With the development of human civilization, the progress of culture, art, production tools and technology, the social economy continues to develop. 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 demand for 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. European civilization, represented by Britain, France, Germany, Italy and the Netherlands, has surpassed Asia, thus forming a situation in which the East is subordinate to the West, which can be said to have created and changed the world pattern. The most substantial change took place between the second industrial revolution and 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. Especially the rise of the United States, shows that manufacturing plays an important role in the development of a country. /kloc-at the end of 0/8, the United States began to follow the example of Britain and take the road of industrialization and modernization after independence. The United States realized that only by devoting itself to the development of manufacturing industry can it rank among the world powers. /kloc-In the first half of the 9th century, the most important development in America was the establishment of the new factory system. For example, it combines the original scattered production processes, implements a new division of labor, and then concentrates all the processes of manufacturing a certain commodity in one factory for unified management. After 100 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. It can be seen that the development of manufacturing industry not only provides a guarantee for the daily life of ordinary people, 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-it 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 in the global advanced manufacturing field in recent 30 years. Different from the traditional "removal method" of materials such as cutting, 3D printing technology "naturally grows" into three-dimensional entities by stacking discrete materials such as powder and liquid sheets layer by layer. This technology turns a three-dimensional solid into several two-dimensional planes, which greatly reduces the manufacturing complexity. In theory, 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 processes. This technology is especially suitable for the rapid manufacturing of small batch, asymmetric structure, multi-curved surface and internal structural parts (such as aero-engine hollow blades, human skeleton restorations, conformal cooling channels, etc.). ) in aerospace, weapons and equipment, biomedicine, automobile manufacturing, 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 printing technology had a fundamental development, and more patents appeared. Only 24 American patents are registered between 1986- 1998. Hull invented stereolithography appearance (SLA) in 1986, layered solid manufacturing in 1988 by Fagin, and powder laser sintering (SLS) in 1989 by Deckard. 1992, Crump invented the fused deposition molding technology (FDM), 1993, Sachs invented the 3D printing technology at MIT.
With the continuous invention of various patented 3D printing technologies, its corresponding production equipment has been developed one after another. 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 ten years, 3D printing technology flourished, and more than ten new processes and corresponding 3D printing equipment appeared. 199 1 year, Stratasys FDM equipment, Cubital SGC, Solid Ground Curing (SGC) equipment and Helisys LOM equipment were commercialized. 1992, DTM SLS technology (now a 3D system) was successfully developed. 1994, EOS company of Germany introduced EOSINT selective laser sintering equipment; 1996, 3D Systems company manufactured its first 3D printer-actua2100 by using inkjet printing technology; In the same year, Z Corp also released the 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, all units and armies in Taiwan Province Province imported and installed SL series equipment. 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, focusing on the application and promotion of related technologies.
As the most advanced manufacturing method, 3D printing technology also represents the most advanced science and technology in the world. Deng Xiaoping said that science and technology are the primary productive forces. 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 earliest professional 3D printing company in China-Beijing Long Yuan Automobile Molding Co., Ltd., with a registered capital of 2 million US dollars, specializing in the research and development and sales of rapid prototyping equipment, and successfully manufactured the first SLS rapid prototyping equipment in China-AFS-360.
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. Among them, SLA equipment produced by 3D Systems accounts for the largest proportion in the international market. Starting from 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. 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 molding accuracy is about 0. 1-0.2mm, and the molding 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) and Concept laser (M Cusing series) in Germany, MCP (Realizer series) in the United States and Acram (EBM equipment) in Sweden.
China began to develop 3D printing in the early 1990s. Since the first laser rapid prototyping machine was successfully developed by 1994, Beijing Long Yuan Company has devoted itself to the development of SLS rapid prototyping machine, as well as the application and processing services of rapid prototyping. SLS equipment of AFS-360,500, lasercore-5100,5300,7000 and other models (the maximum molding space is 1400×700×400mm) has been introduced successively, and now it has11.
