Investigation on material removal rate, surface and subsurface characteristics in wire electro discharge machining of Ti50Ni50-xCux shape memory alloy

2015 ◽  
Vol 232 (2) ◽  
pp. 164-177 ◽  
Author(s):  
M Manjaiah ◽  
S Narendranath ◽  
S Basavarajappa ◽  
VN Gaitonde
Keyword(s):  
Shape Memory ◽  
Layer Thickness ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Recast Layer ◽  
Phase Changes ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time

TiNiCu shape memory alloys have superior properties as compared with NITINOL due to their greater ductility, reduced hysteresis temperature range, and quick actuation response. The present article investigates the surface and subsurface modifications occurring due to wire electro discharge machining of Ti50Ni50-xCux shape memory alloy. The machining experiments were performed considering the pulse on time, pulse off time, and servo voltage as the process parameters. The influence of these parameters was studied on the material removal rate, surface roughness, recast layer thickness, microhardness, and phase changes in the machined surface. Longer pulse on time causes greater discharge energy, hence leading to higher material removal rate, surface roughness, and recast layer thickness. The machined surface hardness increased up to 900 Hv, which is about 59% increase with respect to the base material for longer pulse on time due to the recast layer thickness and the formation of oxides. A phase change on the machined surface was observed to cause the shape recoverability of the alloy. The microstructure, composition through EDAX, and the phase changes of the machined surface are also discussed in the article.

Comparative evaluation of powder-mixed and ultrasonic-assisted rough die-sinking electrical discharge machining based on pulse characteristics

2019 ◽  
Vol 233 (14) ◽  
pp. 2515-2530 ◽  
Author(s):  
R Rajeswari ◽  
MS Shunmugam
Keyword(s):  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Graphite Powder ◽  
Machining Process ◽  
Machined Surface ◽  
Ultrasonic Assisted ◽  
Pulse On Time

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.

Enhancement of machining and surface quality of quaternary alloyed NiTiCuZr shape memory alloy through ultrasonic vibration coupled WEDM

2021 ◽  
pp. 146442072110582
Author(s):  
C Balasubramaniyan ◽  
K Rajkumar ◽  
S Santosh
Keyword(s):  
Surface Roughness ◽  
Shape Memory ◽  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Ultrasonic Frequency ◽  
Machining Parameters ◽  
Pulse On Time ◽  
Pulse Off Time

NiTiCuZr shape memory alloys (SMA) outperform ternary and binary SMA alloys in terms of functional fatigue and higher temperature performance due to their high cyclic stability and transformation temperatures. Owing to the impairment of the shape memory effect during processing, it is difficult to select a manufacturing process for obtaining design functionality with the required dimensions and surface roughness. In this work, a high-temperature NiTiCuZr SMA was machined using an ultrasonic vibration assisted wire electric discharge machine (USV-WEDM). The machining was conducted using various parameters with a constant ultrasonic vibration of 20 kHz provided on a wire-electrode to evaluate surface roughness (Ra) and material removal rate (MRR). Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray analysis (EDX) were utilized to examine the surface integrity and chemical composition of the machined surfaces. MRR increased by 62% with a steady increase in pulse-on time ( Ton) and applied current ( I), whereas increasing levels of parameters such as pulse-off time ( Toff) and servo voltage (SV) reduced surface roughness ( Ra) by 69%. The results reveal that tool vibration at ultrasonic frequency reduces the surface roughness and improves the material removal rate of the machined NiTiCuZr SMA as compared to that of non-ultrasonic assisted machining conditions. SEM-EDX investigation reveals that the formation of re-solidification and oxide layers during NiTiCuZr machining at high machining parameters results in increased hardness and surface roughness. USV-WEDM is a suitable process for machining SMA alloy without adversely impacting SMA properties.

Modelling of Material Removal Rate in EDM of Nonconductive ZrO2 Ceramic by Taguchi Method

2013 ◽  
Vol 393 ◽  
pp. 246-252 ◽  
Author(s):  
A. Sabur ◽  
Mohammad Yeakub Ali ◽  
M.A. Maleque
Keyword(s):  
Taguchi Method ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Pyrolytic Carbon ◽  
Carbon Layer ◽  
Machining Process ◽  
Machined Surface ◽  
Pulse On Time ◽  
Pulse Off Time

