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Mold CAD/CAE/CAM is a key technology for transforming traditional mold production methods. It is a high-tech, high-efficiency system engineering. In the form of computer software, it provides enterprises with an effective auxiliary tool to enable engineers and technicians to design and optimize product performance, mold structure, forming process, numerical control processing, and production management by means of computers. Die CAD / CAE / CAM technology can significantly shorten the mold design and manufacturing cycle, reduce production costs and improve product quality has become the mold industry consensus.
As with any new thing, mold CAD/CAE/CAM has gone through the process from simple to complex, from pilot to universal in the last two decades. Since the beginning of this century, mold CAD/CAE/CAM technology has developed faster and has a wider range of applications. In order to enable the mold workers to further deepen the understanding of the technology and better play the role of mold CAD/CAE/CAM, this article The general introduction and analysis of the most widely used and representative casting molds, forging dies, progressive dies, automotive cover molds, and plastic injection molds CAD/CAE/CAM development status and trends.
Development of Casting Die CAD/CAE/CAM
The exploratory work of the casting forming process simulation began with solving the temperature field distribution of the casting. In 1962, Fursund of Denmark first used the finite difference method to calculate the heat transfer during the solidification process of two-dimensional castings. In 1965, Henzel of the United States General Motors successfully simulated the temperature of the turbine castings, and then the castings were in the mold cavity. The heat transfer process numerical analysis technology is rapidly carried out throughout the world. From the 1970s to the 1980s, the United States, Britain, France, Japan, and Denmark have made remarkable achievements in the solidification simulation research and application of castings, and have successively launched a number of commercialization simulation software. After entering the 1990s, our universities, such as Tsinghua University and Huazhong University of Science and Technology, have also achieved remarkable achievements in this field.
The simple simulation of heat transfer process can not accurately calculate the temperature variation of the casting and predict the possible defects in the casting. The influence of the filling process on the distribution of the initial temperature field of the casting and the influence of the flow of the liquid metal on the formation of the casting defects in the solidification process are all It cannot be ignored. The simulation technology of the filling process of castings began in the 1980s. Based on theories and methods of computational fluid dynamics, it took more than ten years to begin with two-dimensional simple shapes, gradually deepen and expand, and has now successfully realized three-dimensional complexity. The filling process of the shape casting is simulated and the flow and heat transfer process can be coupled. At present, there are a number of commercially available three-dimensional casting process simulation software, such as SOLIDIA in Japan, SOLSTAR in the United Kingdom, SIMULOR in France, NOVACAST in Sweden, MAGMA in Germany, AFSOLID in the United States, and PROCAST in the United States. There are also foundry stars of Tsinghua University and Huacai CAE of Huazhong University of Science and Technology. These casting die CAE software has covered castings such as cast steel, cast iron, cast aluminum, and cast copper, ranging from hundreds of tons to as little as several kilograms, both in the elimination of shrinkage and shrinkage, and in the optimization of pouring riser designs. Improving slag inclusions and other aspects have played a significant role.
With the successful application of CAE technology in the foundry field, the research and application of the casting process and mold structure CAD are also deepening. Some foreign applications have been introduced successively, such as AFS-SOFTWARE of the American Foundry Association, which can be used for cast steel and cast iron. The riser design of the parts, the FEEDERCALK software of FOSECO of the United Kingdom, can calculate the size of the riser for cast steel and the type of insulated riser. China Huazhong University of Science and Technology and Tsinghua University have also done a lot of work in casting process and mold structure CAD, such as the TLESCAD software developed by Tsinghua University, mainly composed of two parts: the pattern scanning and vectorization and the casting process CAD. The former part of the scan input graphics decontamination and decontamination and vectorization, the latter part is used to create parametric graphics, calculate the machining allowance of the casting, drawing process cards. THFSCAD is developed on the basis of 2D graphics and uses AUTOCAD software as a development platform. With the rapid advancement of CAD technology, 3D CAD systems will gradually replace 2D CAD systems in the field of casting production and become mainstream design systems.
