粉末噴涂與應用

粉末噴涂與應用第1頁/共72頁MetalPreparation金屬的處理Pretreatmentisaprocessintendedtopreventthecorrosionofthepaintedmetal.前處理是一種提高耐腐蝕的工藝Fe2+O2+H2O = RUSTIronreactswithoxygenandwaterintheatmospherecreatingapowderybrownmess,notveryornamental,andcontinuousuntilnosolidmetalremains.鐵在空氣中會與氧氣和水反應生成褐色的物質第2頁/共72頁MetalPreparation金屬處理Severalmethodsofcorrosionpreventioncanbeused幾種防腐蝕的方法ForSteel:鐵：Automotiveapplications汽車業(yè)Primer:Underseals:LayersofPaint.

第3頁/共72頁Severalmethodsofcorrosionpreventioncanbeused幾種防腐蝕的方法ForSteel:鐵：ArchitecturalApplications建筑業(yè)Galvanising:AntiCorrosivePrimer*Galvanising–coveringwithalayerofzinc.MetalPreparation金屬處理第4頁/共72頁MetalPreparation金屬處理第5頁/共72頁MetalPreparation金屬處理Severalmethodsofcorrosionpreventioncanbeused幾種防腐蝕的方法ForAluminium:鋁：Aluminiumoxidisestoformawhitecorrosionproduct鋁被氧化后形成白色的物質ArchitecturalApplications

建筑業(yè)Anodise:AcidPrimers第6頁/共72頁MetalPreparation金屬處理WhyPretreatment?為什么要前處理？Powdercoatingsareusedtoenhancetheappearanceofbuildings,machines,furniture,appliances:粉末涂料用于改善建筑，機械設備，家具，以及其它器具的表面：Designersandarchitectsaresearchingtogivedistinctionintermsofcolourandeffects.設計師和建筑師提供了包括顏色和效果在內的標準等級Theproblemisthatallpaintsareporous：所有的涂料均不同程度的存在會滲水的小孔第7頁/共72頁MetalPreparation金屬處理Moleculesofwaterandsaltcanpenetratethroughthepaintfilm.Whentheyreachthemetalsurfacetheeffectisworsethanifthemetalisuncoated.Theanswer=Pretreatment水和鹽分子可以滲透漆膜，一旦它們與金屬表面接觸，產生的影響甚至比沒有噴涂還要糟糕。要解決這個問題就需要前處理。第8頁/共72頁MetalPreparation金屬處理Pretreatment:前處理Thechemicalconversionofthemetalsurfacebeforeapplyingthepowdercoating.Themetalthenresistscorrosionandtheconversion

permanentlyimprovestheadhesionofthecoating.在使用粉末涂料以前用化學方法對金屬表面進行處理，可以改善耐腐蝕性和增加涂層的附著力。第9頁/共72頁MetalPreparation金屬處理Theperformanceofthepowdercoatingisonlygoingtobeasgoodasthemetalpreparation.Wewillcoverthreetypesofmetaltreatmentsystems粉末涂料的功能類似于金屬處理，我們將介紹三種的金屬處理方法IronPhosphateforSteel用于鐵系的磷酸鐵ZincPhosphateforSteel用于鐵系的磷酸鋅ChromateforAluminium用于鋁的鉻酸鹽Othersystemscanbeusedandinformationisavailable.當然還有其它處理方法第10頁/共72頁MetalPreparation–IronPhosphate金屬處理—磷酸鐵Metalpretreatmentcanbeappliedbysprayordipping.金屬前處理可以借助噴淋或浸漬Inthecaseofironphosphatetheprocesscouldlooklikethis:下面是磷酸鐵的工藝流程Stages1,2and3canbeeithersprayordip步驟1，2和3均可采用噴淋或浸漬DRAINDRAINStage1Clean&PhosphateStage2RinseStage3Rinse&SealWorkFlow第11頁/共72頁MetalPreparation–IronPhosphate金屬處理—磷酸鐵Typical3StageSystem典型的3步驟流程MetalSubstrate Steel–PhosphatisingSystem金屬基材

NoneFerrous–CleanandEtchStagetimeduration 1–90seconds不同步驟所需的時間 2–45seconds 3–30secondsStagetemperature

