精密连接技术及其在-航空航天工业中的应用.ppt

精密连接技术及其在航空航天工业中的应用Precision Joining Technique and itsPrecision Joining Technique and itsApplication in Aerospace IndustryApplication in Aerospace IndustryShanghai Jiao Tong UniversityShanghai Jiao Tong UniversityMaterials Science and Engineering CollegeMaterials Science and Engineering CollegeSJTU Welding Engineering InstituteSJTU Welding Engineering Institute1 1Contents IntroductionIntroduction Conventional welding techniqueConventional welding technique Precision joining techniquePrecision joining technique Difference between precision joining and Difference between precision joining and conventional welding techniqueconventional welding technique Main application areas of precision joining Main application areas of precision joining techniquetechnique Some frequently used techniques for precision Some frequently used techniques for precision joiningjoining Material in aerospace and their joining featuresMaterial in aerospace and their joining features Application of precision joining technique in Application of precision joining technique in aerospaceaerospace Application examples:Electronic Beam Brazing for Application examples:Electronic Beam Brazing for parts parts in aerospacein aerospace Application examples:Laser welding for parts in Application examples:Laser welding for parts in aerospaceaerospace Conclusion and prospectConclusion and prospect2 2IntroductionIntroduction The joining technique The joining technique is an indispensable processing means in is an indispensable processing means in modern manufacturing.It uses the mechanical,chemical modern manufacturing.It uses the mechanical,chemical methods,such as partial heating or with pressure,to join the two methods,such as partial heating or with pressure,to join the two parts or materials.Commonly there are non-permanent and parts or materials.Commonly there are non-permanent and permanent joint:permanent joint:Non-permanent joint:Non-permanent joint:the joint part can be moved or dis-the joint part can be moved or dis-assembledassembled，e.g.hinge joint,chain joint,screw joint,etc.e.g.hinge joint,chain joint,screw joint,etc.Permanent joint:Permanent joint:the joint can not be moved or disassembled the joint can not be moved or disassembled except destruction,e.g.glue joint,rivet jointexcept destruction,e.g.glue joint,rivet joint、all kinds of all kinds of welding joints,etc.(Here only the welding joints and their welding joints,etc.(Here only the welding joints and their welding technique will be discussed.)welding technique will be discussed.)Welding technique Welding technique generally uses some kind of heat source to generally uses some kind of heat source to partially heat material(especially metal)under the certain partially heat material(especially metal)under the certain protective condition,sometimes with certain pressure,to form a protective condition,sometimes with certain pressure,to form a permanent welding joint,which means the atomic or molecular permanent welding joint,which means the atomic or molecular connection between the two materials or parts.connection between the two materials or parts.3 3IntroductionIntroduction Welding techniques are increasingly applied in manufacturing of Welding techniques are increasingly applied in manufacturing of products that consist of different parts with different materials,shapes,products that consist of different parts with different materials,shapes,structures and functions,to form a complex entire body.Thus the structures and functions,to form a complex entire body.Thus the working procedure of the entired workpiece can be greatly simplified,working procedure of the entired workpiece can be greatly simplified,the material can be saved and the production efficiency can be the material can be saved and the production efficiency can be increased.increased.The seeking for high quality and low cost of product is the important The seeking for high quality and low cost of product is the important strategy to get victory in the market competition for most enterprises strategy to get victory in the market competition for most enterprises today.And the high quality of product is generally guaranteed by today.And the high quality of product is generally guaranteed by reasonable product design,reasonable product design,reliable processing precisionreliable processing precision,and effective,and effective inspection method.inspection method.As an important processing means in manufacturing of modern As an important processing means in manufacturing of modern product,the joining technique and its precision increasingly get product,the joining technique and its precision increasingly get extensive attention.With development of technology,the precision extensive attention.With development of technology,the precision joining is becoming an effective way to reduce followed working joining is becoming an effective way to reduce followed working procedures,to decrease cost,and to improve quality.procedures,to decrease cost,and to improve quality.In some important areas(such as micro-electronics,aerospace etc.)In some important areas(such as micro-electronics,aerospace etc.)