Abstract: Embodiments of a method for increasing the lifetime of a casting slurry are described. One feature of the disclosed embodiments comprises processing refractory materials that are used to form casting slurries to provide a substantial increase in slurry lifetime for slurries made using such processed materials compared to slurries made using materials not processed as described herein. One embodiment of the method comprises heat processing at least one refractory powder. Without limiting the invention to a theory of operation, processing is continued for a period of time sufficient to reduce the amount of hydration from a first hydration level to a second hydration level. A slurry is formed using the refractory powder at a hydration level which provides an increased slurry lifetime relative to the same material without processing according to the disclosed embodiments.

Abstract: A machine for forming and fitting core support pins into wax (70) surrounding a core (68) prior to covering the wax (70) with a frit (76), includes one or more punch devices (30), (82) within its structure, so as to enable the forming of one or more indentations in each pin, intermediate its ends, thereby providing a designed weakness in the pin to cause it to more reliably follow slight relative movement which occurs between the pins and the part being cast, thus reducing stresses in the surface of the part.

Abstract: A ceramic mould slurry is disclosed for forming moulds and metal castings of improved surface quality. The slurry comprises a binder, a gelling agent, a first refractory material having a density of &rgr;1 and a mean particle size of &agr;1, and a second refractory material having a density of &rgr;2 and a mean particle size of &agr;2, wherein &rgr;1>&rgr;2 and &agr;1<&agr;2. The denser refractory material migrates downward through the slurry toward the upward-facing mould surface, thereby allowing formation of a smooth and accurate surface.

Abstract: A method for imaging inclusions in metal or metal alloy castings is described. One embodiment of the present method first involves casting a metal or metal alloy article using an investment casting mold where the mold facecoat, and perhaps one or more of the mold backup layers, comprises an imaging agent distributed substantially uniformly throughout in amounts sufficient for imaging inclusions. The facecoat preferably comprises an intimate mixture of a refractory material and the imaging agent. Intimate mixtures can be produced in a number of ways, but a currently preferred method is to cocalcine the refractory material, such as yttria, with the imaging agent, such as gadolinia. The facecoat also can comprise plural mold-forming materials and/or plural imaging agents. The difference between the linear attenuation coefficient of the article and the linear attenuation coefficient of the imaging agent should be sufficient to allow imaging of the inclusion throughout the article.

Abstract: A compressor wheel is re-designed to permit die inserts (20), which occupy the air passage and define the blades (4, 5) during a process of forming a wax pattern (21) of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns (21) using simplified tooling. These wax patterns (21) can be used in a large-scale investment casting process, and produce an economical cast titanium compressor wheel which performs aerodynamically at high boost pressure/RPM. The compressor wheel improves low cycle fatigue, withstands high temperatures and temperature changes, and permits operation at high boost pressure ratio while, on the other hand, having low weight, low inertial drag, and high responsiveness.

Abstract: Method making a multi-wall ceramic core for use in casting airfoils, such as turbine blades and vanes, wherein a fugitive pattern is formed having multiple thin wall pattern elements providing internal wall-forming spaces of a final core, the pattern is placed in a core molding die cavity having a desired core configuration, a fluid ceramic material is introduced into the die cavity about the pattern and between the pattern elements to form a ceramic core, and the core is removed from the die cavity. The fugitive pattern is selectively removed from the core to provide a multi-wall green core. The green core then is fired to develop core strength for casting and used to form an investment casting mold for casting an airfoil.

Abstract: A method for molding gemstone settings using metal molds is provided. The gemstone settings have unitary seats on the prongs of the settings. The method involves using a core pin mold to form a core pin which is interengageable with a metal production mold for the setting. A gemstone setting is also provided, with a substantially smooth inner prong surface. The gemstone setting provides substantially stronger set gems and reduces the incidences of shattering gems during the setting process.

Abstract: A method of casting a metal article comprising the steps of forming a mold having a mold cavity with a height, a thinwall portion and a base wall portion. The thinwall portion may be less than 0.05 inches thick and free of gating. The method comprises the steps of: positioning the mold in a preheated furnace so that the furnace substantially surrounds the mold and so that a longitudinal axis of the long thin portion of the mold cavity is in an upright orientation; heating the mold in the furnace to a temperature between 1045° C. and 1055° C.; and drawing a vacuum in the furnace. The metal is heated until it is molten and is then poured at a temperature between 1560° land 1570° C. into the mold cavity. The vacuum is then broken and the mold cavity withdrawn from the furnace. The molten metal is allowed to solidify in the mold cavity so that it will solidify with a equiaxed grain structure.

