How To Use Thermoplastic Powder Coatings
The using method of thermoplastic powder coatings mainly include:
- Electrostatic spraying
- Fluidized bed process
- Flame Spray technology
The basic principle of this process is that the electrostatic powder is guided to the surface of the metal workpiece under the combined action of compressed air and electric field when passing through the gap between the spray gun and the grounded metal workpiece.
The charged powder adheres to the surface of the grounded metal workpiece, then is melted in an oven and cooled to obtain a high-quality coating.The particle size is strictly chosen between 150-200µm.
Fluidized Bed process
This process requires a powder container with an air pressure regulator.The compressed air is evenly dispersed throughout the container with the help of the porous membrane at the bottom of the container, making the plastic powder boil like a liquid
When the thermoplastic powder in this fluidized bed comes into contact with the preheated metal workpiece, the powder close to it adheres to its surface and melts. The metal is then lifted and cooled to form a high-quality coating.
Both finer and coarser particles are suitable for this process.
Flame Spray technology
The thermoplastic powder is fluidized by compressed air and fed into the flame gun. The powder is then injected through the flame at high speed. The residence time of the powder in the flame is short but sufficient to completely melt the powder particles. Molten particles in the form of highly viscous droplets are deposited on the substrate, forming a thick film upon solidification.
This technique is used for objects that cannot be heated or that do not fit in an industrial oven.
The other using method of thermoplastic powder coatings have rotary lining process .