精密热压成型机关键技术研究与实现
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摘要
随着光学电子设备在航天航空、仪器仪表和消费电子等领域的广泛应用,其显示屏及装饰面板的设计形式多样,且3D曲面玻璃更是一种潮流。因此,热压成型就成为量大面广的曲面玻璃制造的核心技术。针对精密成型设备的温度分布与控制及其压力控制等问题,开展精密热压成型关键技术研究,建立多工位成型工艺的仿真模型和加热板传热模型,模拟了玻璃在成型过程中温度变化历程以及加热板表面的温度分布,优化设计出一种新型蛇管式加热管;并研制了精密温控系统和精密压力控制系统,测试结果表明,该温控系统精度在±2℃以内,压力控制响应精度为0.001 MPa,能满足热压成型的要求。开发了多工位精密热压成型样机,建立一套可靠的工艺流程,并利用该样机开展了曲面玻璃的热压工艺试验研究。试验结果表明:压型温度为800℃,压力为0.6 MPa时,可实现成型玻璃轮廓度<0.010 mm,表面粗糙度Ra<0.02μm,良品率达90%以上。
As optical electronic equipment is widely applied in the field of aerospace, instruments and meters and consumer electronics, etc, there are various design forms of the display screen and decoration panel of the optical electronic devices. Meanwhile,3 D curved shape surface has become a trend. Therefore, compression molding has become one of the most important technologies in the curved glass manufacturing. The critical technology of the compression molding is studied about temperature distribution and the control of temperature and pressure. The simulation model of multi-station molding process is established to simulate the temperature history of glass during the molding process. The heat transfer model of heating plate is built to simulate the temperature distribution of the surface of the heating plate. And a new type of snake heating tube has been optimally designed. The precision temperature control system and precision pressure control system are developed. The results of tests show that the temperature control precision is within ±2 ℃ and the accuracy of pressure control can reach 0.001 MPa, both of which can meet the requirements of compression molding. Finally a precision multi-station compression molding tool is developed, and the reliable compression molding technological process is established, which sets the foundation for experimental research of compression molding. The experimental results show that the profile tolerance of glass less than 0.01 mm, the surface roughness Ra less than 0.02 μm,and the yield above 90% can be realized by the developed multi-station compression molding tool under the molding temperature of 800 ℃ and the molding pressure of 0.8 MPa.
As optical electronic equipment is widely applied in the field of aerospace, instruments and meters and consumer electronics, etc, there are various design forms of the display screen and decoration panel of the optical electronic devices. Meanwhile,3 D curved shape surface has become a trend. Therefore, compression molding has become one of the most important technologies in the curved glass manufacturing. The critical technology of the compression molding is studied about temperature distribution and the control of temperature and pressure. The simulation model of multi-station molding process is established to simulate the temperature history of glass during the molding process. The heat transfer model of heating plate is built to simulate the temperature distribution of the surface of the heating plate. And a new type of snake heating tube has been optimally designed. The precision temperature control system and precision pressure control system are developed. The results of tests show that the temperature control precision is within ±2 ℃ and the accuracy of pressure control can reach 0.001 MPa, both of which can meet the requirements of compression molding. Finally a precision multi-station compression molding tool is developed, and the reliable compression molding technological process is established, which sets the foundation for experimental research of compression molding. The experimental results show that the profile tolerance of glass less than 0.01 mm, the surface roughness Ra less than 0.02 μm,and the yield above 90% can be realized by the developed multi-station compression molding tool under the molding temperature of 800 ℃ and the molding pressure of 0.8 MPa.
引文
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[12]何国良.光学玻璃精密模压成型设备机构设计[D].深圳:深圳大学,2017.HE Guoliang.Structure design of optical glass precision molding equipment[D].Shenzhen:Shenzhen University,2017.
[13]WACHTEL P,MOSADDEGH P,CLEASON B.Performance evaluation of a bench-top precision glass molding machine[J].Advances in Mechanical Engineering,2013,2013(2013):761-776.
[14]BALAJEE A,PAUL F.J,DHANANJAY J,et al.Final shape of precision molded optics:Part II-Validation and sensitivity to material properties and process parameters[J].Journal of Thermal Stresses,2012,35(4-6):614-636.
