In February 2008, the State Council approved in principle the formal establishment of major aircraft technology major projects. Premier Wen Jiabao said: The independent development of large aircraft is a major strategic decision made by the CPC Central Committee and the State Council. This means that Chinese people must use their own hands and wisdom to create large aircraft that are competitive in the world. What is competitive? It is to achieve mass production and achieve the three important goals of safety, economy and comfort, and to be competitive in domestic and international markets. It's not easy to make a big plane, breaking through many key technologies, especially engines, materials and electronics.
On May 11, China Commercial Aircraft Co., Ltd. was formally established in Shanghai, marking the official launch of China's large passenger aircraft development project. China Commercial Aircraft Corporation is mainly engaged in the design, development, production, manufacture and processing of aircraft parts for civil aircraft.
Through the development of regional passenger aircraft, China has accumulated certain experience in talents, technology, materials, manufacturing, project management, etc., laying a solid foundation for the next step of developing large aircraft. At present, some aircraft manufacturing enterprises in China are producing key components for Boeing, Airbus and other companies, and to some extent have the ability to manufacture large aircraft.
The development of large aircraft focuses on strengthening the capabilities of aircraft R&D, key component manufacturing, final assembly, marketing, etc., and must break through key core technologies such as aircraft engines, airborne equipment, and materials. The processing of typical and difficult-to-machine materials is also a key component.
How the machine tool industry serves the aviation industry must first understand the structure and process characteristics of aircraft and other aerospace components.
First, the structural characteristics of aircraft parts
The typical structural features of aircraft parts are thin-walled structures with complex shapes, large changes in the shape of the bevel, and the appearance of hyperboloids, requiring precise forming. In order to reduce the weight of the aircraft, increase the maneuverability of the aircraft and increase the payload and range, lightweight design is adopted, and new lightweight materials are widely used. In order to improve part strength and work reliability, the overall blank and the overall thin wall structure are mainly used. A large number of aluminum alloys, titanium alloys, high temperature resistant alloys, high strength steels, composite materials, and the like are now used. The thin-walled parts and honeycomb parts with complicated structure are not only complicated in shape, but also have many holes, holes, grooves, reinforcing ribs, etc., and the process rigidity is poor.
Second, the typical parts that need to be machined in aircraft manufacturing
Typical parts that need to be machined in aircraft manufacturing, mainly aircraft fuselage structural parts and key parts of the engine:
1. Typical parts of the fuselage structure
Typical parts of the aircraft fuselage structure are beams, ribs, ribs, frames, siding, joints, slides and other parts. It is mainly composed of flat parts, elongated parts, multi-chamber parts and ultra-thin wall frame structure. The blanks are sheets, forgings and extruded aluminum alloy profiles. The material utilization rate is only about 5%-10%, and the amount of raw materials removed is large. At present, more than 90% of domestic aircraft parts are aluminum alloy parts, a small amount is stainless steel and titanium alloy steel, and more and more structural parts are used. The application of composite materials is the future development direction.
Structural features of typical parts of fuselage structural parts
(1) The outline size of the piece is getting larger and larger. If any beam parts have a length of 13m.
(2) The angle of the bevel angle of the part changes greatly, and the thin wall and the like. The thinnest part is only about 0.76mm, so the processing rigidity is poor.
(3) The structure of the parts is more and more complicated, and many parts adopt the overall structure.
(4) The dimensional accuracy and surface quality requirements of parts are getting higher and higher. For example, some defects such as burrs appear after machining are not allowed to be manually removed.
Main equipment required to process typical parts of aircraft fuselage
(1) Three-axis machining center, such as large gantry vertical machining center;
(2) Five-axis linkage machining centers, such as large gantry vertical machining centers, shall be equipped with A/B swing angle milling heads or A/C swing angle milling heads;
(3) From the perspective of development, a large gantry-type dual-spindle five-axis machining center is required, and the table size is 5m×20m for processing beam parts;
(4) Processing of aluminum alloy parts requires high-power high-speed machining center, power ≥40kW, spindle speed of 20000r/min or more, with two-axis swing angle milling head;
(5) Due to the large amount of cutting of the whole aluminum alloy parts, in order to facilitate chip removal, it is better to require a horizontal machining center where the table can be turned over 90°. At present, there is no such horizontal machining center in China;
(6) There are many types of aircraft fuselage structural parts, different shapes, and poor process rigidity, which requires a large number of fixtures. In order to reduce costs and shorten the production preparation cycle, various flexible fixtures are required;
(7) Sheet metal forming parts mainly involve the forming of skins such as skins, profiles and pipes, and require precise forming. In order to ensure the manufacturing precision, a large-size skin stretching machine, a skin roll forming machine, a three-axis rolling leveling machine, a profile bending machine, and a duct forming machine are required. Aircraft parts assembly also requires automatic drilling and riveting equipment;
(8) In order to reduce the weight of the aircraft, the application of composite materials is more and more, and the production of composite components requires a tape laying machine, etc. (the tape laying machine is still blank in China).
Next page
3 To 4-Way Ball Valve,1 Inch Stainless Steel Ball Valve,Female Thread 3 Way Ball Valve,Stainless Steel 3 Way Ball Valve
WENZHOU LUWEI VALVES AND FITTINGS CO.,LTD , https://www.stainlesssss.com