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.

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.

According to one example, there is provided a method of cleaning a filter in a filter housing. The filter has a dirty side at which a dirty airflow is received, and a clean side through which a cleaned airflow flows. The method comprises generating a cleaning airflow at the dirty side of the filter, the cleaning airflow having a predetermined volume and pressure, and generating an extraction airflow to extract from the filter housing the same volume and pressure of air from the filter housing as that generated in the filter housing by the cleaning airflow.

According to one example, there is provided a method of cleaning a filter in a filter housing. The filter has a dirty side at which a dirty airflow is received, and a clean side through which a cleaned airflow flows. The method comprises generating a cleaning airflow at the dirty side of the filter, the cleaning airflow having a predetermined volume and pressure, and generating an extraction airflow to extract from the filter housing the same volume and pressure of air from the filter housing as that generated in the filter housing by the cleaning airflow.

The invention relates to a decake apparatus. The decake apparatus has a chamber with a base to support a build cake. The build cake includes a build object and non-solidified build material. The apparatus includes a distributor from which to force a fluidisation medium into a lower portion of a build cake supported on the base to fluidise non-solidified build material around the build object so that the build object sinks through the fluidised non-solidified build material towards the base. The also includes a material outlet through which non-solidified build material can be removed from the chamber.

The invention relates to a decake apparatus. The decake apparatus has a chamber with a base to support a build cake. The build cake includes a build object and non-solidified build material. The apparatus includes a distributor from which to force a fluidisation medium into a lower portion of a build cake supported on the base to fluidise non-solidified build material around the build object so that the build object sinks through the fluidised non-solidified build material towards the base. The also includes a material outlet through which non-solidified build material can be removed from the chamber.

The present disclosure generally relates to methods for additive manufacturing (AM) for fabricating multi-walled structures. A multi-walled structure includes a first wall having a first surface and a second wall having a second surface facing the first surface to define a passage having a width between the first surface and the second surface in a first direction. The multi-walled structure also includes an enlarged powder removal feature connecting the first wall and the second wall. The enlarged powder removal feature has an inner dimension greater than the width in the first direction and at least one open end in a direction transverse to the first width.

Techniques for depowdering additively fabricated parts are described in which powder is separated from parts by creating a large pressure differential between the powder and parts and a nearby location. The pressure differential may cause gas to quickly flow into and/or around the powder and parts, thereby producing a force against the powder and parts. Since the powder is generally much lighter than the parts, this force may be much more effective at moving the powder than moving the parts. As a result, the powder and parts may be separated from one another. The pressure differential may be created in various ways, such as by holding the parts and part in a chamber that is pressurized with air and/or other gas(es). Rapid depressurization of the chamber may produce the aforementioned pressure differential, leading to powder movement away from the parts.

Techniques for depowdering additively fabricated parts are described in which powder is separated from parts by creating a large pressure differential between the powder and parts and a nearby location. The pressure differential may cause gas to quickly flow into and/or around the powder and parts, thereby producing a force against the powder and parts. Since the powder is generally much lighter than the parts, this force may be much more effective at moving the powder than moving the parts. As a result, the powder and parts may be separated from one another. The pressure differential may be created in various ways, such as by holding the parts and part in a chamber that is pressurized with air and/or other gas(es). Rapid depressurization of the chamber may produce the aforementioned pressure differential, leading to powder movement away from the parts.

A method of constructing a heat exchanger includes providing a base, and additively manufacturing a plurality of first walls substantially parallel and substantially vertical while being manufactured, wherein the plurality of first walls are spaced apart and attached to the base. The method also includes removing at least a portion of a build powder located between the plurality of first walls and attaching a parting sheet to the plurality of first walls. The method also includes additively manufacturing a plurality of second walls substantially parallel and substantially vertical while being manufactured and are spaced apart.