The University of Texas System

Other

Motorola Corporation

USA As Represented by Secretary of the Navy

Harris L Marcus

Joel W Barlow

David L Bourell

Joseph Jefferson Beaman, Jr

Carl Robert Deckard

Richard H Crawford

Richard J Lagow

Goonhee Lee

Udaykumar Lakshminarayan

James V Tompkins

Britton R Birmingham

Kent M Blumenshine

Kathleen A Long-Daugherty

Guisheng Zong

James C Fletcher

Arumugam Manthiram

Neal K Vail

Morris E Fine

Kevin J Jakubenas

Wendy L Weiss

Zwy Eliezer

Shyh-Nung Lin

Joseph L Beaman

James R Tobin

Balasubramanian Badrinarayan

Phillip J Stocker

W Richards Thissell

A process for making bone implants from calcium phosphate powders is disclosed. This process involves selectively fusing layers of calcium powders that have been coated or mixed with polymer binders. The calcium powder mixture may be formed into layers and the polymer fused with a laser. Complex three-dimensional geometrical shapes can be automatically replicated or modified using this approach.

Artificial bone implants

A mold useful for injection molding, comprising: a porous network of metal and oxidized metal and a cured epoxy resin dispersed in the porous network. The mold can be prepared by a process comprising the sequential steps of (a) forming a mixture of a metal powder and a polymer binder; (b) heating the mixture at a temperature in the range from about 100.degree. C. to about 300.degree. C. to remove a majority of the polymer binder from the mixture; (c) heating the mixture resulting from step (b) at a temperature greater than about 300.degree. C. and less than the melting point of the metal in the presence of oxygen to oxidize at least a portion of the metal to form a self-adhering porous network of metal and oxidized metal; (d) contacting the self-adhering porous network with an epoxy resin to fill at least a portion of the porous network with epoxy resin; and (e) curing the body resulting from step (d) to form the mold. The shape of the mold can be performed by selective laser sintering of the mixture.

Mold useful for injection molding of plastics, and methods of production

Bone implants are made from calcium phosphate powders by selectively fusing layers of calcium powders that have been coated or mixed with polymer binders. The calcium powder mixture may be formed into layers and the polymer fused with a laser. Complex three-dimensional geometrical shapes can be automatically replicated or modified using this approach.

Method for fabricating artificial bone implant green parts

A process for joining solid compositions, comprising placing a first solid composition having a first joining zone and a second solid composition having a second joining zone in a chamber; positioning a first gas phase, which comprises a substance that decomposes to a material that adheres to the first and second solid compositions during the process, proximate the target area; directing an energy beam to the first and second joining zones to selectively deposit material from the first gas phase on the first joining zone and the second joining zone until a joint is formed between the first and second solid compositions wherein the joint adheres to the first and second compositions at the first and second joining zones. A process useful for attaching a solid fastener to a solid composition, comprising: placing the solid composition in a chamber; positioning a first gas phase, which comprises a substance that decomposes to a material that adheres to the solid composition during the process, proximate the solid composition; directing at least one energy beam to the solid composition to selectively deposit material from the first gas phase on the solid composition to form the solid fastener attached to the solid composition. The invention can also be used to repair solid compositions which contain defects such as chips or cracks or to modify the preexisting shape by localized addition of material from the gas phase.

Joining ceramics and attaching fasteners to ceramics by gas phase

A method of fabricating three-dimensional objects in a layerwise fashion, and having high structural strength and high density, is disclosed. Methods are disclosed by which nanocomposite powders of ceramic-ceramic systems, ceramic-metal systems, ceramic-polymer systems, and metal-polymer systems are produced. Disclosed examples utilize solution chemistry approaches, such as sol-gel processing, by way of which a gel is produced which is then fired and milled to form a powder suitable for selective laser sintering, where a laser fuses selected portions of layers of the powders according to a computer-aided-design data base. The ultraheterogeneity of the powder results in larger surface area and grain boundaries of the constituents, which enhances the solid state diffusion mechanism, and thus reduces the time and temperature required for sintering to occur. In addition, the higher stored metastable energy of the nanocomposite powder is believed to enhance densification during solid-phase sintering. Objects of high density of complex shape may thus be obtained directly from CAD data base design representations.

Selective laser sintering using nanocomposite materials

A method and apparatus for selectively sintering a layer of powder to produce a part comprising a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto the powder to produce a sintered mass. The computer either determines or is programmed with the boundaries of the desired cross-sectional regions of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section. Powder is applied and successive layers sintered until a completed part is formed. Preferably, the powder comprises a plurality of materials having different dissociation or bonding temperatures. The powder preferably comprises blended or coated materials.

Multiple material systems for selective beam sintering

A process for forming a copper alloy which is strengthened while maintaining good electrical and thermal conductivity by the addition of TiN or ZrN consists of external nitridation of a mechanically alloyed powder mixture followed by further mechanical alloying to break down the surface coating which forms during nitridation.

Method of making copper-titanium nitride alloy

Methods and apparatus for selectively depositing a layer of material from a gas phase to produce a part comprising a plurality of deposited layers. The apparatus includes a computer controlling a directed energy beam, such as a laser, to direct the laser energy into an unheated chamber substantially containing the gas phase to preferably produce photodecomposition or thermal decomposition of the gas phase and selectively deposit material within the boundaries of the desired cross-sectional regions of the part. At least one component of the gas phase is a vapor which condenses at a temperature above the ambient temperature of the chamber. Each such component can exist at a partial pressure no higher than its equilibrium vapor pressure at the chamber ambient temperature. For each cross section, the aim of the laser beam is scanned over a target area and the beam is switched on to deposit material within the boundaries of the cross-section. Each subsequent layer is joined to the immediately preceding layer to produce a part comprising a plurality of joined layers. A catalytic environment can be created proximate or upon the target area to ensure that initial nucleation and renucleation layers are receptive to substantially rapid and uniform growth of decomposed gas phase material at the target location. The catalyst can be placed on the initial substrate layer and/or upon successive layers as the layers are being deposited on the outer surface of the evolving part.

