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A PRESENTATIONONCAUSES OF BODY COVER(BDC) SCRATCHES IN PAINTSHOPBy: SONU VATS

NECESSITY OF PAINTINGColor and appearanceCovering of gaps between theweld jointsCorrosion resistanceSmoothening of sharp cornersWELD BODYELECTRODEPOSITIONPRETREATMENTUNDER COATINTERMEDIATE COAT (I/C)TOUCH UP AND INSPECTIONPAINT SHOP : FLOWCHARTED OVENSOLSEALINGUNDERCOAT OVENCOOLINGDRY SANDINGI/C OVENCOOLINGDRY SANDINGTOP COAT(T/C)T/C OVENFORASSEMBLYPRETREATMENT PROCESSPRETREATMENT PROCESS :FLOWCHARTHOT WATER RINSESPRAYDEGREASINGDIPDEGREASINGDIP IW RINSEIW RINSEIW RINSESURFACE CONDITIONINGPHOSPHATINGIW RINSEFRESH DI WATER RINSEFOR EDIW RINSEIW RINSEDIP IW RINSEIW RINSEPRETREATMENT STAGESHOT WATER RINSESpray process.Steam injection for heating.Automatic magnetic separator for iron particle removal.OIL REMOVAL BY HOT WATER RINSESTEEL SHEETOIL FILMHOT WATER SPRAYPHYSICAL PRESSURE BY SPRAYING ACT TO LOWER OIL VISCOSITY80-90% OF OIL CAN BE REMOVEDDEGREASING (I)Spray processHeated degreasing chemical solutionOil separator tank for oil separation.De-oiled liquid is recovered to the second degreasing.

