Abstract: The present disclosure is drawn to coalescent inks and material sets for 3D printing. The coalescent ink can include a water-soluble near-infrared dye having a peak absorption wavelength from 800 nm to 1400 nm. The coalescent ink can also contain water.

Abstract: An additive manufacturing system includes a platen having a top surface to support an object being manufactured, a support structure, an actuator coupled to at least one of the platen or the support structure to create relative motion there between along a first axis parallel to the top surface, a plurality of printheads mounted on the support structure, and an energy source. Each printhead includes a dispenser to deliver a plurality of successive layers of feed material over the platen. The printheads are spaced along a second axis perpendicular to the first axis such that during motion along the first axis the plurality of printheads dispense feed material in a plurality of parallel swaths along the first axis. The energy source is configured to fuse at least a portion of the feed material.

Abstract: An additive manufacturing apparatus includes a dispensing system positionable over a platen to deliver a powder, an actuator to move the dispensing system along a scan axis, and an energy source to fuse a portion of the powder. The dispensing system has a hopper to hold the powder and a dispenser. The dispenser includes a channel extending along a longitudinal axis from a proximal end to a distal end. The proximal end of the channel of the dispenser is configured to receive the powder from the powder source. A powder conveyor is positioned within the channel to move the powder from the proximal end along a length of the channel, and a plurality of apertures are arranged along the longitudinal axis of the channel. The dispenser is configured such that flow of powder through each aperture is independently controllable.

Abstract: Provided in one example herein is an aqueous ink composition, including: pigment particles having at least one metal oxide; an aqueous medium; and a cationic double-chain surfactant consisting a quaternary ammonium salt. Methods of making and using the ink composition are also provided.

Abstract: An apparatus for positioning micro-devices on a substrate includes one or more supports to hold a donor substrate and a destination substrate, an adhesive dispenser to deliver adhesive on micro-devices on the donor substrate, a transfer device including a transfer surface to transfer the micro-devices from the donor substrate to the destination substrate, and a controller. The controller is configured to operate the adhesive dispenser to selectively dispense the adhesive onto selected micro-devices on the donor substrate based on a desired spacing of the selected micro-devices on the destination substrate. The controller is configured to operate the transfer device such that the transfer surface engages the adhesive on the donor substrate to cause the selected micro-devices to adhere to the transfer surface and the transfer surface then transfers the selected micro-devices from the donor substrate to the destination substrate.

Abstract: In an example implementation, a method of three-dimensional (3D) printing includes applying a sinterable material, selectively applying a fusing agent on a portion of the sinterable material, applying a first amount of radiation energy to the portion of the sinterable material, and applying a second amount of radiation energy to the portion of the sinterable material different than the first amount of radiation energy.

Abstract: An additive manufacturing system includes a platen having a top surface to support an object being manufactured, a feed material dispenser to deliver a plurality of successive layers of feed material over the platen, an energy source positioned above the platen to fuse at least a portion of an outermost layer of feed material, and a coolant fluid dispenser to deliver a coolant fluid onto the outermost layer of feed material after at least a portion of the outermost layer has been fused.

Abstract: A method of fabricating a polishing pad using an additive manufacturing system includes receiving data indicative of a desired shape of the polishing pad to be fabricated by droplet ejection. The desired shape defines a profile including a polishing surface and one or more grooves on the polishing pad. Data indicative of a modified pattern of dispensing feed material is generated to at least partially compensate for distortions of the profile caused by the additive manufacturing system, and a plurality of layers of the feed material are dispensed by droplet ejection in accordance to the modified pattern.

Abstract: In one example, a non-transitory processor readable medium having instructions thereon that when executed cause an additive manufacturing machine to expose build material to a light source emitting monochromatic light within a band of wavelengths that includes a peak light absorption of a liquid coalescing agent to be dispensed on to the build material.

Abstract: Additive manufacturing of an object includes dispensing a plurality of successive layers of powder over a top surface of a platform, fusing an object region in each of the plurality of successive layers to form the object, and fusing a brace region in a particular layer from the plurality of layers to form a brace structure to inhibit lateral motion of the powder. The brace structure is spaced apart from the particular object region by a gap of unfused powder.

Abstract: In one example, a non-transitory processor readable medium with instructions thereon that when executed cause an additive manufacturing machine to inhibit build material from coalescing in an area of a first layer of build material where a second slice of an object will overhang a first slice of the object formed in the first layer of build material.

