Liquid Coating Line Process and Core Equipment Systems

A liquid coating line is a highly integrated industrial system designed to deliver various, consistent, and high-quality surface finishing. With the growing advancement of automation and intelligent manufacturing, modern coating lines are now widely applied across industries such as metal fabrication, automotive parts, aluminum profiles, home appliances, and industrial equipment.

5 Core Processes of Liquid Coating Line

A complete coating production line typically consists of five main processes, each playing a critical role in final coating quality:

1. Pretreatment System

Pretreatment prepares the workpiece surface before coating.

• Metal parts: removal of oxides and formation of conversion layers

• Plastic parts: oil removal and surface cleaning

This stage significantly improves coating adhesion and corrosion resistance, extending the service life of the finished product.

2. Primer Coating

The primer layer seals the substrate, enhances corrosion protection, and improves adhesion between the base material and the topcoat. Stable circulation and filtration systems ensure consistent coating quality throughout production.

3. Topcoat Coating

The topcoat provides the final decorative appearance and primary surface protection. As the thickest coating layer, it enhances color consistency, weather resistance, and aging performance.

4. Clear Coat (Varnish) Coating

The clear coat improves gloss, color depth, and resistance to environmental damage. Modern wet or dry spray booths, integrated with robotic spraying systems, serve as the core spraying units in coating workshops.

5. Curing & Drying System

Each coating layer must be cured after spraying. Advanced curing ovens combine infrared heating, hot air circulation, and energy recovery technologies, ensuring excellent coating performance while reducing energy consumption.

Core Equipment Systems Supporting the Liquid Coating Line

A modern Liquid Coating Line is built on nine core equipment systems, including:

• Pretreatment systems

• Spray booths and workstations

• Robotic spraying systems

• Conveying systems (Power & Free, AGV, RGV)

• VOCs exhaust gas treatment systems

• Intelligent control systems

• Curing ovens

• Utility systems

• Equipment operation & maintenance support

Together, these systems form a complete, automated, and environmentally compliant coating production solution, meeting today’s strict quality and sustainability requirements.