Study On Production Planning & Control Method Based On Theory Of Constrains

Theory of Constrains (TOC) has attracted extensive attention from enterprises to researchers since it was reported by Goldratt in 1980s, which is a new management mode following up MRP II and JIT system, and its superiority can be seen in many fields. Because of the confidential algorithm, problems such as the bottleneck identification, buffer size setting, lot size and production scheduling is still the emphases on which researchers focused. Only these problems are solved, could TOC be widely used in actual production system.Compared with MRP, JIT production systems, advantages of TOC are pointed; Basic idea of TOC, such as index system, nine principles, key steps, and DBR(Drum-Buffer-Rope) planning and control system are expounded.Through analyzing run status of the workstations before bottleneck and assembly resources, a mathematic model is bulit based on reliability of production system; Based on minimizing the system gross cost, optimum task lot and transfer lot sizes of bottleneck and non-bottleneck resources are determined.On base of studying on simulation and optimizing algorithm, method of DBR production planning and controlling based on Arena simulation and Tabu Search optimizing algorithm is proposed. The improved method first builds a simulation model for the production system, then identify the bottleneck after the simulation running, and determine time bufffer size of the bottleneck; Results are optimized using Tabu Search algorithm. At last, the best task scheduling scheme for bottleneck is got, also scheduling plan for non-bottleneck resources can be determined on based of DBR principles. In the end of this paper, an example is given and studied to validate feasibility of this method.