With the development of human society and the progress of culture, art, production tools and technology, the economy is also developing constantly. In the long history of thousands of years, China is far ahead of other countries with its excellent civilization, especially its economic strength. From the Millennium History of Century Economy written by Angus Madison, an Englishman, we can see that the proportion of China's total economic output to the world's total economic output was 22.7% in 1000, 25% in 1500 and 29.2% in 1600. Eastern civilization is ahead of the western world.
However, this pattern changed fundamentally after17th century. With the establishment of British capitalist system, steam engines began to be used in the field of production, and machine production replaced manual production. The world entered age of steam from the "handicraft era" and the first industrial revolution began, which greatly promoted the economic development of European countries. Due to the change of production mode, the production capacity has been greatly improved, and the domestic market can't digest the growing commodity production in time, so capitalist countries such as Britain, France, Germany, Italy and the Netherlands have expanded their colonies to other continents such as Asia and Africa to find new markets and raw material supply places. Obviously, the European civilization represented by Britain, France, Germany, Italy and the Netherlands has caught up with and surpassed Asia, thus forming the situation that the East is subordinate to the West, which can be said to have created and changed the world pattern. The most substantial change is from the second industrial revolution to the middle of the 20th century. After 1870, due to the wide application of electric power, the world has moved from "age of steam" to "electrical age", and the development of science and technology has advanced by leaps and bounds, and various new technologies and inventions have emerged one after another, which have been quickly applied to industrial production, greatly promoting the development of the world economy. In particular, the rise of the United States shows that manufacturing plays an important role in a country. /kloc-at the end of 0/8, the United States followed the example of Britain and embarked on the road of industrialization and modernization after independence. Since the Elizabethan era, Britain's manufacturing industry has been encouraged by the state, and its commercial power has begun to expand globally. During the reign of Louis XIV, France made great progress in industry and commerce. Spain and Portugal have seized a large number of commercial strongholds all over the world, and even countries such as Russia and Turkey are developing commerce and manufacturing. This is the general trend. Therefore, the United States realizes that only by devoting itself to the development of industry and commerce, especially the development of manufacturing and the use of machinery, can the United States rank among the world powers. Based on this concept, the United States vigorously develops manufacturing industry. /kloc-In the first half of the 9th century, the most important development in America was the establishment of the new factory system. It combines the original scattered production processes and implements a new division of labor, and then concentrates all the processes of manufacturing a certain commodity in one factory and puts them under unified management. After more than one hundred years of development, by the end of 19, the world financial center had moved from London to new york, and the United States became the most developed country and the largest economic power in the world. It can be said that the manufacturing industry has not only changed the world pattern, but also determined the development level of a country. For example, 68% of the wealth in the United States comes from manufacturing, and 49% of the gross national product is provided by manufacturing. Since the reform and opening up, China's manufacturing industry has developed rapidly. 20 1 1 year, the annual output value of China's high-tech manufacturing industry reached 9.2 trillion yuan, accounting for 19.5 1% of China's GDP, and the total export value of processing trade reached 835.4 billion US dollars, accounting for11. The development of manufacturing industry not only provides a guarantee for ordinary people's daily life, but also lays a foundation for improving China's comprehensive national strength.
Since the global economic crisis triggered by American finance broke out in 2008, the world economy seems to have never been out of the trough. Although many attempts were made to rebound during the period, the growth was still weak due to lack of stamina. Historical experience has repeatedly proved that when the global economy is in recession, it is the time when the new economy sprouts and new technologies are born. The global economic depression shows that the traditional relations of production have seriously hindered the development of productive forces, and change will become a new driving force for relations of production.
Since the beginning of this year, the discussion on the third industrial revolution has reached a climax. American scholar Jeremy Rifkin said that the combination of Internet and new energy will trigger a new round of industrial revolution-this will be the third "revolution" after the steam engine of19th century and the electrification of 20th century. The British "Economist" magazine also pointed out that the market potential of 3D printing technology is huge, and it is bound to become one of many breakthroughs leading the future manufacturing trend. These breakthroughs will make the factory completely bid farewell to traditional tools such as lathes, drills, punches and molding machines, and be dominated by more dexterous computer software, which is the symbol of the arrival of the third industrial revolution.
3D printing technology is a non-traditional processing technology, also known as additive manufacturing and rapid prototyping. It is an advanced manufacturing technology integrating optics, machinery, electricity, computer, numerical control and new materials, which has attracted the interest of the global advanced manufacturing field in recent 30 years. Different from the "removal method" of materials such as cutting, this technology "naturally grows" into a three-dimensional solid by stacking discrete materials such as powder and liquid flakes layer by layer, and turns the three-dimensional solid into several two-dimensional planes, which greatly reduces the manufacturing complexity. Theoretically, as long as the structural model is designed on the computer, this technology can be applied to quickly turn the design into a physical object without tools, molds and complicated technological conditions. This technology is especially suitable for the rapid manufacturing of parts with small batch, asymmetric structure, multi-curved surface and multi-content structure (such as aero-engine hollow blades, human skeleton repair, conformal cooling channels) in aerospace, weapons and equipment, biomedicine, molds and other fields. , in line with modern and future development trends.
