阿克苏粉末涂料的应用

Powder ApplicationProcessContentPretreatmentPowder ApplicationCuringPretreatmentContentMechanical Pretreatment ( ) Chemical PretreatmentMechanical Pretreatment ( )( )Shot Blasting /MetalPolishMetalNon-metal MDF( )Shot Blasting/-Shot blasting, with spherical grit (S coded)-S -Grit blasting, with angular grit (G coded)-GShot Blasting/Coating adhesion :•Efficiency :Shot blasting < grit blasting•Shot blasting: Grease on the surface could be inserted into the metal by impact.•Steel or stainless steel grit recommended•Corundum accepted rather for non ferrous metalsMechanical pretreatment -Blast cleaning type to use //Grit blasting key points –The initial condition of the parts -Degrees of rust before preparationNorm ISO 8501-1 1998 or Swedish SIS 05.09.00defines 4 initial rust degrees, degree C is generally the highest accepted degree before grit blasting)A BC D /CD•Cleanliness: Free from dirt, contamination, impurities, oil or grease.•Dry parts: must be perfectly dry before grit blasting-to blow them with compressed air-stove them some minutes recommendationGrit blasting key points -The initial condition of the parts -Shot Blasting/•Grits are clean from impurities•The compressed air equipment is dry and free from greaseDesoiling deviceAir dewatering device•Degree of air humidity < 85%85% (ISO 8502-4)•Substrate > 3°C above dew point3o C (ISO 8502-4)Grit blasting key points -Application condition –/Two Indicators:-Roughness profile-Cleanliness levelFinal grit blasting results/CLA:Average line. Peaks area is equal to troughs area Ra:Average peak size (excluding troughs)Rt : Distance between the highest peak and the lowest troughRz:It is the average of the Rtmeasures on 5 lengths Roughness ParametersFinal grit blasting results : Roughness profile/The roughness can be:-Measured with a roughness measurement device recommendation Final grit blasting results : Roughness profile-Estimated with a roughness comparator(ISO 8503 comparator, or the Rugotest n°3 LCA-CEA in accordance with NFE 05051 1981 standard)/The roughness specification depends on the coating thicknessFilm thickness Rt x 2Rt = Ra x 7.2 Rt 14 RaRoughness specification to request: ISO 8503ISO 8503 Rz=40~75umRa=6~12umFinal grit blasting results:Roughness specification/Final grit blasting results:Cleanliness profile ISO 8501-1 Sa2.5Sa 3Sa 1Sa 2Sa 2.5 /Sa 2.5Remove steel dust by blowing•Use brush or compressed air blow ensures also the removal of grit particles can check by tape•The parts must not be soiled : handle with glovesFinal grit blasting results:The dust removal ISO 8502-3 < 2 /Mechanical Pretreatment( )PolishMetalNon-metal MDFMetal•A most simply pretreatment not recommendation•For re-coating process•The paper must finer than 180mesh180•Blow out the dust with compressed air•Non-metal MDF •The paper must more finer than 280 mesh 280•Blow out the dust with compressed air•Pre-heat•55~70o C when spray55~75o C•Surface humidity 6~9%6~9%Chemical PretreatmentVariety of Chemical Pretreatment•Solvent not recommendation) •Phosphate•Iron•Zinc•Manganese•Chromate•6+ chromate•3+ chromate•Non-chromate•Ultrasonic for Bronze and polish metalVariety of Method•Dipping•Complex Substrate •Tube•Spray•Simple Substrate•PlateStandard ProcessDegreaseRinseRinseEtch /RinseConversionRinseRinseDe-ionised water DryControl of Chemical PretreatmentCleaner ConcentrationEtching Concentration and etching weightPH of Rinse PHConversion Concentration and coating weightConductivity of Final RinseObservationsChecked at regular intervals during normalproduction and before production commences,recommend once 4 hours4Recommendation of different SubstrateIron/Steel/CastIronALCast ALDie-cast AlAlloyMgMDFCoatingWeightStandardShot BlastingISO 8501-1ISO8502-3ISO8502-4ISO 8503 PolishZinc-Phosphate1~2g/m2ISO 9717GB/T11376DIN EN12476 Iron-Phosphate0.2~1g/m2Mn-PhosphateChromate/Non-Chromate/0.2~2g/m2ISO 10546ASTMB449-93DIN EN12487Powder ApplicationPowder Application SystemsPowder Fluidisation SystemsDry air passes through amembrane giving the powderliquid qualities.The air must be dry and freefrom water and oil.Check Powder FluidizationForces at work on the Powder Particles At any one time 4 forces areat work on the powderparticle as it travels from thegun to the earthed work-piece.4-Air Resistance-ElectrostaticAttraction-Weight (Gravity)-Aerodynamic ForcePowder Charging SystemsThere are 2 major categories in charging of powder coatingcorona and tribo:— /Gun Type Charge LocationInternal ExternalRemotePowder Supply X X CoronaIntegrated GunPowder Supply X X TriboXCorona Charging SystemsIn this method, a high voltage generator is used to charge an electrode at the tip which creates an electrostatic field (or corona) between the gun and the work-piece.External Charging System/Corona Charging SystemsCorona charging-Manual system/-Automatic system/Corona Nozzle SystemsThe type of product toBe coated will influenceThe nozzle to be used ontheSpray gun, two types are shownTribo Charging SystemsTribo electricity is generated by the friction of one material on another.In Tribo charged spray guns, the powder rubs on a specially formulated and shaped surface which allows charge to transfer.Tribo Charging SystemsTribo nozzles in different configurations.CoronaTriboFaraday Cage Difficult to apply inside faradayareasEasier in faraday areasControl Film Build 1.difficult to apply more than250 um due to backionization ,250um2.Window effect1.Can apply wherehigh film build isrequired2.Homogeneous filmChemistry Will apply most all chemistriesand formulationMay require specialformulationEfficiency FastSlowPattern Control inautomatic gun Done with varying sizes of tipsIndividual nozzles can bepointed into difficult tocoat areasCorona vs TriboElectrostatic Fluid Bed SystemsPowder Recovery SystemsCyclone Recovery SystemThe cyclone is used toseparate the powder particles from the air.The air is driven round the sides of the cyclone, reducing in velocity and releasing the powder to be collected at the base.Fine powder is usuallytransported out of the cyclone on the air flow.Powder Recovery SystemsFine powder is collected on a filter system in the “after filters”. The pneumatic airpulse ensures air flow is consistent and the fine powder collected for disposal.Powder Recovery SystemsA motor generates the airflow. Ensuring the correct airvolumeand velocity is maintained.Powder in-line Sieving SystemsRotary In-Line SievePowder Vibrating Sieving SystemsVibrating sievesare designed towork either:-Free standing-In-line--Powder Reciprocator CycleCycle Rate =No. Of Guns x Pitch of Guns x 60x x60Conveyor Speed (mm/min)/This will ensure striations do not occur on the components being coated.。