塑料微流控芯片超声波键合机理的仿真与实验研究
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摘要
将超声波塑料焊接技术引入微流控芯片的封装具有不引入外部介质、键合强度高、键合时间短、材料适用范围广的优势。但就超声波塑料焊接技术而言,人们对其机理的理解还不十分深入。研究超声波塑料焊接的机理,可以更清楚的理解微流控芯片超声波键合时材料的熔融行为和焊接参数对键合过程的影响,为实现高质量键合服务。因此本文就超声波塑料焊接的机理做了部分基础性研究工作。首先针对聚合物材料,提出了一种粘弹性力学模型,该模型以广义Maxwell模型为基础,借助Boltzmann叠加原理和“时-温等效性原理”,可以将聚合物的动态模量表示为温度和频率的函数。然而在利用“时-温等效性原理”将松弛曲线片段平移为松弛主曲线时存在平移不准确的问题,因此文中对“时-温平移方程”进行了修正。推导了周期应变载荷下的粘弹性产热方程,从中得出,粘弹性热是在一定的温度范围内很短的时间里产生的,且低温段的粘弹性产热并不明显。对承受静压力和高频振动载荷的带矩形导能筋的有限元模型进行了动力学仿真,结果显示角点处的瞬时摩擦应力和相对滑动速度可以达到很高的数值,从而提出低温段超声波塑料焊接的热源来自界面上的摩擦热的观点。分别对摩擦热和粘弹性热提出了相应的仿真策略,结果表明超声波焊接接头上的温度场为非均匀温度场,粘弹性热使材料内的温度在很短的时间内攀升到很高的温度。用热电偶温度传感器进行了超声波塑料焊接接头温度场的实际测量,所得结果与仿真结果具有类似的趋势。对不同焊接压力和振幅作用下的模型温度场进行了仿真,结果显示温升速率随焊接压力和振幅的提高而提高,且振幅的影响要大于焊接压力的影响。最后,针对塑料微流控芯片的封装给出了两种不同的导能筋形式,从机理方面分析了其可行性,并对该两种形式导能筋的芯片进行了超声波键合实验。
It's a modern thing that introduces ultrasonic plastic welding technology to the field of microfluidic chip encapsulation,which has some advantages,such as external substance free, higher bonding strength,shorter bonding time,wider applying material,etc.To the ultrasonic plastic welding technology,however,the joining mechanism is not well understood.Research on the mechanism helps understand the melting behavior and the effects of welding parameter on the welding process,which would greatly benefit welding quality improvement.Aiming at providing theories to the advanced implication of the technology,the dissertation focuses on researching the joining mechanism of ultrasonic plastic welding.
Firstly,a practical viscoelastic model to the polymer material is proposed.Based on generalized Maxwell model and Boltzmann superposition principle and TTEP (Time-Temperature Equal Principle),the dynamic modulus could be expressed as the function of temperature and frequency.However,when shifting relaxation modulus segments of PMMA(polymethyl methacrylate) to gain a master curve,inaccuracy appears,so the normal Time-Temperature Shifting Factors is modified in the dissertation.The viscoelastic thermogenesis equation of viscoelastic material under periodical strain load is deduced.From the numerical solution it could be concluded that,viscoelastic heat is generated in a very short time in specified temperature range,and viscoelastic heat is not apparent at low temperature. Other heat generating mechanism may exist at temperature below T_g.Subsequently,kinetic simulation was proceeded to the Finite Element Model with a rectangular energy director, which bears both welding pressure and high-frequency vibrating loads.In the simulation, corner of the energy director produces high instantaneous friction stress and relative sliding velocity.So viewpoint was derived that the heat generating mechanism at low temperature is friction heat right at the interface.Simulating strategy to the friction heat and viscoelastic heat was put forward.The results showed that temperature field on the rectangular energy director is nonuniform,and viscoelastic heat makes the temperature rises in a very short time.To validate the proposed heat generating mechanism and the simulating method,experiments were proceeded with measurements of temperature tendency of energy director during welding process.Simulation of the temperature field when the welding parameters,that is welding pressure and amplitude,varies is proceeded,indicating that temperature rise rate tends to increase with the applied welding pressure and amplitude.At last,two kinds of energy director shape,triangular and rectangular,for the encapsulation of microfluidic chips is presented,and their feasibility is discussed theoretically.Encapsulating experiments of the two kinds of microfluidic chips were proceeded.
