What is the powder coating process?

 No matter what infrastructure you work in, whether it’s healthcare, manufacturing, construction, or agriculture, powder coating can offer a number of advantages over regular paint. Due to its application process, powder coating gives a finish that provides greater weather resilience, improved gloss and matte retention, increased humidity resistance, better protection against UV rays, and superb hardness.

 It’s no wonder then that global demand for powder coatings was valued at $7.5 billion in 2014 and is expected to reach $11 billion in 2020. Let’s dive in and take a deeper look at the process behind the highly desirable properties of powder coating.

 The powder coating process

The powder coating process is very similar to a painting process, except that the ‘paint’ is a dry powder rather than a liquid. The process can be broken down into three key stages

•  Preparation
• Powder coating application    
• Curing

 However, depending on the material that requires powder coating, the preparation process can differ significantly.

 Preparation

To achieve the best possible finish, the surface has to be properly prepared. This entirely depends on the base material being powder coated. Generally speaking, any grease, oil, or oxides need to be removed from the surface. These all decrease the potential surface area for powder coating to stick.

 After cleaning, etching, and rinsing, the surface is neutralised in a chemical solution. Once again, the chemical solution is different depending on the surface material and should be formulated to work with it specifically. These chemicals form an important part of the process, as they allow the powder to stick to the surface. Finally, before the coat application, the surface is demineralised. This removes any chemical salts on the surface that stops corrosion occurring underneath the powder coating, which would damage it.

 Powder coating application

The application process isn’t possible without four key pieces of equipment:

      ●     Powder feeder

●     Power unit

●     Electrostatic gun

●     Powder booth recovery system

To start, the spray gun supplies the powder from the feeder unit onto the prepared surface. The powder feeder continuously gives a flow of powder to the guns. The thickness is controlled via the independent control of powder and air volumes, giving the technician the ability to adjust dilution ratios.

 After application, the powder can adhere to the workpiece for several hours. This occurs thanks to the electrostatic charging of the powder and grounding of the parts. Equally, it’s simple to start the process again if any problems occur during application - the unheated powder is simply vacuumed off and applied again.

Curing

Once the coat is applied and complete surface coverage checks are completed, the surface material is placed in a convection oven at a minimum of 160 degrees Celsius. This is the most energy-intensive section of the entire process for one major reason - the whole part must be hot enough to cause the part surface to either dry or the powder coat to cure.

 For smaller parts, this isn’t such a problem as hot air can heat the parts relatively quickly. For large and heavy materials being powder coated, it can be slow and costly. Large volumes of air need to be heated and exhausted from the convection oven to effectively dry or cure the parts.

 The advantages of the powder coating process

The entire powder coating process results in an aesthetic, durable, and resilient surface finish that does a much better job at withstanding the challenges of your industry than traditional paint. Even better, the level of thickness is customisable and can meet standards of protection for harsh environments and specific industry demands.

 The surface gives the object or material better humidity resistance, hardness, gloss, and matte retention, and even protection against UV radiation. All things considered, powder coating is a viable way to finish and protect surfaces from small parts to steel structures.

 At Tomburn, we protect the integrity of your powder coating through accurate and effective pre-treatment services. We specialise in the pre-treatment of aluminium, mild and galvanised steel, zintec, and ferrous and non-ferrous castings. If you want more information about our pre-treatment and powder coating services, or you need a quote, get in touch with us simply by calling 02392 692 020.