Integrated leaf disc multi-axis linkage CNC precision electrolytic machining technology

The combination of high-quality, high-efficiency and low-cost processing methods is the goal that the world's aerospace manufacturing powers are striving for. Especially for difficult-to-machine materials and complex structures, the choice of processing methods has become the guarantee for achieving design goals. The multi-axis CNC precision electrolytic machining technology of EMAG Electrochemical Company of Germany completely replaces the high-speed milling and five-axis EDM process to process the whole leaf disc. The advantages of non-traditional cutting are very obvious.

Addressing the development needs of the aviation industry

According to the latest global civil aviation market forecast released by Airbus in 2012: from 2012 to 2031, the global market demand for new passenger aircraft and freighters will reach 28,200, with a total value of nearly 4 trillion US dollars. Aircraft demand is on the rise. In order to win this huge market share, aircraft manufacturers around the world must fully invest in new and innovative technologies.

It is worth noting that the development of civil aircraft in the world is more concerned with green environmental protection and better economic indicators, and is focused on further improving aerodynamic efficiency, structural efficiency, power system efficiency and equipment reliability to form a breakthrough. Constantly increasing the thrust-to-weight ratio, extending the service life and reducing energy consumption have always been the dominant direction of modern aero engine development, which has led to the emergence and will continue to emerge a large number of new materials and structures in the design of advanced aeroengines.

The integral leaf disc is a typical integral structural component in the design of advanced aero-engines. It integrates the blades and the leaf discs, eliminating the need for conventional blade-jointed boring heads, gutters and locking devices, avoiding the loss of the turbulent airflow and reducing The structural weight and the number of parts greatly improve the engine's working efficiency, thrust-to-weight ratio and reliability. Fans, high-pressure compressor rotors, and even low-pressure turbine rotors, etc., have become the development trend of advanced aero engines.

In the design, in addition to the overall structure, in the material, more advanced composite materials, titanium alloys and nickel-based superalloys. Corresponding to difficult-to-machine materials and complex structures, existing manufacturing techniques often lag behind. Therefore, high-quality, high-efficiency, low-cost and fast-response processing methods are the goals pursued by aviation manufacturers in various countries, and are also the guarantee for achieving design goals.

Multi-axis linkage CNC precision electrolytic machining process with obvious advantages

The overall leaf disc shape is complex, the precision is high, the leaf type is thin, and the deformation is large after the force. The manufacturing technology has become the focus of research in many developed countries. The overall leaf disc processing technology mainly includes: efficient overall milling and multi-axis linkage CNC precision electrolysis.

Compared with the CNC milling method, the overall blade disk electrolytic processing efficiency is high, the electrode (tool) has no loss, and the processed thin structure has no residual stress and deformation. The advantages of high-quality and high-efficiency electrolytic processing in mass production are more prominent. As a technology leader in the field of electrochemical machining, EMAG Electrochemical Machining Machine Co., Ltd. has become one of the world's first seven-axis CNC high-frequency narrow-pulse precision vibration electrolysis machine tools for aerospace engines with its patented technology in the field. European equipment manufacturer of the whole leaf disc.

The precision electrolytic machining process (PECM) is derived from ordinary electrolytic machining (ECM), and the machining gap between the machining cathode and the workpiece to be machined is many times smaller than the latter, so that good copying from the cathode to the workpiece can be achieved. . It should be emphasized that EMAG Electrochemical Company has developed its own independent cathode design software, which can automatically compensate the inlet and exhaust R angles of the blades and the relative profile area during the precision electrolysis process. In addition, the electrolysis process itself does not produce any cathode consumption even when processing an integral blade of a superhard material such as a nickel-based alloy compared to a conventional numerically controlled milling process. Compared with the high-efficiency integral milling calculation and high overall processing cost, EMAG multi-axis CNC precision electrolytic machining technology can process several times more efficiently than machining, but the cost can be reduced by several orders of magnitude.

Figure 1 Overall leaf disk simulation
1. Variable stator blade 2. Compressor impeller 3. Combustion chamber 4. Power turbine
5. Gas turbine 6. Compressor 7. Power output drive shaft

The best processing technology for the whole leaf disc of superalloy material

High-efficiency precision electrolytic machining is an important way to realize the whole leaf disc processing of high-temperature alloys. The precision vibration electrolysis processing of high-temperature alloy whole leaf discs has become an important technology for the research and application of major aero-engine companies. It is to realize the processing of high-temperature alloy whole leaf discs. It is the most feasible and has an effective process for successful foreign examples.

Germany EMAG Electrochemical Company multi-axis linkage CNC precision electrolytic processing technology, combining the technical characteristics of multi-axis CNC CNC machining center and precision electrolytic machining, tool cathode without loss, no macro cutting force, especially suitable for processing compressor end High-temperature zone high-temperature alloy or titanium alloy with variable cross-section twisted blades for difficult overall leaf discs.

Now, some advanced aircraft in China have begun to apply difficult-to-machine nickel-base superalloy materials to the compressor's overall blade disc in high-push-to-weight ratio engine design. The speciality of the high-temperature alloy whole leaf disc is that the machinability of the material is very poor, the processing deformation and the serious consumption of the tool, which is greatly affected by the processing efficiency and the processing cost. Modern manufacturing technology must consider the single-piece manufacturing of the engine development stage, but also consider the efficiency and technical economic needs of mass production. EMAG multi-axis linkage CNC precision electrolytic machining technology can effectively solve the high-efficiency machining problem of high-temperature alloy whole leaf disc in high-performance engine in China. The latest development of PO 900 BF multi-axis linkage high-frequency narrow pulse precision electrolytic machining The center can finally reach the contour profile of the blade profile ≤0.06mm, and the surface roughness value of the general superalloy material is Ra≤0.2μm.

Complete process chain - turnkey solution

EMAG electrolytic processing technology provides an independent and economical manufacturing process, tailor-made for customers to shorten the process path, to maximize the benefits for customers. EMAG's newly developed PO 900 BF multi-axis linkage high-frequency narrow-pulse precision electrolytic machining center and a complete turnkey solution – from the initial forming of the entire blade blank blank processing (large amount of material removal, preliminary selective implementation of the blade Twist angle and blade profile shaping) until the final blade profile is formed into a complete process chain turnkey solution.

Figure 2 EMAG PECM PO 900 BF Precision Five-Axis Electrolysis Machining Center

EMAG multi-axis linkage CNC precision electrolysis integral leaf disc processing technology uses CNC multi-axis linkage electrolysis process for blade nesting processing, its feed speed is ≤2mm/min, and adopts numerical control multi-axis linkage precision electro-machining process, its feed speed is about It is 0.1~0.2mm/min (the blade processing allowance is 1mm), and it does not have a significant influence on the feed speed due to changes in blade area, material and geometrical dimensions. In addition, the electrolysis process is a complete process, which does not require subsequent polishing and re-processing of the inlet and outlet edges of the blade. It is a tool-free process, and all the blades under the same type of leaf disc can be processed using the same set of cathode tools. use many times. Its advantages in processing cost and processing efficiency will greatly promote the development and application of aero-engine high temperature alloy whole leaf disc. In addition, the investment of EMAG multi-axis linkage CNC precision electrolysis machine tool can be tailored according to the customer's specific processing of the overall leaf disc size and current equipment and electrolyte system.