Practical Development Of CAD System Of Porthole Dies For The Hollow Complex Aluminum Profiles

The CAD system of porthole dies regarded as the professional design module of aluminum profiles extrusion can be used to simplify the design processes of extrusion dies, reduce the number of repetitive modeling, and then significantly shorten the design cycle, which has already become a hot research topic in the field of aluminum extrusion. At present, the CAD system of porthole dies is still in the stage of transition from theory to practice. In this paper, the practical development of CAD system of porthole dies will be given a systematic and in-depth study.The design processes and key technologies of porthole dies are investigated and analyzed with the combination of the book ’Design/manufacture/use and maintenance of aluminum extrusion dies’ and the experience handbook from a design company of aluminum extrusion dies. By using the methods of backstepping analysis, the key points of design processes can be determined, and then modulared to build the whole framework of the CAD system of porthole dies. More precisely, the specific design ideas of each module are presented by analyzing the solid modeling approach of die structure, which is of great significance to fulfill the practical development of CAD system of porthole dies.Based on the secondary development language of UG—UG/Open API and UG/Open Grip, each module of CAD system of porthole dies is developed with the idea of step-by-step modeling and this system fulfills the automatic calculation of extrusion process parameters, the standardization and serialization of die dimensions, the modeling of porthole in size/shape/number and distribution, the minimum thickness calculation of bridge, the design of die mandrel and opening of porous profiles, the design of welding chamber and run-out, and the development of drain and baffle plate.The module of extrusion process parameter establishes the database of the extruders and fulfills the automatic calculation of extrusion process parameters. By checking the extrusion ratio and circumcircle diameter of profile, the selected extruder is verified and this module affords reasonable proposals for users, which provides some references for the follow-up design of die structure. The module of bridge design checks the die strength and forwards reasonable proposals of bridge design for users.The module of die dimensions analyzes and discusses three different design methods of standard parts database—parametric design, part family design, as well as UF object design, in which the object problem of UG is particularly emphasized. Part family can be used to deal with operations between parts(assembly) while parametric design is mainly applied to create parts. By contrast, UF object design is usually used for direct modeling which belongs to operations within parts. After that, solid models can be directly operated in Boolean, which undoubtedly meets the requirements of the step-by-step modeling of porthole dies.According to the ideas of gradual design of single porthole, the module of porthole design creates the triangular-shaped porthole and the tetrangular-shaped porthole which almost cover all the porthole shapes. First, the average size of single porthole is calculated, which provides some reference for the following design of porthole. Then, the porthole of any aluminum profiles can be finally designed by integrating the basic functions of UG together into a unit, including the creation of basic curves, coordinate system conversion, extruding and blending. Similarly, the welding chamber of any aluminum profiles can be directly designed by integrating the basic functions of UG, including the function of selection and extruding. By setting the coefficient of linear expansion in the dialog box, the die mandrel and opening of any aluminum profiles can be directly fulfilled by integrating the functions of selection, scaling and extruding.The CAD system of porthole dies preliminarily fulfils the design of porthole dies for any hollow profiles and the merits of this system are as follows:(1) The practical development of this system satisfies the design of any hollow profiles;(2) Based on the knowledge and experience design, knowledge is incorporated into the system by human-computer interaction, which initially achieves the intelligent design of porthole dies;(3) By analyzing the characteristics of modeling, the basic functions of UG are integrated, as well as the knowledge and experience are packaged, which suffice the needs of users who have different skill levels.The aluminum profile used as the sidewall panel in the high-speed train is preliminarily designed in the developed CAD system, and then, analysis model is created and numerically simulated in the CAE software—HyperXtrude. By analyzing the velocity, stress and temperature distribution of aluminum alloy in the extrusion process, the structure of porthole die is optimized, which reduces the number of testing and repairing die, shortens the production cycle of porthole die, and then provides some theoretical guidance for the actual production.