Rotational molding heat transfer—an update

In earlier works, a complicated circulation model was chosen to describe heat transfer to powder in a rotating mold. In order to satisfy the model, an experimentally‐determined empty mold temperature response was used. An alternate heat transfer model, in which the powder is assumed to be in static contact with the mold surface at all times, shows significant temperature deviation from the earlier model. The predicted time for complete sinter‐melting is much closer to earlier experimental data than the predicted times from the circulation model. The melting time is seen to follow the form given by the Goodman penetration model. Complete heating and cooling profiles are more easily generated using this static model, and a new interpretation of the air cooling step in the heat transfer cycle results.