[China Aluminum Network] friction gun due to the higher efficiency of the powder, for a variety of color change requirements and the use of non-recovery system for small batch production can also obtain higher economic benefits, the flexibility of production makes the application manufacturers in the product Variety is more competitive.
Friction electrostatic guns have the advantage of good permeability (such as various aluminum profiles and deep groove workpieces) when spraying complex workpieces.
The use of friction guns requires the use of special friction powders. With the continuous improvement of the powder production level, more and more powder manufacturers produce spray powders suitable for high pressure guns and friction gun applications.
Spray powders usually consist of the following three different sizes of powder particles:
Fine particles: less than 20 microns
Medium particle: 20-45 micron
Coarse grain: 45 microns or more
It is obvious that different sizes of particles produce different frictional electrostatic effects. Smaller particles get larger contact friction effects when rubbing the tubes with friction guns, and have a greater chance of colliding with the wall. Therefore, the effect of frictional charging can be quickly achieved. Medium particle powder is suitable for friction gun spraying applications.
Advantages of friction gun
1, can use a comprehensive automatic spray, save labor.
2. Compared with high-voltage electrostatic guns, the surface quality is more perfect and smooth.
3, the surface coating uniformity is perfect.
4, to overcome the Faraday effect, especially for complex workpiece spraying.
5, the high rate of powder, reducing the investment cost of equipment
Friction spray for smoother surface quality
Generally, the surface quality obtained by frictional spraying is smoother and smoother than that of the high-voltage electrostatic gun because the frictional spraying powder does not cause electrostatic repulsion on the workpiece due to stacking, thus overcoming the resulting “orange peel effectâ€. The electrostatic "orange peel effect" of the powder is usually produced in the following situations:
1. When the powder particles accumulate on the workpiece surface too thick, the outer layer particles cannot be sufficiently grounded, repel each other, and have a repulsive effect on the particles that continue to spray the workpiece, affecting the efficiency of the powder and the surface quality. Surface irregularities and even blistering may occur on the surface of the workpiece.
2. Excessive powder may also cause a slight gap between the coating and the surface of the workpiece, resulting in an orange peel surface.
3, high voltage electrostatic high. If the high-voltage static electricity of the powder is too high, it will also cause the orange peel on the coating surface. The friction gun can avoid this phenomenon when spraying.
4, the leveling and curing process is not perfect, the temperature distribution in the curing furnace is not uniform, the workpiece temperature is not complete.
Friction Gun Spraying Notes
1. When spraying, use the first friction gun to perform “initial†spraying on the workpiece to achieve the grounding effect of the workpiece. This will allow the workpiece to produce a "preheating" effect, improving the efficiency of the subsequent powder coating.
2. Adjust the spraying angle between the spray gun and the workpiece so that the workpiece has the longest possible contact time with the spraying powder. Try to make the sprayed powder have a large contact time with the workpiece.
3. When spraying workpieces with deep grooves, two sets of guns can be used. The first set of guns sprays the interior of the deep tank at a short distance with high powder output. Because the distance between the nozzle and the workpiece is close, the interior of the deep tank can be sprayed. The second set of spray guns is located far from the workpiece and is sprayed to the outside of the workpiece at a low rate of powder discharge.
4, to avoid the spray gun spray of the cross, spray crossover can not improve the spray effect, but will cause spray amplitude confusion.