Intensive Study on the Electrostatic Field Induced Electrolyte Jet Micro Electrical Discharge Machining

Abstract

The micro tool electrode fabrication and minimum discharge energy generation are two main problems in micro electrical discharge machining (μEDM). This paper proposed an electrostatic field induced electrolyte jet μEDM method. In this method, the nozzle with electrolyte filled in and the workpiece are connected to two terminals of the high voltage power supply. With the intense electric field in between, the fine jet can be generated from the nozzle outlet with the combined effect the electric forces of the induced charges and surface tension on the jet surface. When the jet is approaching the workpiece, the discharge between the tip of the fine jet and the workpiece can be generated and removed debris from the workpiece surface. In the machining process, the fine jet generated from the nozzle is used as the tool electrode and the electrostatic field induced charges on the fine jet surface is treated as the source of the discharge energy. In this paper, the gradual growth of the fine jet from the nozzle outlet is intensively studied with the help of the digital camera and the diameter of the tool electrode is approximate to 5μm. The discharge energy is calculated by measuring the discharge current and discharge voltage during the discharge process and the discharge energy pre pulse is by far smaller than 10-8 J. In the single discharge experiment, the micro pit as small as 1μm in diameter can be found on the machined area. The discharge phenomena and component identification on the machined areas have intensively confirmed the machining mechanism of the proposed E-Jet EDM method.