The inspection of geometrical parameters of through holes with different configurations is one of the urgent tasks in
industry. The majority of the existing noncontact inspection methods doesn't allow measuring the holes of complicated
(noncylindrical) configurations with good performances. Two simple developed methods based on diffractive optical
elements (DOEs) make possible to inspect the through holes (with the diameter from 5 to 100 mm) both cylindrical and
complicated configurations with acceptable lateral and axial (longitudinal) resolution. First method, based on the
scanning of inner hole surface by light ring, takes a mechanical displacement of the inspected article along its axis. The
second holes inspection method uses the DOE as the diffractive focuser, which generates N light rings simultaneously
along the hole axis with ring spacing &Dgr;z. In this case no need for mechanical displacement of inspected articles, output
image contains full measuring information about 3D article hole configuration. We have fabricated some binary DOEs
using circular laser writing system CLWS-300, developed and produced at the TDI SIE SB RAS. The obtained results
have been used under the development of universal automatic inspection system of nuclear reactors fuel assemblies
spacer grids.
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