Integrated Scheduling Method And Information System Design For Complex Products Based On Bottleneck Process Identification

With the development of economy and the progress of science and technology,the production efficiency of enterprises has been continuously improved and the speed of product change is accelerating.With the increasing diversification and individuation of customer demand,multi-variety and small batch production has become the main mode of production of enterprises.Shop scheduling is one of the core links in production and management of enterprises.Optimization of job shop scheduling not only improves the efficiency of enterprise resource utilization and customer response,but also improves the overall production management level of enterprises to meet the needs of diversification and individuation in the future complex and changeable market.At present,most of the researches on multi variety and small batch scheduling management are conducted by traditional scheduling methods,that is,pure processing and pure assembly scheduling problem.This method is used to deal with the complex products with tree structure,which not only separates the inherent parallelism of the processing and assembly of the product,but also affects the production quality and efficiency of the product.Therefore,it is of great academic value and practical significance to study the integrated scheduling problem of complex product processing and assembly parallel processing.However,the theory of constraints holds that there is a bottleneck in any production system,which controls the operation and restricts the effective maximum output of the whole system,and restricts the exertion of its link capacity.In order to improve the maximum output of the system,it is the most effective way to identify,utilize and manage the bottlenecks in the system.At present,the bottleneck identification is divided into a priori Bottleneck Identification and a posterior bottleneck identification.The former means that the bottleneck information in the system can be quickly identified before the start of the task.The latter recognizes the bottle neck on the basis of the system running for a period of time or has obtained the optimal scheduling method,which greatly reduces the important guiding significance of bottleneck information for production scheduling.There are two ways to deal with bottlenecks: the first is to increase bottlenecks;the second is to use bottleneck information.For the first strategy,because most of the bottlenecks are scarce,the price is expensive and the depreciation cost is high,which will lead to the increase in production costs.At the same time,this strategy is not very practical when there is a bottleneck drift,that is,the new bottleneck.The second strategy is to quickly identify the bottleneck information before the start of the production task,and then use the theory of the bottleneck to lead the non-bottleneck,the non-bottleneck to meet the bottleneck production needs in the TOC,and using the bottleneck information as heuristic information for production scheduling to accelerate optimal scheduling and achieve rational allocation of resources.Therefore,the identification and utilization of bottlenecks in production system is of great guiding significance for optimizing production scheduling.Firstly,the paper summarized and analyzed the current situation of Bottleneck Identification and Utilization in workshop scheduling,and pointed out the important role of bottleneck information as the heuristic information of workshop scheduling.Then,the paper analyzed the problems in the integrated scheduling of complex products,and put forward the integrated scheduling problem for complex products from the perspective of system bottlenecks.Secondly,in view of the above research directions,a integrated scheduling method for complex products based on bottleneck process identification is proposed.Firstly,the integrated scheduling of complex product problem is described and its mathematical model is established.Secondly,a new definition is made for the bottleneck process in the job shop.According to this definition,the method of identifying the bottleneck process based on TOC and sensitivity analysis is adopted and the concrete steps and processes are introduced.Then,on the basis of Bottleneck Identification,this paper introduces the overall business process and key technology based on improved genetic algorithm to solve the problem,including multi parameter cascade coding,decoding process and improved crossover and mutation operators.Finally,an example is given to illustrate the feasibility and superiority of the algorithm.Then,there are often some dynamic interference events in the actual production process,such as machine failure,emergency insert,order priority change,and so on.The paper studied and analyzed the dynamic scheduling of job shop.Combined with the above research results,a hybrid scheduling strategy based on bottleneck process is proposed.In the light of two typical events in workshop practice: machine failure and emergency inserting,the paper proposed the processing flow.And the effectiveness and superiority of the proposed method are demonstrated by case simulation.Finally,based on the above research content and results,a complex product integrated scheduling information system based on MES is designed and developed,which mainly included the function of basic information management,complex product t integrated scheduling data management and optimization.The system was tested in Chongqing Hongjiang machinery processing workshop and achieved good application results.