Value stream mapping and system dynamics integration for manufacturing line modelling and analysis

Companies have to meet client's requirements with regard to product quality and delivery time. In order to survive and have possibilities to develop, companies should do it at minimal cost. The lean manufacturing implementation approach together with lean tools, such as value stream mapping (VSM), is an efficient way for waste identification and elimination. However, since VSM enables only a static analysis of a manufacturing system, the authors present in this paper how the integration of VSM with a system dynamics analysis (SDA) may increase the possibilities for waste identification and elimination. At first, the methodology of extended VSM is described. Then, an extended value stream map (VSMap) is developed and a system dynamics model (SDM) for a case study from the automotive industry is presented. Next, simulations in Vensim software are performed considering the inventory limitations and disturbances such as delivery delays, machine failures and nonconformities. The results are related to inventory levels, a number of manufactured products and work stand load. The article proves that the proposed extended VSM may be used as the only source of data for the construction of a manufacturing line computer model. The paper also argues that the integration of VSM and SD allows not only to identify and eliminate waste, but also to understand the impact of the identified problems on WIP and the production volume.