Forming structures from CAD solid models

DETAILED DESCRIPTION The present invention pertains generally to a class of material deposition processes that use a laser to heat and, subsequently, fuse powder materials into solid layers.
Since these layers can be deposited in sequential fashion to ultimately form a solid object, the ability to alter the material properties in a very localized fashion has far reaching implications.
The present invention comprises apparatus and method for fabrication of metallic hardware with exceptional material properties and good dimensional repeatability.
The invention provides a method for controlling material composition, and thus material characteristics, within a structure made from a plurality of materials, directly from computer renderings of solid models of the desired component.
Both industry-accepted stereolithography (STL) file format as well as solid model file format are usable.
One embodiment of the invention is used to form embedded features in a three-dimensional structure.
A plurality of separate material feedstock are fed into a directed material deposition (DMD) process which places a line of molten material onto a substrate.
The depositions are repeated in a layer-by-layer pattern, defined by solid models which describe the structure, to create an article having complex geometric details.
The bulk properties of the deposition are controlled by adjusting the ratio of laser irradiance to laser velocity along the line of deposition.
In addition to external contours, the solid-model computer files describe regions of each separate material, regions of a composite of the materials and regions of voids in each layer or "slice.
" The depositions are repeated in each of the "slices" of the solid models to create the geometric details within the three-dimensional structure.
Heating the substrate and the deposition produces parts with accurate dimensions by eliminating warping of the substrate and deposition.
A prescribed temperature profile is used for processing tempered material.
A temperature profile for heat treating may be used to enhance the mechanical properties of the part by ensuring the correct material microstructure during processing