Abstract: A process for producing a hollow metal cast product having a desired interior contour is provided. The process comprises the steps of preparing a first lost model having an outer contour substantially corresponding to a desired interior contour of the finished product, depositing a metallic or ceramic material or a mixture thereof over the surface of said first lost model by spraying to form a layer defining a hollow core block, placing said hollow core block in a first mold, pouring or injecting a material for forming a second lost mold into said first mold to form a second lost model, coating a refractory material over said second lost model to form a second mold for casting, removing second lost mold to form a cavity, casting a molten metal or alloy into said cavity, and staving said second mold to take out a finished product.

Abstract: An injection nozzle assembly is used for molding a plurality of articles having accurate dimensions without causing a sink mark to appear in the molded article. The injection nozzle assembly comprises a body which is heated to a temperature higher than the melting point of thermoplastic material. A cylindrical bore is formed within the body, and an outlet port is formed at one end of said cylindrical bore. A plunger moves within the cylindrical bore between a first position near the outlet port to a second position which is remote from the outlet port. A first feed line supplies the molten thermoplastic material and a second feed line feeds high pressure through passageways that are formed within the body. The plunger is formed within a first passageway connecting the feed line with the outlet port when the plunger is moved to the second position. The pressure at the outlet port is reduced by the movement of the plunger from the first position to the second position.

Abstract: A casting apparatus having a casting chamber which may be sealingly closed is provided. The casting chamber is evacuated and then an inert gas or a reducing gas is introduced prior to the casting operation. A ladle for containing a one-shot molten metal is disposed on the casting chamber to be evacuated simultaneously with the evacuation of the casting chamber and then surrounded by an inert or reducing gas atmosphere during the casting operation.

Abstract: An improved wax master tree used for precision casting is provided. The tree comprises a sprue rod and a plurality of wax masters attached to the sprue rod by fusing. In the improved wax master tree of the invention, the sprue rod is made of a substantially rigid material having a sufficient mechanical strength and withstanding to retain its integrity during the dewaxing step, and has a contour of generally tubular shape with the wall provided with a number of pores and covered with a wax covering layer. The rigidity of the tubular member ensures easy handling of the tree without the fear of damage during the handling operations. By the provision of hollow core portion internally of the tubular member having a wall provided with a number of pores, the risk of cracking of the ceramic shell mold applied on the wax master tree at the dewaxing step caused by the adverse affect of thermal expansion of the wax can be avoided.

Abstract: A system for sintering molds and for preparing cast products by the use of the thus preformed molds is provided. The system is particularly suited for the production of cast articles made of an alloy, such as magnesium alloys, which is susceptible to cracking unless the cast mass is slowly cooled at least across the solid solution forming temperature range. The system comprises a composite sintering-annealing furnace including a sintering furnace section and an annealing furnace section. The sintering and annealing furnace sections are juxtaposed to be adjacent with each other and separated by a partition wall through which a plurality of ventilation windows is formed for communicating both sections with each other. A plurality of atmospheric air inlet ports is provided through an external wall defining the annealing furnace section.

Abstract: An injection molding process for molding an article having accurate dimensions without sink marks includes the step of feeding high pressure air into the core portion of a shell or solid molded mass formed by the preceding injection molding step. Preferably, the wax material is injected into a mold cavity through a throttled inlet port to flow thereinto as a vigorous turbulent flow. A separate flow line is provided for feeding high pressure air in the preferred embodiment. More preferably, the volume of injected wax is substantially smaller than the volume of mold cavity.

Abstract: A combination sintering-annealing furnace is provided, wherein the sintering furnace section and the annealing furnace section are arranged adjacent with each other and separated by a partition wall. A plurality of ventilation windows is provided through the partition wall to allow the waste combustion gas in the sintering furnace to flow into the annealing furnace. The opening area of each ventilation window is adjusted by an adjuster plate. The annealing furnace is also provided with a plurality of cold air inlet ports for introducing therethrough cold air from the atmosphere, the opening area of each cold air inlet port being adjusted by an adjuster plate. A desired temperature distribution in the annealing furnace may be established by controlling the opening areas of the respective ventilation windows and respective cold air inlet ports.

Abstract: A process for dewaxing a mold for use in lost wax casting is proposed, wherein the mold is loaded on a pallet which is placed and then securely held on a carrier which is rotatably assembled in a dewaxing tank. The mold is inverted to be ready for dewaxing within the tank and then returned to the initial condition within the tank by rotating the carrier by about 180 degrees at a time.An autoclave for use in the process comprises a carrier framework rotatably disposed within a dewaxing tank for carrying a pallet loaded with shell mold trees. The carrier framework is held in a first position for assembling the pallet and then is rotated by about 180 degrees to a second inverted position to hold the pallet securely in the inverted condition during the dewaxing operation.A preferred embodiment of the autoclave further comprises means for securely fastening the pallet and the mold trees automatically and simultaneously with the operation of sealingly closing the entrance opening of the dewaxing tank.

Abstract: An improved system for the preparation of ceramic shell molds comprises a rotary disk which is mounted for rotating in a substantially horizontal plane. A plurality of wax master mounting bars are pivotally carried by the rotary disk to move around the periphery of the rotary disk. The mounting bars have free ends loaded with the wax masters. The rotary disk is operatively associated with the wax master mounting bars for swinging and rotating the bars on their own axes as the rotary disk rotates continuously. The preferred embodiment comprises a cam of generally twisted undulating cam strips and a roller attached to the base ends of the bars for frictionally engaging the cam face of the cam strip to swing the bars and to rotate them on their own axes. A slurry bath, a drain bath, and a stucco bath are arranged around the exerior side of the periphery of the rotary disk.