EFFECT OF PARTICLE DENSITY AND COMPOSITION ON MIXTURES DURING NONELECTROSTATIC AND ELECTROSTATIC POWDER COATING

摘要

Nonelectrostatic and electrostatic coating processes cause the proportion of each powder in a mixture to be different on the target than in the initial mixture. First, some loss of powder occurs during the targeting step; thus, not all of the powder lands on the target. This targeting loss is caused by the individual powder characteristics and interactions that occur between powders in the mixture. Also, an uneven distribution is produced on the target because of the way the powder is dispersed. Finally, adhesion loss occurs on the target, also because of individual and mixture characteristics. During nonelectrostatic coating, a mixture of fine NaCl and starch particles changed in proportion due to the differences between individual targeting, and mixture adhesion, losses. Little change in proportion occurred in the coarse NaCl and starch mixture. During electrostatic coating of both mixtures, proportions changed because of differences between individual adhesion losses.