Simulation Optimization For Bogie Axle Box Assembly Line Based On SPS Feeding Mode

With high-speed trains of our country entering the international market and the implementation of the national strategy of Intelligent Manufacturing,the market competition is more intense,the types of high-speed train products are more diverse,which makes the highspeed trains manufacturing enterprises face the pressure of realizing multi-variety flexible production and upgrading manufacturing level.Material supply is the key segment to control production cost and ensure JIT production.The traditional material supply mode of line-side warehouse has been unable to meet the material demand of mixed-flow production,which seriously restricts the production capacity of high-speed train manufacturing enterprises.In order to improve this situation,it is necessary to introduce advanced material supply mode.In this paper,the axle box assembly line of a high-speed train bogie workshop is taken as the research object.Aiming at problems existing in the traditional feeding mode of the line-side warehouse,such as the expansion of the line-side warehouse,the accumulation of WIP occupying production space,and the untimely distribution of materials,the SPS feeding mode of the automobile industry is introduced into the axle box assembly line to improve its material feeding mode.The main research work is summarized as follows:(1)The automatic axle box assembly line based on SPS mode is researched,and the AGV movable assembly station is used for the synchronous automated transportation of products and materials.The assembly line is divided into six workstations to balance the workload of the assembly line and eliminate the bottleneck.Based on the analysis of various picking modes,strategies and methods widely used in current logistics distribution centers,automatic warehousing system and automatic sorting system are applied in SPS distribution area by using the "Material-To-Man" picking mode to produce material complete sets and improve work efficiency.(2)The simulation experiment of the "Material-To-Man" sorting system in SPS distribution area is carried out by using Plant Simulation.Aiming at minimizing the total flow time of each material box in the sorting line,the optimization method combining simulation model and Genetic Algorithm is adopted to optimize the sorting of the material box,and the optimal arrangement sequence of the material sorting station for the motor wheelset axle box and trailer wheelset axle box and the material box circulation sequence under the alternating arrangement mode are determined.Aiming at minimizing the average picking time of a single set of materials,and taking the number of sorting stations and the arrangement order of material sorting stations for motor and trailers wheelset axle box as factors,the optimum arrangement of material sorting stations for motor,trailer wheelset axle box and buffer stations in the sorting line was obtained.Finally,the reliability of the test results is verified by factor crossover test.(3)3D simulation models were build for two kinds of assembly lines.The evaluation indexes of assembly line were selected as workstation utilization rate,worker utilization rate,average flow time of WIP,average waiting time of WIP,number of WIP and average daily output.Through the comparative of these six evaluation indicators,it can be concluded that SPS mode improves the productivity of assembly line and the utilization rate of workstation and workers,reduces the average flow time and waiting time of WIP,as well as the number of WIP.The validity of SPS feeding mode is verified by simulation and comparison.