Solving of Thermoplastic-Carbon Bonding Issue Using Numerical Simulations

The aim of this study was to elaborate on the methods of constructing combined components of a car mirror. The components were made of materials with different thermal expansion coefficient. The basis for the research were numerical simulations prepared in Moldex 3D software. The external cover of a mirror would be made of carbon composite based on epoxy resin (hereafter referred to as carbon), and the internal insert would be made of ABS. The adhesive bonding applied did not provide appropriate properties and led to breaks during usage. After carrying out moldflows it was found that the areas of breaks were determined by the places where fronts of flowing material met during the injection. The cause of breaking was diametrically different thermal expansion of both materials. This induced significant stresses in the adhesive layer. Finally, the effective solution was to change the geometry of the mirror insert made of thermoplastic ABS.