An overview of techniques for monitoring and compensating tool wear in micro-electrical discharge machining.

Micro-electrical discharge machining (µEDM) is severely affected by tool wear and its process variants, which can lead to compromised precision and dimensional disruptions in micro-part production. Several attempts have been made to address this problem by suggesting offline and online (real-time) tool wear compensation strategies. Research efforts in this area have intensified over the last 20 years. However, most methods proposed were applicable only for a few work-tool combinations and in limited input process parametric settings. Instead of tool wear compensation, several research articles have focused on strategies to reduce the negative impact of tool wear on the quality of fabricated parts. The present study systematically reviews various investigations conducted in this area and aims to add cutting-edge compensation for tool wear to future inquiries. The articles reviewed here are explored in detail. Critical findings/innovations are classified into four categories: tool wear in µEDM, tool wear compensation techniques, and offline and online compensation methods.

Laser Micromachining in Fabrication of Reverse-µEDM Tools for Producing Arrayed Protrusions.

This paper focuses on the fabrication of high-quality novel products using a µEDM process variant called Reverse-µEDM. The tool plate required for the Reverse-µEDM is fabricated using Nd: YAG-based laser beam micromachining (LBµM) at the optimized process parameters. The Grey relation analysis technique is used for optimizing LBµM parameters for producing tool plates with arrayed micro-holes in elliptical and droplet profiles. Titanium sheets of 0.5 mm thickness were used for such micro-holes, which can be used as a Reverse-µEDM tool. The duty cycle (a combination of pulse width and frequency) and current percentage are considered as significant input process parameters for the LBµM affecting the quality of the micro-holes. A duty cycle of 1.25% and a current of 20% were found to be an optimal setting for the fabrication of burr-free shallow striation micro-holes with a minimal dimensional error. Thereafter, analogous protrusions of high dimensional accuracy and minimum deterioration were produced by Reverse-µEDM using the LBµM fabricated tool plates.