Spray/Dip Pre-treatment
Spray/dip pre-treatment is a crucial process in surface preparation before applying coatings like paint or powder. It involves cleaning, conditioning, and converting the metal surface to ensure optimal adhesion and corrosion resistance of the subsequent coating.
The Process
Both spray and dip pre-treatment involve similar stages but differ in application methods.
Typical stages include:
Degreasing: Removing oils, grease, and other contaminants from the surface.
Alkaline cleaning: Removing rust, scale, and other inorganic matter.
Rinsing: Removing chemicals from the previous stage.
Conversion coating: Forming a protective layer on the metal surface to improve adhesion.
Passivation: Sealing the conversion coating to prevent further oxidation.
Spray pre-treatment:
Chemicals are sprayed onto the workpiece using nozzles. Often used for high-volume production due to efficiency. Requires careful control of spray parameters for even coverage.
Dip pre-treatment:
Workpieces are immersed in chemical tanks. Suitable for complex shapes and large components. Can be slower than spray pre-treatment but ensures complete coverage.
Common Applications
Automotive, Aerospace, Construction, Appliances, Metal furniture