![<?echo $_SERVER['SERVER_NAME'];?>](/template/twentyseventeen/skin/images/header.jpg)
After half a century of development, there is still a certain gap between China's aircraft manufacturing scientific research capabilities and the world's advanced level. In particular, the key technologies for aircraft manufacturing have yet to be broken, design talents have faults, risks are high, and capital shortages are severely constrained by the industry. Further development and quality improvement.
Aircraft body manufacturing is subject to process preparation, manufacturing of process equipment, preparation of blanks, processing, assembly and inspection of parts. Process preparation includes the coordination of manufacturing methods and the determination of coordination routes (see coordination techniques), the design of process equipment, etc. The main materials of the aircraft body are aluminum alloy, titanium alloy, magnesium alloy, etc., which are mostly supplied by metallurgical factories in the form of plates, profiles and pipes. There are also a large number of forgings and castings on the aircraft, such as the fuselage reinforcement frame, the wing spar and the ribs are mostly forged with high-strength aluminum alloy and alloy steel. These large forgings should be between 300 and 700 megatons (3 to 70,000 tons of force). The giant hydraulic press is forged and formed.
Digital three-dimensional design
After long-term 3D process design and simulation, CAX/CAPP/MES system integration and other technologies, domestic aircraft manufacturers have broken through the definition of model-based definition (MBD), 3D process design visualization, 3D assembly process simulation verification and optimization, 3D work. Key technical bottlenecks such as the creation, distribution and browsing of instructions, multi-system integration and business process optimization, and the construction of a complete system that can support the assembly, machining, sheet metal, metallurgical and other process design business needs. The integrated enterprise-level digital process design platform has realized the successful transformation of the traditional two-dimensional process design and manufacturing system to the three-dimensional digital process design and manufacturing system.
At the overall design stage of the aircraft, the manufacturing company has begun to design the overall process plan, and through the use of a maturity-based collaborative process review method, based on the design results, simultaneous follow-up process planning, including assembly coordination, part manufacturing technology, process separation surface The definition and preparation of a series of process guidance documents such as component assembly charts.
In 3D process mode, 3D data (models, etc.) replaces 2D engineering drawings and paper process instructions. The three-dimensional process electronic data package (instruction) becomes the technical basis for the production site work. Through the integration of the process design platform and the production management system, the process data information such as the three-dimensional process instruction is distributed to the workshop production site, and the three-dimensional, dynamic and interactive The customized interface displays and describes the process, effectively integrates the production process, personnel, equipment, tooling and tools, and displays the product design relationship, process structure relationship and geometric model through an intuitive interface, showing the process simulation process and The tooling uses the positioning method to display the operation instructions corresponding to the simulation process, so that the workers can operate according to the instructions, accurately and quickly refer to the information required in the process, and improve the accuracy and efficiency of the work.
3D process design and simulation, process visualization technology based on lightweight model and application of CAX/PDM/MES multi-system integration technology, effectively shorten product development cycle, improve product quality and production efficiency, truly realize no 2D drawings, no The three-dimensional digital integrated manufacturing of paper work instructions effectively improves the working environment of the production site, makes field workers easy to understand, reduces operational errors, and improves product quality and production efficiency. The in-depth application of 3D digital process design technology will certainly promote the rapid development of China's aircraft manufacturing industry.
Component machining
The process equipment in the aircraft manufacturing industry generally refers to machining jigs, assembly frames, sheet metal molds, welding fixtures, measurement and inspection fixtures, and the like. Machining is the most important method to obtain the final shape and accuracy of aircraft parts, and machine tool fixtures play an important role in ensuring the machining quality and machining efficiency of aircraft parts.
The flexibility of aircraft manufacturing process equipment has always been an urgent problem for the aviation industry, so it has received extensive attention from the industry and has carried out a lot of research. Flexible tooling is based on the product digital size coordination system, using a reconfigurable modular structure of tooling, high degree of automation. The purpose of the flexible tooling system is to reduce the cost of tooling manufacturing, shorten the tooling preparation cycle, and significantly increase productivity.
CNC machining, especially CNC milling, is currently the main method for mechanical machining of aircraft structural parts. High-speed cutting methods are widely used. For example, large-scale complex structural components of Xifei are processed at Xifei CNC Center. The types of structural components include wing girders, siding, inter-beam ribs, frames, large-scale support joints and butt joints. In addition to the characteristics of many slots, thin wall thickness and high precision, the parts need to meet the general characteristics of aircraft wing structural parts such as aircraft bevel angle theoretical surfaces, and also have large part contour size, groove depth and reference plane profile requirements. Strict and other characteristics.
