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Technology for the Advancement of Die Casting Tooling
High pressure die casting is an industrial metal casting process used to manufacture goods for use in many aspects of society. Within this manufacturing process, the tooling is subjected to chemical attack from molten aluminum while also being responsible for heat removal during solidification. The purpose of this study is to develop and test materials that allow the tools to better withstand the chemical attack, and to develop design rules to guide the use of additive manufacturing for improving the heat exchange function of by way of conformal cooling.
Within the material studies, a gooseneck with a niobium lining was developed to allow the successful implementation of hot chamber aluminum die casting. In addition, a manufacturing plan is described that will allow the niobium gooseneck design to be easily sourced by die casting companies. The material studies also included dunk testing of several coatings, including a plasma assisted chemical vapor deposition silicon doped diamond like carbon (PACVD Si-DLC). The Si-DLC coating performed the best in the dunk testing as compared to bare and nitrocarburized tool steel, and a number of other coating architectures.
Within the study of additively manufactured conformal cooling design, a finite difference model is developed that allows a simulated experiment that produced a number of useful equations that guide the design of die casting tooling. During the development of the models, it was discovered that little is known regarding the friction factors of additively manufactured steel pipes, so a factorial experiment was employed to empirically determine said friction factors. Charts allowing design engineers to quickly determine pressure drops and heat transfer coefficients of conformal cooling designs was produced as well.