Color Powder Coating
What is Color Powder Coating?
Powder is a dry coating. Instead of being dissolved or suspended in a liquid medium, such as solvent or water, powder is applied in a granular form. This material is finer than ground pepper but coarser than flour, and is applied directly to the surface to be coated.
How is Color Powder Coating Applied?
The application process involves applying an electrostatic charge to the dry powder particles and spraying them onto a grounded substrate. The substrate, or part, is typically grounded through the conveyor or hanger holding the part. The powder, once attracted to the part, is then held on the surface until it is melted and cured into a smooth coating film in the bake oven. The spray process takes place inside a booth designed to contain the oversprayed powder and makes it possible to collect the overspray and ultimately reclaim it for reuse.
The powder is fed pneumatically out of the color powder coating container, or hopper, into the powder applicator, or gun. As the powder exits the gun, a low amperage, high voltage charge is applied to the powder particles, causing them to be attracted to the grounded workpiece. This attraction may even cause the powder to "wrap" around the piece, coating the back side.
The oversprayed powder, suspended in the air contained inside the powder booth, is then passed through a separation process that permits the powder particles to be retrieved from the air. The clean air is fed back to the work environment, eliminating the need for air make-up. The reclaimed powder is mixed with a proportionate amount of fresh, virgin powder for reuse achieving consistent results and up to 98% material utilization.
Color powder coating systems are available in all degrees of technical sophistication, and can be designed to meet a wide range of requirements for performance, cost and space constraints.
From a basic manual, one gun operation with a batch booth, to a highly complex multi gun, totally automated configuration, there are guns, booths and other peripherals for all occasions.
The guns are all essentially similar in their function of spraying the powder. Each gun has a control unit that regulates the voltage being generated and the rate at which the powder is delivered from the hopper. Areas to review when selecting the application equipment are the efficiency of the charge, the consistency of the powder flow, and the accuracy with which both can be adjusted to provide the right level of performance. Once the optimal settings have been established it is important that they can be repeated systematically each time they are used.