It's a modern thing that introduces ultrasonic plastic welding technology to the field of microfluidic chip encapsulation,which has some advantages,such as external substance free, higher bonding strength,shorter bonding time,wider applying material,etc.To the ultrasonic plastic welding technology,however,the joining mechanism is not well understood.Research on the mechanism helps understand the melting behavior and the effects of welding parameter on the welding process,which would greatly benefit welding quality improvement.Aiming at providing theories to the advanced implication of the technology,the dissertation focuses on researching the joining mechanism of ultrasonic plastic welding.
Firstly,a practical viscoelastic model to the polymer material is proposed.Based on generalized Maxwell model and Boltzmann superposition principle and TTEP (Time-Temperature Equal Principle),the dynamic modulus could be expressed as the function of temperature and frequency.However,when shifting relaxation modulus segments of PMMA(polymethyl methacrylate) to gain a master curve,inaccuracy appears,so the normal Time-Temperature Shifting Factors is modified in the dissertation.The viscoelastic thermogenesis equation of viscoelastic material under periodical strain load is deduced.From the numerical solution it could be concluded that,viscoelastic heat is generated in a very short time in specified temperature range,and viscoelastic heat is not apparent at low temperature. Other heat generating mechanism may exist at temperature below T_g.Subsequently,kinetic simulation was proceeded to the Finite Element Model with a rectangular energy director, which bears both welding pressure and high-frequency vibrating loads.In the simulation, corner of the energy director produces high instantaneous friction stress and relative sliding velocity.So viewpoint was derived that the heat generating mechanism at low temperature is friction heat right at the interface.Simulating strategy to the friction heat and viscoelastic heat was put forward.The results showed that temperature field on the rectangular energy director is nonuniform,and viscoelastic heat makes the temperature rises in a very short time.To validate the proposed heat generating mechanism and the simulating method,experiments were proceeded with measurements of temperature tendency of energy director during welding process.Simulation of the temperature field when the welding parameters,that is welding pressure and amplitude,varies is proceeded,indicating that temperature rise rate tends to increase with the applied welding pressure and amplitude.At last,two kinds of energy director shape,triangular and rectangular,for the encapsulation of microfluidic chips is presented,and their feasibility is discussed theoretically.Encapsulating experiments of the two kinds of microfluidic chips were proceeded.
引文
[1]张放,邵华.微流控芯片在生物分析中的应用研究进展.职业与健康.2007.6.
[2]C.H.Ah,J.W.Choi,G.Beaucage,J.H.Nevin,J.B.Lee,A.Puntambekar,J.Y.Lee.Disposable Smart lab on a chip for point-of-care clinical Diagnostics.IEEE,2004:154-173.
[3]王晓东,刘冲,马骊群,罗怡,王立鼎.塑料微流控芯片的制作及其自动化.高技术通讯.2004.
[4]温敏,王晓东,刘冲,马骊群.光学精密工程.PMMA微流控芯片微通道热压成形与键合工艺研究.2004,12:272-276.
[5]H.Becker,C.Gartner.Polymer micro fabrication methods for microfluidic analytical applications.Electrophoresis,2000,21:12-26.
[6]J.Y.Cheng,C.W.Wei,K.H.Hsu,T.H.Young.Direct-write laser micromachining and universal surface modification of PMMA for device Development.Sensor Actuat B-Chem,2004,99:186-96.
[7]D.Maas,B.Büstgens,J.Fahrenberg,W.Keller,P.Ruther,W.K.Schomburg,D.Seidel.Fabrication of microcomponents using adhesive bonding techniques.Proceedings,IEEE ninth Annual International Workshop on Micro Electro Mechanical Systems(MEMS).1996:331-336.
[8]GLASGOW I K,BEEBE D J,WHITE V E.Design Rules for Polyimide Solvent Bonding.Sensors and materials,1999,11(5):269-278.
[9]Jie-Wei Chen,Jerry Zybko,James Clements.Diode Laser Bonding of Planar MEMS,MOEMS,& Microfluidic Devices.2005 MRS Spring Meeting.
[10]R.Truckenmuller,Y.Cheng,R.Ahrens,H.Bahrs,G.Fischer,J.Lehmann.Micro ultrasonic welding:joining of chemically inert polymer microparts for single material fluidic components and systems.
[11]Roman Truckenmuller,Ralf Ahrens,Yue Cheng,Gunther Fischer,Volker Saile.An ultrasonic welding based process for building up a new class of inert fluidic microsensors and -actuators from polymers.Sensors and Actuators.2006.
[12]YEW KHOY CHUAH,LIANG-HAN CHIEN,B.C.CHANG,SHIH-JUNG LIU.Effects of the Shape of the Energy Director on Far-Field Ultrasonic Welding of Thermopalstics.Poly.Eng.Sci.2000,40:157.
