The powder coating process has become increasingly popular in the recent years. It is now one of the foremost and widely used processes for providing dry finish to automotive and other industries. As a consequence, you get a long-lasting, corrosion-resistant surface with a smooth finish.
What is Powder Coating?
The powder coating process is basically a dry finish procedure that has grown in popularity in North America ever since its inception in the 1960s. The powder is used on a range of items, accounting for about 15% of the whole commercial finishing industry. Powder coatings are increasingly being specified for a high-quality, long-lasting finish. This enables higher production, increased efficiency, and improved compliance with environmental regulations. Powder coatings are present in quite a variety of colours and patterns, and technological improvements have led to exceptional performance attributes. They are used in utilitarian (protective) and aesthetic finishing.
Electrostatic spray deposition (ESD) and fluidised bed application are the two most common powder coating processes. Both processes can give a consistent, hard surface coating that is more durable, cost-effective, and ecologically friendly than a liquid coating. Powder coatings have certain other benefits over liquid coatings, particularly in heavy or high-traffic surfaces. The application area, substrate elements, sizing, pricing, processing times, and other factors decide the sort of coating technique most appropriate for any material.
Powder Coating Process
In comparison to the liquid coating method, which uses coating in solution form, powder coating uses dry powder. The powder is sprayed on a prepared substrate and then exposed to temperature ranging from 180°C to 220°C for 10-30 minutes. The melted powder then solidifies forming protective covering over the substrate.
The entire application involves three steps:
1. Pre-Treatment
The base must be thoroughly cleaned to eliminate all dirt, grease, oils, and other contaminants. Depending upon the substrate type, suitable chemical pre-treatment method is followed. For mild steel, either seven tank zinc phosphating or iron phosphating is used, recent trend is to use tricationic or nano cationic coating. For aluminium substrate, zinc chromating is an ideal method of pre-treatment. While in the case of heavy casting components, where two coat system is to be applied, sand blasting or grit blasting is the preferred method of surface preparation.
2. Application
The substance is suitable to be coated once it has been processed. Powder coating process, similar to liquid paints, involves spraying the powder onto the surface with a gun. Powder coating, unlike liquid coatings, depends on the electromagnetic charge. The powder is charged in the gun either electrically or by friction. Whereas, the substrate is grounded, delivering it the opposite charge as of the powder inside the gun. Since opposite charges attract each other, the powder will be pulled to the substrate as it comes out of the gun in turn thoroughly covering it.
The substrates like wood, plastic, etc., cannot be grounded, they can only be powder coated with specialised application technique.
3.Curing
The substrate is typically heated to temperature ranging from 160° to 230°C for anything from ten minutes to even more than an hour throughout the heat treatment. Beyond this criteria, the shape and size of the substrate may impact the temperature and time required for curing powder coating process. A convection oven, an infrared oven, or a hybrid oven that incorporates both kinds is used to heat the materials.
What is RoHS Compliance?
RoHS is an abbreviation for Restriction of Hazardous Substances. RoHS, also referred to as Directive 2011/62/EU, is a European Union directive that prohibits the use of certain hazardous compounds in electrical and electronic equipment.
With rare exceptions, products complying with this regulation do not include more than the permissible levels of the prohibited materials like lead, mercury, cadmium, hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE).
Grand Polycoats is one of India’s top industrial paint and powder coating manufacturers, specialising in high performance protective paints and coatings using polyurethane, epoxy”, zinc rich, acid resistant, heat resistant, and special polymers. Based on the industry and requirement, we provide technologically advanced solutions that suits your need and are highly durable.
GP Envirocoat, our powder coating brand, offers variety of products that are RoHS compliant. As powder coating is economical on pockets, environmental friendly, has faster turnaround time and emits zero VOC, it is the preferred choice in selection of the paint system.
The different types of Powder coatings offered by Grand Polycoats are:
- Epoxy
- Pure Polyester (PP)
- Epoxy Polyester (Hybrid)
- Heat Resistant
- Two coat system – Primer & Topcoat
- Low Bake – Energy Efficient
We hope this blog was helpful in getting to know the basics of Powder Coating process. If you have any questions or need assistance in choosing the right system, please reach out to us at marketing@grandpolycoats.com.