Method and apparatus for direct use of low pressure vapor from liquid or

A method and apparatus for selectively sintering a layer of powder to produce a part comprising a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto each layer of the powder to produce a sintered mass corresponding to a cross-section of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section. Powder is applied and successive layers sintered until a completed part is formed. Also disclosed is a method of forming a part by interaction of material in the powder layer with reactants in the surrounding atmosphere, at locations of the powder irradiated by the energy, or laser, beam. The reaction may be nitridation, oxidation or carburization of the powder, with the product being a chemical compound of one or more constituents in the powder with one or more gases in the atmosphere. Alternatively, reduction of the powder may be so enabled by the energy beam so that a metallic phase product is formed at the irradiated locations. Particular benefits of the invention include the densification of the material of the part as a result of the reaction, and the ability to form high temperature materials by way of a relatively low temperature process.

Method of producing parts by selective beam interaction of powder with

A method and apparatus for selectively depositing a layer of material from a gas phase to produce a part comprising a plurality of deposited layers. The apparatus includes a computer controlling a directed energy beam, such as a laser, to direct the laser energy into a chamber substantially containing the gas phase to preferably produce photodecomposition or thermal decomposition of the gas phase and selectively deposit material within the boundaries of the desired cross-sectional regions of the part. For each cross section, the aim of the laser beam is scanned over a target area and the beam is switched on to deposit material within the boundaries of the cross-section. Each subsequent layer is joined to the immediately preceding layer to produce a part comprising a plurality of joined layers. In an alternate embodiment of the present invention, a gas phase is condensed on a surface and a laser beam is used to selectively evaporate, transform, activate or decompose material in each layer. A catalytic environment can be created proximate or upon the target area to ensure that initial nucleation and renucleation layers are receptive to substantially rapid and uniform growth of gas phase material at the target location. The catalyst can be placed on the initial substrate layer and/or upon successive layers as the layers are being deposited on the outer surface of the evolving part.

Catalyst and plasma assisted nucleation and renucleation of gas phase

A method and apparatus for selectively sintering a layer of powder to produce a part comprising a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto the powder to produce a sintered mass. The computer either determines or is programmed with the boundaries of the desired cross-sectional regions of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section. Powder is applied and successive layers sintered until a completed part is formed. Preferably, the powder comprises a plurality of materials having different dissociation or bonding temperatures. The powder preferably comprises blended or coated materials, including precursor materials which are formed into a mass at the irradiated locations, and which either react due to the laser thermal energy or in a later heat treatment to form a compound with properties different than the precursors. Examples are disclosed wherein a compound is formed which has a significantly higher melting point than that of one or more of the precursor powders.

Selective laser sintering of parts by compound formation of precursor

A method and apparatus for selectively sintering a layer of powder to produce a part comprising a plurality of sintered layers. The apparatus includes a computer controlling a laser to direct the laser energy onto the powder to produce a sintered mass. The computer either determines or is programmed with the boundaries of the desired cross-sectional regions of the part. For each cross-section, the aim of the laser beam is scanned over a layer of powder and the beam is switched on to sinter only the powder within the boundaries of the cross-section. Powder is applied and successive layers sintered until a completed part is formed. Preferably, the powder comprises a plurality of materials having different dissociation or bonding temperatures. The powder preferably comprises blended or coated materials, including precursor materials which are formed into a mass at the irradiated locations, and which either react due to the laser thermal energy or in a later heat treatment to form a compound with properties different than the precursors. Examples are disclosed wherein a compound is formed which has a significantly higher melting point than that of one or more of the precursor powders. A ceramic part, such as a mold for investment casting, may be formed according to the method, where a first material (e.g., ammonium dihydrogen phosphate) has a melting point sufficiently low that it is melted so as to bind the second material (e.g., alumina). Subsequent heat treatment enables chemical reaction of the two materials to form a ceramic (e.g., aluminum phosphate) capable of withstanding high temperatures.

Method of producing parts and molds using composite ceramic powders

A method and apparatus for selectively depositing a layer of material from a gas phase to produce a part comprising a plurality of deposited layers. The apparatus includes a computer controlling a directed energy beam, such as a laser, to direct the laser energy into a chamber substantially containing the gas phase to preferably produce photodecomposition or thermal decomposition of the gas phase and selectively deposit material within the boundaries of the desired cross-sectional regions of the part. For each cross section, the aim of the laser beam is scanned over a target area and the beam is switched on to deposit material within the boundaries of the cross-section. Each subsequent layer is joined to the immediately preceding layer to produce a part comprising a plurality of joined layers. In an alternate embodiment of the present invention, a gas phase is condensed on a surface and a laser beam is used to selectively evaporate, transform, activate or decompose material in each layer. The apparatus of the present invention preferably comprises a computer controlled laser generating and scanning system for selectively depositing or evaporating material to produce a part. The present invention further comtemplates an n-degree of freedom positioning apparatus for positioning a target outer layer and a detecting apparatus which can non-intrusively detect the position and thickness of the deposited layer, both of which are close looped into a computer to produce the desired part.

Growing community of inventors

Austin, TX, United States of America

Harris L Marcus