The Origin and Development of 3D Printing Technology
The core manufacturing concept of 3D printing technology originated in America. As early as in 1892, J.E.Blanther suggested in his patent that the topographic map should be constructed by layered manufacturing method. 1902, Carlo Baese put forward the principle of making plastic parts with photopolymer. 1904, Pereira put forward the method of cutting the outline on cardboard and then gluing these cardboard into a three-dimensional topographic map. After 1950s, hundreds of patents about 3D printing appeared. In the late 1980s, 3D manufacturing technology had a fundamental development, and more patents appeared. Only 24 American patents are registered between 1986- 1998. 1986 Mr. Hull invented the stereolithography appearance (SLA), 1988 invented the layered solid manufacturing, 1988 Dyke invented the powder laser sintering technology (SLS), 1992 Krupp invented FDM, fused deposition molding (FDM).
With the continuous invention of patented 3D printing technology, the corresponding production equipment has also developed. From 65438 to 0988, American 3D Systems Company produced the first modern 3D printing equipment-SLA-250 (light curing molding machine) according to Hull's patent, which initiated a new era of 3D printing technology development. In the following 10 years, 3D printing technology flourished, and more than ten new technologies and corresponding 3D printing equipment appeared. FDM equipment of Stratasys, SGC equipment of Cubital and LOM equipment of Helisys were commercialized in 199 1. 1992 DTM (now a 3D system) successfully developed SLS technology. 1994 EOSINT selective laser sintering equipment was introduced by EOS company in Germany. 1996 3D Systems manufactured its first 3D printer, actua2100, using inkjet printing technology. In the same year, Z Company also released Z402 3D printer. Generally speaking, the United States occupies a leading position in equipment research and development, production and sales, and its development level and trend basically represent the development level and trend of the world. Europe and Japan are not far behind, and have carried out relevant technical research and equipment research and development. At that time, although Taiwan Province Provincial University had LOM equipment, 4SL series equipment was imported and installed by various units and armies in Taiwan Province Province, and the Hong Kong Productivity Council, Hong Kong University of Science and Technology, Hong Kong Polytechnic University and City University of Hong Kong all had RP equipment, with emphasis on the application and promotion of related technologies.
Comrade Deng Xiaoping said that science and technology are the primary productive forces. As the most advanced manufacturing method, 3D printing technology also represents the most advanced science and technology in the world. The party and the country have always attached importance to the development of science and technology industry. In the mid-1980s, the CPC Central Committee and the State Council put forward and implemented a high-tech research and development plan, and set up 15 special projects in many fields that have a great impact on China's future economic and social development, such as biotechnology, information technology, automation technology, new material technology and laser technology, so as to track the world's advanced level. In this situation, 1994 established the first Beijing Long Yuan Automobile Molding Co., Ltd. engaged in 3D printing in China, with a registered capital of US$ 2 million, specializing in R&D and sales of rapid prototyping equipment, and successfully manufactured the first SLS rapid prototyping equipment in China-AFS-360 that year. This equipment uses polypropylene (PP) and plastic powder (PS) as raw materials to produce dentures, golf club heads and skulls.
3D printing technology and equipment level
In terms of equipment research and development, Germany, the United States and Japan are at the world's leading level in this field, and a number of well-known enterprises specializing in large-scale production of 3D printing equipment have been formed, such as EOS in Germany, 3D Systems in the United States and CMET in Japan. SLA equipment produced by 3D Systems accounts for the largest proportion in the international market. Since 1988, enterprises have successively introduced SLA equipment such as SLA-250, 250HR, 3500, 5000, 7000 and Viper Pro system (the maximum molding space reaches 1500×750×550mm). Its main technical advantages are long service life (more than 5000 hours) and high molding accuracy (more than 5000 hours). Denken Engineering Company and Autostrade Company of Japan broke the convention of using ultraviolet light source for SLA equipment and took the lead in using semiconductor laser with wavelength of about 680nm as light source, which greatly reduced the cost of SLA equipment. In terms of SLS equipment, German EOS Company and American 3D Systems Company are the main providers of this technology in the world. Molding materials have expanded from early polymer materials to functional materials such as metals and ceramics. The forming accuracy is about 0. 1-0.2mm, and the forming space is gradually increasing, with the maximum mesa exceeding 500 mm In the field of metal direct 3D printing, there are many mature equipment manufacturers all over the world, including EOS (EOSING M270) in Germany, MCP (Realizer series) in the United States and Concept laser (M Cusing series) in Germany. EBM equipment of Acram Company in Sweden also occupies an important position.
