The development direction of mold design and processing technology

Continuously improve EDM's efficiency, degree of automation, and processed surface integrity;

* Precision and large-scale EDM equipment;

* EDM equipment processing stability, easy operation and excellent cost performance;

* Research and development of new types of pulse power sources such as high-efficiency energy-saving and anti-electrolysis to meet different requirements, power waveform detection, and processing and control technology development;

* Further development of high-performance integrated technical expert system and continuous development of EDM intelligent technology and adaptive control, fuzzy control, multi-axis linkage control, automatic electrode exchange, automatic double-line switching, anti-electrolytic action and discharge energy distribution and other technologies development of;

* Development of mirror bright processing technology such as mixed powder processing;

* The development of micro-EDM technology, including three-dimensional fine-grained CNC EDM milling and micro-EDM grinding and micro-EDM technology;

* The use of artificial intelligence technology in WEDM, the advancement of wire walking systems and threading technology;

* EDM milling technology and machine tools and EDM machining centers (including molding machines and wire cutting machines) will be developed;

* As a sustainable development strategy, green EDM technology is an important development trend in the future.

The biggest competitive factor in the future of rapid prototyping (RPM) and rapid tooling (RT) technology is how to quickly produce the molds that the user needs. RPM technology can be used directly or indirectly for RT. The goal of rapid metal mold manufacturing technology is to directly manufacture high-precision durable metal molds that can be used in industrial production. The key technology of indirect method is to develop short process technology, reduce precision loss, low-cost lamination and integration of surface finishing technology. The combination of RPM technology and RT technology will be the direction of further development of traditional rapid molding techniques (such as middle and low melting point alloy casting, spray coating, electroforming, precision casting, lamination, rubber casting, etc.). The combination of RPM technology and ceramic precision casting provides a new way for mold cavity casting. Using RPM/RT technology, from the conceptual design of the mold to the completion of manufacturing, it is only 1/3 of the time required for traditional processing methods and about 1/4 of the cost, and has broad prospects for development. To further improve the competitiveness of RT technology, it is necessary to develop data and processing data to generate a direct and rapid method of manufacturing metal molds that are easier, higher in accuracy, smaller in size, and less in material restrictions.

Ultra-precision machining, micro-fabrication, and composite machining technologies are being developed in the direction of precision and large-sized molds, and super-precision machining, micro-machining, and current-collecting, chemical, ultrasonic, and laser technologies will be developed. At present, ultra-precision machining has reached a submicron level stably, and nano-precision ultra-precision machining technology has also been applied to production. Electromachining, electrochemical machining, beam processing and other processing technologies have become an important part of microfabrication technology. It is more useful for foreign countries to manufacture nanoscale plastic molds with radiation waves with a wavelength of only 0.5 nanometers. Combining laser milling and high-speed milling on a single machine has resulted in new developments in mold processing technology.

Advanced surface treatment technology The mold heat treatment and surface treatment are the keys to the full use of mold material properties. Vacuum heat treatment, cryogenic treatment, vapor deposition (TiN, TiC, etc.) including PVD and CVD technology, ion infiltration, plasma spray and TRD surface treatment technology, diamond-like thin film coating technology, high wear-resistant and high-precision processing technology, non-stick surface Processing and other technologies have been applied in mold manufacturing and have shown good development prospects. The laser heat treatment, welding, strengthening and repairing techniques of the mold surface and other mold surface strengthening and repairing technologies will also receive more attention.

Grinding and Polishing of Mould Grinding Polishing molds are still mainly hand-based, with low efficiency, high labor intensity, and unstable quality. China has introduced a CNC grinding machine that can realize the automatic polishing of three-dimensional surface molds, and the self-researching humanoid intelligent automatic polishing technology has achieved certain results. However, it has few applications at present and is expected to be developed. In the future, we should continue to pay attention to the development of special grinding and polishing technologies such as extrusion honing, laser honing and polishing, electric spark polishing, electrochemical polishing, ultrasonic polishing, and composite polishing technology and process equipment.

The mold making technology includes design and processing. This article analyzes the technical development direction of the Chinese mold industry from these two aspects. The article first pointed out that CAD/CAE, CAPP, and KBE are the main trends in mold design technology; then it discusses the development direction of mold processing technologies, such as high-speed milling, EDM, rapid prototyping, and rapid mode. Finally, the future of the comprehensive technology of mold making was analyzed.

From a technical point of view, mold manufacturing (including design and machining) technology can be broadly divided into five stages of development: manual operation, manual operation plus mechanization (general-purpose machine tools and tools), digital control, computerization, and CAD / CAE/CAM information network technology integration stage.

China has a vast territory, a large number of mold manufacturing companies, and varying levels of technological development. Each phase coexists at the same time. However, at present, it is mainly in the digital control phase. Some key enterprises have developed to a computerized stage. But at the same time, many companies still remain at the stage of manual operation and mechanization. The stage of purely manual operation has basically become history, and the integration stage of CAD/CAE/CAM information network technology has begun to take shape. For most mold manufacturing companies, the future direction of development should be mainly to improve the level of numerical control and computerization, and actively adopt high technology, and gradually move toward CAD/CAE/CAM information network technology integration. The paperless manufacturing of the mold will gradually replace the traditional design and processing.

