Research On Automatic Discharging Method Of 2D Irregular Parts Based On Shaped Sheets

Two-dimensional layout problems are widely found in shipbuilding,sheet metal cutting,furniture assembly,leather garment cutting and other processing and manufacturing industries,and are a typical NP-hard combination optimization problem.In the research of two-dimensional irregular part discharge algorithm,people’s research objects are mainly rectangular complete plates,and there are few researches on automatic discharge of residual materials.The research on the problem of complete sheet material discharge only reduces the generation of residual materials of the board to a certain extent,but it cannot solve the problem of waste material waste.The research direction is to study and realize the automatic nesting algorithm based on the specialshaped sheet.Combining two-dimensional irregular parts in rectangular plate layout research,this paper adopts the main idea of "NFP positioning + genetic algorithm sequencing" to realize automatic layout of two-dimensional irregular parts in shaped plates.The main research contents of this thesis are as follows:(1)Based on the critical polygon is the mainstream method to solve the problem of part positioning.The problem of critical polygon solving is the bottleneck restricting the research of two-dimensional layout.In this paper,the critical collisions of the moving collision method and the Minkowski vector sum method for solving concave polygons are analyzed.The convex segmentation algorithm is used to transform the concave polygon into a simple convex polygon,which makes the critical polygon difficult to solve.(2)In view of the fact that the traditional rectangular plate positioning method does not apply to the special-shaped plate,the inner critical polygon concept is used to solve the problem of irregular part positioning in the profiled plate,and combined with the positioning complexity of the profiled plate parts,the improvement of the traditional positioning method is improved.The improved positioning algorithm not only ensures that the two-dimensional irregular parts meet the constraints during the nesting process,but also considers the possibility of discharging in the void area of the sheet,thereby increasing the utilization rate of the sheet.(3)The genetic algorithm is used to solve the problem of part sequencing optimization,and the details of genetic algorithm implementation are elaborated.According to the experience of the irregular parts in reality,some heuristic strategies are developed to speed up the calculation of the nesting algorithm and optimize the layout results.In addition,a solution to the problem that two-dimensional irregular parts stop discharging in some narrow areas of the profiled sheet is proposed.(4)It is analyzed that the defect area of the profiled plate will affect the positioning of the part during the discharge process,and the original positioning algorithm is improved for this situation.In the multi-part multi-plate automatic discharge material plate sorting problem,this paper proposes a solution based on some emission experience,and verify the effect by example.