EPDM包覆层注射成型模拟及工艺参数研究

为了提高三元乙丙橡胶(EPDM)包覆层注射成型工艺的研发效率,通过数值模拟和实验验证相结合的方式研究了EPDM的流动规律并优选出合适的工艺参数。采用Carreau模型拟合EPDM的流变特性方程,使用Moldflow软件模拟EPDM包覆层的注射成型过程;模拟过程选择了合适的浇口位置,预测了气穴、熔接线位置以及前沿温度的变化,结果与实验一致,气穴易于在弧形顶部形成,同时选择侧面对称的双注射口更有助于成型;分析了温度、压力以及流动速率对填充过程的影响,得到初步的预测成型参数。基于此,进一步通过实验验证得到了合格产品的工艺参数。使用拉伸实验研究所选范围的压力和注射速率对包覆层制品质量的影响,结果表明,合适的工艺参数为:注压温度170℃,镀铬模具温度170℃,注压最大压力30MPa,注压量为148cm³,注压速率为12mm/s。

Research on Injection Molding Simulation and Process Parameters of EPDM Coating

In order to improve the development efficiency of ethylene propylene diene monomer(EPDM)rubber coating injection molding process,the flow law of EPDM was studied by combination of numerical simulation and experimental verification and appropriate process parameters were optimized.The rheological properties of EPDM were modeled using the Carreau mode,which was introduced into Moldflow software to simulate the injection molding process of EPDM coating.The simulation obtains the appropriate gate position,and predicts the air pocket,weld line position and the change of front temperature,which is consistent with the experiment.Airhole are easy to form at the top of the arc,and the choice of side-symmetrical double injection ports is more conducive to molding.The influence of temperature,pressure and flow rate on the filling process was analyzed,and preliminary prediction molding parameters were obtained.On the basis of the fitting results,the process parameters of qualified products were further verified by experiments.The influence of the selected pressure and injection rate on the quality of coated products was studied by tensile test.The results show that the appropriate process parameters are as follows:injection temperature 170℃,chrome-plating mold temperature 170℃,maximum injection pressure 30MPa,injection volume 148cm³,and injection rate 12mm/s.