The quality of spin cast products and mould life are critically dependent on the thermal conditions they are exposed to. An investigation was carried out on the effect of air-cooling induced by the spinning of the mould and its consequences on the thermal process. A system was developed to optimise the thermal process during casting, utilising a theoretical analysis of the air-flow characteristics in a cooling tube submerged in a silicon mould and the characteristics of convection heat transfer associated with the mould and cast part. A numerical simulation of the casting process was also used in this process. The effect of the developed system on the thermal process was determined experimentally and it was found that a system of air-cooling, automatically induced from the spinning of the mould, is feasible in optimization of the thermal process.