The researches of long linear scale comparator and its environmental temperatures gradient

Abstract

During calibration of linear scales of a few meters in length thermal deformations of the calibrator and the scale being calibrated are the main components of calibration error. The magnitude of the deformations depends not solely on the scale's and calibrator's temperature deviations from the standard temperature but also depends on the spatial temperature gradient and the time-dependent gradient. Despite the fact that calibrators operate in thermally insulated thermo-constant laboratories wherein temperature changes are strictly regulated, however, under the effect of external and internal temperature interference the above-mentioned temperature gradients acquiring essential values have to be determined and estimated. This study presents the methods, applied equipment and results of the experimental investigations into spatial temperature gradients and time-dependent gradients. Dependence of temperature gradients of a long linear scale and calibrator on the variation of ambient temperature and calibrator's heat sources has been analyzed. Suggestions concerning evaluation of those temperature gradients and reduction of their influence on the uncertainty in scale calibration are made.