Abstract: Methods of three-dimensional printing can include iteratively applying a polymer build material as individual layers to a powder bed, where the polymer build material includes from about 80 wt % to 100 wt % polymer build particles, and based on a three-dimensional object model, selectively applying a binder agent including an aqueous liquid vehicle and polymer binder particles onto the individual layers of the polymer build material. The polymer binder particles have or are capable of having a melting temperature lower than a melting temperature of the polymer build particles. The methods can include exposing the powder bed to heat at a temperature less than a melting point of the polymer build particles but greater than a melting temperature of the polymer binder particles. The heat causes the polymer binder particles to melt to adhere the polymer build particles together to form a three-dimensional object.

Abstract: A method of three-dimensional printing can include iteratively applying a polymer build material as individual layers to a powder bed, where the polymer build material includes from about 80 wt % to 100 wt % polymeric particles, and based on a three-dimensional object model, selectively applying a coalescing agent onto individual layers of the polymer build material. The coalescing agent can include an aqueous liquid vehicle and a coalescing solvent that depresses a melting point of the polymeric particles. The method can include exposing the powder bed to heat to selectively coalesce portions of individual layers of the polymer build material in contact with the coalescing solvent. The heat may not be sufficient to coalesce the polymer build material that is not in contact with the coalescing solvent and may be sufficient to fuse the polymeric particles in contact with the coalescing solvent together to form a three-dimensional object.

Abstract: A hardening agent for three-dimensional printing includes a boron-containing hardener and a jettable liquid vehicle, and is devoid of a pigment and a dye. The boron-containing hardener is selected from the group consisting of a water dispersible boron-containing hardener present in an amount ranging from about 6 wt % to about 15 wt %, and a water soluble boron-containing hardener present in an amount ranging from greater than 1 wt % to about 20 wt %.

Abstract: In an example three-dimensional printing method, individual layers of a metal-based build material are patterned, based on a 3D object model, with a binding agent to form an intermediate structure. A case-hardened portion of a 3D object is also patterned (based on the object model) by selectively depositing a hardening agent to deliver a predetermined concentration of a hardening element to at least one of the individual layers, wherein the individual layers are maintained below a vaporization temperature of the hardening agent during the selectively depositing. The intermediate structure is heated at a first rate to a temperature that aids in diffusion of the hardening element, and is held at the temperature for a predetermined time. The intermediate structure is cooled at a second rate. The intermediate structure, with the patterned case-hardened portion, is then sintered at a sintering temperature of the metal-based build material.

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: A device for forming spherical particles may include a receiving chamber having a heating portion and a cooling portion. Wire segments may travel in a free fall through the receiving chamber. While falling through the heating portion, wire segments may be heated to form spherical particles in response to exposure to microwave electromagnetic radiation. While falling through the cooling portion, formed spherical particles cool.

Abstract: In an example implementation, a method of 3D printing includes receiving a 2D data slice derived from a 3D object model, where the 2D data slice defines an object area of a layer of build material that is to receive a liquid functional agent and be fused as a layer of a part. The method includes determining that the 2D data slice distinguishes first and second tolerance zones within the object area. The method includes controlling a printhead to print a liquid functional agent onto the layer of build material according to a first droplet ejection spacing when printing in the first tolerance zone, and controlling the printhead to print a liquid functional agent onto the layer of build material according to a second droplet ejection spacing when printing in the second tolerance zone.

Abstract: A hardening agent for three-dimensional printing includes a boron-containing hardener and a jettable liquid vehicle, and is devoid of a pigment and a dye. The boron-containing hardener is selected from the group consisting of a water dispersible boron-containing hardener present in an amount ranging from about 6 wt % to about 15 wt %, and a water soluble boron-containing hardener present in an amount ranging from greater than 1 wt % to about 20 wt %.

Abstract: In one example, testing cells extend along a length of a slot. Each testing cell includes a microfluidic channel extending from the slot, a pump to move fluid from the slot into the channel, a discharge nozzle through which fluid exits the channel, a fluid discharger to discharge fluid from the channel through the nozzle and a photosensor. A light guide is provided to receive light from an external light source and is to serially transmit the light to the microfluidic channel of each of the plurality of testing cells.

