摘要：
A process and apparatus for perfoming the process for layer manufacturing a three-dimensional work piece comprising the steps of feeding raw material in a solid state to a first predetermined location; exposing the raw material to an electron beam (12) to liquefy the raw material; depositing the raw material onto a substrate (16) 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; monitoring the molten pool deposit for at least one preselected condition using detecting of scatter from a scanning electron beam (12) contemporaneously with the depositing step; solidifying the molten pool deposit; automatically altering the first processing condition to a different processing condition based upon information obtained from the comparing step; and repeating steps 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, a three-dimensional work piece.
技术问题语段：
This approach may pose potential for complications due to the subjectivity of the observations of the operator, due to any delay experienced between an observation and any adjustment in operating parameters, and/or due to improper selection of parameters.|This is a particularly acute difficulty when attempting to conduct LM at relatively high output rates.
技术功效语段：
[0012] The present invention seeks to improve upon prior LM apparatus and processes by providing a unique process and apparatus for fabrication of articles utilizing the same component, namely an electron beam generator, to perform the functions of melting metal for deposit and scanning for substantially contemporaneously monitoring the condition of a resulting melt deposit as part of a closed loop control system. The invention makesadvantageous use of one or more unique features for allowing rapid article builds, especially aided by use of detection of one or more electron phenomena that occurs from emission from the electron beam generator and interaction with a mett pool deposit.
权利要求：
CLAIMS
1. 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 traling 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, such as width, using detecting of scatter from a scanning electron beam
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;
(e) solidifying the molten pool deposit;
(f) automatically altering the first processing condition to a different processing
condition based upon information obtained from the monitoring step (d); and
(g) repeating steps (a) through (f) at one or more second locations for building up layer by layer, generally along a z-axfs that is orthogonal to the x-y plane, a three-dimensional work piece.
2. The process of claim 1. wherein the scanning electron beam is a beam emitted from an electron beam generating device that also emits the electron beam to liquefy the raw material.
3. The process of claim 1 or 2, 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.
4. The process of any of dakns 1 through 3. wherein the monitoring step indudes detecting electrons scattered in the region proximate the molten pool deposit during build-up of the work piece.
5. The process of any of claims 1 through 4, wherein the monitoring step Includes detecting electrons scattered in the region proximate the molten pool deposit during build-up of the work piece, by use of at least one detector that detects data from at least about 4000 beam deflection location points on a target.
6. The process of any of claims 1 through 5, wherein the monitoring step includes detecting electrons scattered in the region proximate the molten pool deposit during build-up of the work piece, by use of at least one detecting device encased in a cavity of a housing and accessible via a port of the housing.
7. The process of any of claims 1 through 5 wherein the monitoring step includes detecting electrons scattered in the region proximate the molten pool deposit during buBd-up of the work piece, by use of at least one device that includes a shielded detector housing and that selectively excludes from the housing electrons having a predetermined energy level to prevent their detection by a detector carried in the housing.
8. The process of any of claims 1 through 7, wherein the scanning electron beam is maintained at a power level greater than about 500 watts during the monitoring step.
9. The process of any of claims 1 through 8, wherein the scanning electron beam is maintained at a substantially constant width for a period during consecutive steps of exposing and monitoring.
10. The process of claims 1 through 9, wherein the scanning electron beam is a beam emitted from an electron beam generating device that also emits the electron beam to fiquefy the raw material.
11. The process of any of claims 1 through 10, wherein during consecutive steps of exposing and monitoring, the same beam is employed for both operations.
12. The process of claim 11 , wherein during consecutive steps of exposing and monitoring, the beam is rastered according to a predetermined pattern.
13. The process of claim 12, wherein one or more deflection coils raster the beam.
14. The process of any of claims 1 through 13, wherein the at least one preselected condition Indudes the trailing edge region width of the molten pool deposit or otherwise upstream of the feed of raw material.
15. The process of any of claimsl through 14, wherein the at least one presetected condition indudes the width of the molten pool deposit, and wherein (i) upon detection of a width that exceeds a certain predetermined value, the power of the beam is reduced, (ii) upon detection of a width that is below a certain predetermined valu the power of the beam is increased, or both (i) and (ii).
16. The process of any of claims 1 through 14, wherein the monitoring step also Indudes a step of monitoring the distance of an electron beam generating device to the work piece during build-up of the work piece, and altering a processing condition based upon detection of a distortion in the z-axfs.
17. The process of claim 16, wherein the step of monitoring the distance of an electron beam generating device to the work piece Includes a step of detecting by monitoring, a laser beam, by optical image monitoring, electron beam scanning detection, or both.
18. The process of claim 17, wherein the step of monitoring the distance of an electron beam generating device to the work piece includes a step of triangulating the distance.
19. The process of claim 15, wherein the step of monitoring the distance of an electron beam generating device to the work piece includes detection by optical image monitoring with a digital camera that includes a vapor protection device, a thermally regulated housing or both.
20. The process of any of claims 1 through 17, wherein the monitoring is free of any step of generating an image from scattered electrons.
21. The process of any of claims 1 through 20, wherein the same electron beam generating device is employed to generate the electron beam and the scanning electron beam, the step of automatically altering Is performed by at least one control device that is in electrical signaling communication with the electron beam gun, and wherein during the monitoring a detection signal that is transmitted to the at least one control device upon detection of scatter and which is indicative of a characteristic of the scatter, the detection signal information from the signal is compared with a predetermined value, and based upon such comparison the control device issues a control signal to the electron beam generating device.
22. The process of any of claims 1 through 21 , wherein the electron beam generating device is translated during work-piece build up relative to a fixed position for the workpiece.
23. An apparatus that performs the process of any of claims 1 through 22.
24. An article made using the process of any of claims 1 through 22.
25. The article of claim 23, wherein the artide is an aircraft component, a rocket component, a marine craft component, a raHcar component an automotive vehicle component, a chemical processing component, a turbine component or a space vehide component; and wherein the artide is metalk