Abstract
A lathe is one of the most popular model in the machine tool, and it is used everywhere. CNC lathes aim less labor reduction, high efficiency and high accuracy by automatically generating the relative motion between the work piece and cutting tool by the NC program. However, their accuracy had not been valued more than milling machine (machining center). In this report, in order to recognize the motion accuracy of original CNC lathes again, the ball bar circular motion tests were performed and reported. At the same time, the structure of the feed drive system was reviewed in order to understand the test result of the circular test.