The development direction of mold design technology Mold design has long depended on human experience and mechanical drawing. Since the development of computer-aided design (CAD) technology for molds in the 1980s, this technology has been recognized and quickly developed. The computer-aided engineering analysis (CAE) technology developed in the 1990s is now also used by many companies. It has a significant effect on shortening the mold manufacturing cycle and improving the mold quality. The CAD technology applied by mold enterprises in some industrialized countries has evolved from two-dimensional design to three-dimensional design, and the three-dimensional design has reached more than 70%. Most companies in China still stay at the level of two-dimensional design, and less than 20% of companies are capable of three-dimensional design. The application of CAE software in foreign countries has become more common, and domestic applications are still relatively small. The level of defects that may occur in the prediction of parts forming process is still relatively low.

Mold design technology and CAD and CAE software should be improved in the following aspects in the future:

* mold design database and knowledge base system;

* mold engineering planning and design;

* Reasonable selection of mold materials and standard parts;

* Mold rigidity, strength, flow path and cooling path design;

Various simulations of plastic mold plastic molding process (injection molding, including plastic mold filling, pressure holding, cooling, warping, shrinkage, fiber orientation, etc., simulation analysis), heat conduction and cooling process analysis, solidification and structural stress analysis. It is very complicated and time-consuming to calculate the distribution of pressure field, temperature field, velocity field, shear strain rate field and shear stress field of casting system and cavity. This simulation technology has evolved from mid-stream technology to two-sided flow technology. It will soon be possible to develop both accurate and fast physical flow technologies and produce three-dimensional injection molding flow simulation software that meets the requirements for the virtual manufacturing of plastic parts.

* Simulation, wrinkling and fracture analysis, stress strain and springback analysis of the metal forming process of the die;

* Casting die-casting forming flow simulation, heat conduction and solidification analysis;

*Forging die forging process simulation and metal flow and filling analysis;

Improve the rapidity, intelligence, and integration of design and analysis software, and enhance their functionality to accommodate the continuous development of molds.

In addition to the mold CAD/CAE technology, the mold process design is also very important. Computer-aided process design (CAPP) technology has begun to be applied in Chinese mold enterprises. As most of the molds are produced in one piece, and their process specifications are different from those of mass production, it is difficult to apply CAPP technology, and it is difficult to have CAPP software suitable for various molds and different mold companies. In order to better use CAPP technology, mold companies must do a good job in development and research. Although CAPP technology is more difficult to apply and promote than CAD and CAE, it must also pay attention to this direction.

Knowledge-based engineering (KBE) technology is an important tool for modern design decision automation. It has become an important way to promote engineering design intelligence. It has received attention in recent years and will have an important impact on the intelligent and optimized design of molds.

The development direction of mold processing technology China's mold is divided into 10 categories 46 sub-categories. Different types of molds have different processing methods, and similar molds can also be completed using different processing techniques. The work of mold processing mainly focuses on mold surface processing, surface processing and assembly. The main processing methods include precision casting, metal cutting, EDM, electrochemical machining, laser and other high-energy beam processing, and two or more processing methods. As one of the composite processing. The continuous development of numerical control and computer technology has made them widely used in many mold processing methods. In the diversification and individuation of industrial product varieties, the product replacement is fast, and the market competition is fierce, the user requires a short delivery time, high precision, good quality, low price, and drives the mold processing technology to the following Several aspects of development.

High-speed milling technology In recent years, some key enterprises in China's mold manufacturing industry have introduced high-speed milling machines and high-speed machining centers, which have played a very good role in mold processing. At present, the maximum speed of the foreign high-speed processing machine tool spindle has exceeded 100000r/min, the rapid feed speed can reach 120m/min, the acceleration can reach 1-2g, and the tool change time can be increased to 1-2s. In this way, the processing efficiency can be greatly improved, and the surface roughness of Ra ≤ 1 can be obtained, and the high hardness material of more than 60HRc can be cut, which poses a challenge to the EDM forming process. With the increase of the spindle speed, the machine tool structure and its configured system and key components, spare parts, and tools must be coordinated to greatly increase the cost of the machine tool. The maximum speed of spindles of high-speed machining tools imported from China will continue to be 10000-20000r/min in the short term, and a few will reach around 40000r/min. Although it is an inevitable direction to develop at higher speeds, the most important thing is to promote it.

High-speed machining is a revolutionary change in the cutting process. From the perspective of technological development, high-speed milling is being combined with ultra-precision machining and hard cutting to open up the field of milling and grinding, and greatly reducing the grinding and polishing of molds. Quantity, shorten the mold manufacturing cycle, the application of mold enterprises in China will come more. Parallel machine tools, also known as virtual axis machine tools, and the birth of 3D laser 6-axis milling machines, and the application of open CNC systems, add more luster to high-speed processing.

EDM Although EDM has been severely challenged by high-speed milling, some inherent characteristics and unique advantages of EDM technology cannot be completely replaced by high-speed milling. For example, the complex profile of a die, and the small and deep cavity , sharp corners, narrow gaps, ravines, deep pits, etc. Although high-speed milling can also meet some of the above processing requirements, the cost is much higher than EDM. EDM is easier to automate than milling. Complex, precision small cavities and micro-cavities and removal of tool marks, complete sharp corners, narrow gaps, trenches, deep pit machining and pattern processing, etc., will be the focus of future EDM applications. In order to further play its unique role in mold processing, the following are the development directions of EDM: