Electrophoretic coating technology is an indispensable part of modern automobile parts manufacturing. The fine control of its process flow is directly related to the quality of the coating and the durability of the product. This article will analyze the process flow of the electrophoretic coating line for automobile parts and explain the key steps and precautions of each link.
Ⅰ. Workpiece preparation and pretreatment
1. Workpiece preparation: The first step of the electrophoretic coating line is to prepare the automobile parts to be coated. Before entering the coating line, these workpieces must undergo strict screening and classification to ensure that they meet the requirements of electrophoretic coating.
2. Pretreatment: Pretreatment is a key link before electrophoretic coating, which aims to improve the adhesion of the coating to the substrate and enhance the corrosion resistance of the coating. The pretreatment steps usually include degreasing, rust removal, phosphating, etc.
Degreasing: Use solvent cleaning or alkaline cleaning to remove oil and impurities on the surface of the workpiece to ensure the surface is clean.
Rust removal: Remove rust and oxide scale on the surface of the workpiece by mechanical grinding, sandblasting or chemical pickling.
Phosphating: A dense phosphating film is formed on the surface of the workpiece to improve the adhesion and corrosion resistance of the coating. The selection of phosphating solution and the control of phosphating time are crucial to the quality of the phosphating film.
Ⅱ. Electrophoretic coating
1. Electrophoretic tank setting: The electrophoretic tank is filled with electrophoretic paint, which contains charged particles. The design of the electrophoretic tank and the selection of paint need to be determined according to the specific material and coating requirements of the workpiece.
2. Electrophoretic coating operation: The pretreated workpiece is immersed in the electrophoretic tank as an anode or cathode. Under the action of the DC electric field, the charged particles move to the surface of the workpiece and deposit under the action of the electric field force to form a uniform and dense coating. During the electrophoresis process, the electric field strength, paint concentration, temperature and other parameters must be strictly controlled to ensure the quality and thickness of the coating.
Ⅲ. Post-electrophoretic treatment
1. Cleaning: After the electrophoretic coating is completed, the workpiece needs to be removed from the electrophoretic tank and cleaned several times. Ultrafiltrate and deionized water are required during the cleaning process to remove the residual paint and other impurities on the surface. During the cleaning process, care should be taken to avoid coating damage or secondary flow marks.
2. Curing: The cleaned workpiece needs to be sent to the curing furnace for baking to make the coating quickly cure and harden. The control of curing temperature and time needs to be determined according to the type of coating and the requirements of the workpiece. The cured coating has excellent durability and corrosion resistance.
Ⅳ. Special processes and precautions
1. Porous and gap parts: For porous and gap parts, a mid-way water blowing process can be added after degreasing to prevent the water in the gaps or holes from affecting the quality of subsequent processes.
2. Electrophoresis parameter control: The voltage, current, time and other parameters in the electrophoresis process need to be strictly controlled to ensure the quality and thickness of the coating. At the same time, the coating composition and pH value in the electrophoresis tank need to be regularly tested to adjust and optimize the electrophoresis process in time.
In summary, the process flow of the electrophoresis line for automotive parts includes multiple links such as workpiece preparation and pretreatment, electrophoresis coating, electrophoresis post-treatment, and special processes and precautions. Each link needs to strictly control parameters and quality requirements to ensure the coating quality and durability of the final product. Attractivechina takes you to explore more knowledge about coating production lines. Please contact us for consultation and get a free quotation!
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