Rotational Speed Of Electrode Research Articles

Simultaneous parametric optimization of micro-EDM drilling of brass C360 using Taguchi based grey relation analysis

Micro-EDM (Electro Discharge Machining) is widely used for precision manufacturing and drilling micro-holes in materials used in fuel nozzles, micro sensors and robots, surgical instruments, turbines etc. Present paper deals with drilling common C360 brass components by micro-machining and optimizing the process parameter using a hybrid approach of design of experiments (DoE) and grey relation analysis (GRA) concept. The three process responses considered are material removal rate (MRR), tool wear rate (TWR) and taper in drilled hole while the four selected controllable process parameters are capacitance(C), voltage(V), feed rate(f) and rotational speed of electrode (N). Significance of input factors on each response is analyzed with the help of a 24 full factorial by conducting 16 experiments at two levels for factors. Optimum levels of robustness for each process response are established through Taguchi’s S/N ratio. A combined grey relation grade is applied to find the process levels conducive for optimizing MRR and TWR simultaneously.

Material removal analysis of hybrid EDM-assisted centrifugal abrasive flow machining process for performance enhancement

Finishing of metallic machine components is a prime requirement for the better performance and longer product life cycle. To get highly finished machine components, a number of conventional and non-conventional finishing processes have evolved in recent times to overcome constraints due to shape and properties of materials. This paper discusses a new hybrid technique, Thermal additive centrifugal abrasive flow machining (TACAFM) which is a combination of centrifugal force-assisted abrasive flow machining and electrical discharge machining (EDM) process. In this process abrasive particles move coaxially with workpiece and also rotate inside the hollow workpiece with the help of a rotating system and also generated thermal effect as in EDM process. Due to the movement of abrasive particles along with rotation, Coriolis effect plays a major role in determining the position of abrasives at any time. Therefore, in the present study, Coriolis component effect is incorporated in the mathematical model to predict the material removal in TACAFM. Also, its parameters, viz current, abrasive concentration, pressure, duty cycle, and rotation of electrode, were optimized using response surface methodology. A simulation model is also presented using Ansys® 15 software to analyze the effect of temperature around the work surface when varying gap between the electrode and work surface along with rotational speed of electrode. Experimental results show a good agreement with the mathematical model. The experiments conducted on the developed process show average 44.34% improvement in material removal and average 39.74% improvement in surface finish, respectively.

An hybrid approach for multi-response optimization of rotary electrical discharge machining of nickel super alloy

Abstract RENE80 nickel super alloy is widely used in aerospace industry and difficult to machine due to its high hardness, high temperature strength and low thermal conductivity and high reactivity with the tools during machining. Hence it can be machined by non-traditional processes like EDM or its variants. In this paper, multi-response optimization of rotary EDM of RENE80 is carried out with copper electrode. ANOVA results indicate that peak current and rotational speed of electrode are significant contributors to various responses. Confirmation experiments showed significant improvements in radial overcut, surface roughness and metal removal rate as 8.73%, 20.82% and 17.93% respectively.

A Study on White Layer Thickness and Surface Crack Density in Rotary EDM of RENE80 Nickel Superalloy

In this paper, rotary electrical discharge machining of RENE 80 nickel super alloy is carried out to study the effect of process parameters like peak current, pulse on time, pulse off time and rotational speed of electrode on surface integrity characteristics like white layer thickness and surface crack density. The number of experiments, optimum levels of the parameters and their effects are studied using Taguchi method. The significant process parameters are identified using analysis of variance. It is found that the responses are affected mainly by peak current and pulse on time. The experimental results reveal that white layer thickness increases with increase of peak current and pulse on time whereas the surface crack density decreases with increase of peak current and pulse on time.

Optimization of Process Parameters on EDM Milling of Stainless Steel AISI 304

Electrical Discharge Machining (EDM) is one of the most widely used non conventional machining processes for removing material from workpiece by means of a series of repeated electric discharges. This process is now one of the main techniques used in die production and has good accuracy and precision with no direct physical contact between the electrodes so that no mechanical stress is exerted on the workpiece. Electrical discharge milling (ED-milling) is an emerging technology where a cylindrical tool electrode follows a programmed path in order to obtain the desired shape of a part. The current investigation aims to optimize the process parameters during EDM milling of stainless steel by using copper electrode. The selected input parameters used for the study are voltage, rotational speed of the electrode and feed rate while the responses are material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (Ra). Response surface methodology is used in the study. The experimental design is formed by using design expert software. Central Composite design (CCD) is used to identify the optimum operating condition in order to obtain maximum MRR, minimum EWR and minimum Ra as response. The result shows that the machining parameter setting of voltage 120 V, rotational speed of electrode 1200 rpm and feed rate 4μm/s, gives optimized responses MRR 5.0259 x 10-3 mm3/min, EWR 53% and Ra 0.79 μm.

