高分子板材多点热成形中的压痕及其影响因素

Influence factors on dimpling in multi-point thermoforming for polymer sheet

提出了一种专门用于热塑性高分子板材的多点热成形工艺,确定了聚碳酸酯板材的本构方程参数,建立了聚碳酸酯板材多点热成形的有限元模型。通过数值模拟分析了成形件表面压痕的影响因素,结果表明,减小多点模具基本体的尺寸以及增加基本体球头半径可以有效地抑制成形件表面的压痕。在多点热成形试验机上进行了聚碳酸酯板材的成形试验,结果表明:合理地选择多点模具基本体尺寸可以有效地抑制或消除成形件表面的压痕,提高成形精度。

Multi-point Thermoforming （MPTF） is a new flexible technique for forming three dimensional polymer sheet parts. The parameters of polycarbonate according to G＇Sell＇s constitutive equation were determined and a Finite Element Model（FEM） of MPTF process of polymer sheet was established. A series of numerical simulations were carried out to analyze the influence factors on dimpling in MPTF. The results show that the dimples on the formed part diminish with the decrease of punch element size. The large punch element radius can improve the surface quality and the shape accuracy of the formed part. Experiments were performed on a MPTF experimental setup and the results show that proper selection of the dimension of multi-point die can significantly improve the forming quality.