What is a powder sprayer?

A powder sprayer is a device that applies a protective coating to metal parts with a finish similar to traditional liquid paint. The main difference between the two methods is the method of application of the coating. In the case of powder spraying, a stream of positively charged powder is applied to a grounded or negatively charged metal surface. Compared to conventional paints, this electrostatic method results in better metal-bonding coatings and offers other advantages that liquid paints cannot provide. There are usually several different powder sprayer types, the most common being the variants of corona and friction spray guns.

Powder coating is the process of coating a metal item with a layer of powdered thermoplastic or thermoset polymer. This method is an effective and efficient method for coating a wide range of consumer products from household appliances to garden furniture. These finishes are available on several different powder sprayer types, including spray, electrostatic disc, electrostatic magnetic brush, and fluidized bed systems. Of these, the spray type is the most widely used in most commercial applications. Corona and friction sprayers are used the most.

A corona gun powder sprayer consists of a powder distributor, a high voltage generator, a corona gun with a powder feed hose and a negative or ground connection. To operate the corona gun system, secure the ground connection to the workpiece and load a suitable powder coating into the machine's dispenser. A high-voltage generator energizes the electrodes in the gun, imparting a strong positive charge in the powder and creating a high-energy electric field between the powder and the workpiece. This electric field acts as a stimulator that attracts the positively charged powder to the workpiece surface. Upon contact, the powder coating bonds to the metal surface, creating a uniform layer.

Friction powder sprayers also rely on an electric field to bond the powder to the metal surface, but use compressed air to transport it through a Teflon® tube and nozzle towards the workpiece. The positive charge in the powder is imparted by friction between the powder and the surface of the Teflon® tube and binds the powder layer to the metal in the same way as the corona gun method. After coating with both systems, the workpiece is typically heated to spread the plastic coating more evenly and complete the bonding and curing process.