Effect on cooling time in soft tooling process using particle reinforcement with polyurethane mould material

Abstract

Use of conventional flexible polymeric mould materials yields to longer solidification time of (wax/plastic) patterns in soft tooling (ST) process. Thereby, reducing the rapidity of the process to a great extent which is not desirable in present competitive market. In this work, approach of particle reinforcement with mould materials is introduced to increase the productivity of ST process and the resulting cooling time is experimentally investigated in considering a case of manufacturing of a typical wax pattern with aluminium filled polyurethane (PU). It is observed that cooling time is significantly reduced particularly with higher loading condition of aluminium filler due to the increase of equivalent thermal conductivity (ETC) of mould material. But simultaneously, it is also found that the stiffness of mould becomes high due to increase of equivalent modulus of elasticity of mould material. Realising these facts, an extensive experimental study is carried out to find the effect on equivalent thermal properties and modulus of elasticity of PU composites by reinforcing aluminium and graphite particles independently with different loading conditions. The existing models of ETC and modulus of elasticity of composites are also tried to validate based on the experimental findings.