Raster methodology, apparatus and system for electron beam layer manufacturing using closed loop control

A method for layer-by-layer manufacturing of a three-dimensional metallic work piece, comprising the steps of:

• a) delivering a metallic feed material in a substantially solid state into a feed region;
• b) emitting an electron beam having one or more predetermined electrical currents;
• c) translating the electron beam through a first predetermined raster pattern frame in an x-y plane that includes:
• (i) a plurality of points within the feed region so that the metallic feed material is subjected to a melting beam power density level sufficient to cause melting of the metallic feed material and formation of a molten pool deposit;
• and
• (ii) a plurality of points in a substrate region that is outside of the feed region, so that the plurality of points outside the feed region is subjected to a substrate beam power density level that is different from the melting beam power density level, and wherein the substrate region generally surrounds the feed region;
• d) monitoring a condition of one or both of the feed region or the substrate region substantially in real time for any occurrence of any deviation from a predetermined condition;
• e) upon detecting of any deviation, the substrate beam power density level, a feed rate of the feed material, a location of a material delivery device, or a combination thereof are altered in a manner so that the monitored condition returns to the predetermined condition;
• and
• f) repeating steps (a) through (e) at one or more second locations for building up layer by layer, generally along a z-axis that is orthogonal to the x-y plane, the three-dimensional layered metallic work piece.