Electrochemical Discharge Machining Process Research Articles

Study of gas film characterization and its effect in electrochemical discharge machining

Electrochemical discharge machining (ECDM) is a promising method for the machining of hard, brittle, and inert materials such as ceramics and glass. Reducing the overcut is an important requirement for the ECDM process to emerge as a viable micro manufacturing method. The gas film quality is a critical factor contributing to the machining overcut in ECDM. This study focuses on the characterization of the gas film thickness and stability in ECDM. A full factorial parametric study of the gas film was performed for the electrolyte concentration, level of the electrolyte, the distance between electrodes and time of machining. Analysis of variance of the gas film thickness and stability of the gas film along with experimental verification revealed that the overcut in ECDM is affected by both gas film thickness and stability of the gas film. A lower concentration of electrolyte, with a lower level of electrolyte above the top surface of the workpiece and a higher distance between electrodes, for a lower time of machining constitute optimal machining condition to machine holes with less overcut and less taper.

On performance evaluation of textured tools during micro-channeling with ECDM

Electrochemical discharge machining (ECDM) is an emerging technique for machining of micro-channels on non-conductive materials. It utilizes a combination of chemical as well as thermal energies to machine the materials. The configuration of tool electrode plays important role to channelize these energies from tool electrode to work material. Thus, the appropriate selection of tool electrode configuration is essential to effectively utilize the energies during ECDM for achieving machining accuracy. The present investigation reports on textured tools for machining of micro-channels on borosilicate glass with ECDM. The underlying process mechanism is investigated. Textured tools provides micro gaps between the tool electrode and the workpiece surface and results in thin and stable gas films. The breakdown of thin and stable gas films produces high frequency low intensity discharges and consequently improves the machining performance. The textured tools in comparison with smooth surfaced tools exhibits improvements in material removal rate (MRR) by 19.27% and depth by 64.81%. Also the width overcut (WOC) and surface roughness were reduced by 122.26% and 26.96%, respectively. The flexibility to develop textured as well as smooth micro-channel surfaces by textured tools provides wider scope for fabrication of various micro fluidic devices. The effect of ECDM process parameters (voltage, pulse on-time, pulse off-time, feed rate and electrolyte concentration) with the use of textured tools was investigated. Multi criteria optimization using desirability approach predicted the parametric combination of applied voltage of 59 V, pulse on-time of 3 ms, pulse off-time of 3 ms, feed rate of 12 m m/min. and electrolyte concentration of 21%wt./vol., the optimum setting for micro-channelling by ECDM using textured tools.

DEVELOPMENT AND MANUFACTURING OF ARDUINO BASED ELECTROCHEMICAL DISCHARGE MACHINE

The machining of non-conducting materials is very difficult due to its brittleness and hardness properties. The electrochemical discharge machining (ECDM) process is the hybrid non-traditional manufacturing technology because it is combined with two processes namely electro-chemical machining (ECM) and electro-discharge machining (EDM) which can cut non-conducting and conducting materials. Hence from this view, the present work is undertaken to understand the development and manufacturing of ECDM setup based on Arduino. The 2D drawings are drawn by using AutoCAD software and 3D model is developed with CATIA software. The ECDM machine setup is manufactured accurately according to the 2D drawings and 3D model. The gravity feed mechanism is applied to workpiece materials and the speed of cathode tool electrode is controlled by using Arduino programming through the computer. The preliminary experimental trials were carried out and micro-hole drills on the glass and ceramic materials are successfully achieved. The present article provides fundamental and detailed building study of ECDM setup which includes information from the starting sketch up to the real prototype model. This work may be useful to make advanced machining setup as well as may solve the basic difficulties of new researchers in this field.

FEM of ECDM Process on Semi Conducting Materials

Electro Chemical Discharge Machining (ECDM) process has been developed as an innovative machining process for machining non-conductive materials. The various application of this hybrid process is used in many industries like nuclear, medical and automobile industries. The scope of ECDM in micro machining of semiconducting materials is still found to be promising challenge for researchers. Due to many advanced properties of silicon, its use in MEMS industries is enormous. Many researchers have carried out lot of empirical estimation for discharges in ECDM. However very less work has been reported in the modelling of the ECDM process. Present work mainly concentrates on Finite Element Modelling (FEM) of micro holes machined on silicon wafers with ECDM process. A thermal FEM of spark discharge in the ECDM is carried out. The results from FEM are compared with experimental results and are found to be satisfactory. The model developed can be used for prediction of MRR for a particular combination of workpiece-tool arrangement.