DEGREASING(II)Full dipping process using heated degreasing chemical solutionPRETREATMENT STAGESOIL REMOVAL BYDEGREASINGHYDROPHILICRADICALOILPHILIC RADICALSURFACTANTOILPHILIC RADICAL IN THE SURFACTANT DISSOLVES OIL AND LOWERS ITS VISCOSITYSTIRRING POWER TOGETHER WITHANCHORING EFFECT FAVORS TO COLLECT OILOIL SEPARATES FROM THE SURFACESTIRRINGPRETREATMENT STAGESSURFACE CONDITIONINGFull dipping process using Titanium based surface conditioning chemical.Titanium salts form fine colloids which getadsorbed on the metal dipped in surfaceconditioning bath.Function : Adsorbed titanium colloidsprovide fine active nuclei for phosphating reaction.PHOSPHATINGFull dipping process using heated zinc phosphate solution.PRETREATMENT STAGESCleans and provides oil & grease free surfaceFine and crystalline corrosion inhibiting base for ED.Non conducting bond between the substrateand the paint.Chemically inert surface to prevent thereaction between the substrate & the paint ingredients.FUNCTIONS OF PHOSPHATINGPHOSPHATING REACTIONFe + 2H3PO4Fe(H2PO4)2+2H+H2O[O]Sheet metalPhosphating solutionFePO4+ H3PO4 + H2OSLUDGE3Zn(H2PO4)2Phosphating solutionH2OZn3(PO4)2.4H2O + 4H3PO4Coating - hopeiteZn2Fe(PO4)2.4H2O +2H3PO4 +H2OCoating - phosphophylliteSheetmetalPhosphatingsolutionH2O [O]Fe + 2Zn(H2PO4)2P ratio=phosphophyllite (p)phosphophyllite (p) + hopeite (H)PHOSPHATE COATING : QUALITYParametersDip PTSpray PTCOATING APPEARANCEUNIFORM GREY COMPACT FINE COATINGUNIFORM GREY COMPACT FINE COATINGCOATING WEIGHT2.0-3.5 gm/m21.5-2.5 gm/m2P- RATIO> 90%> 80%CRYSTAL SIZE< 10 m< 10 mCRYSTAL SHAPECOLUMNAR CRYSTALSCOLUMNAR CRYSTALSPRETREATMENT STAGES :PROCESS CONDITIONSSTAGEPROCESS TIMEPROCESS TEMPPROCESS PRESSURESPRAY HOT WATER RINSE20 sec50-60 C0.7-1.1 kg/cm2SPRAY DEGREASING50 sec50-60 C1.4-1.8 kg/cm2DIP DEGREASING120 sec50-60 C1.2-1.6 kg/cm2SPRAY WATER RINSE (1)1 riserRT0.7-1.1 kg/cm2SPRAY WATER RINSE (2)15 secRT0.7-1.1 kg/cm2DIP WATER RINSE (3)in/outRT1.2-1.8 kg/cm2SPRAY WATER RINSE (4)15 secRT0.7-1.1 kg/cm2SPRAY WATER RINSE (5)1 riserRT0.7-1.1 kg/cm2SURFACE CONDITIONING (DIP)in/outRT0.4-0.8 kg/cm2PHOSPHATING (DIP)120 sec45 C1.0-1.4 kg/cm2SPRAY WATER RINSE (6)1 riserRT0.8-1.2 kg/cm2SPRAY WATER RINSE (7)15 secRT0.9-1.3 kg/cm2DIP WATER RINSE (8)in/outRT0.9-1.3 kg/cm2FRESH DI WATER RINSE1 riserRT0.8-1.2 kg/m2INDUSTRIAL WATER SPECS.TDSCONDUCTIVITYTOTAL HARDNESSSULPHATESCHLORIDESNITRATESDISS. IRON as FeCHROMIUMCODpH value: 60 mg/L: 100 S/cm: 30.0 mg/L: 5.0 mg/L: 20.0 mg/L: 10.0 mg/L: 0.3 mg/L: 0.05 mg/L: 5.0 mg/L: 7.0 7.5DEIONISED WATER SPECS.pHELECTRICAL CONDUCTIVITY: 6.5 - 7.5: 10 S/cmDRIP WATER CONDUCTIVITY : 50 s/cmTOTAL HARDNESSCHLORIDES AS ClSILICA AS SiO2: NIL: NIL: < 0.4 ppmELECTRODEPOSITIONE-COAT MAIN TANKNO.1 RECOVERED WATER RINSENO.2 RECOVERED WATER RINSENO.3 RECOVERED WATER RINSENO.4 RECOVERED WATER RINSED.I. WATER RINSEFRESH D.I. WATERRINSEFORSOLSEALINGELECTRODEPOSITIONPROCESS : FLOWCHARTEDMainTankDIWater RinseDipZoneSprayZoneDipZoneUltra Filtrate1423SprayZoneELECTRODEPOSITIONPROCESS : FLOW DIAGRAMCu-rod for earthingELECTRODEPOSITION PROCESSED paint dispersed in water is electrically deposited on surface of substrate (body) to form a uniform and water insoluble film.Deposition of film takes place by increase in pH.Paint gets deposited continuously throughconcurrence of four different phenomenon:ELECTROPHORESISELECTRODEPOSITIONELECTROLYSISELECTROSMOSISED PHENOMENONELECTROPHORESIS:Electrically charged substances (dispersed particles, soluble resins) move to the electrodes.Positively charged paint moves to the substrate.

ELECTRODEPOSITION:Insolubilization of resin takes place.Positively charged resin gets deposited on the substrateafter electrical discharging.ED PHENOMENONELECTROLYSIS:Electrolysis of water takes place.Cathode generates H2.

ELECTRO OSMOSIS:Water contained in the film moves against the current of phoresis of resin due to electric potential difference.MECHANISM OF ED+ACOH -RH-NH+

Neutralizer : organic acidO2H+Cathode (substrate) :2 H2O + 2e-2 OH- + H2RNH - + OH-RN+ H2OWATER SOLUBLEWATER INSOLUBLE (DEPOSITED)Anode (electrode) :2 H2O4 H+ + 4 e- + O2E COAT STAGESE-COAT MAIN TANKE-coat paint is deposited onto the substrate.RECOVERED WATER RINSE (I)Spray process using UF permeate liquid.RECOVERED WATER RINSE (II)Spray process using UF permeate liquid.RECOVERED WATER RINSE (III)Full dipping process using UF permeate liquid.RECOVERED WATER RINSE(IV)Spray process using permeate liquidE-COAT STAGESULTRAFILTRATIONMembrane Separation Technology using Pressuredifference method :An appropriate pressure is applied to the solution to be processed.Water and low molecular weight substances suspended in the water pass through the innumerable micropores on the membrane surface.High molecular weight substances and colloidal matter contained in the solution are retained by the membrane.

