The state of the art of electrical discharge drilling: a review

Abstract

Electrical discharge machining (EDM) is one of the most widely used non-conventional methods to machine electrically conductive materials in the manufacturing industry because of its strong capability in machining difficult-to-cut materials irrespective of their strength and hardness. Electrical discharge drilling (EDD) is an important variant of EDM. Due to the limitation of conventional drilling processes, special holes, particular those with high aspect ratios on hard-to-cut materials, can only be drilled by EDD. Extensive research has been carried out to improve the efficiency and quality of the EDD process by using different approaches, such as assisted EDD and powder-mixed EDM drilling aiming to improve the material removal rate (MRR), tool wear rate (TWR), surface quality and accuracy. This paper provides a comprehensive review of the EDD process. Different methods were compared; the advantages and disadvantages of each process were summarised; state-of-the-art technologies and the latest development were introduced, and research trends and new directions were presented.

Experimental Investigations and Effect of Nano-Powder-Mixed EDM Variables on Performance Measures of Nitinol SMA

“…Greater temperatures caused by high-frequency sparks result in a number of flaws such as poor surface finish, debris deposition, substantial dimensional deviations, the creation of cracks and pores, and decreased efficiency [ 15 , 16 ]. Finding a solution that will facilitate better MRR while minimizing SR, TWR, and other surface imperfections is very important.…”

Hole-Making in D2-Grade Steel Tool by Electric-Discharge Machining through Non-Conventional Electrodes

“…EDM drilling is considered an excellent choice for machining deep and narrow holes regardless of a material's hardness or location, whereas die-sinking EDM works well to machine perpendicular walls of die and molds [32]. The significant feature of EDD is its ability to machine high-aspect ratio holes [33]; however, it has the common limitation that the electrode wear is rapid compared to wear during die-sinking EDM. Thermal defects such as a recast layer are among other reported limitations of electric-discharge drilling.…”

Parametric assessment of electrical discharge drilling on plasma sprayed functionally graded Al/Al2O3 coating on Al6061-T6 faceplates

“…Several rotating drill bits with different forms are used to drill holes in traditional machining processes. Because of the material's high strength and hardness, low stiffness, poor cooling effects, and challenges with chip removal, drilling high-quality holes, especially deep holes, in functionally graded coated (FGCed) aerospace structures is challenging [7].…”

“…These techniques have helped to bring down the rate of tool failures and improve the quality of machined surfaces. In generating hole structures, particularly those with small diameters and high aspect ratio holes on difficult-to-cut materials, EDM technology, also termed electrical discharge drilling (EDD), is being used [7,8]. The shortest inter-electrode gap occurs when electrical sparks are produced during the EDM process, triggering dielectric breakdown and the widening of plasma channels between the electrodes.…”