CAREER: The Production of High Value, Defect-free Metal Castings through Model-based Design and Additive Manufacturing of Sand Molds

This Faculty Early Career Development (CAREER) grant focuses on the study of metal casting using model-based design and three-dimensional printed sand molds. Metal casting involves pouring of molten metal in a mold made of sand. It is one of the oldest and most widely used manufacturing processes in the production of parts and components for many industrial applications. However, traditional metal casting suffers from high scrap rates because it is still regarded as a process that is empirically designed and with high uncertainty even in controlled processing environments. Due to the nature of the two-dimensional geometry of pathways for the molten metal, turbulent flow traps air in the melt and causes defects in the solidified castings. This results in poor mechanical properties along with additional costs and energy to repair or scrap the castings. This project conducts fundamental research to enable new numerical models and computational capabilities to study the complex relationships between the three-dimensional geometry of the sand mold and reduction in defects in the sand castings. This research is complemented by an integrated educational and outreach program based on new course development to be strategically deployed across the U.S through a network of foundry educators. In addition, a manufacturing education center at the home institution is leveraged for underrepresented minority and K-12 student outreach.

The goal of this research is to understand the effects of 3D freeform gating and riser geometry in sand casting on reducing defects and improving the mechanical properties of metal castings. Turbulent filling of molten metal results in the formation of oxide bifilms, air entrapment and porosity in castings, which adversely impact their mechanical performance. The research objectives of the project are: (1) Understand the effects of 3D free-form gating and riser design on air entrapment and formation of oxide bifilms during mold filling, and (2) Characterize the relationship between 3D freeform gating and riser system and solidification behavior and their impact on mechanical strength. This project leverages an additive manufacturing process, namely binder-jetting of foundry sand or 3D sand-printing for the fabrication of sand molds for metal casting. This research establishes a fundamental understanding of 3D gating and riser design geometries in sand molds for defect-free metal castings. Melt flow velocity, fluid dynamics, solidification rate, and microscopic properties such as dendrite arm spacing, inclusions and porosity are investigated. Design principles for 3D gating and riser geometries that can be achieved by 3D sand-printing of molds are developed and validated. This project enables the PI to advance the knowledge of metal casting science, computational fluid dynamics modeling and in-process monitoring of the casting process and establishes the foundation for a long-term career in advanced manufacturing.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.