Laser-interferometric device for ring gauges calibration

The diameter measurement of the cylinder bores is the specific problem of the length metrology. In practice, this operation is realised using three-pointed bore gauges - inside micrometers. The ring gauges - setting rings are used for testing of the inside micrometers. Such ring gauges are manufactured from the wear resistant steel or zirconium ceramic with diameter tolerance of I mum and shape tolerances according to DIN 2250. Since the setting rings of highest accuracy are the reference standards of 2(nd) order, there is necessary to carry out their precise calibration. This article describes the optical design of the device for the ring gauges calibration.