Abstract: A powder bed material can include from 80 wt % to 100 wt % metal particles having a D50 particle size distribution value from 4 ?m to 150 ?m. From 10 wt % to 100 wt % of the metal particles can be surface-activated metal particles having in intact inner volume and an outer volume with structural defects. The structural defects can exhibit an average surface grain density of 50,000 to 5,000,000 per mm2.

Abstract: The present disclosure is drawn to a material set including a powder bed material and a binder fluid. The powder bed material can be from 80 wt % to 100 wt % metal particles having a metal core and a thin metal layer on the core, and the metal particles having a D50 particle size distribution value ranging from 4 ?m to 150 ?m and the thin metal layer having an average thickness from 20 nm to 2 ?m. The binder fluid can adhere a first portion of the powder bed material relative to a second portion of the powder bed material not in contact with the binder fluid.

Abstract: Example post-print processing of three dimensional (3D) printed objects are disclosed. An example system includes an energy source to apply energy to a selected portion of an outer surface of a 3D printed object. The energy provided by the energy source is to cause a polymer of the selected portion to melt and reflow. The selected portion and a non-selected portion of the outer surface to form a pattern on the outer surface of the 3D printed object. A controller to direct the energy of the energy source to the selected portion of the outer surface.

Abstract: A 3D printer to additively manufacture a 3D object includes a coater, a dispenser, and an energy source. The coater is to coat a first material relative to a print bed to form a selectable number of first layers. The dispenser is to dispense a first fluid agent onto first selected locations of the first layers of the first material. The energy source is to cause fusing at the first selected locations. The dispenser is to also dispense a second fluid agent including a second material to form a selectable number of second layers of the second material at second selected locations on top of the selectable number of first layers. Each second selected location comprises at least some of the fused first selected locations.

Abstract: Example described herein include a three-dimensional printer a three-dimensional printing device that includes a fusible material applicator to apply a layer of fusible material, a inhibiting material applicator to apply a patterned layer of inhibiting material to establish exposed regions of the layer of fusible material and blocked regions of the layer of fusible material based on information corresponding to a three-dimensional model, and a photonic energy emitter to apply photonic energy to fuse the exposed regions of the layer of fusible material.

Abstract: At a print temperature, a layer (having a predetermined height) of metal build material particles is formed. Also at the print temperature, a fluid containing metal nanoparticles is selectively applied to at least a portion of the layer, and at a fluid loading that wets the portion through the predetermined height without saturating the portion. The metal nanoparticles are exposed to a sintering temperature that is higher than the print temperature and at least 500° below a melting point of the metal build material particles using a predetermined number of heating events taking place at a predetermined speed or for a predetermined time, and separated by a predetermined delay time, to bind the metal build material particles together to form a bound layer. A build material surface is cooled to or below the print temperature. The forming, selectively applying, exposing, and cooling are repeated to form a part precursor.

Abstract: According to an example, a green body may include from about 1 wt. % to about 20 wt. % of a metal nanoparticle binder and a build material powder, wherein the metal nanoparticle binder is selectively located within an area of the green body to impart a strength greater than about 3 MPa.

Abstract: According to examples, a brown body has from about 0.02 wt. % to about 10 wt. % of a metal nanoparticle binder, in which the metal nanoparticle binder is selectively located within an area of the brown body to impart a strength greater than about 1 kPa to the area.

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 some examples, a module of a three-dimensional (3D) printer can include a first linear actuator, a second linear actuator, and a tool to selectively engage a part and selectively disengage from the part, where the tool is connected to the first linear actuator and the second linear actuator.

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 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: 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: 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: 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.

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: A three-dimensional printing system can include polymeric build material and jettable fluid(s). The polymeric build material can have an average particle size from 20 ?m to 150 ?m, a first melt viscosity, and a melting temperature from 75° C. to 350° C. In one example, the jettable fluid can include water, from 0.1 wt % to 10 wt % of electromagnetic radiation absorber, and from 10 wt % to 35 wt % of an organic solvent plasticizer. Contacting a first portion of a layer of the polymeric build material with the jettable fluid can provide an organic solvent plasticizer loading from 2 wt % to 10 wt % based on the polymeric build material content. The first melt viscosity of the polymeric build material at the first portion can be reduced and the melting temperature of the polymeric build material at the first portion can be decreased by 3° C. to 15° C.

Abstract: Example described herein include a three-dimensional printer a threedimensional printing device that includes a fusible material applicator to apply a layer of fusible material, a inhibiting material applicator to apply a patterned layer of inhibiting material to establish exposed regions of the layer of fusible material and blocked regions of the layer of fusible material based on information corresponding to a three-dimensional model, and a photonic energy emitter to apply photonic energy to fuse the exposed regions of the layer of fusible material.

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.