In the development of automotive die industry at home and abroad, die technology shows the following trends.
I. The simulation of stamping process (CAE) plays a more prominent role.
In recent years, with the rapid development of computer software and hardware, the simulation technology of stamping process (CAE) plays an increasingly important role. In developed countries such as USA, Japan and Germany, CAE technology has become a necessary link in the process of die design and manufacture. It is widely used to predict forming defects, optimize stamping process and die structure, improve the reliability of die design and reduce the time of die test. Many domestic automotive die enterprises have also made remarkable progress in the application of CAE and achieved good results. The application of CAE technology can greatly save the cost of test die and shorten the development cycle of stamping die. It has become an important means to ensure the quality of die. CAE technology is gradually transforming die design from empirical design to scientific design.
2. Consolidation of the Position of Three-Dimensional Design of Dies and Moulds
The three-dimensional design of die is an important part of digital die technology, and is the basis of realizing the integration of die design, manufacturing and inspection. Toyota Japan, General Motors USA and other companies have achieved three-dimensional die design, and achieved good application results. Some foreign practices in the three-dimensional design of dies and moulds are worthy of our reference. In addition to facilitating integrated manufacturing, the other advantage of three-dimensional die design is that it is convenient for interference checking and motion interference analysis, which solves a difficult problem in two-dimensional design.
3. Digital Mould Technology has become the Mainstream Direction
In recent years, the rapid development of digital die technology is an effective way to solve many problems in the development of automobile die. The so-called digital die technology is the application of computer technology or computer aided technology (CAX) in the process of die design and manufacture. Successful experience of applying computer aided technology in domestic and foreign automotive die enterprises is summarized. Digital automotive die technology mainly includes the following aspects: (1) Manufacturability design (DFM), that is, considering and analyzing manufacturability in design to ensure the success of process. (2) The auxiliary technology of die surface design and the development of intelligent technology of die surface design. (3) CAE aided analysis and Simulation of stamping process, prediction and solution of possible defects and forming problems. Fourthly, the traditional two-dimensional design is replaced by three-dimensional die structure design. CAPP, CAM and CAT technology are used in the manufacturing process of the die. _Under the guidance of digital technology, the problems in the process of die testing and stamping production are solved.
4. Rapid Development of Mold Processing Automation
Advanced processing technology and equipment is an important basis for improving productivity and ensuring product quality. It is not uncommon for advanced automotive die enterprises to have CNC machine tools with double worktables, automatic tool changer (ATC), photoelectric control system for automatic machining and on-line measurement system for workpieces. NC machining has developed from simple surface processing to comprehensive processing of surface and structure, from low-speed processing to high-speed processing, and the processing automation technology has developed rapidly.
5. Stamping Technology of High Strength Steel Plate is the Future Development Direction
The use of high strength steel in automobiles is increasing because of its excellent properties in yield ratio, strain hardening, strain distribution and impact energy absorption. At present, the high strength steels used in automobile stamping parts mainly include paint hardening steel (BH steel), dual phase steel (DP steel), transformation induced plasticity steel (TRIP steel), etc. The International Ultra-Light Body Project (ULSAB) predicts that 97% of the advanced concept vehicle models (ULSAB-AVC) launched in 2010 will be made of high strength steel. The proportion of advanced high strength steel sheets in vehicle materials will exceed 60%, and the proportion of dual phase steel sheets will account for 74% of vehicle steel sheets. Now a large number of soft steel series, mainly IF steel, will be replaced by high strength steel plate series, and high strength low alloy steel will be replaced by dual phase steel and ultra high strength steel plate. At present, the application of high strength steel plate for automotive parts in China is mostly confined to structural parts and beam parts, and the tensile strength of the materials used is more than 500 MPa. Therefore, grasping the stamping technology of high strength steel plate quickly is an important problem to be solved urgently in China's automobile die industry.
6. Promotion of new mould products in time
With the development of automobile stamping production efficiency and automation, progressive die will be more widely used in the production of automobile stamping parts. Stamping parts with complex shapes, especially small and medium-sized complex stamping parts which need multi-pairs of punching dies in sequence according to traditional technology, are increasingly formed by progressive dies. Progressive die is a kind of high-tech die product, which is difficult in technology, requires high manufacturing accuracy and has a long production cycle. Multi-position progressive die will be one of the key die products in China.
7. Mould material and surface treatment technology will be reused
The quality and performance of die materials are important factors affecting die quality, life and cost. In recent years, in addition to a variety of high toughness and high wear resistance cold-working die steels, flame quenching cold-working die steels, powder metallurgy cold-working die steels introduced, the selection of cast iron materials in large and medium-sized stamping dies abroad is a trend worthy of attention. Ductile iron has good strength, toughness and wear resistance. Its weldability, machinability and surface hardening properties are also good, and its cost is lower than that of alloy iron. Therefore, it is widely used in automobile stamping dies.