Ever wondered how metals can be electrically insulated? This is a result of powder coating, where free-flowing, dry powder is applied on metal surfaces to act as electrical insulators. It also serves to make surfaces abrasion-resistant, protecting the underlying layer of metal with the outer coating of powder. The coating is usually applied via electrostatic processing and cured under high heat. These powder coating systems have become an essential aspect of the production line in many industries, but how did we arrive at this stage of electrostatic processing? Here is a summary of the history of powder coating systems, and how technology has brought us this far.
1. Concerns about liquid finishings and their solvent contamination led to a need for a new method of applying coatings on metals. This resulted in the concept of utilising organic polymers in powder forms, where they would be flame-sprayed onto metallic substrates.
2. A more efficient alternative to flame-spraying was soon designed by Dr. Ewrin Gemmer, a German scientist, as stated by Paint and Coatings Industry. The fluidized bed application was developed for quick functional powder coating, in order to produce corrosion- and abrasion-resistant surfaces. It gained traction and was deployed on almost all powder coating applications.
3. During this period, the electrostatic processing of powder coating was commercialized and rose in popularity. It employed electrostatic spray guns to add a fine coat of polymer powder to the desired surface as if the powder were liquid in nature. Electrostatic attraction between the surface and the charged powder particles resulted in the latter sticking to the former. This layer of powder coating melted and fused with the ground layer in conventional bake ovens.
Now, electrostatic processing has become the most common powder coating technique in the world and is applied in almost all powder coating systems. Technology has compounded its efficiency with the increased effectiveness in spraying methods and formulation of new powders. But perhaps twenty years in the future, the current powder coating systems will become things of the past. Still, electrostatic processing is a critical aspect of any production process, and powder coating systems should never truly become obsolete, only improved upon.
