Abstract: Investigation is made to improve the process of the production line of a padlock body. With massive data collected, value stream mapping method is applied to analyze the process. Special attention is paid to reduce the wastes of overproductions and high level of inventory. Based on lean thinking, a future state value stream diagram is drawn. Then, the production process is redesigned such that the balance of the line, quality control, and production planning are improved. Furthermore, the operation of the production line and inventory are controlled by using KanbanSupermarketbased methods. Consequently, both product through time and WIP are reduced by 92.8%.

Key words: value stream, value stream mapping, production line