3D-printed rib-enforced shell sand mold for aluminum castings

A rib-enforced shell mold for castings is proposed to replace the traditional dense mold. The 3D printing methods of sand mold make this new mold design a reality. The rib-enforced shell mold has been applied to cast a stress frame specimen of Al alloy A356. The effects of rib-enforced shell sand mold and traditional dense mold on the cooling of this casting have been investigated and compared. The results show that the cooling efficiency of the casting increases significantly by using rib-enforced shell mold, and approximately 40% cooling time is saved in natural condition and 35% further is saved in air blowing condition for the stress frame specimen before shakeout. This mold makes it possible to adjust the cooling condition of interested locations. It ensures fast and uniform cooling of the casting which can improve production efficiency and reduce deformation and residual stresses of the casting. Temperature distribution in the rib-enforced shell sand mold during the solidification was measured by an infrared imaging camera. The produced casting has good dimensional accuracy and surface quality. Meanwhile, nine-tenths of the sand is saved per mold.