Rapid development of plastic mold making technology has become an important part of modern manufacturing technology. Such as mold CAD/CAM technology, laser rapid prototyping technology of molds, precision forming technology of molds, ultra-precision machining technology of molds, and dynamics of flow, cooling and heat transfer processes using finite element method and boundary element method in mold design. Simulation technology, CIMS technology for molds, and DTM technology and numerical control technology have been developed, covering almost all modern manufacturing technologies.
Modern mold manufacturing technology is moving in the direction of accelerating information drive, improving manufacturing flexibility, agile manufacturing, and systematic integration.
First, high-speed milling: the third generation of mold making technology
High-speed milling not only has a high processing speed and good machining accuracy and surface quality, but also has a low temperature rise (only 3°C increase in the workpiece) and a small thermal distortion compared to conventional cutting, and is therefore suitable for temperature and thermal deformation. Sensitive materials (such as magnesium alloy) processing; also due to the small cutting force, can be applied to the processing of thin-walled and rigid parts; reasonable selection of cutting tools and cutting amounts, can achieve a series of advantages of hard materials (HRC60) processing. Therefore, high-speed milling machining technology is still a hot topic at present. It has developed to a higher degree of agility, intelligence, and integration, and has become the third generation of mold making technology.
Second, EDM milling and "green" product technology
From the point of view of foreign electric machine tools, the performance, process indicators, intelligence, and automation have reached a very high level. The new trend in foreign countries is the EDM milling technology (electric spark forming technology). The research and development, which is a new technology that replaces the traditional method of forming cavities with a shaped electrode, uses a simple tubular electrode that rotates at a high speed for 3D or 2D contour machining (like CNC milling), so it is no longer necessary to manufacture. Complex forming electrodes, which is clearly a major development in the field of EDM forming.
Recently, Mitsubishi Corporation of Japan has made new progress in the development of the EDSCAN8E EDM machine tool. This machine can automatically compensate for electrode loss, and it is a special CAM system developed for this machine on Windows 95. It can be linked with general-purpose CAD such as AutoCAD, and can perform on-line precision measurement to ensure high-precision machining. In order to confirm whether the processing shape is abnormal or incomplete, the CAM system can also perform simulation processing.
At the same time as the progress of EDM technology, the safety and protection technology of EDM has attracted more and more attention. Many electric machine tools have considered safety protection technology. At present, the European Community has stipulated that machine tools without the "CE" mark cannot enter the European Community market. At the same time, the international market places more and more emphasis on the requirements of safety protection technology.
At present, the main problem of EDM machine tools is radiation harassment because it has a greater impact on safety and environmental protection. As the international market places more and more emphasis on "green" products, it is the leading equipment for die-slotting machining of EDM machines." "Green" product technology will be a problem that must be solved in the future.
Thirth, advanced rapid mold manufacturing technology
1. Rapid development of laser rapid prototyping (RPM) technology. China has reached the international level and gradually realizes commercialization. The rapid prototyping processes that have been commercialized in the world mainly include SLA (stereolithography), LOM (layered separation manufacturing), SLS (selective laser sintering), and 3D-P (three-dimensional printing).
Tsinghua University first introduced the SLA250 (stereolithography or photosensitive resin laser-curing) equipment and technology of the US 3D company and conducted research and development. After several years of hard work, it has improved several times, improved and introduced "M-RPMS-type Functional rapid prototyping manufacturing system" (has layered solid manufacturing - SSM, melt extrusion molding - MEM), which is the only system in the world that has two kinds of rapid prototyping processes (national patents) and has good performance. Price ratio.
2. Dieless multi-point forming technology is another advanced manufacturing technology for sheet metal forming by replacing the traditional die with a height-adjustable punch group. The CAD/CAM/CAT technology is the main method for the dieless multi-point forming system. Realize the automatic shaping of three-dimensional surfaces. Jilin Gongda undertook the national key scientific and technological projects related to moldless molding, and has independently designed and manufactured a multi-mode multi-point forming equipment with international advanced level.
Compared with the Massachusetts Institute of Technology in the United States, the University of Tokyo in Japan, and the Tokyo Institute of Technology in Japan, this technology in our country is in a leading position both in theoretical research and practical application, and is currently advancing toward the promotion and application. 3, resin stamping dies for the first time in the trial production of domestic cars have been successfully applied. FAW Mould Manufacturing Co., Ltd. designed and manufactured 12 sets of resin molds for the modified trial production of the new Little Red Flag sedan. The 12 sets of molds are drawing molds for large-scale complex internal and external covers such as trunks, hoods, front and rear left and right fenders, etc. The main feature is that the mold surface is based on the CAD/CAM main model, the high-strength resin cast by Swiss Ciba is used for the injection molding, the gap between the convex and concave molds is accurately controlled by imported wax chips, and the dimensional accuracy of the mold is high. The cycle can be shortened by one-half to two-thirds, and manufacturing costs can be reduced by about 10 million yuan (12 sets of molds). It has opened up a new way for the trial production and small batch production of cars in China, which is a domestic initiative. Experts of Ciba refinement in Switzerland believe that it can reach the international level in the 1990s.
Fifth, on-site mold testing technology
With the development of precision molds, the requirements for measurement have become higher and higher. Precision coordinate measuring machines have long been limited by the environment and are rarely used at production sites. The new generation of three-coordinate measuring machines basically have temperature compensation and use of anti-vibration materials to improve dust-proof measures, improve environmental adaptability and use reliability, make it easy to install in the workshop, in order to achieve the characteristics of the measurement site .