Characterisation of Micro Channels Machined with ECDM for Fluidic Applications

Electro Chemical Discharge Machining (ECDM) process is an innovative micro machining process to machine electrically conducting and non-conductive materials for micro level application. In this paper an attempt has been made to machine micro channels with ECDM process for micro fluidic application. Micro channels are machined for three different speeds for borosilicate glass with tungsten copper alloy tool of 300 micron diameter with optimized process parameters. Flow rate across micro channels are measured and are found to be reliable for micro fluidic application. Micro channels are found to have good surface finish when machined with optimal conditions. Micro ECDM process is found to be cheaper and faster process compared to existing machining operations in non-conducting materials.

Micro Machining In ECDM Process With Tool Modification

Machining of hard materials is difficult and even impossible with conventional machining processes at high accuracy. Electro Chemical Discharge Machining (ECDM) process has evolved as a hybrid machining process to machine electrically conducting and non-conducting materials. In the present study micro machining is carried out on borosilicate glass with tool modification in ECDM process. Machining is carried out on borosilicate glass with micro drills of different diameters. The machining with micro drills are found to give minimum Radial Over Cut (ROC). Also the regular shape micro holes are obtained with drill bits tool. So from the experimental observations tool modification in the form of drill bits has found to give tremendous improvement in terms of micro-hole roundness and surface features.

Effect of Powder Mixed Electrolyte in ECDM Process

Electrochemical discharge machining (ECDM) process is a newer and most potential non-conducting machining process under the category of hybrid machining process in which the material is removed through thermal energy- melting followed by evaporation and chemical etching. The process is important since it can machine a variety of materials including metals, ceramics, composites, alumina, glass, etc. In the present paper experimental work is carried on Polypropylene (PP) materials with graphite particle powder mixed electrolyte in order to improve the machining characteristics. In this present work investigation is carried out on the material removal rate while machining with and without the use of powder mixed electrolyte. For this purpose three process parameters were selected and experimental layout was developed using Taguchi method. Multiple discharging effects were created on the work piece surface due to conducting graphite particles in electrolyte. The results are optimised for higher material removal rate.

Effect of Electrolyte Level during Electro Chemical Discharge Machining of Glass

Electro chemical discharge machining (ECDM) is a hybrid machining process. This process has potential application for micro fabrication in nonconductive work materials such as glass. Micro fabricated holes and channels on glass are widely used in micro electro mechanical systems and bio medical devices. ECDM process takes place in an electrolytic cell consisting electrolyte upto certain level above workpiece. This electrolyte level affects the machining efficiency and quality of fabricated micro hole or channel. In this article, the electrolyte level was varied from 0.1 to 4 mm to investigate the effect on process responses of ECDM during fabrication of micro hole in glass. The process responses were material removal rate, depth of cut, heat affected zone and overcut. The effect of electrolyte level was characterized by spark discharge on voltage time wave form and microscopic images. The results revealed that an optimal value of electrolyte level is required for precise machining.

Taguchi’s Methodology Based Electrochemical Discharge Machining of Polymer Matrix Composites

The polymer composites has gained its reputation among advance materials in recent years due to their prominent mechanical properties. Still, the machining of these materials induces lots of problem because of their fibrous nature. In this paper, an attempt has been made to machine micro hole in polymer matrix composites (PMCs) using electrochemical discharge machining (ECDM) process. The experimentation was based on Taguchi’s methodology and results were analyzed qualitatively as well as quantitatively. Voltage, electrolyte concentration and inter-electrode gap were used as input process parameters whereas material removal rate (MRR) was observed as output quality characteristic. The state of the machined hole was analyzed by the scanning electron microscope (SEM). Analysis of variance (ANOVA) was used to find out most influential process parameters during ECDM of PMCs for each response.

Machining of Carbon Epoxy Composite using High Speed Electrochemical Discharge Machining

Though fiber reinforced composite products provide the possibility of making holes during moulding itself, many times machining of composites becomes unavoidable. The unconventional machining processes can be used effectively for such machining applications. Electrochemical discharge machining (ECDM) method is a promising alternative method for drilling such composites. ECDM combines the action of electro chemical machining (ECM) and electro discharge machining (EDM). The ECDM performance parameters like material removal rate (MRR) and radial over cut (ROC) both are affected by the speed of tool rotation. In this process, high-speed tool rotation is used to improve the material removal rate and to reduce radial over cut for composite material. This paper discusses the effect of speed of tool rotation on the performance of ECDM. This study addresses the performance of drilling of carbon fiber-epoxy composites, in an ECDM process to study the effect of parameters like speed of tool rotation, feed rate, voltage, and electrolyte concentration and their effect on the process. The study can be useful to arrive at a suitable set of parameters in high speed ECDM.

