Insulation powder film forming defects and solutions
The problems that occur during the use of insulating powder are summarized below for reference.
4. Dimples in the coating film: improper handling, impure oil removal; source contamination, compressed air deoiling, incomplete water removal; uneven workpiece surface; contamination by dust or other impurities.
5. Bubbles appear on the coating film: after the surface treatment of the workpiece, the moisture is not completely dried, leaving the pretreatment residual liquid; degreasing, rust removal is not complete; the underlying volatiles are not removed; the surface of the workpiece has pores; the powder coating is too thick.
6. Uneven coating film: uneven powder spraying; the distance between the spray gun and the workpiece is too close; the high-voltage output is unstable.
7. The coating film has poor impact strength and adhesion: the phosphating film is too thick; the curing temperature is too low, the time is too short, so that the curing is not complete; the bottom metal is not cleaned; the coating will reduce the adhesion after being immersed in water.
8. Pinholes in the coating film: the air contains foreign objects and residual oil; the voltage of the spray gun is too high, causing the coating to break down; the distance between the spray gun and the workpiece is too close, causing the coating to break down; the coating is too thin; the coating film is not sufficiently cured .
9. A small amount of sand particles appear on the surface of the coating film: the spray is clogged or the air flow is not good; the atomization of the spray gun is not good; there is powder dripping in the powder spraying room; other debris contaminates the surface of the workpiece.
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10. The coating is off: the surface of the workpiece is not well treated, and the degreasing and rust removal are not complete; the output voltage of the high-voltage electrostatic generator is insufficient; the workpiece is poorly grounded; the air pressure is too high when powdering;
11. Uneven powder supply: the powder supply tube or powder spraying tube is blocked, and the powder adheres and hardens at the nozzle; the air pressure is insufficient and the pressure is unstable; the air compressor is mixed with oil or water; the fluidization of the powder supply is unstable, There is too little powder in the powder feeder; the powder supply tube is too long, and the resistance increases when the powder flows.
12. Powder flying and poor adsorption: the electrostatic generator does not have insufficient high voltage; the workpiece is not well grounded; the air pressure is too large;
13. The amount of powder spraying is low: insufficient air pressure, insufficient air volume; too high air pressure, the proportion of air in the mixture of powder and flow is too high; water vapor and oil pollution are mixed in the air space; the spray gun head is partially blocked.
14. The powder spray tube is blocked: Due to the material of the powder spray tube, the powder is easy to adhere to the wall of the tube; the output tube is heated, causing the powder Lin in the tube to agglomerate; the powder conveying tube is bent and distorted; the powder is mixed with more granular impurities.