Adaptive Press Casting for Complex Shape Production Using Molten Metal's Pressure Control inside Greensand Mold

摘要

This paper presents a modeling and control of molten metal's pressure using a new type of iron casting.rnWe have developed a greensand mold press casting. In this method, molten metal is directly poured into the lower mold,rnand then pressed to fill the cavity by the upper mold being lowered down. Our past test results showed a casting yield ofrn90%- 95% . During high-speed pressing, filling fluid rapidly increases pressure and flows into the interspace between sandrnparticles. To conduct the pressing velocity design algorithm, a mathematical pressure-model is built by using CFD:rnComputational Fluid Dynamics. The proposed model is based on Bernoulli's theorem considering viscous flow depending onrnfluid temperature. A sequential switching control is proposed from higher velocity to lower velocity, because the pressurernfluctuation has discontinuous variation points. This multi-switching velocity input is changed in accordance with the flow pathrnchange in sequence. Consequently, the effectiveness of the press casting with reasonable quality has been demonstratedrnthrough the experiments.