After the steel plate is hot rolled and cold rolled, the thickness of the plate gradually changes from thick to thin. Automobile body, chassis, fuel tank, radiator fins, boiler drum, container shell, motor, electrical iron core silicon steel sheet, etc. are all processed by automobile stamping molds. Metal stamping dies are also used in products such as instruments, household appliances, bicycles, office machinery, and household utensils.

Compared with castings and forgings, metal stamping parts have the characteristics of thinness, uniformity, lightness and strength. Metal stamping can produce workpieces with reinforcing ribs, ribs, undulations or flanges that are difficult to manufacture by other methods to improve their rigidity. Due to the use of precision stamping dies, the accuracy of the workpiece can reach the micron level, and the repeatability is high, and the specifications are consistent. Holes, bosses, etc. can be punched out of metal.

In general, cold-punched metal stamping parts are no longer processed by cutting, or only a small amount of cutting is required. The precision and surface condition of hot stamping metal stamping parts is lower than that of cold stamping metal stamping parts, but it is still better than castings and forgings, and the cutting amount is less.

Hardware stamping is an efficient production method. It uses compound molds, especially multi-station progressive dies, which can complete multiple metal stamping processes on one punching machine, realizing the process from strip uncoiling, leveling, punching to forming , Finished automatic production. High production efficiency, good working conditions, low production cost, generally hundreds of pieces per minute can be produced.

Types of metal stamping process:

Hardware stamping is mainly classified by process, which can be divided into two categories: separation process and forming process. The separation process is also called punching, and its purpose is to separate the metal stamping parts from the sheet along a certain contour line, while ensuring the quality requirements of the separated section. The purpose of the forming process is to make the sheet metal plastically deform without breaking the billet to make a workpiece of the required shape and size. In actual production, multiple processes are often applied to one workpiece. Blanking, bending, shearing, deep drawing, bulging, spinning, and correction are the main metal stamping processes.

The surface and internal properties of sheet metal used in metal stamping have a great influence on the quality of metal stamping products. The thickness of metal stamping materials is required to be accurate and uniform; the surface should be smooth, free of spots, scars, scratches, surface cracks, etc.; The yield strength is uniform without obvious directionality; the uniform elongation is high; the yield ratio is low; and the work hardening is low.

In actual production, process tests similar to the metal stamping process are commonly used, such as deep drawing performance test, bulging performance test, etc. to test the metal stamping performance of the material to ensure the quality of the finished product and a high pass rate.

The precision and structure of stamping dies directly affect the forming and precision of metal stamping parts. Stamping die manufacturing cost and life are important factors that affect the cost and quality of metal stamping parts. The design and manufacture of stamping dies require more time, which prolongs the production preparation time for new metal stamping parts.

The standardization of mold bases, mold bases, and guides and the development of simple stamping molds (for small batch production), composite molds, multi-station progressive molds (for mass production), and the development of rapid mold change devices can reduce hardware Stamping production preparation workload and shortening the preparation time can make it suitable for reducing the preparation workload and shortening the preparation time of metal stamping production, and enable the advanced metal stamping technology suitable for mass production to be reasonably applied to the production of small batches and multiple varieties.

In addition to forming thick plates with hydraulic presses, metal stamping equipment generally uses mechanical punching machines. With modern high-speed multi-station mechanical punching press as the center, it is equipped with uncoiling, leveling, finished product collection, conveying and other machinery, as well as stamping die library and quick die change device. It can be controlled by computer program to form a high-productivity automatic metal stamping production line.

In the case of producing dozens or hundreds of metal stamping parts per minute, the processes of feeding, metal stamping, discharging, and discharging waste are completed in a short period of time, and accidents in personal, equipment and quality often occur. Therefore, safe production in metal stamping is a very important issue.

Seek a breakthrough in the development of the metal stamping and forming industry in case of obstacles:

According to statistics, in 2003, my country produced about 2.4 million tons of stamping parts for automobiles, about 280 million tons/1.9 billion pieces of metal stamping parts for motorcycles, and about 960,000 tons/710 million pieces of metal stamping parts for tractors and agricultural vehicles in 2003. 1 million tons/12.8 billion pieces of hardware stamping parts for household air conditioners and refrigerators. Industry experts predict that as the automotive industry, the largest user market in the metal stamping industry, continues to develop rapidly in the future, China’s metal stamping industry has ushered in a period of rapid development opportunities, but can it seize the opportunity to achieve new and faster development? Experts pointed out that there are still many obstacles and obstacles that need to be overcome and breakthroughs on the way forward.

Resistance 1: Mechanization, low degree of automation

70% of the 680 metal stamping lines in the United States are multi-station presses, and 32% of the 250 production lines in Japan are multi-station presses. The application of this large-scale multi-station press in my country, which represents the current international level However, there are few; small and medium-sized enterprises generally have backward equipment, high energy consumption and serious environmental pollution; simple head forming equipment and heavy manual operation; fine blanking machines are expensive, 5-10 times that of ordinary punches, and most companies are powerless Investment hinders the popularization and application of fine blanking technology in my country; hydroforming, especially internal high pressure forming, requires a large investment in equipment and it is difficult to start domestically.

