144 Early Laser Structural Shape Making Techniques

Researchers developing laser materials processing technology also experimented with the fabrication of structural components by the successive buildup of layers completely melted and fused to the previous layer. One such process [9] involved using a laser to fuse added powder or wire on a rotating mandrel. Successive layers were built and found to be of high metallurgical quality. Graded compositions were also produced. In another process [10] a laser was used to melt and fuse layers of powder that was predeposited on the substrate or previous layer by means of a fluidized bed. The process was used to form crude titanium shapes. Neither of the previous two patents, however, discussed the method by which the shape would be generated from electronic data. In a third process [11] a laser was used to completely melt and fuse added powder to a substrate or previous layer using a computer-controlled machine with electronic data representing "slices" of the component being built. Examples of laser depositing of Ti-6Al-4V and alloy 718 were provided. However, all of these "early" efforts in making structural shapes using laser deposition technology did not demonstrate the complex shape-making capability that has been the signature of modern rapid prototyping technologies discussed above.

Only after the merger of these two independent technologies is it possible to claim that rapid manufacturing of structural metal components is possible.

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