Research On Technologies Of Machining Process Planning And Optimization For Three-dimensional Digital Manufcturing

With three-dimensional modeling and simulation replace traditional physical prototype testing,three-dimensional digital manufacturing technologyhas greater technological advantages to improve product quality and reduce production costs.In recent years,it has received the extensive concern of the industry and academia.However,by the traditional 2D drawing-based process design mode influence,three-dimensional digital manufacturing business processes and information management processes are not unified,data transmission is inconsistent.The process decision relies heavily on artificial experience,so,it's hard to ensure the rationality of the technological design.In order to solve these problems,to explore the full three-dimensional digitization process design modeand improve the process design quality as the goal in this paper,drawing on the model based definition(MBD)technology ideas and principles,a process planning and optimization architecture for the three-dimensional digital manufacturing was established.Aiming at machining process,several key technologies,process route decision and optimization based on typical procedure model,procedure design and optimization based on 3D model,virtual machining environment configuration for CAD/CAPP/CAM integration,were systematically explored.The main research work and contributions are as follows:(1)Thetechnology architecture of three-dimensionaldigital process planning and optimization for three-dimensional digital manufacturing was constructed.In order to solvethe problem of inconsistent data transferin the process of three-dimensional digital design and manufacture,a three-dimensional digital machining process planningmodedriven by procedure MBD model was proposed.On this basis,thetechnology architecture of three-dimensional digital machining process planning and optimization wasset up.Take the procedure MBD model as the carrier of information transmission,to avoid the 2D engineering drawing and 3D model of the conversion process,guarantee the consistency of the data transfer.(2)The process route decision and optimization method based on the typical procedue MBD model was proposed.In order to simplify the process sequence planning,combined with the characteristics of three-dimensional digital process planningmode,a new method of process route decision and optimization based on typically procedure MBD model was proposed.In this method,by the match of the machining characteristic and the typical procedue MBD model,the unnecessary decision-making procedures of machining method and machinetools selectionwas reduced,and the process of process sequence planning wassimplified.The feasibility of the proposed algorithm was verifiedby a numerical example.(3)A procedure design and optimization method based on 3Dmodelwas studied.In order to eliminate the impacts of the transition characteristics on the accuracy of process geometrical modeling,a simplified method for transition feature was proposed.This method simplified the transition characteristics by rebuilding the transition feature segments,eliminated the impacts of arc curved surface on geting machining characteristic boundary,thus,guaranteed theaccuracy of procedure models.Usinghypergeometric correlation technology,theprocedure MBD models can be updated automatically,and the workload of proceduremodify can be reduced.In order to ensure the rationality of sequencing machining steps,to shorten the machining time for the target to study the optimization method of sequencing machining steps based on improved genetic algorithm.This method can obtain the global optimal solution in a faster convergence rate,and get the sequencing machining steps which used the least machining auxiliary time.A numerical example was given toverify the availabilityof the proposed method.(4)Avirtual machining environment configuration method for CAD/CAPP/CAM integrated was introduced.To simplify the configuration process of three-dimensional virtual machining environment,a three-dimensional virtual machining environment configuration method based on procedure MBD model was proposed.The virtual machining environment was configurated automatically based on the virtual machining environment configuration template.In order to achieve the optimal allocation of virtual machining environment,a machine tool model optimal configuration method in accordance with the machining capacitywas proposed.Using the interval-valued FCM clustering algorithm to find the optimum configuration of machine tool model,can get rid of the influence of subjective human experience,and ensure the reasonableness of the machine configuration scheme.The feasibility of the proposed algorithm was verifiedby a numerical example.(5)The three-dimensional machining process planning and optimization system was designed and developed.The prototype system of UG-CAPP was designed anddeveloped based on UG/NX7.5 platform,through the integrate applications of TC and UG-CAPP system,three-dimensional digital process planning and optimization was achived.To take a machining process of airplane structure as example,introduced the main fuction module of this system,and verified the effectiveness of the technology and method proposed in this paper.