Research On Comprehensive Scheduling Algorithms For Different CNC Machine Tools

The advancement of science and technology leads the development of various industries,and also changes people's demand for products.The traditional manufacturing industry takes mass production as the starting point and distributes products in processing workshops and assembly workshops for processing.With the enhancement of people's consumption concept that the scarcity is the most valuable,scholars have conducted in-depth research on the problem of processing and assembly when producing multiple varieties and small batches of products in order to replace the traditional production methods that are not suitable for today's environment.In view of the problem that in the past,comprehensive scheduling did not consider the impact of the adjustment on subsequent processes in processing the non-occupied time of the machine tool in advance of the corresponding process.A comprehensive scheduling algorithm for dynamic adjustment of non-occupied time period of common machine tools is proposed.In this algorithm,the linear equation is constructed by using the influence factors which affect the process priority.Get the product demand of each process.According to the process priority of product demand degree,the pre scheduling scheme is obtained.In the process of traversing the unoccupied time period of the pre scheduling scheme,the process advance strategy of the unoccupied machine tool is adopted,which depends on the driving state of the machine tool and the logical relationship between the processes in advance,that is,the path process of the process with the highest product demand in the scheduling process;finally,the processing scheme is selected based on the idea of low total unoccupied time of the machine tool and high parallelism of the machine tool.The experimental results show that the algorithm solves the problem of adjusting the non occupied time of the current machine tool,and has advantages over the existing algorithms.At present,the processing mode of enterprises is developing towards the direction of CNC machine tools,and will become the mainstream processing mode.However,in the past,flexible processing mainly used machine tools to find working procedures,so as to reduce the state of "idle machine tools" as much as possible,but ignored the constraints between working procedures.This paper presents a comprehensive scheduling algorithm considering merging optimal tree in NC workshop.The algorithm allocates the processes to different scheduling sets according to the shortest processing time,determines the merging optimal tree of each scheduling set according to the product process tree,and obtains the scheduling order.The optimal timing strategy is proposed,which uses the delay degree and total time extension degree of the scheduled processes to calculate the scheduling order According to the process influence degree of the insertion position of the entry process on each Machinable machine tool,the insertion position with the lowest process influence degree is selected to insert the process..Experiments show that the algorithm adopts the method of prioritizing long-term procedures and interspersing short-term procedures with long-term procedures,which reduces the processing time of complex products on CNC machine tools and has practical value.Considering the problem of balancing the machine tool and the priority of process,a combined optimal tree scheduling algorithm considering the balance of CNC machine tools is proposed.Based on the combination of the optimal tree,a scheduling process balancing strategy is proposed,which takes the priority of the processing time of the machining process and the processing time of the current scheduling process to determine the machine tool that will be inserted into the process.The insertion position is determined by the process influence degree.The example verifies that the algorithm considers the balance of the machine tool based on the priority of the process.While maximizing the parallelism of the machine tool,it prevents the process from preempting the machine tool from affecting the overall scheduling effect,and further reduces the processing time.This paper starts from the general machine tool comprehensive scheduling problem and extends it to the numerical control machine tool comprehensive scheduling problem.The machine tool balance and process priority are considered together to maximize the parallelism of the machine tool.Through the example verification,the algorithm in this paper can achieve good results under certain time complexity conditions.Effect.Therefore,it has certain theoretical and research value.