Abstract: An additive manufacturing apparatus includes a dispensing system positionable over a platen to deliver a powder, an actuator to move the dispensing system along a scan axis, and an energy source to fuse a portion of the powder. The dispensing system has a hopper to hold the powder and a dispenser. The dispenser includes a channel extending along a longitudinal axis from a proximal end to a distal end. The proximal end of the channel of the dispenser is configured to receive the powder from the powder source. A powder conveyor is positioned within the channel to move the powder from the proximal end along a length of the channel, and a plurality of apertures are arranged along the longitudinal axis of the channel. The dispenser is configured such that flow of powder through each aperture is independently controllable.

Abstract: An additive manufacturing apparatus includes a platform, a first support, a first actuator to create relative motion along a first axis such that the first support scans across the platform, one or more printheads supported on the first support above the platform and configured to dispense successive layers of feed material to form a polishing pad, a second support, a second actuator to create relative motion along a second axis substantially perpendicular to the first axis such that the second support scans across the platform in a direction perpendicular to the first axis, and a plurality of individually addressable energy sources supported on the second support above the platform, and a controller. The energy sources are arranged in an array that extends at least along the first axis and configured to emit radiation toward the platform.

Abstract: In a 3D printing method, a coalescent dispersion for forming a 3D object is selected. The dispersion includes an aqueous vehicle and an infrared or near-infrared binding agent dissolved or dispersed therein. The binding agent is a phthalocyanine having a polar group attached to each side chain or a naphthalocyanine having a polar group attached to each side chain. A sinterable material is deposited and heated to a temperature ranging from about 50 C to about 350 C. The dispersion is selectively applied on at least a portion of the sinterable material. The sinterable material and the dispersion applied thereon are exposed to infrared or near-infrared radiation. The binding agent absorbs the radiation and converts it to thermal energy. At least the portion of the sinterable material in contact with the binding agent is at least cured to form a first layer of the 3D object.

Abstract: A polymeric powder composition for three-dimensional printing includes first, second, and third polymeric particles. The first particles, having a first average size, are present in an amount ranging from about 70 wt % to about 95 wt %. The second particles, having a second average size smaller than the first average size, are present in an amount ranging from about 0.5 wt % to about 21 wt %. The third particles, having a third average size smaller than the second average size, are present in an amount ranging from greater than 0 wt % up to about 21 wt %. Each of the first, second, and third average sizes independently ranges from 5 ?m to about 100 ?m. A sum of the fractional weight ratios of all of the polymeric particles in the polymeric powder composition equals 1.

Abstract: In one example, a non-transitory processor readable medium with instructions thereon that when executed cause an additive manufacturing machine to inhibit build material from coalescing in an area of a first layer of build material where a second slice of an object will overhang a first slice of the object formed in the first layer of build material.

Abstract: A method of fabricating a polishing pad using an additive manufacturing system includes receiving data indicative of a desired shape of the polishing pad to be fabricated by droplet ejection. The desired shape defines a profile including a polishing surface and one or more grooves on the polishing pad. Data indicative of a modified pattern of dispensing feed material is generated to at least partially compensate for distortions of the profile caused by the additive manufacturing system, and a plurality of layers of the feed material are dispensed by droplet ejection in accordance to the modified pattern.

Abstract: An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material on the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife supply unit. The air knife supply unit includes a tube having a plurality of holes spaced along a length of the tube, a multi-fluted helical screw positioned in the tube, a gas inlet configured to supply a gas into an end of the tube with the screw configured to guide the gas from the gas inlet through the tube and out the holes, and a spiral plenum surrounding the tube with the spiral plenum including an inner end to receive gas from the holes and an outer end to deliver the gas over the platform.

Abstract: A module for an additive manufacturing system includes a frame, a dispenser configured to deliver a layer of particles over a platen, an energy source to generate a beam to fuse the particles, and a metrology system having a first sensor to measure a property of the surface of layer before being fused and a second sensor to measure a property of the layer after being fused. The dispenser, first sensor, energy source and second sensor are positioned on the frame in order along a first axis, and the dispenser, first sensor, energy source and second sensor are fixed to the frame such that the frame, dispenser, first sensor, energy source and second sensor can be mounted and dismounted as a single unit from a movable support.

Abstract: In one implementation, a method of forming a porous polishing pad is provided. The method comprises depositing a plurality of composite layers with a 3D printer to reach a target thickness. Depositing the plurality of composite layers comprises dispensing one or more droplets of a curable resin precursor composition onto a support. Depositing the plurality of composite layers further comprises dispensing one or more droplets of a porosity-forming composition onto the support, wherein at least one component of the porosity-forming composition is removable to form the pores in the porous polishing pad.