Abstract: A method of making a spray formed article includes the steps of providing a sand pattern and spraying metal material toward the sand pattern to form the desired article. The sand pattern is made from a sand molding composition comprising refractory materials and binder. The refractory material comprises at least about 15 weight percent alumina, based on the total weight of the refractory material.

Abstract: There is provided a method for producing a dental prosthesis comprising: obtaining three-dimensional digital data relating to a patient's dentition; designing a virtual prosthesis for the dentition using the three-dimensional digital data; transmitting digital data corresponding to the virtual prosthesis to an automated prototyping system; producing a prototype of the dental prosthesis with the automated prototyping system, the prototype made of a material that can be ablated; covering at least the prototype with a hardening material and removing the prototype from within said hardening material to produce a mold for the dental prosthesis; casting the dental prosthesis by filling the mold with a metal and removing the hardening material.

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 sand casting facing composition comprises a dry mixture of about 77% fine sand, 5% binder, 6% green system sand and 12% burned system sand. The fine sand is mulled with 5.8% wt/wt oil per total dry mixture and catalyst at about 0.5% wt/wt. Preferably, fine sand and binder are mulled with oil, catalyst, green system sand and screened burned system. The mulled mixture is rested, mulled again and rested again before use as facing sand for achieving accurate reproduction of the pattern's fine detail. A method of preparing the mold and preserving fine detail comprises riddling the pattern with a thin layer of the facing sand composition, compacting, riddling with dry system sand and riddling with system sand before compacting about the periphery of the pattern. Final layers of system sand are applied and compacted over the entire pattern.

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: A mold apparatus and method for creating designs on the interior of molds includes a resilient form with an exterior and an interior, with a design formed on the exterior. A rigid support member is removably attached to the interior of the resilient form. A mold pattern, conformed to removably receive the rigid support member and the resilient form in combination, completes the basic elements of the invention. In one aspect of the invention, a passageway in the rigid support member is provided for introducing a gas between the rigid support member and the resilient form. In another aspect of the invention, a vacuum application device is provided for applying a vacuum to the interior of the resilient form.

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 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: Cost considerations have prevented the use of titanium compressor wheels (1) in automotive air boost devices. A hybrid process is disclosed, wherein a wax pattern used in the investment casting process is intentionally designed not to produce a final (net shape) compressor wheel, but rather, is designed to produce a near net shape pattern including filled in areas (10, 11) which must be subsequently machined or milled away to produce the desired non-pullable shape compressor wheel. Surprisingly, when forming a titanium compressor wheel using the hybrid or two-step process, the technical complexity of each step (pattern forming and machining) is substantially lower, distortion of the wax blades (4) during pattern casting is reduced, casting of titanium is simplified, the process allows itself to be fully automated, and the dimensional accuracy of the final product is greater than with conventional techniques.

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 process for the assembly of wax trees in which a wax runner is placed in a flat position and a wax pattern is located adjacent the wax runner. Both the wax runner pattern and the wax runner are heated and then are placed in contact with one another where heated. Then the wax pattern and the wax runner are separated slightly to form a fillet weld between the wax pattern and the wax runner. An apparatus is also provided which, by robotics, brings a multiplicity of wax patterns to a wax runner and which automatically heats both the wax patterns and the wax runner before simultaneously pressing both the wax pattern and the wax runner together. Once a wax tree assembly is completed a new wax runner replaces the wax runner that has been formed into a wax tree and additional wax runners are affixed in the same manner.

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: The invention is directed to a method for directly producing a lost mold by machining a sand mold made with curable binders. The invention is intended in particular to decrease tool wear and to increase dimensional accuracy and exactness in the reproduction of the mold, in that a mold blank (1) to be machined is constructed by means of a pattern set (4) with the use of a variable or fixed molding box (2) and includes in its volume the desired contours of the casting mold and a machining allowance for the milling of the mold material. After filling of the molding box (2) with curable foundry mold materials, curing, and removal from the mold, the mold blank (1) is transformed into the casting mold by removal of the machining allowance by high-speed machining, milling or 3-D machining of freeform surfaces. The invention concerns lost molds for metal castings and the fabrication of casting prototypes and odd parts in the range of small-and medium-sized articles and production runs.

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 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 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 method of forming a turbine engine component, includes providing a mold having a textured region, pouring a molten alloy into the mold, and cooling the molten alloy to form a turbine engine component, wherein the turbine engine component has an enhanced surface area region corresponding to the textured region of the mold, the enhanced surface area region comprising randomly arranged bumps.

