Parallelism error measurement for the spindle axis of machine tools by two circular tests with different tool lengths

Abstract

In this study, parallelism errors between the spindle axis and the linear axis of machine tools were measured using a double ball-bar. Specifically, two circular tests were performed to measure the parallelism errors using tool balls with different tool lengths and a workpiece ball fixed to a workpiece table. Parallelism errors were calculated by analyzing, simultaneously, the measured double ball-bar (DBB) data from the circular tests. The proposed method provides accurate measurements due to a large offset between the circular tests within the working space of machine tools. Additionally, the approach only requires a DBB and adjustment/extension fixtures; thus, it simplifies measurements and is cost-effective.