Research On Two-dimension Irregular Packing Problem For Product Preparation Of Discrete Manufacturing

The material preparation process is one of the basic processes in the product production and processing process of discrete manufacturing enterprises,and it has a significant impact on the manufacturing quality of the product.The part packing process is the basic step unit of the material preparation process.For discrete manufacturing enterprises,the diversity of orders leads to different sizes and specifications of parts,and different processing methods lead to different specifications of blanks.Regarding the irregular part packing problem during the cutting process,firstly,the basic theory of part data optimization and graphic algorithm is analyzed and studied,then the problem of small-batch single blank packing is discussed and studied,and then corresponding solutions is proposed,and finally,the effectiveness of the packing method through the packing platform is verified.The main research work is as follows:(1)For the problem of reading and analyzing basic polygonal data of irregular parts,the calculation method of concave-convexity classification of polygonal parts is studied,and then theoretical analysis and research from four aspects of polygonal parts: hole,area,centroid and motion analysis is carried out.Finally,the problem of reading part polygon data is studied.By parsing the drawing exchange file(Drawing Exchange File,DXF)of the part polygon and saving the data after optimization,the data foundation is laid for the calculation of the subsequent packing algorithm.(2)For the packing of small and medium-sized parts on the single blank,firstly,a mixed integer programming model is established based on the non-fitting polygon solution method of combined parts to improve the solution efficiency.Secondly,a pixel method is designed to solve the problem of material waste of parts with holes.Then,an improved ant colony algorithm is used to determine the layout order of parts,the Latin hypercube initialization method is used to improve the quality of the initial population,and an adaptive pheromone update strategy is proposed to improve the search efficiency of the ant colony algorithm.At the same time,in order to solve the problem that the algorithm is easy to fall into local optimum,a hybrid mutation strategy based on genetic mutation and 2-opt mutation is introduced to enhance the local search ability.Finally,the effectiveness of the packing algorithm is verified through standard cases and actual enterprise data.(3)For the packing problem of large-scale parts on multi-standard blanks,the corresponding mathematical model is established,then an improved iterative local search algorithm is designed to solve the problem.In order to improve the quality of the initial population,a mixed greedy initialization method is designed based on the single packing method,and pixelation strategy,part insertion strategy and hot start strategy are integrated into the local search algorithm for packing processing.Then,a differential crossover strategy is proposed to improve the global search ability of the algorithm,and an adaptive crossover operator improved by the sigmod function is introduced to adjust the crossover probability adaptively,so as to improve the search efficiency of the algorithm.Finally,the feasibility and practicability of the algorithm are verified by the standard data set and the actual data of the enterprise.(4)According to the theoretical research content and the actual production needs of the enterprise,an intelligent packing platform is designed to verify the application of the packing method,the relevant platform development architecture and tools is introduced,the logic,structure and function modules of the packing-related data is designed.Through the actual data of enterprise,the effectiveness of the packing method of single-plate blanks and multi-standard blank are verified,and the packing processes in different modes are completed within an effective time to meet the actual production needs of enterprise.