Experimental investigation of the governing parameters of the electrostatic field–induced electrolyte jet micro electrical discharge machining on the silicon wafer

Abstract

Electrostatic field-induced electrolyte jet micro electrical discharge machining relies on the cyclic and pulsating electrical discharge between the tip of the fine jet, and the workpiece to remove the debris. To further explore the processing characteristics, the single-pulsating discharge experiments have been carried out with the NaCl electrolyte as the jet solution and the silicon wafer as the workpiece. The experimental results have shown that the crater size after a single electrostatic field-induced electrolyte jet discharge increases with an increase in the voltage applied between the nozzle and the workpiece and increases with an increase in the electrolyte concentration, but declines with an increase in the nozzle-to-workpiece distance. Moreover, the crater size has no direct relationship with the machining polarity, but slightly declines with an increase in the inner diameter of the nozzle. Finally, the conclusion that the parameters which influence the charge density on the electrolyte jet surface can determine the diameter of the single-discharge crater has also been drawn.

Research on Electrostatic Field-Induced Discharge Energy in Conventional Micro EDM

“…The power supply is a high-voltage DC with a voltage range of 0-10 kV. It can generate a strong electric field, which drags the electrolyte jet from the flat-headed nozzle toward the sacrificial electrode without any pump [18]. With the electrolyte jet extending, the field intensity increases and results in the plasma breakdown.…”

“…As a consequence, the usage of the E-Jet EDM energy generating technology in conventional EDM can be realized indirectly. Because the field jet's discharge energy may potentially be regulated to a very tiny scale [18], it can circumvent the discharge energy constraint in conventional micro EDM with the relaxation pulse generator [10] and the transistor-pulse generator [11]. This technology may provide an innovative method of pulsating discharge energy to micro EDM.…”

“…This approach removes material by plasma breakdown of a high-voltage DC electrostatic field between the flexible jet electrode and the workpiece, and utilizes the induced charges on the jet tip and workpiece as discharge energy. Zhang et al [18] also confirmed that by modifying the electrolyte concentration and electric parameters, the single pulse energy can be lowered to less than 10 × 10 −6 J. However, this pulse energy is difficult to transfer to conventional EDM since it is tightly coupled with the jet electrode generation process.…”

“…This work proposes a structure and tries to decouple this energy from the jet electrode to apply it into conventional micro EDM based on previous research [17,18]. The paper is organized as follows: Section 2 constructs a decouple test platform; Section 3 explains this decouple theory and the working principle of the machining process as well as the equivalent circuit.…”

Monitoring of material-removal mechanism in micro-electrical discharge machining by pulse classification and acoustic emission signals

“…These processes utilise the benefits of both conventional and unconventional material-removal process to overcome the limitations of the individual machining mechanisms. In the recent years, Zhang et al 1 proposed electrostatic field-induced electrolyte jet micro-EDM for silicon wafer. In the paper, the authors produced single-discharge between the tip of a fine jet of electrolyte (NaCl) and the workpiece (Si wafer) to remove the material.…”