Abstract: The present disclosure is drawn to material sets for 3-dimensional printing, 3-dimensional printing systems, and 3-dimensional printed parts. A material set can include a thermoplastic polymer powder having an average particle size from 20 ?m to 100 ?m, an x-ray contrast ink including a jettable x-ray contrast agent, and a fusing ink. The fusing ink can include a fusing agent capable of absorbing electromagnetic radiation to produce heat.

Abstract: In a three-dimensional printing method example, a pre-treatment coating is formed on a part precursor by applying and drying, alternatingly: a polycation solution including a chloride ion and a polyanion solution including a sodium ion to form at least two layers. An ink is selectively deposited on the pre-treatment coating.

Abstract: A first object for assembly with a second object, the first object comprising: a body having a first mating portion; and a first electronic element fabricated on the body; wherein the first electronic element is provided to establish an electrical coupling with a second electronic element fabricated on one of: the body and the second object, wherein a second mating portion is provided on the second object, and wherein the electrical coupling is configured to provide a measurable output for positioning the first mating portion at a desired position relative to the second mating portion according to an analysis of the measurable output against a predetermined reference output.

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 polymeric or polymeric composite build material, and a precipitating agent. Based on a 3D object model, a fusing agent is selectively applied on at least a portion of the build material composition. The fusing agent includes a radiation absorber, which the precipitating agent precipitates. The build material composition is exposed to radiation to fuse the at least the portion to form a layer of a 3D part.

Abstract: An example of a build material composition for three-dimensional (3D) printing includes a polymeric or polymeric composite build material and a wetting modifying agent. The wetting modifying agent is: (i) incorporated into the polymeric component of the polymeric or polymeric composite build material and changes the wetting behavior of the polymeric component; or (ii) selected from the group consisting of: a fluorotelomer; a C8-C20 alcohol; a methyltrialkyl ammonium chloride; docusate sodium salt; a polymer having a chemical structure of the polymeric component of the polymeric or polymeric composite build material modified to include a hydrophobic group or a hydrophilic group; and a combination thereof.

Abstract: The present disclosure is drawn to material sets for 3-dimensional printing. The material set can include a thermoplastic polymer powder having an average particle size from 20 ?m to 100 ?m, a conductive fusing ink comprising a transition metal, and second fusing ink. The second fusing ink can include a fusing agent capable of absorbing electromagnetic radiation to produce heat. The second fusing ink can provide a lower conductivity than the conductive fusing ink when printed on the thermoplastic polymer powder.

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 some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.

Abstract: A temperature sensor can include a resistor, a first electrical contact at a first end of the resistor, a second electrical contact at a second end of the resistor, and a resistance measuring device. The resistor can be formed of a matrix of sintered elemental transition metal particles interlocked with a matrix of fused thermoplastic polymer particles. The resistance measuring device can be connected to the first electrical contact and the second electrical contact to measure a resistance of the resistor.

Abstract: The present disclosure is drawn to material sets for 3-dimensional printing. The material set can include a thermoplastic polymer powder having an average particle size from 20 ?m to 200 ?m, a conductive fusing agent composition including a transition metal, and nonconductive fusing agent composition. The nonconductive fusing agent composition can include transition metal oxide bronze particles.

Abstract: A 3-dimensional printed load cell part can include a part body formed of fused thermoplastic polymer particles, and a plurality of strain sensors separately formed of a matrix of conductive particles interlocked with a matrix of fused thermoplastic polymer particles. The plurality of strain sensors can have a first electrical contact at a first end and a second electrical contact at a second end. The particles of the plurality of strain sensors can be continuously fused to the particles of the part body.

Abstract: A strain sensor can include a resistor, a first electrical contact at a first end of the resistor, and a second electrical contact at a second end of the resistor. The resistor can be formed of a matrix of sintered elemental transition metal particles interlocked with a matrix of fused thermoplastic polymer particles.

Abstract: The present disclosure is drawn to a pigment-based inkjet ink and methods. The inkjet ink includes water; from 2 wt % to 9 wt % pigment solids; from 0.05 wt % to 2 wt % of an acetylenic diol non-ionic surfactant; from 0.05 wt % to 2 wt % of a second surfactant. The second surfactant can be a polysorbate having at least 50% lipophilic oleic acid groups and having an HLB value of less than 15, or a C12-C18 polyoxyethylene glycol ether having an ethylene oxide number less than 20, or a perfluoropolyether including a polyethylene glycol primary alcohol or diol. The inkjet ink also includes from 5 wt % to 50 wt % of an organic solvent system comprising triethylene glycol and a cyclic amide.

Abstract: The present disclosure is drawn to a dispersed magenta pigment blend, including a first pigment including Pigment Violet 19 and Pigment Red 122, or Pigment Red 282; and a second pigment including Pigment Red 150. The weight ratio of the first pigment to the second pigment can be from 50:50 to 80:20 by pigment solids content.

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 material sets for 3-dimensional printing, 3-dimensional printing systems, and 3-dimensional printed parts. A material set can include a thermoplastic polymer powder having an average particle size from 20 ?m to 100 ?m, an x-ray contrast ink including a jettable x-ray contrast agent, and a fusing ink. The fusing ink can include a fusing agent capable of absorbing electromagnetic radiation to produce heat.

Abstract: In some examples, a controller receives impedance sensor values from an impedance sensor in a printhead, determines whether the impedance sensor values correlate to a production of an effective drive bubble for the printhead, and issues a command to modify a firing parameter for a fluid ejector of the printhead based on the impedance sensor values.

Abstract: According to an example, a three-dimensional (3D) printed heater may include a part body formed of fused thermoplastic polymer particles and an electrically resistive element formed of a matrix of conductive particles interspersed between a matrix of thermoplastic polymer particles. The conductive particles and the thermoplastic polymer particles may be provided at respective densities to cause the electrically resistive element to have a predetermined resistance level. The 3D printed heater may also include electrical contacts connected to the electrically resistive element, in which a current is to be applied through the electrically resistive element via the electrical contacts to cause the electrically resistive element to generate a predefined level of heat.

Abstract: A 3-dimensional printed part can include a part body including a first matrix of fusing agent and thermoplastic polymer powder, a security feature including a second matrix of fusing agent, thermoplastic polymer powder, and photoluminescent agent, and a masking feature including a third matrix of fusing agent and thermoplastic polymer powder. The security feature can be positioned beneath and visible through the masking feature upon photoluminescent emission of the security feature.

Abstract: A 3-dimensional printed load cell part can include a part body formed of fused thermoplastic polymer particles, and a plurality of strain sensors separately formed of a matrix of conductive particles interlocked with a matrix of fused thermoplastic polymer particles. The plurality of strain sensors can have a first electrical contact at a first end and a second electrical contact at a second end. The particles of the plurality of strain sensors can be continuously fused to the particles of the part body.