Abstract: An investment casting method using a pattern material with substantially spherical filler particulates is used to produce investment cast components with iproved surface quality, reduced finishing costs, and reduced core breakage. The pattern material comprises substantially spherical particles within the particle size range of about 10 microns to about 70 microns particle diameter, the use of which reduces the number of random, localized surface depressions and pits to improve pattern surface texture and uniformity. Patterns so formed inpart the same improvements to the surface of subsequent investment cast components. The resulting castings exbibit improved as-cast surface finish and reduced random, localized surface pitting, thereby reducing or eliminating expensive post casting surface finishing operations. Moreover, the spherical morphology of the filler particulates reduces injection pressures to fill a pattern die cavity as compared to non-spherical filler particulates.

Abstract: A method of investment casting is disclosed, which comprises the preparation of a refractory slurry by mixing a binder, a refractory material, and a quantity of water-insoluble organic fibres, and the application of one or more coats of this slurry to an expendable pattern, so as to build up a shell. It has been found that each coat of the slurry thus formed is surprisingly thick, and that a relatively short drying time is required for each coat, hence enabling a shell of desirable thickness to be rapidly built in a small number of “dipping cycles”. The invention also encompasses a kit of ingredients for putting the method of the invention into effect; a shell produced in accordance with this method; and a refractory slurry for use in this method.

Abstract: An apparatus and method for forming a hollow golf club head is disclosed. The apparatus includes a first mold cavity having depressions formed therein, a second mold cavity having a shape complementary to the exterior of the desired club head, a ceramic core, and wax injecting means. Each depression of the first mold cavity has a depth equal to a desired wall thickness of a corresponding portion of the club head. When the ceramic core is placed in the first mold cavity and wax is injected, wax protuberances, which correspond to the depressions, are formed about the ceramic core. The wax protuberances position the ceramic core in the second mold cavity, where wax is deposited over the majority of the ceramic core.

Abstract: A fugitive pattern of an article to be investment cast wherein the pattern includes a plurality of locator embossments disposed in an array to provide a datum reference system by which the pattern can be held and positioned by a manipulator, such as for example a gripper device to a computer controlled robotic device, for assembly with another component of the pattern assembly. The datum embossments are located on a portion of the pattern that will be removed from the final metallic casting made to replicate the pattern. The casting includes integral cast datum embossments thereon by which the casting can be held and positioned.

Abstract: A method for making personalized jewelry and the personalized product of this jewelry making method. The method includes digitally capturing the image of a person or other object. The image is saved as a digital profile and processed to create a numerical profile. The numerical profile includes prototyping machine instructions that cause a prototyping machine to produce a wax block that contains a replica of the scanned object. The wax block is placed in a warm bath so that an outer wax melts away and an inner wax of the scanned object remains. The wax replica is then used in a “lost wax process” to make a mold of the wax replica. The mold is then used in a casting process wherein the mold is injected with precious, semi-precious, or base metals to make a cast of the object. The finished product is a replica of the object with exacting features such as nose, eyes, ears, etc. Any cavity or flat surface can be colored with epoxies, resins, enamels, or decorated further to give color contrast.

Abstract: There is provided a method or process for fabricating a hollow jewelry article which is hollowed or bored out to an arcuate estent of 200° or greater. In accordance with this process, a metal ring model is prepared comprising a solid shank and a metal plate supported along the internal perimeter of the shank and arcuately extending at least 200° therealong. A first metal mold is produced from the metal ring model having the external shape of the jewelry article to be manufactured. From this mold, a wax model of the jewelry article is produced which is first filed down and then cast in order to form a metal model of a core insert; the core insert, like the ring model, has a plate disposed along the perimeter of the shank. This core insert is used to produce a second metal mold. This second mold may then be used repeatedly in order to form a soluble wax core insert model which is then inserted into the cavity of the first mold in order to define the hollow region of the article.