As the general manager and chief engineer of the company, Feng Tao graduated from Tsinghua University and worked in Tsinghua University Institute of Polymer Materials. He has rich theoretical 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 molding materials are various, saving materials, and the properties of molded parts are widely distributed. In addition, SLS does not need to design and manufacture complex support systems, so it is suitable for many purposes. Under his leadership, Beijing Long Yuan has successfully developed complex manufacturing methods such as investment casting, wax molding, casting shell, and the application methods of polystyrene powder and synthetic 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, the direct sintering of high-melting metal parts is of great significance for the wider application of 3D printing technology in high-strength parts that are difficult to manufacture by traditional cutting methods. Feng Tao believes that the research direction of SLS forming technology in the field of metal materials should be the sintering of single system metal parts, multi-alloy materials and laser sintering of advanced metal materials such as metal nano-materials and amorphous metal alloys. This is especially suitable for the forming 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. It can be predicted that 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.
As the earliest company in China to realize the industrialization and service of 3D printing technology, Beijing Long Yuan can be regarded as the leader of 3D printing technology in China from its numerous achievements in the application of 3D printing equipment and materials and its role in promoting the development of 3D printing industry in China.
1994 successfully manufactured the first SLS rapid prototyping equipment in China, specializing in the research and development and sales of rapid prototyping equipment; 1995 passed the expert appraisal organized by Beijing Municipal Science and Technology Commission; During the period of 1997, the research on sintered materials and rapid casting technology for precision casting was successful and entered the field of rapid development of complex metal structures. 1998 participated in the rapid prototyping demonstration service center project of the Ministry of Science and Technology, and the equipment was selected by two service centers; In 2000, the rapid casting process of metal parts with complex internal cavity structure was successfully developed based on SLS, which laid the foundation for the rapid manufacturing of engine parts with complex structure, and the direct molding technology of metal materials entered a substantive development stage; In 2002, he began to cooperate with China Academy of Engineering Physics to study the direct manufacturing of metal parts by high-power laser. In 2004, we cooperated with South China University of Technology to develop selective laser melting metal forming technology. At present, stainless steel and nickel-base alloy steel parts with density of 100% can be manufactured. In 2003, AFS-450, a large-scale rapid prototyping equipment, was introduced. Compared with AFS-320, there were 22 major improvements in software and hardware. The equipment is more stable, reliable, humanized, fast and accurate, and becomes the first choice for enterprise users; AFS-500 was introduced in 2005, and the molding size was 125 liter, which was sold that year. The sintered investment casting wax that can be directly removed by steam was introduced, which was seamlessly connected with the traditional precision casting, thus solving the problem of rough surface of titanium alloy rapid casting. In 2008, AFS-700 molding equipment was developed, and the molding size reached 245 liters. It was the largest laser powder sintering equipment at that time and met the requirements of most precision castings. The equipment adopts a brand-new feeding and powder laying method, which reduces the time of one-way powder laying by half and does not need intermediate feeding. The equipment was sold that year; In 2009, laser sintering sand achieved a breakthrough. The strength and gas production of sand core meet the casting requirements. The laser core-making machine, a special equipment for sintering molding of casting coated sand, was developed. In 20 10, the prototype of laser core -5300 was developed and put into trial sale.
Wide application fields of 3D printing technology
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 this technology will tend to the direction of daily consumer goods manufacturing, functional parts manufacturing and organizational structure integration manufacturing. Below, we can see the wide application of 3D printing technology from several main fields.
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 difficult to manufacture by traditional methods. Therefore, 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 this field has a long history. For example, 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; The mammoth laser rapid prototyping system of Belgium Materialise Company has a maximum processing size of 2200mm at a time. At home, Beijing Long Yuan, relying on its own technical advantages, provides production and services of helicopter engine, helicopter casing, worm gear pump, titanium frame, exhaust duct (with a maximum height of 2800mm), aircraft suspension, flywheel housing and other aircraft parts for China aerospace departments and aircraft manufacturing enterprises: 1996. The first commercial SLS rapid prototype was sold to Beijing Aviation Materials Institute and successfully applied to new military aviation products. 1999, the second generation commercial equipment AFS-320 was successfully put on the market. The application of rapid prototyping has been gradually developed, and it has participated in the development of key aerospace projects in many countries, such as liquid oxygen-kerosene, liquid oxygen-liquid hydrogen engine and satellite gyroscope frame for large thrust rockets.
