PA66注塑件组装过程开裂的分析及措施  

Analysis and Measures for Cracking of PA66 Injection Molded Parts in Assembly Process

作　　者：段凯歌 陈章成 王朝 朱辉 泮豪 郑拾玉 郭献级 Duan Kaige;Chen Zhangcheng;Wang Chao;Zhu Hui;Pan Hao;Zheng Shiyu;Guo Xianji(Zhejiang Menred Comfort System Co.,Ltd.,Wenzhou 325000,China)

机构地区：[1]浙江曼瑞德舒适系统有限公司,浙江温州325000

出　　处：《工程塑料应用》2023年第6期80-84,共5页Engineering Plastics Application

摘　　要：尼龙66(PA66)注塑件在冬季组装过程中容易出现开裂现象,影响产品外观质量,分别从注塑前原料的预处理、注塑工艺参数控制(包括料筒温度、喷嘴温度、模具温度、注射压力、保压时间)和注塑后的调湿工艺这几个方面对出现的开裂原因进行了分析。结果表明,注塑件的预处理和注塑工艺满足要求,但缺少注塑后的调湿工艺,冬季组装过程易开裂是由于注塑件注塑后的含水率极低,冬季外界环境湿度较小,注塑件在短时间不能吸收到足够的水分,相应的抗冲击能力较差,无法承受组装过程的冲击力而出现开裂现象。针对这一问题,采用了两种不同的调湿工艺(水煮处理和恒温恒湿处理)对质量分数20%玻璃纤维增强PA66(PA66/20%GF)材料进行处理,分别研究了这两种工艺对PA66/20%GF材料吸水率及弯曲性能和简支梁冲击性能的影响。结果表明,恒温恒湿处理的材料吸水率较低,故弯曲性能稍有降低、冲击性能稍有提升;水煮工艺能大幅度提升材料吸水率,材料的缺口冲击强度因此得到大幅度提升,但弯曲性能下降比较明显。两种工艺均能解决注塑件开裂问题,恒温恒湿工艺耗费时间较长,可应用于需要保留较高弯曲性能的场合,而水煮工艺可大幅缩短调湿时间(95℃,0.5 h),适合对抗冲击要求较高的场合。In winter,nylon 66(PA66)injection molded parts are prone to cracking in assembly process,which affects the appearance quality of the product.The reasons for the cracking were analyzed from the aspects of pre-treatment of raw materials before injection molding,controlling of injection molding process parameters(including barrel temperature,nozzle temperature,mould temperature,injection pressure and holding time)and humidity controlling process after injection molding.The results show that the pre-treatment and injection molding process of the injection molded parts meet the requirements,but there is a lack of humidity controlling process after injection molding.The injection molded parts are prone to cracking during the winter assembly process due to the extremely low water content after injection molding.The humidity of the external environment is low in winter,so the injection molded parts cannot absorb enough water in a short period of time,resulting in poor impact resistance,and cannot withstand the impact force of the assembly process,leading to cracking.In response to this problem,two different humidity controlling processes were used to treat 20 wt%glass fiber reinforced PA66(PA66/20%GF)material,including boiling treatment and constant temperature and humidity treatment.The effects of the two humidity controlling processes on the water absorption,bending and Charpy impact properties of PA66/20%GF material were studied.The results indicate that the material treated by constant temperature and humidity process has low water absorption,resulting in a slight decrease in bending property and a slight improvement in impact resistance.The boiling process can significantly improve the water absorption,so enhance the impact resistance and significantly decrease the bending property.The two processes can solve the cracking problem of the injection molded parts.Constant temperature and humidity process takes a long time and can be used for occasions needing to retain higher bending property.However,the boiling process

关 键 词：尼龙66注塑件 开裂 吸水率 弯曲性能 简支梁冲击性能 

分 类 号：TQ171[化学工程—玻璃工业]