Abstract: Some examples include an additive manufacturing machine including a build chamber including a build area and a dose plate, a build material dispenser to dispense a mass of a build material onto the dose plate, a light source to transmit a light energy through the build material on the dose plate, a light sensor to sense a light energy transmitted through the build material on the dose plate, and a controller to control the build material dispenser to adjust a next build material dose mass based on a sensed light energy transmission.

Abstract: An example of a build material for three-dimensional (3D) printing includes a preconditioned polymer or polymer composite powder. A percent crystallinity of the preconditioned polymer or polymer composite powder is reduced by a volume percentage ranging from about 0.5% to about 3% compared to a percent crystallinity of a corresponding untreated polymer or polymer composite powder.

Abstract: Some examples include a method of operating an additive manufacturing machine including spreading a build material in a first direction across a build surface to form a layer, the layer having a thickness, decreasing a distance between a spread mechanism and the build surface, and translating the spread mechanism in a second direction opposite the first direction over the build surface to reduce the thickness of the layer.

Abstract: Some examples include a method of operating an additive manufacturing machine including forming a layer of a build material, selectively applying a fusing agent onto the formed layer of build material, applying fusing energy to the build material and fusing agent with a thermal energy source to form an object layer of a three dimensional object and a sacrificial layer of a sacrificial object at the selectively applied fusing agent, sensing a thermal temperature of the sacrificial layer, comparing the sensed thermal temperature of the sacrificial layer to a target temperature, and adjusting a power level of the thermal energy source based on the compared temperatures.

Abstract: Systems may reduce fugitive particles of powdered build materials in additive manufacturing by including a shroud positioned over a powder spreading roller, wherein the shroud forms a passageway to transport the fugitive particles. The bottom of the shroud forms a horizontally elongate opening to fit over an upper circumferential portion of the roller, leaving a lower circumferential portion extending out therefrom. The shroud may also be connected to a fan, blower, or other suction source to transport fugitive particles along a passageway, through a filter, and into a bin for collection or potential recycling. The system may include a brush or scraper positioned in the shroud and which contacts the spreading roller to help physically remove any fugitive particles that might be stuck to the roller.

Abstract: An apparatus calibrates the optical sensor to calibrate the distance measured by the sensor with the expected distance using a calibration surface at the expected distance.

Abstract: The technology described herein includes a spreader that creates scattered incidental particles in a build chamber when spreading build material is applied in the build platform. One or more vacuum sources create negative pressure zones in one or more receptacles to collect the incidental particles in the build chamber during printing process and thus minimize the scattering of the incidental particles.

Abstract: According to an example, a scanner apparatus may include a housing, a scan panel positioned on the housing and a lid rotatably mounted to the housing. The lid may be moved between a closed position and an open position, in which in the closed position, the lid covers the scan panel and in the open position, the lid is extended away from the scan panel. The scanner apparatus may also include an optical sensor to detect media placed on the scan panel and a media engine to determine whether the optical sensor has detected a media on the scan panel while the lid is in the open position.

Abstract: In one example, a lighting assembly includes a housing to hold an elongated lamp and an elongated device attached to or integral with the housing and configured to, when an lamp is held in the housing, convert light from the lamp having a first irradiance that is non-uniform along a length into light having a second irradiance that is uniform along the length.

Abstract: Example implementations relate to an edge sensing apparatus. For example, an edge sensing apparatus consistent to the present disclosure may include a reflector in a beam path of a retroreflective sensor. The edge sensing apparatus consistent with the present disclosure may include a cover glass located between the retroreflective sensor and the reflector. The edge sensing apparatus consistent with the present disclosure may include a media feeder to feed a media along a media path between the cover glass and the retroreflective sensor.

Abstract: A reflector includes a first reflector section and a second reflector section. The first reflector section extends along a portion of a first ellipse. The second reflector section extends along a portion of a second ellipse, the second ellipse intersecting the first ellipse. The first reflector section and the second reflector section are joined at an intersecting point of the first ellipse and the second ellipse.

Abstract: A printing apparatus includes a media bin and a sensor, directed toward the media bin, having a first emitter and a receiver. The printing apparatus further includes a second emitter to emit photons toward the optical sensor, and a controller. The controller determines presence of a print media on the media bin based on a count of photons received from a source other than the first emitter, including the second emitter.

Abstract: According to examples, a printing apparatus may include an output bin that is laterally translatable between a retracted position and an extended position. The printing apparatus may also include a sensor to detect a height of a stack of media on the output bin while the output bin is in the retracted position and a controller. The controller may determine whether the detected height of the stack of media on the output bin exceeds a certain level and in response to a determination that the detected height of the stack of media exceeds the certain level, laterally translate the output bin from the retracted position to the extended position.

Abstract: According to an example, a scanner apparatus may include a housing, a scan panel positioned on the housing and a lid rotatably mounted to the housing. The lid may be moved between a closed position and an open position, in which in the closed position, the lid covers the scan panel and in the open position, the lid is extended away from the scan panel. The scanner apparatus may also include an optical sensor to detect media placed on the scan panel and a media engine to determine whether the optical sensor has detected a media on the scan panel while the lid is in the open position.

Abstract: In one example a bend sensor is disclosed. The bend sensor extends into a media tray. The bend sensor has a tip where a deflection amount of the tip indicates a media parameter.

Abstract: Example implementations relate to an edge sensing apparatus. For example, an edge sensing apparatus consistent to the present disclosure may include a reflector in a beam path of a retroreflective sensor. The edge sensing apparatus consistent with the present disclosure may include a cover glass located between the retroreflective sensor and the reflector. The edge sensing apparatus consistent with the present disclosure may include a media feeder to feed a media along a media path between the cover glass and the retroreflective sensor.

Abstract: In an example implementation, a method of printing a three-dimensional (3D) object includes scanning a print bar in a first direction over a build platform of a 3D printer to deposit a liquid agent onto a layer of build powder. The print bar is then indexed in a second direction substantially orthogonal to the first direction before scanning the print bar back over the build platform in a third direction opposite the first direction to deposit additional liquid agent onto the layer of build powder.

Abstract: A reflector includes a first reflector section and a second reflector section. The first reflector section extends along a portion of a first ellipse. The second reflector section extends along a portion of a second ellipse, the second ellipse intersecting the first ellipse. The first reflector section and the second reflector section are joined at an intersecting point of the first ellipse and the second ellipse.

Abstract: In one example, a reflector assembly includes a single reflector having at least two elliptical-shaped reflector cavities each with a respective focus point. The shape of the single reflector includes two partial elliptical-shaped reflector cavities having mirror-asymmetric profiles on each end of the single reflector each having a first side extending to a distal end and the first side longer than an opposite second side. The remaining elliptical-shaped reflector cavities have a first side and a second side the same length as the opposite second sides of the two partial elliptical-shaped reflector cavities.

Abstract: In one example, a fusing system for an additive manufacturing machine includes a first carriage carrying a layering device and a fusing lamp, and a second carriage carrying a fusing agent dispenser. The first carriage and the second carriage are movable back and forth over the work area along the same line of motion so that the first carriage follows the second carriage in one direction and the second carriage follows the first carriage in the other direction.