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

Finite element analysis (FEA) is being used as an integral part of an overa ll research program that is being conducted to develop a non-sticking, oxid ation- and wear-resistant coating system for glass-molding dies and forming tools. This non-linear thermomechanical FEA consists of two parts: (1) a g lobal analysis using a coupled thermomechanical model of the complete die t o predict the locations where the die experiences extreme stress/strain con dition during molding cycles; and (2) a local analysis of the die coating u sed to protect the die at those positions where extreme conditions were pre dicted by the global analysis, to analyze the stresses generated in the coa ting system during a simulated glass-molding process. This paper outlines t he methodology developed in this work, which can be used to explore the eff ects 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 pos sible to find an optimized coating architecture with optimal stress transit ion from the substrate to the outmost working layer by selecting appropriat e coating materials and engineering the compositional gradients of the func tionally graded material (FGM) intermediate layer. (C) 2001 Elsevier Scienc e B.V. All rights reserved.