Insulated mold cavity assembly and method for golf ball manufacturing

Abstract

An insulated injection molding cavity assembly for molding a thin or low flow material golf ball cover or mantle layer, comprises a cavity for defining a golf ball layer, the golf ball layer comprising a thickness that corresponds to a space defined by the cavity; a metal surface layer surrounding the cavity, and an insulating layer surrounding the metal surface layer. The metal surface layer thickness is decreased and the insulating layer thickness is increased with decreasing golf ball layer thickness.

What is claimed is: 
     
         1 . An injection mold cavity assembly, comprising:
 first and second opposing mold halves each having a half cavity shaped to define half of a mold cavity facing the opposing mold half to form a complete cavity configured to receive and surround a suspended golf ball core in the cavity, whereby a mold cavity is defined between the golf ball core and the mold halves;   each mold half comprising a metal base having a first face with a base cavity, a metal shell having a mating cavity portion engaging in the hemispherical base cavity, the hemispherical portion having an inner surface configured to form half of the spherical cavity and an outer surface, the inner surfaces of the metal shells of the opposing mold halves being configured to form the outer surface of a golf ball cover or mantle layer, and an insulating layer between at least part of the outer surface of the metal shell and first face of the base.   
     
     
         2 . The assembly of  claim 1 , wherein the insulating layer secures the metal shell to the metal base. 
     
     
         3 . The assembly of  claim 1 , wherein the metal shells are configured to form a golf ball cover layer and the inner surface of each metal shell has a predetermined surface shape configured to form a selected surface configuration on the outer surface of a golf ball. 
     
     
         4 . The assembly of  claim 3 , wherein at least a major portion of the outer surface of each metal shell has a surface shape which is the inverse of the inner surface shape, whereby the metal shell is of substantially uniform thickness over at least a major part of the cavity portion of the shell. 
     
     
         5 . The assembly of  claim 3 , wherein the inner surface of each metal shell is configured to form a golf ball cover layer shape selected from the group consisting of: a plurality of identically shaped dimples, a plurality of dimples including dimples of different shapes, a plurality of dimples including dimples of different shapes and sizes, a plurality of dimples and protrusions, and tubular lattice shapes. 
     
     
         6 . The assembly of  claim 1 , wherein the metal shells are configured to form a golf ball mantle layer and the inner surface of each metal shell is at least substantially smooth to form a smooth outer surface of the mantle layer. plurality of protrusions configured for forming a selected dimple pattern in the outer surface of a golf ball cover or mantle layer, and the outer surface has a plurality of indents matching the protrusions, wherein the metal shell is of substantially uniform thickness over at least a major part of the hemispherical portion of the shell. 
     
     
         7 . The assembly of  claim 1 , wherein the base has a plurality of bores extending through the base into the hemispherical base cavity, and the outer surface of the shell has a plurality of protrusions for mating engagement in the bores, the protrusions extending along at least part of the length of the respective bores from the cavity. 
     
     
         8 . The assembly of  claim 1 , wherein the base has a peripheral rim surrounding the hemispherical base cavity, and the shell has a matching rim surrounding the hemispherical portion and engaging over the peripheral rim of the base, the peripheral rim of each shell half having a plurality of grooves forming injection molding ports with the grooves in the opposing shell half. 
     
     
         9 . The assembly of  claim 8 , wherein the insulating layer extends between the peripheral rims of the base and shell in each mold half at least in the region of the injection molding ports. 
     
     
         10 . The assembly of  claim 1 , wherein each mold half has at least four vent holes. 
     
     
         11 . A method of making a mold assembly configured to form half of an injection mold cavity assembly for forming a golf ball cover or mantle layer, comprising:
 forming a metal mold base of predetermined shape and dimensions;   cutting out an indented cavity in a first face of the mold base;   drilling holes through the base to extend into the cavity;   forming a metal half shell having an indented cavity portion dimensioned to fit into the indented cavity in the metal base and a rim surrounding the cavity portion, the half shell having opposite outer and inner faces;   inserting the cavity portion of the metal half shell into the cavity of the base with the outer face facing the cavity and spaced a predetermined distance from the cavity;   securing the half shell to the base with an adhesive insulating material having insulating properties, whereby the adhesive insulating material forms an insulating layer filling the space between the half shell and cavity across at least part of the outer face of the shell; and   allowing the adhesive insulating material to cure.   
     
     
         12 . The method of  claim 11 , wherein the cavity comprises an at least substantially hemispherical cavity and the shell cavity portion comprises an at least substantially hemispherical portion configured to engage in the cavity. 
     
     
         13 . The method of  claim 12 , further comprising forming a predetermined surface pattern on the outer surface of the hemispherical portion of the metal half shell prior to insertion of the hemispherical portion into the cavity, and forming a matching inverse pattern on the inner surface of the hemispherical portion of the half shell before or after insertion of the hemispherical portion into the cavity. 
     
     
         14 . The method of  claim 13 , wherein the inverse pattern is cut into the inner surface of the hemispherical portion after the adhesive insulating material has cured and secured the half shell to the first surface of the base. 
     
     
         15 . The method of  claim 13 , wherein the outer surface pattern comprises dimples and the inner surface pattern comprises matching inverse dimples. 
     
     
         16 . The method of  claim 13 , further comprising forming a plurality of projections on the outer surface of the metal half shell for engaging the holes in the mold base. 
     
     
         17 . The method of  claim 11 , wherein the inner surface of the metal half shell is a curved surface having no projections or indentations and is configured to mold half of an inner layer of a golf ball. 
     
     
         18 . The method of  claim 11 , further comprising coating a layer of adhesive insulating material onto the first face of the base prior to inserting the cavity portion of the half shell into the cavity in the base.