激光焊接原理及實踐應(yīng)用課件

激光焊接

LasersWelding

GirishP.Kelkar,Ph.D.激光焊接

LasersWelding

GirishP.激光LASER受激輻射式光頻放大器的英文第一個字母的縮寫LightAmplificationbyStimulationofEmittedRadiation2激光LASER受激輻射式光頻放大器的英文第一個字母的縮寫2參考資料References激光的工業(yè)應(yīng)用-J.F.ReadyIndustrialApplicationsofLasers,J.F.Ready激光焊接，W.W.DuleyLaserWelding,W.W.Duley激光加工，W.M.SteenLaserMaterialsProcessing,W.M.SteenAWS焊接手冊，1-4AWSWeldingHandbooks,1-4激光加工手冊-美國激光協(xié)會出版HandbookofLaserMaterialsProcessingPublishedbytheLaserInstituteofAmerica公開的相關(guān)文獻Publishedliterature3參考資料References激光的工業(yè)應(yīng)用-J.F.Rea請記住…..

Remember…..學(xué)習(xí)需要積極的參與Learningrequiresactiveparticipation不恥下問Feelfreetoaskquestions無所顧及地提出個人不同見解Donothesitatetopresentdifferentviewpoints4請記住…..

Remember…..學(xué)習(xí)需要積極的參與4光Light光是一種電磁輻射Lightiselectro-magneticradiation我們聽不到.Wavesthatyoucannothear可見光的波長在0.4-0.7微米之間。Visiblefrom0.4-0.7micronwavelength波長小于0.4微米是紫外線和X光Below0.4–ultraviolettox-rays波長大于700nm的光為紅外線和微波。Above0.7–infra-redtomicrowaves0.40.7μmμmVisibleGamma x-rayUVIRMicrowaveTVRadio0.01μm0.001μmYAG1μm5光Light光是一種電磁輻射Lightiselec光的吸收和顏色

AbsorptionandColor物體的顏色來源于它反射的光的波長Colorofanobject(wavelengththatitreflects)顏色和光的波長是相關(guān)聯(lián)的。Colorisassociatedwithparticularwavelength黑色和白色代表著什么？Whatisthemeaningofblackorwhitecolor?黑色表面吸收了YAG光，而白色在反射了大部分光。BlacksurfacewillabsorbYAGlightwhilewhitewillreflectmostofit6光的吸收和顏色

AbsorptionandColor物體我們?yōu)槭裁葱枰す猓?/p>

WhydoweneedLasers?材料加工需要吸收很強的光。Absorptionformaterialsprocessingrequiresveryintenselight高強度的光可以通過激光聚焦成光束獲得。Intensitycanbegeneratedbyfocusingabeamoflaserlight普通光不能聚焦成很高的能量密度（或足夠小的點）Ordinarylightdoesnotfocusdowntoahighenoughpowerdensity(orsmallenoughspotsize)手持放大鏡可以把太陽光聚焦讓紙燃燒但是不能把金屬融化Hand-heldlenscanfocussunlighttosetfiretopaperbutnotenoughtomeltmetal7我們?yōu)槭裁葱枰す猓?/p>

WhydoweneedLaseLightandLasers單頻的（單波長）Monochromatic(singlewavelength)校準(zhǔn)的（平行光）Collimated(parallel)激光LaserLight普通光OrdinaryLight很多波長Manywavelengths不平行Notparallel8LightandLasers單頻的（單波長）MonochLightandLasers激光LaserLight 普通光OrdinaryLight9LightandLasers激光LaserLight激光的聚焦

FocusingofLasers激光LaserLight普通光OrdinaryLight單頻（單波長）和校準(zhǔn)（平行）的光可以聚焦成很小的焦點Monochromatic(singlewavelength)andCollimated(parallel)lightcanbefocusedtoaverysmallspot10激光的聚焦

FocusingofLasers激光Lase激光的種類

TypesofLasers激光能量傳輸LaserPowerDelivery連續(xù)波ContinuousWave(CW)脈沖PulsedQ-開關(guān)Q-switched激光頻率LaserFrequencies基頻和倍頻Fundamentalandmultiples11激光的種類

TypesofLasers激光能量傳輸La連續(xù)光纖激光

ContinuousWaveFiberLasers激光在光纖中產(chǎn)生Laserlightiscreatedinthefiber可在連續(xù)波和脈沖波中使用CanbeusedinpulsedmodeaswellasCW可以被用于焊接和切割Canbeusedforweldingandcutting激光二極管光LaserDiodeLight激光二極管光LaserDiodeLight光纖Fiber12連續(xù)光纖激光

ContinuousWaveFiberL脈沖YAG激光（焊接）

PulsedYAGLasers(Welding)閃光燈開關(guān)產(chǎn)生脈沖Flashlampturnsonandofftocreatepulses光纖用于傳送激光Fiberisusedtotransmitlaserlight閃光燈（光泵）FlashLamp(OpticalPump)全反鏡100%mirror90%反鏡90%mirror光纖Fiber激光棒LaserRod13脈沖YAG激光（焊接）

