Application of Six Sigma Method with DMAI Approach in Railway Manufacturing Company

Abstract

As one of railway manufacturing company in Southeast Asia, quality is an important factor in maintaining customer satisfaction and one of the key success in business competition. During the railway production, there is problem in the assembly process of car body sub assembly, namely underframe. Defective products have been found which cause the underframe to be repair, so the underframe production is delayed. The type of defect is porosity, which results from the welding process during the assembly process. Therefore, this study uses the Six Sigma method with the Define-Measure-Analyze-Improve (DMAI) approach to give improvements on welding process so the defect-which is porosity will be reduced or may not exist and to maintain the quality. Define phase using Supplier-Input-Process-Output-Customer (SIPOC) diagram and Critical to Quality (CTQ). Measure phase using c-Chart to know the process stability, then Cp and Sigma Level to know the process capability. Fishbone diagram and Failure Mode Effect Analysis (FMEA) are used in the analyze phase. The result of FMEA is the base to design improvements in the improve phase, the improvements are material storage characteristics, workstation design and procedure display.