Abstract: A new heat transfer theoretical model was established for rotation molding of spherical hollow plastic parts, and a numerical computation was performed using Fluent software. Heat conduction of the mold, heat conduction, melting and crystallization of the plastic layer, and convective heat transfer of internal air were coupled for the solution in the model. Temperatures at outer wall of the mold and of the internal air were obtained by numerical computation, which were in good agreement with those by experiment. In addition, cycle times under different heating temperatures, and convective heat transfer coefficients were calculated so that effect of these parameters on cycle time could be determined. By increasing these parameters the cycle time could be reduced.

Key words: rotational molding, cycle time, heat transfer analysis, numerical computation, Fluent software