Introduction to Isostatic Molding

Isostatic molding is a suitable alternative to compression and automatic molding techniques for the production of PTFE parts with complex shapes in a wide range of sizes. Compression molding can supply a stock shape which can be machined to obtain the desired shape. The drawback to this option is the 

The flexible nature of the bag renders the definition of its volume difficult when compared to a metallic mold. The shape of the bag may also change during the filling step unless it is supported while being charged. The change in the shape of the bag depends on several factors  

Exertion of pressure on the bag is multidirectional which conforms the resin powder to all patterns and nonuniformities in the bag. Consequently, the surfaces adjacent to the bag are less smooth than those adjacent to the smooth metallic surfaces. The importance of surface formation is one of the considerations that determines the selection of the t5q)e of molding process. 

Isostatic molding is ideal for manufacturing thin long objects from small tubes (5 mm diameter) to very large diameter thin wall tubes (30 cm diameter). Examples include pipe liners, liners for valves and fittings, flanged parts, closed end articles, and a host of other shapes which would require extensive machining. Table 5.3 offers examples of isostatically-molded parts and their applications. 

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