Fabrication of Parts from Compounds

In comparison with unfilled PTFE, compounds can be sintered by using shorter sintering cycles due to the increase in thermal conductivity of the preform by incorporation of fillers (Table 3.10). 

Properties of granular PTFE compounds are presented in this section. A few points should be noted about filled PTFE compounds. Shape and size of the filler and resin particles, type of molding process, and processing conditions all influence the properties of parts made from compounds. Properties of compounds made with non-spherical particles are 

Compound Type Unfilled PTFE 15% wt. Glass Fiber 15% wt. Glass Fiber 60 /o wt Bronze 23% Carbon/ 2% Graphite (wt) 23% Carbon/ 2% Graphite (wt) 

The volume fraction of the fillers in the compound depends on its specific gravity. A higher weight fraction of heavier fillers such as bronze can be incorporated than lighter additives like glass. Physical properties of the compound deteriorate with increase in the volume fiaction of the filler as illustrated in Fig. 3.4. 

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