Advanced large size measures a technology

-- without slideway laser interferometer as aerospace, heavy machinery, generate electricity the development of industry of equipment, shipping, the demand that gauges to large size is higher and higher. The large component that a few nicety cooperate, dimension achieves ten meters even a few meters, precision asks to achieve IT7 above. How measuring these is the technical difficult problem that puzzles metric worker all the time since component is long-term. The measurement that applies actually at present the method still measures a tool to give priority to with the tradition such as measuring staff of outside callipers, internal diameter, cannot satisfy requirement far. Tsinghua university ever was developed give a very good alignment method, be united in wedlock with laser interferometer, use at measuring large size to be able to achieve very tall precision, but this method must use high accuracy oriented slideway, restricted the use in spot of production, installation. Accordingly, development high accuracy, without slideway large size measures a technology, it is a of domain of length gauge quantity main task all the time. The rapid development of laser technology is measured for large size nicety developed brand-new field. Come nearly 20 years, appeared a variety of notting have measurement technique of slideway large size, among them, be paid close attention to extensively having slideway laser interferometer is a development is very rapid in recent years kind of advanced measurement technique. Decimal coincidence method is the foundation that does not have slideway laser interferometer. It is one kind is measured with data processing method, commonly used in gauge block calibrating. Common ground says, a few when this kind of measurement technique resembles using different length " rule " go measuring same an object, want to get the odd amount in addition to the round number of each measured value only, can derive the actual length of the object, it does not care metrical actual process. Laser interferometer is primary unit of measurement with wavelengh, the development of much wavelengh laser, it is to realize different length " rule " foundation. Laser can output the laser of a variety of wavelengh steadily, benefit takes wave skill with optics, can grow these single wave synthesis to be close of a group of wavelengh, interval even " synthetic wavelengh catenary " . "Synthetic wavelengh catenary " it is structure of shape of a tower, cat head is highest wave of one class synthesis, its wavelengh is the longest, tower bottom is odd wavelengh. When measuring, interferometer works with the laser of different wavelengh, from the superlative degree (most long wave) begin, chase class to drop, till Chan Bo is long. The measurement of laser interferometer is a group of the rest below all sorts of wavelengh interference as a result phasic, can push with this derive always measure length, as a result of every time measured value is odd and phasic, with measure a process to have nothing to do, because this does not need oriented slideway. The choice is right " synthetic wavelengh catenary " it is the key that does not have slideway laser interferometer. The long wave interferes the uniqueness that assured measured value, and measure precision to depend on shortwave interference. Measure a process to simplify, still have a kind of method that uses wave of a synthesis only, if use the synthetic wave of hundreds of millimeter, have the aid of at common measure a tool (like tape measure) measure piece roughly synthetic wave periodicity, odd and phasic measure by interferometer piece, this kind of method needs to measure only can finish, construction of system is very succinct also, but the wavelengh that uses as a result of place is longer, measuring precision to go up inevitable somewhat loss. Each country scholar had a large number of research to having technology of slideway laser interferometer, development developed all sorts of laser interferometer, induce as follows: (1) laser of CO2 of CO2 laser interferometer is a kind of illuminant that suits to be measured without slideway laser very much, it is in 10.

Wave band of 6 μ M has substantial spectral line, the wavelengh difference of photograph adjacent spectral line distributings evener also, form " synthetic wavelengh catenary " wavelengh but from 10.

6 μ M arrives 25m, accordingly, CO2 laser interferometer is the research key that does not have slideway laser interferometer all the time. Begin from 1979, by dc interference system arrives multiform smooth heterodyne system, all previous classics improves CO2 laser interferometer for many times, among them a kind of typical program is to go up the heterodyne interferometer that 90 time Australia develops the century, it grows control through the antrum of laser, output 6 kinds of wavelengh orderly, with acousto-optic the 0 class diffraction of modulator serves as Ben Zhenguang, make heterodyne system, measure precision to be able to amount to 4 × 10-8. (2) laser of Ne-Xe of Ne-Xe laser interferometer can be outputted 3.

53 μ M and 3.

37 μ M two wavelengh, synthetic wavelengh is 84.

2 μ M. From " synthetic wavelengh catenary " angle consideration, wavelengh is too short the uniqueness that assures to measure an outcome hard, for this, 3 what the system joined He-Ne laser.

Spectral line of 39 μ M, will " synthetic wavelengh catenary " outspread to 464 μ M. The biggest advantage of Ne-Xe laser interferometer is a structure simple, measure precision to be able to be amounted to 1.

8 × 10-7. (3) the interferometer of laser of fore-and-aft Zeeman He-Ne that academy of metric science of China of He-Ne laser interferometer develops, the interferometer of double frequency laser that develops with Chengdu tool institute is different, its are firm frequency dot is chosen between two laser gain trace, the left, dextral polarized light that produces to be 1080MHz to frequency difference (these two polarized light are not on same gain trace) , synthetic wavelengh is 278mm. The rest that uses grating to measure interference is phasic. The system measures length to be able to amount to 100m, measure precision to be ± (40+1.

5 × 10-6) . He-Ne laser is in 3.

Spectral line of place of 39 μ M is substantial, but among them 3.

The initiative radiate coefficient of spectral line of 3922 μ M is a lot of bigger than other spectral line, restrained other spectral line blast off. Tsinghua university uses methane to be in 3.

One near 3922 μ M draws spectral line, restrained He-Ne laser the intensity of this spectral line, successful development went 3.

Shuang Bo of wave band of 39 μ M grows laser interferometer, its " synthetic wavelengh catenary " from 3.

39 μ M arrives 1m, single wave stability is 1 × 10-8. (4) change wavelengh laser interferometer changes wavelengh laser interferometer uses two laser, use syntonic antrum to grow the concern with output frequency, form " stepless " wavelengh series, below perfect environment, the measurement of 13m length limits precision is 70 μ M. (5) interferometer of laser of semiconductor of linear frequency modulation in recent years, the development of technology of frequency modulation of semiconductor laser linear, provided an ideal light source to do not have slideway laser interferometer, become the heat that interferes technical research without slideway laser. 1995, germany was used outside antrum is adjustable laser of humorous type semiconductor, the antrum outside its by holographic grating composition, undertake through changing the point of view of grating frequency chooses, length of be concerned with can amount to 100m, the resolution of 40m length limits can amount to 40 μ M. The development that does not have technology of slideway laser interferometer is only history of more than 20 years, because it is measured in large size in have irreplaceable value, because of pour into of scholar of this each country a large number of energy undertake study to develop, at present this technology is moved toward stage by stage practical change level. As the development of science and technology, believe to be in before long in the future, be sure to become large size to measure one of the domain gorgeous strange flower without technology of slideway laser interferometer. CNC Milling