Since the first laser rapid prototyping machine was successfully developed in 1994, Beijing Long Yuan company has been committed to the development of the rapid prototyping machine for selective laser powder sintering (SLS), and to the application and processing services of rapid prototyping. SLS equipment such as AFS-360,500, lasercore 5100,5300,7000, etc. (Maximum molding space 1400×700×400mm) has been introduced one after another, and now there are users with more than 1 10. As the general manager of the company, Feng Tao graduated from Tsinghua University and worked in Tsinghua University Institute of Polymer Materials. He has good theoretical knowledge and practical experience in polymer materials and laser optics, and is one of the earliest experts engaged in laser rapid prototyping technology research in China. He has profound attainments in the application and materials of 3D printing technology. As early as 1995, he proposed to apply SLS to rapid precision manufacturing. Compared with other 3D printer technologies, the most prominent advantage of SLS is that the molding materials are widely used. Theoretically, any powder material that can form bonds between atoms after heating can be used as the molding material of SLS. At present, the materials that SLS can successfully process are paraffin, polymer, metal, ceramic powder and their composite powder materials. SLS is more and more widely used because of its wide variety of molding materials, material saving, wide distribution of molded parts' properties, and suitability for various purposes, and SLS does not need to design and manufacture complex support systems. Under his leadership, Long Yuan Company successfully developed complex manufacturing methods such as investment casting, wax casting and shell casting, and later developed the application method of polystyrene powder and materials in 3D printing. Now Feng Tao has begun to study the application of metal powder in SLS technology, and achieved certain results. In his view, it is of great significance to realize the direct sintering of high-melting metal parts, which are high-strength parts that are difficult to manufacture by traditional cutting methods, and 3D printing technology is more widely used. The research direction of SLS forming technology in the field of metal materials should be the sintering of unit metal parts, multi-alloy parts, laser sintering of advanced metal materials such as metal nano-materials and amorphous metal alloys. It is especially suitable for the molding of micro parts made of cemented carbide materials. In addition, according to the specific function and economic requirements of the parts, the parts with functional gradient and structural gradient are sintered. With the mastery of the forming mechanism of laser sintering metal powder, the acquisition of the best sintering parameters of various metal materials and the emergence of special rapid prototyping materials, the research and introduction of SLS technology will surely enter a new realm.
Wide application
As an advanced manufacturing technology integrating optics, machinery, electricity, computer, numerical control and new materials, 3D printing technology has been widely used in aerospace, military and weapons, automobiles and racing cars, electronics, biomedicine, dentistry, jewelry, games, consumer goods and daily necessities, food, architecture, education and many other fields. It can be predicted that 3D printing technology will tend to the direction of daily consumer goods manufacturing, functional parts manufacturing and organizational structure integration manufacturing.
Aerospace: Aerospace products are characterized by complex shapes, small batches, large differences in parts specifications and high reliability requirements. The shaping of products is a complex and precise process, which often requires many times of design, testing and improvement. It is expensive and time-consuming, and it is difficult to manufacture by traditional methods. 3D printing technology has a unique application prospect in the research and development of modern aerospace products because of its flexible and diverse process methods and technical advantages. Abroad, the application of 3D printing technology in the aerospace field has a long history. Boeing Company of the United States combines 3D printing technology with traditional casting technology to manufacture cargo door brackets made of different materials such as aluminum alloy, titanium alloy and stainless steel. General motors uses 3D printing technology to manufacture key components such as aerospace and ship impellers; Mammoth laser rapid prototyping system of Belgium Materialise company, the maximum processing size can reach 2200mm; In China, Beijing Long Yuan relies on its own technological advantages, and the China Aerospace Department and other departments and aircraft manufacturing companies provide production services for helicopter engines, helicopter cases, worm gear pumps, titanium racks, exhaust pipes (with a maximum height of 2800mm), aircraft suspensions, flywheel shells and other aircraft parts.
Military industry: Compared with traditional manufacturing technology, 3D printing technology has the characteristics of simplification and operability, especially for the processing of some new materials, the effect is particularly remarkable. For example, aluminum alloy has always been the most widely used metal structural material in military industry. Aluminum alloy has the characteristics of low density, high strength, good corrosion resistance and high temperature resistance. As a structural material, due to its excellent processability, it can be made into profiles, pipes, high-ribbed plates, etc. with various sections, so as to give full play to the potential of materials and improve the rigidity and strength of components. Therefore, aluminum alloy is the first choice for lightweight structural materials of weapons. The U.S. military applied 3D printing technology to assist in manufacturing the model of pop-up igniter for missiles, and achieved good results. In China, titanium alloy has been widely used in the manufacture of self-propelled gun turrets, components, armored vehicles, tanks and military helicopters. From 65438 to 0999, Beijing Long Yuan Automobile Forming Co., Ltd. participated in the development of several national key projects by using 3D printing technology, such as: large thrust rocket liquid oxygen-kerosene, liquid oxygen-liquid hydrogen engine; JS-Ⅱ new tank turbocharger and satellite gyroscope frame: the shell of the observation mirror of infrared guidance instrument, which further promoted the development of China's military industry.