Modeling and Analysis of MRR, EWR and Surface Roughness in EDM Milling through Response Surface Methodology

Problem statement: Electrical Discharge Machining (EDM) has grown over the last few decades from a novelty to a mainstream manufacturing process. Though, EDM process is very demanding but the mechanism of the process is complex and far from completely understood. It is difficult to establish a model that can accurately predict the performance by correlating the process parameters. The optimum processing parameters are essential to increase the production rate and decrease the machining time, since the materials, w hich are processed by EDM and even the process is very costly. This research establishes empirical re lations regarding machining parameters and the responses in analyzing the machinability of the sta inless steel. Approach: The machining factors used are voltage, rotational speed of electrode and feed rate over the responses MRR, EWR and Ra. Response surface methodology was used to investigate the relationships and parametric interactions between the three controllable variables on the MRR , EWR and Ra. Central composite experimental design was used to estimate the model coefficients of the three factors. The responses were modeled using a response surface model based on experimental results. The significant coefficients were obtained by performing Analysis Of Variance (ANOVA) at 95% level of significance. Results: The variation in percentage errors for developed models was found within 5%. Conclusion: The developed models show that voltage and rotary motion of elect rode are the most significant machining parameters influencing MRR, EWR and Ra. These models can be used to get the desired responses within the experimental range.

Pulse electrochemical finishing: Modeling and experiment

Surface quality of the workpiece has great influence on its service performance and lifespan. Pulse electrochemical finishing (PECF) provides an effective method for improving surface quality of the workpiece. In PECF, surface irregularities are removed by electrochemical dissolution rather than by cutting force. Due to non-contact nature of the process, there is no residual stress and thermal effect on the workpiece surface. For successful utilization of PECF, in present manufacturing, it still demands for more intensive research, including the mechanism of anodic smoothing. The anodic smoothing characteristics of PECF are analyzed through a developed mathematical model. The main influencing factors such as the finishing time, the interelectrode gap, the applied voltage and the rotational speed of electrode have been examined. The predictive values based on the developed mathematical model are found to be in reasonable agreement with the experimental values. The surface roughness Rz ranges from 3 μm to 1.22 μm. The research achievement through various parametric studies can be used as a guideline for the operation of a PECF system.

Design of rib plate of electrode in electrochemical smoothing and electrobrightening of large hole

This study discusses the improvement of surface finish of medium or large holes beyond traditional drilling, boring, rough turning, or extruding by electrochemical smoothing using inserted rib-plate electrodes. High electrical current is not required when the rib plate is used to reduce the engaged area for large hole. Traditionally, the hole polishing requires a sequence of complicated premachining or scarce manual skill. In the current experiment, six types of electrode are completely inserted and connected to both continuous and pulsed direct currents. The controlled factors include the chemical composition and the concentration of the electrolyte, and the diameter of the electrode. The experimental parameters are the current density, on/off period of pulsed current, rotational speed of electrode, and the electrode geometry. For the inserted electrodes, a thin rib plate with small wedge angle towards the root of the plate provides more sufficient discharge space, which is advantageous for polishing. The electrode of single plate performs better than the double-plate electrode. The electrode of a single plate with slant discharge flute performs the best polishing effect. Pulsed direct current can slightly improve the polishing effect at the expense of increased machining time and cost. It was also found that electrobrightening after reaming or precise turning uses quite a short time to make the hole bright, and the electrochemical smoothing saves the need for reaming or precise turning, making the total process time less than the electrobrightening.

Feasibility study of rotary electrical discharge machining with ball burnishing for Al 2O 3/6061Al composite

This study investigates the feasibility and optimization of a rotary EDM with ball burnishing for inspecting the machinability of Al 2O 3/6061Al composite using the Taguchi method. Three ZrO 2 balls attached as additional components behind the electrode tool offer immediate burnishing following EDM. Three observed values (machining rate, surface roughness and improvement of surface roughness) are adopted to verify the optimization of the machining technique. In addition, six independent parameters are chosen as variables for evaluating the Taguchi method; these variables are categorized into two groups: (1) electrical parameters, i.e. peak current, pulse duration and non-load voltage; and (2) non-electrical parameters, i.e. flushing pressure of dielectric, rotational speed of electrode and residual height of hump. Experimental results indicated a feasible technique for applying rotary EDM with ball burnishing in machining the Al 2O 3/6061 composite. Optimization of this technique is also discussed.

Electrode kinetics of oxygen reduction: A theoretical and experimental analysis of the rotating ring-disc electrode method

The previous theoretical treatments of the rotating ring-disc electrode method to distinguish between the mechanisms of electroreduction of O 2 to H 2O with and without the formation of H 2O 2 as an intermediate, were examined. A new expression was derived for I d1/( I d1− I d) as a function of ω −1/2 (where I d1 is the disc limiting current, I d is the disc current and ω is the rotational speed of electrode) for five possible reaction models. This, along with the corresponding expressions for I d/ I r vs. ω −1/2 ( I r is the ring current), enables the calculations of the individual rate constants for the intermediate steps of O 2 reduction. The experimental data of I d and I r were obtained for O 2 reduction on platinum in 0.55 M H 2SO 4 at 25°C. By use of these experimental results in the present theoretical treatment, it is shown that: (1) the most applicable model over the entire potential region was the one suggested by Damjanovic, Genshaw and Bockris; (2) the models involving the adsorption/desorption of H 2O 2 were applicable only over a narrow region of potential; and (3) the models involving the chemical decomposition of H 2O 2 were inconsistent with the dependence of I d1/( I d1− I d) vs. ω −1/2.