Development Overview of Forging Die CAD/CAE/CAM
Since the 1970s, many academic institutions and companies at home and abroad have conducted extensive research on forging die CAD/CAE/CAM technology, and achieved remarkable results in forging process design, forging die structural design, and metal flow simulation. Achievements.
Axle-symmetrical forgings account for about 30% of the total number of forgings, and the axisymmetrical forgings have simple geometry and are easy to describe and define. Therefore, most institutions and people at home and abroad are developing axes-symmetrical forging dies when developing forging die CAD/CAM systems. . The main components of the axisymmetric die forging CAD/CAM system include forging design, die forging process design, forging die design and NC programming. Forging design refers to the design of cold forging drawings and hot forging drawings, including the selection of the parting surface, supplementary machining allowances, fillets, and draft angles. The forging process design determines whether to use the preforming process, how to use the preforming process and how to select the tonnage of the forging equipment.
The other widely used forgings are long shaft forgings, and their forming process design and die structure design are far more complicated than axisymmetric die forgings. Therefore, it is more difficult and less versatile to develop long axis forging die CAD/CAM systems. Currently, CAD/CAM systems for long axis forging dies developed on many general-purpose commercial CAD/CAM software are limited to specific products and applications for specific occasions. The development direction of forging die CAD/CAM systems is group technology and Further implementation of mold standardization technology and in-depth application of CAE technology and artificial intelligence technology.
In terms of CAE technology, the finite element method has been the main numerical analysis method for analyzing and studying the formation of metal forgings. Over the years, many results have been achieved. In 1973, Lee and Kobayashi used the matrix analysis method to derive the Lagrange algorithm of rigid plastic finite element, and successfully analyzed the forging process. In 1974 Zienkiewicz proposed a rigid viscoplastic finite element method for the penalty function and analyzed the forming processes such as rolling, extrusion and drawing. In 1982 Mori and Osakada proposed a material compressibility method in rigid plastic FEM for rolling and extrusion. In the early 1980s, Oh and Altan used the large rigid-plastic finite element analysis software ALPID to conduct in-depth research on various plastic deformation problems. After the 1990s, some commercial specialized finite element analysis software, such as French FORGE2, American DEFORM, ABAQUS, MSC/AutoForge, etc., have been successfully applied in forging. These software can not only predict the whole process of forging forming, but also quantitatively give various physical quantities related to deformation, such as displacement, velocity, stress, strain and load, etc., in order to obtain the optimal mold design and the most reasonable process scheme. And the minimum test time provides technical assurance.
Progress of Progressive Die CAD/CAE/CAM
The research of foreign progressive die CAD/CAE/CAM began in the late 1960s and was initially applied in the 1970s. However, it was limited to the simple blanking and progressive die of 2D graphics. The main functions of the die were blanking and concaves. Die layout, process calculations and NC programming. The curved progressive die CAD/CAM system appeared in the 1980s, such as the bending progressive die system of Hitachi, Japan and Fujitsu. In order to be able to adapt to the design of complex molds, the Fujitsu system uses a combination of automatic design and interactive design. In this system, except for billet unfolding, bending springback calculation, and step sequencing, the designers need to participate. .
The progressive die system using three-dimensional geometric modeling technology began in the late 1980s, such as the Die-Design system of Auto-trol in the United States. The system uses three-dimensional geometric models to describe sheet metal parts, and applies three-dimensional graphics technology to the die structure design. , Shows the important role of 3D graphics software in mold design.
Into the 90s, the internationally renowned commercial three-dimensional CAD/CAM systems, such as the United States Pro/E, UG-II, CADD5, Solidworks, MDT, etc. have been applied in the mold industry. U.S. PTC developed Pro/Sheet Metal, a sheet metal part modeling module, based on the Pro/E system. UG Solution Company developed the same type of module UG/Sheet Metal based on UG-II. Both of the above two systems lack specialized modules that are designed to advance the forming process and die structure design. However, the work in this area has progressed rapidly and some have achieved initial success.
