Powder Coating

Powder coating is a dry paint application method that involves applying a charged polymer powder to a metal product. The powder is attracted to the grounded material through electrostatic charge. Subsequently, heat is applied to cure the powder, resulting in a durable and seamless finish.

One of the key advantages of powder coating is the absence of liquid components, eliminating the need for solvents and reducing the production of hazardous chemicals. Additionally, the electrostatic curing process ensures that the paint does not sag or run, enabling the application of thicker and more robust coatings.

The most efficient way to powder coat large volumes of parts is by utilizing a comprehensive paint line. This motorised track system allows unfinished parts to be securely attached, typically by hanging. The track guides the parts through each stage of the powder coating process until they reach the end of the line, where the finished parts are then removed.

By using a paint line, the powder coating process becomes highly streamlined, enabling continuous movement of parts from one stage to the next. This efficient method ensures consistent and uniform coating application, resulting in high-quality finished products.

As the paint track moves, the hung parts pass through various specific stages which ensure the final quality of the paint finish:

Stage one – Pre-treatment

The parts undergo a thorough cleaning process to ensure their optimal condition. Initially, a highly alkaline cleaner is applied to effectively remove any manufacturing residue and dirt. Subsequently, the parts are rinsed with both mains water and demineralized water to ensure complete cleansing.

To provide a protective barrier against corrosion, a saline-based liquid pre-treatment known as Oxsilan 9810 is applied. This pre-treatment relies on chemical bonding to enhance the parts’ resistance to corrosion. Following the application of Oxsilan 9810, the parts undergo a final rinse with demineralized water, ensuring the removal of any remaining residue.

By following this meticulous cleaning and pre-treatment process, the parts are prepared to meet the highest standards of quality and durability.

Stage two – drying

After the pre-treatment process, the prepared parts are carefully transferred to an oven set at approximately 180 degrees Celsius. This controlled temperature environment allows the parts to undergo a thorough drying process, ensuring they are fully prepared to receive the epoxy paint powder.

By subjecting the parts to the optimal drying temperature, any remaining moisture is effectively eliminated, promoting excellent adhesion and overall paint finish quality. This crucial step sets the stage for the subsequent application of the epoxy paint powder, ensuring optimal results in the powder coating process.

Stage three – powder application

Once the pre-treated parts are securely mounted on the track, the automated process takes them through the spray booth. Inside the booth, electrostatic spray guns come into action, applying the charged powder to the parts. The electrostatic charge ensures that the powder particles are attracted to and evenly coat the grounded parts, creating a uniform paint layer.

To ensure comprehensive coverage, the parts then proceed to another area where skilled operators equipped with manual electrostatic spray guns meticulously cover any intricate or hard-to-reach areas. This additional step guarantees that all surfaces of the parts receive a consistent and thorough coating of the powder, leaving no areas untouched.

By combining automated and manual application techniques, we achieve a high-quality finish on every part, ensuring complete coverage and a visually appealing appearance.

Stage four – stoving

To complete the powder coating process, the coated parts are conveyed through a gas-fired tunnel oven. The oven is set to a specific temperature depending on the type of powder used. As the parts travel through the oven, they are exposed to the critical temperature at which the powder begins to melt and flow.

During this melting and flowing stage, the powder particles bond together, forming a durable and smooth finish on the parts. The heat of the oven ensures that the powder fully cures, resulting in a resilient coating that adheres securely to the surface of the metal.

Once the parts have gone through the curing process in the tunnel oven, they are fully coated and the paint has reached its final state, ready for use or further processing. This curing step is crucial in achieving a robust, long-lasting finish that enhances the appearance and durability of the parts.

Powder coating is available in any colour including metallic finishes such as gold or silver. At Alpha Manufacturing, we offer a standard range of colours and all else are available on request.

Other finishes such as plating or EPD (electrophoretic dip coating) are also available.

Powder coated finishes are known for their exceptional durability compared to other paint finishes, as they offer superior resistance to chipping, scratching, fading, and general wear. This enhanced durability is attributed to the thicker coating and the strong chemical bonding that takes place during the curing process.

At DC Manufacturing, we go the extra mile by applying a high-quality pre-treatment called Oxylan 9810. This pre-treatment significantly enhances the corrosion resistance of the powder coated parts, making them ideal for use in demanding outdoor environments. In fact, we can confidently guarantee a 1000-hour salt spray protection for our powder coated products, ensuring their long-lasting performance and appearance.

With our advanced powder coating process and reliable pre-treatment, you can trust DC Manufacturing to provide superior protection and quality for your products, even in challenging conditions.

While powder coating offers the advantage of a thicker finish compared to wet spray, there are instances where a customer may require a thinner paint, which can be a limitation of powder coating. Achieving a finish thinner than 25 microns with powder coating can be challenging. At DC Manufacturing, we understand this requirement and offer a wet spray finishing service for customers seeking a thinner paint application.

One drawback of powder coating is the time it takes to change colors. To address this issue, we have implemented “quick color change” booths, which significantly improve changeover times, minimizing downtime and increasing efficiency.

It’s important to note that while a wide range of powder coated colours is available, on-site mixing to create different shades is not possible. At DC Manufacturing, we maintain a stock of standard colours, and any specific colours beyond our standard range can be requested.

If you have any questions regarding powder coating or any other sheet metal processes, please don’t hesitate to contact us. We’re here to assist you with your inquiries and provide the best solutions for your needs.