Group-based Job Shop Scheduling For MTO Production

In manufacturing companies of orders, each order is different. It needs to be analyzed.The production plans also need to be developed by companies. From the beginning of ordersto the final delivery of the user, orders have obvious starting point and final point. Howeverthe market is increasingly competitive, if the company can complete the order quickly, it seizesthe initiative. So its scheduling requires stronger ability to handle. For minimizing the deliverytime, the production needs to be broken up rapidly and integrate the orders. There also havemany uncertainties. The deficiencies of raw materials will lead to the final product can notsatisfy the needs of customer. Make the enterprises not to get great loss.In recent years, the group technology is introduced into the study of productionscheduling. The idea is that different products in a similar process parts are combined togetherto be scheduled. Because the group of orders decreases the preparing time and cost, theprocessing cycle can greatly shorten, production costs can be reduced and production qualityis improved. However, how to determine the size of group is the problem needs to be solved.In the multi-variety and small-batch orders production environment, job shop schedulingbased on group technology is studied for solving the increasing production preparation time.The degradating production efficiency caused by the diverse orders.In the multi-variety and small-batch orders production environment, it has different duetimes and processes. The problem model which decreases wait time and production costsbased on group technology is described.Based on group technology, the group strategy of orders is proposed. It not only considerssimilar due dates but also concerns the similarity of order processes between components. Ittakes group orders and generates virtual parts. The shortest completion time is taken as theperformance index of the job shop scheduling model based on virtual parts. Furthermore, thejob shop scheduling problem of multiple orders, multi-product and small-volume is convertedinto a appropriate and easy form.The size of the group has a great impact to production scheduling results, so theoptimization algorithm of group size is proposed, which uses the indexes for evaluating toelect the optimal grouping result. The allocation and schedule of order is combined. Ant colony algorithm of elitiststrategy is designed to solve this mathematical model. The scheduling results of virtual partsshow that the orders grouping strategy is effective. The optimal scheduling consequencedemonstrates the optimization algorithm of group size is efficient. The simulation results of acase also display ant colony algorithm which resolves the problem is feasible and effective.