Abstract: Various techniques are provided for creating fugitive foam patterns for use in investment casting operations. In certain illustrative embodiments, a fugitive foam pattern is assembled from independently formed portions. A first section is formed in a mold. Once cured, a mating surface of the first section is exposed to the cavity of a second mold and the section is formed. The second section integrally adheres to the first section. The process is repeated as necessary. In alternative embodiments, a channel is created in a foam pattern using a temporary core that is removed without chemical leaching. The core material comprises water-soluble materials, acid-soluble materials, low-melting point materials, or a combination thereof. A pattern may also be created by inserting foam around a core that remains with the foam pattern.

Abstract: A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

Abstract: A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

Abstract: A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

Abstract: A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

Abstract: There is shown an injection molding apparatus, which comprises a source of a fluid molding material and a molding die into which the molding material is forced under pressure. The apparatus includes a control means for initiating and controlling an injection cycle in which the fluid molding material is injected into the molding die in a particular and predetermined manner. The control means generally comprises a programmable logic controller (PLC) which is programmed to receive signals from sensors adapted to sense variable parameters of the injection cycle. The PLC is programmed to generate control signals based upon the signals from the sensors so as to control the variable parameters of the injection cycle. The output control signals of the PLC are coupled through an interface circuit to a servo-control circuit which in turn is operatively coupled to control various parameters of the injection cycle.