Abstract
We have previously developed a path control method with minimum desired point search and implemented it to a linear motor table, and we have experimentally verified the effectiveness of the method. In the present study, the path control method is improved and applied to a numerical control (NC) milling machine to examine the method's practicality. In conventional control methods, path error can be minimized, but the problem of large speed variation along the cutting path remains. Maintaining constant speed in the control of NC milling machines is crucial for making cuts with low surface roughness. Accordingly, the improved path control method is proposed, which considers the velocity of the component in the movement direction, in order to control both the speed and position of the cutting tool of NC milling machines. A commercially available NC milling machine is reconfigured to enable switching between the original NC controller and the proposed controller. Slotting and side milling are performed using the proposed path control method, and the control performance of the system is compared with the performance of independent control along each axis and NC controller. Average path error, speed along the path, and cutting surface roughness are examined, and the effectiveness of the proposed path control method is verified.
