Abstract: An example additive manufacturing system comprises a first fan associated with a print chamber to flow gas from the print chamber into an exhaust conduit. A sensor is arranged to detect one or more conditions of the gas flowed into the exhaust conduit from the print chamber by the first fan and to output a signal indicative thereof. A second fan is spaced apart in a downstream direction along the exhaust conduit from the first fan and a control unit is arranged to receive the signal from the sensor and to control the second fan in dependence thereon to maintain one or more conditions of the gas extracted from the print chamber.

Abstract: In one example, an additive manufacturing system. An unsealed air supply enclosure for clean air is maintained at a first pressure above an ambient air pressure to inhibit unfiltered ambient air from leaking into the enclosure. An unsealed processing chamber is maintained at a second pressure below the ambient air pressure to inhibit processing chamber air from leaking out of the processing chamber. An air pathway is disposed between the air supply enclosure and the processing chamber to provide clean air from the air supply enclosure to the processing chamber.

Abstract: A method of changing the gas content of a device (100) which comprises a first chamber (110). The method comprises: arranging the device in a first configuration, wherein the first chamber has a first internal volume; providing a flow of a first gas to the first chamber so that the gas content of the first chamber is at least partially changed; transitioning the device from the first configuration to a second configuration, wherein the first chamber has a second internal volume which is grater than the first internal volume.

Abstract: In an example, a method includes acquiring a thermal image of a reflector within an additive manufacturing apparatus through a screen. An energy profile of the thermal image of the reflector may be determined and, based on the energy profile, an operational characteristic of the screen may be determined.

Abstract: In an example, an air filtration apparatus includes a cyclonic particle separation chamber having a first inlet to draw air from a first region, second inlet to draw air from a second region, and an exhaust port. The air filtration apparatus may further include a pressure sensor to sense a pressure of the first region, and a cyclonic air flow controller. The cyclonic air flow controller may control an air inflow received via the second inlet in response to an output from the pressure sensor to maintain a total air flow rate via the exhaust port.

Abstract: Certain examples described herein relate to printer (110, 210) cooling systems of three-dimensional (3D) printers. In an example of a printer (110, 210) cooling system of a three-dimensional (3D) printer (110, 210), a shared air flow volume (120, 220) is for cooling a plurality of internal printer components (130, 140, 230, 240), and a single air inlet (150, 245) delivers ambient air (160) from outside the three-dimensional (3D) printer (110, 210) to the shared air flow volume (120, 220) In certain cases, the shared air flow volume (120, 220) comprises a first air flow conduit (135, 270) for cooling a first internal printer component (130, 230) and a second air flow conduit (145, 275) for cooling a second internal printer component (140, 240). In certain examples, the first and the second air flow conduits (135, 270) are arranged at least partially in parallel.

Abstract: In one example, an additive manufacturing system. An unsealed air supply enclosure for clean air is maintained at a first pressure above an ambient air pressure to inhibit unfiltered ambient air from leaking into the enclosure. An unsealed processing chamber is maintained at a second pressure below the ambient air pressure to inhibit processing chamber air from leaking out of the processing chamber. An air pathway is disposed between the air supply enclosure and the processing chamber to provide clean air from the air supply enclosure to the processing chamber.

Abstract: An example additive manufacturing system comprises a first fan associated with a print chamber to flow gas from the print chamber into an exhaust conduit. A sensor is arranged to detect one or more conditions of the gas flowed into the exhaust conduit from the print chamber by the first fan and to output a signal indicative thereof. A second fan is spaced apart in a downstream direction along the exhaust conduit from the first fan and a control unit is arranged to receive the signal from the sensor and to control the second fan in dependence thereon to maintain one or more conditions of the gas extracted from the print chamber.

Abstract: A method of changing the gas content of a device (100) which comprises a first chamber (110). The method comprises: arranging the device in a first configuration, wherein the first chamber has a first internal volume; providing a flow of a first gas to the first chamber so that the gas content of the first chamber is at least partially changed; transitioning the device from the first configuration to a second configuration, wherein the first chamber has a second internal volume which is grater than the first internal volume.

Abstract: In an example, an air filtration apparatus includes a cyclonic particle separation chamber having a first inlet to draw air from a first region, second inlet to draw air from a second region, and an exhaust port. The air filtration apparatus may further include a pressure sensor to sense a pressure of the first region, and a cyclonic air flow controller. The cyclonic air flow controller may control an air inflow received via the second inlet in response to an output from the pressure sensor to maintain a total air flow rate via the exhaust port.

Abstract: In an example, a filtration apparatus includes a cyclonic particle separation chamber having an inner surface and a liquid source. The liquid source may be to supply liquid to provide a flow of liquid on the inner surface.

Abstract: An airborne particle detector comprises a light source to emit a light beam through a target space adjacent to a heat source of a 3D printer, a detector to detect an amount of light of the light beam having passed through the target space, and a detection engine in communication with the light source and the detector to detect airborne particles in the target space using an amount of light detected by the detector.

Abstract: In some examples, a carriage for a printing system includes a printhead, a conduit to carry a cooling airflow to the printhead, a return chamber to receive a heated exhaust airflow produced from heating of the cooling airflow by the printhead, and a seal between the printhead and the return chamber to prevent the heated airflow from flowing to a location below the printhead.

Abstract: In an example, a method includes acquiring a thermal image of a reflector within an additive manufacturing apparatus through a screen. An energy profile of the thermal image of the reflector may be determined and, based on the energy profile, an operational characteristic of the screen may be determined.

Abstract: In some examples, a lamp assembly for a printing system includes a heating lamp to generate heat in an active region of the printing system, and a housing comprising an inner chamber containing the heating lamp, an airflow inlet to receive a cooling airflow for provision into the inner chamber of the housing to cool the heating lamp, and a plurality of exhaust holes through which heated exhaust air is to exit from the inner chamber of the housing, the plurality of exhaust holes formed in a wall of the housing. The lamp assembly further includes an attachment element to attach the lamp assembly to a carriage of the printing system.

Abstract: In some examples, a printing system includes a printhead that is relatively moveable with respect to a print platform, and an airflow generator assembly to generate a first cooling airflow towards the printhead responsive to the printhead being at in a first inactive region on a first side of the print platform, and generate a second cooling airflow towards the printhead responsive to the printhead being in a second inactive region on a second, different side of the print platform.

Abstract: An airborne particle detector comprises a light source to emit a light beam through a target space adjacent to a heat source of a 3D printer, a detector to detect an amount of light of the light beam having passed through the target space, and a detection engine in communication with the light source and the detector to detect airborne particles in the target space using an amount of light detected by the detector.

Abstract: In one example, a print head drop detector (202) is described. The print head drop detector (202) comprises a sampling volume and a fan (208) to cause an airflow though the sampling volume (206). Detection apparatus to detect the presence of non-gaseous material within the sampling volume is also provided.