Theory Of Constraints-based Production Planning And Control Of Modeling And Simulation Study

The allocation of manufacturing resources is always the hot topic of research. The requirements of the efficiency, punctuality and flexibility become more and more important facing the fast changing market environment. TOC (Theory of Constrains), proposed by doctor Goldratt, is one of the most important morden production management theory and methods. But, for the complexity hybrid production scheduling under multi-product and small lot-size environment, the bottlenecks are difficult to be identified and drifting with different products mix or tasks combination because of the stochastic features of manufacturing systems. Therefore, in practice, it is very difficult to be determined the parameters of DBR scheduling method, which include the location of bottlenecks, location of buffers, sizes of buffers, transfer lot-size and task lot-size.On the base of the study of theory of constraints, modeling and simualation, the metheod of DBR production planning and controlling based on discrete event modeling and simulation is proposed. The improved method first collects the production system data such as task data, process data and capacity data and builds the model of the production system using discrete event modeling and simulation software, and then run the model to determine the location of bottleneck. After identifying the bottleneck, the parameters of DBR are determined and optimized through simulation and simulated annealing algorithm. At last the scheduling with DBR is implemented according to the optimized parameters.On base of the improved method, a specific scheduling example for products mix is given. The results show that the improved DBR scheduling method can effectively overcome the weakness of original DBR, which is proven to be helpful to increase the throughputs of system and lower WIP.