A was twist twist, the surface is very rough engine blades, is a CNC machine tools continue to be polished polished, saw the operation of the CNC machine, a short while later, the belt will accurately polished the entire blade smooth, Even the dead did not fall.
Gas turbine compressor blade grinding
Commercial high-pressure compressor blades R1.5 root fillet grinding effect
Do not underestimate this process, smooth blades, will play a crucial role in the performance of the aero-engine.
Do not underestimate this machine, which broke the monopoly of foreign technology for China's nuclear power, gas turbines and aircraft engine manufacturing provides advanced technology means.
'Blade complex curved surface parts are the key components of steam turbine, gas turbine, aeroengine and other power plant. Its geometric precision and surface quality directly affect the working efficiency of energy power equipment. The consistency of its quality directly affects the safe operation of power machinery. Liu Hong for general manager of Hong Technology Control Equipment Co., Ltd. told science and technology daily reporter.
It is understood that by the Beijing Science and Technology Co., Ltd. Watson Hong Kong and other units for the development and research of 'complex surface profile precision machining six-coordinate CNC abrasive belt key technology research and application' project, through research and development, developed its own intellectual property rights Blade six coordinate linkage CNC belt grinder and programming system to solve the blade complex surface grinding finishing difficult technical problems, breaking the foreign monopoly, the results used in China's nuclear steam turbine blade manufacturing and new aero-engine blade manufacturing, a high-quality The necessary means for the manufacture of leaves In the 2016 Beijing Science and Technology Award, the project won the first prize.
Manual polishing has become the bottleneck of development bottlenecks
Equipment manufacturing industry is the cornerstone of a country building, with turbine power plant manufacturing technology is even more a sign of a powerful country, while the turbine power plant is the core of the blade.
'Work status of the blade surface finish as high as possible, the surface quality, consistency affects the energy conversion efficiency of the equipment.' Liu Shusheng told reporters.
It is reported that the general for the processing of nuclear power, thermal power plant steam turbine blade surface machining multi-axis CNC machine tool is the turbine equipment manufacturing high-end key equipment.From the morphological point of view is a complex thin-walled parts, the surface is free space Surface, large changes in curvature, prone to deformation after CNC milling, resulting in the surface can not be used conventional finishing.
With the increasing power of energy and power plant, in order to obtain better aerodynamic effect and maximize the power per unit volume, the blade-type surface is more curved, twisted, swept and the surface is more complicated.
'China generally use manual polishing method of processing large blades, poor leaf accuracy, low processing efficiency, labor conditions are very bad.' 'Liu Shusheng told reporters that a large number of hand-polished dust, seriously affecting the health of operators.
Liu Shusheng company is located in Beijing Yizhuang, the reporter saw a hand-polished leaves in the workshop, the surface has obvious signs of manual grinding, sharp edge sharp, the groove has raised points, burrs and polished after the groove convex point , Glitches, sharp edges, etc. are ground to a smooth state, and the surface texture is uniform.
It is understood that some complex profiles of the leaves, if not smooth enough, do not meet the aerodynamic, in addition to consuming a lot of human resources, but also easily lead to product quality instability, and even affect the performance and life of the engine machine using the traditional manual polishing method , Can no longer meet the requirements of advanced blade manufacturing quality.
'Manual grinding and polishing will destroy the preface with a precision five-axis milling of the blade out of the precise profile.' Liu Shusheng said.
The mismatch between advanced five-axis milling equipment and manual grinding and polishing has become a bottleneck restricting the rapid development of the blade industry.This is a very important issue in the manufacturing process of large blades represented by nuclear power blades and small blades represented by aero-engine blades In particular, reflected.
For large blades represented by nuclear steam turbine blades, the volume is huge (the final blade length of CAP1400 PWR nuclear power unit is more than 2 meters in length and weighs more than 280 kg), the profile is complex and the precision is high, and the manual grinding Polishing more and more difficult, inefficient, difficult to ensure the quality of the processing, thus affecting the flow through, affecting the thermal efficiency; In addition, manual grinding and polishing blade consistency is poor, thus affecting the dynamic balance, affecting the safe operation of the unit.
As for the blade represented by aeroengine blade, it becomes the other extreme. The length of the blade is less than 100mm. The bending, twisting and sweeping of the profile are only 0.1-0.2mm (1-2 hundred dollar banknotes) Thickness), integrated contour error<0.05mm, 手工磨削抛光很容易造成叶片烧伤和轮廓破坏, 型面精度根本不能保证. 发动机叶片型面制造质量正是影响我国发动机制造水平, 进而影响各类飞机性能的关键因素.
Domestic machine to achieve 'soft to just'
To change the drawbacks of manual polishing can only be polished by the machine, but this CNC belt grinding machine is monopolized by foreign countries, only Germany and several other countries have the technology.
In 2008, Liu Shusheng and his R & D team, the face of the imported from Germany, the only one blade surface grinding finishing equipment, is to follow or imitation? But that is not what we want .Liu Shusheng said they give Set an approximate impossible task, that is, research and development of six coordinates linked CNC grinding machine, in order to solve the blade profile finishing problems.
