Novel riser designs via 3D sand printing to improve casting performance

Abstract

3D sand printing (3DSP) has created a new era for sand casting applications by introducing additively manufactured complex 3D sand molds and cores. It has also enabled the design and manufacturing of complex rigging (gating and feeding) systems using non-conventional design rules which were not previously feasible. In this research, two novel riser designs, ellipsoid and spherical risers, along with traditional cylindrical risers are investigated to understand their effects on the solidification time and entrained air volume fraction in Aluminum alloy (A319) castings. Computational simulations are presented to understand the viability of complex riser shapes by comparing critical parameters such as fluid temperature during filling, solidification, and cooling. In addition, solid fraction (SF) and entrained air volume fraction are also studied during filling and solidification. The results for spherical riser performance showed a 7% increase in feeding time during solidification along with a 47.27% reduction in entrained air volume fraction. The ellipsoid riser studied in this research also showed identical solidification time at half the volume of the conventional cylindrical riser. This indicated a 26.5% increase in casting yield. These riser designs will not only facilitate the design optimization of the casting but also improve the casting performance (feeding, solidification) for difficult to cast materials and geometries.