Development of a CNC lathe with tandem moving table for high speed turning (Evaluation of high-speed motion and effect of vibration transmission suppression)

Abstract

A new CNC lathe with a tandem table unit driven by two linear motors has been developed for machining non-axisymmetric curved surfaces by turning. This lathe, which equips 4 axes (X1 X2, Z and C), enables to realize the NACS-turning (Non-Axisymmetric Curved Surfaces Turning) with high speed machining synchronizing with the spindle rotational position. The key factors for this turning method is not only to realize precise tool tracking ability for the commanded position but also to cancel the inertia force caused by the rapid motion with high acceleration and deceleration. Therefore, the dynamic response of each axis is required so that the curved surfaces is machined accurately with the rapid motion, high acceleration, and jerk. In this study, we introduce a new CNC lathe with 4 axes including a tandem table unit that has achieved the acceleration and the deceleration of over 100m/s2 by the use of the tandem linear motors driving system. Each table is controlled synchronizing to obtain the accurate trajectory on the designed curved surface by canceling the inertia force during machining motion. In this report, the fundamental dynamic performance of the table motion of the CNC lathe are measured and evaluated. The effectiveness of suppression of the vibration transmission to the CNC lathe during the motion control for the curved surfaces is also evaluated.

Keywords

• high speed machining
• nc tandem tables
• linear motor
• inertial force
• nacs-turning