Additive manufacturing (also known as 3D Printing) technology is a digital, intelligent, low-cost, and short-cycle advanced manufacturing technology that directly realizes the manufacturing of three-dimensional complex structures by simply adding materials layer by layer in two dimensions. It breaks through the principle limitations of traditional parts forming and processing and manufacturing technology. In theory, it does not rely on traditional industrial infrastructure. It can directly manufacture any internal structure, shape, and geometric size through simple “two-dimensional digital printing”. The high-performance three-dimensional complex structure. Precisely because of its transformative advantages compared with traditional forming manufacturing technology, 3D printing technology has become a hot spot in the current technical fields such as advanced equipment manufacturing, structural design, and new materials, and developed countries such as Europe and the United States have included it in their national development strategies.
Metal 3D printing technology belongs to an important branch of 3D printing technology, which has an important role in promoting the manufacture of high-performance metal components. As the main body of the large-scale key bearing structure of the manufacturing industry and major defense equipment, what kind of innovation will occur in the manufacturing of high-performance metal components in this manufacturing revolution? How will metal 3D printing technology be widely used?
In this regard, the reporter interviewed Wang Huaming, an academician of the Chinese Academy of Engineering, director of the National Engineering Laboratory for Additive Manufacturing of Large Metal Components, and a professor at Beijing University of Aeronautics and Astronautics. Give full play to the advantages of new technology “whatever you want” Reporter: Metal can be said to be one of the most common materials in daily life. As far as you know, what are the key constraints of traditional metal manufacturing technology?
Wang Huaming: Due to its special advantages over non-metallic materials, metals are widely used in large-scale key bearing structures of major equipment. However, large ingots are faced with problems such as coarse grains, loose structure, serious chemical composition segregation, and poor plastic forming performance, which will affect the forming and manufacturing capacity and performance of large metal components.
It can be considered that in the past few decades, the manufacturing capacity and performance level of large metal components has actually not made a leap forward. Reporter: The industry generally believes that 3D printing technology will trigger a revolution in manufacturing. How do you think metal 3D printing technology will get rid of the principle constraints of traditional manufacturing? Wang Huaming: Metal 3D printing technology has the characteristics of ultra-high temperature and strong convection “micro-area supernormal metallurgy”, and can make the solidification and cooling rate of metal up to hundreds of thousands of degrees Celsius/sec, and has the characteristics of “chilling and rapid solidification”. The combination of these two characteristics can make metal 3D printing technology completely get rid of the principle constraints of traditional large-scale ingot casting and forging, and enable additive manufacturing of large/super-large, complex/super-complex metal components with fine grains, uniform composition and structure. Dense and rapid solidification structure, and can easily synthesize and prepare a new generation of new metal structure materials that cannot be prepared by traditional metallurgical preparation technology. The internal quality, grain structure, microstructure and performance of components manufactured using metal 3D printing technology are not only affected by the size, wall thickness, and position of the parts, but also in the 3D printing process where the metal components are melted layer by layer and solidified layer by layer. In the process, you can also control the melt metallurgical state, solidification cooling rate, temperature gradient and other metal crystallization conditions of the 3D printing alloy molten pool “as you want”, and the physical and chemical conditions of the 3D printing environment in the process of solid cooling, etc., to achieve different parts of the part. Active control of the chemical composition, grain size, morphology, orientation and microstructure of the material, to give full play to the performance advantages of different materials, to complement each other, to “design on demand” different materials, and customize them to different parts of the part to make the additive manufacturing gradient Metal material components have special properties that a single material cannot have.
Reporter: Could you please talk specifically about the impact of metal 3D printing technology on daily life? Wang Huaming: As far as aircraft manufacturing is concerned, there are currently tens of thousands of structural parts for a large passenger aircraft.
In the future, if metal 3D printing technology is used to produce large, complex, integral, high-performance, and lightweight components, the number of fuselage structural parts for a large aircraft may only be hundreds, which can transform the weight of the aircraft itself. Moreover, under traditional circumstances, aircraft production requires the support of strong national heavy industry capabilities, and the design time ranges from five years to more than ten years. In the future, the use of metal 3D printing technology in conjunction with simulation technology may reduce the development and production cycle of aircraft by orders of magnitude. If we can make full use of the advantages of low-cost, short-period, digital, and intelligent metal 3D printing technology, it may be useful for the preparation technology of high-performance metal structure materials, high-performance large-scale and complex integral key metal component manufacturing technology, and structural design technology for major equipment in the future. , And even have a transformative impact on the equipment production model. We still need to achieve breakthroughs in many aspects. Reporter: As you said, metal 3D printing technology does have many advantages that traditional manufacturing technologies cannot match. There are not many applications in the promotion. In order to promote widespread application, what areas should our country focus on? Wang Huaming: The future development of metal 3D printing technology and its role in major equipment depend on the level of research on basic issues such as key science and alloy technology in the metal additive manufacturing process. At present, metal 3D printing technologies mainly include “powder bed selective melting” technology and powder/wire feeding “melting deposition” technology. “Powder bed selective melting” technology is suitable for the manufacture of small and complex components, but if you want to obtain a large number of applications in equipment manufacturing, you must make major breakthroughs in process, equipment, materials, quality performance control, etc., and completely solve the problem of the size of printed parts. Limitations, low printing efficiency, poor quality and performance of parts, ultra-high price of parts and other bottlenecks, otherwise the technology can only be limited to very limited special equipment manufacturing. Although the “melted deposition” technology is suitable for the manufacture of large key load-bearing components for major equipment, it is more technically difficult. Therefore, in-depth research on the basic issues of the preparation and forming of meta-materials such as molten pool metallurgy, solidification, thermophysics, and solid-state phase transition in the melting deposition printing process, develop high-efficiency, high-precision, high-performance additive manufacturing technology for large-scale key metal components, and research and develop based on A new generation of high-performance metal structure new materials of additive micro-area metallurgy is an important development direction of this technology.
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