Experimental investigation of micro wire electrochemical discharge machining by using a rotating helical tool

The wire electrochemical discharge machining (WECDM) process is an effective way to machine high aspect ratio of micro-structures on non-conductive, hard, and brittle materials like quartz glass and ceramics. In this paper, the newly developed micro WECDM by using a rotary helical tool is proposed. Many experiments are conducted to investigate the machining localization of the WECDM with a rotating helical tool. The present study discusses the effects of machining parameters like applied voltage, frequency, duty factor, spindle speed, and feed rate on the side gap during the slicing of glass workpiece by using the developed WECDM setup. Experimental results demonstrates that the side gap rises with the increase in applied voltage and duty factor and reduces with the rise in frequency, spindle speed, and feed rate. Series of kerfs with 138μm width are fabricated successfully by the optimized parameters. The complex closed structure, the high aspect ratio kerf, and the pattern structure with high aspect ratio are obtained by this method.

Experimental investigation of surfactant-mixed electrolyte into electrochemical discharge machining (ECDM) process

Using electrochemical discharge machining (ECDM), is the most appropriate method to create microchannels on glass pieces by applying chemical and thermal phenomena simultaneously. Several parameters affect the quality of microchannels. Thickness of gas film surrounded the tool-electrode is one of the most effective parameters, which thinner gas film would result in higher machining quality. In this study, according to the theoretical analysis of the single gas bubble formed at the tool electrode surface, it has been found that the wettability of tool electrode and surface tension between the bubble and electrolyte affect the gas film thickness. In the experiments, two most widely used surfactants which are anionic surfactant Sodium dodecyl sulfate (SDS) and cationic surfactant Cetyltrimethylammonium bromide (CTAB) in various concentrations, were dissolved in the 25wt% KOH and NaOH alkaline solutions in order to reduce the gas film thickness by affecting the physicochemical properties of the electrolyte and the wettability of the electrode. The results obtained from the experiments indicated that in the presence of surfactant microchannels with higher material removal rate (MRR), lower overcut and heat affected zone (HAZ) were fabricated. Also, due to decrement of thermal conductivity and increment of viscosity of the electrolyte in the presence of surfactant, the surface quality of microchannels were improved. For example, at a voltage of 35V and presence of 0.036wt% CTAB in KOH, the surface quality improved 73% and the hardness of channel edge enhanced 144%. Increase in hardness of channel edge, indicates that the HAZ is reduced. Among different concentrations of surfactants, the critical micelle concentration (CMC) has the most influence on the machining performance. Since the cationic surfactant CTAB has lower CMC and also enhances the chemical etching by presenting more OH radicals on the glass, it has more influences on the process outputs compared to the anionic surfactant SDS.

Investigation on Electrochemical Discharge Micro-Machining of Silicon Carbide

Electrochemical discharge machining (ECDM) process has great potential to machine hard, brittle and electrically non-conducting materials in micron range. The objective of this paper is to investigate into electrochemical discharge micro-machining on electrically semi-conductor type silicon carbide (SiC) material so as to study the effects of applied voltage, electrolyte concentration and inter-electrode gap on material removal rate (MRR) and radial overcut (ROC) of micro-drilled hole. Experiments were conducted based on L9 array of Taguchi method with stainless steel µ-tool of 300µm diameter using NaOH electrolyte. An attempt has been made to find out the single as well as multi-objective optimal parametric combinations for maximum MRR and minimum ROC. The single-objective parametric combinations were selected as 45V/20wt%/20mm and 25V/20wt%/40mm for maximum MRR and minimum ROC respectively whereas multi-objective optimal parametric combinations was found as 25V/20wt%/40mm. Further mathematical models have been developed between the above machining parameters and characteristics.

Fabrication of high-aspect-ratio microgrooves using an electrochemical discharge micromilling process

In this study, we created high-aspect-ratio microgrooves in hard, brittle materials using an electrochemical discharge machining (ECDM) process by introducing microtextured machining tool. To enhance the electrical discharge activity, the morphology of the tool side surface was treated via micro-electrical discharge machining to produce fine microprotrusive patterns. The resulting microtextured surface morphology enhanced the electric field and played a key role in improving the step milling depth in the ECDM process. Using the FEM analysis, the evaluation of the field enhancement factor is also addressed. Our experimental investigation revealed microgrooves having an aspect ratio of 1:4, with high geometric accuracy and crack-free surfaces, using one-step ECDM.

Study of the current signal and material removal during ultrasonic-assisted electrochemical discharge machining

Electrochemical discharge machining (ECDM) is a cost-effective machining process used to shape non-conductive materials such as glass and ceramics. The process can overcome poor machinability of hard and brittle materials. Different types of physical phenomena can be added to the ECDM components to improve the machining efficiency. As the main target of this paper, ultrasonic vibration was integrated to the cathode of the ECDM process (UAECDM), which resulted in vibration concentration only to the machining zone. In order to design the experimental configuration, modal analysis was used. Machining speed was the main output of this investigation. Gas film and electric discharge were two main physical phenomena during ECDM. The thickness of gas film, location, and pattern of discharges were determined, experimentally. Also, current signal was a useful tool that could record significant details of involved mechanisms and phenomena during machining. Images of gas film showed that the application of ultrasonic vibration decreased the thickness of gas film by 65%. In addition, the vibration amplitude of 10 μm created the most uniform current signal, which had a considerable effect on the material removal rate (MRR). Results showed that all levels of vibration amplitude increased the machining speed during discharge and hydrodynamic regimes of the machining process.