Advantages:Efficient separation without the aid of heat or any coagulating agent.Properties does not get affected.ADVANTAGES OF ED COATINGCorrosion resistance of car body increases.Paints are deposited even on surfaces inaccessible to conventional methods of painting.Uniform film of desired thickness is obtained easily by adjusting voltage.Quantity of drag-out solids is small since bath paint being diluted with water is low in solid content.ED PROCESSES AND SPECS.STAGEDIP/SPRAYPROCESS TIMEPROCESS TEMPE-COAT MAIN TANKDIP180 SEC26-32NO.1 RECOVERED WATER RINSESPRAY30 SEC26-30NO.2 RECOVERED WATER RINSESPRAY30 SEC26-30NO.3 RECOVERED WATER RINSEDIPIN/OUT26-30NO.4 RECOVERED WATER RINSESPRAY30 SEC26-30NO.1 D.I. WATER RINSESPRAY15 SEC-FRESH D.I. WATER RINSESPRAY1 RISER-STANDARD SPECIFICATIONSED MAIN TANK :Solid content is 16 ~ 20 %Specific conductivity is 1200-1800 S/cmpH is 6.1 + 0.3Paint temperature is 29 + 2CED application voltage is 150-350 VED oven temperature is 180 + 5CPAINT SUPPLY EQUIPMENTN.V.F-1 (PIGMENT) : 56-60 WT% F-2(RESIN) : 35-39 WT%DENSITY(PIGMENT) : 1.45 KG/L(RESIN) : 1.05 KG/LMIX RATIO1:4 + 1E.D. PARAMETERSAnode to cathode ratio1:5 ~ 1:7CathodeBody / SubstrateMain anodesTube typeBottom anodesTube typePAINT TESTINGWET PAINT PROPERTIESDRY FILM PROPERTIESFINENESS OF GRINDINGVISCOSITYSPECIFIC GRAVITY% SOLID CONTENT% BATH SOLIDSSETTLINGFLASH POINTSTORAGE STABILITYCOLOR/SHADEDFT(Outer / Inner)GLOSSHARDNESSADHESIONRa ValueSSTCCTIMPACT RESISTANCEPAINT PROPERTIESPAINT CHARACTERISTICSS. No.CharacteristicInstrument1ViscosityViscosity meter2Particle SizeHegman Gauge3Percentage SolidsOven4Specific Gravity, Wt/10 ltrsWt/10 ltr cup5SettlingResidue Check6Throwing PowerBox Method/Pipe MethodPAINT FILM CHARACTERISTICS:(A) Short term characteristicsS. No.CharacteristicInstrument1GlossGlossometer2HardnessPencil3AdhesionCutter & Cross cut guide5DFT (Outer/Inner)DFT Meter6Impact ResistanceImpact tester7Ra ValueRa MeterPAINT FILM CHARCTERISTICS:(B) Long term characteristicsCharacteristicInstrumentFlexibilityFlexibility testerCorrosion resistance (Humidity Resistance, Salt Spray Resistance, Cyclic Corrosion)Corrosion CabinetCCTCCT CabinetPAINT TECHNOLOGYPAINT INGREDIENTSPIGMENTGives the paint its color and filling properties, undissolved by water or solvent.RESINBinds and wets the pigment giving paint adhesion, gloss, hardness and durability.SOLVENTBinds and wets the pigment giving paint adhesion, gloss, hardness and durability.ADDITIVEImproves paint and paint film properties.THANK YOU