Studies on ceramics micro machining with minute-size diamond quill

近年来，机电产品迅速向集成化、小型化方向发展，微加工已成为机电一体化领域的重要课题之一。特别是，主要部件通常由硬脆材料制成，如陶瓷。由于这些材料难以用一般的物理或化学方法加工，所以主要使用金刚石砂轮进行磨削。本研究的目的是研制一种微型金刚石笔微磨削机，并收集微磨削的基本数据。为了在直径小于1nim的毛管上获得标准磨削速度，需要主轴转速超过100,000 rpm。在这种微磨削中存在的其他问题是断裂和弹性变形。在此基础上，设计并生产了一种新型磨砂机。这台机器配备了一个最高12万转的高频主轴。该系统由静气轴承、监测磨削力的测功机和交流伺服电机驱动的X-Y工作台组成。通过在该机器上对陶瓷进行研磨，得到了以下结果：(1)磨削力与砂轮转速有关，主轴转速在12万转/分范围内越快，磨削力越小。(2)磨削力随工件进给速度的增加而简单增大，可通过操作进给速度来控制。(3)磨削力随磨削长度的增大而增大，随毛管金刚石粒度的增大而减小。(4)在垂直于切割槽的工件上加入振动，可显著降低磨削力。

Mechatronic products tend rapidly toward integration and smallization in recent years, so that micro machining has become one of the most important subjects. Especially, main parts are usually made of hard-brittle materials such as ceramics. Because these materials are difficult to process with general physical or chemical method, they are ground mainly using diamond wheels. The objects of this research are to develop a machine for micro grinding by using a minute-size diamond quill and to eam fundamental data of the micro grinding.In order to obtain a standard grinding speed on a quill of which diameter is below 1 nim, the spindle is required of rotational speed more than 100, 000rpm. Other problems in this micro grinding are breakage and elastic deformation of the quill. Based on the above concepts, a grinding machine was newly designed and produced. This machine was equipped with a high frequency spindle of 120, 000rpm in max., and was constructed of areo-static gasbearing, a dynamometer for monitoring the grinding force and a X-Y stage driven by an AC servo motor.Through grinding ceramics on this machine, the following results were obtained.(1)The grinding forces depend upon the wheel speed, the faster spindle speed in the range to 120, 000rpm leading to the lower grinding force.(2)The grinding forces increase simply with increasing workpiece feed speed, so that they can be controlled by operating the feed speed.(3)The grinding forces increase proportionally to grinding length, and those increasing rates decrease with increasing diamond-grit size of quill.(4)Adding vibration to the workpiece vertically to the cut groove reduces the grinding force notably.