Standing in front of the 3.07-meter-high C919 central flange, Yang Wei, chief engineer of the F-20, stared for a long time ... What made him particularly sighed is that this is a metal 3D printing technology with full intellectual property rights in China. "The large domestic aircraft parts that came out.
The flower of cutting-edge technology "red" after industry-university-research
This titanium alloy C919 central flange, with a size of 3.07 meters and a weight of 196 kilograms, was successfully printed in January 2012. It passed the performance test of COMAC in the same year, and was successfully applied to the first domestically produced large aircraft C919 verification machine in 2013.
This is the first time that domestic models have used 3D printing technology to prepare load-bearing components in the design verification stage, and it is also the first time in the design and production of international civil aircraft. More importantly, as a key part of the wing, with China's manufacturing capacity at that time, it was not possible to forge such a large-scale complex structural part. And if you purchase from abroad, it will inevitably affect the localization rate of large aircraft.
"Metal 3D printing technology provides a new technical approach for the processing of titanium alloy parts and also opens a new window for China's aviation manufacturing." The technology developer and professor of Northwestern Polytechnical University Huang Weidong told the author.
The scientific name of "3D printing" is "additive manufacturing technology". The principle is to decompose the three-dimensional model designed by the computer into several layers of planar slices, and then stack the materials to be "printed" layer by layer according to the slice graphics, and finally "stack" into a complete object.
The manufacture of the central flange for the C919 is typical of the application of metal 3D printing technology in the field of aviation. Huang Weidong and his team applied the technology to print metal materials and parts, which have been widely used in China's missiles, aircrafts, rockets, satellites, aero engines and other fields. Only 20,000 domestic aircraft have been prepared. Parts, most of which have been installed and used.

As early as the early 1990s, Huang Weidong paid attention to the "3D printing technology" that enables rapid prototyping and rapid prototyping. With the support of his classmate of Northwestern Polytechnical University undergraduate classmate and entrepreneur Zeng Shengyang, he has been studying metal 3D printing technology for more than 20 years and has made major breakthroughs.
In July 2011, in response to COMAC's business cooperation requirements, Northwestern Polytechnical University, together with Zhe Shengyang and Huang Weidong, jointly established Xi'an Polytech Additive Technology Co., Ltd., a joint-stock enterprise controlled by Northwestern Polytechnical University technology. Northwestern Polytechnical University and Huang Weidong provided technology and Zhe Shengyang provided funds. Huang Weidong served as chairman and Zhe Shengyang served as vice chairman.
School-enterprise cooperation with clear property rights and clear responsibilities and rights has promoted this cutting-edge achievement to accelerate the integration of production, education and research. Its most iconic achievement is the 3.07-meter-high C919 central flange.
Recalling this "fate", Huang Weidong and others have been impressed so far. In early 2011, the "subject team" received a task to print a central flange for the C919. They worked hard and fought day and night. In less than one year, they built a modern factory in the old teaching experimental workshop, developed special equipment for metal 3D printing, completed a series of highly demanding performance tests, and set up Xi'an Polytech. The company and completed the preparation of printing the margin in early 2012.
Since then, more than 20 people in the team worked overtime and raced against time. Finally, in the morning of January 22, 2012, they successfully printed the first C919 central flange. "That day was the thirtieth year of the New Year." At noon on the day, Zhou Yao and academician of Northwestern Polytechnical University excitedly banqueted the attacking team to have a reunion dinner. "The reunion dinner was eaten from noon until the 30th year of the New Year. More! "After eating and drinking, it is the first day of the new year. Zhao Xiaoming, a member of the team, remembered that the New Year's products have not yet been purchased.
After corporatization, Huang Weidong's team's metal 3D printing technology has made rapid progress in scientific research, and industrialization has also progressed rapidly. In 2018, this technology has been applied to more than 200 units such as COMAC, AVIC, China Aviation Development, China Aerospace Science and Industry, China Aerospace Science and Technology, etc. , Engine, rocket and satellite.
Industry leaders attract "Airbus"
In March 2017, at the Asian 3D Printing and Additive Manufacturing Expo held in Shanghai, an oversized aero engine blade attracted the attention of visitors.
This 933 cm part is currently the world's largest forming titanium alloy part printed by SLM (Powder Laying) technology. The weight of the blade is equivalent to that of the carbon fiber composite blade of the same size, but the lateral performance is better, and the integral shape also greatly improves the reliability of the part.
The production of key components of aero engines is extremely difficult with traditional technology. Huang Weidong's team's metal 3D printing technology simplifies production. All it takes is a computer to design a printing program and print the layers one by one.
Huang Weidong told the author that the advantages of metal 3D printing technology are that it can produce almost any complex structure parts, which is comparable to non-traditional technology. At the same time, its lightweight and topological optimization characteristics can also achieve considerable weight reduction for materials. It is particularly important in the aerospace field where the weight is calculated.
In addition, aerospace parts have complex structures and high costs. Once defects or defects appear, they can only be replaced as a whole, which may cause inestimable losses. However, through metal 3D printing technology, the defect can be repaired into a complete shape with the same material, and the performance after repair is not affected, which greatly saves time and money.
At the same time, they have also developed laser metal 3D printing commercial equipment, which makes Polylite not only the largest metal 3D printed parts processor in China, but also the most technologically advanced metal 3D printing high-end equipment manufacturer.
