In-process surface finishing for unitized additive structures

An abrasive flow machining (AFM) system comprising:

• a first abrasive media reservoir;
• means for connecting the first abrasive media reservoir to an additive manufacturing (AM) system build plate, wherein the AM system build plate includes a structure built on the AM system build plate during an AM system build campaign and a plurality of abrasive media flow channels extending entirely through a thickness of the AM system build plate;
• and
• means for directing abrasive media from the first abrasive media reservoir through the plurality of abrasive media flow channels in the AM system build plate into a plurality of flow channels in the structure.

A method of making a structure with a powder bed fusion (PBF) additive manufacturing (AM) system, comprising:

• installing in the AM system a build plate configured to support a structure built on the build plate during a PBF build campaign, wherein the build plate includes a plurality abrasive media flow channels extending entirely through a thickness of the build plate;
• wherein the plurality of abrasive media flow channels are configured and sized to be open during an abrasive flow machining (AFM) operation to permit a flow of abrasive media from a source of abrasive media to the structure positioned on the build plate;
• delivering, with a powder delivery mechanism, build powder to a build area to form a build powder bed;
• distributing, with a recoater, the build powder in the build powder bed to provide even distribution of the build powder in the build powder bed;
• directing energy, from an optical array positioned over the build area on the build plate, to the build powder in the build powder bed to form a melt pool in the build powder bed;
• selectively sintering, using energy from the optical array, build powder from the melt pool to form a layer of the structure on the build plate;
• and
• lowering the build plate, with a build piston, at a predetermined rate as the structure is formed on the build plate during the PBF campaign;
• pausing the PBF build campaign at a predetermined point, wherein the predetermined point corresponds to completion of desired elements of the structure;
• evacuating from the AM system unconsolidated build powder;
• elevating the build plate, with the build piston, to permit the build plate and the structure built on the build plate to be removed from the AM system;
• removing the build plate and the structure built on the build plate from the AM system;
• positioning the build plate and the structure built on the build plate in an abrasive flow system;
• flowing, with the abrasive flow system, abrasive material from a first abrasive media reservoir on the abrasive flow system through the abrasive media flow channels in the build plate and through a plurality of flow channels in the structure to achieve a desired surface finish on the plurality of flow channels in the structure;
• removing the build plate and the structure built on the build plate from the abrasive flow system;
• positioning the build plate and the structure built on the build plate in the AM system;
• lowering the build plate and the structure built on the build plate to a predetermined height, wherein the predetermined height corresponds to the height at which the PBF campaign was paused;
• and
• restarting the PBF campaign by:
• delivering, with the powder delivery mechanism, build powder to the build area over the build plate and surrounding the structure built on the build plate to re-form the build powder bed;
• distributing, with a recoater, the build powder in the build powder bed to provide even distribution of the build powder in the build powder bed;
• directing energy, from the optical array positioned over the build area on the build plate, to the build powder in the build powder bed to re-form the melt pool in the build powder bed;
• and
• selectively sintering, using energy from the optical array, build powder from the melt pool to form another layer of the structure on the build plate.