Engine blades are a type of typical free-form surface parts. When machining such parts, they have a characteristic: thin, easy to deform during machining, and the material is usually stainless steel, Monel, INCONEL, titanium and nickel-based difficult-to-machine alloy materials , It increases the difficulty of processing.
Another processing method is the integral processing of blades and blisks. Internationally,ACAM-A R&D member of the Aachen Additive Manufacturing Center, a turbomachinery expert from the RWTH Aachen University Digital Additive Manufacturing DAP, and Fraunhofer Fraunhofer Institute for Production Technology IPT. The integrated blisk is made of nickel-based super alloy IN 718 As a result, the researchers successfully developed the LPBF manufacturing process for the blisk. As a result, they manufactured the blisk with a contour close to the final shape, especially the blade contour, which greatly reduced the material to be removed.
In this issue, 3D Science Valley and Gu You come to appreciate the latest situation of domestic development of engine blades and impellers.
Whole leaf disc.Source: ACAM Aachen Additive Manufacturing Center
3D printingThe world of blades that quietly changed
l China Aviation Development Commercial Aviation Engine
-Additive manufacturing of stator guide blades with cell structure
According to the CN209569034U patent of China Aviation Development Commercial Aviation Engine, China Aviation Development Commercial Aviation Engine has developed stator guide vanes with outer ring mounting edges at both ends. The design of the outer ring mounting edge includes the filling material of the cell structure and the new type of stator guide. The structure design of the blade and the aero engine including the side body eliminates the liner structure, achieving the same or better goal of reducing fretting wear and reducing aerodynamic loss (without changing the structure of other parts).
The internal thermal expansion of the mounting side adopts a cell structure design, which can be equivalent to the working state of the gasket structure. But with clearance fit, it is easy to install in cold state, and expand and compress under working temperature. By filling a suitable material with a larger thermal expansion coefficient inside the mounting edge cell structure, it can be achieved that the thermal expansion deformation can achieve the expected effect, and the stress level is within a controllable range.
-Impact-resistant enhanced turbine engine fan blades
Based on the characteristics of additive manufacturing that can integrate multiple materials and flexible internal structure design, it can effectively improve the impact resistance of the blade by strengthening the structural design of the leading edge of the blade under the premise of reducing the weight of the blade to the greatest extent. According to the CN105604978B patent of China Aviation Development Commercial Aviation Engine, China Aviation Development Commercial Aviation Engine has developed an impact-resistant enhanced turbine engine fan blade, including the blade body and the leading edge enhanced structure.
The blade body and the leading edge reinforcement structure are integral parts formed by an additive manufacturing process. The blade body is a metal blade, and the leading edge reinforcement structure is made of high-strength metal materials. Among them, the leading edge enhancement structure includes an elastic layered structure that expands outward along the entire longitudinal length on the leading edge side of the blade body. Reinforced structures are transitioned with intermediate materials that have affinity.
It is worth mentioning that internationally, Avio Aero, a subsidiary of GE Aviation, has expanded the GE9X engine turbine blades at the Cameri plant in Italy.3D printingProduction capacity, the factory has installed 35 electron beam melting (EBM) metal3D printingThe equipment is expected to produce about 60,000 blades here from 2022 to 2023.
video:GE9X engine
l China Aviation Development Beijing Institute of Aeronautical Materials
-Whole leaf disc
According to the patent CN107138924A of the Beijing Aviation Materials Research Institute of China Aviation Development, the current domestic and foreign bimetal dual performance titanium alloy blisk manufacturing methods include linear friction welding, diffusion welding, hot isostatic pressure diffusion welding or powder feeding laser additive manufacturing methods. . Among them, the linear friction welding process depends on the equipment to a great extent, the welding effect and accuracy largely depend on the capabilities of the equipment, and the welding tooling is complicated and the cost is high. The diffusion welding method faces technical difficulties such as difficulty in pressurization, joint consistency control and non-destructive testing, and the overall blisk structure is complex, requiring special pressurization methods, and the process is technically difficult to realize. The maturity of hot isostatic pressing diffusion welding technology is relatively low, and reliable sealing or sheathing needs to be solved, and special process measures need to be taken to ensure the reliable implementation of the hot isostatic pressing process. In addition, since the structure needs to go through the welding thermal cycle process as a whole during diffusion welding, it is also necessary to solve the problem of matching the welding thermal cycle with the heat treatment system of the material to avoid the adverse effects that the thermal cycle may cause on the base material.
