Abstract: In one example, a decaking system for 3D printing includes a platform to support multiple green parts in unbound powder surrounding the green parts, a decaking tool to remove unbound powder from around the green parts, a camera to photograph green parts on the platform as unbound powder is removed from around the green parts, and a controller operatively connected to the camera. The controller is programmed to detect a pattern of light intensity in the photographs and, in response to a determination a detected pattern matches a reference pattern, modulate or stop the decaking tool.

Abstract: An additive manufacturing process which comprises carrying out an additive manufacturing build process to create a build cake. The build cake comprises a build object and non-solidified build material and the build object is built in a build location within the build cake. The build cake is supported on a tray which comprises a mesh having openings therethrough. The tray also includes an object region and a restraining feature to restrain a build object within the object region. The process comprises performing a decake operation in which non-solidified build material from the build cake passes through the openings of the mesh and the object moves into contact with the tray in the object region so that the object is restrained within the object region of the tray by the restraining feature.

Abstract: In one example in accordance with the present disclosure, a build material volume transportation device is described. The build material volume transportation device includes a shuttle to transport a build material volume. The shuttle includes an opening therethrough to receive the build material volume. The build material volume transportation device also includes a build tray to raise the build volume into the opening in the shuttle. The build material volume transportation device further includes a latch assembly to releasably secure the build tray to the shuttle. A tip of the latch assembly extends to interface with the aperture to secure the build tray to the shuttle. The tip rotates independently of the piston.

Abstract: A method is described in which a digital model of a part to be formed within a build bed is received. The model is rotated within a build volume of the build bed such that the projected area of the part in a plane normal to a flow axis is reduced. The flow axis is an axis along which a flow of gas moves through the build bed during a post-print operation, or the flow axis is defined by a type of post-print operation to be performed on the build bed.

Abstract: In one example, a system for loading a build material powder supply container for 3D printing includes a dispenser to dispense a build material powder into a supply container, a device to measure a density of the build material powder in the supply container, a compactor to compact the build material powder in the supply container, and a controller operatively connected to the measuring device and the compactor. The controller is programmed to control the compactor to compact the build material powder in the supply container until a measured density reaches a threshold density.

Abstract: In one example, a system for loading a build material powder supply receptacle for a 3D printer includes a reconditioner having a container and a heater to burn unwanted residue from used build material powder in the container, to form reconditioned build material powder, a conveyor operatively connected to the reconditioner to convey used build material powder to the container, and a dispenser operatively connected to the reconditioner to dispense reconditioned build material powder from the container into the supply receptacle.

Abstract: Disclosed is a sealing member for a build unit of a 3D printing system, the build unit comprising a surface which is exposed to residual build material in use. The sealing member is adapted to engage with the build unit and form therewith a sealed fluid flow path comprising an inner surface including said surface, a fluid inlet and a fluid outlet.

Abstract: According to one aspect, there is provided an apparatus for loading powder into a powder supply chamber. The apparatus comprises a powder supply module to supply powder to a supply chamber, a set of powder compaction elements and a controller. The controller is to control the powder supply module to supply powder to the supply chamber, control the compaction member to distribute and compact the supplied powder, and control the height of the supply platform and the flow of powder to the supply chamber to load the supply chamber with powder.

Abstract: An example of an apparatus to decake a 3D printed part is disclosed. The apparatus comprises a housing including at least a conduit connectable to a gas source and at least a channel connectable to a vacuum source. The conduit, when in use, is to direct a gas flow to remove un-solidified build material particles from a surface of a 3D printed part. The channel, when in use, is to direct an airflow that generally surrounds the gas flow to extract the removed un-solidified build material particles.

Abstract: According to one aspect, there is provided a method of cleaning a 3D object on a platform. The method comprises generating with a cleaning module a cleaning airflow to remove powder particles from a 3D object and an extraction airflow to extract any removed powder particles, determining a quantity of powder particles in the extraction airflow, and moving the cleaning module relative to the platform based on the determined quantity of powder particles.

Abstract: A build platform of an additive manufacturing apparatus is disclosed. The build platform includes a surface formed of a material having a first emissivity; and a plurality of reference markers disposed on the surface. The reference markers have a second emissivity that is different from the first emissivity. A thermal imaging unit calibration method and additive manufacturing apparatus are also disclosed.

Abstract: According to one example, there is provided apparatus for restraining objects during a powder and object separation process. The apparatus comprises a base plate comprising a set of spatially arranged apertures, a set of rods, each rod slidable within a corresponding aperture of the base plate. The base plate is to connect with a chamber to contain a volume of powder and objects to be separated and the apparatus is configured such that, when the apparatus is connected to a chamber containing a volume of powder and 3D objects the set of rods are positionable in, or are slideable into, a position extending vertically away from the chamber, and as powder is removed from under each rod, the rods are to slide through the apertures.

Abstract: A three-dimensional printer is described, wherein the three-dimensional printer comprises a build unit and a material removal unit. The build unit is configured to generate a three dimensional object. The material removal unit comprises a housing, a plurality of gas inlets and outlets, a plurality of valves and a control unit. The housing is sealed to the build unit and is configured to house a cake comprising the generated three dimensional object. The valves are configured to open and close the inlets and outlets, and the control unit is configured to control the valves, to allow gas to flow from different inlets to different outlets in different flow paths, in order remove powder from the object.

Abstract: A sensor calibration method is disclosed. The method includes applying thermal energy to a fabrication chamber of an additive manufacturing apparatus to raise a temperature of a surface within the fabrication chamber to a first surface temperature; measuring, using a first sensor to be calibrated, the first surface temperature; measuring, using a second sensor, the first surface temperature; applying thermal energy to the fabrication chamber to raise a temperature of the surface to a second surface temperature; measuring, using the first sensor, the second surface temperature; measuring, using the second sensor, the second surface temperature; determining, using a processor, based on the first and second surface temperatures measured using the first sensor and on the first and second surface temperatures measured using the second sensor, an offset calibration to be applied to measurements obtained using the first sensor; and applying the offset calibration to measurements obtained using the first sensor.

Abstract: An apparatus comprises a controller to cause an additive manufacturing system to perform a method, the method comprising: controlling the additive manufacturing system to provide a plurality of articles in a multi-layer build arrangement in a build chamber, the multi-layer build arrangement comprising a plurality of article layers, each article layer comprising an article; ejecting a portion of the multi-layer build arrangement from the build chamber; and determining when a divider can be used to divide a first volume of build material of the multi-layer build arrangement from a remaining volume of build material of the multi-layer build arrangement, wherein the first volume comprises an article layer.