Sheet Moulding Compound (SMC)

Materials used for compression moulding are either in the form of a dough-like substance or in sheet form.  Both forms are composed of resin, chopped glass fibres, a catalyst and a release agent.

Sheet Moulding Compound (SMC) is in the form of a plastic sheet that has not been cured, i.e. finally hardened.  Shaping of SMC is achieved by placing a sheet of the material between the heated plug and yoke of a compression moulding machine.  The plug forces the SMC to take up the shape of the space between the plug and yoke.  Heat from the compression moulding machine cures and hardens the plastic.