Despite the advantages associated with the processing method, the long cycle time required by
the rotational molding process has confounded the overall success of this technology. Due to the
complex rotation of the mold, heating and cooling are most commonly achieved by convection to the
external surfaces of the mold using air as the transfer medium. The product cycle times are restricted by the time required to heat up and cool down the mold and the product by the slow heat convection process. Molds with extended surfaces or fins have the potential to enhance the heat transfer and reduce the cycle time by increasing the surface area. Despite the fact that this rotational molding technique has been developed for over three decades, research efforts on rotational molds with extended surfaces [8] have been limited. The only work done was carried out by Abdullah et al. [9], who studied the effects of a square pin and a pyramid roughness element on the convective heat transfer of a flat plate.