Development of a new mirror finishing process for the inner surface of capillary tube of 50〜100 micrometers in diameter by the application of magnetic field assisted machining

毛细管用于微机械和微型医疗器械等，但没有一种加工技术能够完成高达0.3μm Rz粗糙度的内表面。本研究将磁性研磨技术应用于微米管件精密内圆研磨加工，以建立精密内圆研磨加工技术。主要研究成果如下：1.内磁场辅助微米管光整加工实验装置、磁性工具的制作及光整加工实验利用永磁体与直径为0.1mm的钢琴丝工具之间的磁力作用于微米管内表面，实现了对微米管内表面的加工。设计了一种通过调节磁铁与微米管表面之间的距离来控制作用在钢琴丝刀具上的加工力的实验装置。在本研究中，进行了一个模型实验，使用一个平面工作，假设管的曲率半径为无穷大。2.研制了一种利用永磁体对微米管内表面进行高频振动光整加工的工具，并对加工性能进行了分析。精加工力通过外部永磁体作用于磁性工具。利用电磁场使磁性刀具产生高频振动运动是一种新的加工方法。观察了振动刀具的光整行为。线圈励磁电流与电磁工具振幅的关系。并阐明了刀具振幅与磁体与刀具之间距离的关系。经此工艺处理后，表面粗糙度由15.6μ mRz提高到0.15μ mRz。

The capillary are used to micro-machines and micro-medical treatment machines, etc. However, there is not a processing technology which is able to finish up to 0.3μm Rz roughness of the internal surface. In this research, we pay attention to the creation of the precise internal finishing technology for micron tubes by the application of the magnetic abrasive finishing. The results of this research are as follows.1.The experimental setup of a internal magnetic field assisted finishing process for a micron tube, production of magnet tool and finishing experimentThe machining force is acted on the micron tube internal surface by the magnetic force between a permanent magnet and 0.1mm diameter piano wire tool. We made an experimental setup which the machining force acting on the piano wire tool could be controlled by adjusting the distance between a magnet and micron tube surface. In this study, a model experiment was carried out using a plane work to assume the curvature radius of tube to be infinity. The finishing characteristics were examined, and the surface roughness has been improved from 0.14μm Rz to 0.09μm Rz.2.Development of a high frequency vibration tool-for the finishing the internal surface of a micron tube using a permanent magnet and the elucidation of finishing behaviorThe experimental setup was produced, and a micron tube of 2mm inside diameter is used. The finishing force is acted to the magnet tool by an external permanent magnet. Moreover, it is a new processing method which gives the high frequency vibrating movement to the magnet tool by the electromagnetic field. The finishing behavior of the vibration tool was observed. The relation between coil excitation current and amplitude of magnet tool,. and the relation of the amplitude of the tool and the distance between magnets and the tool was clarified.. The surface roughness has been improved from 15.6μm Rz to 0.15μm Rz by this process.