Development of Micromachines by Use of Ultraprecision Milling Machine

随着电子和光学器件的快速发展，对超精密加工和微制造技术的要求越来越高。微制造技术，近年来被称为微加工技术，在蚀刻和光刻技术的基础上，在大规模集成电路制造领域发挥着重要的作用。然而，蚀刻和光刻技术存在材料种类有限和三维形状生成复杂的问题。另一方面，该加工技术具有加工效率高、材料选择范围广、表面粗糙度好等优点。为微机械和/或微机械生产金属微部件的需求正在迅速增加。因此，本研究首先研究了在超精密铣床上使用微加工技术制造毫米尺寸的微型零件，该铣床由z-运动工作台、可定位主轴作为c-旋转轴和x-运动工作台组成。主轴与由单晶金刚石组成的假球立铣刀安装在x台上。以螺旋桨的CAD数据为基础，设计了一种新的制造工艺，以制造直径为3mm的螺旋桨为例。结果表明，加工后的表面粗糙度为0.1 mm的螺旋桨可以安装在直径为0.7 mm的微电机轴上，并且工作良好。针对脆性材料加工的必要性，采用车床式超精密铣床和改进的伪球立铣刀，对玻璃进行了延性模式下的超精密三维微加工。实验推导了延性模切的条件，发现延性模切可以将带有裂纹的粗切面转变为镜面。因此，可以获得直径为1 mm，高度为30 mm，表面粗糙度为50 nm （Rmax）的玻璃掩膜。

With the rapid Progress of electronic and optical devices, ultraprecision machining and micromanufacturing technologies are increasingly required. Micromanufacturing technology, called micromachining in recent years, plays an important role in the field of LSI manufacture on the basis of etching and lithography technologies. However, etching and lithography technologies have limitation of kinds of material and complicated 3-dimensional shape creation. On the other hand, the machining technology has advantages of high machining efficiency, wide spectrum of material selection, good surface roughness and so on.The requirement of producing metallic microparts for micromachine and/or micromechanism is increasining rapidly. Thus, the study deals at first with manufacturing of tiny parts in mm-size, using a micromachining technology by an ultraprecision milling machine, which consists of z-motion table, positionable spindle on it as c-rotational axis and x-motion table. The spindle with a pseudo ball end mill composed of a single crystal diamond is mounted on the x-table. A new manufacturing procedure is devised to create a propeller of 3 mm in diameter as an example of microparts, based on CAD data of the propeller. As a result, it is found that the machined propeller with the surface roughness of 0.1 mum can be mounted to the micromotor shaft of 0.7 mm in diameter and works well.In terms of the necessity of processing brittle materials, the study secondly deals with ultraprecision 3D micromachining of glass in the ductile mode, using the lathe-type ultraprecision milling machine and improved pseudo ball end mills. The condition of ductile mode cutting is experimentally derived, and it is found that the roughly cut surface with cracks can be changed to the mirror surface by the ductile mode cutting. As a result, it becomes possible to obtain a glass mask of 1 mm in diamter and 30 mm in height with the surface roughness of 50 nm (Rmax).