Electro-chemical discharge machining (ECDM) is a recent technique used to machine insulating materials like glass and ceramics. This paper presents the results of the combined effects of tool feed-rate and tool shape on the micro-machining of a quartz substrate using an ECDM process. The investigations show that a tool with a spherical tip provides a profile with a reduced entrance diameter and the overcut can be considerably reduced by controlling the tool feed-rate. © 2015 IEEE.

Saranya S

Department of Electrical Engineering

School of Electrical Engineering

Vellore Campus

Ravi Sankar A

Electronics

School of Electronics Engineering

Chennai Campus

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Effect of tool shape and tool feed rate on the machined profile of a quartz substrate using an electrochemical discharge machining process

2015 2nd International Symposium on Physics and Technology of Sensors (ISPTS)

Microfluidics is an emerging field giving rise to a number of scientific developments with wide applications in proteomics, genomics, DNA analysis, drug delivery systems and lab-on-a-chip. Among the various microfluidic structures, microchannels form an integral part of Lab-on-a-chip devices for clinical diagnosis. The geometrical accuracy and surface finish quality of the microchannels affect the performance of microfluidic systems, thereby demanding a precise microfabrication technique for realizing microchannels. Spark assisted chemical engraving (SACE) is an effective hybrid micromachining technique used for micro-structuring non-conducting substrates such as glass and ceramics. In the present work, we report on a room temperature coated thick insulating film for improving the quality of the microchannels realized using a SACE process. The insulator film coated around a tool electrode confines the spark discharges only to the bottom surface of the tool. Moreover, the proposed insulator coating methodology does not require any cost intensive equipment, carrier gases, vacuum units and a clean room environment. Experimental results demonstrate that for same process parameters a micro-channel fabricated using an insulated tool has its overcut reduced by 57.8% and machining depth improved by 19.53% with a smooth surface and regular edges as compared to the channels realized using an uninsulated tool. © 2017 Taylor &amp; Francis.

Materials and Manufacturing Processes

Fabrication of precise microchannels using a side-insulated tool in a spark assisted chemical engraving process

In the present study, a detailed experimental investigation is carried out on a constant velocity-feed drilling technique of an electrochemical discharge machining (ECDM) process to fabricate micro-holes on quartz substrates. First, cylindrical micro-tools of four different diameters (145 μm, 195 μm, 300 μm and 400 μm) with varying tool feed rates (TFRs) (0.3 μm s-1-1.9 μm s-1) are considered to study their influence on the precision of fabricated micro-holes while using a 30 wt% NaOH solution as an electrolyte, a machining voltage of 30 V and an initial working gap of 5 μm. Minimum micro-hole diameter and overcut were achieved at a TFR 0.8 μm s-1 for the cylindrical tools of all diameters. Considering 0.8 μm s-1 as an optimal TFR, the influence of tool shape on the quality metrics was investigated using a spherical shaped tool electrode having a ball diameter of 145 μm and a spindle diameter of 90 μm. A micro-hole realized using the spherical shaped tool shows that the entrance diameter, entrance overcut, central diameter and central overcut are reduced by 12%, 29%, 28% and 67% respectively as compared to that realized using a cylindrical tool for the same process parameters. Micro-holes with improved precision and aspect ratio are achieved without using cost intensive equipments, feedback mechanisms, coated tools and tool rotation. © 2018 IOP Publishing Ltd.

Journal of Micromechanics and Microengineering

Fabrication of precise micro-holes on quartz substrates with improved aspect ratio using a constant velocity-feed drilling technique of an ECDM process

Electrochemical discharge machining (ECDM) process is a recent non-traditional machining technique used for structuring insulating materials like glass and ceramic substrates. In this work, systematic experimental investigations have been carried out to study the electrical and 2-D machining characteristics of an ECDM process. The influence of various process parameters like electrolyte type, electrolytic concentration, tool travel rate (TTR) and applied voltage on the process characteristics have been studied. Two different electrolytes, i.e., KOH and NaOH with concentrations varying from 10 to 50 % have been used to study their effect on critical voltage (Vc) and critical current (Ic). A cylindrical tungsten carbide tool of diameter 0.4 mm with varying TTRs (ranging from 0.3 to 4 mm/min) and an applied voltage varying from Vc + 2 V to Vc + 5 V is used for realizing microchannels. The influence of these parameters on the quality factors such as geometric accuracy, surface smoothness and channel outlines are explored using the optical images of the machined channels. Experimental results demonstrate that precise channels with smooth surface, and regular channel edges can be obtained at an applied voltage of Vc + 4 V and TTRs between 1 and 2 mm/min. © 2016, Springer-Verlag Berlin Heidelberg.

Microsystem Technologies

Experimental investigations on the electrical and 2D-machining characteristics of an electrochemical discharge machining (ECDM) process

ECS Meeting Abstracts

Electrochemical Manufacturing to Support Industry 4.0 – Spark Assisted Chemical Engraving (SACE)

International Journal of Machine Tools and Manufacture

Enhancement of ECDM efficiency and accuracy by spherical tool electrode

CO2 laser micromachined crackless through holes of Pyrex 7740 glass

Surface and Coatings Technology

Micro- and nano-crystalline CVD diamond coated tools in the turning of EDM graphite

Journal of Materials Processing Technology

Chemical-assisted ultrasonic machining of glass

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