Using Fuzzy Approach in determining Multi-Level Lot-Sizing Decisions, Multiple Items with Limited Capacity in Systems Based on Material Requirements Planning (MRP)

In a complex multi-level supply chain, material requirements planning (MRP) systems are the most commonly used for production planning and material supply decision making. Nowadays, most large manufacturing companies use the MRP in the process of their production management. Since MRP depends strongly on its inputs, so the smallest change in one of its inputs can cause too much change in its calculation. In many cases, because of demand uncertainty, limited resources, and unknown costs, using the classical methods seem unreasonable to solve these problems. In this research a new method, using a fuzzy expert system in estimating fuzzy parameters, is provided for determining multi-level lot-sizing decisions, multiple items with limited capacity, medium-term production planning with limited capacity, multi-product, multi-level and multi period manufacturing environment. Considering uncertainty in parameters, a fuzzy linear programming, using α - cut concept, is developed to transform the fuzzy model into a crisp linear programming. Finally, the developed model is tested in a home appliances manufacturing company.