PulsedYAGLasers脈沖打標(biāo)激光

PulsedMarkingLasersQ-switchingproducesveryshortpulses,10-100nano-secCannotbeusedforweldingLaserlightdelivereddirectly;nofiberFrequencycanbedoubledortripledtogetgreenorUVlightMMRodMirrorsQ-switchGalvoMirrorsFocusLensFrequencyMultiplier(notpresentinallmarkers)14脈沖打標(biāo)激光

PulsedMarkingLasersQGalvo-光學(xué)器件

Galvo-Optics經(jīng)常用于打標(biāo)。Oftenusedformarkingapplications逐漸受到焊接應(yīng)用的青睞。IsgainingpopularityforweldingapplicationsNutfield,Inc.LaserWJMTechnologies15Galvo-光學(xué)器件

Galvo-Optics經(jīng)常用于打標(biāo)。激光頻率

LaserFrequencies上表只包括了大部分常用的和商業(yè)化的激光器。Tableincludesonlythemostcommonandcommercializedlasers。波長WavelengthRange激光種類Laser頻率Frequencies(mm)遠(yuǎn)紅外FarIRCO210.64近紅外NearIRNd:YAG1.064可見光VisibleFrequencydoubledYAGCopper-VaporLasers0.5320.510紫外光UVFrequencytripledYAGFrequencyquadrupledYAGExcimer0.3540.2660.15-0.3516激光頻率

LaserFrequencies上表只包括了大部脈沖YAG激光焊接典型示意圖

TypicalLayoutforPulsedYAGWeldingLasers鍍膜反光鏡CoatedMirrors激光Laser光纖OpticalFiber聚光頭FocusHead工件Workpiece透鏡Lens注：某些激光不通過光纖直接傳輸。Note:Somelasersaredelivereddirectwithoutfiber17脈沖YAG激光焊接典型示意圖

TypicalLayout聚焦高度和焦點尺寸

Focusheightandspotsize短焦距透鏡將光束聚焦成更小的點。Shortfocallengthlens(ofgivendiameter)willfocusthebeamtoasmallerspot高的能量密度。HigherenergydensityFocusheightiscriticalduetoshallowdepthoffocusLensprotectionfromworkpiecespatterisimportant短焦距ShortFocalLength長焦距LongFocalLengthDepthofFocusSpotSize18聚焦高度和焦點尺寸

FocusheightandspoTimeShareAsinglelasercanbeusedformultipleapplicationsonatimesharedbasis基于同一個理論,單雷射可以一次性用于多種應(yīng)用.Mostconvenientwithtransmissionthroughopticalfiber通過可見纖維的轉(zhuǎn)換是最方便的.Processingstationscanbeindifferentrooms工作臺可以放在不同的房間.Mirrors(100%Reflective)全反鏡19TimeShareAsinglelasercanbEnergyShareLaserenergysplitintomultiplefragments雷射能量分成多個部分Typicallythreeoutputsforcircumferentialspotwelding典型的是圓周點焊接的3份輸出量Mirrors(PartiallyReflective)反光鏡(部分反光)33% 50%100%30W10W10W10W20EnergyShareLaserenergysplitTotalInternalReflection完全內(nèi)反射Lightpropagationthroughfibersdependsontotalinternalreflection通過光纖的光線傳播完全取決于完全內(nèi)反射Air空氣Glass玻璃Core核Cladding覆層ProtectiveSheath接地屏蔽21TotalInternalReflection完全內(nèi)反射OpticalFibers光學(xué)纖維Singlemodehasverysmallcorediameter,<10microns單模式只有很小的直徑<10微米Usedfortelecommunicationsandnowforfiberlasers用于電訊,現(xiàn)用于光纖激光SIandGIhavecoresfrom0.1mmto1mm單模式和分級模式的核從0.1mm到1mmHigherdiameterforhigherpowerlevel能量級別越高直徑越大SteppedIndex(SI)步長指數(shù)SingleMode單模式GradedIndex(GI)分級模式IndexProfiles剖面指數(shù)22OpticalFibers光學(xué)纖維SinglemodeSIvs.GI單模式vs分級模式

SIandGImostfrequentlyusedinmaterialsprocessing單模式和分級模式

多用于材料加工過程.SIoutputis“top-hat”

independentofinput單模式的輸出獨立于輸入呈大禮帽狀morerobust更有活力GIoutputmorefaithfulrepresentationofinput分級模式的輸出與輸入呈保持靠近,Cancreateproblemsifinputbeamqualitychanges如果輸入光束的質(zhì)量改變可能會產(chǎn)生問題.Canmakedeeperwelds/cuts可能焊接/切的更深.Weldprofilescouldchangebasedonfocusheight焦點高度可能產(chǎn)生焊接側(cè)面的變化SIGI0.6AspectRatio縱橫比1.5“TopHat大禮帽狀”WeldProfiles焊接剖面23SIvs.GI單模式vs分級模式

