What is the Process of Powder Coating | Everything You Need to Know About Powder Coating | CNCLATHING

For completing the powder coating, the essentials, powder gun, powder, compressor, regulator, oven, air filter and the part could all be required. Powder coating process has three stages, starting from preparation, go through the application, then to the curing stage. How does the powder coating process work?

1. Preparation of powder coating

There is a lot of preparation work to do before applying the coating. The purpose of preparation is to make the material be suitable to be coated. If there are oils, solvent and other residues adhere to the surface of the substrate, remove them with weak alkali and neutral detergents in dip tanks, or spraying the object with hot water, steam, detergent, and other solutions, to ensure the surface of the parts to be coated is completely clean. If the surface of the part with remaining debris like rust, scaling, and existing paint that difficult to clean, a blast room is required, it using pressurized fluid to propel abrasive material, such as sand, grit, or shot, against the surface, to achieve a smoother surface. Otherwise, the quality of the surface finish will be affected. In some cases, a certain area of the part needs to be exposed, masking products should be used to prevent the area from being coated.  

2. Application

How to apply the powder coating paint? Two methods using different coating materials are commonly employed by finishing services supplier. 

– Electrostatic spray deposition (ESD): used on most metal parts, the electrostatic spray coating consisting of depositing electrically charged powder particles is applied on the metal surface through a powder spray booth, powder feeder, or electrostatic spray gun. 

– Fluidized bed powder coating: in the process of fluidized bed application, preheated parts will be dipped into the powder material within a fluidized bed, another operation is applying the electrostatic fluidized bed powder coating, which generates a cloud of electrically charged powder particles above the fluidized bed through which the part is coated. 

3. Curing stage

The characteristics of the curing stage are mainly affected by which powder coating method used. The machined parts coated with electrostatic spray deposition need to be cured in a powder curing oven, as the coated parts reach the optimal curing temperature in the oven, the powder particles melt and flow together, thus forming a continuous film on the surface of the parts. Parts in different sizes takes a different amount of time to complete the process. The parts coated with a fluidized bed can be heated and cured in a curing oven after it has been coated, like with coatings produced by the ESD method.