Accuracy enhancement of a small overhung boring bar servo system by real-time error compensation

This paper is concerned with the work involved in reducing the machining errors of a small overhung boring bar by real-time error compensation. A boring bar developed is made with a pair of concentric bars with an outer diameter of 14 mm and length of 140 mm, representing an overhang ratio of 10:1. A piezoelectric (PZT) actuator was incorporated in the boring bar servo to achieve on-line compensation. Results of cutting tests show that improvement of 40% in the roundness errors can be achieved through on-line compensation of machining errors in precision boring of holes with high aspect ratios.