Micro-Machinability Study in Ultraprecision Metal Cutting

随着金属切削的切削深度降低到亚微米，各种迄今为止未触及的现象显然是表面光洁度和几何精度的决定因素。材料在极端尖端周围的微性能就是一个例子。本工作的目的是分析微观现象，并提出微可加工性，即“亚微米角度的可加工性”及其物理图像。本文的研究结果如下：1。为分析微加工现象，设计并制造了专用的切削装置。它具有60 mN/nm的高刚度，进给机构具有纳米级分辨率，内置0.1 gf分辨率、1 gf/nm刚度的高精度测功机。采用有限元法对金刚石车削加工表面晶界处观察到的微步进行了分析。微步是衡量微切削性能的一个指标，它归因于组成表面的晶粒弹塑性性能的各向异性和非均匀性。此外，还考虑了刀具与工件材料的亲和力对超精密加工中最小切削厚度的影响。通过模拟高温下金刚石与工件材料的界面试验，分析了金刚石与工件材料的附着力和刀具损伤。根据实验结果，提出了氧化对刀具磨损的重要意义。因此，提出了一种可能的磨损控制技术。

With decrease in depth of cut in metal cutting to submicrometer, a variety of phenomena untouched so far appear explicitly as determining factors for the suface finish and the geometrical accuracy attainable. Micro-performance of materials at around the extreme cutting edge is an example. The purpose of the present work is to analyse the micro-phenomena and to propose the micro-machinability defined as "the machinablity in terms of submicrometric point of view" and its physical pictures. The results obtained in the present work are as follows.1. For analysis of micro-machining phenomena, a special cutting apparatus was designed and manufactured. It has features of high stiffness of 60 mN/nm, nanometer resolution in infeed mechanism and the built-in high precision dynamometer of 0.1 gf resolution at 1 gf/nm stiffness.2. Using FEM, micro steps observed at grain boundaries on the surface finished by diamond turning was analysed. The microsteps, a measure of micro-machinability were attributed to the anisotropy and inhomogeneity in elastoplastic properties of the grains which compose the surface. Also, the minimum thickness of cut in ultraprecision machining was assumed to be affected by the affinity between tool and work materials.3. By using a simulated interfacial test for diamond and work materials at elevated temperature, analyses were made on the adhesion and tool damage, the other measure of micro-machinability. As a results of the experiment, a proposal is made for the significance of oxidation on tool wear. Consequally a possible technique is presented for the wear control.