Molten Metal Pressure Control for Defect Prevention with Generalized Predictive Control in Rapid Press Casting

Abstract

This paper presents a technique for controlling the pressure of molten metal when using a new type of the iron production method called greensand mold press casting to realize high productivity and obtain high-quality castings. In this method, molten metal is poured into a lower mold first, and the after upper mold is moved down toward the lower mold, then both molds are matched. Casting defects such as metal penetration are often caused by the high pressure in the high-velocity pressing process. Therefore, we proposed a pressure control method with a mathematical model of molten metal pressure, and with it we achieved confirmation simulation of the successful pressing production at the different pressing condition such as mold shape. Results show that the proposed pressing production considering the generalized predictive control: GPC can realize sound, penetration-free casting production under the pressure constraint for defect prevention. Here a simple simulation of model predictive pressing control and water pressing experiment using feed-forward motion input calculated by off-line GPC are presented. Discussions of the theoretical control design for the process as well as its practical confirmation result of water pressure behavior in pressing experiment are concluded.