Automobile manufacturing: At present, Audi of Germany uses KUKA robot with successful 3D printing technology to manufacture Audi RSQ cars. With the development of China's automobile industry and the rapid increase of automobile output, some key parts are becoming more and more complex, large-scale and lightweight, which requires the integration and integrated manufacturing of parts. The traditional process of changing sand into molds with molds is becoming more and more complicated, and the number of live parts is also increasing sharply, which restricts the development of China's automobile industry. Therefore, Feng Tao, general manager of Beijing Long Yuan Company, began to study 3D printing technology to produce automobile engines. SLS is a plastic material that uses the heat provided by infrared laser beam to form three-dimensional parts. At the beginning of processing, a thin layer of thermoplastic powder (100μ m ~ 250μ m) is evenly spread on the working platform and heated to a temperature below the melting point by an auxiliary heating device. On the uniform powder surface, the computer controls the laser to scan according to the information of the current layer of the part, and the powder is sintered at the place scanned by the laser to form a solid. The powder has not been scanned yet, so it can be used as the support of the next layer and can be taken out after molding. After the upper layer is made, the forming piston descends by one layer and the powder feeding piston rises. The powder is moved from the powder supply piston to the forming piston by the powder spreading roller, and the powder can be leveled to scan the next layer. Repeat this auxiliary powder and selective sintering process until the last layer, thus making a three-dimensional solid. One of the biggest characteristics of SLS is that the molding process has nothing to do with the complexity, so it is especially suitable for engine blocks, cylinder heads, intake and exhaust pipes and other parts with extremely complicated internal structures. Another important feature is a wide range of molding materials, especially resin sand and disappearing investment. Therefore, combined with casting technology, engine parts can be cast quickly. SLS technology effectively combines rapid prototyping technology with traditional casting technology to rapidly manufacture complex metal parts. Engine cylinder block and cylinder head are generally cast products. Using rapid casting technology, engine products with the same material and similar performance as the final products can be obtained in a short time for testing and inspection. Feng Tao believes that rapid casting technology is the product of the combination of SLS technology and casting technology, which is characterized by simplicity, accuracy, reliability and good ductility, and can be effectively applied to rapid prototype manufacturing in the engine design and development stage. It is suitable for trial production and production of single piece and small batch, can respond to the market quickly, provide small batch products for testing and inspection, and help to ensure the speed of product development. The controllability of the molding process can be modified at a low cost in the design and development stages in order to check the design or provide an assembly model. It is helpful to improve the quality of product development. The diversity of raw materials for rapid prototyping provides different process combinations for the product development stage. Because the localization and molding process of SLS raw materials can be organically combined with traditional processes, it is helpful to reduce the development cost. The rapidity of the combination process supports the improvement of product update frequency and helps to promote products to enter the market as soon as possible. Using 3D printing technology to produce engine cylinder block, cylinder head, gearbox housing, etc. For automobile manufacturers, not only the manufacturing speed is high, but also the precision is high, thus making the manufacturing of complex automobile parts digital, precise, flexible and green. At present, many domestic engines of high-speed rail, bullet trains and subways are made in Long Yuan.
Biomedicine: At present, 3D printing technology is also applied to biomedicine, including bones, teeth, artificial liver, artificial blood vessels, and drug manufacturing. In terms of biological manufacturing, developed countries such as Europe and the United States have carried out a lot of research and extensive clinical applications: in the United States, medical hearing AIDS, eye lens models, dentures and so on can be manufactured by SLA manufacturing technology and biocompatible resins; In Italy, human skeleton prosthesis is manufactured by SLA manufacturing technology. 1998 Beijing Long Yuan Company cooperated with Peking University Stomatological Hospital. Stomatological hospital transmits the CT scanning data of patients from CT workstation to PC after being processed by Magics software, and records and stores them in standard format (Dicom format) and provides them to Beijing Long Yuan Company. Beijing Long Yuan Company developed AFS-320 rapid prototyping machine, using selective laser powder sintering method. The raw material is polystyrene powder, which is made into a solid model to treat fibrous dysplasia of cheekbones and maxilla, and good results have been achieved. At the same time, it is used to treat the old comminuted fracture of zygomatic arch, and the clinical application results show that the treatment effect is good.
Important strategic significance
3D printing technology has a wide range.