Influence of Process Parameters on Characteristics of Electrical Discharge Machining of PH17-4 Stainless Steel

2015 ◽  
Vol 14 (03) ◽  
pp. 189-202 ◽  
Author(s):  
V. Vikram Reddy ◽  
P. Madar Valli ◽  
A. Kumar ◽  
Ch. Sridhar Reddy

In the present work, an investigation has been made into the electrical discharge machining process during machining of precipitation hardening stainless steel PH17-4. Taguchi method is used to formulate the experimental layout, to analyze the effect of each process parameter on machining characteristics and to predict the optimal choice for each electrical discharge machining process parameters namely, peak current, pulse on time and pulse off time that give up optimal process performance characteristics such as material removal rate, surface roughness, tool wear rate and surface hardness. To identify the significance of parameters on measured response, the analysis of variance has been done. It is found that parameters peak current and pulse on time have the significant affect on material removal rate, surface roughness, tool wear rate and surface hardness. However, parameter pulse off time has significant affect on material removal rate. Confirmation tests are conducted at their respective optimum parametric settings to verify the predicted optimal values of performance characteristics.

Author(s):  
G. Ramanan ◽  
R. Elangovan

In aerospace and automobile industries manufacturing complex structures using un-conventional machining is increased due to their precision and accuracy. This research investigates the influence of input parameters such as discharge current, pulse on time, pulse off time and servo speed rate of wire cut electrical discharge machining (WEDM) on material removal rate and surface roughness using Box Behnken design supported with response surface methodology. Aluminium alloy 7075 reinforced with 9 % wt. of activated carbon composite is used to carry out the machining process. Most influencing parameters are subjected as the conductive and non-conductive parameters in WEDM process. To find out the significant influence of each factor, analysis of variance was performed. The mathematical model is established using desirability technique and then the optimal machining parameters are determined. The best achieved WEDM performances - material removal rate and surface roughness are 10.46 mm3/min and 3.32μm respectively, by using optimum machining conditions - discharge current 2000mA, pulse on time 8.9µs, pulse off time 25µs and servo speed rate 150rpm at 0.8597 desirability value.


Author(s):  
R Rajeswari ◽  
MS Shunmugam

Electrical discharge machining is used in the machining of complicated shapes in hardened molds and dies. In rough die-sinking stage, attempts are made to enhance material removal rate with a consequential reduction in cycle time. Powder mix and ultrasonic assistance are employed in the electrical discharge machining process to create gap conditions favoring material removal. In the present work, experiments are carried out on hardened D3 die steel using full-factorial design based on three levels of voltage, current and pulse on time. The gap phenomena in graphite powder-mixed and ultrasonic-assisted rough electrical discharge machining are studied using a detailed analysis of pulse shapes and their characteristic trains. Two new parameters, namely, energy expended over a second ( E) and performance factor ( PF) denoting the ratio of energy associated with sparks to total discharge energy, bring out gap conditions effectively. In comparison with the conventional electrical discharge machining for the selected condition, it is seen that the graphite powder mixed in the dielectric enhances the material removal rate by 20.8% with E of 215 J and PF of 0.227, while these values are 179.8 J and 0.076 for ultrasonic-assisted electrical discharge machining with marginal reduction of 3.9%. Cross-sectional images of workpieces also reveal the influence of electrical discharge machining conditions on the machined surface. The proposed approach can be extended to different powder mix and ultrasonic conditions to identify condition favoring higher material removal.


