Current Situation and Development of Optical Parts Processin

Writer： admin Time：2020-01-15 16:53 Browse：℃

 
Ⅰ、summarize
The demand for optical components has become increasingly widespread with the development of modern science and technology, from cell phones that we have each had since childhood to televisions and computers in our daily life, to military and aerospace in the field of national defense.
More and more precision instruments have applied the new technology of combining optics, mechanics and electronics, which has pushed them to meet the increasingly strict requirements of multifunction, high performance and low cost, and has promoted the development of traditional optical parts production technology and the change of processing technology. This change has promoted the development of optical mechanic technology in two different directions.
First, it will develop towards small, light and cheap high-efficiency processing. With the rapid development of optical plastics and glass die casting technology, the cost of aspheric lens has been greatly reduced and the supply of aspheric lens has been greatly increased. More and more optical systems have been adopted. For example, a very thin zoom lens has been widely used in mobile phones. It is precisely because the application of these small, light and cheap optical parts in various fields continues to expand that the rapid development of optical efficient processing technology is driven.
Second, it is developing towards ultra-precision machining. The technological progress in cutting-edge science and technology, especially in the national defense industry, has put forward new requirements for ultra-precision optical parts. For example, manned space flight, optical systems of laser weapons, optical fiber communication components and micro optical components in optical integrated circuits are all ultra-precision optical components. The machining accuracy of these optical parts has even reached nanometer level. The processing of these parts cannot adopt traditional methods, and can only be realized through ultra-precision processing technology.
The traditional processing method of optical parts has a history of more than 100 years and can be understood as "a handful of sand and a handful of water". However, the new processing method of optical parts began in the 1970s. Military optical systems were expanded from white light to infrared and laser systems, which also required optical parts to have good imaging quality, small volume, light weight and simple structure. With the large-scale technological revolution and innovation in the optical processing industry, new processing methods for optical parts have emerged. At present, the commonly used optical parts processing technologies mainly include: numerical control single-point diamond processing technology, numerical control grinding and polishing technology, optical lens molding technology, optical plastics molding technology, magnetorheological polishing technology, electroforming molding technology and traditional grinding and polishing technology.
Ⅱ、the basic principle of ultra-precision machining technology
1, numerical control single point diamond processing technology
Numerical control single point diamond machining technology is a kind of aspheric optical parts machining technology. It uses a natural single crystal diamond cutter on an ultra-precision numerical control lathe to machine aspheric optical parts by single-point turning with the diamond cutter under the precise control of a specific processing environment. The technology is mainly used for small and medium-sized infrared crystals and optical parts of metal materials.
2, CNC grinding and polishing technology
The numerical control grinding and polishing technology is an optical part manufacturing technology in which the surface of a workpiece is ground into a required surface shape by a numerical control precision machine tool, and then polished by a flexible polishing die to enable the workpiece to meet the technical requirements. The principle of this technology is closest to the classical optical processing technology. It mainly realizes the precision processing of optical parts through the digital precision control of machine tools.
3, optical lens molding technology
The molding technology of optical lens is to put softened glass into a high-precision mold and directly mold optical parts to meet the use requirements under the conditions of heating, pressurizing and oxygen-free. It can be said that the popularization and application of optical lens molding technology is a major revolution in the processing technology of optical glass parts. This technology is of epoch-making significance to reduce the cost and increase the output of aspheric glass parts.
III. Application Scope of Ultra-precision Machining Technology for Optical Parts
1. Numerical control single-point diamond processing technology
At present, the materials that can meet the quality requirements of optical surface can be directly processed by diamond turning technology, mainly non-ferrous metals, germanium, plastics and infrared optical crystals. However, the processing of glass cannot meet the quality requirements of optical surface, and continuous grinding, polishing and correction are needed. Another main use of NC single-point diamond processing technology is to process various precision dies required for compression molding.
2. CNC grinding and polishing technology
The main processing material of CNC grinding and polishing technology is glass, which is making up for the defect that CNC single-point diamond processing technology cannot directly process finished optical glass parts. The technology is mainly used for processing spherical and aspheric optical parts, and is the main technology replacing the traditional classical optical glass processing method. It has the advantages of high precision, high processing efficiency and the like. At present, this technology has a long history of development in the market and mature equipment is relatively comprehensive. For example, Germany Satisloh Company, Optotech Company and Schneider Company have introduced different types of milling and polishing machine tools. China has also carried out a large number of research on numerical control technology.
