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1 automotive painting process
Introduction
automotive coating process can generally be divided into two parts: First, the metal surface treatment before coating, also known as pre-treatment techniques ; the second is the construction process of painting. Remove the surface treatment include surface of the oil, dust, rust and old paint layer is cleared when the repair work so as to improve the surface state of the workpiece. Including machining and chemical treatment on the surface of various specific circumstances, such as phosphate, oxidation and passivation.
Construction Machinery rustproof coating process is generally divided into surface treatment process before painting and rust primer coating process.
Surface Treatment
Surface treatment is an important step of the rustproof coating. Engineering machinery rust coating quality is good or bad depends largely on the way the surface treatment. According to the British Imperial Chemical Company, coating life terms by 3 factors: surface treatment, accounting for 60 percentage; painting construction, accounting for 25 percentage; the quality of the paint itself, accounted for 15 percentage. Construction machinery industry, surface treatment of different parts. Mechanical cleaning can effectively remove rust, weld slag, oxide scale on the workpiece to eliminate welding stress, increasing the binding force of the anticorrosive coating film and the metal substrate, thus greatly improving the quality of construction machinery parts of rust. Mechanical cleaning standards required to achieve Sa2. 5 grade. To achieve the surface roughness of 1/3 the thickness of the rust-preventive coating. Spray, shot blasting with steel shot to achieve the requirements of GB6484. Surface treatment generally sheet metal member, said surface treatment with a chemical.
process: pre-degreasing rarr; degreasing rarr; rarr hot water; cold water rarr; pickling rarr; cold water rarr; and rarr; cold water rarr; surface conditioning rarr; phosphide rarr; cold water wash rarr; hot water rarr; rarr pure water; dried
The process may also make appropriate adjustments sheet stamping oil, rust, or when no pickling step, with or without pre-degreasing step. Degreasing and phosphate chemical treatment is a key step in the process, the two processes directly affect the quality of the quality and rust-preventive coating chemical treatment of the workpiece. Can not be ignored relevant process parameters and related auxiliary equipment also affect the quality of surface treatment.
Coating process
Due to the wide range of construction machinery, specifications, machine weight, large parts, commonly used for spraying paint. Spraying Tools air spray gun, airless spray gun, air-assisted spray gun and hand-held electrostatic spray gun. Air spray gun low efficiency (about 30 percent), high pressure airless spray gun paint waste, a common feature of both is more serious environmental pollution, and it has been being replaced by portable and air-assisted electrostatic spray gun. The world’s first construction machinery mdash; mdash; mdash; Caterpillar on the use of air-assisted spray gun, and an engine cover for covering the sheet using hand-held electrostatic spray gun. Engineering machinery coating equipment generally use more advanced water rotating spray booth. Small parts can also be used with or without a pump spray booth curtain spray booth, the former has advanced performance, which is affordable, convenient and practical. Because of construction machinery and heavier components, a large heat capacity, thus drying the rust-preventive coating, the general drying method of hot air convection bake evenly. Heat may be adapted to local conditions, the choice of steam, electricity, light diesel oil, natural gas and liquefied petroleum gas.
automotive painting process characteristics and focus
The automotive coating process and the different types of cars have their own characteristics and focus.
primary coating member
is a front portion of a truck cab, painting highest; other components, such as cars, trailers and other requirements of coating is lower than the cab.
truck painting and coating of passenger cars is quite different. Bus body comprising a beam, frame, interior compartment, the outer surface of the body, wherein the outer surface of the body demanding. The outer surface of the body not only requires a good protective and decorative, and spraying large area, multi-plane, there are two or more colors,When there are car ribbon. Therefore, the construction period is longer than trucks, construction requirements higher than the truck, the construction process more complex than the truck.
sedans and station wagons, both relatively high in surface decoration or underlying protection requirements of large passenger cars and trucks. It belongs to a decorative surface coating precision, beautiful appearance, bright as a mirror or smooth surface, no minor impurities, scratches, cracks, wrinkling, blistering and visible defects and should have sufficient Mechanical strength. Belonging to the bottom surface of the coating layer excellent protection, it should be excellent in rust resistance and corrosion resistance, strong adhesion; partially or completely knife good adhesion, high mechanical strength putty, years of use will not be corroded or off and so on.
Coating Equipment
Automatic and manual electrostatic spraying equipment:-through spray, immersion leaching pretreatment device; curtain spray booth; rotating spray booth water; heating, fuel, gas, coal, steam and hot air drying bake drying tank; hanging conveyor, floor conveyor device; the PC electronic control system; Ann sales agent in Japan, Korea KCI host spraying, lifts