Everything starts with cleaning. Oil, grease, oxide and weld residue are removed from the surface, because powder won't adhere to a dirty surface no matter how well it's sprayed.
Pre-treatment comes next — a conversion coating that boosts corrosion resistance and gives the powder a chemically consistent base to bond to.
The part is then hung on the line and sprayed. The gun charges the powder as it leaves the nozzle; the grounded part attracts the powder and holds it in place until curing.
In the oven, the film is brought up to the temperature specified by the powder manufacturer and held there long enough to fully cure. Under-baking leaves a soft, weak film; over-baking can shift the colour.
Finally, the batch is inspected: film thickness is measured, adhesion and surface quality are checked, and the RAL code with gloss level is logged so a repeat order can be matched exactly.