Fuzzy Inventory Control In Hybrid Manufacturing/Remanufacturing Systems

In recent years, with the deterioration of the environment and people's environmental awareness has been continuously strengthened, some countries have begun to make relevant laws and required the manufacturer to be responsible for the product life cycle, and to recycle used products for reusing or environmental protection treatment. Remanufacturing being one of efficient forms of product recovery has received extensive attention from industrially advanced countries and become one of the most efficient approaches that realize the sustainable development.Original equipment manufacturer is usually responsible for the remanufacturing of used products, which forms hybrid manufacturing/remanufacturing systems (HMRS), and inventory control is one of the key problems that need be solved in HMRS. Compared with the traditional inventory management, inventory control of HMRS is much difficult, this is because that the HMRS include manufacturing inventory and return and remanufacturing inventory, and the quantity, quality and return time of used products are uncertain. Therefore, it is essential to do an in-depth study about inventory control of HMRS.Based on the existing literatures and aiming at the characteristics of hybrid manufacturing/remanufacturing inventory systems, inventory controlling of HMRS under fuzzy is studied. First, basal fuzzy model is developed on the basis of the assumption that the demand rate and the return rate are characterized by fuzzy numbers. The signed distance method is employed to solve the model, the validity of the model is demonstrated by an illustrative example, and the influence that fuzzy demand rate on total inventory cost per unit time is analyzed, and then developing the basal model from three aspects. First, the lead time is taken into account, after analyzing the deferent influence that fuzzy lead time and certain lead time on total inventory cost per unit time, the change of total inventory cost per unit time of HMRS under the lead time of manufacturing and remanufacturing is equal or not two situations are studied. Second, disposal of returned products is considered, two fuzzy inventory models are developed, the signed distance method is employed to solve models, the illustrative example is developed to analyze the influence that disposal on total inventory cost per unit time of HMRS. Last, two fuzzy inventory models that return and demand are related are developed and the signed distance method is employed to solve models, the illustrative example is developed to analyze the influence that the coefficient distribution of return rate in each return period on total inventory cost per unit time.