Patent ID: 8598523

Claim:
A process for layer manufacturing a three-dimensional work piece comprising the steps of: (a) feeding raw material in a solid state to a first predetermined location; (b) exposing the raw material to an electron beam to liquefy the raw material; (c) depositing the raw material onto a substrate as a molten pool deposit, the deposit having a forward edge region in an x-y plane with a forward edge region width and a trailing edge region in the x-y plane with a trailing edge region width, under at least one first processing condition; (d) monitoring the molten pool deposit for at least one preselected condition, using one or more detectors; (e) detecting scatter from a scanning electron beam, using one of the one or more detectors, contemporaneously with the depositing step, optionally using a detector that is in a housing configured so that the detector detects electrons of a preselected characteristic; (f) monitoring a distance of an electron beam generating device to a three-dimensional work piece, using the one or more detectors, during build-up of the three-dimensional work piece, and altering a processing condition based upon detection of a distortion in a z-axis; (g) solidifying the molten pool deposit; (h) automatically altering the first processing condition to a different processing condition based upon information obtained from the step of detecting scatter (e); and (i) repeating steps (a) through (h) at one or more second locations for building up layer by layer, generally along the z-axis that is orthogonal to the x-y plane, the three-dimensional work piece; wherein during consecutive steps of exposing and monitoring the same electron beam is employed for both operations so that scanning electron beam is a beam emitted from an electron beam generating device that also emits the electron beam to liquefy the raw material; wherein the scanning electron beam is consecutively switched back and forth between a first condition for melting and a second condition for monitoring at a rate of at least 5 times per second; and wherein the electron beam, the one or more detectors, and the three-dimensional work piece are enclosed in a chamber.