Droplet and Flake Size Distribution in the Electrostatic Spraying of Metallic Paint

When compared with conventional spraying, electrostatic spraying of metallic paints is known to result in a change of color of the deposited paint film. An earlier study, by other researchers, suggested that this phenomenon is due to a difference in the flake content in the deposited paint. This paper confirms that finding for an electrostatic rotary-bell spraying system, and expands on it to determine the effect of various system operating parameters on the resulting paint droplet and flake size distribution. Parameters selected were the applied voltage, speed of rotation of the bell and the gap spacing between the sprayer and the target. The paint-sample collector, which is a high-voltage electronically-driven device, is also described. Operating parameters are found at which the droplet size and flake content are most uniform along the target surface.