薄壁带筋轮座注射成型表面气纹形成机理与缺陷消除  

Formation Mechanism and Defect Elimination of Air Marks on Surface of Injection Molding of Thin-walled Ribbed Wheel Seat

作　　者：蔡伟南 徐晓[1] 王子秦 夏琴香[1] 肖刚锋[1] Cai Weinan;Xu Xiao;Wang Ziqin;Xia Qinxiang;Xiao Gangfeng(School of Mechanical and Automotive Engineering,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学机械与汽车工程学院,广州510640

出　　处：《工程塑料应用》2022年第2期78-82,95,共6页Engineering Plastics Application

基　　金：2019~2021年度广东省重点领域研发计划项目(2019B090918004)。

摘　　要：以某薄壁带筋轮座件为研究对象,针对零件表面气纹缺陷,基于Moldflow仿真对熔体流动规律和气纹的形成机理进行分析,利用金相显微镜对熔体结合位置冷却后的微观形貌进行观测,对结合位置的气泡与表面气纹的联系进行了分析,结果表明在熔体结合位置缺少相应排气时,熔体前端的空气难以排出,易产生气纹;基于表面气纹缺陷分析,结合模具和产品具体结构,提出增加排气镶件、修改进胶点和调整局部壁厚等解决方案。结果表明,采用修改进胶点至加强筋处同时增加加强筋壁厚的方案,可使熔体最终结合位置从按钮槽附近转移至分型面附近,型腔内气体可从分型面排气槽处排出,能有效避免熔体结合处的困气缺陷。最终通过试模验证,实现了零件表面气纹缺陷的消除。Taking a thin-wall wheel seat with rib as the research object,aiming at the air mark defects on the surface of the part,the melt flow law and the formation mechanism of air marks were analyzed based on Moldflow simulation.The microstructure of the melt after cooling was observed by metallographic microscope,and the relationship between the bubbles and the air marks on the surface was analyzed.The results show that the air at the front end of the melt is difficult to be discharged and gas lines are easy to occur when there is no corresponding exhaust at the joint position of the melt.Based on the analysis of surface air mark defects,combined with the mold and product structure,some solutions were put forward,such as adding exhaust insert,modifying glue point and adjusting local wall thickness.The results show that by modifying the gate location to the stiffener and increasing the wall thickness of the stiffener,the final joint position of the melt can be transferred from near the button groove to near the parting surface,and the gas in the cavity can be discharged from the exhaust groove of the parting surface,which can effectively avoid the gas trapping defect at the melt bonding position.Finally,the elimination of air mark defects on the surface of parts was realized through mold testing.

关 键 词：薄壁带筋轮座 注射成型 表面气纹 机理分析 气纹消除 

分 类 号：TQ320.66[化学工程—合成树脂塑料工业]