Calibration of the multiangular prism (polygon)

Abstract

Precision polygons (miltianguar prism) are by now considered to be the most accurate relatively widely available mean of angle measurement. Poly-gon/autocollimator measurement system is implemented for various tasks such as accuracy testing and calibration angle measuring instruments, rotary tables etc. Therefore determination of accuracy and calibration of the polygons is an important task analysed and performed at most of the high level metrology laboratory worldwide. There are various methods of calibration of precision polygons de-scribed in the literature; here in this paper we present the comparison test of two calibration methods – “simple” calibration and comparation, with the use of instrumenta-tion available. According to the results the highest accu-racy (standard deviation of 0.151˝ compared to the results of calibration performed at PTB) was reached implement-ing comparation of high accuracy rotary table measure-ments with tested polygon/autocollimator. Other calibra-tion method (“simple” calibration) showed worst accuracy due to the imperfection of measurement environment. The results of the experiment showed that relatively high accu-racy of precision polygon calibration can be reached even with available level of instrumentation, automation and environmental conditions control.