Abstract: A casting includes a heat transfer surface having a plurality of cavities. The plurality of cavities include a density of at least about 25 cavities per square centimeter to about 1,100 cavities per square centimeter resulting in increased surface area and therefore enhanced heat transfer capability. Also disclosed is a mold for forming a pattern for molding the casting. The mold includes a surface defining a portion of a chamber to which are attached a plurality of particles having an average particle size in a range of about 300 microns to about 2,000 microns.

Abstract: An investment molding flask assembly having a base with a central positioning boss protruded from a center thereof and at least one positioning annular groove defined therein around the central positioning boss, and a conical sleeve formed with a small opening end to be securely positioned on the base without any displacement in horizontal directions by means of the central positioning boss or the positioning annular groove. Whereby, the conical sleeve can be readily removable from a solidified semi-finished investment mold, and then the solidified semi-finished investment mold is sent into an oven independently for heating. Therefore the sleeve can be used repeatedly, and the investment mold can be manufactured rapidly and readily.

Abstract: An investment casting or molding method comprises encasing a consumable pattern in a no-bake material that hardens without the application of heat. The encased pattern is then transformed to a fluid state and evacuated, thereby forming a mold cavity. Preferably, the pattern is coated with a refractory material prior to encasement, so that the resulting mold cavity is lined with the refractory material. Coating the pattern with one and only one layer of refractory material is preferred, resulting in a refractory coating that is not self-supporting. In another embodiment, a refractory-coated consumable pattern is located in a container, and a granular backing material is packed in the container around the coated pattern. The pattern is then transformed to a fluid state and evacuated to form a refractory-lined mold cavity in the container. The refractory coating again preferably comprises one and only one layer of refractory material, thereby resulting in a coating that is not self-supporting.

Abstract: A method of making a spray formed rapid tool includes the steps of making a model of a desired tool and constructing a ceramic pattern as the inverse of the model. The method also includes the steps of heating the ceramic pattern and thermally spraying a metal material against the ceramic pattern to form a desired tool.

Abstract: A fugitive pattern of an article to be investment cast wherein the pattern includes a plurality of locator embossments disposed in an array to provide a datum reference system by which the pattern can be held and positioned by a manipulator, such as for example a gripper device to a computer controlled robotic device, for assembly with another component of the pattern assembly. The datum embossments are located on a portion of the pattern that will be removed from the final metallic casting made to replicate the pattern. The casting includes integral cast datum embossments thereon by which the casting can be held and positioned.

Abstract: Method and apparatus for providing a plurality of locator elements on a ceramic core involves placing a ceramic core in a die cavity of die, positioning a plurality of pins in the die cavity with each pin having a locator-forming cavity on an inner end facing a surface of the core, and introducing melted wax into each locator-forming cavity to form a plurality of locator elements on the surface of the core.

Abstract: A mold for single crystal casting of molten metallic material is provided having a metallic seed crystal with a passage in an end thereof and an end of a fugitive connector member inserted in the passage. Another end of the connector member is connected to a fugitive pattern. The assembled seed crystal, member, and pattern are invested in a ceramic shell mold so that the mold is invested directly against a side of the seed crystal.

Abstract: A compressor wheel is re-designed to permit die inserts (20), which occupy the air passage and define the blades (4, 5) during a process of forming a wax pattern (21) of a compressor wheel, to be pulled without being impeded by the blades. This modified blade design enables the automated production of wax patterns (21) using simplified tooling. These wax patterns (21) can be used in a large-scale investment casting process, and produce an economical cast titanium compressor wheel which performs aerodynamically at high boost pressure/RPM. The compressor wheel improves low cycle fatigue, withstands high temperatures and temperature changes, and permits operation at high boost pressure ratio while, on the other hand, having low weight, low inertial drag, and high responsiveness.

Abstract: Method of making a shell mold for casting molten metals or alloys involves forming a thermally collapsible, low density reaction injection molded (RIM) thermosetting polyurethane foam pattern having a shape corresponding to the casting to be made. The pattern is formulated to have an aggregate density (pattern outer skin and pattern cellular core) in the range of about 10 to 15 lbs/ft3 and a smooth continuous as-molded surface devoid of surface connected open cells, dimensional stability over a range of temperatures, and ready, ashless burnout from the shell mold formed thereon without cracking the shell mold. The pattern is free of organometallic catalysts that should not be present in the casting of aerospace superalloys, such as nickel and cobalt base superalloys and titanium. The pattern then is invested without the need for any surface polymer or other film or layer in a shell mold.

