Dynamic length metrology (DLM) for accurate dimensional measurements in a production environment by continuous determination and compensation of thermal expansion effects in turning steel

Abstract

This work concerns the accurate dimensional measurement of metal parts directly in a production environment. Applying an approach with the simultaneous measurement of part dimension and temperature over time (dynamically) followed by modeling of the thermo-mechanical effects, the corrected length at 20 °C and its measurement uncertainty can be predicted. This paper describes a test campaign where the local diameter of a 40 mm cylindrical steel workpiece cooling down from an initial surface temperature after turning of 27 °C to an ambient temperature of 21 °C was predicted after 10 min with a systematic error of 0.5 µm and an expanded uncertainty (k = 2) of 0.9 µm.