On performance studies during micromachining of quartz glass using electrochemical discharge machining

The electrochemical discharge machining is a highly stochastic process involving a number of complex parameters. Controlling of these process parameters simultaneously to fetch the best possible performance is a difficult task. Determining an optimal parametric combination has become complex owing to interdependency of the parameters. In this work, the authors have made an attempt to establish the optimal combination of control parameters for machining of micro-channels on quartz glass. Taguchi’s standard orthogonal array (L9) with Grey relational analysis (GRA) approach was used to establish the optimal parametric conditions for reducing the Width overcut (WOC) of micro-channels and increasing the Material removal rate (MRR). In order to optimize MRR and WOC together, the optimal combination of the selected control variables was obtained using the GRA. The experimental results showed the effectiveness of the adapted method to indicate the performance of the electrochemical discharge machining process.

Review on Material Removal Technology of Soda-Lime Glass Material

Objective: To provide comprehensive literature survey of machining process in soda lime glass with reference to the conventional and non-conventional material removal process. Methods/Statistical Analysis: For more convenient understanding, the various processes, research and advanced progress in this field is presenting in table format. The ascending pyramid diagram shows progress of advanced researches on soda lime glass machining. The percent contribution of machining processes has been calculated and explained in a pie chart. Findings: There are totally eight machining processes used by various researchers to treat the soda lime glass. From which, Laser Machining Process and Electrochemical Discharge Machining Process showing highest contribution i.e. 22% are because of its advanced and wide range of applications in various fields. Whereas 6% contribution is observed for Abrasive Jet Machining process and micro grinding process, which is used at very low scale, it may be due to an extensive range of limitations. Application/Improvement: The present study is a first attempt towards the literature review on soda lime glass material. This review may be helpful to classify and select the most significant machining method to work with soda lime glass material.

Quality improvement of electrochemical discharge machining process using firefly algorithm: a case study

In this paper, the firefly algorithm is employed with the RSM (response surface methodology) to investigate the electro chemical discharge machining (ECDM) process in terms of effects of the process parameters on the output quality characteristics, as well as, to set the optimal process parameters for achieving the better product quality. Firefly algorithm is a powerful nature inspired metaheuristic algorithm that can solve complex optimisation problems, both, single objective and multi-objective optimisation problems. It is noticed that firefly algorithm can find the optimal solution, efficiently, within very less timescale. It is also very effective in predicting the parametric trends of responses. The results obtained by using firefly algorithm for parametric optimisation of ECDM are compared with those derived by the past researchers, which prove the applicability and effectiveness of this algorithm in enhancing the performance of the ECDM process.

Quality improvement of electrochemical discharge machining process using firefly algorithm: a case study

In this paper, the firefly algorithm is employed with the RSM (response surface methodology) to investigate the electro chemical discharge machining (ECDM) process in terms of effects of the process parameters on the output quality characteristics, as well as, to set the optimal process parameters for achieving the better product quality. Firefly algorithm is a powerful nature inspired metaheuristic algorithm that can solve complex optimisation problems, both, single objective and multi-objective optimisation problems. It is noticed that firefly algorithm can find the optimal solution, efficiently, within very less timescale. It is also very effective in predicting the parametric trends of responses. The results obtained by using firefly algorithm for parametric optimisation of ECDM are compared with those derived by the past researchers, which prove the applicability and effectiveness of this algorithm in enhancing the performance of the ECDM process.

Multi-objective optimization of electrochemical discharge machining processes: a posteriori approach based on bird mating optimizer

In the modern manufacturing scenario, efforts are continuously being made to improve the performance of advanced machining processes. Electrochemical discharge machining (ECDM) is a hybrid non-traditional machining (NTM) process, which makes use of the combined advantages of two single-action NTM processes, i.e. electrical discharge machining and electrochemical machining. As a result, the performance characteristics of ECDM process are considerably different from those of the two single-phase processes with respect to productivity, accuracy and surface quality. Selection of the optimal process parameters is always crucial towards fully utilizing the benefits of ECDM process. In this paper, an a posteriori approach based on the novel bird mating optimizer (BMO) is applied for multi-objective optimization of ECDM responses. In this approach, the complete spectrum of non-dominated Pareto optimal solutions, from which the process engineers can easily choose the desired parametric setting depending on the application domain, is developed. It is much more useful from a practical standpoint than a priori approaches reported in the literature. The BMO is also used to predict the overall trends of the multi-parameter dependent responses, without the need of holding any of the process parameters constant during analysis.