Research On CNC Cutting System Graphic Processing Optimization Algorithm

CNC system is widely used in the production and processing of various industries. As one of the important parts in the CNC system, the graphic layout will affect the cost of the production materials and the efficiency of the subsequent cutting process. This paper makes a deep research on the graphic layout problem that given graphics nesting on a plate, of which the width is determined but the height is unlimited. To reduce the used height of plate and improve the utilization rate of materials, this paper respectively study on three stages of graphic layout, namely preprocessing of irregular graphics, solving of the layout order, nesting of the graphics one by one. Through triangular preprocessing algorithm simplifying the irregular shapes layout, genetic-tabu search algorithm searching the best graphic layout sequence, combined contour algorithm finding graphic optimal placement and calculation placed coordinate graphics, the graphic layout algorithm get optimized.(1) Establish the mathematical model of rectangular nesting problem. Analyze the significance of the search strategy and the advantages and disadvantages of genetic algorithm and tabu search algorithm. To solve genetic algorithm premature convergence problem, tabu search algorithm is used in the mutation process of genetic algorithm, linking undetermined ranking problem, the coding, decoding, crossover, mutation processes of genetic algorithm and the neighborhood search and the number of iterations processes of tabu operator, and tabu list length parameter are designed. The simulation the comparison with genetic algorithm was carried on. The results show that the genetic-tabu algorithm has better search efficiency and ability to break through the local optimal solution, but its ability to approximate the optimal solution is not much different from the genetic algorithm.(2) Analysis the significance of the layout strategy and commonly used graphics layout strategy, including BL, step-down, BLF, the lowest horizontal line four algorithms. Aiming at overcoming the shortcomings of the lowest horizontal contour line algorithm, that contour line length decreases during nesting, improvement is made to this algorithm, adjacent contour with same or similar height were combined before every rectangular nesting, after the rectangular nesting all combined contour lines recovery to two contours. The combined contour algorithm were applied to sequencing nesting and non sequencing packing problem, simulation and comparing was carried on multiple samples with the lowest horizontal contour line. Simulation results show that the combined contour algorithm can use less height of plate when nesting.(3) For irregular graphics layout problem, aiming at solve the shortage of the smallest rectangular envelope algorithm, of which envelope rate is low, the triangular envelope algorithm of convex polygons is put forward. And combined with the smallest rectangular envelope algorithm, the triangle preprocessing algorithm is proposed, which based on envelope, classification, combination three aspects. It simplified packing problem of convex polygon. The algorithm is applied to uncertain sequence packing problem, simulation and comparison was conducted on a random sample with the smallest rectangular envelope algorithm. Simulation results show that the triangle pretreatment algorithm using smaller height of plate.