The application of the Six Sigma method in reducing the defects of welding on the steel material

Quality control is an essential factor in producing products that are following what consumers want. The high quality of the product significantly affects the efficiency of costs incurred during the production process. This study aims to determine the types of defects and their causing factors as well as actions taken to reduce the number of defects to increase the efficiency of production costs. The measurement results obtained the number of productions of 12499 pcs with the number of defects of 2712 pcs of 21.6% with a sigma level of 3.1100 DPMO. Identification of defects in welding is porosity defects of 724 pcs, undercut defect of 613 pcs, slag defect of 435 pcs, crack defect of 491 pcs, and spatter defect of 449 pcs. The actions taken are periodic maintenance and repair of welding machines and connectors, supervising the condition and cleanliness of the material, providing periodic directions to welding operators by explaining reasonable welding procedures and arranging a welding field development program for welding operators through a job training program. Improvements have been implemented and found a reduction of defects up to 15% and a reduction of 6.6%.