The Accuracy of Machine Tool Motion at Nanometer Level and Its Transfer Fidelity to Machined Surface

为了改进机床零件运动精度的测量方法，分析机床运动对加工表面轮廓的传递保真度，在分析三点法的基础上，提出了一种新的评定空气主轴转子径向跳动的方法。该方法不需要使用传统的参考球，就能获得转子的真实跳动信息。借助最新研制的亚纳米分辨率、工作范围约30 m的反射式光电位移传感器<mu>，利用该方法对空气主轴的跳动进行了评估。在此基础上，提出了以激光束为直线度基准，评价机床元件直线运动精度的方法 关于我们 纳米分辨率。该方法的原理是高灵敏度地检测固定在运动物体上的四元光电二极管的中心位移，并作为激光束的目标。应用该方法对空气滑道直线运动精度和专门设计的弹性铰链在强迫变形下的直线运动精度进行了测量和分析。成功地测量了空气滑道直线运动的精度为0.1米的量级<mu>。在小于100 m的短行程内<mu>，测得弹性铰链的运动误差小于1 nm。采用上述机床元件进行了一系列切削实验，并对表面轮廓进行了分析。用金刚石工具车削黄铜时，观察到在特定晶粒中表面的形状精度小于2nm。这一结果表明，机器运动到加工表面的传递保真度被认为是约1nm。少

The purposes of this research are to develop a improved measuring method of the accuracy of motion of machine tool elements and also to analyse the transfer fidelity of the machine motion to the profile of machined surface.Based on an analysis of the so-called 3-points method, a new method is proposed for evaluating the radial runout of the rotor in an air spindle. The information on the true runout of the rotor can be obtained by this method without using the conventional reference sphere. With the aid of the newly developed reflective photo-electronic displacement sensor with subnanometer resolution and about 30 <mu> m working range, the runout of the air spindle is evaluated by the method proposed. The air spindle tested is shown to be operated within the rotational accuracy of about 50nm with the repeatability of less than 2nm.Furthermore, using the laser beam as a datum of straightness, the method is proposed for evaluating the accuracy of straight motion of machine tool elements … More with nanometer resolution. The principle of the method is high-sensitive detection of the displacement of the center of quadrunt photodiode which is fixed to the moving object and acts as a target of the laser beam. By employing the method proposed, the accuracy of straight motion on air slide and a specially designed elastic hinge subjected to forced deformation are measured and analysed. The accuracy of the straight motion of an air slide is successfully measured to be at the order of 0.1 <mu> m. In the short range of movement less than 100 <mu> m, the error motion of the elastic hinge is measured to be less than 1nm.Employing the machine elements as above, a series of cutting experiments was carried out and the surface profile is analysed. The form accuracy of the surface is observed to be less than 2nm in a specific crystal grain of brass when turned by a diamond tool. This results shows that the transfer fidelity of the machine motion to the machined surface is considered to be about 1nm. Less