《粉末喷涂与应用》PPT课件.ppt

IntroductiontoPowderCoating粉末涂料介绍,MetalPretreatmentforusewithPowderCoatings金属前处理,MetalPreparation金属的处理,Pretreatmentisaprocessintendedtopreventthecorrosionofthepaintedmetal.前处理是一种提高耐腐蚀的工艺,Fe2+O2+H2O=RUST,Ironreactswithoxygenandwaterintheatmospherecreatingapowderybrownmess,notveryornamental,andcontinuousuntilnosolidmetalremains.铁在空气中会与氧气和水反应生成褐色的物质,MetalPreparation金属处理,Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForSteel:铁：Automotiveapplications汽车业Primer:Underseals:LayersofPaint.,Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForSteel:铁：ArchitecturalApplications建筑业Galvanising:AntiCorrosivePrimer*Galvanisingcoveringwithalayerofzinc.,MetalPreparation金属处理,MetalPreparation金属处理,MetalPreparation金属处理,Severalmethodsofcorrosionpreventioncanbeused几种防腐蚀的方法ForAluminium:铝：Aluminiumoxidisestoformawhitecorrosionproduct铝被氧化后形成白色的物质ArchitecturalApplications建筑业Anodise:AcidPrimers,MetalPreparation金属处理,WhyPretreatment?为什么要前处理？,Powdercoatingsareusedtoenhancetheappearanceofbuildings,machines,furniture,appliances:粉末涂料用于改善建筑，机械设备，家具，以及其它器具的表面：Designersandarchitectsaresearchingtogivedistinctionintermsofcolourandeffects.设计师和建筑师提供了包括颜色和效果在内的标准等级Theproblemisthatallpaintsareporous：所有的涂料均不同程度的存在会渗水的小孔,MetalPreparation金属处理,Moleculesofwaterandsaltcanpenetratethroughthepaintfilm.Whentheyreachthemetalsurfacetheeffectisworsethanifthemetalisuncoated.Theanswer=Pretreatment水和盐分子可以渗透漆膜，一旦它们与金属表面接触，产生的影响甚至比没有喷涂还要糟糕。要解决这个问题就需要前处理。,MetalPreparation金属处理,Pretreatment:前处理Thechemicalconversionofthemetalsurfacebeforeapplyingthepowdercoating.Themetalthenresistscorrosionandtheconversionpermanentlyimprovestheadhesionofthecoating.在使用粉末涂料以前用化学方法对金属表面进行处理，可以改善耐腐蚀性和增加涂层的附着力。,MetalPreparation金属处理,Theperformanceofthepowdercoatingisonlygoingtobeasgoodasthemetalpreparation.Wewillcoverthreetypesofmetaltreatmentsystems粉末涂料的功能类似于金属处理，我们将介绍三种的金属处理方法IronPhosphateforSteel用于铁系的磷酸铁ZincPhosphateforSteel用于铁系的磷酸锌ChromateforAluminium用于铝的铬酸盐Othersystemscanbeusedandinformationisavailable.当然还有其它处理方法,MetalPreparationIronPhosphate金属处理磷酸铁,Metalpretreatmentcanbeappliedbysprayordipping.金属前处理可以借助喷淋或浸渍,Inthecaseofironphosphatetheprocesscouldlooklikethis:下面是磷酸铁的工艺流程,Stages1,2and3canbeeithersprayordip步骤1，2和3均可采用喷淋或浸渍,DRAIN,DRAIN,Stage1Clean&Phosphate,Stage2Rinse,Stage3Rinse&Seal,WorkFlow,MetalPreparationIronPhosphate金属处理磷酸铁,Typical3StageSystem典型的3步骤流程MetalSubstrateSteelPhosphatisingSystem金属基材NoneFerrousCleanandEtchStagetimeduration190seconds不同步骤所需的时间245seconds330secondsStagetemperature1，2和3步骤所需的温度4060oCDrying/干燥温度100120oCTypicalconcentration23%byvolume典型的浓度Typicalacidity典型的酸值pH3.55.5Typicalcoatingweight典型的膜重2040mg/ft.,MetalPreparationZincPhosphate金属处理磷酸锌,ZincPhosphateprocessforsteeltendstobemorecomplicated磷酸锌的工艺流程复杂一些,Stage1Clean,Stage2Rinse,Stage3Phos-phate,Stage4Rinse,Stage5Rinse,DRAIN,DRAIN,DRAIN,DRAIN,MetalPreparation金属处理,DwellTime:Eachstagedependson:各阶段所需的时间，受下面的因素控制Theamountofpretreatmentchemicaldissolvedinwater溶于水的前处理化学药品的浓度Theageofthechemical化学药品的有效时间Regularcheckingisrequiredtogiveconsistentgoodresultsatleasttwicepershift.