What makes the powder “stick” to the part?
The two key factors here are, surface preparation and the electrostatic application of the powder. First the parts are cleaned and degreased. This is followed by a pretreatment, typically a phoshatizing agent, or they are sandblasted. Exposure to salt or high humidity may call for an additional treatment. Secondly, the parts are hung on racks that will transport them to the spray booth and eventually to the oven. These racks are grounded. The attached ground ensures that the charged particles will be attracted to the part.