1，2和3步驟所需的溫度 40–60oCDrying/干燥溫度 100–120oCTypicalconcentration 2–3%byvolume典型的濃度

Typicalacidity典型的酸值

pH3.5–5.5Typicalcoatingweight 典型的膜重 20–40mg/ft.第12頁/共72頁MetalPreparation–ZincPhosphate金屬處理–磷酸鋅ZincPhosphateprocessforsteeltendstobemorecomplicated磷酸鋅的工藝流程復雜一些Stage1CleanStage2RinseStage3Phos-phateStage4RinseStage5RinseDRAINDRAINDRAINDRAIN第13頁/共72頁MetalPreparation金屬處理DwellTime:Eachstagedependson:各階段所需的時間，受下面的因素控制

Theamountofpretreatmentchemicaldissolvedinwater溶于水的前處理化學藥品的濃度

Theageofthechemical化學藥品的有效時間Regularcheckingisrequiredtogiveconsistentgoodresults–atleasttwicepershift.通常要經常檢查前處理的狀態(tài)—一個班至少兩次第14頁/共72頁MetalPreparation–ZincPhosphate金屬處理–磷酸鋅Typical5StageSystem典型5步驟流程MetalSubstrate Steel–PhosphatisingSystem金屬基材

NoneFerrous–CleanandEtchStagetimeduration 1–90seconds不同步驟所需的時間 2–45seconds 3–60seconds 4–30seconds 5–30secondsStagetemperature溫度 40–60oCDrying干燥溫度 100–120oCTypicalconcentration典型濃度 2–4%byvolumeTypicalacidity 1=alkaline酸堿性 2=acidicTypicalcoatingweight

40–70mg/ft.典型的膜重第15頁/共72頁MetalPretreatment-BS3189Type3SprayPhosphatePlant9stagepretreatment九步法

Degrease脫脂

Rinse水洗

Rinse水洗

Rinse水洗AcidEtch(phosphoricacid)表調ZincPhosphate磷酸鋅磷化

Rinse水洗

Rinse水洗

De-ionisedwater去離子水水洗

Dry干燥QualityStandard

BS6497參考英國標準BS6497第16頁/共72頁MetalPretreatment

–QualityControl金屬前處理–質量控制TitrationChecks:檢測項目：

1.Cleaner 2.Rinses 3.AcidConcentration 4.Rinse 5.PhosphateConcentrationandcoatingweight 7.Rinse 8.ObservationsCheckedatregularintervalsduringnormalproductionandbeforeproductioncommences以上項目應在生產過程中定時和生產前進行檢驗第17頁/共72頁MetalPretreatmentDry金屬前處理干燥Toensuremetalsurfaceisdryreadyforpowdercoating.在噴涂粉末涂料前必須保證金屬工件已經完全干燥Dryingoven-PhosphatePlant第18頁/共72頁MetalPreparation–Chromate金屬處理—鉻酸鹽Foraluminium–chromateconversion鋁—鉻酸鹽處理BritishStandardsexistfortheconversionofaluminium–

BS6496適用于鋁的英國標準BS6496ThesameconversioncanbeusedforGalvanisedsteel--BS6497適用于電鍍鐵的英國標準BS6497Stage1CleanStage2RinseStage3EtchStage4RinseStage5Chrom-ateStage6–7RinseStage8DeminRinseDRAINDRAINDRAINDRAINDRAINDRAIN第19頁/共72頁MetalPreparation–Chromate金屬處理—鉻酸鹽Typical7StageSystem七步法MetalSubstrate Aluminium/AluminiumAlloys金屬基材

GalvanisedSteel–CleanandEtchStage1 CleaningStage2 RinseStage3 DeoxidisemetalsurfaceStage4 RinseStage5 ChromateStage6 RinseStage7 AcidulatedRinseStageTemperature 80–100oCDrying 90–95oCDonotoverheatatthedryoffstage干燥溫度不能過高第20頁/共72頁MetalPreparation–Chromate金屬處理—鉻酸鹽ChromateconversiontoAluminiumandGalvanisedsteel鉻酸鹽處理完鋁和電鍍鐵后的變化YellowChromateConversion TypicalCoating黃色鉻酸鹽的變化 Weight(g/m2)PaleYellow 0.2–0.7Gold 0.7–1.6Brown 1.6–3.5Greenmixchromate/phosphate 0.5–2.0