[13]Jiromaru Tsujino,Tetsugi Ueoka,Koichi Hasegawa,Yuki Fujita,Toshiyuki Shiraki.New methods of ultrasonic welding of metal and plastic materials.Ultrasonics.1996,34:177-185.
[14]Jiromaru Tsujino.Recent Developments of Ultrasonic Welding.IEEE ULTRASONICS SYMPOSIUM,1995:1051-1060.
[15]M.Hongoh,M.Yoshikuni,H.Miura,T.Ueoka,J.Tsujino.Configuration of a 20-mm-Diameter 150 kHz Ultrasonic Longitudinal Vibration System for Plastic Welding.2004 IEEE International Ultrasonics,Ferroelectrics,and Frequency Control Joint 50th Anniversary Conference,2004:2326-2329.
[16]David A.Grewell.AMPLITUDE AND FORCE PROFILING:STUDIES IN ULTRASONIC WELDING OF THERMOPLASTICS.Branson Ultrasonics Corporation.
[17]杨世勤,阎久春,田修波,王小峰,蔡七雄.超声波塑料焊接机的能量控制模式.焊接学报,1995,16(2):118-123.
[18]田修波,杨士勤,阎久春,董震.压力可变的超声波塑料焊机.电焊机.1999,29(12):.
[19]张宗波,罗恰,王晓东,王立鼎.塑料超声波焊接及其用于聚合物MEMS器件键合的研究进展.焊接.2008,8:9-15.
[20]杨士勤,董庆刚,田修波,王小峰,魏强.超声波焊接聚乙烯接头温度场的计算及检测.焊接学报,1995,16(13):172-178.
[21]赵学曾,侯旭光,侯国璋,宫伟,代礼周.超声波塑料焊接机工艺参数的研究.2001中国控制与决策学术年会论文集,1147-1150.
[22]G.Menges,H.Potente.Study on the Weldability of Thermoplastic Materials by Ultrasound.Welding in the world,1971,9(1/2):46-59.
[23]C.J.Aliosio,D.G.Wahl,E.E.Whetsel.A Simplified Thermoviscoelastic Analysis of Ultrasonic Bonding.SPE Technical Papers,1972:16-19.
[24]M.N.Tolunary,P.B.Dawson,K.K.Wang.Heat and Bonding Mechanisms in Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1983,23(13):726-733.
[25]Avraham Benatar.Timothy G.Ootowski.Ultrasonic Welding of PEEK Graphite APC-2Composites.Polymer Engineering and Science,1989,29(23):1705-1721.
[26]Avraham Benatar,Raman V.Eswaran,Satinder K.Nayar.Ultrasonic welding of thermoplastics in the near-field.Polymer Engineering and Science.1989,29(23):1689-1698.
[27]Avranham Benatar,Zhang Cheng.Ultrosonic Welding of Thermopalstics in the Far-Field.Polymer Engineering and Science.1989,29:1699.
[28]C.J.Nonhof,G.A.Luiten.Estimates for Process Conditions During the Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1996,36(9):1177-1183.
[29]E.J.Frankel,K.K.Wang.Energy Transfer and Bond Strength in Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1980,20(6):396-401.
[30]Xiaolin Wang,Jiuchun Yah,Ruiqi Li,Shiqin Yang.FEM Investigation of the Temperature Field of Energy Director During Ultrasonic Welding of PEEK Composites.Journal of Thermoplastic Composite Materials,2006,19(5):593-606.
[31]K.S.Suresh,M.Roopa Rani,K.Prakasan,R.Rudramoorthy.Modeling of temperature distribution in ultrasonic welding of thermoplastics for various joint designs.Journal of Materials Processing Technology,2007,186(1-3):138-146.
[32]梁延德,邓莹莹,刘利.超声波塑料焊接温度场的有限元计算及检测.机械工程师,2004:38-40.
[33]梁延德,刘川.超声波塑料焊接温度场的数值模拟.机械科学与技术,2003,22(增刊):180-182.
[34]韦鹤,王晓东,刘冲,廖俊峰.塑料微流控芯片的超声波焊接键合的仿真.中国机械工程,2005,16(增刊):82-85.
[35]武军,李和平.高分子物理及化学.北京:中国轻工业出版社.2001:106,190.
[36]J.F.Mano,J.C.Viana.Stress-strain experiments as a mechanical spectroscopic technique to characterize the glass transition dynamics in poly(ethylene terephthalate).Polymer Testing,2006,25(7):953-960.
[37]过梅丽,赵得禄.高分子物理.北京:北京航空航天大学出版社.2005:183,199,204.
