The development of ultra-precision machining has gone through the following three stages.
(1) The technology pioneering period from the 1950s to the 1980s. In the late 1950s, due to the development of cutting-edge technologies such as aerospace and national defense, the United States took the lead in developing ultra-precision machining technology and developed the ultra-precision cutting of diamond tools--Single point diamond tuming (SPDT) technology. Also known as "micro-inch technology", it is used to process laser nuclear fusion mirrors, tactical missiles and spherical and aspherical large parts for manned spacecraft. Since 1966, the United States' UnionCarbide company, the Dutch company Philips and the United States LawrenceLivemore Laboratories have launched
Their own ultra-precision diamond lathes, but their application is limited to the experimental research of a few large companies and research units, and mainly for the processing of products for national defense or scientific research purposes. During this period, the diamond lathe was mainly used for the processing of soft metals such as copper and aluminum, and it was also possible to process workpieces with complicated shapes, but only for axially symmetric workpieces such as aspherical mirrors.
(2) The early 1980s and 1990s were the beginnings of private industrial applications. In the 1980s, the US government promoted the commercialization of ultra-precision processing equipment by several private companies, Moore Special Tool and Pneumo Precision, and several Japanese companies such as Toshiba and Hitachi and Cmfield University in Europe also launched products. The equipment began to be manufactured for general folk industrial optical component goods. However, the ultra-precision processing equipment at this time is still noble and rare, and is mainly ordered in the form of a dedicated machine. During this period, in addition to diamond lathes that process soft metals, ultra-precision diamond grinding that can process hard metals and hard and brittle materials has also been developed. This technology features the use of a high-rigidity mechanism for ductile grinding of brittle materials with minimal depth of cut, resulting in nano-scale surface roughness for hard metals and brittle materials. Of course, its processing efficiency and complexity of the mechanism cannot be compared to diamond lathes. In the late 1980s, the United States invested a large amount of money and a large amount of manpower through the "Laser Nuclear Fusion Project" of the Ministry of Energy and the "Advanced Manufacturing Technology Development Plan" of the Army, Navy and Air Force. Micro-inch ultra-precision machining of large parts. The Large Optics Diamond Turning Machine (LODTM) developed by LLNL National Laboratory in the United States has become a classic in the history of ultra-precision machining. This is a vertical lathe with a maximum machining diameter of 1.625m. The positioning accuracy can reach 28nm. With the online error compensation capability, the machining can be realized with a length of more than 1m and a straightness error of only 25nm.
(3) The mature period of private industrial application since the 1990s. Since 1990, the demand for ultra-precision processing machines has increased dramatically due to the booming industries such as automotive, energy, medical equipment, information, optoelectronics and communications. Applications in the industry include aspherical optical lenses, Fresnel lenses, and ultra-precision molds. , disk drive heads, disk substrate processing, semiconductor wafer cutting, etc. During this period, related technologies of ultra-precision processing equipment, such as controllers, laser interferometers, air bearing precision spindles, air bearing guides, hydraulic bearing guides, and friction-driven feed shafts, have also matured, and ultra-precision machining equipment has become Production machinery and equipment commonly seen in the industry, many companies, even small companies have also introduced mass production equipment. In addition, the precision of the equipment is gradually approaching the nanometer level, the processing stroke becomes larger, and the processing application is gradually widened. In addition to the diamond lathe and ultra-precision grinding, ultra-precision five-axis milling and flying cutting technology has also been developed, and Processing non-axisymmetric aspherical optical lenses.