SIandGIFiberInputAlignment光纖輸入排列GoodAlignment好的排列Couldburnfiberinputend可能燒焦光線輸入莫端Couldcreateplasmaatfocus在焦點產(chǎn)生等離子體Couldburncladding可能燒傷覆層24FiberInputAlignment光纖輸入排列GooSpotSizewithFiber光點直徑帶光纖Spotsizeisanimageoftheoutputcorediameterofthefiber從光點的大小可以反應(yīng)出光纖核直徑的大小Sizedependsonmagnificationofthetwolensesinthefocushead其大小是由鏡頭前的兩個透鏡來決定的.OpticalFiber光纖CoreDiameter核直徑SpotSize光點直徑25SpotSizewithFiber光點直徑帶光纖SpoLaserSafetyCommonSense常識Doyounotputyourhandindirectpathofalaserbeam不要把手的頭放在雷射光束的路徑中.Donotlookdirectlyatalaserbeam不要直視雷射光束evenatthoselaserpointersbeams!不要看雷射點.Donotlookatanylaserprocesswithanakedeye不要用不防護的肉眼看任何的激光過程.useplasticsafetyglassesforCO2lasers用塑料防護眼鏡來防護CO2雷射.useYAGsafeglassesforYAGoperations在釔鋁石榴石操作中用釔鋁石榴石安全眼鏡26LaserSafetyCommonSense常識26EyeDamageNearUVfromweldingplasmaandUVlasersIfyouseebluishwhiteduringmaterialprocessing,youneedUVprotection;ordinaryplasticsafetyglassesarenotsufficient!如果你在材料加工的過程中看見藍(lán)白的光,你需要UV保護,一般的塑料防護眼鏡是不起作用的.VisibleandNearIRfromYAGandfrequencydoubledlasersCornea角膜Lens透鏡子Retina視網(wǎng)膜FarUVandFarIRNearUV接近UVVisibleandNearIR27EyeDamageNearUVfromweldingCollateralDamageFumes煙Solvents,grease,etc.fromtheworkpiece溶劑,油脂等,Metaldustcouldbetoxic金屬顆粒可能有毒.Decompositionproductsofplasticsprocessing(marking,welding,ordrilling)couldalsobetoxic在朔料加工的規(guī)程中的分解產(chǎn)品,(打表,焊接,或者鉆孔)也是有毒的.Installvacuumpumpsandappropriatefilters安裝真空泵和合適的過濾器.NeedspecialTidustcollectorswhenweldingTiinagloveboxformedicaldeviceapplications當(dāng)在用于醫(yī)療器械的手套盒子中焊接鈦的時候,需要特殊的吸鈦器.28CollateralDamageFumes煙28FireHazard火災(zāi)LaserBeamscanhavebeenknowntocausefires鐳射激光能夠引起火災(zāi).Breaksinopticalfiber光纖削弱Makesureopticalfiberisnotwoundtootightly確保光學(xué)纖維不會太擊傷.LeakageinCO2directopticsLaserbeamwalkingoffworktableontoplasticcoversLaserbeaminteractionwithglovesinaglovebox29FireHazard火災(zāi)LaserBeamscanhLaser-MaterialInteractionForlensandwindows,AandRhavetobesmall對于透鏡和窗戶,A和R應(yīng)該是小的.Formirrors,Rhastohigh對于鏡子,R應(yīng)該高一些ForLaser-basedmaterialsprocessing,AhastobehighandRshouldbelow對于以雷射原理為基礎(chǔ)的材料加工,A要高一些,R應(yīng)該要低一些.IncidentEnergy入射能Reflection反射Absorption吸收Transmission轉(zhuǎn)播I=A+R+T30Laser-MaterialInteractionForInitialReflectivityofMetals金屬的初始反射率Greymetals(AgandAl)arereflectivetoallcolorsinvisiblespectrum灰色金屬(AgandAl)對所有的有色光譜中的顏色都有反射作用.Copperreflectsnearredwavelengthsandabsorbsothers銅在紅色波長附近反射,在其他中吸收.0.00.81.01.010Wavelength(mm)ReflectivityAgCarbonSteel碳鋼NiCuAlNd:YAGCO2Source:IndustrialLaserApplications-JohnReady31InitialReflectivityofMetalsLaserAngle雷射角落Forallweldingapplications,thelasershouldbeangledoffverticaltopreventlaserenergyfromgoingbackintothelasercavityandcausingdamage對于所有的焊接應(yīng)用,雷射應(yīng)該與角落垂直以防雷射能量回到激光腔,引起損失.5degrees32LaserAngle雷射角落ForallweldingAbsorptivityofMaterials材料的吸收率Reflectivityisalsoaffectedbysurfaceroughness,surfaceoxides,partgeometry,andweldpoolshape反射率也是由表面光滑度,表面氧化度,;零件幾何,以及焊接池的形狀.%AbsorbedMeltingPoint熔點Temperature溫度207033AbsorptivityofMaterials材料的吸收LaserWelding鐳射焊接LaserWelding鐳射焊接Configurations結(jié)構(gòu)Gapdimensionsbecomemorecriticalaspartsgetsmaller由于零件尺寸變小,縫隙的尺寸變得更重要ButtWeld對接焊接Gap<0.1ttCap蓋子Can罐子t35Configurations結(jié)構(gòu)GapdimensionsConfigurationsGapdimensionsbecomemorecriticalaspartsgetsmaller由于零件尺寸變小,縫隙的尺寸變得更重要Canweldmultiplelayers罐子多層焊接LapWeldGap<0.15t36ConfigurationsGapdimensionsbConfigurationsPreferconfigurationswherethemoltenmaterialflowsintotheweldinsteadofpullingawayfromit最好的形狀是融化的物質(zhì)是流入到焊接而不是脫離焊接.LapWeldLapFilletLapEdge37ConfigurationsPreferconfiguraAnnularWeldsFitupisimportant移動的臺面很重要.Ifgapispresent,stresseswilldeveloptowardstheendoftheweld如果有縫隙,應(yīng)力會隨著焊接而增大Press-fitpreferred最好有壓配合.38AnnularWeldsFitupisimportanSmallVolumeWeldsAir/gasintheenclosedvolumeduringfinalweldheatsupandtriestoescape空氣在有限的空間里會隨著焊接的熱量膨脹,并試圖逸出.Cancauseporositytowardstheendoftheweld可能會在焊接的最后引起多孔.AirPressureIncreasesDuringWelding在焊接餓過程中空氣的壓力增加39SmallVolumeWeldsAir/gasintPressureRelief卸壓Allowpressurereliefonenclosedvolumes

