Microhole drilling through electrochemical processes: A review

ABSTRACT

Day-to-day interest is growing in the drilling of high aspect-ratio deep microholes in various hard-to-machine and newer materials. Besides cost-effectiveness in the manufacturing process, an accurate dimension with the good surface finish is essential for microhole drilling. The conventional methods encounter various problems such as residue stresses, heat generation near cutting zone, high tool-wear, etc. Electrochemical microdrilling (ECMD) is one of the cost-effective techniques, provide a better alternative in drilling microholes with reasonably accurate dimensions and good surface finish in various industrial applications especially in computer, electronic, and aerospace industries. This article reviews current researches and developments of electrochemical processes for circular microholes drilling. It highlights the effects of various key factors (such as the development of microtools, electrolyte, inter-electrode-gap monitoring and control, etc.) on the aspect-ratio and accuracy of circular microholes, produced by ECMD. For further research, it will open up various challenging opportunities, especially in the field of (i) development and handling of microtool electrodes, (ii) development and handling of electrolytes medium, (iii) development in monitoring and controlling techniques of inter-electrode-gap, and (iv) development in strategies for process control for drilling high quality, deep and high aspect-ratio circular microholes into hard-to-machine materials using ECMD.

KEYWORDS:

• µECM
• electrolyte
• inter-electrode gap
• microdrilling
• microhole
• microtool

Abbreviations::

• ECM: electrochemical machining
• EDM: electrodischarge machining
• ECMD: electrochemical microdrilling
• EDMD: electrodischarge microdrilling
• PD: pulse duration
• PI: pulse interval
• DC: Direct current
• T: machining time
• V: machining voltage
• MRR: material removal rate
• EC: electrolyte molar concentration
• EG: electrode gap
• F: frequency of pulsed power supply
• FR: feed rate
• I: average current
• EF: electrolyte flow rate
• JP: jet pressure
• RS: rotating speed
• Tof: pulse off time
• Ton: pulse on time
• SS: stainless steel
• WC: tungsten carbide
• DCy: duty cyle
• L: length of tool
• Ft: frequency of tool
• Fw: workpiece frequency
• IG: interelectrode gap
• Δd: difference between inlet and exit diameters of microhole

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.