The hottest laser technology helps China's aerospa

2022-08-12
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Laser technology helps China's aerospace industry

with the launch of "Tiangong-1", China's aerospace technology has reached a new level. As one of the most advanced manufacturing and processing technologies in the world, laser technology plays an important role in promoting the rapid development of China's aerospace industry. Laser technology has been widely used in the target aircraft of "Tiangong-1" and the previous "Shenzhou-7" spacecraft, "Chang'e to the moon" program, "big plane" program, manned space engineering, etc

the following will introduce the application of several laser processing technologies in the aerospace industry:

smelting equipment and hot rolling mills can be manufactured domestically (I) laser welding technology:

this is the most widely used technology in the aerospace field, because laser welding has its own unique advantages over electron beam, plasma beam and traditional welding methods:

⑴ Punch a punch with a spherical end against a specimen clamped in the cushion die and film to form a dent with high energy density. After focusing the high-power laser beam, the focal spot diameter is very small, so the power density is very high, up to 105 ~ 108w/cm2, which is higher than that of arc welding (5 × 102 ~ 104w/cm2), which is several orders of magnitude higher, and can weld materials with high hardness, high brittleness, high melting point and high strength

⑵. The heat affected zone and deformation zone are small. The heating and cooling speed of laser welding is extremely high, and its crystallization speed is dozens of times higher than that of general fusion welding. The heat affected zone is very small, and the material deformation is small, so there is no need for subsequent process treatment

⑶. Weld combinations of different materials. It can weld dissimilar or identical metal materials with high melting point, high thermal conductivity and great differences in physical properties

⑷. Laser welding system has high flexibility. The welding system combined with cad/cam or robot can form a multifunctional laser processing system, which has fast welding speed, high efficiency and easy automation

before the 1970s, due to the lack of high-power continuous laser devices, the focus of research was on spot welding of small precision parts, or seam welding formed by lapping a single weld. Today, with the improvement of laser power, it is easier to weld steel plates with a thickness of more than ten millimeters

in addition, laser welding is widely used in aerospace devices because of its small thermal effect, good sealing, and suitable for processing in special environments such as vacuum. The high-precision laser welding machine produced by Huagong laser is specially used for welding tantalum capacitor devices for Shenqi launch device and spacecraft internal instruments in a military enterprise in Guizhou. A military factory in Guizhou specially provides military tantalum capacitors and military relays for aerospace. Special alloy housings are used, which need to be sealed and welded in a pure nitrogen environment. For this special application, Huagong laser has developed a vacuum glove box laser welding system, which realizes perfect welding of products

at present, the latest application achievement of laser welding is that the laser welding technology is used to replace the traditional rivets to manufacture the aluminum alloy aircraft fuselage, so as to reduce the weight of the aircraft fuselage by nearly 20% and improve the strength by nearly 20%. Now, German Aerospace Company MBB and Airbus have applied this technology

(II) laser cutting technology and laser drilling technology:

the principle of these two technologies is to focus energy into a small space, so as to obtain a very high irradiation power density (105 ~ 1015w/c m2), and then use this high-density energy for non-contact, high-speed, high-precision processing. Among them, laser cutting technology is a new cutting method that gets rid of the traditional mechanical cutting and heat treatment cutting. It has the characteristics of higher cutting accuracy, lower surface roughness value, more flexible cutting method and higher production efficiency

at present, typical aircraft parts are made of special alloys such as aluminum alloy, titanium alloy and high temperature resistant alloy, which have complex structure and shape and precise forming requirements. The introduction of high-power laser cutting machine processing technology can improve the processing quality, reduce the mold investment cost and shorten the production cycle, especially suitable for the processing of complex parts and components. Last year, contour DM numerical control laser cutting machine manufactured by Huagong laser farilai won the bid in one fell swoop in the laser cutting machine procurement project of a military enterprise in Xi'an, breaking the pattern that imported high-power laser cutting machines monopolize the processing field of special alloys and aircraft engine parts, marking that the processing technology of domestic high-power laser cutting machines has reached the international advanced level

as one of the methods of hole machining on solid materials, laser drilling has become a processing technology with specific applications. These two technologies are mainly used for laser drilling of aeroengines and turbine blades and laser cutting of aeroengines in the aviation field. For example, many international aero-engine enterprises use three-dimensional laser equipment to cut and drill high-temperature alloy materials in the burner section; Laser cutting of aluminum alloy materials or special materials for military and civil aircraft has also been successful, especially in the research on the cracking and remelting layer of titanium alloy laser cutting

in the "Shenzhou VII" spacecraft, because the spacecraft will generate a lot of heat when flying in the atmosphere, many cladding layers are needed in the spacecraft to realize heat insulation. In order to smoothly exhaust the air between the cladding layers in the process of temperature rise, many tiny holes need to be evenly distributed on the upper surface of the cladding layer, The automatic laser cutting machine developed by Huagong laser for this application and combined with its own thin material laser cutting patent has been applied to the cladding cutting of Shenqi

(III) rapid prototyping technology:

rapid prototyping technology is a forming method based on the discrete stacking principle, which is directly driven by the product 3D CAD model data, assembles (stacks) material units and completes any complex 3D entity (without use function). The application of rapid prototyping technology in the aviation field is directly reflected in the direct manufacturing of titanium alloy structural parts for aviation and the rapid surfacing of Aeroengine Parts. For example, in 2001, with the support of the U.S. Department of defense, laser proximity manufacturing technology was transformed from technical research to installed applications, which were applied to f/a-18e/f, F-22, JSF and other advanced fighter aircraft. For another example, the U.S. military uses helicopters in harsh desert environments. Because many impellers with blades on the engine are eroded by sand particles, the flight life of helicopters is sharply reduced. For this reason, the US military has introduced lens technology to repair the damaged parts. It is reported that it costs about US $110000 to repair a helicopter engine by using traditional methods, while it only costs about US $500 to repair it by using laser direct manufacturing technology, and the wear resistance of the repaired part is better than that of the original material. This shows that this technology may produce huge economic benefits

(IV) laser melt coating technology:

laser melt coating technology is a surface modification method that uses high-energy density laser as the heat source to melt a layer of cladding material on the surface of the substrate, so as to realize metallurgical combination with the substrate, and form an alloy layer with completely different composition and properties on the surface of the substrate. This technology integrates rapid prototyping manufacturing technology and laser cladding surface modification technology, and can realize the repair of three-dimensional metal parts without tools and dies. In the aviation field, the price of aero-engine spare parts is very high, so it is more cost-effective to repair parts in many cases, but the quality of repaired parts must meet the safety requirements. For example, when there is damage on the surface of aircraft propeller blades, it must be repaired by some surface treatment techniques. In addition to the high strength and fatigue resistance required by propeller blades, we must also consider the increasingly strong corrosion resistance after surface repair. Laser cladding technology can be well applied to this. In addition, laser cladding technology can also be used in the repair of turbine blades, shell joint parts, valve body parts and other parts

with the implementation of a number of large plans and projects for the imported sensors adopted by the world's famous sensor manufacturer American Quanli sensor, China's aerospace industry has ushered in its own spring, and the laser advanced manufacturing technology, which is at the forefront of the development trend of manufacturing technology, is showing its increasingly important role in this field. We have reason to believe that in the near future, laser manufacturing technology will get greater and more applications in the aerospace field. (end)

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