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: A 3D printing kit can include a powder bed material comprising from about 80 wt % to 100 wt % polymer particles, a fusing agent to selectively apply to the powder bed material, and a hardener to selectively apply to the powder bed material. The polymeric particles can include a polyalkylene backbone with both ethylene and propylene polymerized monomeric units with from 2 mol % to 15 mol % of the polymerized monomeric units include a grafted side chain having an epoxide moiety. The fusing agent can include water and a radiation absorber that absorbs electromagnetic energy and converts the electromagnetic energy to heat. The hardener can be present in the fusing agent or can be included in a hardening agent that is separate from the fusing agent.

Abstract: A particulate build material for three-dimensional printing can include from about 80 wt % to 100 wt % polymer particles having an average particle size from about 10 ?m to about 125 ?m. The polymer particles can have a polyolefin polymer backbone with from about 90 mol % to 100 mol % polypropylene polymeric units and from 0 mol % to about 10 mol % polyethylene polymeric units. The polymer particles can further include a crosslinkable component in the form of a maleic anhydride-containing side chain appended to the polyolefin polymer backbone, a thiol-containing side chain appended to the polyolefin polymer backbone, a glycidyl polyhedral oligomeric silsesquioxane compounded with the polyolefin polymer backbone, or a combination thereof.

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: 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: 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: 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: The present disclosure relates to a method of manufacturing a 3D printed object. The method comprises selectively applying a fusing agent onto powder bed material; and exposing at least part of the powder bed material to radiation to fuse at least part of the powder bed material to form a layer of the 3D printed object. The fusing agent and/or a detailing agent is selectively applied to the powder bed material in a predetermined arrangement to form a porous region in the 3D printed object. The 3D printed object is then treated with a modifying agent, such that the modifying agent at least partially penetrates the porous region of the 3D printed object.

Abstract: The present disclosure is drawn to multi-fluid kits for three-dimensional 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 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 three-dimensional printing method can include iteratively applying polymer build material as individual layers; based on a three-dimensional object model, selectively jetting an electromagnetic radiation absorber and a translucency-modulating plasticizer onto individual layers of the polymer build material; and exposing the powder bed to electromagnetic energy to selectively fuse portions of individual layers of the polymer build material together to form a three-dimensional object. The polymer build material can include from about 60 wt % to 100 wt % polymeric particles having an average particle size from about 10 ?m to about 150 ?m and a degree of crystallinity from about 2% to about 60%, to a powder bed. At the locations where the polymer build material includes jetted translucency-modulating plasticizer, the three-dimensional object can exhibit an optical transmittance from about 5% to about 80%.

Abstract: In an example of a method for three-dimensional (3D) printing, a build material composition is applied to form a build material layer. The build material composition includes a polyamide. The polyamide is selectively melted, based on a 3D object model, in at least a portion of the build material layer to form a molten portion including molten polyamide. An epoxy agent is selectively applied, based on the 3D object model, on the molten portion of the build material layer. The epoxy agent includes a polyfunctional epoxy, which crosslinks the molten polyamide in the molten portion.

Abstract: Fusing agent(s) are described herein. In an example, a fusing agent can comprise a metal bis(dithiolene) complex, at least one electron donor compound, a polar aprotic solvent, and water. In some examples, the at least one electron donor compound can comprise at least one hindered amine light stabilizer compound. In some examples, the polar aprotic solvent can be selected from the group consisting of 1-methyl-2-pyrrolidone, 2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and a combination thereof.

Abstract: A 3D printing kit can include a powder bed material comprising from about 80 wt % to 100 wt % polymer particles, a fusing agent to selectively apply to the powder bed material, and a hardener to selectively apply to the powder bed material. The polymeric particles can include a polyalkylene backbone with both ethylene and propylene polymerized monomeric units with from 2 mol % to 15 mol % of the polymerized monomeric units include a grafted side chain having an epoxide moiety. The fusing agent can include water and a radiation absorber that absorbs electromagnetic energy and converts the electromagnetic energy to heat. The hardener can be present in the fusing agent or can be included in a hardening agent that is separate from the fusing agent.

Abstract: The present disclosure relates to a three-dimensional (3D) printing materials kit comprising: a first tailoring agent comprising at least one crosslinking agent; a second tailoring agent comprising at least one plasticizer, and a fusing agent. The present disclosure also relates to a printed structure comprising regions of relatively higher ductility and regions of relatively lower ductility. The regions of relatively higher ductility can be interspersed by the regions of relatively lower ductility, and the regions of relatively lower ductility can be formed from a crosslinked polymer and/or a polymer composition comprising a reinforcing filler, and/or the regions of relatively higher ductility can be formed from a polymer composition comprising a plasticizer. The present disclosure also relates to a method of three dimensional printing (3D) that can be used to print a 3D printed object comprising the printed structure described above.

Abstract: The present disclosure is drawn to multi-fluid kits for three-dimensional 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: 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 of a method for three-dimensional (3D) printing, a build material composition is applied to form a build material layer. The build material composition includes a polyamide. The polyamide is selectively melted, based on a 3D object model, in at least a portion of the build material layer to form a molten portion including molten polyamide. An epoxy agent is selectively applied, based on the 3D object model, on the molten portion of the build material layer. The epoxy agent includes a polyfunctional epoxy, which crosslinks the molten polyamide in the molten portion.

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: Examples of binder agents for a three-dimensional (3D) printing process are disclosed. In an example, the binder agent includes copper nanoparticles and a liquid vehicle. In this example, the liquid vehicle includes an antioxidant, polyethylene glycol hexadecyl ether, and a balance of water. Another example of the binder agent includes stainless steel nanoparticles and a liquid vehicle. In this example, the liquid vehicle includes polyethylene glycol hexadecyl ether, and a balance of water. Still another example of the binder agent includes nickel nanoparticles and a liquid vehicle. The liquid vehicle includes an antioxidant; a symmetric triblock copolymer including poly(ethylene oxide) and poly(propylene oxide), and a balance of water.