Associativity modelling of a mould assembly for expandable polystyrene foam

The design and fabrication of a mould for expandable polystyrene (EPS) buffers involves an approach which is radically different from that associated with conventional plastic injection moulding. This is because the EPS mould design encompasses both the classical tooling specifications and considerations of the actual moulding process itself. This paper discusses the notion of associativity modelling in the CAD design of a mould assembly for the manufacture of EPS buffers. This modelling paradigm aims to integrate 5 mould design factors with 25 process (moulding) parameters. Through a better understanding of the interactions between design factors and process parameters, and among the process parameters themselves, a harmonious decision table can be derived which compromises the competing demands of factors and parameters. Because of the visibility of the interactions among parameters, the notion of associativity modelling offers the designer a better insight into mould assembly design, leading to practical mould design solutions that harmonize the functions of the different sub-assemblies.