Military industry: Compared with traditional manufacturing technology, 3D printing technology is simple and easy to operate, especially suitable for processing some new materials. 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., so as to give full play to the potential of materials and improve the stiffness 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, military helicopters and so on. From 65438 to 0999, Beijing Long Yuan Automobile Forming Co., Ltd. used 3D printing technology to participate in the development and research of several national key military projects, such as the turbocharger of JS-II new tank and the observation mirror shell of infrared guidance instrument. In 2002, we started the research on direct manufacturing of metal parts by high-power laser with China Academy of Engineering Physics, which further promoted the development of China's military industry.
Automobile manufacturing: There have been many successful cases of 3D printing technology in automobile manufacturing abroad. For example, Audi of Germany successfully manufactured an Audi RSQ car equipped with a KUKA robot by using 3D printing technology. With the development of China's automobile industry, the automobile output is increasing rapidly, and some key parts are becoming more and more complex, large-scale and lightweight, which requires the integration and integrated manufacturing of parts. However, the traditional molding process of sand casting makes the mold more and more complicated, and the number of parts increases sharply, which restricts the development of China's automobile industry to some extent. Therefore, the technical team of Beijing Long Yuan, which leads the domestic 3D printing technology, started the research of 3D printing technology in the field of automobile engine manufacturing. SLS is a kind of hot-melt plastic which uses the heat provided by infrared laser beam to form three-dimensional parts. One of its biggest characteristics is that the forming process has nothing to do with the complexity, so it is especially suitable for engine cylinder block, cylinder head, intake and exhaust pipes and other parts with extremely complicated internal structures. In addition, SLS technology has a wide range of molding materials, especially casting resin sand and consumable investment materials, so it can be combined with casting technology to rapidly cast engine parts. The combination of SLS technology and casting technology produces rapid casting technology, which can be effectively applied to prototype rapid manufacturing in 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, Long Yuan's products can be seen on the engines of many high-speed trains, bullet trains and subways in China. The following are Long Yuan's R&D achievements in the application of automobile engines: 200 1, which has successfully studied the rapid prototyping and rapid manufacturing technology of automobile key structural parts, and provided RP services for automobile enterprises for cylinder block, cylinder head, intake pipe and gearbox shell; In 2006, the technology of laser direct molding casting sand core was introduced to the market, and the first molding equipment specially used for casting sand core was sold. And successfully applied to the rapid development of automobile engine cylinder block, cylinder head and supercharger; 20 1 1 year, in order to meet the needs of diesel engines and other industries, a large-size laser core-making machine was developed; Through cooperation with Guangxi Yuchai Machinery Co., Ltd. and Dongfeng Commercial Vehicle Technology Research Institute, the rapid manufacturing method and technology of diesel engine cylinder head are developed.
Biomedicine: At present, 3D printing technology has also been applied to the biomedical field, including bones, teeth, artificial liver, artificial blood vessels, pharmaceutical manufacturing and so on. 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. In China, Beijing Long Yuan cooperates with Peking University Stomatological Hospital. The CT scanning data of patients are processed by the CT workstation through Magics software, then transmitted to PC, burned and stored in standard format (Dicom format), and then provided to Long Yuan. Based on this, Long Yuan developed AFS-320 rapid prototyping machine. The equipment adopts selective laser powder sintering method, and the raw material is polystyrene powder, and a solid model is made. It can be used for symptoms such as abnormal hyperplasia of bone fibers in cheekbones and maxilla in stomatology, and has achieved good curative effect. At the same time, the clinical application results show that the treatment effect is good in the treatment of old comminuted fractures of zygomatic bone and zygomatic arch. At present, Long Yuan has reached a new round of cooperation intention with Peking University Stomatological Hospital, that is, the professional rapid prototyping and rapid manufacturing scheme in the field of stomatology: using specific CAD software, the CAD design of denture can be realized, including the 3D design of abutment, crown, bridge, crown, veneer and inlay. With the help of CAD design, rapid prototyping and rapid manufacturing of dentures can realize automatic production with high efficiency, less consumables and low cost.
The Prospect and Strategic Significance of 3D Printing Technology
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