Micro-longhole measuring method based on fiber grating

Abstract

The invention discloses a micro-longhole measuring method based on a fiber grating, relating to the field of size measurement into a micro inner cavity. The method mainly reflects the contact condition between a wall-touch spherule and the inner wall of a millipore to be measured through the drift value of the central wavelength of a fiber grating reflectance spectrum and realizes the three-dimensional aperture measurement of the millipore to be measured by the aid of a control circuit and a three-coordinate measuring engine. The micro-longhole measuring method based on the fiber grating, which is provided by the invention, has the advantages of low loss, good spectrum characteristics, high accuracy and good repetitiveness without null drift, expands the measurement range, converts contact conditions in space into the change of an optical spectrum, overcomes the limitation caused by diffraction loss in measuring the millipore to be measured by using a traditional CCD (Charge-Coupled Device) spot displacement method, avoids the influence of the conditions, such as the power fluctuation of a light source, the microbending effect of fiber, the coupling loss, and the like, avoids causing loss to the micro hole and prolongs the service life of an optical probe.

Description

technical field [0001] The invention relates to the field of dimension measurement that can go deep into a tiny inner cavity, in particular to a method for measuring a micro deep hole based on an optical fiber grating. Background technique [0002] With the rapid development of machinery, aerospace industry and cutting-edge industry, there are more and more small-sized parts, how to realize the precise measurement of micro-holes and micro-deep holes has become the key to restricting the improvement of aerospace and automotive device performance indicators. Explore an actionable measurement method. [0003] At present, nanometer-level resolution has been achieved in the measurement of external dimensions, but the measurement level of internal dimensions is relatively backward. The development of precision micro-inner dimension measurement technology is limited by the existing technology level. Scholars at home and abroad have done a lot of research on this. The earliest ap...

AI Technical Summary

Problems solved by technology

If the standard ring is used to calibrate, the accuracy of this measurement method will be higher, but there are still problems in this method: when measuring small holes, the bending deformation of the dry measuring rod will cause a large measurement error, and the force measurement Instability will increase this error

However, due to the diffraction loss caused by the divergence of the beam emitted from the end of the outgoing fiber, the captured spot image signal becomes weaker, which limits the measurement capability of ultra-deep holes

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