The tool electrode investigation of electrostatic field-induced electrolyte jet (E-jet) electrical discharge machining

Abstract

This investigation addresses concerns in microelectrical discharge machining (EDM) such as high tool electrode preparation cost, tool electrode wear, and tool electrode compensation by proposing a new electrostatic field-induced electrolyte jet tool electrode. This method utilizes the theory that in a strong direct current electric field, the electrolyte at the capillary tube outlet can form a Taylor cone based on the balance of electric field force and surface tension. Coupled with the increase of electric field intensity, a very fine jet can eject from the tip of the Taylor cone, and this induced charge on the tip leads to a discharge to the workpiece which can remove debris from the workpiece surface. After the discharge, the induced charge at the tip is neutralized, leading to the surface tension outweighing the electric field force and the withdrawal of the fine jet. As a result, the cyclic pulse discharge process is generated. During the process, the tip of the fine jet serves as the tool electrode. This paper identifies this cyclic pulse electrolyte jet tool electrode generation and discharge process in action and tests the machining ability of this tool electrode on a silicon wafer. This electrolyte jet tool is also shown to have no wear or compensation issues, and the cost compared to conventional EDM is shown to be small.

An experimental study on the effect of parameters on the depth of crater machined by electrostatic field–induced electrolyte jet micro electrical discharge machining

“…At the time when the fine jet is about to touch the workpiece, the short-lived plasma will generate in between, and the heat generated by the plasma will lead to the melting or vaporization of the material. 13 The random characteristics of ions in the plasma between the tip of the fine jet and workpiece during the discharge result in the tips and caves on the bottom of the crater after a single discharge. When reversing the polarity, the induced charge on the surface of the Taylor cone will reverse.…”

“…13 The machining ability of this method and the tool electrode preparation, generation, discharge, and restoration processes have already been verified by several experiments. 14 However, the application and popularization of this method require a thorough study of the effect of machining parameters on this electrostatic fieldinduced electrolyte jet EDM.…”