Electrostatic powder coating process optimisation by implementing design of experiments

Abstract

The coating process of tractor cabs is performed in industry by the electrostatic powder coating technique, which is the electrostatic application of powder to metal parts of the cab, requiring a protective coating. This process ensures the application of powder coating on e-coating (cataphoresis painting) to meet the minimum requirements of the atmospheric corrosivity class of C4-H (in accordance with ISO 12944). Initially, the Taguchi method was used to investigate the effects of process parameters on the response and reduce the number of parameters. Then response surface methodology - RSM - was utilised for modelling a mathematical relationship between the process parameters and the response, namely dry film thickness (DFT). Optimisation was performed to meet the minimum 75 micrometre DFT requirement. The results indicate that the RSM provides reliable quality achievement.