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: In one example, testing cells extend along a length of a slot. Each testing cell includes a microfluidic channel extending from the slot, a pump to move fluid from the slot into the channel, a discharge nozzle through which fluid exits the channel, a fluid discharger to discharge fluid from the channel through the nozzle and a photosensor. A light guide is provided to receive light from an external light source and is to serially transmit the light to the microfluidic channel of each of the plurality of testing cells.

Abstract: In one embodiment, a fluid ejector structure includes an array of fluid ejector elements; an array of fluid ejection orifices, each orifice in the array positioned adjacent to a corresponding one of the fluid ejector elements; and a three dimensional array of interconnected conductors within the orifice and ejector element arrays. In another embodiment an orifice sub-structure for a fluid ejector structure includes: a substrate; an array of orifices in the substrate arranged in rows in an x direction and in columns in a y direction; and a first thin film structure that includes first conductive elements within the orifice array extending in the x direction and in the y direction.

Abstract: A fluid ejection assembly includes a platform having a fluid inlet, a fluid outlet, a plurality of fluid feed slots, and a fluid manifold defined therein, and a plurality of fluid ejection devices each mounted on the platform and including an array of drop ejecting elements and a fluid refill slot communicating with the array of drop ejecting elements. The fluid refill slot of each of the fluid ejection devices communicates with at least one of the fluid feed slots of the platform, and the fluid manifold of the platform fluidically couples each of the fluid feed slots with the fluid inlet and the fluid outlet of the platform.

Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.

Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.

Abstract: A method of forming an electrical connection for a fluid ejection device including a fluid channel communicating with a first side and a second side of the fluid ejection device and an array of drop ejecting elements formed on the first side of the fluid ejection device includes forming a trench in the second side of the fluid ejection device, depositing a conductive material in the trench, forming a first opening in the fluid ejection device between the first side of the fluid ejection device and the conductive material in the trench, depositing a conductive material in the first opening, and forming a conductive path between the conductive material in the first opening and a wiring line of one of the drop ejecting elements.

Abstract: A memory apparatus has a plurality of first electrodes and at least one second electrode separated by an electrolyte solution. Information may be recorded by causing an electrical current to flow between a selected of the first electrodes and the second electrode to deposit an electrochemically active material on one of the selected first or the second electrodes. A method for recording and reading information has steps of writing the information by causing a current to flow between a first and a second electrode through an electrolyte solution to cause an electrochemically active material to electrodeposit, and reading the information by sensing the deposited material with a sensor.

Abstract: Described herein is a monolithic printhead formed using integrated circuit techniques. Thin film layers, including ink ejection elements, are formed on a top surface of a silicon substrate. The various layers are etched to provide conductive leads to the ink ejection elements. At least one ink feed hole is formed through the thin film layers for each ink ejection chamber. A trench is etched in the bottom surface of the substrate so that ink can flow into the trench and into each ink ejection chamber through the ink feed holes formed in the thin film layers. An orifice layer is formed on the top surface of the thin film layers to define the nozzles and ink ejection chambers. A phosphosilicate glass (PSG) layer, providing an insulation layer beneath the resistive layers, is etched back from the ink feed holes and is protected by a passivation layer to prevent the ink from interacting with the PSG layer. Other layers may also be protected from the ink by being etched back.

Abstract: Pillars are formed in a fully integrated thermal inkjet printhead to prevent particles from entering into a nozzle chamber along an ink refill channel. The pillars are formed after a step of applying a thin film structure to a substrate. At one step, pits are etched through the thin film structure. At another step, material for an orifice layer is deposited into the pits. At another step, a firing chamber is etched into the orifice layer. At another step, a trench is etched into the backside of the wafer in the vicinity of the filled pits. The material filling each pit is not removed and remains in place to define the respective pillars. Two or more pillars are formed within the trench for each inkjet nozzle chamber. Alternatively pillars are formed by depositing material into the underside trench and performing photoimaging processes.

Abstract: A porous foam based ink containment system is provided with grooves defined in the exterior portion thereof, for storing ink, while preventing ink leakage from the ink-jet pen. The grooves provide passageways to allow air diffused throughout the ink and trapped air bubbles within the foam to expand and move to the atmosphere. An atmospheric vent is in fluid communication with at least one of the grooves.