SelfA-inclinometer: A novel device for evaluating the accuracy of tilting rotary tables in five-axis machine tools

In this study, we developed a compact, high-precision angle measuring device called the “SelfA-inclinometer”. The purpose of the SelfA-inclinometer is to enhance the performance of a tilting rotary table, a crucial component of five-axis machine tools responsible for positioning the tilt and rotation axes. This device measures the tilt angle of the working surface of the table, where a workpiece is mounted, as it rotates around the tilt axis. The measurements are highly accurate, providing indicators for improving design, machining, and assembly accuracy. The measuring device comprises a compact self-calibrating rotary encoder (the SelfA), a rotating device, and a precision level. It mounts directly onto the surface to be measured and can measure a wide 360° range with precision on the order of an arc-second (1 arc-second:″ being 1/3600th of a degree). Comparing it with a national standard angle calibration system as a higher-level device revealed a measurement accuracy of ±2 arc-sec or better. Simultaneous measurements were conducted to compare the results with those obtained from a conventional measuring device like a rotary encoder, assessing the validity and superiority of the measurement.