A 6000 groove is drawn in a distance of 1 mm, and the groove shape is uniform, which means that the groove pitch error is less than one thousandth of a hair strand within a 20 km distance. This is the scoring precision achieved by the "large-scale high-precision diffraction grating scriber" developed by the Changchun Institute of Optics, Fine Mechanics and Physics of the Chinese Academy of Sciences.
Into the Changchun Institute of Optics and Mechanics, the scientific team of the project team introduced a silver-gray, nearly opaque "glass window" grating to the reporter. It is the masterpiece of this "king of precision machinery" and is currently the largest in the world. High precision intermediate step grating. To build this "king of precision machinery" is the three-generation development project group of the old and middle-aged grading machine of Changchun Guangji.
Grating is a "chip" for analyzing the spectral information of all things, and it is used throughout the sea, land and air.
How do humans know the world through light? Tang Yuguo, project leader and researcher at Changchun Institute of Optics and Mechanics, said that there are two ways for humans to use the world of light perception: optical imaging and spectral analysis. Optical imaging can see the external information such as the shape and size of the material world; the elements known on the earth and their compounds have their own characteristic spectral lines, and spectral analysis can obtain information on the composition of matter, helping us to see the essence of things. .
But it is not easy to "catch" the spectral information. The light in daily life is a complex light composed of various monochromatic lights such as red, orange, yellow, and green, and monochromatic light can better record the spectral information of the substance. A grating is a very precise optical component. Its magic is that it can resolve and extract monochromatic light from complex light.
In daily life, people rarely see gratings, but in fact, its role is everywhere. "People go to the hospital for blood tests. The principle is to rely on the grating in the spectroscopic instrument to observe whether the components in the blood meet the health standards." The project team member, Changchun Institute of Optics and Mechanics researcher Bayin Heig said, "Simply put it Spectral analysis requires spectroscopic instruments. The role of gratings in spectral analysis is as the core of the chip and the 'brain'.
Similar to the principle of blood tests, analyzing the spectrum of different substances can detect many important information such as pesticide residues, steel quality, and explosive properties. Tang Yuguo said that the value of gratings is not limited to spectrometers, and its application "is used in all walks of life such as agriculture, light, sea, land and air, eating and wearing. It can not only see the sky, but also see the land and see people." In astronomical observation, the composition of the celestial body and its distance from the Earth are obtained by spectral measurement, thus revealing the law of birth and evolution of the universe. In the field of optical communication, the light splitting effect of the grating enables different wavelengths of light to carry information along the optical fiber into thousands of homes. Ten thousand households...
In general, the stronger the performance of the grating, the finer the composition of the material that can be analyzed. The larger the grating area, the higher the etendue and resolution power; the higher the accuracy of the grating, the higher the signal-to-noise ratio. In 2009, the research and development of the grating scribing system started by the Changchun Institute of Optics and Fine Mechanics of the Chinese Academy of Sciences was aimed at the world's leading level from the beginning, and solved the problem of “bigger†and “fine†at the same time.
The "King of Precision Machinery" successfully engraved a large-area step grating of 400 mm × 500 mm, which indicates that China's large-area grating manufacturing technology has reached the international leading position. How strong is this piece of grating? Tang Yuguo said that the most experienced painters can discern subtle changes of more than 1,000 colors, and the grating can theoretically distinguish more than 400 million species, which is the strongest weapon in the world to perceive color.
The grating scriber is the master machine for making gratings. The "bigger" and "fine" gratings are the world's problems.
Armed with dust-proof clothes, and then dusted by the air shower, the reporter was allowed to enter the laboratory. There is a sophisticated environmental protection system that requires a temperature difference of ±0.01 °C within 30 days.
Qi Xiangdong, a member of the project team and a researcher at the Changchun Institute of Optics and Mechanics, participated in the design, development and commissioning of the grating scoring machine, and served as a conductor in the long-term. He said that this instrument is extremely demanding on the environment, and even extremely small changes in temperature, pressure, and air composition may cause huge scratching errors at the nanometer scale.
The demanding requirements for the environment are derived from the high precision of the grating scriber itself. It is made up of thousands of components and components, and almost all key components hit the world's limit. The processing and assembly adjustment accuracy is difficult, and the operation guarantee environment is high, unprecedented.