[15]ZHOU Jian,LI Mujun,SHEN Lianguan.FEM analysis of glass lens molding press[J].Advanced Materials Research,2013,654(5):1961-1965.
[16]SHACKELFORD J F,DOREMUS R H.Ceramic and glass materials:Structure,properties and processing[M].New York:Springer,2008.
[17]杨世铭,陶文铨.传热学[M].北京:高等教育出版社,2011.YANG Shiming,TAO Wenquan.Heat transfer[M].Beijing:Higher Education Press,2011.
[18]MANSOUR S E,KEMBER G C,DUBAY R.Online optimization of fuzzy-PID control of a thermal process[J].ISA Transactions,2005,44(10):305-314.
[2]周剑.精密玻璃透镜热压成型技术中的关键问题研究[D].合肥:中国科学技术大学,2015.ZHOU Jian.Study on several major issues in precision glass compression molding[D].Hefei:University of Science and Technology of China,2015.
[3]JAIN A,YI A Y.Numerical modeling of viscoelastic stress relaxation during glass lens forming process[J].Journal of the American Ceramic Society,2005,88(3):530-535.
[4]JAIN A,YI A Y.Finite element modeling of structural relaxation during annealing of a precision-molded glass lens[J].Journal of Manufacturing Science and Engineering,2006,128(3):683-690.
[5]SU Lijuan,CHEN Yang,YI A Y.Refractive index variation in compression molding of precision glass optical components[J].Applied Optics,2008,47(10):1662-1667.
[6]SU Lijuan,YI A Y.Investigation of the effect of coefficient of thermal expansion on prediction of refractive index of thermally formed glass lenses using FEM simulation[J].Journal of Non-Crystalline Solids,2011,375(15):3006-3012.
[7]ZHOU Jian,LI Mujun,HU Yang.Numerical evaluation on the curve deviation of the molded glass lens[J].Journal of Manufacturing Science and Engineering,2014,136(5):051004.
[8]BALAJEE A,PAUL F J,DHANANJAY J,et al.Final shape of precision molded optics:Part I-computational approach,material definitions and the effect of lens shape[J].Journal of Thermal Stresses,2012,35(4-6):550-578.
[9]朱科军.光学玻璃透镜模压成型的数值仿真和实验研究[D].长沙:湖南大学,2013.ZHU Kejun.Experimental study and numerical simulation of glass molding process for optical glass lens[D].Changsha:Hunan University,2013.
[10]季月良,沈连婠,李木军.精密玻璃透镜小型热压成型炉支承系统优化设计[J].新技术新工艺,2015,1(6):19-21.JI Yueliang,SHEN Lianguan,LI Mujun.Optimization design of bracing system of small precision glass lens molding pressing furnace[J].New Technology&New Process,2015,1(6):19-21.
[11]王小权.光学玻璃精密模压设备总体设计及加热系统研制[D].深圳:深圳大学,2017.WANG Xiaoquan.Overall design and heating system development of optical glass precision molding equipment[D].Shenzhen:Shenzhen University,2017.
[12]何国良.光学玻璃精密模压成型设备机构设计[D].深圳:深圳大学,2017.HE Guoliang.Structure design of optical glass precision molding equipment[D].Shenzhen:Shenzhen University,2017.
[13]WACHTEL P,MOSADDEGH P,CLEASON B.Performance evaluation of a bench-top precision glass molding machine[J].Advances in Mechanical Engineering,2013,2013(2013):761-776.
[14]BALAJEE A,PAUL F.J,DHANANJAY J,et al.Final shape of precision molded optics:Part II-Validation and sensitivity to material properties and process parameters[J].Journal of Thermal Stresses,2012,35(4-6):614-636.
[15]ZHOU Jian,LI Mujun,SHEN Lianguan.FEM analysis of glass lens molding press[J].Advanced Materials Research,2013,654(5):1961-1965.
[16]SHACKELFORD J F,DOREMUS R H.Ceramic and glass materials:Structure,properties and processing[M].New York:Springer,2008.
[17]杨世铭,陶文铨.传热学[M].北京:高等教育出版社,2011.YANG Shiming,TAO Wenquan.Heat transfer[M].Beijing:Higher Education Press,2011.
[18]MANSOUR S E,KEMBER G C,DUBAY R.Online optimization of fuzzy-PID control of a thermal process[J].ISA Transactions,2005,44(10):305-314.