The working principle of the electrostatic powder spray […]
The working principle of the electrostatic powder spraying method is almost the same as that of the general liquid coating electrostatic spraying method. The difference is that the powder spraying is dispersed instead of atomized. It is the paint sprayed by the electrostatic powder spray gun, which makes the powder particles negatively charged while dispersing. The charged powder particles are affected by the air flow (or centrifugal force and other forces) and electrostatic attraction to apply to the grounded coating. On the object, it is heated to melt and solidify to form a film. Let's take a look at the process flow of electrostatic powder spraying.
The process flow of electrostatic powder spraying:
1. Pre-treatment, purpose: to remove oil, dust, and rust on the surface of the workpiece, and form a layer of "phosphate layer" or "chromium layer" on the surface of the workpiece that is anti-corrosive and can increase the adhesion of the spray coating. Main process steps: degreasing, derusting, phosphating (chromizing), passivation.
2. Electrostatic spraying, purpose: spray powder coating evenly on the surface of the workpiece. Special workpieces (including positions that are prone to electrostatic shielding) should be sprayed with a high-performance electrostatic spraying machine. Process steps: Using the principle of electrostatic adsorption, a layer of powder coating is evenly sprayed on the surface of the workpiece; the fallen powder is recovered through the recycling system.
3. Curing, purpose: to solidify the sprayed powder on the surface of the workpiece. Process steps: Put the sprayed workpiece in a high temperature furnace of about 200°C for 20 minutes (the curing temperature and time depend on the quality of the selected powder, and the curing temperature of the special low temperature powder is about 160°C, which saves more energy). Melt, level, and solidify.
The above is the process flow of electrostatic powder spraying. Electrostatic powder spraying can reduce the degree of environmental pollution and has significant economic benefits.