1、第 15 卷 第 9 期 精 密 成 形 工 程 2023 年 9 月 JOURNAL OF NETSHAPE FORMING ENGINEERING 47 收稿日期:2023-08-02 Received:2023-08-02 基金项目:宁波市科技创新 2025 重大专项(2021Z044);宁波市科技创新 2025 重大专项(2023Z029);浙江省“尖兵”“领雁”研发攻关计划(2022C01069)Fund:The Key Project of Science and Technology Innovation 2025 of Ningbo(2021Z044);the Key Proj
2、ect of Science and Technology Innovation 2025 of Ningbo(2023Z029);the Pioneer and Leading Goose R&D Program of Zhejiang Prov-ince(2022C01069)引文格式:高若翔,焦晓龙,阮剑波,等.超厚壁聚合物光学产品多次注射-压缩成形技术研究J.精密成形工程,2023,15(9):47-56.GAO Ruo-xiang,JIAO Xiao-long,RUAN Jian-bo,et al.Multilayer Injection-compression Molding Pr
3、ocess of Ultra-thick-walled Polymer Optical ProductsJ.Journal of Netshape Forming Engineering,2023,15(9):47-56.超厚壁聚合物光学产品多次注射-压缩 成形技术研究 高若翔1,焦晓龙2,阮剑波2,陈豪1,周期峰3,赵朋1*(1.浙江大学 机械工程学院,杭州 310030;2.海天塑机集团有限公司,浙江 宁波 315821;3.杭州友成机工有限公司,杭州 311241)摘要:目的目的 针对聚合物材料在注射成形过程中密度变化大,在成形超厚壁光学产品时容易产生收缩、气泡等缺陷,难以满足高性能成形
4、需求等问题,提出了一种新型多次注射-压缩成形工艺,并研究了成形次数、压缩距离等参数对厚壁光学产品成形形变和双折射的影响规律。方法方法 设计并制造了相应的多次注射-压缩成形模具,将超厚产品分解为若干个薄壁制件,通过连续多次注射可以实现任意厚度与分层方式的产品成形,从而实现厚壁光学产品的成形,最大成形厚度可达 100 mm。在此基础上,通过实验对多次注射-压缩成形的关键参数进行了研究。结果结果 多次注射可改变产品的变形形式,由单次注射产品的翘曲形变转变为收缩形变,且形变值减小达 70.3%。随着压缩距离的增大,产品形变呈现先减小后增大的趋势,单次注射-压缩成形产品形变值最大可减小 32.7%,而多
5、次注射-压缩产品最小收缩形变值仅为未压缩产品的 1.1%。此外,与注射成形相比,压缩工艺可以减小产品的双折射,而压缩距离对双折射的影响不显著。结论结论 多次注射可以对单次注射成形缺陷进行补偿。通过注射-压缩成形工艺,可显著减小产品的形变,同时提高光学性能,实现超厚壁光学产品的高性能成形。关键词:多次注射;超厚壁产品;注射-压缩;收缩形变;模具设计 DOI:10.3969/j.issn.1674-6457.2023.09.006 中图分类号:TQ320.66 文献标识码:A 文章编号:1674-6457(2023)09-0047-10 Multilayer Injection-compressi
6、on Molding Process of Ultra-thick-walled Polymer Optical Products GAO Ruo-xiang1,JIAO Xiao-long2,RUAN Jian-bo2,CHEN Hao1,ZHOU Qi-feng3,ZHAO Peng1*(1.School of Mechanical Engineering,Zhejiang University,Hangzhou 310030,China;2.Haitian Plastic Machinery Co.,Ltd.,Zhejiang Ningbo 315821,China;3.Hangzhou
7、 Yusei Machinery Co.,Ltd.,Hangzhou 311241,China)ABSTRACT:Due to the large density changes in the injection molding process of polymer materials,defects such as shrinkage and bubbles are prone to occur during molding of ultra-thick-walled optical products,and it is difficult to meet the high-per-复合材料
8、成形 48 精 密 成 形 工 程 2023 年 9 月 formance molding requirements.For this reason,the work aims to propose a novel multilayer injection-compression molding process and study the effect of injection times,compression distance and other parameters on the deformation and birefringence of thick-walled optical