Breakthrough point: Accelerate technological transformation

To change the current backward situation where most of the materials are loaded and unloaded manually, we should adopt new techniques and improve the degree of mechanization and automation in light of specific conditions. The stamping of automobile body panels should be developed in the direction of single-machine connected automation, robotic hardware stamping production lines, especially large-scale multi-station punching machines. Strive to increase investment and accelerate the technological transformation of the automotive stamping production line, so as to reach the current international level as soon as possible. With the development of microelectronics technology and communication technology, the automation and flexibility of sheet metal forming equipment have a technical foundation. The development of digital flexible forming technology, hydroforming technology, high-precision composite forming technology, as well as profile bending forming technology and related equipment suitable for the new generation of lightweight body structures should be accelerated. At the same time, it will transform the old domestic equipment to make it play a new production capacity.

Resistance 2: Low production concentration

Many automobile groups are large and comprehensive, forming closed internal supporting facilities, leading to various types of metal stamping parts, low production concentration, and small scale. It is easy to cause low-level repetitive construction, and it is difficult to meet the specialized division of labor and market competition. Weak power; the motorcycle metal stamping industry is facing fierce market competition, and is in a state of "superior but not winning, inferior but not eliminating"; the head manufacturing enterprises are small and scattered, with a concentration of only 39.2%.

Breakthrough point: take the road of specialization

Rapidly change the current pattern of “large and complete”, “dispersed and poor”, separate the metal stamping parts from the automobile group as soon as possible, and establish several A large metal stamping parts manufacturing and supply center and dozens of small and specialized parts factories. Only through the road of specialization can the metal stamping parts become bigger and stronger, and become a competitive metal stamping parts supplier in the world.

Resistance 3: Insufficient self-sufficiency rate of metal stamping plates, inconsistent varieties and specifications

At present, my country's automotive sheet can only meet about 60%, while high-end car steel plates, such as high-strength sheets, alloyed galvanized sheets, and ultra-wide sheets (above 1650mm), all rely on imports.

Breakthrough point: materials should be developed in harmony with the industry

The variety of steel plates for automobiles should be more reasonable, and develop towards high-strength, high-corrosion-resistant and thin steel plates of various specifications, and improve the metal stamping performance. Aluminum and magnesium alloys have become rational materials for automobile lightweight, and expansion of their applications is already underway.

Resistance 4: Slow transformation of scientific and technological achievements, slow promotion of advanced technology

In our country, many new metal stamping processing technologies started not too late, and some have reached the international advanced level, but it is often difficult to form productivity. There are not many applications of advanced metal stamping technology, and some are only in the trial stage, and the speed of absorption, transformation, and promotion is slow. The low investment in technology development has resulted in slower grasp and application of advanced technologies by enterprises, and insufficient development and innovation capabilities. The gap between small and medium-sized enterprises in this area is even greater. At present, most domestic enterprises still use traditional metal stamping technology, and lack research and technical reserves for the forming technology needed for the next generation of lightweight automobile structures and materials.

Breakthrough point: Take the road of joint production, learning, and research

Compared with Europe, the United States, and Japan, the biggest gap between China is that there is no industry-university-research consortium, scientific research is difficult to expand, and the results cannot be transformed into productivity as soon as possible. Therefore, it is necessary to focus on large-scale development and industrialization projects, with universities and scientific research units as technical support, and enterprises as application bases, to form a joint entity of products, equipment, materials, and technologies, forming a benign enterprise that can not only develop and innovate, but also rapidly industrialize cycle.

Resistance 5: Large, precision stamping dies rely on imports

At present, the materials, design, and production of metal stamping dies cannot meet the needs of domestic automobile development, and the degree of standardization is still low, about 40% to 45%, while internationally, it is generally about 70%.

Breakthrough: Improving the level of informatization and standardization

Information technology must be used to transform stamping die companies. The focus of development is to vigorously promote the integration of CAD/CAM/CAE technology, especially the computer simulation analysis and optimization technology (CAE) of the forming process. Speed ​​up the standardization process of stamping dies in our country, and improve the accuracy and interchange rate. Strive to reach 60% of the standard parts of stamping die in 2005, and reach more than 70% in 2010 to basically meet market demand.

Resistance Six: Lack of Professionals

High-quality talents with advanced design analysis technology and digital technology in the industry are far from meeting the needs of the rapid development of the metal stamping industry, especially in the motorcycle industry, there is a shortage of and a large number of professional talents with hardware stamping knowledge, technology and skills outflow. In addition, many joint venture companies are designed by foreign parties to control the design rights and investment rights. It is difficult for our metal stamping technicians to truly grasp the true meaning of the metal stamping process.

Breakthrough: Improving the quality of industry personnel

This is an urgent task, but also a long-term and systematic task. The revitalization of my country's hardware stamping industry requires a large number of high-level scientific and technological talents, a large number of entrepreneurs who are familiar with the domestic and foreign markets, and have modern management knowledge and capabilities, and a large number of senior skilled personnel who have mastered advanced technology and craftsmanship. We must be willing to spend great effort to cultivate in a planned and hierarchical manner.