Electrochemical Machining Process Research Articles

Feasibility and Optimization of Electrochemical Machining for 6061 Aluminum alloy

The request depending on electrochemical machining (ECM) technique has progressed in a large scale according to different points of view such that; cost or energy consuming, environment protection, reliable performance etc. This work aims to predict and optimize ECM process parameters for important, economic and applicable material (6061 aluminum) by employing L9 Taguchi method as a design of experiment (DOE) approach. This has led to experimental designing, developing a mathematical model and optimizing the entire ECM operation. This was carried out by controlling the chosen process variables (voltage, flow rate speed and electrolyte concentration) in order to optimize and predict the responses namely material removal rate (MRR) and dissolution rate. ANOVA, 3D contour graphs and perturbation plots have been employed to identify the analysis of variance of each response as well as to show the significant model terms. The process parameters i.e. voltage, flow rate speed and electrolyte concentration have been ranged to be 15-25V, 8-12 l/min and 3.36-7 % respectively. In both cases of MRR and dissolution rate the voltage parameter has seen to be the prominent factor that affects the responses so as to investigate highest value of MRR and dissolution rate, 0.477 g/min and 2.149 mm/min, respectively. This has been confirmed due to the results obtained from the ANOVA analysis which shows maximum F-valu for the voltage in the MRR and dissolution rate such that; 921.91 and 1608.34 respectively. But, still there was a considerable enhancement in the MRR and dissolution rate due to the increment in the flow rate speed and electrolyte concentration. Model validation has been carried out and thus the results invistigated that all the considered models were adequate since the residuals in prediction of each response were ignored, because the residuals were semi-matched with the diagonal line. Optimizations of responses were performed in this work numerically by using two types of criteria (restricted and non-restricted). According to these criteria, important increment in the MRR can be obtained which reaches 37%. A considerable enhancement has been obtained in the dissolution rate due to the comparison between the two criteria which results in increment by around 11% as well.

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.

Experimental research on process stability in pulsed electrochemical machining of deep narrow grooves with high length-width ratio

With respect to deep narrow groove structures with high length-width ratio and high depth-width ratio (particularly when the ratio is greater than 10), the cathode rigidity and flow-field stability deteriorate during the electrochemical machining (ECM) process. To improve the machining efficiency and process stability of deep narrow grooves with high length-width ratio, a hollow slice cathode with stiffeners was designed and optimized to meet the rigid requirements using the method of one-way fluid-solid coupling finite element analysis. Additionally, the effects of cathode stiffener size, stiffener distribution, and cathode vibrating feed mode on the flow field in the machining gap were investigated using the flow-field simulation analysis method. The simulation results indicate that cavitation and electrolyte starvation in the machining gap are avoided with a reasonable stiffener design, and the renewal of electrolyte in the machining gap is improved with a reasonable vibration motion. Contrast experiments were performed based on the simulation results. The experimental results verified that the optimal design of stiffeners and the reasonable cathode vibration improve the stability of the flow field. Moreover, process stability and machining efficiency of ECM of deep narrow grooves with high length-width ratio improve with the adoption of the optimal vibrating feed parameters.

Electro-chemical spark machining–based hybrid machining processes: Research trends and opportunities

Shaping of the difficult-to-machine non-conductive materials such as glass, quartz and ceramic is much difficult and uneconomical by existing machining processes. As a result, wide applicabilities of these materials are still limited. Even though these materials are highly required in the field of the modern industries. To overcome the problem, a new machining method has been proposed by researchers by combining the features of electro-chemical machining and electro-discharge machining. Such combined machining process is called as electro-chemical spark machining process. Such developed machining method becomes an appropriate process for machining of non-conductive materials with significant improvement in productivity as compared to the electro-discharge machining and electro-chemical machining processes. In this article, the role of electro-chemical spark machining for machining of the non-conductive materials has been summarized and focused on the future research possibilities in the same area. This article also focuses on mechanism, process and performance parameters, variants and new developments related to the electro-chemical spark machining. As a result, this review article becomes beneficial for researchers to understand the phenomena of the electro-chemical spark machining process as well as further development in the same area.