For instance, Striker Systems, a progressive die software developed by Computer Design, is a commercial CAD/CAM system with large sales volume, including SS-DESIGN, SS-UNFOLD, and blank layout (SS). - STRIP DESIGN), SS-DIE DESIGN and CNC machining (SS-WIRE, SS-PROFILE) modules. The system supports the feature modeling of sheet metal parts. Although it has some functions of automatic design, the design process is still based on interactive operation. At present, it is only applicable to the design of bending blanking progressive die.
At the beginning of this century, UGS Co., Ltd. and Huazhong University of Science and Technology in China jointly developed a progressive CAD/CAM software NX-PDW based on the 3D geometric model on the UG-II (now NX) software platform. The software includes modules for project initialization, process pre-definition, blank development, blank layout, waste design, strip layout, pressure calculation, and mold structure design. With distinctive features such as feature recognition and reconstruction, and full three-dimensional structural correlation, it has been put into the market as a commercial product in 2003. Since the 1990s in China, Huazhong University of Science and Technology, Shanghai Jiaotong University, Xi'an Jiaotong University and Beijing Institute of Mechanical and Electrical Technology have successively carried out research and development of progressive die CAD/CAM systems. For example, the State Key Laboratory of Mould Technology of Huazhong University of Science and Technology developed a feature-based progressive die CAD/CAM system HMJC on the AutoCAD software platform, including sheet metal part feature modeling, feature-based stamping process design, die structure design, and standard parts. Typical structure library tools and wire cutting automatic programming five modules. Shanghai Jiaotong University developed a successful punching and progressive die CAD/CAM system for Finetool Fine Finish in Switzerland. Xi'an Jiaotong University has developed a multi-station bending progressive die CAD system. In recent years, some domestic software companies have also competed in the development of progressive die CAD/CAM systems, such as the CmCAD progressive die system developed by Shenzhen Yaming Software Production Studio and the CAD system developed by Foxconn for single die and composite die. Fox-cad et al.
Development Overview of Automotive Cover Mold CAD/CAE/CAM
The earliest international research and development of car cover mold CAD/CAM system is the major automobile manufacturing companies. As early as 1965, Japan's Toyota Motor Corporation had applied CNC technology to the mold processing of automotive panels and achieved very good economic results. The car cover CAD/CAM system adopted by Toyota Motor Corporation in the 1980s includes two design softwares, NTDFB and CADETT, and TINCA software that processes convex and concave molds. It can complete the body shape design, body structure design, die CAD, and master Models and tasks such as die machining and jig processing. According to reports, after the system is put into use, Toyota can reduce the time required for the design and manufacture of automobile panel forming dies by 50%. At the beginning of this century, Toyota Motor Corporation adopted the development oriented drawing system based on the Pro/E software platform developed by PDC of the United States. Die design professional software Pro/Dieface.
U.S. General Motors relies on UGS of the United States to develop special modules for automotive panel mold design on the UG-II software platform, such as sheet metal part design, body design, stamping process design for overlay parts (including stamping direction selection, The addition of process margin, the design of the shape of the blanking surface, and the determination of the trimming line, and the design of the die structure are currently in the trial operation stage. At the same time, companies such as Ford Motor Company of the United States, PSF Corporation of the United Kingdom, Japan’s former Iron Works, Fuji Iron Works, etc., which produce automotive panel molds, have also developed CAD/CAM systems for automotive cover modules for their respective companies. Currently these systems are not yet available for sale.
Domestic companies such as Hunan University, Jilin University, and Huazhong University of Science and Technology have conducted systematic and in-depth research on CAD/CAE/CAM technologies for automotive panels in recent years, and have achieved many promising results.
