Patent attributes
An additive manufacturing apparatus includes a platform, a dispenser configured to deliver a plurality of successive layers of feed material on the platform, at least one energy source to selectively fuse feed material in a layer on the platform, and an air knife supply unit. The air knife supply unit includes a tube having a plurality of holes spaced along a length of the tube, a multi-fluted helical screw positioned in the tube, a gas inlet configured to supply a gas into an end of the tube with the screw configured to guide the gas from the gas inlet through the tube and out the holes, and a spiral plenum surrounding the tube with the spiral plenum including an inner end to receive gas from the holes and an outer end to deliver the gas over the platform.
