초록 ▼

An improved method and apparatus for high-pressure injection or compression molding of optical thermoplastic parts such as lenses or optical disks, wherein the optical surfaces of a molded part are formed by intimate contact with suitably contoured or profiled and lapped surfaces of one or more opti

An improved method and apparatus for high-pressure injection or compression molding of optical thermoplastic parts such as lenses or optical disks, wherein the optical surfaces of a molded part are formed by intimate contact with suitably contoured or profiled and lapped surfaces of one or more optical mold insert elements. The optical surface of such mold element is of a different composition metallurgically than is the bulk composition of the rest of the mold element, thus allowing for optimum selection for materials-of-construction parameters (such as heat transfer, load-bearing quality, and ease of fabrication) in the bulk properties of the substrate metal, without necessarily trading off against optimum optical surface characteristics (such as imperviousness to chemical oxidation or attack, resistance to scratching and abrasion, ease of generating optical surface therein). Thus, a one-piece construction (not mechanically joined from separate elements) of a seamless nature, generally consists of at least one layer of relatively thick electroplating (nickel or chromium) onto a beryllium-copper alloy substrate of certain specified mechanical and thermal characteristics. Heat transfer is further improved by means of machined flow channels provided for circulating liquid coolants. A most preferred mold element construction consists of, first, a machined beryllium-copper substrate onto which a thick watts nickel plating was deposited, followed by abrasive lapping to create the specified surface contour to a high level of microstructure perfection and smoothness, onto which a final thin hardcasting of either vacuum-deposited TiN or flash plate of chromium is deposited.

대표청구항 ▼

A special mold cavity member for use in high-pressure injection and compression molds for forming optical thermoplastic parts wherein the parts are formed by intimate contact under high pressure within the mold cavity comprising: (a) at least one optically-lapped surface composed of an electroplated

A special mold cavity member for use in high-pressure injection and compression molds for forming optical thermoplastic parts wherein the parts are formed by intimate contact under high pressure within the mold cavity comprising: (a) at least one optically-lapped surface composed of an electroplated nickel, said lapped surface facing into said mold cavity so as to permit incoming molten thermoplastic to wet said surface during filling of the cavity so as to form the part during pressurization of the molten thermoplastic in the mold cavity, and thus to replicate the lapped surface in the resulting thermoplastic optical parts; and (b) a suitably dimensioned, load-bearing substrate component of the mold cavity member, wherein the substrate component is of a beryllium-copper alloy composition, and the resulting mold cavity member is of a seamless, monolithic construction, consisting of a beryllium-copper substrate integrally joined with a nickel plated face. A method of forming a special mold cavity surface for use in high-pressure injection and compression molds for optical thermoplastic parts wherein the optical surfaces of said thermoplastic parts are formed by intimate contact under high pressure with certain elelments of the mold cavity, comprising the steps of: (a) depositing a nickel surface through electroplating or electroless deposition onto a suitably dimensioned, load-bearing substrate component of the mold element, the substrate being of a beryllium-copper alloy, and (b) lapping optically said deposited nickel surface composed of an electroplated or electroless nickel, the lapped surface facing into the mold cavity so as to permit the incoming molten thermoplastic to wet the surface during filling so as to form the part during pressurization of the molten thermoplastic in the mold cavity, and thus to replicate the lapped surface in the resulting thermoplastic optical part, and the resulting mold element being of a seamless, monolithic construction, including a beryllium-copper substrate integrally joined with a nickel plated face.