Powder coating is applied using two main methods: electrostatic spray deposition (ESD) and fluidised bed powder coating. With the ESD method, powder is sprayed electrostatically onto a substrate. The substrate is grounded, and an electrostatic spray gun imparts a charge to the powder, causing it to adhere to the surface. The powder is then cured in an oven where it melts, flows, and bonds to the substrate, creating a durable coating. Electrostatic spray systems often include a spray booth for overspray containment and powder recovery.
In the fluidised bed method, the substrate is preheated, and then dipped into a fluidised bed of suspended powder. The heat causes the powder to adhere to the substrate, forming a coating. An alternative, electrostatic fluidised bed method charges the powder particles in the bed, enhancing adhesion. Once coated, the parts are cured in an oven, where the powder particles fuse into a continuous film. Before application, the substrate must be thoroughly cleaned and prepared to ensure proper adhesion. Common preparation steps include cleaning, etching, and blasting, using equipment like wash stations and blast rooms. If certain areas of the substrate need to remain uncoated, masking materials are applied. The curing process for both methods typically takes place in a powder-curing oven, where the coating solidifies into a strong, cohesive finish.