For example, Hunan University uses advanced punching CAE technology as a breakthrough to develop a series of software including stamping process design and automotive panel mold design and manufacturing. Its stamping simulation CAEM automatic modeling system CADEM-I can use the numerical control trajectory data of the mold surface as the geometric data source generated by the grid, so that the modeling efficiency can be doubled and the simulation model can be made with the same accuracy for the automotive panel forming. The grid unit is reduced by nearly 20% to 40%. The stamping simulation CAE system CADEM-II adopts advanced theories and algorithms to significantly increase the analysis speed under the premise of guaranteeing the large deformation accuracy of stamping parts. The stamping process analysis and design system CADEM-III uses the shell instability theory to predict the wrinkling trend in the forming of the cover. The back-calculation technology based on simulation is used to realize the iterative reverse of the blank shape and size of the complex parts.
Another example is FASTAMP, a rapid analysis software for automotive panel stamping formed by the State Key Laboratory of Die & Mold Technology, Huazhong University of Science and Technology. Based on the improved finite element inverse algorithm and plate and shell unit, the friction, blank holder force and drawing ribs are taken into consideration. Conditions, which closely link product design, material selection and process design, can quickly simulate defects such as wrinkling, cracking and under-formation after car cover forming, optimize the blanking force, draw ribs and friction and other process parameters, and check The rationality of the pressing surface and the supplementary surface of the process and the provision of an optimal blank shape can provide a comprehensive solution for the process design and mold design of automotive panels.
Development of Plastic Injection Mould CAD/CAE/CAM
Plastic injection mould CAD/CAM is continuously deepened with the development of general mechanical CAD/CAM technology. From the CAD system based on the wireframe model in the 1960s to the CAD/CAM system with the surface modeling in the 1970s, the successful application of the solid modeling technology in the 1980s, and the parametric solid/surface modeling technology based on features in the 1990s. Perfection, providing a reliable guarantee for the use of CAD/CAE/CAM technology for plastic injection moulds. At present, a number of CAD/CAE/CAM systems that have been successfully used in plastic injection molds have emerged in the domestic and foreign markets.
Nowadays, some famous commercial three-dimensional modeling software abroad have independent injection mold design modules, such as Pro/E from PTC Company, UG-II from UGS Company, and I-DEAS System from SDRC Company. The three CAD/CAM systems are currently the most widely used in the plastic mold industry. In addition, there are the CADDS system of American CV, the EUCLID system of French MATRA, the CATIA system of French DASSAULT, the DUCT system of British DELCAM, the Space-E system of Nippon Shipbuilding Information Systems, and the CADCEUS system of UNISYS, Japan All have their own characteristics, have their own user base.
The development of plastic injection moulding CAE technology is also very rapid. The application range has been expanded from one-dimensional flow and cooling analysis in the 1960s to 2D flow and cooling analysis in the 1970s to quasi-3D flow and cooling analysis in the 1990s. To the pressure analysis, fiber molecular orientation and warpage prediction and other areas with outstanding results.
The most widely used plastic injection molding CAE commercial software is the simulation software MF of Moldflow Inc., which includes flow simulation (MF/FLOW), cooling analysis (MF/COOL) and warpage analysis (MF/WARP). Gas-assisted analysis (MF/GAS) and stress analysis (MF/STRESS). In 1998, the company launched a quasi-three-dimensional two-dimensional flow software (Part Adviser). In 2002, it launched a true three-dimensional entity flow software module. At present, the company has a large user base in the world.
In the past ten years, China has conducted systematic and in-depth research on plastic injection molding CAE technology. Huazhong University of Science and Technology, Shanghai Jiaotong University, Zhengzhou University, and Nanchang University have all achieved encouraging results. For example, HSCAE6.10, a commercial plastic injection molding integrated simulation system recently launched by the State Key Laboratory of Die & Mould Technology at Huazhong University of Science and Technology, has undergone the process from 2D analysis to 3D, from the HSCAE 1.0 version released in 1989 to the current 6.10 version. The analysis, from practical use to commercialization, from the local pilot to the large-scale promotion and application process, has become a powerful tool for plastic product design, mold structure optimization and engineer training. The HSCAE simulation system is currently being promoted in more than 80 factories and schools in China. application.