Author(s):  
Sadananda Chakraborty ◽  
Souren Mitra ◽  
Dipankar Bose

Precision machining characteristics with high-dimensional accuracy make the material more adaptable towards the applications. The present study employs the powder mixed wire electrical discharge machining process to machine Ti6Al4V alloy material. In spite of limited drawbacks and enhanced output in the powder mixed wire electrical discharge machining process, the present problem has been formulated for improving the machining efficiency of Ti6Al4V. The impact of suspended powder characteristics on responses, that is, material removal rate and surface roughness, is examined throughout the process. The current investigation also focuses on the interaction effect of machining constraints along with Al2O3 abrasive mixed dielectric to achieve economical machining output for the Ti6Al4V material. An effort has been presented to obtain optimal solutions using the different methodologies, namely response surface methodology, grey relation analysis, and particle swarm optimization. The study reveals that discharge energy is deeply influenced by the peak current and pulse off time followed by powder concentration in the powder mixed wire electrical discharge machining process. The maximum material removal rate of 6.628 mm3/min and average surface finish of 1.386 μm are the outcome of the present study for a set of optimal machining settings, that is, pulse off time ( Toff) of 7.247 μs, pulse on time ( Ton) of 30 μs, peak current ( Ip) of 2 A, and powder concentration of 4 g/L. Finally, the proposed model has been verified that the hybrid particle swarm optimization technique has the highest adequate capability to achieve maximum output. Thus, the approach offered an enhancement on performance measures of Ti6Al4V alloy in the powder mixed wire electrical discharge machining process.


2015 ◽  
Vol 787 ◽  
pp. 366-370 ◽  
Author(s):  
Vaibhav Gaikwad ◽  
Vijaykumar S. Jatti ◽  
T.P. Singh

NiTi alloys possess superior material properties such as high specific strength, high corrosion resistance, high wear resistance and high anti-fatigue property. Due to these properties it is difficult to machine these alloys using conventional machining process. Nowadays non-conventional machining processes are widely used for machining such adavanced materials. Electrical Discharge machining (EDM) is one such non-conventional process, which can machine electrically conductive materials of any hardness values. Present study aims at drilling mesoscale 3 mm square holes on NiTi alloy by varying the electrical parameters namely, gap current, pulse on time and pulse off time. Additional, the present work includes finding out the effect of cryogenic treatment of NiTi work material on electrical discharge machining performance measures namely material removal rate (MRR) and tool wear rate (TWR). Based on experiments conducted, it can be concluded that with increase in current both material removal rate and tool wear rate increases. It is also noted that cryo-treatment of workpiece material improves MRR with respect to gap current. Similarly there is an increase in MRR with respect to pulse on time and pulse off time for cryo-treated workpiece material. There is a slight improvement of TWR with respect to gap current, pulse on time and pulse off time for cryo-treated workpiece material.


Author(s):  
Gurpreet Singh ◽  
DR Prajapati ◽  
PS Satsangi

The micro-electrical discharge machining process is hindered by low material removal rate and low surface quality, which bound its capability. The assistance of ultrasonic vibration and magnetic pulling force in micro-electrical discharge machining helps to overcome this limitation and increase the stability of the machining process. In the present research, an attempt has been made on Taguchi based GRA optimization for µEDM assisted with ultrasonic vibration and magnetic pulling force while µEDM of SKD-5 die steel with the tubular copper electrode. The process parameters such as ultrasonic vibration, magnetic pulling force, tool rotation, energy and feed rate have been chosen as process variables. Material removal rate and taper of the feature have been selected as response measures. From the experimental study, it has been found that response output measures have been significantly improved by 18% as compared to non assisted µEDM. The best optimal combination of input parameters for improved performance measures were recorded as machining with ultrasonic vibration (U1), 0.25 kgf of magnetic pulling force (M1), 600 rpm of tool rotation (R2), 3.38 mJ of energy (E3) and 1.5 mm/min of Tool feed rate (F3). The confirmation trail was also carried out for the validation of the results attained by Grey Relational Analysis and confirmed that there is a substantial improvement with both assistance applied simultaneously.


2012 ◽  
Vol 488-489 ◽  
pp. 871-875
Author(s):  
V. Anandakrishnan ◽  
V. Senthilkumar

Copper based metal matrix composite reinforced with Boron Carbide is a newly developed Electrical Discharge Machining (EDM) electrode showing better performance than the conventional copper based electrode. Right selection of machining parameters such as current, pulse on time and pulse off time is one of the most important aspects in EDM. In this paper an attempt has been made to develop mathematical models for relating the Material Removal Rate (MRR), Tool Removal Rate (TRR) and Surface roughness (Ra) to machining parameters (current, pulse-on time and pulse-off time). Furthermore, a study was carried out to analyze thSubscript texte effects of machining parameters on various performance parameters such as, MRR, TRR and Ra. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models, can adequately describe the performance within the limits of the factors being studied. Response surface modeling is used to develop surface and contour graphs to analyze the effects of EDM input parameters on outer parameters.