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 casting includes a heat tranfer surface having a pluality of cavities. The plurality of cavities includes 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 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: 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 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 method of molding a jewelry ring having a beveled or rounded inner diameter and a hollow portion in a vertical mold comprises utilizing a multi-piece plug and a soluble insert in a mold to define a mold cavity in the desired shape of the ring or a portion of the ring. A molten material is introduced into the mold cavity and upon hardening forms a ring replica which is removed from the mold by first removing the formed ring replica from the mold halves and then removing the ring replica from the multi-piece plug by separating the multi-piece plug into its individual pieces. The ring replica can be used to form jewelry rings by investment casting.

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 tool (40) has a ledge portion (46) and a cutting blade portion (50) for cutting a groove (24, 26, 28) in a wax model (32) for an article of jewelry. The groove is formed after the wax model is formed by mechanical removal of the wax, preferably by cutting with tool (40). The wax model and gems are then placed in an investment mold where the lost wax technique is used to form an article of jewelry with the gems set therein.

Abstract: A method of forming a gold statuette of a three-dimensional object, e.g. a man, is disclosed as including the steps of (1) scanning the man with scanning means to obtain data on his contour and shape; (2) inputting the data into a computer; (3) based on the data inputted into the computer, displaying a virtual three-dimensional image of the man on a monitor of the computer; (4) providing an epoxy resin prototype of the man by a sculpturing machine controlled by the computer; (5) providing silicon rubber mould-halves on the basis of the epoxy resin prototype; (6) providing a wax prototype on the basis of the silicon rubber mould-halves; (7) casting gold onto the wax prototype; (8) removing the wax, in which the scanning means revolves around the man to scan his contour and shape.

Abstract: Method of rapidly making casting, comprising: designing a computer graphic model of the casting; sectioning the graphic model into graphic members which are at least one of blocks and slabs; carving a solid member for each of the graphic members, the solid members being (i) constituted of a meltable or evaporative solid material (i.e. wax or polystyrene), (ii) proportional to and enveloping its corresponding graphic member, and the carving being carried out by accessing two or more sides of each solid member to at least essentially duplicate the corresponding graphic member; forming a mold around the pattern, and casting metal within the mold while removing the pattern from such mold either by evaporation during pouring of the molten metal thereinto or by melting prior thereto.

Abstract: A fingerprint jewelry includes any jewelry with a person's fingerprints cast in relief onto its surface. It is made by pressing a finger on a sheet of pliable wax medium to imprint it with fingerprints in relief. In a first embodiment, the wax medium is comprised of a soft wax medium soft enough to be imprinted at room temperature. In a second embodiment, the wax medium is comprised of a soft wax medium supported on a hard wax medium. The imprinted wax medium is positioned in a hollow form. A mold is created around the wax medium by pouring a mold material into the hollow form. An oven is used to harden the mold material and melt away the wax to leave a mold cavity. Molten precious metal is cast into the mold cavity with a casting machine to produce a casting with the fingerprints in relief. The casting is freed by breaking the mold. Additional work may be performed on the casting to produce a finished piece of jewelry.

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 method of producing reticular structures, particularly metallic reticular structures, as well as a device suitable for the production thereof. The method and device enable continuous and/or automated production of such structures, and particularly, large-scale automated production of large-dimensioned reticular structures. A reticulated foam pre-structure is placed into a first container and infiltrated with a refractory material. After solidification, the mold formed by the refractory material is removed from the first container and the foam pre-structure stripped from the mold. The mold is then pre-heated and placed into a second container and infiltrated with a molten substance that forms the reticular structure when solidified. The filled mold may be covered with a solid jacket as a means of controlling the rate and progression of solidification of the molten substance to form a fine-grained, bubble-free structure.

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 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: The lost foam method of casting a cylinder liner with water jacket comprises the steps of creating a blank identical to the liner desired, with a drain defined therein, from a heat-dissipated material such as styrofoam, coating the blank with core wash, placing the blank into a casting mold, filling the mold and a chamber defined within the blank with sand, pouring hot metal into the mold, extracting the formed metal liner from the mold, draining sand from within the chamber and plugging the sand drain.

Abstract: The present invention relates to a method of making a molding tool comprising a core die and a cavity die. The method comprises (a) providing a first metal deposit comprising one of the cavity die or the core die, the first metal deposit having a die face, (b) providing a spray forming pattern on a portion of the die face of the first metal deposit,(c) spraying metal particles onto the first metal deposit and the spray forming pattern to form a second metal deposit comprising the other of the cavity die or the core die, and (d) removing the spray forming pattern from the first and second metal deposits.