Controlled Phase Interactions Between Pulsed Electric Fields, Ultrasonic Motion, and Magnetic Fields in an Anodic Dissolution Cell

This paper presents the design of a novel testbed that effectively combines pulsed electric field waveforms, ultrasonic velocity, and magnetic field waveforms in an anodic dissolution electrochemical machining (ECM) cell. The testbed consists of a custom three-dimensional (3D)-printed flow cell that is integrated with (i) a bipolar-pulsed ECM circuit, (ii) an ultrasonic transducer, and (iii) a custom-built high-frequency electromagnet. The driving voltages of the ultrasonic transducer and electromagnet are calibrated to achieve a timed workpiece velocity and magnetic field, respectively, in the machining area. The ECM studies conducted using this testbed reveal that phase-controlled waveform interactions between the three assistances affect both the material removal rate (MRR) and surface roughness (Ra) performance metrics. The triad-assisted ECM case involving phase-specific combinations of all three high-frequency (15.625 kHz) assistance waveforms is found to be capable of achieving a 52% increase in MRR while also simultaneously yielding a 78% improvement in the Ra value over the baseline pulsed-ECM case. This result is encouraging because assisted ECM processes reported in the literature typically improve only one of these performance metrics at the expense of the other. In general, the findings reported in this paper are expected to enable the realization of multifield assisted ECM testbeds using phase-specific input waveforms that change on-the-fly to yield preferential combinations of MRR and surface finish.

Review Paper on ECM, PECM and Ultrasonic Assisted PECM

This paper deals with overview of electrochemical machining process along with its principles. It is also focused on the literature survey to discuss various advantages, disadvantages and applications of ECM, PECM and Ultrasonic assisted PECM. Electrochemical and Pulse electro chemical machining processes have gained importance as major electro-machining processes with unique capabilities. These machining process offer a better alternative or sometimes the only alternative in generating accurate 3-D complex shaped macro, micro and Nano features and components of difficult–to-machine materials. Technological advances reported in ultrasonic assisted pulse electrochemical process, which reflect the state of the art in academic and industrial research and applications, are briefly reviewed in this paper.

Machining of Small Curved Hole Using Electrochemical Machining Process

This paper describes the optimization of the tool design and machining condition in a small curved hole machining method. Curved holes can be machined using a flexible tool which can be curved by the hole being processed by the tool itself. The curvature of the hole can be determined by the tilt angle of the electrode tip attached to the end of the tool, and by the feed speed of the electrode. The experiments carried out using electrochemical machining showed that the proposed method could produce smooth curved holes without any special control. It was demonstrated that complicated curved holes with various curvatures were also produced successfully. These experimental results exhibited that the proposed method had a high potential as a processing method for curved holes in a metal mold. But, when this method was applied to small curved holes less than 6mm in diameter, it became clear that long time was necessary. In order to reduce this machining time, massive sludge has to be removed from the machining area effectively. A tool electrode device equipped with ultrasonic vibration function was designed and fabricated, for removal of the sludge from the bending cooling channel during machining. In consideration of an application to metal molds, it was found that a electrochemical machining attached ultrasonic vibration could reduce machining time of curved holes.

Investigation on Hybrid Mechano-electrochemical Milling of Ti6Al4V

To satisfy the increasing demand for processing high-performance materials in industry, a new hybrid process, Mechano-Electrochemical Milling (MECM), is developed in this research. This hybrid machining process combines the effect of both the conventional milling process and the Electrochemical Machining process (ECM). The principle of this process will be depicted in this paper. To present the effectiveness of the developed process, experiments have been carried out on Ti6Al4V. A comparative study for ECM and MECM concerning material removal rate and shape accuracy will be presented. Further, the material removal mechanism and surface quality of the new process were investigated.

