Hollow articles and method of manufacture

Abstract

A hollow jewelry pendant or bead formed by investment casting is disclosed. The method of manufacture consists of producing a mold usually consisting of metal, silicone or rubber containing a cavity for injecting an inner soluble core. A geometric lock is also formed as part of the injection core which will orientate the core both laterally and radially. This core will define the inner surface or hollow portion of the pendant as well as form the bail or hole through which the chain will slide. A second mold is produced usually consisting of metal, silicone or rubber containing a cavity into which the soluble core will be placed with the lock positioning the core so as to insure proper orientation. This is critical for consistent wall thickness and matching of design features. The cavity also allows for a wax or plastic material suitable for investment casting to be injected around the soluble core. The part consisting of the pendent or bead and soluble core is then removed from the mold and the core is dissolved using the appropriate water or chemical solution.

1 . A method of manufacturing a hollow article formed by investment casting comprising the steps of:
 providing a first mold comprising a first half and a second half;   forming a soluble core that will define the interior of the article; the soluble core comprising a geometric lock to accurately position the soluble core both laterally and radially   positioning the soluble core in a second mold defining the exterior of the article; and   Injecting a molten wax, plastic or suitable material around soluble core.   
   
   
       2 . An article manufactured according to the method of  claim 1 . 
   
   
       3 . The article of  claim 2 , wherein the article comprises a pendant or bead. 
   
   
       4 . The article of  claim 2 , wherein ports used to inject and remove the soluble core also form functional features of the article. 
   
   
       5 . The article of  claim 2 , wherein the article has a material volume to surface ratio less than 1 to 1.