Research on the elastic cushion conditions in multi-point thermoforming for polymer sheet

Multi-point thermoforming is a new flexible technique for manufacturing three-dimensional polymer sheet parts. The fixed die utilized in conventional thermoforming process is replaced by a multi-point die, which can be reconfigured rapidly and nearly cost-free. In the present study, the effects of the elastic conditions on the surface quality and shape accuracy of the formed workpiece have been investigated through experiments and numerical simulations. The results show that an elastic cushion with proper thickness and hardness can significantly improve the surface quality of the workpiece. It has also been found that the application of lubrication can improve the shape accuracy of the formed workpiece.