As a critical stage in the powder coating process, the pretreatment line exhibits the following six key characteristics:

• First, Thorough Cleaning:
  Processes such as ultrasonic degreasing, high-pressure rinsing, or laser derusting ensure complete removal of oil, rust, and other contaminants from the workpiece surface, providing a clean foundation for coating.

• Second, Surface Conversion:
  Treatments like phosphating or passivation form a micro-porous protective film on the metal surface, enhancing corrosion resistance and creating "anchor points" for coating adhesion, increasing bond strength by over 40%.

• Third, Stringent Drying:
  Utilizing hot air circulation drying at 80-120°C with strict temperature and time control ensures thorough drying. The workpiece must proceed to powder coating within one hour to prevent residual moisture from causing defects like pinholes or blistering.

• Fourth, Systematic Process:
  The entire pretreatment involves multiple interconnected stages (e.g., degreasing, rinsing, phosphating), requiring precise parameter control to ensure overall quality.

• Fifth, Environmental Adaptability:
  Increasing adoption of green technologies such as chromium-free passivation and phosphating solution recycling reduces pollutant emissions, meeting increasingly stringent environmental standards.

• Lastly, Adaptability to Complex Shapes:
  Methods like combined spray-immersion, multi-angle spraying, or rotating nozzles ensure uniform and effective treatment of all surfaces, including internal areas, corners, and blind holes of complex workpieces.