通常要经常检查前处理的状态一个班至少两次,MetalPreparationZincPhosphate金属处理磷酸锌,Typical5StageSystem典型5步骤流程MetalSubstrateSteelPhosphatisingSystem金属基材NoneFerrousCleanandEtchStagetimeduration190seconds不同步骤所需的时间245seconds360seconds430seconds530secondsStagetemperature温度4060oCDrying干燥温度100120oCTypicalconcentration典型浓度24%byvolumeTypicalacidity1=alkaline酸碱性2=acidicTypicalcoatingweight4070mg/ft.典型的膜重,MetalPretreatment-BS3189Type3,SprayPhosphatePlant,9stagepretreatment九步法Degrease脱脂Rinse水洗Rinse水洗Rinse水洗AcidEtch(phosphoricacid)表调ZincPhosphate磷酸锌磷化Rinse水洗Rinse水洗De-ionisedwater去离子水水洗Dry干燥QualityStandardBS6497参考英国标准BS6497,MetalPretreatmentQualityControl金属前处理质量控制,TitrationChecks:检测项目：1.Cleaner2.Rinses3.AcidConcentration4.Rinse5.PhosphateConcentrationandcoatingweight7.Rinse8.ObservationsCheckedatregularintervalsduringnormalproductionandbeforeproductioncommences以上项目应在生产过程中定时和生产前进行检验,MetalPretreatmentDry金属前处理干燥,Toensuremetalsurfaceisdryreadyforpowdercoating.在喷涂粉末涂料前必须保证金属工件已经完全干燥,Dryingoven-PhosphatePlant,MetalPreparationChromate金属处理鉻酸盐,Foraluminiumchromateconversion铝铬酸盐处理,BritishStandardsexistfortheconversionofaluminiumBS6496适用于铝的英国标准BS6496ThesameconversioncanbeusedforGalvanisedsteel-BS6497适用于电镀铁的英国标准BS6497,Stage1Clean,Stage2Rinse,Stage3Etch,Stage4Rinse,Stage5Chrom-ate,Stage67Rinse,Stage8DeminRinse,DRAIN,DRAIN,DRAIN,DRAIN,DRAIN,DRAIN,MetalPreparationChromate金属处理鉻酸盐,Typical7StageSystem七步法MetalSubstrateAluminium/AluminiumAlloys金属基材GalvanisedSteelCleanandEtchStage1CleaningStage2RinseStage3DeoxidisemetalsurfaceStage4RinseStage5ChromateStage6RinseStage7AcidulatedRinseStageTemperature80100oCDrying9095oCDonotoverheatatthedryoffstage干燥温度不能过高,MetalPreparationChromate金属处理鉻酸盐,ChromateconversiontoAluminiumandGalvanisedsteel鉻酸盐处理完铝和电镀铁后的变化,YellowChromateConversionTypicalCoating黄色鉻酸盐的变化Weight(g/m2)PaleYellow0.20.7Gold0.71.6Brown1.63.5Greenmixchromate/phosphate0.52.0,ForPowderCoatingalightweightcoatingisrecommendedIntherange0.22.0g/m2应用于粉末涂料，膜重一般在0.22.0g/m2,SprayingandApplicationofPowderCoatings粉末涂料的喷涂与应用,PowderApplicationSystems粉末涂料的应用系统,PowderApplicationSystemsFeedSystems粉末涂料应用系统供粉系统,DirectfeedsystemfromDrumtoGun.粉末涂料直接从粉桶送至喷枪Thesystemshownfeeds1gun右图是只供一个喷枪的直接供粉系统,PowderApplicationSystemsFeedSystems粉末涂料应用系统供粉系统,Directfeedsystemdirectlyfroma25kilobox.Thissystemissetuptofeed2guns.Usedmainlyinmanualoperations.右图为直接从粉末涂料的包装箱至喷枪的供粉系统。图中的设备适用于两把喷枪，通常用于人工喷涂。,PowderApplicationSystemsFeedSystems粉末涂料应用系统供粉系统,Bulkfeedsystem,powderissuppliedinafibrebag.Weightofpowderupto1,000kilosperbag.Usedmainlyonautomaticplantswherecolourchangeislimited.大型供粉系统，粉末涂料一般1吨一个包装，用于自动喷涂系统，限于换色较少的场合。,PowderFluidisationSystems粉末涂料流化系统,Dryairpassesthroughamembranegivingthepowderliquidqualities.干燥的空气通过微孔板，使粉末涂料象水一样流动。,Theairmustbedryandfreefromwaterandoil.空气必须除水和油,PowderDeliverySystems粉末涂料的传送系统,PowderDeliverySystems粉末涂料的传送系统,ActualpowderfeedsystemVenturifeedfromfluidbed.