如下情況需要泄壓Reducecrack-likefeatureswhichmaybecausedbyhighpressuretrappedinside泄壓可以減少像這種由于內(nèi)部壓力過大而引起的類似裂紋的缺陷.40PressureRelief卸壓AllowpressurShieldGasMainfunctionofshieldinggasistoprotectthemoltenmetalfromreactingwithoxygen保護氣體的保護作用主要是保護融化的金屬不與氧氣反應(yīng).Shieldinggasalsohelpsto:保護氣體也有助于Protectlens/lenscoverfromweldsplatter保護透鏡,透鏡蓋不受焊接潑濺Controlplasmacloudformation控制等離子霧形成.Washawaymetalvaporsintheplume吹散等離子體中的金屬蒸汽.41ShieldGasMainfunctionofshShieldGasWhatisplasma?什么是等離子體Plasmaisionizedgas等離子是離子化氣體Electronsareseparatedfromatoms(metalaswellasshieldinggas)電子與原子分離(金屬和屏蔽氣體)Plasmaisthefourthstateofmatter;otherthreearesolid,liquid,andgas(等離子體是事物的第四種狀態(tài),其他的三種是固體,液體和氣體)Whatisplume?什么是等離子體?Plumeisamixtureofplasmaandmetalvapors等離子體是等離子以及金屬氣體的混合體.Plume42ShieldGasWhatisplasma?什么是等ShieldGasesforYAGLasersHeliumisidealbutveryexpensive氦很理想,但是很昂貴Argongasismostcommonlyused氬氣是最常用的Nitrogencanbeusedforsomealloys氮可以用于一些合金.Someweldsaremadeinair(noshieldinggas)buttheweldsurfaceisnotverysmooth有些焊接在空氣中做(沒有保護氣體)但是焊接表面不是太順滑Maystillproduceacceptableweldquality可能仍舊能夠產(chǎn)生有效的焊接質(zhì)量.43ShieldGasesforYAGLasersHelSootSootisblackcoloreddust,typicallyreferredtoas“soot”thoughitisnotcomposedofcarbon煙是黑色的灰塵,雖然叫煤煙但它不是由碳組成的.“Soot”isafinedustofmetalpowderthatisdepositedfromtheplume煤煙是一種從等離子中沉淀下來的金屬粉末.Chemicalanalysisof“soot”fromInconel60044SootSootisblackcoloreddustShieldGasConfigurationCoaxial共軸Toohigh–destabilizestheweldpool,increasedporosity太高-動搖焊接溶池,引起多孔.Toolow–cancausenegativepressureandpulluptheweldmetal太低-會引起負(fù)壓力,使融化的金屬突起.Betterforshielding最好屏蔽SideFlow側(cè)流Usefulforsweepingawaytheionizationproducts用于清理等離子體.45ShieldGasConfigurationCoaxiaPulsedYAG脈沖釔鋁石榴石ImportantParameters重要的參數(shù)Pulse脈沖Width寬度Energy能量Power能量Shape形狀PulseOverlap脈沖交迭SpotSizeandFocus光點和焦點46PulsedYAG脈沖釔鋁石榴石ImportantPaPulsedYAG脈沖釔鋁石榴石Energy(J)能量=Power(kW)力xWidth寬度(msec)Initialenergypeakhelpsthelaserenergytocouplewiththematerial初始的高能量可以使激光能量與金屬耦合..ProgrammedPulse程序脈沖PeakPowerPulseEnergy脈沖能量PulseWidth脈沖寬度ActualOutput實際輸出47PulsedYAG脈沖釔鋁石榴石Energy(J)能量PulsedYAG脈沖釔鋁石榴石Shortpulseofhighpeakpowercancauseexpulsion高的峰值能量的短脈沖能引起坑.Longpulseoflowpeakpowerwillproduceawiderandshallowerweldbead低頂點能量的長脈沖會產(chǎn)生更寬和更淺的焊縫.PowerPulseWidthDeeperPenetration更深穿透GreaterPorosity更多多孔MoreExpulsion/Spatter更多飛濺ShallowerPenetration更淺穿透LessPorosity更少多孔Cleanerweldswithnoporosity更干凈焊接沒有飛濺48PulsedYAG脈沖釔鋁石榴石ShortpulseoEffectofpulsetimeonweldsize脈沖時間對焊接尺寸的影響Weldspotdiameterincreasesrapidlyinthefirstfewmilli-seconds;rateofgrowthreduceswithtime焊斑直徑在最初的千分之一秒期間迅速變大,增長的速度隨著時間的增長而降低.

