Abstract: In an example of a method for three-dimensional (3D) printing, a polymeric build material is applied to form a build material layer. A fusing agent is selectively applied, based on a 3D object model, onto the build material layer to form a patterned portion. A hydrophobic agent is selectively applied, based on the 3D object model, onto at least a portion of the patterned portion. The hydrophobic agent includes a lipophilic phase discontinuously dispersed within an aqueous phase by a surfactant, wherein the lipophilic phase includes an organosilane having a central silicon atom coupled to a C6 to C24 aliphatic or alicyclic hydrocarbon and multiple hydrolyzable groups, wherein the organosilane is present in the hydrophobic agent at from about 1 wt % to about 20 wt %. The build material layer is exposed to energy to selectively coalesce the patterned portion and form a 3D object layer having a hydrophobic portion.

Abstract: The present disclosure includes a multi-fluid kit for three-dimensional printing. The multi-fluid kit can include a fusing agent comprising water and a radiation absorber that absorbs radiation energy and converts the radiation energy to heat, an acidic agent having a pH from about pH 1 to about pH 6.9 that includes water and an acidic component, and a pore-promoting agent including water and a pore-promoting compound. The pore-promoting compound can chemically react with the acidic component to generate a gas, and can be selected from sodium bicarbonate, potassium bicarbonate, or a combination thereof.

Abstract: The present disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and systems for three-dimensional printing. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent, a solubilizing agent, and a detailing agent. The fusing agent can include water and an electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation energy and convert the radiation energy to heat. The solubilizing agent can include benzyl alcohol, an organic cosolvent, and water. The detailing agent can include a detailing compound.

Abstract: A three-dimensional printing kit can include a build material with from about 80 wt % to 100 wt % polymeric particles having a D50 particle size from about 10 ?m to about 150 ?m, and a fusing agent including from about 0.5 wt % to about 20 wt % avobenzone particles dispersed in an aqueous liquid vehicle based on a total weight of the fusing agent.

Abstract: A multi-fluid kit for three-dimensional printing can include a fusing agent and a detailing agent. The fusing agent can include water and a radiation absorber. The radiation absorber absorbs radiation energy and converts the radiation energy to heat. The detailing agent includes a lipophilic phase discontinuously dispersed within an aqueous phase by a surfactant. The lipophilic phase includes an organosilane having a central silicon atom coupled to a C6 to C24 aliphatic or alicyclic hydrocarbon and multiple hydrolyzable groups. The organosilane is present in the detailing agent at from about 1 wt % to about 20 wt %.

Abstract: The present disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and methods of three-dimensional printing. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent and a ductility agent. The fusing agent can include water and electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation energy and convert the radiation energy to heat. The ductility agent can include water, a water-soluble pore-generating compound that chemically reacts at an elevated temperature to generate a gas, and a plasticizer. The plasticizer can have formula (I) wherein n is an integer ranging from 3 to 8; or formula (II) wherein m is an integer ranging from 3 to 8.

Abstract: In an example of a surface treatment method, a three-dimensionally printed polyamide object is used. In the surface treatment method, the three-dimensionally printed polyamide object is first exposed to benzyl alcohol. In the surface treatment method, the three-dimensionally printed polyamide object is exposed to microwave irradiation after the benzyl alcohol exposure.

Abstract: An example of a kit for three-dimensional (3D) printing includes an ultraviolet (UV) light fusing agent. The ultraviolet (UV) light fusing agent includes an aqueous vehicle; and a functionalized benzophenone that is at least partially soluble in the aqueous vehicle, the functionalized benzophenone having absorption at wavelengths ranging from about 340 nm to about 405 nm.

Abstract: An example of a multi-fluid kit for three-dimensional (3D) printing includes a fusing agent and a surface treating agent. The fusing agent includes an electromagnetic radiation absorber and a first aqueous vehicle. The surface treating agent includes a second aqueous vehicle, a surfactant, and benzyl alcohol dissolved in the second aqueous vehicle.

Abstract: The present disclosure describes materials, methods, and systems for three-dimensional printing. In one example, a three-dimensional printing kit can include a fusing agent and a microbe-inhibiting agent. The fusing agent can include water and an electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation and convert the radiation energy to heat. The microbe-inhibiting agent can include a liquid vehicle and a metal bis(dithiolene) complex. The disclosure also describes methods of three-dimensional printing that utilize a metal-containing microbe-inhibiting material, which can be a metal bis(dithiolene) complex or other materials.

