A Novel Dynamic and Fuzzy Value Stream Mapping (DFVSM): System Dynamics and Fuzzy Logic Integration

Value stream mapping (VSM) is a method to identify waste and activities that do not add value. One of its main disadvantages is that the parameters used in the process and material flows are deterministic. The motivation of this research is to improve the reliability of the estimation of the lead time in VSM, transitioning from a static model to a dynamic model that incorporates uncertainty and imprecision in the data, as well as to develop a novel dynamic and fuzzy value stream mapping (DFVSM) based on integrating system dynamics and fuzzy logic. One of the main contributions of this research is to develop a fuzzy system in the same system dynamics interface that incorporates uncertainty and vagueness to the efficiency and effectiveness percentage variable (OEE%) to increase the reliability of the delivery time planning. The stages of DFVSM are explicitly described and applied to real data for a textile company in southern Guanajuato. A sensitivity analysis of the proposed model was integrated which identifies the critical factors for the delivery of the order, and achievable times were proposed for the delivery times of the supplier and the client, thus reducing the expected delivery time by 28%. One of the relevant conclusions of this work is that, to plan the lead time of an order, the uncertainty of the main parameters such as supplier and customer shipping times be considered to satisfy the customer.