Grant: Collaborative Research and Development Grants

Electrostatic painting and powder coating are well established industrial processes in wide use in the automobile industry. However a number of challenges exist in achieving maximum transfer efficiencies under all conditions. Furthermore quality control issues such as non-uniform paint coating, back corona in powder coating etc occur on occasion. The normal approach to resolve these problems is to vary the operating parameters empirically. However because of the large number of variables involved, this often is ineffective. Prior efforts to model the process have had serious shortcomings because they have been limited in their assumptions and restricted to either electrostatic or aerodynamic forces. The goal of this project is to improve a recently developed numerical model for simulating electrostatic painting and powder coating processes so that it can be used in practical industrial situations for determining near-optimal process parameters. In particular improvements will be made by developing new coding algorithms to improve the meshing and visualization of the outputs with the capability of modeling multiple forms of moving 3D targets. This will be followed by a detailed study of the liquid spraying/coating process using high speed rotary bells with particular emphasis on the process of conduction and corona charging of the droplets. This will include experimental verification using data provided by General Motors of Canada. Following this validation, multi-variable optimization techniques will then be used to determine the best operating conditions. In addition the model will be extended to also include aspects specific to powder coating such as tribo and corona charging, the Faraday cage effect and back corona.