Study and optimization of surface roughness parameter during electrical discharge machining of titanium alloy (Ti-6246)

Author(s):  
Abhishek Thakur ◽  
P. Sudhakar Rao ◽  
Mohd. Yunus Khan
2015 ◽  
Vol 760 ◽  
pp. 551-556 ◽  
Author(s):  
Oana Dodun ◽  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Vasile Merticaru ◽  
Gheorghe Nagîţ

Wire electrical discharge machining is a machining method by which parts having various contours could be detached from plate workpieces. The method uses the electrical discharges developed between the workpiece and the wire tool electrode found in an axial motion, when in the work zone a dielectric fluid is recirculated. In order to highlight the influence exerted by some input process factors on the surface roughness parameter Ra in case of a workpiece made of an alloyed steel, a factorial experiment with six independent variables at two variation levels was designed and materialized. As input factors, one used the workpiece thickness, pulse on time, pulse off-time, wire axial tensile force, current intensity average amplitude defined by setting button position and travelling wire electrode speed. By mathematical processing of the experimental results, empirical models were established. Om the base of a power type empirical model, graphical representations aiming to highlight the influence of some input factors on the surface roughness parameter Ra were achieved. The power type empirical model facilitated establishing of order of factors able to exert influence on the surface roughness parameter Ra at wire electrical discharge machining.


2015 ◽  
Vol 809-810 ◽  
pp. 411-416 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Margareta Coteaţă ◽  
Hans Peter Schulze ◽  
Oana Dodun ◽  
Ciprian Mircescu ◽  
...  

In order to obtain small diameter external surfaces by ram electrical discharge machining from plate workpieces, tubular tool electrodes could be used. In such a case, one can appreciate that the obtained surface is a simple concatenation of cavities appeared as a consequence of electrical discharges developed between the asperities existing initially on the active surface of the tool electrode and surface to be machined of the workpiece. The analysis of the surface generation as a consequence of the electrical discharge machining process showed that due to the surface tensions, a leveling phenomenon could be taken into consideration. An experimental study of influence exerted by some input factors on the surface roughness parameter Ra was designed and achieved. One noticed that the increase of the pulse on time, pulse off time and peak current intensity determines an increase of the surface roughness parameter Ra. By mathematical processing of the experimental results, an empirical model type power function was determined. The examination of the machined surface by means of an optical microscope showed the existence of microcavities generated by the electrical discharge, while the material melted and re-solidified was placed as a bordure of the microcavities.


Author(s):  
Ze Yu ◽  
Dunwen Zuo ◽  
Yuli Sun ◽  
Guohua Li ◽  
Xuemei Chen ◽  
...  

To simultaneously optimize the surface quality and machining efficiency of the electrical discharge machining (EDM) processes used to produce titanium alloy quadrilateral group small hole parts, a combined “EDM + AFM” machining technology is proposed in this paper as an efficient and high-quality machining approach. In the proposed method, TC4 titanium alloy is first machined using the EDM process with graphite electrodes and the abrasive flow machining (AFM) process is then used to finish the machined surface. The effects of various electrical parameters on EDM-derived surface quality and improvements in EDM-derived quality under the application of AFM were assessed and, using the final surface roughness as a constraint condition, the effects of various combinations of EDM and “EDM + AFM” on efficiency were studied. The results revealed that the thickness and surface roughness of the superficial recast layer of the TC4 titanium alloy increase with both current and pulse width; in particular, increasing these parameters can increase the surface roughness by two to three grades. Following AFM, the alloy has a more uniform hardness distribution and the surface stress state changes from tensile to compressive stress, indicating that the combined “EDM + AFM” machining scheme can significantly enhance the surface quality of EDM-produced titanium alloy quadrilateral small group holes. The combined scheme achieves a balancing point beyond which increasing the roughness or the number of machining holes enhances either the machining efficiency or the machining surface quality. In the case of typical titanium alloy quadrilateral group small hole parts, the combined machining process can improve the finishing efficiency and total machining efficiency by 71.2% and 25.36%, respectively.


Author(s):  
Murahari Kolli ◽  
Adepu Kumar

Surfactant and graphite powder–assisted electrical discharge machining was proposed and experiments were performed on titanium alloy in this investigation. Analysis was carried out to observe changes in dielectric fluid behaviour, material removal rate, surface roughness, recast layer thickness, surface topography and energy-dispersive X-ray spectroscopy. It was found out that the addition of surfactant to dielectric fluid (electrical discharge machining oil + graphite powder) improved the material removal rate and surface roughness. It was noticed to have reduced the recast layer thickness and agglomeration of graphite and sediment particles. Biface material migrations between the electrode and the workpiece surface were identified, and migration behaviour was powerfully inhibited by the mixing of surfactant. Surfactant added into dielectric fluid played an important role in the discharge gap, which increased the conductivity, and suspended debris particles in dielectric fluid reduced the abnormal discharge conditions of the machine and improved the overall machining efficiency.


2013 ◽  
Vol 683 ◽  
pp. 581-584 ◽  
Author(s):  
Shu Guo Zhao ◽  
Rui Li ◽  
Xiao Min Yao

Due to the excellent characteristics of titanium alloy, was applied to aviation, marine, automotive, metallurgy, medical equipment and other fields. However, some of the characteristics make it machine difficultly, so the range of applications would be limited. In this paper, titanium alloy is cut by wire electrical discharge machining (WEDM) and study the surface finish. The model of surface roughness is established which is based on theoretical analysis. Experimental results were analyzed and optimized by the theory of signal-to-noise ratio and grey relational analysis (GRA) method. The minimal surface roughness is achieved by the optimal results .According to GRA, get the order that is the influence of electric parameters on the surface roughness.


2018 ◽  
Vol 1 (1) ◽  
pp. 27-38
Author(s):  
Jun Qi Tan ◽  
Mohd Yazid Abu

The experimental carried out to aim at the selection of the best condition machining parameter combination for wire electrical discharge machining (WEDM) of titanium alloy (Ti–6Al–4V). By using Design Expert 10 software, a series of experiments were performed by selecting pulse-on time, pulse-off time, servo voltage and peak current as parameters. The responses that considered were cutting speed, material removal rate, sparking gap and surface roughness. Based on ANOVA analysis, the effect from the parameters on the responses was determined. The optimum machining parameters setting for the maximum cutting speed, minimum sparking gap and minimum surface roughness were found by proceed optimization experiment. Then, each optimization response had their own combination setting on WEDM to cut titanium alloy. 3D response surface graph such as dome and bowl shape represent maximum and minimum point for the solutions had shown in the report. Finally, predicted and actual value from the experiment have been calculated for validation.


2009 ◽  
Vol 76-78 ◽  
pp. 613-617 ◽  
Author(s):  
Jian Wu Yu ◽  
Peng Xiao ◽  
Yu Shan Liao ◽  
Min Cheng

Titanium alloy is a kind of typical difficult-to-machine materials. In this study, the surface integrity of titanium alloy Ti-6Al-4V machined by electrical discharge machining (EDM) method are experimentally investigated and analyzed in term of surface roughness, SEM micrographs and microcracks. Effect of discharge energy and material properties on surface integrity are presented in this paper.


Author(s):  
Bruna Michelle de Freitas ◽  
Carlos augusto Henning Laurindo ◽  
Paulo Soares ◽  
Leticia Bemben

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