Application of 3D printing technology for key structural parts in a new generation of manned spacecraft

At 13:49 on May 8, 2020, the return capsule of my country’s new-generation manned spacecraft test ship developed by the Space Technology Research Institute of China Aerospace Science and Technology Corporation successfully landed in the scheduled area of ​​the Dongfeng landing site. The new generation of manned spacecraft is a new generation of space-to-earth shuttle transport aircraft with international advanced level demonstrated for the needs of my country’s manned moon exploration and space station operation. The complete success of this test ship flight mission indicates that China’s new generation of manned spacecraft has taken shape, and it also marks important breakthroughs in a large number of new technologies in the fields of cabin structure, materials, and control systems. One of the important technological breakthroughs is the design and molding technology of the super-large integral titanium frame led by the General Department of the Fifth Aerospace Academy. The super-large overall titanium frame structure is all manufactured by 3D Printing technology, successfully achieving the goals of reducing weight, shortening the cycle, and reducing costs. The successful return of the new generation of manned spacecraft test ship also marks the passing of the big test for the overall 3D printing technology of the super-large key structural parts.

During the return process of the new generation of manned spacecraft, the heat-resistant large bottom will withstand the worst aerodynamic force and aerodynamic heat. The heat-resistant outsole frame structure is the most important bearing component under the action of aerodynamic heat. Due to the large size of the titanium alloy frame, the cost is extremely high if the traditional forging process is used. At the same time, the design plan needs to be continuously adjusted and iterated, making the originally extremely tight development cycle stretched. The design team headed by Ma Bin, General Department of the Fifth Academy of Aerospace, decided to adopt the idea of ​​”refining into parts” and try to use laser deposition 3D printing technology to achieve the design goal of “good, fast and cheap”. This technology can not only adapt to the rapid optimization and iteration of the design plan, and realize the lightweight design corresponding to the load distribution; but also can simultaneously carry out the research on the 3D printing process of the super-large titanium frame, shorten the development cycle, increase the development yield, and greatly reduce the production cost. Xinjinghe Laser Technology Development Co., Ltd. is a private enterprise that undertakes the additive manufacturing of the heat-resistant outsole frame. The chairman of the group Li Cheng introduced that the manufacturing of high-performance large-scale key metal structural parts can be said to be the “ghost gate of metal 3D printing technology”. “On the one hand, due to the oversized parts, the internal thermal stress has risen exponentially, deformation and even cracking have become the nightmare of metal additive manufacturing technology; on the other hand, if the solidification and cooling processes cannot be controlled, metallurgical defects will occur. In terms of key structural parts, metallurgical defects are an unacceptable problem.

After more than ten years of exploration and accumulation, Xinjinghe has made a major breakthrough in the metal 3D printing technology of laser deposition manufacturing. The super-large overall titanium frame was successfully printed and applied, instead of its comprehensive independent development from equipment development and production to material process parameter research and development. Control is closely related. During this printing process, Xinjinghe fully tapped the process potential of the domestically developed LiM-S2510 equipment, and combined with strong process design and post-processing capabilities, finally realized the defect-free manufacturing of the structure. The picture below shows the LiM-S2510 equipment developed by Tianjin Leiming Laser Technology Co., Ltd. used in the project. Its self-developed process control software also played a key role in the process of this project.

At present, laser deposition manufacturing technology is increasingly being used in the aerospace field. Through the continuous deepening of the understanding of additive manufacturing technology, my country’s metal manufacturing industry is bound to undergo essential changes. First, the material metallurgical technology will change, which is reflected in that the preparation and performance of materials will get rid of the principle constraints of traditional metallurgical processes, and realize the intelligent preparation of high-performance new materials such as non-equilibrium, gradient, and refractory materials. The manufacturing process is the metallurgical process. The second is that the structure and performance of major equipment will change, and the lightweight and integration of structural parts will reach a new level; the third is that the manufacturing model of large-scale products will change, and the production will be brought about by the size of the parts. Restrictions such as high investment and long cycle have been broken through, and the development of large-scale new products will enable rapid, low-cost, digital/intelligent manufacturing.  “You can go to the moon for nine days, you can go to the oceans to catch turtles, and you can talk and laugh. There is nothing difficult in the world, as long as you are willing to climb.” The safe return of the new generation of manned spacecraft’s return cabin means that countless new technologies and new processes are flourishing in the hands of the Chinese people. It means that “Made in China” will surely enter a new era of “Created in China”, and even more so. No difficulty can stop the great journey of the Chinese nation to realize the Chinese dream!