Process control for electrostatic powder coating
1. Voltage setup
In certain circumstance, the adhesiveness of powder coating will increase when the voltage setup increase. However, when the voltage surpasses 90KW (actual voltage), the adhesiveness will decrease in the case.
2. Distance between spray gun and work piece
Normally, it is suggested to keep the linear distance between spray gun and work piece at 150-300mm.
When the distance is too long, the influence of the voltage on the painting thickness will decrease. When too close, it is easy to get pinhole defects because the film is broken due to too high voltage.
3. Control of powder spray amount
Initial increase of painting thickness is proportional to spray amount. However, when the painting time lasts, the increase of spray amount has less influence on the painting thickness increase and furthermore decreases piling efficiency.
Normally, the spray amount is suitable at l00-200gimin.
Special tips
Three factors have obvious influence on the painting result: gun distance, voltage and spray amount.