Development trend of mold CAD/CAE/CAM
This century's science and technology are undergoing rapid changes. Through the close integration with computer technology, a series of technological developments related to the mold industry, such as artificial intelligence technology, concurrent engineering, assembly-oriented, parametric feature modeling, and associated design, etc. The unprecedented cross-cutting of fields and disciplines has never been seen before. The new generation of mold CAD/CAE/CAM systems in the next ten years will inevitably be the product of today's best design concepts, the latest forming theories and the highest level of manufacturing methods. Its characteristics will be reflected in the specialization, networking, and integration. Four aspects of intelligence.
With the rapid development of the mold industry, software developers in various countries in the world have invested huge human and material resources in recent years. According to the characteristics of various types of molds, the general CAD/CAM system has been transformed into a dedicated system for the mold industry. Great results. Has been put into use UGS United States Progressive Die Design System NX-PDW, Plastic Injection Mold Design System Mold Wizard, Israel Cimatron's mold design and manufacturing system Quick, UK DELCAM's plastic mold design and manufacturing system PS-Moldmaker , France, Misslel software injection mold software Top Mold and Progressive Die special software Top Progress, Japan's UNISYS plastic mold design and manufacturing system CADCEUS and so on. The technical characteristics of these softwares are the ability to use a unified database to complete the design of a specific mold in a unified system environment. NX-PDW initially implemented the structural relationship of mold parts. CADCEUS featured the linkage between 3D design and 2D view. PS-Moldmaker did automatic packaging of processing information. These features made professional software more user-friendly.
At present, some foreign software developers have been able to divide the product series according to the functions in the actual production process, realize the integration of CAD/CAE/CAM under the network system, and solve the problem that traditional hybrid CAD/CAM systems cannot meet the actual production process. Claim. For example, based on the original software DUCT5, the DELCAM company in the UK introduced Delcam's Power Solution, a CAD/CAM integrated system, to meet the latest software development and industrial production. The system covers geometric modeling, reverse engineering, industrial design, and engineering drawing. Simulation analysis, rapid prototyping, data programming, measurement analysis and other fields. Each functional module of the system can operate independently, and can be compatible with other systems through data interfaces, and can be combined according to the use requirements, so as to form a specialized CAD/CAE/CAM system, so as to be open and compatible. The unification of specialization. It can be expected that the die CAD/CAE/CAM system will gradually develop into an integrated system that supports product information management from design, analysis, management, and processing throughout the next few years.
At this stage, mold design and manufacturing still depend to a great extent on the experience of the molder. Only the computer's numerical calculation function is used to complete the selection of mold design solutions, optimization of process parameters and mold structure, and diagnosis of molding defects. The evaluation of mold forming performance is unrealistic. The new generation of mold CAD/CAE/CAM systems are using KBE (Knowledge Based Engineering) technology to transform their bones. For example, the artificial intelligence module KF (Knowledge Fusion) provided in UG-II. Using KF can incorporate design knowledge into the system for pattern recognition and reasoning.
The combination of numerical computation and artificial intelligence technology will be a very difficult and important task for a long time to come. The traditional simulation software is basically a passive calculation tool. Before the analysis, the user needs to design the forming scheme and determine the process parameters in advance. The analysis results are often difficult to directly use to guide production. This greatly affects the promotion and popularization of simulation software. The State Key Laboratory of Mould Technology of Huazhong University of Science and Technology has successfully introduced artificial intelligence technology in domestic injection molding simulation software HSCAE6.10. For parameters such as injection time and injection temperature, which have a continuous value space, artificial neural networks are used for optimization. The interpretation and evaluation of the analysis results are based on rule-based reasoning. HSCAE 6.10 expert system rule base is based on expert knowledge and covers areas related to short shot, flow balance, melt degradation, temperature difference control, holding time, allowable shear stress, shear rate, and clamping force. Knowledge, based on the synthesis and refinement of the analysis results, drives the expert system to reason, evaluates the molding solution, and outputs specific suggestions for improvement in the analysis report. The goal is to enhance the simulation software from traditional “passive†computing tools. For the new generation of "active" optimization system.
Mold CAD/CAE/CAM Technology
introduction