磁粉电极放电印制表面功能微结构新方法研究

Although it is realized that functional surface microstructures have the potential to make great impacts in many engineering fields, it is still a great challenge for engineers to produce them with precision and quality. Micro-electrical discharge machining (m-EDM) is one of the few techniques that can produce micron-sized surface structures to high precision. Notwithstanding the advantages of m-EDM, to produce micro-tool electrodes to the precision requirement can be challenging; also the problem of serve tool wear is not easy to be overcome. With this problem in mind, this project puts forward a novel EDM method for fabricating surface microstructures. This method employs a magnetically held powder electrode, which acts as a soft brush, to ‘print’ functional surface microstructures with the aid of a mask pattern. The research involves a theoretical study of the material removal mechanism of the new process using electromagnetic and electro-discharge theories with particle dynamic and finite element methods. In addition, experimental studies will be conducted to verify the models. Special attention will be paid to the analyses of the assembly mechanism of the magnetically held powder electrode and its discharge mechanism, the dynamic behavior of the magnetized powder as well as the dissipation and the restoration mechanisms of the powder electrode. It is believed that the proposed new method can overcome the deficiencies of the traditional m-EDM method and becomes a high precision machining method with virtually no tool wear for the producing of micro/nano surface structures. This project has high applied and academic values.

表面功能微结构具有极大的应用前景，其制造问题引起了广泛的关注，微细电火花加工具有很高的精度，然而工具电极制作困难和损耗严重制约了其在表面功能微结构加工中的应用，为此本项目提出一种磁粉电极放电印制表面功能微结构的新方法，该方法将掩模工艺引入到火花放电加工领域，利用磁粉的柔性和放电加工的高精度的特性，精确地复制掩膜形状。该方法解决了常规电火花阵列电极制作困难及放电损耗大的难题，有望用简单电极实现表面微/纳结构的高精度加工。本课题拟应用电磁学理论、放电击穿理论、颗粒动力学法和有限元法，通过理论、试验和模拟仿真相结合的方式对新方法的加工机理进行深入研究，重点包括：掩膜约束分割下图案化磁粉电极的自适应形成机制；磁粉电极和工件间的微接触放电机理；磁粉电极放电损耗的动态自修复特征；材料微去除规律及微放电能量控制等。本项目的开展将为表面功能微结构的精密制造提供一种新的加工方法，具有重要的理论和现实意义。

本项目将掩模工艺引入到火花放电加工领域，采用磁粉电极放电印制表面功能微结构，利用磁粉的柔性和放电加工的高精度的特性，精确地复制掩膜形状,构建各类微结构功能表面。本项目的研究解决了常规电火花阵列电极制作困难及放电损耗大的难题，采用了简单的电极实现表面功能微/纳结构的大面积及高精度加工。研究过程中应用了电磁学理论、放电击穿理论、颗粒动力学法和有限元法，通过理论、试验和模拟仿真相结合的方式对新方法的加工机理进行深入研究，包括：掩膜约束分割下图案化磁粉电极的自适应形成机制；磁粉电极和工件间的微接触放电机理；磁粉电极放电损耗的动态自修复特征；材料微去除规律及微放电能量控制等。同时，本项目还开展了表面功能微结构的表征及磁粉放电沉积等工作，本项目的开展为表面功能微结构的精密制造提供一种新的加工方法，具有重要的理论和现实意义。