Increased competition and rapid technological growth has completely revolutionized the way businesses are conducted in today's world. Manufacturing companies are consistently focusing on improving their operations efficiency by getting lean, which focuses on the reduction of all sorts wastes involved during the production. The manufacturer is a supplier to renowned car manufactures. The aim of the project was to reduce the in house defects in order to minimize the time and labor involved in reworking the harnesses. The six sigma's DMAIC (Define Measure Analyze Improve Control) methodology was adopted as a basis of this book in order to decrease the variability and defects thereby leading to significant improvement in profits and product quality.