，the precision joining of some micro-structures become a critical the precision joining of some micro-structures become a critical technique for successful manufacturing,thus the precision and relibility technique for successful manufacturing,thus the precision and relibility of joint become the most important quality control point of product.of joint become the most important quality control point of product.4 4Conventional welding techniqueConventional welding technique The conventional welding technique,such as SMAW,SAW,The conventional welding technique,such as SMAW,SAW,GMAW,GTAW,etc.are widely used in manufacturing and GMAW,GTAW,etc.are widely used in manufacturing and enjoy the main popularity because of their low cost and enjoy the main popularity because of their low cost and simple operation.But for welding of some special materials simple operation.But for welding of some special materials or special structures,especially some micro-structures,their or special structures,especially some micro-structures,their application would be restrained due to some shortcomings,application would be restrained due to some shortcomings,such as:such as:Low energy density;Low energy density;Low welding speed and efficiency;Low welding speed and efficiency;Low controllable precision of welding parameters;Low controllable precision of welding parameters;Low depth/width ratio of welding pool,for thick workpiece Low depth/width ratio of welding pool,for thick workpiece the multi-pass welding is necessary;the multi-pass welding is necessary;Wide HAZ and low performance of welding joint;Wide HAZ and low performance of welding joint;Big distortion of workpieceBig distortion of workpiece，correction measures are correction measures are needed;needed;Low precision of joint,mechanical post-processing would Low precision of joint,mechanical post-processing would be necessary for some important workpiece,etc.be necessary for some important workpiece,etc.5 5Precision joining techniquePrecision joining technique Precision joining technique Precision joining technique will use the proper joining method and will use the proper joining method and control technique according to the joint object,and control the joining control technique according to the joint object,and control the joining process precisely,so as to obtain the anticipated joint performance and process precisely,so as to obtain the anticipated joint performance and precision.precision.According to the size of joint object,the precision joining technique According to the size of joint object,the precision joining technique especially for packaging or assembling of IC components in micro-especially for packaging or assembling of IC components in micro-electronic area is called electronic area is called Micro-joining technique.Micro-joining technique.The main purpose of The main purpose of the common precision joiningthe common precision joining is to obtain the high is to obtain the high joint precision beside the reliable joint strength.During the joint precision beside the reliable joint strength.During the manufacturing of hot-working products,the shape,size and distortion manufacturing of hot-working products,the shape,size and distortion of jointed components would be precisely calculated and strictly of jointed components would be precisely calculated and strictly controlled,so the mechanical processing or other treatments are controlled,so the mechanical processing or other treatments are generally not necessary.generally not necessary.The main purpose of The main purpose of the micro-joiningthe micro-joining in micro-electronic area is to in micro-electronic area is to obtain the high conductivity and high reliability.So the joining methods obtain the high conductivity and high reliability.So the joining methods are somewhat different from common joining methods.Some factors are somewhat different from common joining methods.Some factors that are neglected in common joining would be very sensitive under the that are neglected in common joining would be very sensitive under the condition of micro-joining,and even be the main influence factor for condition of micro-joining,and even be the main influence factor for joint quality.joint quality.6 6Difference between precision joining and Difference between precision joining and conventional welding techniqueconventional welding techniquePrecision joiningPrecision joiningConventional weldingConventional weldingWorking precision of joint Working precision of joint HighHighLowLowRequirement of joint cleaningRequirement of joint cleaningHighHighLowLowGeometrical size of jointGeometrical size of jointBig,small,minuteBig,small,minuteBigBigOutput power of heat sourceOutput power of heat sourceHigh,lowHigh,lowHighHighPower density of heat sourcePower