Advanced screw thread metrology using an areal measuring strategy and a holistic evaluation method

Abstract

With respect to current manufacturing tolerances, the inspection of screw threads in the field of precision engineering requires measurement uncertainties that cannot be achieved with the standardized measuring procedure in the current EURAMET cg-10 calibration guide. Because the conventional measuring strategy and evaluation method for calibrating screw threads refers only to specific lines along two axial sections, the complexity of the 3D workpiece is not taken into account. The manufacturing industry requires a paradigm shift from line-oriented to areal-oriented measuring strategies. This article presents a holistic approach that starts with the parameterization of complex screw thread geometry, continues with a concept for an areal measuring strategy and ends with the 3D evaluation of the gathered point cloud and the determination of the measurement uncertainty using numerical simulation.