The thermoforming process involves three stages, sheet reheat, forming and solidification. A polymeric sheet is heated in an oven to the desired forming temperature distribution. The sheet is then deformed to take the shape of the mould cavity and subsequently solidified. This work includes the modelling and experimental validation of both the sheet reheat and vacuum forming stages. The part considered is moulded in a box shape cavity mould that is supplied by Quality Thermoform. The modelling simulations and the corresponding experimental trials were performed at the Industrial Materials Institute. The heat transfer in the oven is modelled by employing combined radiation and natural convection. The sheet forming is modelled with a non-isothermal viscoelastic constitutive equation. The process stages are modelled in sequence, namely sheet reheat, sag and vacuum forming.
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