Abstract: A stereolithography machine is employed to solidify a pattern including a series of stacked grids forming the pattern having an outer skin and inner labyrinth and any number of gates. The hollow pattern is mounted on a central sprue through runners at the gate of the pattern. The pattern is dipped in ceramic slurry and sifted in a refractor grain in order to coat the hollow pattern. The hollow pattern is melted to form a mold.

Abstract: This invention involves a method of promoting solubility of a polymeric material of a master for separating the master from a mold in contact therewith to form a desired geometry on the mold. The method comprises providing a mixture of a non-polymeric organic material and polymeric material, and providing a molten material and a supercritical fluid. The non-polymeric organic material represents about 25% to 75% of the weight of the master. The polymeric material represents the balance of the weight of the master. The method further includes forming a master from the mixture. It has a predetermined shape on a contact surface thereof. The method further includes forming a mold in contact with the contact surface of the master, wherein the master and mold have relative mating surfaces to form the desired geometry on the mold. The method further includes separating the master from the mold by exposing the master to the supercritical fluid.

Abstract: The evaporative casting of molten metals has been shown to produce castings having smooth surfaces with significantly less signs of carbon deposits thereon by using an expandable vinyl aromatic polymer containing a bromine-attached aliphatic or aromatic flame retardant.

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. A mold for forming a pattern for molding the casting 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 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 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: The method of lost foam casting uses a polystirene foam pattern molded from polystirene beads preexpanded from raw polystirene beads that have a raw bead diameter in the range of about 0.1 to about 0.6 millimeters and that include isopentane as a relatively slow diffusing blowing agent alone, or together with normal pentane as a relatively high diffusing blowing agent, the isopentane being present in an amount of at least about 40% by weight of the total blowing agent of the raw beads to significantly reduce post-molding dimensional pattern shrinkage and to render the molded patterns inherently more dimensionally stable. The patterns can be used directly in the lost foam casting of molten metal without the need for any intermediate pattern dimension-stabilizing treatment.

Abstract: The invention relates to a process for preparing free flowing particles covered with a layer of water glass, comprising the steps of: (a) providing a mixture containing particles to be covered, water and 0.1-5% by weight water glass, calculated on the basis of the weight of the particles, the water glass being dissolved in said mixture, and (b) stirring the mixture mechanically, optionally by supplying heat from an external heat source, and permitting the water to evaporate from the mixture until at least so much water is evaporated that said mixture is no longer sticky. Furthermore, the invention relates to a process for preparing an article with a detailed surface.

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 method for producing a mold for making an integrally formed three-dimensional truss structure, containing outer top and bottom plane surfaces thereof comprising interconnected rod segments integrally formed at their points of intersection on the outer top and bottom surfaces, the top and bottom surfaces also integrally joined together through additional interconnected rod segments passing through an integrally formed intersection, wherein the additional interconnected rod segments passing through the integrally formed intersection form a three-dimensional continuous array of triangles.

Abstract: The method comprises the production of a first positive model of an item to be cast. The positive model is produced with a flange extending in an imaginary separation line of the item. The flange extends both inwardly in the item within an outer periphery of the item and outwardly outside the outer periphery of the item. The flange establishes an artificial increase of the thickness of the item. Through different intermediate steps at least a first mould part and a second mould part of a mould are produced. The first and the second mould part of the mould initially have a separation zone forming a contact surface between the first and the second mould part. The mould parts are treated in the separation zone so that the negative moulds of an upper and a lower surface of the part of the flange extending outside the item will subsequently form a contact surface of the first and the second mould part.

Abstract: A process for fabricating a hollow or partially hollow article, such as a jewelry ring, comprises producing a first mold having an inner cavity shaped in accordance with the external shape of the article to be produced. A second mold is produced for forming a wax core insert which is inserted in the first mold cavity for forming the hollow region of the article. The second mold has an inner cavity formed in the shape of, but slightly smaller than, the external shape of the article. The cavity of the second mold has holes which form spacer pins on the wax core insert. The wax core insert is then placed in the cavity of the first mold and is maintained in a precise, predetermined position by the spacer pins. During waxing of the article, a plastiwax is introduced into and fills the cavity of the first mold, completely surrounding the wax core insert. The plastiwax hardens and is removed from the first mold cavity with the wax core insert.