PARTICLE DEPOSITION IN ELECTROSTATIC SPRAYING OF POWDER COATINGS

The effects of several operating variables on the electrostatic deposition of particles on a flat surface were investigated quantitatively. In general, particle deposition becomes more uniform with a decrease in charging voltage and particle size, and an increase in spraying distance, carrying air velocity and total weight of deposited particles. A one-parameter model which describes the distributiion of the deposited particles when the gun is kept stationary relative to the surface is established, and an empirical relationship between this parameter and the operating variables is presented. Using this relationship, film thickness profile, area coverage, and deposition efficiency at any set of operating conditions can be predicted.