FEA support structure generation for the additive manufacture of CastForm™ polystyrene patterns

Understanding the nature of part failure when using CastForm™ material for pattern generation is essential in the development of failure avoidance practices. Currently, many approaches employed in both research and industry rely on the use of physical supports to underpin the part, yet there is little research which explores their optimal implementation. In this paper, a detailed empirical investigation examines how the material characteristics of CastForm™ are affected during the thermal infiltration process, and how this may lead to part failure. Using Dynamic Mechanical Thermal Analysis, it is shown that increased temperature reduces the storage modulus of the material, leading to rubber-like behaviour at 60 °C. The findings of this material investigation are used as input for the generation of a linear static FEA model, with which this research demonstrates how physical supports can be optimized in terms of the quantity used, and also their positioning relative to the part. Two industrial case studies illustrate this approach to part production, highlighting both the success of the FEA approach to eliminate part failures, and also the potential to improve knowledge for the process operators in the use of part supports.