Integrated inspection and process control for machining a circular contour on a two-axis vertical turning lathe

Abstract

This paper examines the integration of readily available commercial hardware into a simple methodology for machine tool performance enhancement through process-intermittent inspection, process stability monitoring, and tool path compensation. Workpiece-specific process-intermittent inspection is performed on-machine and is calibrated using a simple spherical artifact. The developed methodology focuses on integrating the use of readily available commercial hardware. The on-machine probe is used for process-intermittent workpiece inspection and for process monitoring, while the ball bar is used for preliminary assessment of machine tool's ability to compensate for motion and positioning errors. The methodology uses on-machine inspection of initial machining operations to generate compensation trajectories, which are then implemented during the second machining operation. Cutting tests using the developed methodology are performed on an Okuma & Howa V40R two-axis vertical turning centre. The results show that the average absolute deviation of the machined contour of a hemispherical workpiece (90° circular tool path) is reduced to 2.54 µm (0.0001 in) as verified by a coordinate measuring machine.