Abstract: The present disclosure includes a three-dimensional printing kit having a fusing agent with from about 75 wt % to about 99 wt % water, and from about 0.1 wt % to about 15 wt % radiation absorber. The three-dimensional printing kit can further include a polymeric build material including polyamide-12 particles, and a liquid oil comprising from about 50 wt % to 100 wt % of a long-chain molecule having a carbon chain of about C12 to about C100.

Abstract: An example of a kit for three-dimensional (3D) printing includes an ultraviolet (UV) light fusing agent. The ultraviolet (UV) light fusing agent includes an aqueous vehicle and a B vitamin or a B vitamin derivative present in an amount that dissolves in the aqueous vehicle. The aqueous vehicle includes a co-solvent, a surfactant, and water. The B vitamin or the B vitamin derivative has absorption at wavelengths ranging from about 340 nm to about 415 nm.

Abstract: A method of recovering fluoropolymer from a three-dimensional printed object can include dissolving a fluoropolymer of a three-dimensional printed object in a fluoropolymer-dissolving solvent to generate dissolved fluoropolymer from the three-dimensional object, wherein the three-dimensional printed object includes from about 0.1 wt % to about 10 wt % particulate fusing compound and from about 90 wt % to about 99.9 wt % fluoropolymer. The method can further include separating the particulate fusing compound from the fluoropolymer-dissolving solvent and the dissolved fluoropolymer, and evaporating the fluoropolymer-dissolving solvent from the dissolved fluoropolymer.

Abstract: An example of a kit for three-dimensional (3D) printing includes an ultraviolet (UV) light fusing agent and a detailing agent. The UV light fusing agent including an aqueous vehicle and a plasmonic metal nanoparticle that i) provides absorption enhancement at radiation wavelengths ranging from about 340 nm to about 450 nm, and ii) is present in an amount up to 2 wt% based on a total weight of the UV light fusing agent. The detailing agent includes a surfactant, a co-solvent, and water.

Abstract: A three-dimensional printing kit can include a build material and a fusing agent. The build material can include from about 80 wt % to 100 wt % polymeric particles having a D50 particle size from about 10 ?m to about 150 ?m. The fusing agent can include an aqueous liquid vehicle and natural food-derived fusing compound dissolved or dispersed therein. The natural food-derived fusing compound can have an absorption peak from about 340 nm to about 780 nm.

Abstract: A method of recovering polyolefin polymer from a three-dimensional printed object can include dissolving a polyolefin polymer of a three-dimensional printed object in a polyolefin-dissolving solvent to generate dissolved polyolefin polymer from the three-dimensional object, wherein the three-dimensional printed object includes from about 0.1 wt % to about 10 wt% particulate fusing compound and from about 90 wt% to about 99.9 wt% polyolefin polymer. The method can further include separating the particulate fusing compound from the polyolefin-dissolving solvent and the dissolved polyolefin polymer, and evaporating the polyolefin-dissolving solvent from the dissolved polyolefin polymer.

Abstract: An example of an ultraviolet (UV) light fusing agent for three-dimensional (3D) printing includes a UV light absorber and a liquid vehicle. The UV light absorber consists of a fluorescent yellow dye. The liquid vehicle includes a surfactant, a co-solvent, and a balance of water. The UV light fusing agent is devoid of a saccharide.

Abstract: A three-dimensional printing kit can include a polymeric build material and a fusing agent. The polymeric build material can include polymer particles having a D50 particle size from about 2 ?m to about 150 ?m. The fusing agent can include an aqueous liquid vehicle including water and an organic co-solvent, a radiation absorber to generate heat from absorbed electromagnetic radiation, and from about 2 wt % to about 15 wt % of a carbamide-containing compound.

Abstract: In one example in accordance with the present disclosure, an additive manufacturing system is described. The additive manufacturing system includes a build material distributor to deposit powder build material on a surface and an agent distribution system to selectively deposit various colored fusing agents and an ultraviolet absorbing agent on the powder build material in a pattern of a layer of a three-dimensional (3D) object to be printed. An irradiation source selectively fuses powder build material with colored fusing agent disposed thereon. The additive manufacturing system also includes a controller. The controller, per location of the layer of the 3D object to be printed 1) determines an energy absorption at the location based on an absorptivity of colored fusing agents deposited at that location and 2) determines an additive manufacturing adjustment to be made at the location to bring the energy absorption at the location to a target level.

Abstract: This disclosure describes three-dimensional printing kits, methods, and systems for three-dimensional printing with phosphorescent pigments. In one example, a three-dimensional printing kit can include a powder bed material and a low-tint fusing agent. The powder bed material can include polymer particles and phosphorescent pigment particles mixed with the polymer particles. The low-tint fusing agent can include water and an electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation energy and convert the absorbed radiation energy to heat.