We present a detailed theoretical model of the rotational molding process, and identify the key dimensionaless groups affecting the process cycle time. This theoretical model is employed to create differential and lumped parameter numerical models, as well as a simple closed form estimate for the time required for complete powder deposition. Both numerical models give results that are in very good agreement with experimental data available in the literature. The closed form solution gives good predictions over a wide range of processing parameters. In addition, the effects of variations in the dimensionaless groups on processing time are evaluated.