右图是用文氏管从流化床吸取粉末的送粉系统,ForcesatworkonthePowderParticles,Atanyonetime4forcesareatworkonthepowderparticleasittravelsfromtheguntotheearthedwork-piece.粉末在离开喷枪到达工件时受4种力的影响AirResistanceElectrostaticAttractionWeight(Gravity)AerodynamicForce,PowderChargingSystems,Thereare2majorcategoriesinchargingofpowdercoatingcoronaandtribo:粉末涂料主要有两种带电方法静电/摩擦,GunTypeChargeLocation充电位置InternalExternalRemotePowderSupplyXXCorona静电法IntegratedGunPowderSupplyXXTribo摩擦带电法X,CoronaChargingSystems静电带电系统,Inthismethod,ahighvoltagegeneratorisusedtochargeanelectrodeatthetipwhichcreatesanelectrostaticfield(orcorona)betweenthegunandthework-piece.利用高压电极使粉末带电，并在喷枪与工件间形成电场,ExternalChargingSystem/外充电系统,CoronaChargingSystems静电带电系统,Coronacharging-manualsystem/手动枪-automaticsystem/自动枪,CoronaChargingSystems静电带电系统,InternalChargingSystem内充电系统,CoronaNozzleSystems静电枪的喷嘴,ThetypeofproducttoBecoatedwillinfluenceThenozzletobeusedontheSpraygun,twotypesareshown,CoronaNozzleSystems静电枪的喷嘴,ConicalSprayNozzlesusedtogiveanevenlydistributedfilmthicknessoverflatpanels.圆锥型的喷嘴一般用于喷涂平面，并得到膜厚均匀的涂层。InterponAFparticlemanagedpowderbeingappliedondomesticappliances.右图为InterponAF粉末涂料用于家用设备,CoronaChargingSystems静电带电法,Thehighvoltagepowersupplychargestheelectrode高压发生器使喷枪电极带电Theconcentratedchargecreatesanelectrostaticfield带上电荷后形成静电场Theelectrostaticfieldcausestheairtoionizeandgenerateacorona静电场使空气电离形成电晕Thecoronaemitselectrons电晕放射出电子Theelectronsarepickedupbyoxygenmoleculesformingnegativeions这些电子借助氧分子形成负离子,CoronaChargingSystemscont.静电带电法,Theionsfollowthefieldlines负离子沿着电力线移动Thepowderparticlesdistortthefieldaroundthem粉末涂料粒子使周围的电力线产生扭曲Thedistortedfieldlinesdirectionstothepowderparticles扭曲后的电力线引导离子被粉末涂料粒子吸附Theionsbombardthepowderparticlesandtransfertheelectronsgivingtheparticlesanegativecharge吸附的离子轰击粉末粒子，并使其带上负电，形成负极,TriboChargingSystems摩擦带电法,Triboelectricityisgeneratedbythefrictionofonematerialonanother.InTribochargedsprayguns,thepowderrubsonaspeciallyformulatedandshapedsurfacewhichallowschargetotransfer.摩擦带电是通过不同物质摩擦形成的，摩擦枪可以使粉末与特殊设计并有特殊结构的表面摩擦而带电,TriboChargingSystems摩擦带电法,TriboChargingSystems摩擦带电法,Tribonozzlesindifferentconfigurations.不同结构的摩擦枪喷嘴,ElectrostaticFluidBedSystems静电流化床法,PowderPenetration粉末的吸附,Thepictureshowsthedevelopmentofthecorona(reddottedarea).Articlespassingthrougharechargedwiththenegativeions(-).Thechargedpowderparticlesareattractedtotheearthedsubstrate.右图显示了电场，电力线，粉末的充电及被接地的工件吸附过程。,PowderPenetration粉末的穿透,Achievingpenetrationintodeeprecessesinmostimportantwhenapplyingpowdercoating.粉末涂料能否到达死角这对粉末涂料的应用来说很重要,ThemosteffectivecontrolsarethenozzlepatternAndairassistance.有效的控制方法是选择合适外形的喷嘴及调整辅助空气,Itispossibletoovercomethe“FaradayCageEffect”现在，克服“法拉第”效应已成为一种可能,PowderPenetration粉末的穿透,Reducingthe“FaradayCage”Effect减弱“法拉第”效应,ToreducetheeffectitisnecessaryToassistinthecreationofchargedairParticlesinsidetherecess.Thisshouldbe彻achievedbyincreasingtheairstream.