Investigation of Influence Factors of Surface Roughness at Corner Area in ECM Process

Surface quality of workpiece with sudden dimension change processed by electrochemical machining (ECM) is affected by many factors, such as the electrolyte flow pattern, gap between tool and workpiece electrodes, machining by-products such as gas bubbles, etc. In this paper, surface polishing process of a workpiece with sudden dimension change was considered. The electrolyte flow velocity distribution and vortex formed due to the sudden dimension change was discussed. Then, the transport of gas bubbles by the flow and its effect on the current density distribution in the electrolyte as well as the effect of current density distribution on the generation of bubbles were also investigated. Results show that current distribution on the electrode surface was greatly affected by the generation and accumulation of gas bubbles around the corner area due to the sudden dimension change of flow channel geometry, which leads to poor surface quality near the workpiece corner.

Experimental Research on Improving ECM Accuracy and Stability for Diamond-hole Grilles

The demand for high-quality diamond-hole grilles, characterized by a voluminous and closely spaced array distribution of holes, has stretched traditional machining to the limit. For this reason, electrochemical machining is considered to be one of the better processing technologies for diamond grid holes. In order to improve the accuracy of electrochemical machining (ECM) for diamond-hole grilles, factors affecting the ECM process based on the electrochemical anodic dissolution theory were investigated in this study. The importance of small-gap processing for achieving higher machining accuracy was highlighted. In small-gap processing of diamond holes, the ECM mode was optimized using cathode side insulation, pulse power supply, passivating electrolyte, and other measures. A test-based comparative analysis of two differing machining modes, i.e., composite-feed ECM mode and precise ECM mode, was performed. The results showed that precise ECM mode, which precisely synchronizes the composite feed vibration with the pulse power supply, offered better machining accuracy and process stability in the ECM process for diamond-hole grilles. Precise ECM mode is envisaged to play a prominent role in the development of ECM technology.

Flow Field Design and Experiments on Pulse ECM of Large-lead Ball Nut Raceway During Tool Cutting-out Stage

A novel process of pulse electrochemical machining (PECM) using a spherical tool cathode with inner slant jet has been proposed and preliminary verified for the machining of large-lead ball nut raceway, in which the electrolyte flow field uniformity plays a very important role in achieving high machining accuracy and process stability. This paper is focusing on the flow field design during tool cutting-out stage, which is considered necessity for realizing one-pass PECM of raceway. Difficulties of flow field design lie in the nonuniform flow field distribution caused by the sudden change of electrolyte flow and the possible deformation or movement of the spike. The method using sacrifice metal was adopted and two novel types of fastening way (the welding type and the magnetic attraction type) were presented to solve the problems existing in conventional methods using sacrifice metal. Verification experiments were conducted and the results show that stable PECM can be achieved using these two types of method. It's also found that the magnetic attraction type of method has better performance of process stability and adaptability than that of the welding type.

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.

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.

Hole drilling and milling of magnetic alloys parts by shaped tube electrolytic machining

In this research shaped tube electrolytic machining of drilling and milling of magnetic alloys parts and difficult-to-cut metals, steels and alloys is presented. New research made in the field of space, aviation, automobile, medical, computer and electronics, and others has created the need for small and fine holes with high aspect ratio in these materials. The primary investigations of ECM with the tubular tool electrode are presented. Compared with mechanical machining, shaped tube electrolytic machining (STEM) exhibits an advantage in producing micro-holes with a high aspect ratio and in producing the curved holes. In order to realize the process of electrochemical machining, experimental assembly with the shaped tube tool electrode has been designed and manufactured. Completed researches indicate that this tool electrode has a high potential to machine difficult-to-cut and brittle metals economically and efficiently.

Modeling and Simulation of the Microstructure Evolution of 42CrMo4 Steel During Electrochemical Machining

Machining independently of mechanical material properties like hardness or high temperature strength is one mayor advantage of the electrochemical machining process (ECM). Additionally, high material removal rates can be achieved in combination with best surface integrities. Nevertheless, one limiting factor in the resulting surface integrity can be a significantly varying dissolution rate of material phases in a multi phase material during ECM. These differences in the dissolution rates determine the surface topography as well as the achievable surface roughness. However, this behavior cannot be forecasted up to now.For that reason, this paper presents a model for the prediction of the microstructure evolution as well as simulation results regarding the influence of the electrochemical machining process on resulting surface topography for the ferritic perlitic steel 42CrMo4 in a passivating electrolyte system. With the help of the model, the evolution of surface topography can be predicted and will be analyzed for different process parameters and various initial microstructures.