TimeWeldSize49EffectofpulsetimeonweldsEffectofpulsetimeonpenetration

脈沖時間對焊接尺寸的影響Foragivenpeakpower,weldpenetrationstabilizesafteracertainthresholdweldtime對于指定的能量高峰,焊接深度在一定的焊接時間后變得穩(wěn)定.Maximumpenetrationisdirectlyproportionaltopeakpower最大的深度是與能量高峰成直接正比的關(guān)系.Aboveacertainthresholdofpower,thelaserwillendupdrilling/cutting/gouginginsteadofwelding在一定能量的之上,雷射將鉆孔,切斷,咆削而不是焊接.TimePenetrationPeakPower1PeakPower250EffectofpulsetimeonpenetrPulseShaping脈沖形狀Singlepulseorthreesectorpulseofferedbycapacitorbasedpowersupplies由電源電容器產(chǎn)生的單脈沖和三個脈沖Newermachinesofferinvertertechnologywithcontinuouspulseshaping更新的提出的能夠提供無間斷的脈沖形狀.Time(msec)PeakPowerEnergy(J)能量=Power(kW)力xTime時間(msec)Single單個Three-sector三部分 Multi-sector多部分51PulseShaping脈沖形狀SinglepulseWeldCracking焊接破裂Canisanchoredinthecapwhilecansurfacehasleverage罐子被錨在夾具中,而罐子的表面有杠桿作用.Weldcoolingalwaysintroducesresidualstresses焊接冷卻往往引起殘余壓力.Combinationoflargeweldvolumeandrapidcoolingcanintroduceexcessiveresidualstressesthatcausecracking大量焊接加之迅速冷卻能產(chǎn)生過量的殘余壓力從而引起破裂.Can罐子(AnchoredinClamp錨在夾具中)52WeldCracking焊接破裂CanisanchorLaserFeatures:PulseShape雷射特征:脈沖形狀MeltingandPenetrationPulse溶解滲透脈沖(CouplingPulse偶合脈沖)StabilizationPulse穩(wěn)定脈沖(controlledcoolingtoreduceexpulsionandresidualstresses控制冷卻減少殘余應(yīng)力.)6.0kW 2.0m-sec50%30%0.253LaserFeatures:PulseShape雷射特PulseShaping脈沖形狀Modifiedpulsegavetimefortheweldtocoolslowlyandallowthepore

