ACC specialise in the application of high-performance powder coating to complex components helping customers meet specific engineering performance and visual appearance specifications.
First developed in the 1950s, powder coating is used on an increasing variety of products in almost every major manufacturing industry today.
As demand for greater environmental compliance grows, powder coating is increasingly the preferred finishing process over traditional solvent-based wet paints, as they contain no solvents and emit negligible, if any, polluting VOCs (volatile organic compounds) into the atmosphere.
ACC provide specialist powder coating application services to components in the automotive, defence, marine, offshore, rail sectors and general industrial sectors.
The powder coating process includes surface pre-treatment, powder application (automatic and manual) and high-temperature oven curing
Powder coatings are available in a range of differing chemistries to suit specific product application requirements
Benefits provided by powder coatings include corrosion resistance, cosmetic enhancement and enhanced functional performance
Applications include high temperature, noise reduction, vibration damping, anti-graffiti and anti-bacterial
Available in a wide range of colours, texture, gloss levels and can also be manufactured to custom colour matches
To understand why powder coating is more advantageous than wet paint, it’s important to first understand the process. Powder coating is the electrostatic application of organic powder to metal parts requiring protective or decorative coating. The powder is cured by heating or baking, resulting in a hard, continuous coating.
The powder coat process includes pre-treatment, powder application and high-temperature powder curing. The process begins with pre-treatment/surface preparation of the substrate. Each part is cleaned, removing grease, dirt and anything else that might interfere with the painting process. This may include abrasive/mechanical or chemical cleaning, though it usually consists simply of cleaning the metal surface and pre-treating it in some fashion (e.g. phosphating) to prepare the surface to bond well with the powder during the curing process that follows as well as providing a degree of corrosion resistance. Without proper pre-treatment, the powder on a part will chip and corrode easily.
Following pre-treatment, the object must be completely dried before powder is applied. This can be accomplished using oven drying or air drying. If an oven is used for the drying process, the part usually must be cooled before the application of powder coating. Once completely dry, the part is ready to have powder applied using either spray techniques. The powder is electrically charged as it is applied to the part, giving each particle of the powder a negative charge. The part being powder coated is electrically grounded as a means of attracting and attaching the powder to the part’s surface. This electrostatic attraction is a key requirement of the process, aiding the coating evenness and the speed of applying the coating. The result is a uniform coating of dry powder clinging to the part. After the part is coated with powder, it is moved into a conveyorised curing oven. There the powder gels, flows and cures to produce a smooth, durable powder coat finish.
Wet painting is a traditional treatment method by which a pigment in any water-based or solvent-based paint is sprayed onto the surface of a part. Common applications of wet paint include automotive exteriors and extremely large or heavy items. When superior performance is required, powder coating as a finishing process can replace traditional wet painting.
Many concerns or issues associated with wet paint finishing are eliminated or minimised with the powder coating process. The advantages of powder coating over wet paint are many, and they generally fall under four categories.
Powder coatings are more durable and more resistant to corrosion, chemicals and weather than liquid coatings. Powder-coated surfaces are more resistant to chipping, scratching and other such wear due to the thermal bonding process during curing. Unlike wet paint, powders also don’t run or drip, providing a more uniform coating than liquid paint. The result of using powder coating is that the product will have the most attractive, durable, high-quality finish available.
Powder coatings are cheaper and can cover more area than most other organic finishes, translating to lower material costs than wet painting processes. Because they lend themselves well to automation, powder coatings can also reduce costs related to operational labour, as reduced operator training and supervision are required for a powder line. Compared to wet paint processes, operational cost savings using powder coatings can also be realized in greater throughput, less waste produced, lower energy costs, reduced disposal costs and less rework due to lower reject rates.
Wet paints can be flammable, carcinogenic and full of volatile organic compounds (VOCs). These chemicals can be hazardous to plant/shop personnel if not handled properly. Powder coatings, on the other hand, are generally VOC-free materials and contain no solvents, meaning they do not involve the potentially harmful chemicals typically found in a wet spray project. Although powder coating materials can combust in a very narrow concentration of powder and air, their lack of solvents or VOCs means almost none of the short-term and long-term health or fire workplace threats associated with wet painting.
VOCs in the wet painting process are also among industrial pollution concerns. Because powder coatings contain no solvents and emit negligible, if any, polluting VOCs into the atmosphere, they are more environmentally friendly than their wet paint counterparts. Moreover, powder coating is a clean process: powder overspray can be retrieved and reused, and unused powder can be reclaimed and returned to a hopper for recirculation through the system, with negligible waste. Plus, most powder coating materials are considered landfill/non-hazardous materials. Powder coatings meet all Environmental Protection Agency requirements for air and water pollution control.