Explanation, of coating phenomena through electrical discharge in working fluid and its application to ceramics forming process

本研究旨在通过对电极材料的去除现象及其植入到工件上的研究，在工件表面进行精细加工，在金属表面覆盖陶瓷材料，并通过电火花加工加工绝缘陶瓷。为了控制间隙状态，将市面上的电火花加工机床改造成硬件模拟器，并制作了软件模拟器来研究间隙现象。结果表明：电火花精加工：在金属精加工中，粉末混合在工作液中分散了放电位置。放电分散性取决于粉末浓度、粉末直径和粉末内聚力。利用低粘着能的粉末，可以在低间隙条件下进行精密精加工。电火花表面改性的过程应分开考虑，即电极的磨损过程和工件上的附着过程。电极磨损过程c…更多的是高温高压下的熔融、汽化和/或剥落。从电极植入的磨粉通过重熔过程进入工件表面，重熔过程随堆层厚度的不同而变化。使用薄电极，可通过一系列放电、短路和爆炸过程实现小面积积聚。在单次放电法测量薄电极磨损长度的过程中，发现电极的形状发生了很大的变化，变成了针状。它可用于微细加工和测量探头。利用辅助电极进行绝缘陶瓷的电火花加工。上述混合粉末工作液在高速加工细小表面时非常有效。研究了陶瓷表面碳层的电学特性与放电条件的关系。此外，为新一代辅助电极开发了以碳为主的陶瓷焙烧工艺，使陶瓷加工更加实用。较少

In this study, we aimed to make fine surface on work piece, to cover metal surface with ceramics materials and to machine insulating ceramics by electrical discharge machining (EDM) through the investigation of removal phenomena of electrode material and its implantation onto work piece. In order to control gap conditions, we convert an electrical discharge machine in market into a hardware simulator and make a software simulator to investigate gap phenomena.The results obtained are summarized as follows;Finish machining by EDM: powder mixed in working fluid disperses discharge position in finish machining of metal. The discharge dispersion depends on powder concentration, powder diameter and powder cohesion. With powder of small cohesion energy, precision finish machining can be performed under low gap distance.The process of surface modification by EDM, should be considered separately, namely, wear process of electrode and accretion process on the work piece. Electrode wear process c … More onsists of melting, vaporization and/or flaking under high temperature and high pressure. Worn powder from the electrode implants onto work piece surface through remelting process which changes according to thickness of the piled layer. With use of thin electrode, accretion on small area can be achieved through a series of discharge, short circuit and explosion processes. In the process of measuring the wear length of a thin electrode by single discharge, it is found that the shape of the electrode changes drastically into a needle shape. It can be used for micro machining and measuring probe.Insulating ceramics machining by EDM was performed with assisting electrode. Powder mixed working fluid described above is very effective on high speed machining with fine surface. The electrical characteristics of carbon layer on ceramics were investigated in relation to discharge conditions. Moreover, baking process using mainly carbon on ceramics was developed for new generation of assisting electrode which makes the ceramics machining more practical. Less