A Learning Reuse Algorithm Of Fixture Design Based On Minimum DFS Coding

In the process of the enterprise,the first problem is the workpiece clamping,which directly affects the quality of the product.That is to say,the quality and efficiency of fixture design directly affect the quality and efficiency of product.In manufacturing,the enterprise is pursuing the lower cost,better quality and higher efficiency.In this way,they can survive and develop in the global market competition.In the whole process,the fixture design time accounts for about 35%-50% of the whole processing cycle,it is very important to shorten the processing cycle from the improvement of the fixture design efficiency.However,the traditional fixture design is the most typical analogy method and empirical method,these methods are not only high cost,low efficiency,and the use of fixture and its limited scope.It is difficult to meet the requirements of small batch and multi varieties,and it is difficult to meet the requirements of CAD/CAPP/CAM integration.In addition,modern machining workpiece size,positioning accuracy and poor coordination,easy deformation often occurs,which makes the work more difficult fixture design.Therefore,to break the traditional way of thinking,to explore new efficient fixture design method is imminent.A numerous of fixture cases can supply reusable experience and knowledge for fixture design.They are basis of achieving rapid fixture design.However,the accurate search a fixture from fixture cases is core and key to the achievement of fixture rapid design.Therefore,based on the entity boundary representation(B-Rep)model of a workpiece,the labeled graph of workpiece is constructed according to the geometrical and topological relationships between features.In combination with the linear sequence and scalable continuity of labeled graph,the determination principles of labeling a feature is proposed for the traversal flowchart of the minimum DFS code.For the minimum DFS code of a new workpiece and workpiece set for fixture cases,a mining method of their subgraphs is produced.Furthermore,on the basis of similarity of workpiece and similarity of fixture graph set,a judgment criterion of the maximum isomorphism subgraph is presented to select a fixture.Finally,the theoretical and manufacturing conditions of locating determination is established for the exact matching between a new workpiece and fixture graph set so that a fixture can be rapidly design for a new workpiece.