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The electrostatic application of powder coating to a part begins with fluidization. Fluidization is a process where powder being sprayed mixes with compressed air, enabling it to be pumped from a container and supplied to the spray guns. The powder flow is regulated by controlling the air supplied to the pump. The powder supplied to the spray gun is charged using either a corona or tribocharging gun. Charged powder moves to the grounded workpiece with the help of air supplied to the guns and the airflow in the booth.
When the powder particles come close to the part, an electrostatic attraction between the charged powder particles and the grounded part adheres powder to the part.
The coated part then passes through an oven and is cured. The oversprayed powder is contained within an enclosure and drawn into the primary filter cartridges by a centrifugal fan. Circulating air, now free of powder, is discharged through high-efficiency final filters into the plant as clean air. The primary filter cartridges are periodically reverse-pulsed to remove oversprayed powder. The powder is then sieved and supplied back to the guns to provide extremely efficient material for use again. A simple diagram showing how this process works is shown in Figure 1 below.