Research On Simulation And Optimization Of Body-in-white Welding Line

In order to meet the huge demand for automobiles at home and survive in the strong competitive pressure of the industry,automobile enterprises must improve production efficiency to reduce production costs,in order to ensure that the automobile production can meet market demand,and at the same time,make themselves competitive.Body-inwhite manufacturing is a key step in the automobile production.Welding is one of the four major processes of body-in-white production.Therefore,it has great significance to study the simulation and optimization of the body-in-white welding line.Firstly,the technological process and equipment composition of the body-in-white welding line is introduced,and the buffers which including the buffers in the subproduction lines of the welding line and the buffers between the sub-production lines are determined as the key optimization object.Then a body-in-white welding line is taken as an example to determine the goal and scope of its model and make the simplification and hypothesis.On the basis of data preprocessing,the simulation model is established by using a production system simulation software called Plant Simulation.The evaluation of the simulation results proves the necessity of optimization.Secondly,the sub-production lines of the body-in-white welding line is optimized.A two-stage and multi-stage experiments by using DOE(Design of Experiments)method is carried out.The influence of failure rate on production is analyzed and the key workstations which need to be optimized is determined.The comparative experiments proves that adding buffers to the production line can improve the balance and the output of it.The location and optimum capacity of buffers are determined by using DOE method,and the overall optimization scheme of buffers in twelve sub-production lines of the welding line is summarized.Finally,the optimization of the EMS(Electric Monorail System),which is an important part of the body-in-white welding line,is studied.Different from previous scholars’ research focus,this paper optimize from a new point.The single factor analysis is carried out by using DOE method,and the effects of EMS trolley’s number and speed on the output of the welding line are studied separately.The interaction between them is considered,and multi-factor analysis is carried out.Then the method which combines genetic algorithm with production system simulation software to carry out multi-objective optimization analysis is put forward.Using the GAWizard module in Plant Simulation software to design multi-objective genetic algorithm,and the optimal ratio of trolley’s number and speed are obtained.It provides a new solution for simulation and optimization work in the future.In addition,in order to make the optimization scheme more complete,the optimal capacity allocation scheme for the other buffers between the sub-production lines is also proposed.The research of this paper comes from an actual production project of an enterprise.A systematic set of optimization scheme is summarized,which provides a certain of references for the planners who plan the body-in-white welding line.