Patents by Inventor Daniel S. Gnanamuthu
Daniel S. Gnanamuthu has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 4990741Abstract: First and second metallic components are joined along a weld path by providing a beam of coherent electromagnetic energy having sufficient power to melt the first and second components and providing a low turbulent flow of an inert shielding gas over a weld region along a portion of the weld path. The beam is focussed on the weld region such that the beam energy is linearly distributed in the direction of the weld path with an intensity sufficient to form a pool of molten metal in the weld region. Relative motion is then established between the components and the beam to cause the weld region to move along the weld path, thereby joining the first and second components along the weld path.Type: GrantFiled: February 6, 1990Date of Patent: February 5, 1991Assignee: Rockwell International CorporationInventors: Ralph J. Moores, Daniel S. Gnanamuthu
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Patent number: 4716270Abstract: A method is disclosed for scribing chemical milling maskant applied to a metal substrate by impinging a laser beam on the maskant and controlling the beam to penetrate through the maskant substantially without damaging the underlying metal. In carrying out the process, a metal part such as aluminum, titanium or their alloys is coated with an organic polymer maskant having absorption to a laser beam, a predetermined pattern is scribed in the maskant by impinging a laser beam, e.g. a Nd:YAG (neodymium doped yttrium aluminum garnet) laser, under controlled conditions to scribe a predetermined pattern in the maskant and substantially without damaging the underlying metal, removing the maskant portion within the circumscribed area of the pattern to expose the underlying metal and leaving the remaining maskant portion adhered to the substrate, immersing the metal substrate in a chemical milling solution, e.g.Type: GrantFiled: November 4, 1985Date of Patent: December 29, 1987Assignee: Rockwell International CorporationInventors: Daniel S. Gnanamuthu, Ralph J. Moores, Neil E. Paton, Richard F. Vyhna
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Patent number: 4401726Abstract: Properties of the surface of low melting substrate parts including low melting, high conductivity reactive metal parts, are modified by forming an alloy casing thereon having the metal of the substrate as a first (matrix) component thereof together with a higher melting material as the second (reinforcing) component. The higher melting component is coated on the substrate, melted under laser heating, with gas shielding to avoid oxidation, and mixed with a melted portion of the substrate through convective circulation and the mixture is rapidly cooled to produce the alloy casing. Then the casing may be rescanned with the laser beam to rapidly melt and resolidify the casing with refined grain structure. Such grain refining may also be applied to uncoated substrates.Type: GrantFiled: December 21, 1981Date of Patent: August 30, 1983Assignee: Avco Everett Research Laboratory, Inc.Inventor: Daniel S. Gnanamuthu
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Patent number: 4015100Abstract: Properties of a surface layer of a metal part are modified by changing its composition and microstructure using focused radiant energy. Minor components of an alloy having the metal of the substrate as the major component thereof are applied to the surface and a limited depth surface layer of the substrate metal is melted, the coated-on components are mixed therewith and the mixture is rapidly cooled to produce a desired surfacing alloy to a controlled depth within the substrate and having a fine grained microstructure compared to the microstructure of the substrate metal. The amount of coated-on minor alloy components and the preselected depth of melting of the substrate metal provide alloy composition control.Type: GrantFiled: September 8, 1975Date of Patent: March 29, 1977Assignee: Avco Everett Research Laboratory, Inc.Inventors: Daniel S. Gnanamuthu, Edward V. Locke
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Patent number: 3952180Abstract: A metal layer is clad to a metal substrate by laying spaced rods or wires of a cladding metal on the substrate surface and scanning the cladding metal with a continuously operating laser beam, part of which impinges directly on the cladding metal to melt it and part of which impinges on the adjacent surface area of the substrate to improve flow of molten metal thereon. The cladding metal may be fed to the substrate surface in synchronism with laser beam scanning. The process produces a clad layer of the cladding metal on the substrate characterized by a fine and homogeneous structure within the clad on layer and further characterized by uniform and high hardness compared to prior art cladding methods. The surface of the clad may be smoothed by locally oscillating the laser beam during the course of cladding and/or by multiple passes.Type: GrantFiled: December 4, 1974Date of Patent: April 20, 1976Assignee: Avco Everett Research Laboratory, Inc.Inventor: Daniel S. Gnanamuthu
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Patent number: RE29815Abstract: A metal layer is clad to a metal substrate by laying spaced rods or wires of a cladding metal on the substrate surface and scanning the cladding metal with a continuously operating laser beam, part of which impinges directly on the cladding metal to melt it and part of which impinges on the adjacent surface area of the substrate to improve flow of molten metal thereon. The cladding metal may be fed to the substrate surface in synchronism with laser beam scanning. The process produces a clad layer of the cladding metal on the substrate characterized by a fine and homogeneous structure within the clad on layer and further characterized by uniform and high hardness compared to prior art cladding methods. The surface of the clad may be smoothed by locally oscillating the laser beam during the course of cladding and/or by multiple passes.Type: GrantFiled: June 15, 1977Date of Patent: October 24, 1978Assignee: Avco Everett Research Laboratory, Inc.Inventor: Daniel S. Gnanamuthu