Improvement of Paint Thickness in Electro Deposition Painting Process of Truck Manufacturing

Abstract

The objective of this research is to improve process capability and reduce production cost related to thickness of paint from Electro Deposition Painting (EDP) process. To achieve the objective, Six Sigma method was applied to find out the optimal setting of significant process factors, which are concentration of pigment in EDP paint, dipping time, and dipping voltage. Design of experiment technique with Central Composite Design type helped indicate the optimal setting of the three factors, which yielded the target EDP coating thickness with a minimal production cost. With this optimal setting, the process capability index (Cpk) increased from 0.61 to 1.99, and the production cost is expected to reduce by 1,730,498 THB per year.