Study on Single-Point Machining Technology of Supersmooth Surface Using a Flying Tool

目前的超精密车削是基于运动仿形的概念，因此加工精度取决于机床的运动精度。超精密机床的精度差于10 nm，近期很难提高。在此基础上，提出了一种利用飞刀加工超光滑曲面的新技术，即使机床上存在误差运动也能实现超光滑曲面的车削加工。在此过程中，带有蓝宝石芯片的盘状滑块通过流体动力轴承的作用跟随预加工表面。在本研究项目中，对该技术的切割机理进行了研究：(1)将刀具刃口的高度保持在表面粗糙度的峰谷之间，从而通过截断提高表面光洁度；(2)切割深度随工件表面的垂直加速度变化，延时较小，具有改善波形度的可能性。同时，利用两个象限光电池研制了一种新型光学检测系统，用于测量加工过程中工件的轮廓和滑块的姿态。在该系统中，利用三角测量原理测量位移，利用光学杠杆原理测量倾斜角度。通过对角度的积分得到表面轮廓。与其他光学干涉方法的测量数据比较，结果具有较高的重复性和可靠性。

The present ultraprecision turning is based on the concept of motion copying so that the machining accuracies depend on the motion accuracies of a machine tool. The accuracies of a ultraprecision machine tool is worse than 10nm and it is very difficult to improve that in the near future. Then, a new single-point machining technology using a flying tool has been proposed in order to turn a supersmooth surface even if error motions exist on the machine tool. In the process, a discoid slider with a sapphire chip follows the prefinished surface by the action of hydrodynamic bearing. In this research project, the cutting mechanism of the technology was investigated as follows :(1) The height of the cutting edge was kept between the peak and the vally of the surface roughness so that the surface finish was improved due to the truncation.(2) The cutting depth varied following the vertical acceleration of workpiece surface with small delay, which has some possibility of improving the waviness.At the same time, a new optical inspection system has been developed using two quadrant photocells in order to measure the profile of the workpiece on the machine and the posture of the slider in the process. In the system the displacement was measured applying the principle of triangulation and the inclination angle was detected applying the principle of optical lever. The Surface profile was obtained through the integration of the angle. The results had a high repeatability and a high reliability with comparison of the measured data using other optical interferometric method.