toriseabovetheweldinterface改良脈沖使焊接冷卻的時間變慢,而且使得氣孔有時間從熔融的金屬中上升到表面SquarePulse方形脈沖Modified改良的54PulseShaping脈沖形狀ModifiedpulsFocusHeight焦點高度Atfocus,spotsizenotsensitivetofocusheight在焦點,點大小與焦點高度不相互影響.Atfocus,plumeistallestandsoundishighestpitch在焦點,等離子體是最高的,而且聲音也是最高調(diào)的.usedtofindfocusheight用于找出焦點高度.Focususuallysetatthesurfaceforpulsedwelding焦點通常設(shè)在表面為脈沖焊接.Focussetbelowsurfacefordeeperpenetrationandkeyholemodewelding焦點射在表面以下為更深的穿透和縮定焊接55FocusHeight焦點高度Atfocus,spoPulseOverlap脈沖交疊Dependsonthicknessofcomponentontopandshapeofweldbead取決于零件上端的厚度和焊縫的形狀.Overlapshouldbegreaterbyasafemargin在一定安全范圍之內(nèi),交疊會大一些.Note:Excessiveoverlapisexcessunwantedheatintotheweld注意:過量的交疊是過度的熱量在焊接中出現(xiàn).Non-hermeticOverlap不密封交疊HermeticOverlap密封交疊56PulseOverlap脈沖交疊DependsonthPulseOverlap脈沖重疊Lapweldsrequirehigheroverlap重疊焊接要求更高的重疊Buttweldscanbehermeticevenat50%overlap對接焊接可以被密封,即便是50%的重疊ButtWeld對接焊接LapWeld重疊焊接ButtWeld對接焊接57PulseOverlap脈沖重疊LapweldsreqLaserWeldQuality雷射焊接質(zhì)量WeldSurfaceInspection焊接表面檢測Weldsurfaceshouldbecleanandfreeofspatter焊接表面需干凈,沒有滴濺Novisiblecracksorholes沒有可見的裂縫和孔.GoodNotGood58LaserWeldQuality雷射焊接質(zhì)量WeldLaserWeldQuality雷射焊接質(zhì)量MechanicalTesting機械測試BurstStrength爆發(fā)力量PulltestorShearTest拉力測試和剪切測試LeakTest測漏測試StrengthAnalysis;力量分析Itisveryimportanttokeeptrackofwhereandwhenthefailuresoccurredduringtesting在測試中,記錄在那里和什么時候失敗是十分重要的Marklocationsoffailureforfurtheranalysis在失敗的地方做標(biāo)識是以便將來進一步分析59LaserWeldQuality雷射焊接質(zhì)量MechanWeldSectionAnalysis焊接部分分析CrackedWeld焊接破裂SmallPressureBubble?小壓力泡沫GoodWeld好焊接60WeldSectionAnalysis焊接部分分析CraX-rayAnalysisX-RAY分析Cracksgrowatanangleandappearasstraightlinesinthex-ray(shallowweldonright)[破裂在一個角中擴大,在X-RAY中顯示為一條直線Smallporositiesmaybedifficulttoseeinsuchimages在這樣的圖片中很難看到小孔.Checkforalignment查看齊邊.WeldCrack焊接破裂ShallowWeld焊接陰影Alignment61X-rayAnalysisX-RAY分析CracksgX-rayimagesofgoodweldsX-RAY中好的焊接62X-rayimagesofgoodweldsX-RALaserMaintenance雷射維護Feedbackmonitoronlycheckslasercavityperformance–doesnotcheckpoweratweld反饋器只查看激光腔的性能-不會查看焊接時候的能量LaserCavity激光腔FocusHead焦點頭EnergyMeter,BurnMarks,Plexiglas,etc.能量劑,火刺,樹脂玻璃Lens透鏡FeedbackMonitor監(jiān)視器反饋63LaserMaintenance雷射維護FeedbackEnergyMeters能量計JouleMeters焦耳Setforsinglepulseoraverageovermultiplepulses定為單脈沖或者平均大于多脈沖Shouldbeusedperiodicallytoconfirmenergyattheweld在焊接的時候周期性的確認(rèn)能量Automationsystemcanbesetformeasurementatwarmupandaftersetnumberofpulsewelds在啟動的時候或者確定脈沖焊接的時候用自動化系統(tǒng).來確定量度.64EnergyMeters能量計JouleMeters焦耳Spotsizeandshape黑點的大小和形狀Burnpaperandburnplates燒紙Firelaserspotsatlowenergyandobserveburnmarkpatternforsymmetryanduniformity用低能量去燒雷射黑點觀察出來的標(biāo)記是均勻?qū)ΨQ的.Ifspotisnotroundinshape,beamisbeingcut/clipped如果黑點不是圓形的,光束就正被切斷.Makingspotsonactualmaterialatlowenergyandobservespotsunderamicroscope在具體的材料上用低能量下做黑點,并且在顯微鏡下觀察.Canbeusedforsettingspotsizeandfocus用來設(shè)定黑點的大小和焦距.65Spotsizeandshape黑點的大小和形狀BurFiber,Lens,andLensCover光纖,透鏡和透鏡蓋Makesuretofollowalignmentinstructionsprovidedbymanufacturer確保能夠按照廠商提供的對齊要求來操作.Periodicallyinspectfocuslensfordamage周期性地檢測焦點透鏡是否受損Cleanverygentlywithlenscleaningcloth/paperonly只用干凈的擦鏡布輕輕的擦透鏡Alllenseshavespecialcoatingthatcannotbeseenandisveryeasilydamaged所有的透鏡都有一層看不見的特殊涂層而且比較容易受損.Inspectlenscoveratbeginningofeveryshiftandcleancarefully觀測透鏡在每一次的切換開始的時候,并且要仔細(xì)擦干凈.Ifexcessiveweldsplattercheckshieldgasflowrate如果有過多的焊接潑濺檢查保護氣體的流率66Fiber,Lens,andLensCover光纖,MachineAlignment機齊邊器Laserpathandseammaynotbewellalignedduetomachineoffset雷射路徑和焊蜂可能會不齊由于機器騙移Runspotweldpatterntocheckalignment啟動焊接模式檢查齊邊Runoutshouldbelessthan0.1mm偏移應(yīng)該要低于0.1MMLaserPathWeldSeam67MachineAlignment機齊邊器LaserpatSummary總結(jié)Laserlightismonochromaticandparallelmakingitpossibletofocusdowntoverysmallspot雷射光是單頻率和平行的使得它能夠在很小的黑點上聚焦Laserweldingisanon-contacthigh-powerprocessthatcanproducespotweldsandseamwelds,andcanalsobeusedformarkingandcutting雷射焊接是一種能產(chǎn)生黑點焊接和接縫焊接不可以接觸的高能量工序,可以用來打標(biāo)和切割I(lǐng)mportantfactorsincludepulsetime,focus,peakpower,andoverlap(forseamwelds)重要因素包括脈沖時間,頂點能量和交疊(接縫焊接)Laserweldpowershouldbemonitoredwithanenergymeterandweldqualitycanbeinspectedwithmechanicaltesting,x-ray,andcross-sections雷射能量應(yīng)該用能量計監(jiān)控.焊接質(zhì)量可以用一些機械測試來檢測X-RAY68Summary總結(jié)Laserlightismonoch激光焊接

