In the process of powder painting or powder coating of metallic workpieces, metal surfaces and coating powder are electrostatically charged in a magnetic field. The powder applied is then baked into the surfaces at a high temperature of 180-200 degrees. In this way, the paint powder and metal interact to create a highly durable painted surface.
The fact that electrostatic powder coating is nowadays an indispensable and also ecological process is illustrated by the fact that 98 % of the applied coating material actually bonds with the metal. When blown onto the surface, the paint particles are charged with a very low direct current of 0.7 mA and applied to the earthed workpiece.
The process involves the following steps:
1) Degreasing, iron phosphating and spray rinsing
2) Drying in the natural gas-powered drying oven at 120 degrees Celsius
3) Applying the paint in an automatic or manual powder coating booth with cyclone
4) Painting of samples in a manual booth
5) Baking in a natural gas-fired baking oven at 180 degrees Celsius
6) 150-metre monorail conveyor with loading and unloading areas
7) Control panels with PLC control
The plant consists of an automatic, continuous monorail conveyor system with automatic lubrication and the areas as specified above. Depending on the chemicals used to degrease and phosphate coat the items to be painted and on whether the powder coating is for exterior or interior use, a corrosion resistance in the salt spray test of between 300 and 500 hours can be achieved.
The plant is operated at a conveyor belt speed of between 0.5 and 1.2 metres/minute, allowing an area of up to 1500 square metres to be painted in 2-shift operation.