US Patent 7073561 Solid freeform fabrication system and method

A system and method of solid freeform work piece fabrication through layered deposition of feedstock material on a mold structure. An energy beam and feedstock are fed to a feed point adjacent to a mold structure, thereby forming a molten puddle. The feed point is moved relative to the mold structure, thereby advancing the molten puddle of presently fed feedstock and rapidly solidifying previously fed feedstock. The feed point is sequentially advanced within a predetermined geometric volume containing at least a portion of the mold structure, thereby sequentially fusing the feedstock, by action of the advancing molten puddle, into a near net shape work piece built-up upon the mold structure.