OPTIMIZATION OF RISER DESIGNS WITH INSULATING SLEEVES TO ACHIEVE MINIMUM COST.

A model is developed for the design and costs of risers for metal castings. The model determines riser height and diameter, riser cost, optimum design and minimum cost, and it compares the costs of risers incorporating insulating sleeves with risers without sleeves. The model includes costs for the sleeve, the cost for removing the riser, conversion costs for providing molten metal in the foundry, and a cost for the metal lost during the removal of the riser. Results of calculations for aluminum casting alloy 356. 0 are presented, but the model is suitable for general applications. The savings possible by using the sleeves are very substantial.