Predicting fill patterns for the in-mould coating process for thermoplastic parts

Abstract

In-mould coating (IMC) is an environmentally friendly alternative to painting for injection moulded plastic parts. IMC is carried out by injecting a liquid low viscosity thermoset material onto the surface of the thermoplastic substrate while it is still in the mould. The coating then solidifies and adheres to the substrate. The IMC process is being integrated with conventional thermoplastic injection moulding to improve the part surface quality and to protect it from outdoor exposure. In a previous paper, we presented a Hele–Shaw based mathematical model to simulate the coating flow during the IMC process assuming the coating to be a Newtonian fluid. It has been shown that the coating behaves like a shear thinning fluid. In this paper, a power-law viscosity model is employed to describe the rheological behaviour of the coating material. The continuous deformation of the thermoplastic substrate caused by the coating injection is analysed by means of the PVT relationship of the substrate. The corresponding model is solved using the control volume based finite element method to predict the fill pattern and pressure distribution during the coating flow. The predicted results are compared to experimentally obtained fill patterns. The need to include the ‘edge effect’ is also discussed.

Decreasing the cycle time for in‐mold coating (IMC) of sheet molding compound (SMC) compression molding

“…The basic concept of the IMC process is to integrate priming with the molding process to eliminate emissions and reduce costs . A schematic representation of IMC application on SMC substrate is shown in Fig.…”

Insights into the slip flow phenomena encountered during in-mold coating (IMC) of plastic parts

“…First was the work by Chen et al [7] , who approximated the coating rheology with the two-parameter power law model and assumed that the material did not slip at the bounding walls. This model predicted the fill patterns, but could not predict the filling pressures.…”

Experimental Evaluation of Co-Infusion as a Viable Method for In-Mold Coating of Composite Components

“…When injected onto a cured SMC part, IMC cures and bonds to provide a paint-like surface. Several forms of in-mold coating have been researched, including the metal plating of SMCs [3], and in-mold coating of injection molded plastics [4][5][6][7]. Toro et al [1] established the viability of the use of thermoformable films with the RIDFT process.…”