Using fuzzy cost–time profile for effective implementation of lean programmes; SAIPA automotive manufacturer, case study

Abstract

Today, many manufacturing companies have turned their attention to leanness. The first step in implementation of lean manufacturing is identification of wastes and values in the production processes where value stream mapping (VSM) by using the current state map (CSM) and future state map (FSM) is one of the best tools in this area. While VSM has many benefits, there are some limitations that can be considered when considering the time as the only factor in choosing the best FSM among some proposed FSMs. This paper emphasises the effective use of VSM relying on the removal of some of the common constraints in the subject literature, and cost is considered as another major selection factor along with the time, and for each FSM, the new fuzzy approach of cost–time profile (CTP) has been considered and compared. Also, among the other limitations of VSM is considering deterministic data and regardless of the effect of uncertainty in production processes, which in this study, the data of FSM, using fuzzy analysis and taking into account uncertainty is provided. Finally, in order to explain the effectiveness of the presented method, this approach has been implemented in one of the largest automobile manufacturers in Iran.