Key issues in developing China’s Automobile Foundry Industry

1. Ensure stable supply

Automobile foundry industry is a mass flow production, which needs mass supply with stable quality. But in fact, up to now, the quality of high-quality foundry coke, high-grade and high-purity cast pig iron and aluminum ingot is still unstable, and the quality of various ferroalloys and treatment agents fluctuates greatly. However, low-grade ferroalloys, such as silver dust iron, mirror iron, silicon mirror iron and blast furnace silicon iron, which are conducive to improving the purity and composition stability of molten iron, reducing costs and improving resource utilization, have not been supplied by manufacturers so far. The quality of bentonite and pulverized coal is also uneven among manufacturers. There are many manufacturers of various binders, additives and sand core coatings for core sand, but few can always meet the quality requirements of users. The small-scale and low-level disorderly competition of China’s foundry raw and auxiliary material production enterprises must be solved, and the degree of specialization, standardization and marketization must be improved; It is necessary to enhance the quality assurance ability, establish perfect technical standards, testing standards and service system, and stable casting raw and auxiliary materials; Implement JIT (just in Ti m e) supply to users, reduce users’ inventory and develop together with users.

2. Improvement of casting mould

The thin wall and precision of automobile castings are inseparable from the precision of dies. At present, there is a big gap between the level of China’s casting mold manufacturing industry and developed countries. For the molds of complex castings such as car cylinder block and cylinder head, the accuracy of domestic manufacturing is difficult to meet the requirements of users. The delivery time is also too long, which is another main aspect restricting the development of China’s automobile casting industry. In order to shorten the manufacturing cycle, mold manufacturers should use CNC machine tools for machining, data EDM, and carry out computer data transmission and exchange with users to convert C a D data into C a m data, so as to realize remote drawing free manufacturing, which can not only shorten the manufacturing cycle, but also ensure accuracy and accuracy and improve efficiency. In particular, some domestic automobile foundry manufacturers are starting to use RP rapid prototyping technology for the trial production of new product castings.

If mold manufacturers can actively cooperate with them, they can choose appropriate rapid mold manufacturing methods, so as to further shorten the mold manufacturing time. At the same time, mold manufacturers must train their own NC processing programmers to make the molds ordered according to the drawings also adopt NC processing. As for some special occasions, there is neither C a D data nor low figure. There is only the real object. When we want to order the mold, as long as our mold manufacturer improves the technical level and ability, we can also use the reverse engineering method to digitally measure (scan) the real object, so as to complete the data acquisition and programming required for mold NC machining, The casting mould can be processed numerically.

3. Improve the level of caster

The equipment used in automobile foundry industry must be fast beat, high efficiency and high reliability equipment suitable for continuous work. Due to the high quality requirements of car castings, these casting equipment must be of high precision. Equipment for automobile foundry industry. For China’s casting machine industry, it is undoubtedly a highly profitable market, but most casting equipment manufacturers have weak technical strength, lack of technical development ability, and fight their own battles. They do not form the advantage of the combination of production, learning and research. They are weak, so they have to look at many foreign casting equipment manufacturers, It has snatched a large number of equipment orders from China’s automobile foundry industry. The young Automobile Casting Industry in China, despite the shortage of funds, had to spend high prices to import some key equipment, otherwise it could not produce the automobile castings needed for cars. This dilemma must be reversed. Appropriate measures can be taken, such as Sino foreign joint venture or cooperation, or the combination of domestic industry, University and research, joint development with users, and the import of key components (such as servo mechanism, hydraulic components, electronic and electric control components, etc.). These are the ways to accelerate the improvement of the level of China’s casting machine industry, and also solve the demand of China’s automobile casting industry for high-level, high reliability and reasonable price casting equipment.

4. Strengthen quality management

Although China’s Automobile Foundry manufacturers have passed the 1509000 quality demonstration one after another, they also attach importance to six factors affecting quality in daily management: people (employees), machines (equipment, molds), materials (raw and auxiliary materials), methods (process and operation), rings (operating environment, process) and testing (detection and inspection), However, the effective and stable operation of the 150900 quality assurance system has not been grasped, and the above six influencing factors have not been always brought into the NC State. As for the ability to consider quality assurance at the same time from the development, design and process formulation of new products, so as to eliminate possible casting defects to the greatest extent, it is even less before putting into production.