In order to ensure the quality of the processing, special fixtures have been developed for each part. The base is a relatively bulky casting and the positioning accuracy is not high. The workshop tool library and even the workshop floor are full of various types of fixtures. When converting from one part to another, the recombination conversion time of the fixture is about 2h, which seriously affects the production efficiency. Large monolithic structural parts on aircraft, such as integral skins and siding, are still partially milled and trimmed with large die tires.
CNC machining of aircraft structural parts should have flexible fixtures as a guarantee of processing quality and processing efficiency. Group fixtures and assembly fixtures are important means of implementing flexible fixtures. Computer-aided fixture assembly planning and fixture production process management are important functional modules in the flexible fixture system and must be well resolved. Flexible clamps should generally have pneumatic or hydraulic clamping functions and be integrated with the CNC machine in structure and control.
Laser welding technology
Large aircraft body manufacturing uses a large number of welding structures and welding products. The selection of welding methods is mainly concentrated on traditional welding technology, and new welding technology has also been applied. Especially the friction stir welding technology is applied to the manufacture of aircraft products for the first time.
In the large aircraft manufacturing process, welding technology is a very important part of the connection technology, an important part of the manufacturing technology, and also an indispensable technology in the manufacture of aircraft bodies and engine containers, pipelines and some precision devices. In the manufacturing field, more and more products use various welding methods to join parts of different materials, shapes, structures and functions into a complex whole, which greatly simplifies the overall processing of the components.
In the development of large aircraft bodies, a large number of basic researches on laser welding have been carried out in a targeted manner. For stainless steel thin-walled large-scale complex structural parts, the shape is hyperbolic complex structure, large size, long weld seam, the part is welded by manual TIG welding process, the welding deformation is very large, the outer surface of the weld is uneven, and the groove is deep. The design quality requirements of the product are not met, and the protruding portion of the inner surface weld is interfered with the assembly, and the assembly is difficult.
At present, foreign countries apply laser welding technology to the splicing of aircraft large skins, skin and long rafts, wing boxes, welding of wings and inner partitions and ribs, etc., using laser welding technology to replace traditional rivets for aluminum alloy aircraft. The manufacture of the fuselage achieves the purpose of reducing the weight of the aircraft body and increasing the strength. This will also be the development trend of domestic laser welding technology in aircraft manufacturing applications.
Digital measurement technology
With the rapid development of science and technology and aircraft digital manufacturing, the aircraft digital measurement technology is more and more widely used in aircraft manufacturing with its advantages of high precision, high efficiency and high automation. Some optical three-dimensional large-size topography detection technologies are becoming more and more mature, and related instruments and equipment such as laser trackers, machine vision measurement systems, iGPS, and lidar scanning measurement systems have been applied in many fields of the aircraft manufacturing industry at home and abroad.
For some large-size, high-precision aircraft or special-type aircraft, China's traditional measurement methods can not meet its requirements, digital measurement technology is the first choice. In particular, the combination of multiple digital measurement systems not only overcomes the contradiction between large measurement range and low measurement accuracy, but also obtains more accurate measurement results, and can meet the requirements of multi-function, and become a key supporting technology in aircraft digital manufacturing. One of them greatly enhances the system's scalability and application range, and plays an important role in improving aircraft manufacturing, assembly quality and efficiency.
In recent years, the successful application of foreign model-based definition technology on the Boeing 787 model has led to the development of integrated design and manufacturing technology. Companies such as Boeing, Airbus and Ford have generally adopted digital measurement equipment-based products for 3D measurement and quality control, established a relatively complete digital measurement technology system, and developed a corresponding computer-aided 3D inspection planning and measurement data analysis system. The corresponding 3D inspection technical specifications have significantly improved the detection efficiency and quality.
Modern advanced aircraft assembly technology has been completely different from traditional aircraft assembly technology, that is, the traditional complex frame is no longer used to position and clamp components for assembly work. Instead, it fully absorbs and utilizes modern high-tech technologies, such as computers, software, laser tracking and positioning, and automation control, to develop into aircraft frameless positioning digital assembly technology, which is mainly used to measure and locate various processes in aircraft assembly lines. Equipment, or the assembled components used directly to locate the aircraft, is an important part of the aircraft's digital assembly system.
