Design of the plunger-assistant compressed air thermoforming mould for the PP cup

For the thermoforming products with large extension ratio, the differences of the mould structure design and forming method during the thermoforming will result in the no uniform wall thickness of products. The no uniform wall thickness influences the product appearance and service performance. In this paper, taken the PP cup with large extension ratio (H/D≈1.8) as the experiment product, the plunger-assistant compressed air thermoforming mould is designed. The major feature of this mould is using the plunger to preliminary elongation the heating PP material, and then using the compressed air forming method. By this way, the product with uniform thickness and the product quality can be obtained.