Processing of Granular Resins

Granular PTFE resins are most frequently processed by compression molding using a technique similar to that common in powder metallurgy and by ram extrusion. Each of these processes requires a specific type of granular resin. 

FIGURE 4.1 Mold assembly for small- to medium-size billets. (Courtesy of DuPont.) 

FIGURE 4.2 Compression molding press for PTFE billets. 

During the compression of the PTFE powder both plastic and elastic deformations occur. At low pressures the particles slip, slide, and tumble in place to align themselves into the best possible array for packing. With increasing pressure, contact points between adjacent particles are established and further enlarged by plastic deformation. Plastic deformation also eliminates internal particle voids. 

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