Research on die casting process and die CAD system
Abstract: according to the object-oriented idea, the design framework of die casting process and die CAD system is discussed, and the implementation mode of CAD system is given
key words: Die Casting; CAD； Object oriented design
die casting process and its die CAD system can shorten the design cycle, reduce the cost and improve the competitiveness of products, which has been widely valued at home and abroad. At present, there are mainly two system development methods that continue to provide new material solutions for household appliances. One is based on general mechanical CAD/CAM software, such as UG and pro/engineer in the United States; The other is to compile the CAD core program according to the visual programming language under Windows environment, and the components outside the core program are developed by other professional software. For example, most of the graphics processing functions are completed by AutoCAD. For the majority of small and medium-sized users, the software and hardware investment of the latter method is low, which can be regarded as an economic, practical and effective development method. This research adopts this development method
1 hierarchical relationship and design framework between die casting process and die CAD system objects
the construction process of die casting process and die CAD system is completed according to the hierarchical relationship structure between design objects. The transmission of messages between objects and the invocation of parameters are completed by triggering menu events on the system visual interface. The ultimate goal of the system is to design a set of die-casting tools, so the design work is completely based on each component of the die-casting mold (i.e. the object) as the core. Die casting process design is used to realize each (sub) process of message transmission between objects, which is embodied by writing operation process code. As for the description and constraints of the object itself, it is realized by defining each attribute variable of an object and assigning constraints to it. Of course, the implementation of assignment depends on the transmission of messages between objects. In this way, an object-centered design idea is established in the project, and the objects are connected through the message passing mechanism (menu driven event occurrence process description). Figure 1 shows the hierarchical relationship of die casting CAD system based on object-oriented idea
Figure 1 hierarchical relationship of die casting CAD system
the overall design framework of die casting process and die intelligent CAD system is shown in Figure 2
Figure 2 overall design framework of die casting CAD
because the object-oriented idea runs through the whole die casting process and die design process, the object-oriented relational database has a good connection with the design process. In addition, the application of object-oriented method is not limited by specific database format types, which enhances the flexibility of its application and the convenience of its implementation, and can effectively support the whole design process of complex object system
2 the realization of intelligent CAD system for die casting process and its die
2.1 design of gating system and exhaust duct. In this way, a coding vector  can be input to the neural network. Through the forward operation of the neural network (which has been trained by the sample mode), an output vector can be obtained. After weighted average, it can be reduced to a desired chamber injection pressure. Under a certain set of molds and die-casting machines, the actual chamber injection pressure is only affected by the index of the air injection speed of the pressure casting machine. Therefore, by adjusting the opening of the speed valve by adjusting the injection mechanism, the air injection speed can be changed to adjust the actual injection pressure and achieve the expected value of neural network simulation
after clicking the "neural network simulation" option in the "gating system" main menu, the neural network simulation visualization interface pops up (Fig. 3)
after clicking the "pouring process parameters" option in the "gating system" main menu, the "gating system design" visual interface pops up. According to the selection of relevant process parameters of die casting alloy and die casting machine, the system can automatically calculate the process parameters of gating system
after clicking the "exhaust duct" submenu, the "exhaust duct design" visual interface pops up (Figure 4)
2.2 process check
process check is realized by tab. For example, when checking the mold locking force of the die-casting machine, when the type of die-casting machine is selected in the check box of Dale Brosius, chief commercial officer of iacmi, the automatic shielding of other types of die-casting machines is realized. When the "the first mock examination with multiple cavities" check box is selected, a dialog box pops up, and the user can input the number of cavities per mold through human-computer interaction (Fig. 5)
2.3 mold cavity forming dimension design
when the user clicks the "center distance" radio button, there is no wear or mold repair problem, so the "mold repair coefficient" is automatically shielded in the design results. When it is necessary to make corrections, the relevant information prompt box will pop up automatically (Fig. 6)
2.4 generation of process drawings
process drawings include mold assembly drawings, mold insert part drawings, and module part drawings. AutoCAD application software control, measurement and operation can be programmed by visual language to realize the generation of process drawings. AutoCAD is designed as a general drawing system. In order to meet the needs of mold CAD system development, AutoCAD must be customized according to the open architecture provided by AutoCAD application software system, combined with the specific technical specifications and standards in die casting process and mold design. Here, according to the ActiveX Automation Programming Environment of AutoCAD, we have compiled the AutoCAD Application Interface Based on the client/server object model. This makes Jinan new era Gold Testing Instrument Co., Ltd. sincerely escort your work, and the visual language for customers can manipulate various objects implemented in the server AutoCAD, so as to generate and process various graphics. Most of the attributes and methods of these objects implemented in AutoCAD can be exposed to the visual programming language in the automation environment, that is, the methods of AutoCAD objects have become external public member functions provided to customers, and their attributes have also become a public data field. In this way, the task proposed to the developer is essentially to use the visual programming language to assign and modify the attributes of these objects and call various methods on the basis of being familiar with various object attributes and methods of AutoCAD. Figure 7 shows the die casting die assembly drawing generated by the system
the design framework and implementation method of die casting process and die CAD system based on object-oriented thinking studied in this paper mainly consider the intelligence, hierarchy and realizability of the design. At the same time, in order to realize the real parametric design, the standardization and database of design process are required, and the design standard of die-casting mold must be established. In the future, great efforts should be made to strengthen this work
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