China Aviation Development Beijing Institute of Aeronautical Materials has developed a bimetallic dual-performance titanium alloy blisk manufacturing method. First, on the basis of the wheel disc forgings, electron beam fuse deposition additive manufacturing methods are used to manufacture titanium alloy blade blanks of different materials. ; Then use mechanical processing or electrochemical processing to the blade design size, and finally realize the manufacture of bimetal dual performance titanium alloy blisk. This method has the characteristics of low manufacturing cost, short cycle and high metallurgical quality. The use of different materials for blades and discs can give full play to the advantages of their respective mechanical properties and meet the requirements of the overall blisk for high-strength and high-strain fatigue performance of the discs and the high-stress fatigue and durability requirements of the blades for the blades, thereby realizing the overall blisk Serve under higher temperature conditions or replace the high-temperature alloy blisk to achieve the purpose of weight reduction.
This is the same internationallyACAMThe integrated blisk developed by the interdisciplinary team of the Aachen Additive Manufacturing Center uses different technologies. ACAM developed the LPBF-based powder bed additive manufacturing process for the blisk. In addition, they applied a lattice structure to support the blisk. The components in the construction process significantly reduce the material that needs to be removed later and avoid vibration during the milling process. Those lattice structures can be easily removed due to their low density.
Both domestic and international twists and turns pave the way for continuous exploration of additive manufacturing of blisks.
l Southern University of Science and Technology
-Remanufacturing of aero engine fan blades
According to the patent CN106874550A of Southern University of Science and Technology, Southern University of Science and Technology has developed a remanufacturing method for aero-engine fan blades based on additive design. Without changing the aerodynamic shape and functional characteristics of the aero-engine fan blades, it adopts a subsurface fine mesh structure design. , The spherical hollow unit is introduced, and a spherical hollow network structure that meets the structural integrity requirements is formed inside the aero-engine fan blade through multiple spherical hollow units, and finally the remanufacturing is completed using additive manufacturing technology. This method can reduce the weight of aero-engine fan blades and solve the problem of stress concentration at the root of aero-engine fan blades. At the same time, the additive manufacturing process is simple, the manufacturing cycle is shorter, and the cost is lower. Southern University of Science and Technology has changed the traditional diffusion bonding manufacturing process that is complicated and difficult to operate, and has given full play to the role of additive design and manufacturing in the remanufacturing of aero-engine fan blades.
Finally, it is worth noting that as the 3D Science Valley in the “3D printingAs mentioned in the book “Industrial Manufacturing”, “3D printing is not an island, but must be integrated with other traditional manufacturing processes in order to become a “weapon” for creating added value in the manufacturing industry. In terms of process integration, we can learn from the experience includeGF processing solutionThe extensive product portfolio provided provides a one-stop solution from a combination of manufacturing technologies such as electrical machining (EDM), milling machines, laser texturing, additive manufacturing, etc., thereby providing flexibility in production, reducing complexity, and reducing overall costs ( TCO).AnotherRenishawIt integrates a complete process chain solution, including its unique in-machine probe measurement, tool setting and Equator comparison measurement, etc. These technologies will definitely improve the automation level of the factory, so that manufacturing companies can have immediate satisfaction The high-efficiency precision manufacturing capabilities required by the “Factory of the Future”.
Inside the blade
Impeller blades are high value-added products. In addition to the integration of hardware, it is true that breaking through traditional design ideas and manufacturing methods requires enterprises to have the spirit of self-transcendence.Simulation and designWill play an increasingly important leading role to guide the direction of the manufacturing industryForward designthe road.
Siemens3D printingGas turbine blades
Really understand3D printingAfter the value of this technology, we found that the attitude of domestic enterprises towards this technology has undergone tremendous changes.What is gratifying is that these domestic enterprises and research structures have clearly seen3D printingReshaping the subversive potential of the value chain industry chain, I believe that with the full integration and interaction of various technologies of international and domestic hardware and software solutions, my country’s manufacturing will open up a unique development path for the benefit of human society.
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