ForPowderCoatingalightweightcoatingisrecommendedIntherange0.2–2.0g/m2應用于粉末涂料，膜重一般在0.2—2.0g/m2第21頁/共72頁SprayingandApplicationofPowderCoatings粉末涂料的噴涂與應用第22頁/共72頁第23頁/共72頁第24頁/共72頁PowderApplicationSystems粉末涂料的應用系統(tǒng)第25頁/共72頁PowderApplicationSystems

FeedSystems粉末涂料應用系統(tǒng)供粉系統(tǒng)DirectfeedsystemfromDrumtoGun.粉末涂料直接從粉桶送至噴槍Thesystemshownfeeds1gun右圖是只供一個噴槍的直接供粉系統(tǒng)第26頁/共72頁PowderApplicationSystems

FeedSystems粉末涂料應用系統(tǒng)供粉系統(tǒng)Directfeedsystemdirectlyfroma25kilobox.Thissystemissetuptofeed2guns.Usedmainlyinmanualoperations.右圖為直接從粉末涂料的包裝箱至噴槍的供粉系統(tǒng)。圖中的設備適用于兩把噴槍，通常用于人工噴涂。第27頁/共72頁PowderApplicationSystems

FeedSystems粉末涂料應用系統(tǒng)供粉系統(tǒng)Bulkfeedsystem,powderissuppliedinafibrebag.Weightofpowder–upto1,000kilosperbag.Usedmainlyonautomaticplantswherecolourchangeislimited.大型供粉系統(tǒng)，粉末涂料一般1噸一個包裝，用于自動噴涂系統(tǒng)，限于換色較少的場合。第28頁/共72頁PowderFluidisationSystems粉末涂料流化系統(tǒng)Dryairpassesthroughamembranegivingthepowderliquidqualities.干燥的空氣通過微孔板，使粉末涂料象水一樣流動。Theairmustbedryandfreefromwaterandoil.空氣必須除水和油第29頁/共72頁PowderDeliverySystems粉末涂料的傳送系統(tǒng)第30頁/共72頁PowderDeliverySystems粉末涂料的傳送系統(tǒng)ActualpowderfeedsystemVenturifeedfromfluidbed.右圖是用文氏管從流化床吸取粉末的送粉系統(tǒng)第31頁/共72頁ForcesatworkonthePowderParticlesAtanyonetime4forcesareatworkonthepowderparticleasittravelsfromtheguntotheearthedwork-piece.粉末在離開噴槍到達工件時受4種力的影響AirResistanceElectrostatic AttractionWeight(Gravity)AerodynamicForce第32頁/共72頁PowderChargingSystemsThereare2majorcategoriesinchargingofpowdercoatingcoronaandtribo:粉末涂料主要有兩種帶電方法—靜電/摩擦GunType ChargeLocation充電位置 Internal External Remote PowderSupply X XCorona靜電法

IntegratedGun PowderSupply X XTribo 摩擦帶電法

X第33頁/共72頁CoronaChargingSystems靜電帶電系統(tǒng)Inthismethod,ahighvoltagegeneratorisusedtochargeanelectrodeatthetipwhichcreatesanelectrostaticfield(orcorona)betweenthegunandthework-piece.利用高壓電極使粉末帶電，并在噴槍與工件間形成電場ExternalChargingSystem/外充電系統(tǒng)第34頁/共72頁CoronaChargingSystems靜電帶電系統(tǒng)Coronacharging -manualsystem/手動槍