Abstract: A process for producing dental devices such as teeth is disclosed. Specifically, a process for producing gold dental devices, such as gold denture teeth, is disclosed. The process includes the production of an injection mold based on an impression or mold of a target tooth. The injection mold can then be utilized to produce a hardened polymeric precursor of the product device. In particular, a hardened precursor can be produced from pure polypropylene. The precursor can be used as a model to produce an investment casting mold. The desired product material, for example a gold alloy, can then be cast in the investment casting mold by methods known in the art to produce the final product.

Abstract: The specification and drawings describe and show an embodiment of and method of forming a liquid flow through heat exchanger structure cast in a metal matrix composite. The composite comprises a preform reinforcement material infiltrated with molten metal. The composite reinforcement material is injection molded around the heat exchanger structure allowing for intimate contact between the composite and structure. The composite formed has a specific coefficient of thermal expansion to match active heat-generating device(s) mounted thereon. The present invention allows for enhanced thermal and mechanical properties by eliminating voids or gaps at the composite to heat exchanger structure interface, these voids or gaps being present in prior art fabrication methods or induced by usage due to thermal cycling of prior art composites.

Abstract: A machine for forming and fitting core support pins into wax (70) surrounding a core (68) prior to covering the wax (70) with a frit (76), includes one or more punch devices (30), (82) within its structure, so as to enable the forming of one or more indentations in each pin, intermediate its ends, thereby providing a designed weakness in the pin to cause it to more reliably follow slight relative movement which occurs between the pins and the part being cast, thus reducing stresses in the surface of the part.

Abstract: The invention relates to a method for producing a cast part of a thermal turbo-machine by way of a known casting process. Between a model mold and a ceramic insert, projections are located on the ceramic insert, whereby the projections have an angle (&agr;, &bgr;) between the center line and the outer edge of the projections of less than 30°, and whereby the projections are used both for the fixation of the insert during the casting process and for the reduction of the notch factor inside the recesses created in the cast part.

Abstract: The present invention relates to improvements in and relating to investment casting. In particular, the invention provides a method of investment casting, comprising the steps of mixing a binder, a refractory material, and a quantity of water-insoluble organic fibers to form a slurry; coating an expendable pattern with a coat of said slurry; and drying said coat or allowing said coat to dry to form a shell. The present invention further provides a refractory slurry for use in the method of the invention, and a kit of ingredients for putting the method of the invention into effect.

Abstract: The invention relates to a method for producing a cooled cast part for a thermal turbo machine by using a known casting process. Between a wax model of the cast part and a ceramic core, a wax seal is applied by hand above a step, only on an additional shoulder. The material that is created during the casting process at this point by the shoulder and the wax seal can be ground off without causing rough areas on the step to form. This simplifies the welding or soldering of a cooling plate to the step.

Abstract: A ceramic casting shell mold having a pre-selected shape is described. It includes alternate, repeating layers of a ceramic coating material and a ceramic stucco, defining a total thickness of the shell mold; and a ceramic-based mat of reinforcing material disposed in the alternate, repeating layers of coating material and stucco. The reinforcing material for the mat is usually made from a ceramic material, and includes fibers having a bi-directional orientation. A method for making a ceramic casting shell mold is also described, as well as articles cast from such a mold, e.g., superalloy articles.

Abstract: An investment cast stainless steel article, such as a marine propeller, is composed of a stainless steel alloy containing from 14.5 to 15.2% chromium, 5.35% to 6.05% nickel and 1.0% to 1.5% silicon.

Abstract: A ceramic investment shell mold is reinforced with a carbon based fibrous reinforcement having an extremely high tensile strength that increases as the mold temperature is increased especially within the range of casting temperatures employed for casting large directionally solidified industrial gas turbine components. The carbon based fibrous reinforcement is wrapped or otherwise positioned around the repeating ceramic slurry/stucco layers forming the intermediate thickness of the shell mold wall. The reinforced shell mold can be used to cast large directionally solidified industrial gas turbine components with accurate dimensional control.