Computer numerical control grinding and polishing technology has not only made great progress in the automation and machining accuracy of numerical control equipment, but also greatly promoted the development of optical aspheric surface machining technology through the research on various polishing methods and principles.
3, optical lens molding technology
At present, optical lens molding technology has been used to mass produce precision spherical and aspheric lenses. Not only can the commonly used medium-caliber lens be manufactured, but also the microlens array extending to 100 microns and the larger-caliber lens of 50 millimeters can be manufactured, not only the spherical and aspheric optical parts in military and civil optical instruments, but also the aspheric lens for optical fiber couplers for optical communication and credit.
At present, this advanced manufacturing technology of glass optical parts is still in the hands of a few foreign companies such as Corning, Rochester Precision Optics(RPO), Maxell, Japan's OHARA, HOYA, Olympus, Panasonic, Germany's Chase, Britain's Bluebell Industries and Holland's Philip.
Ⅳ、optical parts ultra-precision machining technology progress at home and abroad
1. Present Situation of Ultra-precision Machining Technology for Aspheric Parts Abroad
In the world, optical processing has developed to the fifth generation of numerical control processing technology, achieving high precision, high speed, high efficiency and specialization, and has been able to complete the processing of high precision aspheric parts, of which Germany's optical processing technology is more prominent.
Their numerical control machining technology not only covers milling, grinding, forming and polishing technologies of various surface types from plane, prism, spherical surface to aspheric surface, as well as matching high-precision detection technologies, and the machining size and detection range are from Φ 1 to 800 mm. It is especially prominent in the processing of aspheric surfaces, and the processing of high-precision aspheric surfaces can be easily completed by advanced craftsmanship. Some aspheric surface processing methods use grinding wheel outer edge point contact milling, and some use elastic film polishing and then small grinding head to correct polishing. Workpiece clamping methods include hydraulic pressure, vacuum adsorption, etc.
2. Present Situation of Ultra-precision Machining Technology for Aspheric Parts in China
The research on ultra-precision machining technology in China began in the early 1980s, and there is a gap of more than 20 years between China and foreign countries. The processing technology of optical parts in China's military photoelectric enterprises has developed over the years, and the aspheric surface numerical control processing technology has also developed greatly in recent years. In particular, the aerospace system should introduce some advanced technologies and equipment, and the technical level of some enterprises has been greatly improved. However, the optical processing of photoelectric enterprises in the weapon industry generally adopts the traditional technology. Most aspheric surface processing relies on manual grinding, which is extremely low in efficiency and prone to errors and poor in reliability. The compression molding of optical glass lens only stays at the blank stage. With the increasing demand for large-caliber and high-precision aspheric mirrors in modern weaponry, the improvement of aspheric surface processing technology is imminent. However, due to the high price of imported aspheric surface numerical control processing equipment, most enterprises are equipped with only a small amount of equipment, which can only solve the aspheric surface processing of existing high-end products. It is difficult to form batches and propose new processes on this basis.
V、concluding remarks
At present, foreign developed countries have developed new optical systems for more than 30 years. New optical systems, especially high-order aspheric optical systems, have been developed and utilized considerably. There is still a considerable gap, even a gap, in this field. This situation has seriously hindered the development of high-performance optical systems in our country and affected the equipment level of our army. It is of great significance to carry out research on application basis, key technologies, systems and engineering technologies. With the development of ultra-precision machining technology, the design and manufacture of modern optical systems have achieved revolutionary development, changing the situation that conceptual design of optical systems has stagnated for hundreds of years. It is of great significance to solve the bottleneck technology in the manufacturing of modern optical systems in China, especially in the processing of high-resolution, large-aperture and high-order aspheric optical systems, to reach and break through the actual level of high-resolution and large-aperture optical systems in the world at present, and to realize a new step in China's advanced optical manufacturing technology.
 
References
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[2] Shu Chaolian editor. Modern optical manufacturing technology. Beijing: National Defense Industry Press, 2008.8
 [3] Zhang Zengyang, editor-in-chief. Collection of Modern Optical Manufacturing Technology. Beijing: Optical Technology Magazine of North Optoelectronic Technology Co., Ltd. August 2002
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Beijing: china optics and optoelectronics, April 2010 (Author: China Wuzhou Engineering Design Group Co., Ltd.)
Source: Research on Modern State-owned Enterprises, Author's Brief Introduction: Wang Jiangang (1978 ~), Male, Graduated from changchun university of science and technology, Senior Engineer, Research Direction: Engineering Consultation and Design for Optical and Electronic Projects.