-automaticsystem/自動槍第35頁/共72頁CoronaChargingSystems靜電帶電系統(tǒng)InternalChargingSystem內充電系統(tǒng)第36頁/共72頁CoronaNozzleSystems靜電槍的噴嘴ThetypeofproducttoBecoatedwillinfluenceThenozzletobeusedontheSpraygun,twotypesareshown第37頁/共72頁CoronaNozzleSystems靜電槍的噴嘴ConicalSprayNozzles–usedtogiveanevenlydistributedfilmthicknessoverflatpanels.圓錐型的噴嘴一般用于噴涂平面，并得到膜厚均勻的涂層。InterponAFparticlemanagedpowderbeingappliedondomesticappliances.右圖為InterponAF粉末涂料用于家用設備第38頁/共72頁CoronaChargingSystems靜電帶電法Thehighvoltagepowersupplychargestheelectrode高壓發(fā)生器使噴槍電極帶電Theconcentratedchargecreatesanelectrostaticfield帶上電荷后形成靜電場Theelectrostaticfieldcausestheairtoionizeandgenerateacorona靜電場使空氣電離形成電暈Thecoronaemitselectrons電暈放射出電子Theelectronsarepickedupbyoxygenmoleculesformingnegativeions這些電子借助氧分子形成負離子第39頁/共72頁CoronaChargingSystems–cont.靜電帶電法Theionsfollowthefieldlines負離子沿著電力線移動Thepowderparticlesdistortthefieldaroundthem粉末涂料粒子使周圍的電力線產生扭曲Thedistortedfieldlinesdirectionstothepowderparticles扭曲后的電力線引導離子被粉末涂料粒子吸附

Theionsbombardthepowderparticlesandtransfertheelectronsgivingtheparticlesanegativecharge吸附的離子轟擊粉末粒子，并使其帶上負電，形成負極第40頁/共72頁TriboChargingSystems摩擦帶電法Triboelectricityisgeneratedbythefrictionofonematerialonanother.InTribochargedsprayguns,thepowderrubsonaspeciallyformulatedandshapedsurfacewhichallowschargetotransfer.摩擦帶電是通過不同物質摩擦形成的，摩擦槍可以使粉末與特殊設計并有特殊結構的表面摩擦而帶電第41頁/共72頁TriboChargingSystems摩擦帶電法第42頁/共72頁TriboChargingSystems摩擦帶電法Tribonozzlesindifferentconfigurations.不同結構的摩擦槍噴嘴第43頁/共72頁ElectrostaticFluidBedSystems靜電流化床法第44頁/共72頁PowderPenetration粉末的吸附Thepictureshowsthedevelopmentofthecorona(reddottedarea).Articlespassingthrougharechargedwiththenegativeions(-).Thechargedpowderparticlesareattractedtotheearthedsubstrate.右圖顯示了電場，電力線，粉末的充電及被接地的工件吸附過程。第45頁/共72頁PowderPenetration粉末的穿透Achievingpenetrationintodeeprecessesinmostimportantwhenapplyingpowdercoating.粉末涂料能否到達死角這對粉末涂料的應用來說很重要ThemosteffectivecontrolsarethenozzlepatternAndairassistance.有效的控制方法是選擇合適外形的噴嘴及調整輔助空氣Itispossibletoovercomethe“FaradayCageEffect”現在，克服“法拉第”效應已成為一種可能第46頁/共72頁PowderPenetration粉末的穿透Reducingthe“FaradayCage”Effect減弱“法拉第”效應ToreducetheeffectitisnecessaryToassistinthecreationofchargedairParticlesinsidetherecess.Thisshouldbe徹achievedbyincreasingtheairstream.可以借助加大傳送空氣的壓力來減弱“法拉第”效應第47頁/共72頁FaradayCageEffect“法拉第”效應

AFaradaycagecantechnicallybedefinedasanareawithinwhichthereisnoelectrostaticfield. Infinishing,thistermisappliedmoreloosely,andgenerallyreferstoanareasuchasinsidecornersorcavitiesthataredifficulttocoat. Thereasonwhytheseareasaredifficulttocoatisthattheadjacentsurfacestotheinsideofthecornerattracttheelectrostaticfiled,thereforedeflectingthepowderfrompenetratingintotherecessedareas. Atthesametime,thisrecessedareaisdifficultfortheaerodynamicforcestopenetrateintowithoutblowingpowderoffalreadycoatedareas.