Abstract: A thermally highly loaded casting is produced. The casting mold is produced from a slurry using a wax model and a polymer foam which is fixed to the wax model or has been introduced into a cavity. In this way, during the casting process the liquid superalloy also penetrates into the open-cell structure of the casting mold, so that an integral cooling structure is formed during the solidification of the casting. A single-crystal or directionally solidified casting is advantageously produced. It is also conceivable to vary the cell size of the polymer foam, to produce a cooling structure and a base material separately, and to coat the cooling structure with a ceramic protective layer (thermal barrier coating).

Abstract: A casting includes a heat transfer surface having a plurality of cavities. The plurality of cavities include a density of at least about 25 cavities per square centimeter to about 1,100 cavities per square centimeter resulting in increased surface area and therefore enhanced heat transfer capability. Also disclosed is a mold for forming a pattern for molding the casting. The mold includes a surface defining a portion of a chamber to which are attached a plurality of particles having an average particle size in a range of about 300 microns to about 2,000 microns.

Abstract: A process for producing a casting core which is used for forming within a casting a cavity intended for cooling purposes, through which a cooling medium can be conducted, the casting core having surface regions in which there is incorporated in a specifically selective manner a surface roughness which transfers itself during the casting operation to surface regions enclosing the cavity and leads to an increase in the heat transfer between the cooling medium and the casting.

Abstract: A ceramic investment shell mold is reinforced with a carbon based fibrous reinforcement having an extremely high tensile strength that increases as the mold temperature is increased especially within the range of casting temperatures employed for casting large directionally solidified industrial gas turbine components. The carbon based fibrous reinforcement is wrapped or otherwise positioned around the repeating ceramic slurry/stucco layers forming the intermediate thickness of the shell mold wall. The reinforced shell mold can be used to cast large directionally solidified industrial gas turbine components with accurate dimensional control.

Abstract: An article, such as an airfoil, is cast by a lost wax investment casting process. The process includes providing a core having a configuration corresponding to the configuration of a space to be formed in the airfoil. The core is at least partially enclosed with a layer of wax. A portion of the layer of wax is removed from the core. The step of removing a portion of the layer of wax from the core includes heating a tubular member and melting a portion of the wax layer by engaging the wax layer with the heated tubular member. Molten wax is conducted away from the core through the heated tubular member. A mold is formed by at least partially coating the wax layer with mold material which extends across the core at the locations where the melted wax was conducted away from the core. The wax layer is removed to form a mold cavity which is filled with molten metal to cast the airfoil.

Abstract: The invention relates to a method for producing a cooled cast part (1) for a thermal turbo machine by using a known casting process. Between a wax model (10) of the cast part (1) and a ceramic core (6), a wax seal (8) is applied by hand above a step (7), only on an additional shoulder (9). The material that is created during the casting process at this point by the shoulder (9) and the wax seal (8) can be ground off without causing rough areas on the step (7) to form. This simplifies the welding or soldering of a cooling plate to the step (7).

Abstract: A ceramic casting shell mold having a pre-selected shape is described. The shell mold comprises repeating layers of a ceramic material which define its wall thickness and shape. At least one of the layers of ceramic material contains refractory whiskers which provide structural reinforcement to the shell mold. The whiskers are usually incorporated into a layer of the ceramic material which is disposed at a position off-center of the wall-thickness of the mold. A method for making a ceramic casting shell mold is also described, as are metal- or metal alloy components cast in these shell molds.

Abstract: A microwave-based process for dental casting includes the use of microwave radiation to obtain burnout of a wax pattern from an investment mold. Phosphate-based, thermal investment materials have been found suitable for use in the process.

Abstract: To produce a thermally highly loaded casting (1, 14, 16, 17) of a thermal turbomachine which is produced using a known casting process, the casting mold is produced from a slurry using a wax model and a polymer foam which is fixed to the wax model or has been introduced into a cavity. In this way, during the casting process the liquid superalloy also penetrates into the open-cell structure of the casting mold, so that an integral cooling structure (7) is formed during the solidification of the casting (1, 14, 16, 17). A single-crystal or directionally solidified casting (1, 14, 16, 17) is advantageously produced. It is also conceivable to vary the cell size of the polymer foam, to produce cooling structure (7) and base material separately and to coat the cooling structure (7) with a ceramic protective layer (thermal barrier coating) (11).

