聚碳酸酯板多点热成形起皱的影响因素

为了研究聚碳酸酯(PC)板多点热成形起皱的影响因素,介绍了PC板多点热成形的原理,测试了PC板的玻璃态转变温度,获得了不同温度下PC板的应力松弛曲线,建立了球面件多点热成形有限元模型,并得到了球形面多点热成形起皱的模拟结果。同时,研究了板厚、半径和成形温度对起皱的影响。数值模拟结果表明:板料越厚、半径越大、成形温度越低,均导致球面件起皱越轻微。此外,获得了不同板厚、半径和成形温度条件下PC板的无皱曲成形极限,并开展了PC板多点热成形试验,结果验证了数值模拟的准确性和无皱曲成形极限图的实用性。

Influence factors on wrinkle of polycarbonate sheet in multi-point thermoforming

In order to investigate the influence factors on wrinkle of polycarbonate ( PC) sheet in multi-point thermoforming ( MPTF) , the principle of multi-point thermoforming for sheet was introduced, and the glass transition temperature of PC sheet was tested. Then, the stress relaxation curves of PC sheet under different temperatures were obtained, and the finite element model of multi-point thermoforming for spherical part was built. At last, the numerical simulation of wrinkle for spherical part in multi-point thermoforming was got, and the influences of thickness, radius and forming temperature on the wrinkle were researched. The numerical simulation results show that a thic-ker sheet, or a larger radius, or a lower forming temperature can bring a smaller wrinkles. In addition, the non-wrinkle FLD of PC sheet under different sheet thicknesses, radius and deformation temperatures was obtained respectively, and the experiments of multi-point ther-moforming for PC sheet were carried out. Finally, the validity of simulated results and practicability of non-wrinkle forming limited dia-gram were verified by experimental results.