"We only work with the best teams in the world." In March 2014, Airbus Europe signed a cooperation agreement with Northwestern Polytechnical University and Platinum to jointly develop the application of laser stereoforming technology (a type of laser 3D printing technology) in the aerospace field.
Airbus took the initiative to ask for cooperation. One was that the company had a "best" scientific research team, and the other was that the company had a "best" operating team.
Polytech's technology comes from Northwestern Polytechnical University, relying on the State Key Laboratory of Solidification Technology and Laser Manufacturing Engineering Center of Northwestern Polytechnical University, and has strong scientific research strength; it has a high-tech elite scientific research team, and R & D personnel account for 40% of the entire staff More than 30% of employees have a master's degree or higher.
The operating mechanism of Polytech is unique. Although the joint technology shares owned by Northwestern Polytechnical University and Huang Weidong accounted for 51%, and Huang Weidong served as the company's chairman, the actual controller of the company was Han Shengyang, who knew how the company would operate. Orson has one vote of veto on major issues of the company, and grasps the company's operating direction.
"Let the professor do the professor's job, let the entrepreneur do the entrepreneur's job," said Zhe Shengyang, who has been a scientific researcher and a science and technology management cadre for more than 20 years. When there is a major dispute in the company, Orson's "last vote" is particularly important.
At that time, after the production of laser metal 3D printing equipment, most people thought that they should not put their "cornucopia" on the market and give it to others. From the perspective of the long-term development of the company, Orsun believes that it should be sold, and the market should be enlarged together before the company can walk on multiple legs. After a fierce quarrel, Orson used his veto power to boldly push the company to bring the equipment to the market. This was how the equipment was sold in many units and enterprises and successfully exported to France and Germany.
In 2018, Platinum passed the IPCA certification of Airbus, launched the Airbus A330 additive manufacturing project, and became the only qualified supplier of metal additive manufacturing in Airbus Asia. In August of the same year, Airbus signed joint scientific research cooperation agreements with Northwestern Polytechnical University and Polytech respectively, and the three parties entered the era of joint research and development.
Make design more free, make manufacturing easier
In 2014, Yang Wei, chief of the F-20, made a special trip to Northwestern Polytechnical University to inspect metal 3D printing technology. Next to the 3.07-meter-high C919 central flange, some metal 3D printed parts specially made for the J-20 were also exhibited. Yang Wei looked and looked, touched and touched, with emotion.
The reason why Wei is shocked by metal 3D printing technology is that design has always been limited by production technology and production technology. In terms of aircraft design, even with the best aerodynamic design and the best overall performance design, if no company can produce it, no factory can process suitable components, no matter how good the design is, it ’s no good. ——Metal 3D printing technology has solved and is solving this problem.
Made by humans, the earliest beginnings of stone tools made by primitive people. This is exactly the "reduced material manufacturing" that has continued for millions of years and continues to the present day, that is, the redundant part is continuously removed. Cutting, cutting, drilling, milling and other processes in the era of mechanical manufacturing, including cold machining of precision CNC machine tools, are "reduced material manufacturing." After the fire, the forging, hammering, hammering, and hammering, which are hot-worked, belong to "equal material manufacturing". The most typical and simple is the blacksmith to iron.
There are limitations both in subtractive manufacturing and isomaterial manufacturing: First, it is not possible to process complex parts as a whole, and it is necessary for the husband to produce parts with different structures, and then riveting or welding, or connecting or connecting, which is time-consuming Second, it is impossible to process ultra-profiled, ultra-complex and ultra-thin-walled structures at all; third, it is difficult to reduce weight for parts.
And these, metal 3D printing technology can be overcome. "Maybe one day, we will even print out a complete set of aero engines." Zhao Xiaoming, a team member and the company's chief engineer, was full of passion.
Compared to subtractive manufacturing and isomaterial manufacturing, additive manufacturing is undoubtedly a huge revolution.
Huang Weidong said that during the design verification phase of C919, the successful trial production of the central flanges made a huge contribution. The manufacturing process that can be completed in 6 months using traditional craftsmanship took only 5 days with metal 3D printing technology. The raw material titanium alloy coating powder has almost no waste.
Xue Lei, a doctoral student of Huang Weidong and general manager of Platinum, said that 3D printed honeycomb metal structures can be widely used in materials with extremely strict requirements for materials due to their good mechanical properties, light weight and topological optimization. Aerospace and aviation. For example, replacing the materials of wing and fuselage produced by traditional technology, while sturdy and strong, greatly reduces the weight of aerospace equipment, designers no longer have to sacrifice aircraft performance and sacrificing weapon mounting for weight reduction.
Xue Lei introduced that they currently print more than 20,000 parts and components in the field of aerospace and aviation. While optimizing the product structure and improving their functions, they have achieved overall structural weight reductions of up to 60%.
"Metal 3D printing is creating a grand new world. Today, this grand new world just shows a touch of dawn." According to Huang Weidong, the invention of thermal processing has made mankind from the "stone age" into the "metal age" The invention of cold working has pushed mankind into the "complex age of machinery", and additive manufacturing is bound to make another great leap in human manufacturing capabilities.
"It will drive humans into a new era of" free design ", and fundamentally change the manufacturing method, and promote further great changes in society." Huang Weidong and Xue Lei told the author that the revolutionary metal 3D printing technology will "let design "Freer and simpler manufacturing" will make up for the shortcomings and shortcomings of China's traditional metal processing industry and help China's industrial manufacturing complete the transition from "machining" to "intelligent manufacturing".