2020 ◽  
Vol 10 (1) ◽  
pp. 401-407
Author(s):  
Yanuar Rohmat Aji Pradana ◽  
Aldi Ferara ◽  
Aminnudin Aminnudin ◽  
Wahono Wahono ◽  
Jason Shian-Ching Jang

AbstractThe machinability information of Zr-based bulk metallic glasses (BMGs) are recently limited but essential to provide technological recommendation for the fabrication of the medical devices due to the material’s metastable nature. This study aims to investigate the material removal rate (MRR) and surface roughness under different current and pulse-on time of newly developed Ni- and Cu-free Zr-based BMG using sinking-electrical discharge machining (EDM). By using weightloss calculation, surface roughness test and scanning electron microscopy (SEM) observation on the workpiece after machining, both MRR and surface roughness were obtained to be increased up to 0.594 mm3/min and 5.50 μm, respectively, when the higher current was applied. On the other hand, the longer pulse-on time shifted the Ra into the higher value but lower the MRR value to only 0.183 mm3/min at 150 μs. Contrary, the surface hardness value was enhanced by both higher current and pulse-on time applied during machining indicating different level of structural change after high-temperature spark exposure on the BMG surface. These phenomena are strongly related to the surface evaporation which characterize the formation of crater and recast layer in various thicknesses and morphologies as well as the crystallization under the different discharge energy and exposure time.


In the present work, the effect of process parameters on material removal rate during the machining of aluminium alloy (5086) with WEDM is studied. The four control parameter were selected i.e pulse on time (TON), pulse off time (TOFF), peak current (IP), and spark gap voltage (SV) to investigate their effects on material removal rate (MRR). Each control parameter had three levels. Total 27 experiments were done with a zinc coated brass wire of diameter 0.25 mm. Taguchi L9 orthogonal array technique was used for the experiment. ANOVA was used to find out the significance of control parameters and their contribution on MRR. It was found that maximum material removal rate was 41.52 mm3 /min which was due to high pulse on time and low pulse off time.


Author(s):  
Arun Kumar Rouniyar ◽  
Pragya Shandilya

Magnetic field assisted powder mixed electrical discharge machining is a hybrid machining process with suitable modification in electrical discharge machining combining the use of magnetic field and fine powder in the dielectric fluid. Aluminum 6061 alloy has found highly significance for the advanced industries like automotive, aerospace, electrical, marine, food processing and chemical due to good corrosion resistance, high strength-to-weight ratio, ease of weldability. In this present work, magnetic field assisted powder mixed electrical discharge machining setup was fabricated and experiments were performed using one factor at a time approach for aluminum 6061 alloy. The individual effect of machining parameters namely, peak current, pulse on time, pulse off time, powder concentration and magnetic field on material removal rate and tool wear rate was investigated. The effect of peak current was found to be dominant on material removal rate and tool wear rate followed by pulse on time, powder concentration and magnetic field. Increase in material removal rate and tool wear rate was observed with increase in peak current, pulse on time and a decrease in pulse off time, whereas, for material removal rate increases and tool wear rate decreases up to the certain value and follow the reverse trend with an increase in powder concentration. Material removal rate was increased and tool wear rate was decreased with increase in magnetic field.


2020 ◽  
Vol 861 ◽  
pp. 129-135 ◽  
Author(s):  
Manh Cuong Nguyen ◽  
Luu Anh Tung ◽  
Bui Thanh Danh ◽  
Nguyen Van Cuong ◽  
Tran Thi Hong ◽  
...  

This work is done to determine the effects of the input factors of powder mixed electrical discharge machining (PMEDM) process on the material removal rate (MRR). In the study, the workpiece is cylindrical parts made from 90CrSi alloy steel. Also, five factors containing the pulse on time Ton, the powder concentration Cp, the pulse off time Toff, the pulse current IP, and the server voltage SV were discovered to find their impact on MRR. In addition, the Taguchi method and ANOVA analysis were used to design experiment and analyze the results. In addition, an optimal model of the MRR was introduced. Also, the model has been well verified by comparison with testing, and so it can be used for further studies in the PMEDM process.


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