9、products.A novel multilayer injection-compression mold was designed and manufactured,which de-composed ultra-thick products into several thin-walled parts.Through continuous multilayer injections,the process achieved the molding of products with any desired thicknesses and layering scheme,enabling t
10、he fabrication of thick-walled optical products with a maximum thickness up to 100 mm.The key parameters of multilayer injection-compression molding were experimentally studied.Multilayer injections could change the deformation form of the products,from warping deformation of single injection produc
11、ts to shrinkage deformation,and the deformation value was reduced by 70.3%.As the compression distance increased,the deformation of the products presented a trend of decreasing firstly and then increasing.The deformation value of single injec-tion-compression molding products could be reduced by a m
12、aximum of 32.7%,while the minimum shrinkage deformation of multilayer injection-compression products was only 1.1%of uncompressed products.In addition,compared with injection molding,the compression process could reduce the birefringence of the products,but the compression distance had no signifi-ca
13、nt effect on the birefringence.Multilayer injections can realize the compensation for defects in single injection molding.At the same time,through the injection-compression molding process,the deformation of the products can be significantly reduced,and high-performance molding of ultra-thick-walled
14、 optical products can be realized.KEY WORDS:multilayer injection molding;ultra-thick-walled products;injection-compression;shrinkage deformation;mold design 非 结晶 性 透 明 聚合 物 如 聚 甲基 丙 烯 酸 甲酯(PMMA)、聚碳酸酯(PC)、环烯烃聚合物/环烯烃共聚物(COP/COC)等,具有优异的光学性能和力学性能,可替代传统无机玻璃1-3。近年来,随着高端制造业的发展,对聚合物光学产品的厚度提出了更高的要求。注射、注射-压缩工
15、艺具有可成形复杂形面和结构、批量生产效率高、无须二次加工等优势,是聚合物光学产品的主要成形方法。由于聚合物固有的收缩特性,常规注射工艺成形的厚度一般在6 mm 以下4-5。较大的厚度会使冷却过程中产品沿厚度方向的表面温度与熔体内部的芯层温度有较大差异。当塑件芯层温度高、冷却速度慢、收缩大以及表层冷却速度快时,会产生收缩不均的现象,甚至产生真空气泡等缺陷6-8。同时,冷却不均以及诸多收缩缺陷会产生较大的残余应力,对厚壁产品的尺寸精度产生影响9-10。超厚光学产品的高性能成形仍然是一个挑战。为了解决传统注射成形工艺无法成形超厚产品的难题,研究者们提出了多次注射成形工艺。不同于传统单次注射,多次注射
16、通过连续的几次注射成形出最终产品11-12。收缩形变和双折射是厚壁光学产品的主要缺陷,尺寸精度和光学性能也是评价光学产品的主要指标13-15。基于此,国内外学者针对多次注射成形对产品性能的影响展开了一些研究。Hopmann 等16-17设计了多层注射模具,研究了模具温度对 PMMA 和 PC 产品结合强度及光学质量的影响,研究表明,该工艺的收缩趋势较小,可以提高产品的成形精度和光学性能。Wang 等18研究了多次注射成形中镶件对蓝光物镜收缩率的影响,并与单次注射成形进行了比较。Nian 等19探讨了传统注射成形、两层注射成形和三层注射成形对大厚度凸透镜表面轮廓精度、循环时间和透光率的影响。结果表明,采用三层注射技术可显著减小表面轮廓误差和改善收缩分布情况。Liu 等20提出了一种多层反压注射工艺,并设计了相应的模具,研究了分层方式、反压对厚壁光学透镜收缩率、透光率和折射率的影响。曹磊等21-22使用 PMMA 为原材料,制作了光学厚壁制件三棱镜,利用模拟和实验的方法分析了分层注射对光学厚壁透镜产品尺寸稳定性的影响规律。结果表明,层厚分布对注射效果的影响最大,通过分层注射,可以减小光学厚