| Cutting layout optimization of wood-based panel(WBP) and NC program generation of layout solution have important theoretical significance and practical value on improving cutting efficiency of WBP and reducing production costs for panel-type furniture enterprises of China. Algorithms which were available in most domestic literatures gave solutions that resulted in frequent change of saw line and therefore dropped sawing velocity down. To solve this problem, based on project of “ Study Demonstration on Key Technologies of Optimization Layout of WBP”, which is the basic scientific research specialized foundation of central level scientific institutes from CAF, the research focused on layout of large scale rectangular parts and studied optimization of cutting layout and interface file of NC program as well.(1) Exploratory study on mathematical model of cutting layout of WBP and realization method of genetic algorithm(GA). In accordance with cutting technology of panel-type furniture layout, a grouping and dimension reducing heuristic rule which took areas of rectangular parts as priority was put forward. According to this rule, no more than three kinds of rectangular parts were considered in each layout calculation, and therefore, the layout problem of large scale rectangular parts converted to layout within group and carrying-on among group. Corresponding cutting layout mathematical model was set up. Five design variables were used to describe layout solution within group. The five variables were directed against layout parts and consisted of number of horizontal row, number of vertical row, quantity of layout parts in each row while be horizontal and vertical respectively, layout direction. Hybrid punishment function that was the combination of interior point method and exterior point one was applied to deal with constrains. GA which made use of binary coding was adopted to solve the model. Feasibility of this method was tested by instance and possible improvement room for the model and algorithm was analyzed.(2) Optimal study on mathematical model of cutting layout and solving algorithm. Two kinds of thinking of improvement about cutting layout problem were presented. The first one was base panel-oriented model which expressed layout solution within group by means of four parameters including quantity demanded for base panel, row layout number of each panel, layout amount and direction of each part in each row. Realization feasibility of GA to this model was analyzed via parameters coding. The second thinking was part-oriented model. In this model, all of parts within one group were taken into account and four parameters that could be stated as which one of part was put on which row of which panel and its layout direction were applied to express layout solution. A grouping and dimension reducing heuristic rule which was based on coupled dimension was put forward. Integer coding method of GA,managing way of constrains were analyzed and adaption algorithm of punishment factors was designed. Feasibility of this model was tested by instance as well.(3) Study on interface file between cutting layout solution and NC program of cutting saw. Writing-in and reading of DXF file was considered and generating method of NC program was established. In order to complete writing-in and reading of DXF file, four steps were set up. In the first step, structure of DXF file and coding method of corresponding segments were studied. In the second step, taking part-oriented model and solution using GA as object, corresponding relationship between layout solution matrix and vertex coordinates of LWPOLYLINE was analyzed aiming at specific instance. Computing method of the vertex coordinates was also put forward. In the third step, writing-in of DXF file was fulfilled under MATLAB. In the fourth step, VC# was applied to read pair of codes, and opening, data extraction and graphic drawing methods of DXF file were explored. Therefore, layout solution could be visualized. On the basis of setting-up and reading of DXF file, generating method of NC program was studied. At first, structure and format of NC program for layout cutting was investigated. Then, four aspects such as design and compute of tool path, choosing of localization datum, division of process and determination of cutting parameters were used to describe cutting process of WBP. At last, generating method and flow path of NC program was presented in detail, further, a kind of software of NC program generation for WBP cutting was designed and tested by instance.(4) Based on hybrid programming of MATLAB and VC#, interface file system between cutting layout solution and NC program was designed by using visual object-oriented method. The whole function structure of the system was established and three basic single functions were divided. The functions were composed of information input, solving and computation, output and results display. Specific realization methods of the basic function models were analyzed. Manual layout system, initialization interface and helping system were set up for the whole system.(5) Application test of cutting layout and interface file system of NC program. Layout data from two types of panel-type furniture were used to test relatively nice performance of optimization algorithm and feasibility of the layout-NC program system. Mainly three aspects including accepting parameters information, operation and solving, generating of layout solution and its visualization as well as interface file were used as testing targets. It was indicated that the system had relatively stable performance and could adapt to layout requirement of preparation section for panel-type furniture.Aiming at optimal layout problem of large scale rectangular parts of wood-based panel, this research proposed a kind of grouping and dimension reducing heuristic rule which was based on coupled dimension, set up part-oriented model and solving algorithm on the basis of GA. Interface files including DXF and NC codes laid the basis for connection between cutting layout solution and cutting saw. It was indicated that the research could provide technical support for layout of panel-type furniture and would have a good application prospect. |
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