Electrostatic Powder Coating, In this method of application, a high voltage generator is used to charge an electrode at the tip of the powder gun.
This creates an electrostatic field (or corona) between the gun and the substrate. Gas molecules in the air pick up electrons emitted from the corona.
This negative charge is, in turn, transferred to the powder particles as they are propelled from the gun head towards the substrate. The charged powder particles are deposited on the earthed substrate.
How Powder Coating Works
Powder coatings are based on polymer resin systems, combined with curatives, pigments, leveling agents, flow modifiers, and other additives. These ingredients are melt mixed, cooled, and ground into a uniform powder similar to baking flour. A process called electrostatic spray deposition (ESD) is typically used to achieve the application of the powder coating to a metal substrate. This application method uses a spray gun, which applies an electrostatic charge to the powder particles, which are then attracted to the grounded part. After application of the powder coating, the parts enter a curing oven where, with the addition of heat, the coating chemically reacts to produce long molecular chains, resulting in high cross-link density. These molecular chains are very resistant to breakdown. This type of application is the most common method of applying powders. Powder coatings can also be applied to non-metallic substrates such as plastics and medium density fiberboard (MDF).
Sometimes a powder coating is applied during a fluidized bed application. Preheated parts are dipped in a hopper of fluidizing powder and the coating melts, and flows out on the part. Post cure may be needed depending on the mass and temperature of the part and the type of powder used. No matter which application process is utilized, powder coatings are easy to use, environmentally friendly, cost effective, and tough!
Durability of Powder Coating
Powder coating is a high-quality finish found on thousands of products you come in contact with each day. Powder coating protects the roughest, toughest machinery as well as the household items you depend on daily. It provides a more durable finish than liquid paints can offer, while still providing an attractive finish. Powder coated products are more resistant to diminished coating quality as a result of impact, moisture, chemicals, ultraviolet light, and other extreme weather conditions. In turn, this reduces the risk of scratches, chipping, abrasions, corrosion, fading, and other wear issues.
It's tough. It looks great. And it lasts a long, long time. In addition to being durable, powder coating is an attractive choice due to environmental advantages.
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