Electro discharge machining (EDM) technique, a noncontact machining process, is applied for structuring nonconductive ZrO2 ceramic. A conductive layer of adhesive copper is applied on the workpiece surface to initiate the sparks. Kerosene is used as dielectric for creation of continuous conductive pyrolytic carbon layer on the machined surface. Experiments are conducted by varying the peak current (Ip), pulse-on time (Ton), pulse-off time (Toff) and gap voltage (Vg). Correlating these variables a mathematical model for material removal rate (MRR) is developed using Taguchi method. The optimized parametric conditions are determined for higher MRR through ANOVA and signal to noise (S/N) ratio analysis. The results showed that the Ip and Ton are the significant parameters of MRR in EDM for nonconductive ZrO2 ceramic. The model also showed that MRR increases with the increase of Ip and Ton, but the process is controlled by Ip as a whole.

EFFECT OF INPUT PARAMETERS ON THE KEY MACHINABILITY ASPECTS OF NITINOL DURING WEDM

2021 ◽  
Author(s):  
HIMADRI MAJUMDER ◽  
ADIK YADAO ◽  
KALIPADA MAITY
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Mechanical Energy ◽  
Phase Changes ◽  
High Tech ◽  
Machined Surface ◽  
Input Parameters ◽  
Pulse On Time

Shape memory alloy (SMA), a distinctive class of material, can possess its preceding form when subjected to definite thermo-mechanical energy. Nitinol, an SMA, having an admirable shape memory effect, super elastic, and biomechanical properties, has developed a vast application in the field of biomedical, automobile, robotics, aerospace, etc. Wire electrical discharge machining (WEDM) technique is employed for machining of electrically conductive materials like SMAs, high tech ceramics, smart materials, etc. This paper is focused on analyzing the effect of different significant input parameters on the vital machinability aspects of SMA nitinol during WEDM. Independent input variables like pulse-on time ([Formula: see text], discharge current ([Formula: see text], wire-speed (WS), wire tension (WT) and flushing pressure (FP) were considered to find out their influence on the kerf width (KW), material removal rate (MRR), arithmetic mean roughness ([Formula: see text], and microhardness ([Formula: see text]h). 3D optical profile, X-ray diffraction analysis, and scanning electron microscopy were also executed on the WEDMed surface to inspect the surface, microstructure, and phase changes in the machined surface. It was detected that [Formula: see text], [Formula: see text] and FP were more influential than WT and WS for most of the responses.

Single Discharge Finite Element Simulation of EDM Process

2015 ◽  
Vol 14 (02) ◽  
pp. 75-89 ◽  
Author(s):  
Rohit Rajendran ◽  
S. P. Vendan
Keyword(s):  
Finite Element ◽  
Material Removal Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Machining Process ◽  
Workpiece Material ◽  
Machined Surface ◽  
Input Parameters ◽  
Pulse On Time ◽  
Aisi H13 Tool Steel

The energy distribution in the electric discharge machining process influences the material removal rate, relative wear ratio and the surface roughness of the machined surface and the effective energy is the part of energy which is distributed toward workpiece to be machined. The theoretical modeling of the process is based upon the heat transfer equations and one of the important parameter is fraction of energy transferred to the workpiece. The model first calculates the temperature distribution in the workpiece material using ANSYS Finite element coding and then volume removed due to single spark is estimated from the temperature profiles. Theoretical material removal rate at different input parameters are compared with the experimental results, making it possible to determine the portion of energy that enters AISI H13 tool steel workpiece. The effect of input parameters (discharge current, voltage, pulse on time) on temperature distributions along the radius and depth of the workpiece has been reported.

Machining performance of cryogenically treated Ti–5Al–2.5Sn titanium alloy in electric discharge machining: A comparative study

2016 ◽  
Vol 231 (11) ◽  
pp. 2017-2024 ◽  
Author(s):  
Sanjeev Kumar ◽  
Ajay Batish ◽  
Rupinder Singh ◽  
TP Singh
Keyword(s):  
Titanium Alloy ◽  
Material Removal Rate ◽  
Electric Discharge ◽  
Material Removal ◽  
Removal Rate ◽  
Cryogenic Treatment ◽  
Machining Performance ◽  
Electric Discharge Machining ◽  
Machined Surface ◽  
Pulse On Time

In the present study, the effect of cryogenic treatment on the machining performance of Ti–5Al–2.5Sn alpha titanium alloy was investigated during electric discharge machining. Untreated, shallow cryogenically treated (−110 ℃), and deep cryogenically treated (−184 ℃) titanium alloys were machined by varying current and pulse-on-time. The machining performance was measured in terms of higher material removal rate and microhardness and low tool wear rate and surface roughness. The results showed a significant improvement in the machining performance with deep cryogenically treated alloy when compared with shallow and untreated alloy. Current and pulse-on-time also affected the machinability of titanium alloy. Higher material removal rate and microhardness were observed when titanium alloy was machined at high current and pulse-on-time. During machining, carbon was deposited on the machined surface due to the breakdown of hydrocarbon dielectric at high temperature thereby, affecting its properties.

