The metal connections are formed at temperatures below the sintering temperature of the particles in the layer of particles.

Abstract: Apparatus and methods for making metal-connected particle articles. A metal containing fluid is selectively applied to a layer of particles. The metal in the fluid is used to form metal connections between particles, The metal connections are formed at temperatures below the sintering temperature of the particles in the layer of particles.

Abstract: Apparatus and methods for making metal-connected particle articles. A metal containing fluid is selectively applied to a layer of particles. The metal in the fluid is used to form metal connections between particles. The metal connections are formed at temperatures below the sintering temperature of the particles in the layer of particles.

Abstract: In a three-dimensional printing method example, a metallic build material is applied. A positive masking agent is selectively applied on at least a portion of the metallic build material. The positive masking agent includes a radiation absorption amplifier that is compatible with the metallic build material. The metallic build material is exposed to radiation from a spatially broad, high energy light source to melt the portion of the metallic build material in contact with the positive masking agent to form a layer. The radiation absorption amplifier i) has an absorbance for the radiation that is higher than an absorbance for the radiation of the metallic build material, or ii) modifies a surface topography of the at least the portion of the metallic build material to reduce specular reflection of the radiation off of the at least the portion of the metallic build material, or both i) and ii).

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: An example of a fusing agent includes a metal bis(dithiolene) complex, a thiol surfactant, a polar aprotic solvent, and a balance of water. In an example of a method of making the fusing agent, the metal bis(dithiolene) complex is exposed to an aqueous solution including a reducing agent and a thiol surfactant to form a reduced metal bis(dithiolene) complex and to dissolve the reduced metal bis(dithiolene) complex in the aqueous solution. The aqueous solution is incorporated into a vehicle including a water soluble organic solvent and an additive selected from the group consisting of an emulsifier, a surface tension reduction agent, a wetting agent, a scale inhibitor, an anti-deceleration agent, a chelating agent, an antimicrobial agent, and a combination thereof. The fusing agent may be utilized in a three-dimensional printing method and/or incorporated into a three-dimensional printing system.

Abstract: An example of a fusing agent includes a tetraphenyldiamine-based dye, alkyldiphenyloxide disulfonate, 1-methyl-2-pyrrolidone, and a balance of water. The fusing agent excludes a strong reducing species. The fusing agent may be incorporated into a three-dimensional printing method or a three-dimensional printing system. In an example of the three-dimensional printing method, a polymeric or polymeric composite build material is applied. The fusing agent is selectively applied on at least a portion of the polymeric or polymeric composite build material. The polymeric or polymeric composite build material is exposed to electromagnetic radiation to fuse the portion of the polymeric or polymeric composite build material in contact with the fusing agent to form a layer.

Abstract: In an example of a three-dimensional (3D) printing method, a polymeric build material is applied. A fusing agent is selectively applied on at least a portion of the polymeric build material. A mechanical tailoring agent is selectively applied on at least a region of the portion. The polymeric build material is exposed to radiation, thereby fusing the at least the portion of the polymeric build material in contact with the fusing agent to form a layer. The mechanical tailoring agent forms a composite layer in the at least the region, and the composite layer has a different mechanical property than that of an area of the layer not in contact with the mechanical tailoring agent.

Abstract: The present disclosure is drawn material sets, coalescent fluids, and 3-dimensional printing systems. An example material set can include an amorphous polymer powder having an average particle size from 1 micron to 300 microns, and a coalescent fluid including a viscosity reducing agent.

Abstract: In an example of a three-dimensional (3D) printing method, a crystalline or semi-crystalline build material is applied. A temperature of the crystalline or semi-crystalline build material is maintained within 100° C. below a melting point of the crystalline or semi-crystalline build material. A melt flow property reduction agent is applied to at least a portion of the crystalline or semi-crystalline build material, and the at least the portion of the crystalline or semi-crystalline build material in contact with the melt flow property reduction agent melts or coalesces at the temperature.

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.

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: The present disclosure is drawn to coalescent inks and material sets, such as for 3D printing. In one example, the coalescent ink can include a conjugated polymer, a colorant imparting a visible color to the coalescent ink, and an ink vehicle comprising a high boiling point co-solvent having a boiling point of 250° C. or greater. The high boiling point co-solvent can be present in an amount from about 1 wt % to about 4 wt % with respect to the coalescent ink.

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.