可以借助加大传送空气的压力来减弱“法拉第”效应,FaradayCageEffect“法拉第”效应,AFaradaycagecantechnicallybedefinedasanareawithinwhichthereisnoelectrostaticfield.Infinishing,thistermisappliedmoreloosely,andgenerallyreferstoanareasuchasinsidecornersorcavitiesthataredifficulttocoat.Thereasonwhytheseareasaredifficulttocoatisthattheadjacentsurfacestotheinsideofthecornerattracttheelectrostaticfiled,thereforedeflectingthepowderfrompenetratingintotherecessedareas.Atthesametime,thisrecessedareaisdifficultfortheaerodynamicforcestopenetrateintowithoutblowingpowderoffalreadycoatedareas.法拉第区域可以被认为是静电屏蔽区。实际应用中定义更宽松，通常是指死角和洞等难喷涂区域。难喷涂的原因是这些区域的外围吸引了电荷，这样粉末就不能被吸附。另外，从空气动力学来将，输送空气将粉末吹至这些区域也很难。,BackIonisation反弹效应,A=powderattractedtotheearthedcomponentB=builduptocorrectfilmthicknessC=ionisedairwithinthepowderfilmrepelsoncomingparticlesA=粉末吸附在接地工件B=形成合适的膜厚C=在涂层上的离子云抵制吸附带有同类电荷的粉末,PowderRecoveryIntegratedSystem粉末回收系统,IntegratedSpray/RecoveryBoothSystem完整的喷涂/回收系统,PowderRecoverySystems粉末回收系统,Typicalcartridgeback-Pulsecleaningdesign.UsedincartridgeRecoverysystems.典型脉冲自清理设计，通常适用于桶状回收系统,PowderRecoverySystems粉末回收系统,CycloneRecoverySystem,Thecycloneisusedtoseparatethepowderparticlesfromtheair.Theairisdrivenroundthesidesofthecyclone,reducinginvelocityandreleasingthepowdertobecollectedatthebase.Finepowderisusuallytransportedoutofthecycloneontheairflow.旋风分离器根据粒径分离粉末，空气沿着旋风分离器壁做圆周运动，速度渐渐降低，并释放被收集的粉末至底部。细粉通常会随流动空气离开旋风分离器。,PowderRecoverySystems粉末回收系统,Finepowderiscollectedonafiltersysteminthe“afterfilters”.Thepneumaticairpulseensuresairflowisconsistentandthefinepowdercollectedfordisposal.细粉通过滤芯滤层被收集。有力的气体脉冲保证了空气流动的连续性及需被分离的细粉收集。,PowderRecoverySystems粉末回收系统,Amotorgeneratestheairflow.Ensuringthecorrectairvolumeandvelocityismaintained.电机提供流动空气，并保证气体流量和速度。,Powderin-lineSievingSystems粉末过筛系统,RotaryIn-LineSieve旋转筛,PowderVibratingSievingSystems震动筛,Vibratingsievesaredesignedtoworkeither:-Freestanding-In-line震动筛适用于：-独立区域-流水线,PowderReciprocatorCycle粉末喷涂的往复机构,CycleRate往复速度,=,No.OfGunsxPitchofGunsx60喷枪数量x喷枪位置x60,ConveyorSpeed(mm/min)传送链速度（毫米/分钟）,Thiswillensurestriationsdonotoccuronthecomponentsbeingcoated.在喷涂中要保证不要形成带状涂层。,ApplicationPractical实际应用,StovingandCuringofPowderCoatings固化炉及粉末涂料的固化,TypesofOven固化炉的类型,Convectionenergyistransmittedbyaircirculationtoheatthecomponents对流热量通过空气流动传送，加热工件Radiationenergyistransmitteddirectlyontothepartswithoutheatingairbetweenthepartsandtheradiationsource辐射热量直接从辐射源被传送至工件而无需空气作媒体Inductionenergyistransmittedthroughinducingelectricaleddycurrentsthatgenerateheatinthemetalparts感应热量借助电流来传送来加热金属工件,TheBakingProcess固化过程,Thebakingstage,duringwhichthepowdercoatingmelts,flows,gelsandfinallychemicallyreacts(cross-linking)andcures.Itiscriticaltotheperformanceofthecoatingthatthetemperatureandtimeattemperaturearemaintained.Mostbakingovensaredesignedtotakethesubstratethroughapre-programmedtimetemperatureprofile.固化过程包括粉末的熔融，流平，凝胶最后发生化学反应形成涂层。固化温度极其所占时间是非常重要的，大多数固化炉借助预先设置固化时间（温度曲线）来设计。,PowderApplicationRadiationStoving粉末的辐射固化,GasfiresInfra-Redovenusedforindustrialcomponents.左图为用于固化工业用品的瓦斯红外炉,I-Remittersinsidetheovencurethepowderfilmwhenindirectline,asradiationener