含微棱柱阵列结构表面的注射成型脱模  

Demolding deformation of surface micro-prism array structure part based on injection molding

作　　者：丁涛 杨冬娇 刘介珍[1] 翁灿[1] DING Tao;YANG Dong-jiao;LIU Jie-zhen;WENG Can(School of Mechanical and Electrical Engineering, Central South University, Changsha 410083, China)

机构地区：[1]中南大学机电工程学院,湖南长沙410083

出　　处：《光学精密工程》2020年第11期2466-2477,共12页Optics and Precision Engineering

基　　金：国家自然科学基金面上项目(No.51775562)。

摘　　要：为了研究表面微结构成型质量的影响因素,设计并制备了3种深宽比的微正四棱柱结构,并对聚合物材料、微结构深宽比、脱模工艺参数、镍模芯表面抗黏处理等影响因素进行注射成型脱模实验研究。首先,采用PP,COC,PMMA等材料研究了获得目标深宽比微结构的难易程度。以PP材料为例分析了在3种深宽比下的脱模成型质量,分别从保压压力、脱模温度两方面讨论对脱模变形的影响。最后,分析比较镍模芯经过抗黏处理前后成型的微结构形貌尺寸。PP能够顺利获得近似目标深宽比的微结构,COC脱模后微结构发生折断变形,高度平均只有17.0μm左右,PMMA成型后微结构也发生断裂且黏附在模芯微孔中。脱模变形随着深宽比的增加而趋于严重,且当深宽比较大时,微结构易发生倾斜变形。提高保压压力,微结构平均高度从约25.0μm增加到约87.0μm,但当保压压力过高时微结构出现翘曲变形;随着脱模温度的升高,保留完整的微棱柱比例分别为55%,60%,30%,10%。镍模芯经过抗黏处理后所成型微结构的尺寸更加接近目标值。COC由于本身断裂伸长率较小而具有较大的脆性,而PMMA本身的表面能较大则具有较强的黏附性。深宽比增加使得脱模时微结构顶部黏附力与后期摩擦力均会增加。合理增加保压压力、降低脱模温度与镍模芯经过抗黏处理均能有效提高脱模成型质量,但过高的保压压力会造成微结构内应力增加,产生翘曲。To study the influence factors of surface microstructure quality,three micro quadrangular structures with different aspect ratios were designed and prepared using an injection molding experiment.The factors influencing the demolding quality of this experiment,such as polymer materials,microstructure aspect ratios,demolding processing parameters,and if the nickel inserts were subjected to anti-sticking treatment,were studied.First,the difficulty of obtaining the target aspect ratio microstructure was examined for polypropylene(PP),cycloolefin copolymer(COC),and polymethyl methacrylate(PMMA).Next,using the PP material as an example,the forming quality with different aspect ratios was studied.Then,the influence on demolding deformation was discussed with respect to packing pressure and demolding temperature.Finally,the microstructure shape and size of the nickel inserts before and after undergoing anti-sticking treatment were compared.It was possible to obtain PP microstructures that approximated the target aspect ratio successfully.However,the COC microstructures were broken and deformed after demolding,with an average height of approximately 17.0μm.Meanwhile,the PMMA microstructures were also broken and adhered to the nickel cavities.The demolding deformation tended to be worse with the increase of the aspect ratio,and the microstructure was prone to inclined deformation when it was large.The average height of the microstructure increased from 25.0μm to 87.0μm when the packing pressure increased,but the microstructure warped when the packing pressure was too high.As the demolding temperature increased,the rate of retained micro prism was 55%,60%,30%,and 10%.The size of the nickel insert microstructure was closest to the target size after the anti-sticking treatment.The COC was brittle due to its low elongation at break,while the PMMA showed strong adhesion due to its high surface energy.With the increase of the aspect ratio,the adhesion force at the top of the microstructure and the friction force at the later

关 键 词：表面微结构 注射成型 脱模变形 聚合物材料 深宽比 脱模工艺参数 抗黏处理 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]