This article models bubble removal in centrifugal casting of the thermosetting silicone polydimethylsiloxane (PDMS). Given spin speeds, mold geometry, and resin properties for centrifugal casting, it is possible to predict the amount of spin time required to produce bubble-free parts. For the particular conditions and materials considered in this work, required spin times range from seconds to minutes. The model itself balances two complementary physical behaviors: bubble dissolution and buoyancy. Diffusion dominates the removal of small bubbles below a critical size, while buoyancy dominates the removal of bubbles above a critical size. To simulate the removal of bubbles from a spinning solution, two first-order nonlinear differential equations are solved numerically. To verify simulated results, designed sets of experiments related the number of remaining bubbles in cured parts to spin times and speeds. Dow Corning Sylgard 184, Sylgard 186, and 3-6121 were the silicones tested in this work.
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