System and method for molding soft fluid-filled implant shells

Abstract

Systems and methods for molding shells for fluid-filled prosthetic implants, including spinning and rotating dip- or spray-mandrels during a devolatilization step to ensure an even covering. The mandrels may be spun during the dipping or spraying step, and/or afterward while a solvent evaporates until a gum state is formed. The techniques are particularly useful for forming hollow shells from silicone dispersions for soft implants, such as breast implants.

What is claimed is: 
     
         1 . A method for molding a hollow shell useful as a surgical implant, the method comprising the steps of:
 providing an assembly comprising a mandrel and rod, the rod defining a first axis of the assembly;   spinning the mandrel about the first axis;   rotating the mandrel about a second axis different from the first axis;   applying a silicone dispersion to the mandrel by passing the mandrel through a silicone dispersion flow during the spinning to form a silicone dispersion coat on the mandrel; and   causing the coat to devolatize.   
     
     
         2 . The method of  claim 1  wherein the spinning is performed at a speed of about 5-15 rpm. 
     
     
         3 . The method of  claim 1  wherein the rotating comprises moving the mandrel between an upright and an inverted position. 
     
     
         4 . The method of  claim 1  wherein the step of causing the coat to devolatize is performed during the rotating. 
     
     
         5 . The method of  claim 1  wherein the step of causing the coat to devolatize is performed during the spinning. 
     
     
         6 . The method of  claim 1  wherein the step of causing the coat to devolatize is performed during the spinning and the rotating. 
     
     
         7 . The method of  claim 1  wherein the silicone dispersion flow is a silicone dispersion curtain. 
     
     
         8 . A system for manufacturing shells useful as surgical implants, the system comprising:
 a plurality of mandrel/rod assemblies, each including a rod and a mandrel;   a rotating assembly capable of rotating the mandrel/rod assemblies about a plurality of different axes including spinning each mandrel about a respective first axis;   a spray assembly capable of providing a dispersion spray;   a devolatization chamber; and   a drive assembly capable of moving the each of the mandrel/rod assemblies into the dispersion spray to form a dispersion coat on each mandrel, and capable of moving each of the mandrel/rod assemblies into the devolatization chamber such that each mandrel passes into the devolatization chamber while being rotated about the plurality of different axes.   
     
     
         9 . The system of  claim 8 , wherein the drive assembly comprises chain drives which engage the mandrel/rod assemblies. 
     
     
         10 . The system of  claim 8 , wherein the rotating assembly spins each mandrel about its respective first axis at a rate of about 5-15 rpm. 
     
     
         11 . The system of  claim 8  wherein the devolatization chamber provides an elevated temperature for driving off solvent from the dispersion coat.