Optimization of metal phosphating parameters in static powder coating process

This study aims to optimize the phosphate coating parameters of an enterprise producing steel doors in the electrostatic powder coating process. In order to save time and cost, the number of experiments was reduced from 27 to 9 using the Taguchi L9 orthogonal array. While keeping the iron phosphate coating process constant, variables such as temperature, pH level, and coating duration were investigated. After painting the samples with the same paint brand, the effect of phosphate coating on the paint was evaluated using a salt spray test. The effect of controllable factors (temperature, pH level, conveyor speed) was attempted to be minimized using the Signal-to-Noise ratio. Regression analysis and validation experiments were conducted to calculate the effects and reliability among them after the Taguchi experiment. The study found that the optimum result was achieved when the pH level was set to 5.5, coating duration was 4 minutes, and temperature was 28°C. Validation experiments and statistical analyses conducted provide evidence of the accuracy of the experiment.