This is a problem that the Germans did not solve. 'In the past that the 5 axis can be, but the actual processing found that some pits can not wear, you must use 6-axis.'
Seemingly more than one axis, but more out of the difficulty of research and development is several times the increase in the exact position with the right amount of material removal, which is the same with all the principles of machining, but whether the machine tool trajectory and Grinding pressure in the precise timing and space, is the biggest challenge.
CNC machine tools are known as the "brain" of the manufacturing industry. With the development and application of computer technology, information technology and automation technology, databases, computers and artificial intelligence are used to evaluate, predict, simulate, optimize and control the grinding process. , Automation and artificial intelligence technology to improve wheel grinding, belt grinding process, the grinding process can be controlled, stable, environmentally friendly and more suitable for high-volume production.
To Liu Shusheng, control of automated processes was a stumbling block. "The hardest part was programming, when there was no such specialized software in China," said Liu Shusheng.
Finally, Liu Shu-sheng combined with Huazhong Numerical Control Co., Ltd., put forward the programming algorithm of double vector control and independently researched and developed the six-coordinate NC abrasive belt grinding process programming software. The software has the advantages of six coordinates linkage trajectory smoothing, processing parameter optimization and simulation, Post processing and other functions to achieve automatic programming and automatic processing. And independent research and development of six-coordinate CNC abrasive belt grinding dedicated CNC system to achieve a three-turn, three-axis six-axis CNC interpolation control to meet the complex Blade multi-axis linkage control requirements.
With the development of new materials and new structure of the leaves continue to appear, leaf-shaped curve is also more and more complex, to blade polishing technology has brought greater challenges .Special form of polishing methods have been unable to solve all the blade polishing. Structure, different materials, leaves, need to use different methods of polishing, processing technology more and more complex.
At the same time, the polishing of each part requires the movement of the machine tool, the specification parameters are very different, it is difficult to realize the polishing on different parts of the same machine on the same machine tool.Therefore, the multi-station and multi-processing method parallel process strategy is more suitable for the blade All the bits of polishing.
In response, the project team creatively put forward a hollow C-axis BC double-head structure with built-in belt unit. Developed the first public display of high-dynamic performance of a nine-axis six-axis linked CNC belt grinding machine, achieved nuclear blade Complicated surfaces efficient, high-quality six-coordinate linkage grinding finishing, in the international are original and advanced.
'In the past, the blades were hard-to-touch, but now the blades are all thin-walled parts with curved surfaces. Not only are we going to control the intensity and speed accurately, but we are uncertain.' "Liu Shu-sheng said," Our machine tool is just soft. "
The project team put forward a new type of structure of 6-coordinate CNC belt grinding machine with multi-belt arrangement horizontally to realize micro-contact force control grinding to meet the requirements of fine grinding and exhausting of 0.1-0.2mm thin inlet and exhaust of aeroengine blades and realized Including the blade body surface, into the exhaust side, root fillet, damping transition zone, including the blade integrated grinding finishing.
The six-axis NC Belt Grinder finally developed by the project team can grind and polish the edges of curved and twisted blades that have only one hundred-dollar banknote thickness, with the error no more than one-tenth of its thickness, exceeding the current state of the art .
Polished polished into a big market
'Did not expect polishing can be made into a big market.' With independent intellectual property rights of six-coordinate CNC belt grinding machine put into production, in short supply, which makes Liu Shusheng very much.
Nowadays, our company independently developed the six-coordinate blade-type CNC belt grinding machine, which is widely used in the north and south of the Yangtze River. It is applied in the manufacture of blades for nuclear power turbine units and in the manufacture of new aero-engine blades, and becomes the necessary means for the manufacture of high-quality blades.
It is understood that, at present, the results applied to the East Turbine Co., Ltd. large blade finishing polishing production line and Wuxi Turbine Blade Co., Ltd., the cumulative production of large-scale leaves more than 50,000 pieces worth over 1 billion yuan.
After the actual use of Dongfeng Motor Co., Ltd., it was found that the use of CNC machine tools and numerical control systems was stable and reliable, and the quality of machined blades was a qualitative leap compared with the manual polishing in the past. The consistency of blades produced by the new equipment was very good. Case, high-speed dynamic balancing effect has been superior to the rotor made abroad.
Just like a car, the blades of nuclear power have to be balanced after installation, usually for several hours, but in the installation of the last stage blades of the CAP1400 PWR nuclear power unit in China, it is found that almost no balancing needs to be done. Alston foreign companies do not believe the people, the results found that, in the past, manual grinding blades often have a deviation of 500 grams, and now only 30 grams.
In addition, the results are also applied to the production of a new type of engine fan blade manufactured by Xi'an Aero Engine Co., Ltd. The project achievements are the development of a new type of aeroengine developed by Liming Aeroengine Group and China, the joint venture of AVIC Hui Yang Propeller Co., Ltd. New composite air propeller development, Changhe Aircraft Industry Co., Ltd. new helicopter paddle arm manufacturing provides advanced manufacturing process support.
'With the progress of smart manufacturing, 3D printing and casting technology, we are now developing a new CNC machine tool that will continue to occupy the high ground,' said Liu Shusheng confidently.