法拉第區(qū)域可以被認為是靜電屏蔽區(qū)。實際應用中定義更寬松，通常是指死角和洞等難噴涂區(qū)域。難噴涂的原因是這些區(qū)域的外圍吸引了電荷，這樣粉末就不能被吸附。另外，從空氣動力學來將，輸送空氣將粉末吹至這些區(qū)域也很難。第48頁/共72頁BackIonisation反彈效應A=powderattractedtotheearthedcomponentB=builduptocorrectfilmthicknessC=ionisedairwithinthepowderfilmrepelsoncomingparticles

A=粉末吸附在接地工件B=形成合適的膜厚C=在涂層上的離子云抵制吸附帶有同類電荷的粉末第49頁/共72頁PowderRecoveryIntegratedSystem粉末回收系統(tǒng)IntegratedSpray/RecoveryBoothSystem完整的噴涂/回收系統(tǒng)第50頁/共72頁PowderRecoverySystems粉末回收系統(tǒng)Typicalcartridgeback-Pulsecleaningdesign.UsedincartridgeRecoverysystems.典型脈沖自清理設計，通常適用于桶狀回收系統(tǒng)第51頁/共72頁PowderRecoverySystems粉末回收系統(tǒng)CycloneRecoverySystemThecycloneisusedtoseparatethepowderparticlesfromtheair.Theairisdrivenroundthesidesofthecyclone,reducinginvelocityandreleasingthepowdertobecollectedatthebase.Finepowderisusuallytransportedoutofthecycloneontheairflow.旋風分離器根據粒徑分離粉末，空氣沿著旋風分離器壁做圓周運動，速度漸漸降低，并釋放被收集的粉末至底部。細粉通常會隨流動空氣離開旋風分離器。第52頁/共72頁PowderRecoverySystems粉末回收系統(tǒng)Finepowderiscollectedonafiltersysteminthe“afterfilters”.Thepneumaticairpulseensuresairflowisconsistentandthefinepowdercollectedfordisposal.細粉通過濾芯濾層被收集。有力的氣體脈沖保證了空氣流動的連續(xù)性及需被分離的細粉收集。

第53頁/共72頁PowderRecoverySystems粉末回收系統(tǒng)Amotorgeneratestheairflow.Ensuringthecorrectairvolumeandvelocityismaintained.電機提供流動空氣，并保證氣體流量和速度。第54頁/共72頁Powderin-lineSievingSystems粉末過篩系統(tǒng)RotaryIn-LineSieve旋轉篩第55頁/共72頁PowderVibratingSievingSystems震動篩Vibratingsievesaredesignedtoworkeither: -Freestanding -In-line震動篩適用于： -獨立區(qū)域 -流水線第56頁/共72頁PowderReciprocatorCycle粉末噴涂的往復機構CycleRate往復速度=No.OfGunsxPitchofGunsx60噴槍數量x噴槍位置x60ConveyorSpeed(mm/min)傳送鏈速度（毫米/分鐘）Thiswillensurestriationsdonotoccuronthecomponentsbeingcoated.在噴涂中要保證不要形成帶狀涂層。第57頁/共72頁ApplicationPractical實際應用第58頁/共72頁StovingandCuringofPowderCoatings固化爐及粉末涂料的固化第59頁/共72頁TypesofOven固化爐的類型Convection–energyistransmittedbyaircirculationtoheatthecomponents對流–熱量通過空氣流動傳送，加熱工件Radiation–energyistransmitteddirectlyontothepartswithoutheatingairbetweenthepartsandtheradiationsource輻射–熱量直接從輻射源被傳送至工件而無需空氣作媒體Induction–energyistransmittedthroughinducingelectricaleddycurrentsthatgenerateheatinthemetalparts感應–熱量借助電流來傳送來加熱金屬工件第60頁/共72頁TheBakingProcess固化過程Thebakingstage,duringwhichthepowdercoatingmelts,flows,gelsandfinallychemicallyreacts(cross-linking)andcures.Itiscriticaltotheperformanceofthecoatingthatthetemperatureandtimeattemperaturearemaintained.Mostbakingovensaredesignedtotakethesubstratethroughapre-programmedtime–temperatureprofile.固化過程包括粉末的熔融，流平，凝膠最后發(fā)生化學反應形成涂層。固化溫度極其所占時間是非常重要的，大多數固化爐借助預先設置固化時間（溫度曲線）來設計。第61頁/共72頁PowderApplicationRadiationStoving粉末的輻射固化GasfiresInfra-Redovenusedforindustrialcomponents.左圖為用于固化工業(yè)用品的瓦斯紅外爐I-Remittersinsidetheovencurethepowderfilmwhenindirectline,asradiationenergy.右圖為通過爐內紅外發(fā)生器（熱源）固化粉末涂料I-Risoftenusedtoboostthecuringinfrontofaconventionalaircir