Reducing Warranty Claims and Defects in a Motorbike Industry of Bangladesh Using Lean Six Sigma

The main goal of this study is to reduce the number of defects and warranty claims to improve quality in a local motorbike industry. Therefore, Lean Six Sigma was applied in this company at the Jashore plant. Initially, the top five warranty claims were identified and the four major defect areas: material, welding, paint shop, and assembly. Then the DMAIC was applied methodology to improve key performance indicators such as First-Time Right (FTR) and total pass rate, as well as the Six Sigma level. Various Lean tools, including FMEA analysis, DPMO, control charts, Pareto diagrams, fishbone diagrams, 5S, Poka-Yoke, and 5W+1H. In particular, root cause analysis was applied to identify the main reasons behind the increasing number of defects. As a results, The Six Sigma level increased from 3.53 to 4.0075, and the defect percentage decreased from 8.57% to 2.22%. The total number of defective parts during assembly was reduced from 28,772 to 19,174, and the overall pass rate improved from 90.21% to 97.47%. As a result of this research, the company improved quality and reduce costs by implementing the Lean tools as per our recommendations.