LasersWelding

GirishP.Kelkar,Ph.D.激光焊接

LasersWelding

GirishP.激光LASER受激輻射式光頻放大器的英文第一個字母的縮寫LightAmplificationbyStimulationofEmittedRadiation70激光LASER受激輻射式光頻放大器的英文第一個字母的縮寫2參考資料References激光的工業(yè)應(yīng)用-J.F.ReadyIndustrialApplicationsofLasers,J.F.Ready激光焊接，W.W.DuleyLaserWelding,W.W.Duley激光加工，W.M.SteenLaserMaterialsProcessing,W.M.SteenAWS焊接手冊，1-4AWSWeldingHandbooks,1-4激光加工手冊-美國激光協(xié)會出版HandbookofLaserMaterialsProcessingPublishedbytheLaserInstituteofAmerica公開的相關(guān)文獻Publishedliterature71參考資料References激光的工業(yè)應(yīng)用-J.F.Rea請記住…..

Remember…..學(xué)習(xí)需要積極的參與Learningrequiresactiveparticipation不恥下問Feelfreetoaskquestions無所顧及地提出個人不同見解Donothesitatetopresentdifferentviewpoints72請記住…..

Remember…..學(xué)習(xí)需要積極的參與4光Light光是一種電磁輻射Lightiselectro-magneticradiation我們聽不到.Wavesthatyoucannothear可見光的波長在0.4-0.7微米之間。Visiblefrom0.4-0.7micronwavelength波長小于0.4微米是紫外線和X光Below0.4–ultraviolettox-rays波長大于700nm的光為紅外線和微波。Above0.7–infra-redtomicrowaves0.40.7μmμmVisibleGamma x-rayUVIRMicrowaveTVRadio0.01μm0.001μmYAG1μm73光Light光是一種電磁輻射Lightiselec光的吸收和顏色

AbsorptionandColor物體的顏色來源于它反射的光的波長Colorofanobject(wavelengththatitreflects)顏色和光的波長是相關(guān)聯(lián)的。Colorisassociatedwithparticularwavelength黑色和白色代表著什么？Whatisthemeaningofblackorwhitecolor?黑色表面吸收了YAG光，而白色在反射了大部分光。BlacksurfacewillabsorbYAGlightwhilewhitewillreflectmostofit74光的吸收和顏色

AbsorptionandColor物體我們?yōu)槭裁葱枰す猓?/p>

WhydoweneedLasers?材料加工需要吸收很強的光。Absorptionformaterialsprocessingrequiresveryintenselight高強度的光可以通過激光聚焦成光束獲得。Intensitycanbegeneratedbyfocusingabeamoflaserlight普通光不能聚焦成很高的能量密度（或足夠小的點）Ordinarylightdoesnotfocusdowntoahighenoughpowerdensity(orsmallenoughspotsize)手持放大鏡可以把太陽光聚焦讓紙燃燒但是不能把金屬融化Hand-heldlenscanfocussunlighttosetfiretopaperbutnotenoughtomeltmetal75我們?yōu)槭裁葱枰す猓?/p>

WhydoweneedLaseLightandLasers單頻的（單波長）Monochromatic(singlewavelength)校準(zhǔn)的（平行光）Collimated(parallel)激光LaserLight普通光OrdinaryLight很多波長Manywavelengths不平行Notparallel76LightandLasers單頻的（單波長）MonochLightandLasers激光LaserLight 普通光OrdinaryLight77LightandLasers激光LaserLight激光的聚焦

FocusingofLasers激光LaserLight普通光OrdinaryLight單頻（單波長）和校準(zhǔn)（平行）的光可以聚焦成很小的焦點Monochromatic(singlewavelength)andCollimated(parallel)lightcanbefocusedtoaverysmallspot78激光的聚焦

FocusingofLasers激光Lase激光的種類

TypesofLasers激光能量傳輸LaserPowerDelivery連續(xù)波ContinuousWave(CW)脈沖PulsedQ-開關(guān)Q-switched激光頻率LaserFrequencies基頻和倍頻Fundamentalandmultiples79激光的種類