Creating an Electronic Reference and Information Database for Computer-aided ECM Design

The paper presents a review on electrochemical shaping. An algorithm has been developed to implement a computer shaping model applicable to pulse electrochemical machining. For that purpose, the characteristics of pulse current occurring in electrochemical machining of aviation materials have been studied. Based on integrating the experimental results and comprehensive electrochemical machining process data modeling, a subsystem for computer-aided design of electrochemical machining for gas turbine engine blades has been developed; the subsystem was implemented in the Teamcenter PLM system.

Analysis of electrochemical machining process with ultrashort pulses considering stray inductance of pulse power supply

Analysis of electrochemical machining process with ultrashort pulses considering stray inductance of pulse power supply

Experimental Investigations of Cutting Rates and Surface Integrity in Wire Electrochemical Machining with Rotating Electrode

The advantages of ECM regarding productivity and best surface qualities are always challenged by high costs for process development and complex electrolyte flow devices. Combining the working principle of electrochemical machining (ECM) with a universal tool, like a wire, could meet these challenges. Such a wire ECM process might be able to machine flexible and efficient 2.5-dimensional geometries like fir tree slots in turbine discs. Nowadays, established manufacturing technologies for such geometries are broaching and wire electrical discharge machining (wire EDM). Nevertheless, high requirements on surface integrity of turbine parts need an intensive process development and – in case of wire EDM – trim cuts to reduce the heat affected rim zone. In the past, few studies dealt with the development of a wire ECM process to meet these challenges. However, previous concepts of wire ECM were only suitable for micro machining applications. Due to insufficient flushing concepts, the application of the process for machining macro geometries with higher cutting rates failed. Therefore, this paper presents experimental investigations on wire electrochemical machining of macro geometries. An axial flushing approach with a rotating tool electrode is used in order to optimize electrolyte flushing and thus, to increase cutting rates. The influences of different machining parameters on cutting kerf, surface integrity and cutting rate will be presented.

Artificial neural network models for the prediction of MRR in Electro-chemical machining

Electro-chemical machining (ECM) uses a set of intricate process to create a negative image of tool on workpiece by high rate anodic dissolution. A Full factorial (DOE) 24 is applied to determining the most important factors which influence MRR of AA6061 (T6). In the present work, experimental data collected are tested with analysis of variance (ANOVA) and Artificial Neural Network (ANN) model has been proposed for the prediction of response. For this purpose, the MATLAB has been used for training and testing of neural network model. The predicted results using ANN specify good agreement between the predicted values and experimental values. Multilayer perceptron model has been constructed with back-propagation algorithm using four process parameters viz. voltage, feed rate, electrolyte concentration and electrode (Cu, Brass) are considered in this study. Finally, ANN model has been found efficient to predict ECM process response for selected process conditions.

Study on Precision Microholes Using Pulsed Laser with Jet Electrochemical Machining

The precision machining basically in the micron domain is a great challenge for advanced manufacturing industries. The assistance of laser beam with jet electrochemical machining process will localize the machining zone and helps to electrochemical dissolution of metal from the specific area which improves the machining quality and precision. Keeping in view, a hybrid laser-assisted jet electrochemical machine (LA-JECM) has been indigenously developed and utilized for microhole drilling experiments. The assistance of laser beam increases localization effect by increasing and maintaining the temperature in a predominant mode. A low-power Nd:YAG diode-pumped solid-state laser beam of wavelength 532 nm is used concentrically with electrolytic jet and carefully monitored its application; otherwise, electrolyte will start to boil due to supply of high laser beam energy and hamper the precision. The percentage of reduction in taper, overcut and average spark-affected zone are 32.3; 27.8; and 50.2%, respectively, when machining operations were carried out on LA-JECM over jet electrochemical machine. Taguchi method-based design of experiments is employed for experimental investigation, and acquired results are utilized for optimization of LA-JECM parameters for further improvement and precision.