Finite element analysis of a coating architecture for glass-molding dies

Finite element analysis (FEA) is being used as an integral part of an overall research program that is being conducted to develop a non-sticking, oxidation- and wear-resistant coating system for glass-molding dies and forming tools. This non-linear thermomechanical FEA consists of two parts: (1) a global analysis using a coupled thermomechanical model of the complete die to predict the locations where the die experiences extreme stress/strain condition during molding cycles; and (2) a local analysis of the die coating used to protect the die at those positions where extreme conditions were predicted by the global analysis, to analyze the stresses generated in the coating system during a simulated glass-molding process. This paper outlines the methodology developed in this work, which can be used to explore the effects of die geometry, die material, and coating materials on the integrity, reliability and performance of a coated die. This methodology may also be helpful for investigation of the mechanisms relating to the thermal fatigue problem. The preliminary results presented here demonstrate that it is possible to find an optimized coating architecture with optimal stress transition from the substrate to the outmost working layer by selecting appropriate coating materials and engineering the compositional gradients of the functionally graded material (FGM) intermediate layer.