Study On The Key Technology Of The Optimum Layout System For Two-dimensional Irregular Figures

The graphic layout technology has been used widely in every industry or trade inchina for its obvious advantages, for which is better to have greater demands from ourindustries. In order to shorten the layout cycle of graphs, reduce the manufacturing costof sheet-metal parts and improve material utilization so that the nesting problem are ableto meet the requirement of the modern market, the nesting algorithm, the keytechnology of graphs’ layout, database technology and secondary development of3Dsoftware are studied in this thesis, and the optimal nesting system for two-dimensionalirregular graphs based on Solidworks is established aiming at the unfolded drawing ofsheet-metal parts.The research contents in this thesis are to layout for two-dimensional irregulargraphs. The main contents of the nesting system are parametric design for the unfoldedgraphs of three-dimensional sheet metal and layout of graphs. The parametric designbased on the unfolded graphs of sheet metal has been completed to draw by the analyticmethod on the Solidworks interface. Based on the parametric design, the structure featureof the expansion plans of sheet metal parts and the nesting process of graphs, the designrequirements of the nesting system of two-dimensional irregular graphs are analyzed, themain function models are determined and the workflow of the system is planned. At thesame time, the development tools and the implementation method are determinedaccording to the requirements of the system and the research conditions.The nesting information model is the information foundation of the nesting systemof two-dimensional irregular graphs. A nesting sequence and angle planning orientednesting information model is established based on the characteristics of expansion plansof sheet metal parts and the layout process, the corresponding information is managed bythe SQL Server database based on Visual Basic. The graphs and layout information canbe expressed completely by the nesting information model. The nesting information canbe obtained from the expansion plans of sheet metal parts through the data extractionmodule of two-dimensional CAD and the information can be regulated and classifiedaccording to requirements of layout.An algorithm for testing function planning based on the mathematics tools ofMatlab and genetic algorithm is applied aiming at the unfolded plans of thethree-dimensional sheet metal parts with curves and holes. In order to make the existingalgorithms more suitable for the nesting sequence and angle planning for nestingtwo-dimensional irregular graphs, the improved operation like selection、crossover and mutation of the basic genetic algorithm are proposed. The layout diagram for actualproduction is generated based on the nesting information model with the nestingsequence and angle planned and the scanning and positioning algorithm.With the addition of analysis of the nesting sub-graph and the stored data alonggraphic layout type, the lowest point can be obtained from margin remaining in the sheetmetal. By judgment the intersection between the sub-graph and the adjacent graph, thefinal location of the sub-graph can be obtained in the sheet metal. The determination ofsub-graph is implemented based on the position scanning algorithm using designing thearranged position of graphs by secondary development of SolidWorks. By addingsub-graph with the nesting sequence and moving the graph based on the relation betweenadjacent figures, all sub-graphs are located. So all graphs layout are achieved.The graphic layout system is implemented based on the Visual Basic.NETdevelopment platform, SQL Server data base technology and secondary development ofSolidWorks. It is a technological support for processing and manufacturing for the sheetmetal parts.