Screws, worm gears and guide rails are the "three major pieces" of the scoring system. At the time of the project's start, the existing domestic machine tool technology could not meet the accuracy requirements. The research team had to adopt the soil method - hand grinding.
The lead screw is known as the "heart" of the scoring machine, and its accuracy level directly affects the performance of the whole machine. Can not be built in China, can not buy abroad, the retired 80-year-old expert Zhang Tai returned to the office, and personally went to lead the youth team regardless of day and night processing and testing. It took nearly a year to finally grind out the screw. This is also the highest precision and longest trip screw thread in the world.
In the same way, the project team took six months to process the worm gear and eight months to machine the V-shaped guide rail. These key components with sub-micron and nano-scale are all ground by researchers using both hands. In addition, in order to overcome the technical problems of diamond scribing knife and grating coating, the project team members also repeatedly experimented, grinded and adjusted to meet the requirements of the grating scoring machine. "On one occasion, the project team went outside to communicate. When shaking hands, the other party said that your hands are not like scientists, but like workers." Bayin Heig recalled.
At the beginning of the project, the development plan was three and a half years, but because the whole process was much more difficult than expected, it took nearly 8 years to become a “seriously delayed projectâ€. "During the development period, we were under tremendous pressure. Often, we pressed the gourd and scooped it again. It was difficult to overcome a difficult problem, and new problems immediately appeared." Qi Xiangdong said that researchers are constantly looking for the root cause of the problem. Sometimes, even the overthrow of the assumption that took a long time to build up, negating myself to start again. "In the past 8 years, I have felt desperate many times, thinking that it will not go on. When the large grating passed the acceptance, I felt that everything was worth it."
This result makes China no longer subject to people in the field of gratings, and pushes precision machining technology to the forefront of the world.
There are few countries in the world that master the technology of grating development, and large-area high-precision gratings are the focus of competition in science and technology. Prior to this, only the United States was able to produce intermediate ladder gratings of more than 300 mm.
The successful development of large-area and high-precision grating scribers has made the gratings required in China's strategic high-tech fields no longer subject to people, and has also pushed China's precision machining technology to the forefront of the world.
"Our generation of researchers have made this machine, and it is inseparable from the efforts of several generations of Changchun optomechanics. We are only those who pick peaches. Without the accumulation of their predecessors, it is impossible to complete this without the contributions of the youth echelon. The arduous task is the crystallization of the three generations of the old, middle and young." Qi Xiangdong felt.
In 1959, Changchun Institute of Optics and Mechanics independently developed China's first grating scribing machine and the first grating. During the project, Liang Haoming, the leader of China's first generation of grating scoring machine and the founder of mechanical scribing grating, returned to Changchun Institute of Optics and Mechanics and gave guidance on important issues; led the team to manually grind precision parts such as lead screws. Mr. Zhang Tai is also a participant in the development of the first grating scribing machine in China; the retired researcher Hao Dejun participated in the overall structural design of the system.
At present, China's first grating scriber still has no "retirement." More than half a century ago, Liang Haoming and others began the development of grating scribing machines with only a small amount of published literature. Without specially designed computer software, designers draw by hand to draw pictures; without CNC machine tools, researchers rely on both hands to polish parts, and the precision is even higher than today's CNC machine tools.
In the 1980s, Changchun Institute of Optics and Fine Mechanics planned to develop a high-precision large-area grating scribing machine. Due to various restrictions such as funds, the project ran aground. China regretfully missed the opportunity to catch up with the grating manufacturing power, and the manufacture of large gratings became the grating people of China. dream.
“We have confidence and faith to complete the project. Changchun Optical Machinery has decades of technical accumulation. In addition, modern precision instruments have higher processing skills and better technical conditions. The older generation can produce in the age of material shortage. Accurate grating scriber, we have the conditions and responsibility to do a new generation of scribes." Qi Xiangdong said.
After eight years of grinding a sword, the project team developed this large-scale high-precision grating marking system to overcome 18 key technologies and achieved 9 innovative results.
What makes Tang Yuguo happy is that after the experience of the grating scoring machine project, a group of young talents have grown up and the key technologies have been effectively passed down. He also said that the success of the development is not the focus of the scoring machine. The future project team will continue to improve and upgrade its technology from the four aspects of “sense and fast newâ€, so that it can meet the national major scientific research. At the same time of grating demand, it always maintains international leadership.
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