density of heat sourceHigh,lowHigh,lowLowLowControl precision of powerControl precision of powerHighHighLowLowAutomation degree of joiningAutomation degree of joiningHighHighLowLowRequirement of quality inspectRequirement of quality inspectHighHighLowLowRequired main performance Required main performance of jointof jointConductivity,Conductivity,sealabilitysealabilityMechanical perf.,Mechanical perf.,anticorrosionanticorrosion7 7Main application areas of precision joining techniqueMain application areas of precision joining technique Micro-electronics:Micro-electronics:IC-packagingIC-packagingmicro-joiningmicro-joining Aerospace:Aerospace:Joining of different special materials,Joining of different special materials,manufacturing of navigation device,manufacturing of navigation device,detection detection radar and other precision radar and other precision ponents.Precise machine:Precise machine:Manufacturing of variety of NC-Manufacturing of variety of NC-machine,machine,robot,laser system,medical device,robot,laser system,medical device,press system,press system,spinning,printing and dyeing device,spinning,printing and dyeing device,semi-semi-conductor processing system,etc.conductor processing system,etc.IT-Industry:IT-Industry:Manufacturing of variety of Manufacturing of variety of communication communication device,computer,digital products,device,computer,digital products,instrument,instrument,sensors,etc.sensors,etc.Automobile:Automobile:Precise assembly joining for variety of Precise assembly joining for variety of engine engine components and automobile components and automobile bodywork,etc.bodywork,etc.8 8Some frequently used techniques Some frequently used techniques for precision joiningfor precision joiningPreciseJoiningTech.Micro-joiningCommon PreciseJoiningFusionWeldingGMAWPAWLaser assisted A.W.Laser WeldingEBWResistance WeldingSoldering&BrazingBrazingSolderingPressure WeldingSolid-phaseWeldingDiffusion WeldingMicro-Resistance W.Fusion WeldingLow Power Laser W.SolderingVapor Reflow S.Wave SolderingInfrared Reflow S.Laser Reflow S.Ultrasonic Pressure W.Solid-phaseWeldingDiffusion WeldingHot Pressure WeldingU.Hot Pressure W.9 9Diffusion weldingDiffusion weldingJoining Principle:Joining Principle:Under certain pressure,the material surfaces contact each other,and Under certain pressure,the material surfaces contact each other,and the partial plastic deformation occurs to destroy the oxidation film,and the partial plastic deformation occurs to destroy the oxidation film,and then some minute joining points are formed.With time going,the tightly then some minute joining points are formed.With time going,the tightly jointed surfaces will gradually growth because of creep deformation and jointed surfaces will gradually growth because of creep deformation and diffusion,the interspaces will decrease and the jointed surfaces diffusion,the interspaces will decrease and the jointed surfaces increase.Finally the interspaces totally disappear and a joint will be increase.Finally the interspaces totally disappear and a joint will be formed.formed.Main mechanism of joining:deformation and diffusionMain mechanism of joining:deformation and diffusionTimeburnishingcleaningMaterial BMaterial Aheatingvacuum pumppolishinginspectionpressure1010Diffusion weldingDiffusion weldingInfluence factors:Influence factors:Surface filmSurface film(organic contamination,surface oxide and their(organic contamination,surface oxide and their properties,etc.)properties,etc.)Surface roughnessSurface roughness Technologic factorsTechnologic factors(temperature,pressure,time,etc.)(temperature,pressure,time,etc.)Application featuresApplication features The preparation of material joining surface is strict.The preparation of material joining surface is strict.A certain pressure is needed,but should not result in A certain pressure is needed,but should not result in macromacro-scopical plastic deformation.scopical plastic deformation.It has high welding precision,but long time and low efficiency.It has high welding precision,but long time and low efficiency.It can weld the workpiece with complex shape,It can weld the workpiece with complex shape,cavity or cavity or overlap,without limit of plate thicknessoverlap,without limit of plate thickness It can weld different metals.It can weld different metals.1111Diffusion weldingDiffusion weldingApplication examplesApplication examplesDiffusion Welding of copper and titaniumDW of impellerDW of stainless steel and copperDW of stainless steel and ceramic1212Hot pressure welding and ultrasonic Hot pressure welding and ultrasonic hot pressure weldinghot pressure welding Joining PrincipleJoining PrincipleHot pressureHot pressure results in typical plastic deformation and mutual results in typical plastic deformation and mutual diffusion in the joint zonediffusion in the joint zone；Ultrasonic vibration Ultrasonic vibration cause friction between cause friction between the metal joint surfacesthe metal join