3D Computation of reactive moulding processes

Abstract

International audienceElectrical equipment for medium and high voltage is manufactured using reactive moulding process. During mould filling, air bubbles or weld-lines can appear which may be a huge problem for electrical insulation devices. Moreover, the use of thermoset materials induces delamination due to the resin's shrinkage. Product development delays can be reduced using numerical tools to simulate part forming process. In this paper, we present a three dimensional finite element analysis of the filling and curing stages of reactive moulding process. During the first stage, flow computation takes into account heat transfer and the curing reaction according to appropriate models. In the curing phase, the evolution of the degree of cure is coupled with an evolution model of the glass transition temperature. Taking in account his coupling phenomenon permits the computation of a more realistic curing kinetic and modelling of the slowdown at vitrification. The thermal field prediction is then more accurate. To validate this approach, experiments were performed. A comparison with computational results shows a good agreement in filling and temperature evolution inside the cavity

Multiphysics for Simulation of Forming Processes

“…where T 0 g and T 1 g are glass transition temperature values of the uncured and fully cured resin, and κ is an adjustable structure dependent parameter. To illustrate what type of computations use these features, we consider the overmolding of an electrical part with an epoxy resin, Fig.3 [13].…”

“…Numerical results obtained in overmolding of an electrical part with an epoxy resin: (a) comparison of experimental end of fill positions and numerical predictions for two different filling configurations; (b) temperature (left) and degree of curing (right) at the end of filling (above) and at the end of the post-filling (below) stages[13].…”