Simulation And Optimization Of Lotsizing For An Automobile Glass Production Line

With the raise of the living standard, the demand of car as a means of transport is increasing, the automotive glass industry which is closely related to the automotive industry has been brought great opportunities and challenges. Automotive glass production process has five process steps:pretreatment process, curving process, high pressure process, assembly process and packaging process, the production scheduling is one of the very important factors for automotive glass production capacity. However, it is often developed by experienced staffs in the automotive glass industry so far. Thus, this not only increases staffs strength, but also causes unnecessary waste and loss, thereby, it will lead to increasing production costs.This paper applies an automobile glass manufacturer as research background, analyze the production problems due to improper scheduling policy, such as the large amount of WIP inventory, low productivity and so on. These problems will increase the cost of production, including the WIP inventory costs of production system, the switching costs between different products and the idle costs of equipment, if reduces a cost often lead to increase other costs due to their contradictory. For example, if reduces the WIP inventory costs, it is necessary to increase the number of the switching to meet the processing needs of the curving process, that will increase the cost of switching, in addition to the constraints of the processing time, the idle cost of the curving process will also increase. In order to reduce the cost of switching, it needs to set up a huge inventory of WIP for meeting the demand of the curving process, so the WIP inventory costs will become quite high. If reduces the idle cost, it needs a large number of the inventory of WIP before the curving process, so it will increase the switching cost and the inventory cost. Therefore, reducing the three costs together is very difficult in a short time, so the paper reduces the total cost of production by optimization the factor of lotsizing during the production.This paper makes theoretical research on lotsizing strategy of automotive glass production based on the status of the actual processing, and establishes a mathematical model for the variable of production lotsizing, it calculates the production lotsizing that makes total cost the lowest by genetic algorithm. To verify the effectiveness of the proposed method, this paper makes experimental research by using simulation method, Firstly it sets up the simulation model of the pretreatment and curving process by eM-Plant software, then obtains the relevant data by running the simulation model, finally, gets the impact curve and function relationship between the lotsizing factor and the three major costs and the total production cost by using the tools of MATLAB to fit these data. The analysis results show that the conclusion of theoretical research is credible and effective.