Energy beam casting of metal articles
First Claim
1. A method of producing articles from powder metal comprising the steps of:
- generating a focused energy beam having an energy density sufficient to melt the powder metal;
generating relative movement between the energy beam and a substrate such that the energy beam repetitively traces over the substrate the shape of said article and melts the surface of the substrate at the interface of the energy beam and the substrate; and
feeding powder metal onto said substrate to maintain a depth of powder metal which laterally supports and forms a mold for a layer of powder metal at the energy beam interface which is melted by the energy beam, the thickness of the layer of powder metal being such that the energy beam penetrates the layer of powder metal and melts the surface of the substrate but only to the extent to wet the substrate sufficiently to bond to the substrate the melted powder metal, which in turn, cools rapidly upon leaving the energy beam interface to form a thick layer of the article which becomes the substrate for the next layer.
2 Assignments
0 Petitions
Accused Products
Abstract
Near net shape metal articles are cast from powder feedstock using a focused high energy beam which melts successive layers of powder as it repetitively traces the shape of the article over a substrate without the necessity for refocusing. Powder is fed into a cavity in which the article is formed at a rate to maintain a depth which provides lateral support for, and therefore forms a mold for, a thick layer of powder which is melted by the energy beam to add each layer to the article. The high energy laser or electron beam has a power density sufficient to penetrate the melted layer of powder and melt the surface of the underlying substrate or layer just enough to provide a good metallurgical bond for the layer being added. A copper fixture which supports the substrate while the article is being formed, serves as a heat sink and forms the cavity which confines the powder to the vicinity of the article being formed. Various shapes can be cast through selected programming of the repetitive pattern of relative motion between the energy beam and the substrate.
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Citations
14 Claims
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1. A method of producing articles from powder metal comprising the steps of:
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generating a focused energy beam having an energy density sufficient to melt the powder metal; generating relative movement between the energy beam and a substrate such that the energy beam repetitively traces over the substrate the shape of said article and melts the surface of the substrate at the interface of the energy beam and the substrate; and feeding powder metal onto said substrate to maintain a depth of powder metal which laterally supports and forms a mold for a layer of powder metal at the energy beam interface which is melted by the energy beam, the thickness of the layer of powder metal being such that the energy beam penetrates the layer of powder metal and melts the surface of the substrate but only to the extent to wet the substrate sufficiently to bond to the substrate the melted powder metal, which in turn, cools rapidly upon leaving the energy beam interface to form a thick layer of the article which becomes the substrate for the next layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. Apparatus for forming articles from powder metal comprising:
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means for generating a focused energy beam having an energy density sufficient to melt the powder metal; a base substrate; means for generating relative movement between the energy beam and the base substrate such that the interface of the energy beam with the base substrate repetitively traces the shape of said article over said base substrate; a guide member supported between the energy beam generating means and the base substrate and forming with the base substrate a cavity in which said article is formed; and means for feeding powder metal into said cavity to maintain a depth of powder metal in the cavity which laterally supports and forms a mold for a layer of powder metal at the energy beam interface which is melted by the energy beam, the thickness of the layer of powder metal being such that the energy beam penetrates the layer of powder metal and melts the surface of the base substrate, but only to the extent to wet the substrate sufficiently to bond to the substrate the melted powder metal, which in turn, cools rapidly upon leaving the energy beam interface to form a thick layer of the article which becomes the substrate for the next layer. - View Dependent Claims (14)
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Specification