The aircraft manufacturing industry is not only related to the development of the national defense aerospace industry, but also an important industry related to the national economic construction. At the same time, due to the wide application of digital measurement technology in the aircraft manufacturing industry, it has become an important symbol of the level of national science and technology and industrial development. Therefore, digital measurement technology has become a necessary trend to promote the development of aircraft manufacturing.
Digital assembly
Combining and connecting various components or components according to design technical requirements to form a high-level assembly to the whole process is the most critical part of the entire aircraft manufacturing process. Aircraft assembly technology has experienced the development process from manual assembly, semi-mechanical/semi-automatic assembly to mechanical/automated assembly. At present, digital assembly technology, which is highly valued by various economic and military developed countries, is becoming the technological high point of modern aircraft manufacturing.
The aircraft digital assembly technology system involves many advanced technologies and equipments such as assembly process planning, digital flexible positioning, assembly hole connection, automatic control, advanced measurement and detection, and system integration control. It is a multidisciplinary intersection of mechanics, electronics, control, and computer. Integrated high-tech integration.
With the rapid development of computer information and network technology, large aircraft companies represented by Boeing, Lockheed Martin and European Airbus have started and adopted aircraft digital assembly technology. The production and development process of new military and civil aircraft such as Boeing 777, A380 and JSF fully reflects the status quo and development trend of digital assembly technology in aircraft manufacturing process in developed countries.
Domestic aircraft assembly, although partially adopting more advanced technology, such as the use of CAD technology, including the establishment of the standard frame library and optimized frame and parameter design, the assembly process of tools, tools and products three-dimensional Simulation, etc., began to use laser measurement + CNC drive positioning, some models also use automatic drilling and riveting technology, but overall there is still a big gap compared with developed countries.
Digital assembly technology represents the development direction of today's aircraft manufacturing, involving comprehensive research and application in multidisciplinary fields such as new materials, communications, machinery, computers, control, electronics, etc., and its research must be related to process technology, experimental technology, testing technology and modern technology. Research on technologies such as management is combined to achieve a shift in production models and methods.
Cold spray technology
Thermal spraying is the most widely used coating preparation technology used by aerospace engine companies at home and abroad. It is mainly used for wear resistance, oxidation resistance, corrosion resistance, wear sealing, thermal barrier, anti-adhesion, anti-friction wear and resistance. Production of fuel and part size repair coatings. Physical vapor deposition technology is used for the preparation of high quality high temperature protective coatings for engine hot end turbine blades and guide vane components. In China, hollow cathode arc ion plating technology is used in the manufacture of MCrAlY and AlSiY anti-oxidation coatings, and electron beam physical vapor deposition technology is used in the production of thermal barrier coatings.
Engine manufacturers need to set up a school-enterprise cooperation and gathering platform, combined with coating production and field issues, strengthen communication with research institutes to take advantage of their coating stress research, and carry out X-ray diffraction, layer-by-layer peeling as soon as possible. Engineering research on coating residual stress testing technology such as drilling and curvature method, and formulating industry standards for coating residual stress testing to better ensure the smooth progress of research and production of new engine coatings in China.
Mismatch strain and thermal gradient due to the quenching stress of the powder particles themselves, the impact stress on the deposited coating, and the difference in thermo-mechanical properties between the coating and the matrix material during melting and deposition of the material from which the coating is prepared Effects, and in some cases subsequent processing and service environments, will inevitably result in large or small residual stresses in the coating.
In recent years, the ColdSpraying technology, which has been developed and matured, can achieve coating deposition at low temperatures. Compared with thermal spraying technology, the cold spraying process has almost no thermal effect on the structure of powder particles. The oxidation can be ignored. Cold spray is a metal spray process, but it is different from traditional thermal spray (overspeed flame spray, plasma spray, explosion spray and other traditional thermal spray), it does not need to melt the sprayed metal particles, so the temperature generated on the surface of the sprayed substrate is not Will exceed 150 degrees Celsius.
Ningxia Carbon
Coal is the dominant mineral resource in Ningxia. The distribution area of coal-bearing strata in this area is 17,000 square kilometers, accounting for a quarter of the total area of Ningxia. coal has been hailed as black gold, industrial food. Elements that form the coal's organic matter are mainly carbon, hydrogen, oxygen, nitrogen and sulfur, in addition, there is a very small amount of phosphorus, fluorine, chlorine and arsenic and other elements.
Ningxia Carbon
NINGXIA PANSON COAL AND CARBON CO., LTD , https://www.nxpanson.com