Abstract: A disposable plunger for use in a pressing furnace for the fabrication of dental restorations. The plunger is fabricated of a refractory investment material such as gypsum-bonded, phosphate-bonded or ethyl silicate-bonded investment materials. The plunger is fabricated by known casting methods. The mold used for making the plunger can be supplied by a manufacturer of molds or can be easily made by using an alumina or similar plunger as a model. Laborious cleaning and grinding are not required with plungers herein described. Cracking problems that occur with prior art plungers are decreased, if not completely eliminated.

Abstract: A vent-forming apparatus for use in metal casting comprises a gas-permeable membrane with a lead-in tube attached to one surface and a breather tube attached to the opposite surface. The vent-forming apparatus may be used to create independent vents in the walls of shell-type molds used in the ceramic shell casting process for lost wax casting of ferrous and non-ferrous alloys. These vents exhaust gasses in the mold cavity to the atmosphere. The vent-forming apparatus also may be used in solid mold investment casting methods or in any other casting method in which venting is desirable or necessary.

Abstract: A ceramic investment shell mold is reinforced with a carbon based fibrous reinforcement having an extremely high tensile strength that increases as the mold temperature is increased especially within the range of casting temperatures employed for casting large directionally solidified industrial gas turbine components. The carbon based fibrous reinforcement is wrapped or otherwise positioned around the repeating ceramic slurry/stucco layers forming the intermediate thickness of the shell mold wall. The reinforced shell mold can be used to cast large directionally solidified industrial gas turbine components with accurate dimensional control.

Abstract: Disclosed is an integral single-cast multi wall structure including a very thin wall and a second thin wall. There is a passageway interposed between the pair of walls of the structure, and a high thermal conductivity member extends into said passageways and thermally couples the walls. The high thermal conductivity member increases the heat transfer between the walls of the structure. The present invention further includes a method for casting an integral structure having very thin walls that utilizes the high thermally conductive member in the casting process to hold the pattern and cores in alignment.

Abstract: A microwave-based process for dental casting includes the use of microwave radiation to obtain burnout of a wax pattern from an investment mold. Phosphate-based, thermal investment materials have been found suitable for use in the process.

Abstract: An item of jewelry such as a ring, earring, pin, pendant, tie tack, tie clip, tie bar, broach, bracelet, watch or wristwatch, hair pin, barrette, necklace, button, cuff links, or a medallion, and a method for forming the same wherein the item comprises the form of hair in an aesthetically pleasing geometric configuration such as a braid, said item having been cast in a mold formed at least in part by a sample of hair such as human or pet hair. Such an item which is made by investment casting, wherein at least a portion of the investment mold pattern comprises the hair sample. Such an item with a permanent designation of the person who was the source of the hair. Such an item used to adorn a memorial such as a crematory urn, picture frame, or memorial plaque.

Abstract: An implantable prosthesis having porous textured surface regions and methods for making the same provide improved prostheses and prosthesis manufacturing methods. The implantable prostheses contain one more bead preforms that are secured to the metallic prosthesis components during the casting process to form porous textured surface regions in desired areas of the prostheses.

Abstract: Fold defects are reduced or eliminated in lost foam castings by contacting a destructible polymeric pattern surface proximate to which deleterious fold defects comprising unbonded seams are prone to form in the solidifying molten metal with a material that reduces or eliminates fold defects in the casting proximate the pattern surface. The material can comprise a silicone layer that is anti-sticking relative to a gas permeable refractory layer on the pattern or foundry sand directly contacting the pattern surface depending on casting configuration. The pattern is cleaned prior to contact with the material. Lower melt casting temperatures can be used with concomitant improvements in casting microstructure (e.g. finer dendritic arm spacing) and mechanical properties.

Abstract: A rigid bar (or segment) on which stones will be at least partially supported is positioned in a rubber mold for creating a wax pattern of the jewelry, injecting wax to form a wax model of the jewelry including the metal bar to fit into an incision in the stones. The model with the metal bar forms the invisible pre-set stone mount. Stones are then placed into set position in the wax pattern on opposite sides of the metal bar. Once the setting is complete, the jewelry is created using known “lost-wax” method of manufacturing jewelry.