Abstract: An additive manufacturing apparatus includes an environmentally sealed first chamber, a second chamber separated from the first chamber by a first valve, a platform positionable in the first chamber, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform in the first chamber, at least one energy source to selectively fuse feed material in a layer on the platform in the first chamber, and an air knife assembly to direct a laminar flow of air across a layer of feed material on the platform in the first chamber. The air knife assembly includes an inlet module and an exhaust module that are movable through the first valve between the first chamber and the second chamber.

Abstract: An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife assembly. The air knife assembly includes an inlet unit to deliver gas over the platform and an exhaust unit to receive gas from over the platform. The exhaust unit includes a plenum having a port connected to a gas return conduit, and a gas collector that is open at a front end to receive gas from over the platform and has a concave plate at a back end of the gas collector. An aperture is formed at a back of the concave plate between the gas collector and the plenum to provide a constricted flow path for gas from the collector to the plenum.

Abstract: An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife assembly. The air knife assembly includes an inlet unit to deliver gas over the platform and an exhaust unit to receive gas from over the platform. The inlet unit includes a multi-chamber plenum, a gas inlet, and a gas distribution module. The multi-chamber plenum has a plurality of vertically stacked chambers that are fluidically connected, with a first chamber of the plurality of vertically stacked chambers positioned at a higher elevation than a collection chamber of the plurality of vertically stacked chambers.

Abstract: An additive manufacturing apparatus includes an environmentally sealed first chamber, a second chamber separated from the first chamber by a first valve, a platform positionable in the first chamber, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform in the first chamber, at least one energy source to selectively fuse feed material in a layer on the platform in the first chamber, and an air knife assembly to direct a laminar flow of air across a layer of feed material on the platform in the first chamber. The air knife assembly includes an inlet module and an exhaust module that are movable through the first valve between the first chamber and the second chamber.

Abstract: An additive manufacturing apparatus includes an environmentally sealed first chamber, a second chamber separated from the first chamber by a first valve, a platform positionable in the first chamber, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform in the first chamber, at least one energy source to selectively fuse feed material in a layer on the platform in the first chamber, and an air knife assembly to direct a laminar flow of air across a layer of feed material on the platform in the first chamber. The air knife assembly includes an inlet module and an exhaust module that are movable through the first valve between the first chamber and the second chamber.

Abstract: An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material onto the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife assembly. The air knife assembly includes an inlet unit to deliver gas over the platform and an exhaust unit to receive gas from over the platform. The inlet unit includes a multi-chamber plenum, a gas inlet, and a gas distribution module. The multi-chamber plenum has a plurality of vertically stacked chambers that are fluidically connected, with a first chamber of the plurality of vertically stacked chambers positioned at a higher elevation than a collection chamber of the plurality of vertically stacked chambers.