We should review the casting quality from the perspective of users, so as to make users satisfied (not just the satisfaction of the enterprise) and really operate according to the 1509000 quality assurance system, which is the pass to enter the international market. If our castings are to be supplied to Volkswagen AG, they should also pass the VDA 6.1 certification required by the company. If we want to supply to a major automobile company in the United States, they should pass the Q S G 0 certification required by them. In the quality assurance system of German and American automobile companies, the quality control of raw materials into the factory is regarded as the key link and the premise of stable casting quality.

Our quality control in the production process should not be limited to sampling inspection or single process control. We should strengthen on-line real-time control and implement closed-loop control for conditional process. For example, the cupola shall be controlled through the three-dimensional network curve of air volume and coke consumption according to the preset molten iron temperature and melting rate. This is a necessary measure to reduce the fluctuation of C, SL and other components. Otherwise, the cupola will actually become an “uncontrollable cupola”. Even if the raw materials are ideal, the fluctuation of C, Si and other components cannot be controlled within the minimum range. Advanced quality detection and control instruments, such as X-ray fluorescence spectrometer for quality inspection of raw and auxiliary materials, image analyzer of casting alloy, computer expert system, neural network and fuzzy control, should be applied to quality detection and control of cupola smelting process and molding sand preparation process. The quality control of finished castings is not only to reduce the scrap rate, but also to improve the internal quality control (i.e. material performance), surface quality, inner cavity cleanliness and dimensional accuracy, which are most concerned by users. Digital information storage shall be adopted for various data, parameters, photos, images and tables of quality management, which not only greatly saves photos and paper, but also is conducive to information analysis and sharing. Try to reduce the inventory of raw and auxiliary materials, sand core inventory and casting inventory, which can not only reduce the capital occupation and speed up the capital turnover, but also facilitate the quality tracking management, contribute to the analysis and judgment of the causes of quality problems, and is of great significance to improve the quality level and reduce the cost.

5. Accelerating integrated development

The automobile foundry industry should change the traditional serial and sequential working mode with the working method of concurrent engineering, and work with the automobile product development department to intervene from the product R & D stage and integrate the requirements of casting process into the overall concept of product design. At the same time, within the foundry enterprise, it also enables the personnel of various categories to brainstorm and form a team work mode to improve work efficiency. In the five aspects of Ca, the foundry industry has introduced magma and P R O.C a st software. Chinese foundry workers have also developed some casting software, which can use the two-dimensional and three-dimensional data of the product, use the above casting process simulation software and solidification process simulation to simulate the metallographic structure, component segregation and material properties, and carry out the velocity field Simulation of concentration field, temperature field, phase field, stress field and strain field. This will enable us to optimize the process scheme by means of C a e before formally determining the casting process.

On the basis of CAE optimization, we can use advanced RP rapid forming technology to trial produce new product castings. That is, using the one-dimensional data of CAD / CAE as the control data of computer three-dimensional modeling, the materials are stacked layer by layer to form the prototype of the casting or the prototype of the pattern required by the casting through bonding, fusion or sintering. The former can be used to turn out the casting sample by means of wax loss casting, and the latter can be directly used as a mold for core assembly molding with self hardening sand to pour out the casting. Powder laser sintering method can also be used to sinter sand mold and directly pour castings. The CAD / CAE three-dimensional data can also be input into the NC machine tool, and the machinable plastic can be used for cam processing, so as to obtain the core box and pattern required for the trial production of castings, which can be used for the trial production of small batch castings. In a word, the combination of C a D / C a V and R P makes the process scheme optimization and casting trial production break through the lengthy, inaccurate and unsatisfactory mode of traditional two-dimensional drawing and wood mold trial production, and greatly shorten the development cycle, especially the development time of complex castings such as cylinder block, cylinder head, gearbox shell, inlet and exhaust manifold, It is of great significance to shorten the development cycle of the whole engine and vehicle and put it on the market as soon as possible.