Enhancement of EDM Performance by Using Copper-Silver Composite Electrode

2020 ◽  
Vol 38 (9A) ◽  
pp. 1352-1358
Author(s):  
Saad K. Shather ◽  
Abbas A. Ibrahim ◽  
Zainab H. Mohsein ◽  
Omar H. Hassoon
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Material Removal ◽  
High Speed ◽  
Composite Electrode ◽  
Removal Rate ◽  
Pure Copper ◽  
High Speed Steel ◽  
Pulse On Time ◽  
Pulse Off Time

Discharge Machining is a non-traditional machining technique and usually applied for hard metals and complex shapes that difficult to machining in the traditional cutting process. This process depends on different parameters that can affect the material removal rate and surface roughness. The electrode material is one of the important parameters in Electro –Discharge Machining (EDM). In this paper, the experimental work carried out by using a composite material electrode and the workpiece material from a high-speed steel plate. The cutting conditions: current (10 Amps, 12 Amps, 14 Amps), pulse on time (100 µs, 150 µs, 200 µs), pulse off time 25 µs, casting technique has been carried out to prepare the composite electrodes copper-sliver. The experimental results showed that Copper-Sliver (weight ratio70:30) gives better results than commonly electrode copper, Material Removal Rate (MRR) Copper-Sliver composite electrode reach to 0.225 gm/min higher than the pure Copper electrode. The lower value of the tool wear rate achieved with the composite electrode is 0.0001 gm/min. The surface roughness of the workpiece improved with a composite electrode compared with the pure electrode.

Optimization and surface modification in electrical discharge machining of AA 6061/SiCp composite using Cu–W electrode

2015 ◽  
Vol 231 (3) ◽  
pp. 332-348 ◽  
Author(s):  
Balbir Singh ◽  
Jatinder Kumar ◽  
Sudhir Kumar
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Characteristics ◽  
Electrode Wear ◽  
Material Transfer ◽  
Machined Surface ◽  
Recast Layer Thickness ◽  
Pulse On Time ◽  
Pulse Off Time

This paper presents the experimental investigation on the electro-discharge machining of aluminum alloy 6061 reinforced with SiC particles using sintered Cu–W electrode. Experiments have been designed as per central composite rotatable design, using response surface methodology. Machining characteristics such as material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR) have been investigated under the influence of four electrical process parameters; namely peak current, pulse on time, pulse off time, and gap voltage. The process parameters have been optimized to obtain optimal combination of MRR, EWR, and SR. Further, the influence of sintered Cu–W electrode on surface characteristics has been analyzed with scanning electron microscopy, energy dispersive spectroscopy, and Vicker microhardness tests. The results revealed that all the process parameters significantly affect MRR, EWR, and SR. The machined surface properties are modified as a result of material transfer from the electrode. The recast layer thickness is increased at higher setting of electrical parameters. The hardness across the machined surface is also increased by the use of sintered Cu–W electrode.

scholarly journals The Effect of Discharge Current and Pulse-On Time on Biocompatible Zr-based BMG Sinking-EDM

2020 ◽  
Vol 10 (1) ◽  
pp. 401-407
Author(s):  
Yanuar Rohmat Aji Pradana ◽  
Aldi Ferara ◽  
Aminnudin Aminnudin ◽  
Wahono Wahono ◽  
Jason Shian-Ching Jang
Keyword(s):  
Surface Roughness ◽  
Metallic Glasses ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Surface Hardness ◽  
Recast Layer ◽  
Surface Evaporation ◽  
Pulse On Time

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.

scholarly journals Multi- Response Optimization of Wire EDM Process Parameter on Aluminium Alloy (5086)

2020 ◽  
Vol 10 (1) ◽  
pp. 224-229
Keyword(s):  
Aluminium Alloy ◽  
Material Removal Rate ◽  
Material Removal ◽  
Control Parameter ◽  
Removal Rate ◽  
Response Optimization ◽  
High Pulse ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off 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.

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