TypesofLasers激光能量傳輸La連續(xù)光纖激光

ContinuousWaveFiberLasers激光在光纖中產(chǎn)生Laserlightiscreatedinthefiber可在連續(xù)波和脈沖波中使用CanbeusedinpulsedmodeaswellasCW可以被用于焊接和切割Canbeusedforweldingandcutting激光二極管光LaserDiodeLight激光二極管光LaserDiodeLight光纖Fiber80連續(xù)光纖激光

ContinuousWaveFiberL脈沖YAG激光（焊接）

PulsedYAGLasers(Welding)閃光燈開關(guān)產(chǎn)生脈沖Flashlampturnsonandofftocreatepulses光纖用于傳送激光Fiberisusedtotransmitlaserlight閃光燈（光泵）FlashLamp(OpticalPump)全反鏡100%mirror90%反鏡90%mirror光纖Fiber激光棒LaserRod81脈沖YAG激光（焊接）

PulsedYAGLasers脈沖打標(biāo)激光

PulsedMarkingLasersQ-switchingproducesveryshortpulses,10-100nano-secCannotbeusedforweldingLaserlightdelivereddirectly;nofiberFrequencycanbedoubledortripledtogetgreenorUVlightMMRodMirrorsQ-switchGalvoMirrorsFocusLensFrequencyMultiplier(notpresentinallmarkers)82脈沖打標(biāo)激光

PulsedMarkingLasersQGalvo-光學(xué)器件

Galvo-Optics經(jīng)常用于打標(biāo)。Oftenusedformarkingapplications逐漸受到焊接應(yīng)用的青睞。IsgainingpopularityforweldingapplicationsNutfield,Inc.LaserWJMTechnologies83Galvo-光學(xué)器件

Galvo-Optics經(jīng)常用于打標(biāo)。激光頻率

LaserFrequencies上表只包括了大部分常用的和商業(yè)化的激光器。Tableincludesonlythemostcommonandcommercializedlasers。波長WavelengthRange激光種類Laser頻率Frequencies(mm)遠(yuǎn)紅外FarIRCO210.64近紅外NearIRNd:YAG1.064可見光VisibleFrequencydoubledYAGCopper-VaporLasers0.5320.510紫外光UVFrequencytripledYAGFrequencyquadrupledYAGExcimer0.3540.2660.15-0.3584激光頻率

LaserFrequencies上表只包括了大部脈沖YAG激光焊接典型示意圖

TypicalLayoutforPulsedYAGWeldingLasers鍍膜反光鏡CoatedMirrors激光Laser光纖OpticalFiber聚光頭FocusHead工件Workpiece透鏡Lens注：某些激光不通過光纖直接傳輸。Note:Somelasersaredelivereddirectwithoutfiber85脈沖YAG激光焊接典型示意圖

TypicalLayout聚焦高度和焦點尺寸

Focusheightandspotsize短焦距透鏡將光束聚焦成更小的點。Shortfocallengthlens(ofgivendiameter)willfocusthebeamtoasmallerspot高的能量密度。HigherenergydensityFocusheightiscriticalduetoshallowdepthoffocusLensprotectionfromworkpiecespatterisimportant短焦距ShortFocalLength長焦距LongFocalLengthDepthofFocusSpotSize86聚焦高度和焦點尺寸

FocusheightandspoTimeShareAsinglelasercanbeusedformultipleapplicationsonatimesharedbasis基于同一個理論,單雷射可以一次性用于多種應(yīng)用.Mostconvenientwithtransmissionthroughopticalfiber通過可見纖維的轉(zhuǎn)換是最方便的.Processingstationscanbeindifferentrooms工作臺可以放在不同的房間.Mirrors(100%Reflective)全反鏡87TimeShareAsinglelasercanbEnergyShareLaserenergysplitintomultiplefragments雷射能量分成多個部分Typicallythreeoutputsforcircumferentialspotwelding典型的是圓周點焊接的3份輸出量Mirrors(PartiallyReflective)反光鏡(部分反光)33% 50%100%30W10W10W10W88EnergyShareLaserenergysplitTotalInternalReflection完全內(nèi)反射Lightpropagationthroughfibersdependsontotalinternalreflection通過光纖的光線傳播完全取決于完全內(nèi)反射Air空氣Glass玻璃Core核Cladding覆層ProtectiveSheath接地屏蔽89TotalInternalReflection完全內(nèi)反射OpticalFibers光學(xué)纖維Singlemodehasverysmallcorediameter,<10microns單模式只有很小的直徑<10微米Usedfortelecommunicationsandnowforfiberlasers用于電訊,現(xiàn)用于光纖激光SIandGIhavecoresfrom0.1mmto1mm單模式和分級模式的核從0.1mm到1mmHigherdiameterforhigherpowerlevel能量級別越高直徑越大SteppedIndex(SI)步長指數(shù)SingleMode單模式GradedIndex(GI)分級模式IndexPro