通过Moldflow仿真软件建立了汽车侧踏板聚丙烯/三元乙丙烯（PP/EPDM）复合材料端盖注射成型仿真模型，采用析因设计筛选出对工件翘曲、体积收缩、表面缩痕等缺陷影响最显著的主因子与交互因子，应用正交试验设计方法模拟得到最佳注射成型工艺，并进行了验证。结果表明：对目标值影响显著的主因子为熔体温度、模具温度、注射时间、保压时间和保压压力，交互因子为熔体温度与模具温度、注射时间与保压时间；最优注射成型工艺为熔体温度220℃、模具温度40℃、注射时间2 s、保压时间25 s、保压压力60 MPa，模拟得到的最大翘曲量比原工艺方案的减小了33.21%，体积收缩率降低了39.61%，表面质量显著提高。

The simulation model of injection molding of automotive rocker panel end cap polypropylene/ethylene propylene diene monomer (PP/EPDM) composite was established by Moldflow software. Main factors and interaction factors affecting warping, volume shrinkage, surface sink marks of the workpiece were filtered by factorial design. The optimal injection molding process was simulated by orthogonal test design method and verified. The results show that the main factors affecting the target values were melt temperature, mold temperature, injection time, packing time and packing pressure. The interaction factors were melt temperature and mold temperature, injection time and packing time. The optimal injection molding process was as follows:melt temperature of 220℃, mold temperature of 40℃, injection time of 2 s, packing time of 25 s and packing pressure of 60 MPa. Comparing with the original process, the maximum warpage decreased by 33.21%, volume shrinkage was reduced by 39.61%, and the surface quality was improved significantly.