Our pre-treatment and electrocoating line (E-coat line) conducts surface treatments to the body-in-white (BIW), including degreasing, phosphating/silanizing, and electrocoating, to form a uniform and dense anti-corrosion layer. Comprising two main systems of pre-treatment and cathodic E-coating, the line utilizes a combined spray and dip process, supported by integrated systems for temperature control, filtration, ultrafiltration, pure water supply, and automatic chemical dosing, ensuring process stability. The entire pre-treatment and electrocoating system features a fully enclosed design for centralized treatment of waste gas and liquid, meeting stringent environmental standards.

Phosphating Pre-treatment Process
Pretreatment prepares the metal: degreasing saponifies and emulsifies oils, multi-stage rinsing eliminates chemical residues, surface conditioning enhances the surface, and phosphating develops a fine, uniform crystalline layer that improves paint adhesion and corrosion resistance.

Green Pre-treatment Process (Silane-based)
Serving as a foundation for electrocoating, the green pre-treatment process features core stages include degreasing, multi-stage rinsing, pure water rinsing, and silane film formation. This process effectively removes oil and impurities from metal substrates, generating a uniform and dense silane conversion coating. Compared to traditional phosphating, it offers significant advantages: residue-free operation, no need for pickling, environmental friendliness, a thin and uniform film, and broad applicability to various sheet metals. This greatly improves the adhesion of subsequent electrocoating layers and the substrate's corrosion resistance.

Electrocoating Process (Cathodic E-coating)
Our electrocoating process utilizes cathodic E-coating. The coating formation during this process involves four key chemical and physical mechanisms: electrophoresis, electrodeposition, electrolysis, and electroosmosis.

• Electrophoresis: Positively charged paint particles migrate towards the cathode (the workpiece).
• Electrodeposition: Forms a uniform wet film with inherent self-limiting properties as charged particles deposit onto the surface.
• Electrolysis: Creates an alkaline environment on the workpiece surface.
• Electroosmosis: Causes dehydration of the coating, making it dense, which enhances hardness and adhesion.