[38]何曼君,张江东,陈维孝,董西侠.高分子物理(第三版).上海:复旦大学出版社.2007:113.
[39]Kunihiko Takeda,Hirokazu Tanaka,Toshiaki Tsuchiya,Seiji Kaneko.Molecular movement during welding for engineering plastics using Langevin transducer equipped with half-wave-length step horn.Ultrasonics,1998,36:75-78.
[40]周玉生,闫久春,卢彤,杨士勤.塑料超声波焊接过程及质量研究Ⅲ焊接接头质量影响因素分析.材料科学与工艺,1999,7(增刊):59-62.
[41]Wang Xiaolin,Li Ruiqi,Yan Jiuchun,Yang Shiqin.Transient finite element analysis of ultrasonic welding of PEEK.CHINA WELDING,2006,15(2):55-59.
[42]李晓莹.传感器与测试技术.北京:高等教育出版社,2004:218-221.
[43]刘川.超声波塑料焊接机理和工艺实验研究:(硕士学位论文).大连:大连理工大学,2003.
[2]C.H.Ah,J.W.Choi,G.Beaucage,J.H.Nevin,J.B.Lee,A.Puntambekar,J.Y.Lee.Disposable Smart lab on a chip for point-of-care clinical Diagnostics.IEEE,2004:154-173.
[3]王晓东,刘冲,马骊群,罗怡,王立鼎.塑料微流控芯片的制作及其自动化.高技术通讯.2004.
[4]温敏,王晓东,刘冲,马骊群.光学精密工程.PMMA微流控芯片微通道热压成形与键合工艺研究.2004,12:272-276.
[5]H.Becker,C.Gartner.Polymer micro fabrication methods for microfluidic analytical applications.Electrophoresis,2000,21:12-26.
[6]J.Y.Cheng,C.W.Wei,K.H.Hsu,T.H.Young.Direct-write laser micromachining and universal surface modification of PMMA for device Development.Sensor Actuat B-Chem,2004,99:186-96.
[7]D.Maas,B.Büstgens,J.Fahrenberg,W.Keller,P.Ruther,W.K.Schomburg,D.Seidel.Fabrication of microcomponents using adhesive bonding techniques.Proceedings,IEEE ninth Annual International Workshop on Micro Electro Mechanical Systems(MEMS).1996:331-336.
[8]GLASGOW I K,BEEBE D J,WHITE V E.Design Rules for Polyimide Solvent Bonding.Sensors and materials,1999,11(5):269-278.
[9]Jie-Wei Chen,Jerry Zybko,James Clements.Diode Laser Bonding of Planar MEMS,MOEMS,& Microfluidic Devices.2005 MRS Spring Meeting.
[10]R.Truckenmuller,Y.Cheng,R.Ahrens,H.Bahrs,G.Fischer,J.Lehmann.Micro ultrasonic welding:joining of chemically inert polymer microparts for single material fluidic components and systems.
[11]Roman Truckenmuller,Ralf Ahrens,Yue Cheng,Gunther Fischer,Volker Saile.An ultrasonic welding based process for building up a new class of inert fluidic microsensors and -actuators from polymers.Sensors and Actuators.2006.
[12]YEW KHOY CHUAH,LIANG-HAN CHIEN,B.C.CHANG,SHIH-JUNG LIU.Effects of the Shape of the Energy Director on Far-Field Ultrasonic Welding of Thermopalstics.Poly.Eng.Sci.2000,40:157.
[13]Jiromaru Tsujino,Tetsugi Ueoka,Koichi Hasegawa,Yuki Fujita,Toshiyuki Shiraki.New methods of ultrasonic welding of metal and plastic materials.Ultrasonics.1996,34:177-185.
[14]Jiromaru Tsujino.Recent Developments of Ultrasonic Welding.IEEE ULTRASONICS SYMPOSIUM,1995:1051-1060.
[15]M.Hongoh,M.Yoshikuni,H.Miura,T.Ueoka,J.Tsujino.Configuration of a 20-mm-Diameter 150 kHz Ultrasonic Longitudinal Vibration System for Plastic Welding.2004 IEEE International Ultrasonics,Ferroelectrics,and Frequency Control Joint 50th Anniversary Conference,2004:2326-2329.
[16]David A.Grewell.AMPLITUDE AND FORCE PROFILING:STUDIES IN ULTRASONIC WELDING OF THERMOPLASTICS.Branson Ultrasonics Corporation.
[17]杨世勤,阎久春,田修波,王小峰,蔡七雄.超声波塑料焊接机的能量控制模式.焊接学报,1995,16(2):118-123.
[18]田修波,杨士勤,阎久春,董震.压力可变的超声波塑料焊机.电焊机.1999,29(12):.
[19]张宗波,罗恰,王晓东,王立鼎.塑料超声波焊接及其用于聚合物MEMS器件键合的研究进展.焊接.2008,8:9-15.
[20]杨士勤,董庆刚,田修波,王小峰,魏强.超声波焊接聚乙烯接头温度场的计算及检测.焊接学报,1995,16(13):172-178.
[21]赵学曾,侯旭光,侯国璋,宫伟,代礼周.超声波塑料焊接机工艺参数的研究.2001中国控制与决策学术年会论文集,1147-1150.
[22]G.Menges,H.Potente.Study on the Weldability of Thermoplastic Materials by Ultrasound.Welding in the world,1971,9(1/2):46-59.
[23]C.J.Aliosio,D.G.Wahl,E.E.Whetsel.A Simplified Thermoviscoelastic Analysis of Ultrasonic Bonding.SPE Technical Papers,1972:16-19.
[24]M.N.Tolunary,P.B.Dawson,K.K.Wang.Heat and Bonding Mechanisms in Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1983,23(13):726-733.
[25]Avraham Benatar.Timothy G.Ootowski.Ultrasonic Welding of PEEK Graphite APC-2Composites.Polymer Engineering and Science,1989,29(23):1705-1721.
[26]Avraham Benatar,Raman V.Eswaran,Satinder K.Nayar.Ultrasonic welding of thermoplastics in the near-field.Polymer Engineering and Science.1989,29(23):1689-1698.
[27]Avranham Benatar,Zhang Cheng.Ultrosonic Welding of Thermopalstics in the Far-Field.Polymer Engineering and Science.1989,29:1699.
[28]C.J.Nonhof,G.A.Luiten.Estimates for Process Conditions During the Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1996,36(9):1177-1183.
[29]E.J.Frankel,K.K.Wang.Energy Transfer and Bond Strength in Ultrasonic Welding of Thermoplastics.Polymer Engineering and Science,1980,20(6):396-401.
[30]Xiaolin Wang,Jiuchun Yah,Ruiqi Li,Shiqin Yang.FEM Investigation of the Temperature Field of Energy Director During Ultrasonic Welding of PEEK Composites.Journal of Thermoplastic Composite Materials,2006,19(5):593-606.
[31]K.S.Suresh,M.Roopa Rani,K.Prakasan,R.Rudramoorthy.Modeling of temperature distribution in ultrasonic welding of thermoplastics for various joint designs.Journal of Materials Processing Technology,2007,186(1-3):138-146.
[32]梁延德,邓莹莹,刘利.超声波塑料焊接温度场的有限元计算及检测.机械工程师,2004:38-40.
[33]梁延德,刘川.超声波塑料焊接温度场的数值模拟.机械科学与技术,2003,22(增刊):180-182.
[34]韦鹤,王晓东,刘冲,廖俊峰.塑料微流控芯片的超声波焊接键合的仿真.中国机械工程,2005,16(增刊):82-85.
[35]武军,李和平.高分子物理及化学.北京:中国轻工业出版社.2001:106,190.
[36]J.F.Mano,J.C.Viana.Stress-strain experiments as a mechanical spectroscopic technique to characterize the glass transition dynamics in poly(ethylene terephthalate).Polymer Testing,2006,25(7):953-960.
[37]过梅丽,赵得禄.高分子物理.北京:北京航空航天大学出版社.2005:183,199,204.
[38]何曼君,张江东,陈维孝,董西侠.高分子物理(第三版).上海:复旦大学出版社.2007:113.
[39]Kunihiko Takeda,Hirokazu Tanaka,Toshiaki Tsuchiya,Seiji Kaneko.Molecular movement during welding for engineering plastics using Langevin transducer equipped with half-wave-length step horn.Ultrasonics,1998,36:75-78.
[40]周玉生,闫久春,卢彤,杨士勤.塑料超声波焊接过程及质量研究Ⅲ焊接接头质量影响因素分析.材料科学与工艺,1999,7(增刊):59-62.
[41]Wang Xiaolin,Li Ruiqi,Yan Jiuchun,Yang Shiqin.Transient finite element analysis of ultrasonic welding of PEEK.CHINA WELDING,2006,15(2):55-59.
[42]李晓莹.传感器与测试技术.北京:高等教育出版社,2004:218-221.
[43]刘川.超声波塑料焊接机理和工艺实验研究:(硕士学位论文).大连:大连理工大学,2003.