The Application of Lean Production on Punching Line of F Company
This paper systematically analysis the production situation of the punching line of F Company, and uses Single Minute Exchange of Die, Process Flow Diagram and ECRS principles to improve the punching line. After the improvement, the time that needed to exchange the die is shortened to half of the original. Introduction F Company aims at the development and production of parts of saloon cars, and it mainly produce punching part and weld assembly. The company implements a production mode that is called Multi-specification & Small-batch, and each workshop should produce hundreds of products, so that workers have to exchange the mold frequently. If the company can not systematically standardize their ways of die exchange, their productivity would be limited. This paper takes the punching line of F Company as an example, and illuminates the application of Single Minute Exchange of Die to reduce the time it takes. Single Minute Exchange of Die Die exchange, also known as Settings or Preparation, is the practice that change a line or machine from running one product to the next. The process of die exchange is mainly composed by 4 parts: Preparation, die exchange, adjustment, readjustment[1,2]. The SMED is a Process improvement method that base on industrial engineering to reduce the time it takes to exchange die, and setup or adjust the equipment.The name Single-Minute Exchange of Dies comes from the goal of reducing changeover times to the “single” digits, in other words, it means to reduce changeover times to less than 10 minutes[3]. In SMED, the changeover time includes the following parts[4]: 1. Internal changeover time (must be completed while the equipment is stopped); 2. External changeover time (can be completed while the equipment is running); 3. Adjustment time (guarantee the quality and deal with failure while the equipment is stopped). The Original Changeover Process The punching line of F Company is located in the press shop, and mainly consists of 4 machine tools, which are called C1, C2, D1, D2, respectively. Those equipment are responsible for processing cutting angle, drawing, shaping and marking, and trimming. The overall layout of the punching line is shown in Figure 1. And Table 1 illustrates the original changeover process, which is based on On-site Data and facts. Table 1 illustrates the original changeover process, which is based on On-site Data and facts.As table 1 indicates, the process takes 51.6 minutes in total, and workers need to move 69 meters. In addition to that, there are 29 activities, including 18 operations, 9 moves, 1 storage, and 1 hold. All of this make the line become so inefficiency, so that, the workers failed to completed production plans on time. After a series of study and analysis, we can find out the primary causes of this line: