激光焊接原理及实践应用

WJMTechnologiesExcellenceInMaterialJoining激光焊接LasersWeldingGirishP.Kelkar,Ph.D.WJMTechnologiesExcellenceInMaterialJoining激光LASER受激辐射式光频放大器的英文第一个字母的缩写LightAmplificationbyStimulationofEmittedRadiationWJMTechnologiesExcellenceInMaterialJoining参考资料References激光的工业应用-J.F.ReadyIndustrialApplicationsofLasers,J.F.Ready激光焊接，W.W.DuleyLaserWelding,W.W.Duley激光加工，W.M.SteenLaserMaterialsProcessing,W.M.SteenAWS焊接手册，1-4AWSWeldingHandbooks,1-4激光加工手册-美国激光协会出版HandbookofLaserMaterialsProcessingPublishedbytheLaserInstituteofAmerica公开的相关文献PublishedliteratureWJMTechnologiesExcellenceInMaterialJoining请记住…..Remember…..学习需要积极的参与Learningrequiresactiveparticipation不耻下问Feelfreetoaskquestions无所顾及地提出个人不同见解DonothesitatetopresentdifferentviewpointsWJMTechnologiesExcellenceInMaterialJoining光Light光是一种电磁辐射Lightiselectro-magneticradiation我们听不到.Wavesthatyoucannothear可见光的波长在0.4-0.7微米之间。Visiblefrom0.4-0.7micronwavelength波长小于0.4微米是紫外线和X光Below0.4–ultraviolettox-rays波长大于700nm的光为红外线和微波。Above0.7–infra-redtomicrowaves0.40.7µmµmVisibleGammax-rayUVIRMicrowaveTVRadio0.01µm0.001µmYAG1µmWJMTechnologiesExcellenceInMaterialJoining光的吸收和颜色AbsorptionandColor物体的颜色来源于它反射的光的波长Colorofanobject(wavelengththatitreflects)颜色和光的波长是相关联的。Colorisassociatedwithparticularwavelength黑色和白色代表着什么？Whatisthemeaningofblackorwhitecolor?黑色表面吸收了YAG光，而白色在反射了大部分光。BlacksurfacewillabsorbYAGlightwhilewhitewillreflectmostofitWJMTechnologiesExcellenceInMaterialJoining我们为什么需要激光？WhydoweneedLasers?材料加工需要吸收很强的光。Absorptionformaterialsprocessingrequiresveryintenselight高强度的光可以通过激光聚焦成光束获得。Intensitycanbegeneratedbyfocusingabeamoflaserlight普通光不能聚焦成很高的能量密度（或足够小的点）Ordinarylightdoesnotfocusdowntoahighenoughpowerdensity(orsmallenoughspotsize)手持放大镜可以把太阳光聚焦让纸燃烧但是不能把金属融化Hand-heldlenscanfocussunlighttosetfiretopaperbutnotenoughtomeltmetalWJMTechnologiesExcellenceInMaterialJoiningLightandLasers单频的（单波长）Monochromatic(singlewavelength)校准的（平行光）Collimated(parallel)激光LaserLight普通光OrdinaryLight很多波长Manywavelengths不平行NotparallelWJMTechnologiesExcellenceInMaterialJoiningLightandLasers激光LaserLight普通光OrdinaryLightWJMTechnologiesExcellenceInMaterialJoining激光的聚焦FocusingofLasers激光LaserLight普通光OrdinaryLight单频（单波长）和校准（平行）的光可以聚焦成很小的焦点Monochromatic(singlewavelength)andCollimated(parallel)lightcanbefocusedtoaverysmallspotWJMTechnologiesExcellenceInMaterialJoining激光的种类TypesofLasers激光能量传输LaserPowerDelivery连续波ContinuousWave(CW)脉冲PulsedQ-开关Q-switched激光频率LaserFrequencies基频和倍频FundamentalandmultiplesWJMTechnologiesExcellenceInMaterialJoining连续光纤激光ContinuousWaveFiberLasers激光在光纤中产生Laserlightiscreatedinthefiber可在连续波和脉冲波中使用CanbeusedinpulsedmodeaswellasCW可以被用于焊接和切割Canbeusedforweldingandcutting激光二极管光LaserDiodeLight激光二极管光LaserDiodeLight光纤FiberWJMTechnologiesExcellenceInMaterialJoining脉冲YAG激光（焊接）PulsedYAGLasers(Welding)闪光灯开关产生脉冲Flashlampturnsonandofftocreatepulses光纤用于传送激光Fiberisusedtotransmitlaserlight闪光灯（光泵）FlashLamp(OpticalPump)全反镜100%mirror90%反镜90%mirror光纤Fiber激光棒LaserRodWJMTechnologiesExcellenceInMaterialJoining脉冲打标激光PulsedMarkingLasersQ-switchingproducesveryshortpulses,10-100nano-secCannotbeusedforweldingLaserlightdelivereddirectly;nofiberFrequencycanbedoubledortripledtogetgreenorUVlightMMRodMirrorsQ-switchGalvoMirrorsFocusLensFrequencyMultiplier(notpresentinallmarkers)WJMTechnologiesExcellenceInMaterialJoiningGalvo-光学器件Galvo-Optics经常用于打标。Oftenusedformarkingapplications逐渐受到焊接应用的青睐。IsgainingpopularityforweldingapplicationsNutfield,Inc.LaserWJMTechnologiesWJMTechnologiesExcellenceInMaterialJoining激光频率LaserFrequencies上表只包括了大部分常用的和商业化的激光器。Tableincludesonlythemostcommonandcommercializedlasers。波长WavelengthRange激光种类Laser频率Frequencies(mm)远红外FarIRCO210.64近红外NearIRNd:YAG1.064可见光VisibleFrequencydoubledYAGCopper-VaporLasers0.5320.510紫外光UVFrequencytripledYAGFrequencyquadrupledYAGExcimer0.3540.2660.15-0.35WJMTechnologiesExcellenceInMaterialJoining脉冲YAG激光焊接典型示意图TypicalLayoutforPulsedYAGWeldingLasers镀膜反光镜CoatedMirrors激光Laser光纤OpticalFiber聚光头FocusHead工件Workpiece透镜Lens注：某些激光不通过光纤直接传输。Note:SomelasersaredelivereddirectwithoutfiberWJMTechnologiesExcellenceInMaterialJoining聚焦高度和焦点尺寸Focusheightandspotsize短焦距透镜将光束聚焦成更小的点。Shortfocallengthlens(ofgivendiameter)willfocusthebeamtoasmallerspot高的能量密度。HigherenergydensityFocusheightiscriticalduetoshallowdepthoffocusLensprotectionfromworkpiecespatterisimportant短焦距ShortFocalLength长焦距LongFocalLengthDepthofFocusSpotSizeWJMTechnologiesExcellenceInMaterialJoiningTimeShareAsinglelasercanbeusedformultipleapplicationsonatimesharedbasis基于同一个理论,单雷射可以一次性用于多种应用.Mostconvenientwithtransmissionthroughopticalfiber通过可见纤维的转换是最方便的.Processingstationscanbeindifferentrooms工作台可以放在不同的房间.Mirrors(100%Reflective)全反镜WJMTechnologiesExcellenceInMaterialJoiningEnergyShareLaserenergysplitintomultiplefragments雷射能量分成多个部分Typicallythreeoutputsforcircumferentialspotwelding典型的是圆周点焊接的3份输出量Mirrors(PartiallyReflective)反光镜(部分反光)33%50%100%30W10W10W10WWJMTechnologiesExcellenceInMaterialJoiningTotalInternalReflection完全内反射Lightpropagationthroughfibersdependsontotalinternalreflection通过光纤的光线传播完全取决于完全内反射Air空气Gla