Powder coating is one of the most popular forms of surface finishing for the high quality diecastings which we produce at MRT. The process involves spraying coloured dry powder, a mixture of pigment and resin, from a highly controllable gun towards the intended surface. The powder and part-to-be-coated are oppositely electrostatically charged, making them attracted to each other. This charge results in the powder sticking to the surface, in a very even layer that is thicker than most traditional paint applications. The nature of the powder coating process and application means that the coating gets applied evenly and into all the hard to reach areas.
The powder coated part is then placed into an oven to cure. The polymer resin within the powder begins to adhere with heat on the surface of the part, resulting in a thick coating that is incredibly durable compared to other surface finishes.
WHY POWDER COATING IS A SUPERIOR FINISH
Powder coating, unlike paint, is a combination of pigment compound (for colour), filler material (for a smooth surface) and resin (that melts and fuses everything together). This results in a surface finish with an incredibly durable, polymer-like finish, yet is smooth and shiny like paint.
On top of its more durable finish when compared to paint, powder coating is also more efficient in a number of different ways.
Firstly, powder coating contains no solvents, liquid elements or VOCs (Volatile Organic Compounds) and makes the process more environmentally friendly than other finishing processes. The process is completely dry and solvent free resulting in a process that doesn’t need expensive fume extraction or pollution control systems.
Whilst roughly 50% of spray paint is wasted during regular painting processes due to overspray and extraction, powder coating has a much higher rate of transfer to the ‘paint’ surface. This results in a more efficient painting process. In addition, any overspray can easily be collected and recycled for use again.
Finally, the powder coating process is much simpler and more forgiving when compared to traditional painting techniques. There’s no chance of too much spray causing ‘drips’ or ‘runs’ in the finish of the paint and very little chance of a spotty or streaky finish if not applied correctly.
These benefits add up to a more durable finish that is both better on the environment and more cost effective for a number of applications.
MRT works with a number of specialist powder coating partners who have extensive experience in coating aluminium diecastings. MRT manage the entire supply chain, offering you a one-stop-shop rather than dealing with a sequence of individual sub-contractors yourselves.
WHAT CAN BE POWDER COATED?
Powder coating can be applied to range of different materials and manufacture types including casted, forged or billet aluminium, steel and iron. Any material that can be electrostatically charged can be powder coated.
WHEN SHOULD POWDER COATING BE USED?
Powder coating is the perfect finishing method for when a part needs a solid and durable finish, resistant to impact and abrasion.
Powder coating can be done in a any colour, and number of different finishes from gloss, metallic, flat, pearlescent etc. Powder coating can even come with special properties such as anti-bacterial for medical applications, or anti-graffiti for outdoor use.
However, powder coating does have its limitations. The thick coating that makes it so durable, makes it difficult to use on parts that require tight tolerances. Areas of the part can be masked off to preserve the manufactured dimensions (similar to paint), but this is a labour intensive process and increases costs.
Powder coating is, without doubt, one of the best finishing processes for casted metal parts available on the market. It yields a high quality yet durable finish that protects the parts from abrasion, corrosion and impact, with a wide variety of colour and finish options.
If you’re currently designing a new cast part and would like to find a single source supplier to manage the entire project, from casting through to powder coating then contact MRT Castings today.
