Investigation on Material Parameters for Modeling of Thermal Binder Removal Process in a Powder-Binder Mixture

Abstract

Removal of polymeric binder in a powder-binder mixture is a widely used process in the powder forming based manufacturing technologies, such as powder injection molding, slurry or sol-gel casting, tape casting, hot embossing, and binder jetted 3D printing. Among lots of binder removal approaches, thermal debinding is one of the most common methodology for removing the binders in a powder-binder compact before the consolidation process for the powder compact. It is a complicated process combining binder evaporation, liquid transport, gas transport, pyrolysis of binder, and heat transfer in a porous structure. In this work, the mathematical model for explaining the combination of several physical phenomenon in thermal debinding processing has been studied while considering the physical models for mass transport and heat transfer in porous media. A system for determining the material parameters in the model have been established, which highly relates to describing the binder removal phenomenon accurately. The material parameters for a powder-binder mixture have been determined through experiments and phenomenological models. Furthermore, the finite element simulation for polymeric binder removal in a porous media has been performed using a commercial software based on the accomplished mathematical model. The simulation results have been verified by comparison studies with experimental results showing good agreements with a maximum error less than 10%. The results indicate that the approaches for determination of material parameters proposed in this work contribute to modeling and predicting the binder removal process accurately. This work also helps to understand the mechanisms and physical phenomenon during the binder removal process, and to predict and optimize the binder removal process without trial-and-errors. It can contribute to various manufacturing industrial areas (i.e. slurry casting, sol-gel casting, powder metallurgy, powder injection molding, binder jetted 3D printing, etc.), providing an efficient way to predict and optimize of the binder removal process.