What is powder coating of metal parts?
Powder coating is a continuous, aerodynamic process in which dry powder particles are applied to the metal surface using an electrostatic fluidised bed system. The charged powder particles adhere to the object due to an electric field generated between two electrodes located directly above and below the bed.
The quality of the workpiece is determined by the surface finish, texture, appearance, dimensional stability, adhesion to the substrate and chemical resistance. These factors can be modified over time to achieve optimum performance for a particular application. Powder coating improves the life of the product or saves costs compared to conventional painting processes.
How are the steel parts treated before the powder coating is applied?
It is important to clean the surface to achieve maximum adhesion to the substrate. To remove grease, oil, dirt, dust and rust, it is washed with an acidic or alkaline cleaner. It is then dried with compressed air or with the help of blowers.
This cleaning process ensures that the powder adheres better to the surface, as there are no impurities that could prevent adhesion. In this way, we achieve good results even if the metal parts are already old (i.e. rusty).
How is the powder coating applied?
The thickness of the applied powder coating depends on the specific application and the surface morphology of the substrate. The dry particles are charged by an electric field, which releases them from the container and assists their flight to the metal parts to be coated. The powder particles fall vertically downwards under gravity at a speed of 30 m/s until they adhere to the surface of the object, forming thin layers with exceptional adhesion to the substrate that are very resistant at high temperatures. This process can be repeated several times to achieve a higher quality and, if required, a greater layer thickness.
Is an oven used after powder coating?
The powder coating is cured in high-temperature ovens that reach up to 300 °C. The duration of the heating cycle depends on the thickness of the applied powder and its specifications (from 5 to 20 minutes). After cooling, the parts are finally ready for use.
What types of metal parts can be treated with powder coating?
Originally it was used for iron or steel, but today this Technology for a wide range of metals such as steel, aluminium, copper, stainless steel, etc. All these objects can be powder coated: Car bodies, bicycle frames, furniture parts, metal tools or any other object that you want to protect from rust or corrosion.
Powder coating offers a number of advantages over liquid paints
The mechanical properties of powder coating are superior to those of conventional paint systems. These include chemical resistance, adhesion and hardness.
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