https://ro.uow.edu.au/cgi/viewcontent.cgi?article=1759&context=eispapers1

A review of modern advancements in micro drilling techniques

Technology development has led to the need of micro and miniaturized products in the field of automobile, aerospace, electronics, medical implants, biomedicine, robotics, and so on. Micromachining is the key technology to satisfy the need of the industry in terms of functionality and miniaturization in size. In this article, state-of-the-art review on tool-based micromachining processes such as microturning, microdrilling, micromilling, electric discharge micromachining (Micro-EDM), and electrochemical micromachining (Micro-ECM) has been carried out. The review begins with an overview of micromachining, classifications, and discussions about different aspects of tool-based micromachining processes. The research works carried out for the past 10 years are analyzed in terms of materials perspective, process parameters, size effects, performance characteristics, condition monitoring, product development, micro features generation, and fabrication of micro tools. A statistical analysis has been performed with...

A Review on Current Research Aspects in Tool-Based Micromachining Processes

Electrical discharge machining has emerged as one of the most accepted non-traditional machining methods that have the capability of attaining complex shapes and better feature size in difficult-to...

Micro-electrical discharge machining of difficult-to-machine materials: A review:

Effect of tube-electrode inner structure on machining performance in tube-electrode high-speed electrochemical discharge drilling

Micro electric discharge machining (μ-EDM) is a widely used process for machining of difficult to machine materials. The occurrence of arcing and short circuiting in micro electric discharge drilling (EDD) is a common problem which limits the aspect ratio achieved during the process. The present study is focused on the improvement in response characteristics by eliminating the occurrence of arcing and short circuiting. These problems can be addressed by modifying the tool electrode geometry. Although, EDD using shaped tool electrodes improve response characteristics as proven by the previous studies, but time spent in electrode fabrication must also be considered as it affects the overall productivity. Considering the literature related to EDD using shaped tool electrodes, the proposed electrode has been found to have minimum electrode fabrication time i.e. 9 min for an electrode length of 3.2 mm. Therefore, the proposed electrode is capable of producing holes of high aspect ratio with minimum electrode fabrication time. The proposed electrode was also found to be effective in eliminating the accumulation of debris in the machining zone. Moreover, the need of flushing during the process has been totally eliminated making it a self-flushing electrode. The mechanism of removal of debris is well explained based on the images captured using a high speed camera. The performance of the proposed electrode was evaluated with respect to response characteristics such as material removal rate, tool wear rate, aspect ratio, taper angle and corner radius of the drilled hole. A substantial increase of 300% in aspect ratio was recorded using the designed electrode as compared to the solid cylindrical electrode for the hole diameter of 0.8 mm.

Productivity improvement of micro EDM process by improvised tool

There is a growing interest in the machining of micro-holes with high aspect-ratio in difficult-to-machine alloys for the aerospace industry. Processes based on electro discharge machining (EDM) and developed for the manufacture of both micro-electrode and micro-hole are actually used, but most of them involve micro-EDM machines. In this work, the influence of EDM parameters on material removal rate, electrode wear, machining time and micro-hole quality when machining Ti6Al4V is studied. Due to an inefficient removal of debris when increasing hole depth, a new strategy based on the use of helical-shaped electrodes has been proposed. The influence of helix angle and flute depth with respect to process performance has been addressed. Main results include 37% reduction in machining times (hole diameter 800 μm) when using electrode helix angle of 45° and flute-depth of 50 μm, and an additional 19% with flute-depth of 150 μm. Holes of 661 μm diameter and as much as 6.81 mm depth, which yields in aspect ratio of 10:1, have successfully been machined in Ti6Al4V.

Endika Perez

Papers

Experimental study on micro EDM-drilling of Ti6Al4V using helical electrode