scholarly journals The Accuracy of Finishing WEDM of Inconel 718 Turbine Disc Fir Tree Slots

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 562
Author(s):  
Jan Burek ◽  
Robert Babiarz ◽  
Jarosław Buk ◽  
Paweł Sułkowicz ◽  
Krzysztof Krupa

Servicing aircraft engines sometimes requires manufacturing only a single piece of a given part. Manufacturing a turbine disc using traditional methods is uneconomical. It is necessary to use a different machining method recommended for small lot production. One of the proposed methods is WEDM (wire electrical discharge machining). The article presents the results of the research on finishing WEDM of Inconel 718 turbine disc fir tree slots. The influence of infeed, mean gap voltage, peak current, pulse off-time, and discharge energy on the shape accuracy, surface roughness, microcracks, and the white layer thickness were determined. Mathematical models were developed based on the DoE (Design of Experiment) analysis. The statistical significance of the models was verified with the ANOVA (Analysis of Variance) test. The machining parameters control methods that allow achieving the required shape accuracy, surface roughness, and surface layer condition were presented. The obtained surface roughness was Ra = 0.84 μm, the shape accuracy of the slot in the normal-to-feed direction was Δd = 0.009 μm, the profile shape accuracy was Δr = 0.033 μm, and the thickness of recast (white) layer was approximately 5 μm.

2014 ◽  
Vol 3 (2) ◽  
pp. 212
Author(s):  
M. Durairaj ◽  
A.K.S. Ansari ◽  
M. H. Gauthamkumar

Wire Electrical Discharge Machining is a manufacturing process whereby a desired shape is obtained using electrical discharges (or) by repetitive spark cycle. Precision and intricate machining are the strengths. Machining parameters tables provided by the machine tool manufacturers often do not meet the operator requirements. Selection of optimum machining and machining parameters combinations is needed for obtaining higher cutting efficiency and accuracy. In this present study, machining is done using Wire-Cut EDM and optimization of surface roughness is done using Taguchis design of experiments. Experimentation was planned as per Taguchis L16 orthogonal array. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, and pulse OFF time and Wire feed. Dielectric fluid pressure, wire speed, wire tension, resistance and cutting length are taken as fixed parameters. Inconel 800 was selected as a work material to conduct the experiments. From experimental results, the surface roughness was determined for each machining performance criteria. Signal to noise ratio was applied to measure the performance characteristics deviating from the actual value. Finally, experimental confirmation was carried out to identify the effectiveness of this proposed method. Keywords: Optimization; Taguchis L-16 Orthogonal Array; Surface Roughness; S/N Ratio.


Mechanik ◽  
2018 ◽  
Vol 91 (10) ◽  
pp. 915-917
Author(s):  
Jan Burek ◽  
Robert Babiarz ◽  
Marcin Płodzień ◽  
Jarosław Buk

The article presents the effect of electrode infeed in finishing machining of disk fir tree slots made of Inconel 718 alloy on shape accuracy and surface roughness in WEDM (wire electrical discharge machining).


Author(s):  
Guisen Wang ◽  
Fuzhu Han ◽  
Liang Zhu

Abstract White layer and residual stress are the main reasons for the decrease in fatigue life of electrical discharge machined samples. Therefore, it is important to research the evolution of the white layer and residual stress in electrical discharge machining and explain the influence mechanism of machining parameters on them. In this study, the surface topography, white layer thickness, and residual stress of electrical discharge machined samples under different processing parameters were evaluated. The results indicated that surface roughness, white layer thickness, and residual stress increased as the discharge current (I) and pulse-on time (ton) increased. However, when the ton was short, the effect of I (≤ 9.8 A) on surface roughness is not very obvious. When the discharge energy is similar, surface roughness is high under high I conditions. When the discharge energy is similar and low, the average thickness of the white layer is thin under the low I. The effect of I on surface residual stress was greater than that of the ton. The I and ton affect the white layer and residual stress by affecting the amount of melting and removal of the materials. These results were demonstrated that the input process of discharge energy has an important influence on residual stress and the white layer. Therefore, under the premise of ensuring the processing requirements, they can be controlled by selecting the appropriate combination of the ton and I to improve the fatigue life of the workpiece.


Author(s):  
Gajanan Kamble ◽  
Dr. N. Lakshamanaswamy ◽  
Gangadhara H S ◽  
Sharon Markus ◽  
N. Rajath

Wire cut electrical discharge machining (WEDM) is a hybrid manufacturing technology which enables machining of all engineering materials. This research article deals with investigation on Optimization of the Process Parameters of the wire cut EDM of Bronze material of dimension (80*80*40) in mm. Material removal rate, Surface roughness and Kerf width were studied against the process parameters such as Pulse on time(TON), Pulse off time (TOFF) and Current(IP). The machining parameters for wire EDM were optimized for achieving the combined objectives. As there are three input parameters 27 experiments is carried out and full factorial is used. Optimized parameters were found using (ANOVA) and the error percentage can be validated and parameter contribution for the Material removal rate (MRR) and Surface roughness were found.


Author(s):  
Vineet Dubey ◽  
Anuj K Sharma ◽  
Balbir Singh

The present study establishes the optimum process condition for additive mixed electrical discharge machining of Al7075–5%B4Cp metal matrix composite by performing experimental investigation. The suspension of chromium particles in a dielectric fluid is used as an additive. The input process parameters selected for experimentation are specifically pulse on-time, gap voltage, pulse off-time and peak current, for analysing their influence on wear of the tool along with surface roughness of the composite. Comparative study of the machined surface is done by analysing microstructures, cracks and recast layers formed at different settings of input parameters using a scanning electron microscope. Rise in amount of current and pulse on-time led to increased height of the recast layer generated on the surface of the machined workpiece. Furthermore, a confirmatory experiment was performed at the optimal setting. The result revealed an error of 5.5% and 7.5% between experimental and predicted value of tool wear rate and 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.


2020 ◽  
Vol 977 ◽  
pp. 12-17
Author(s):  
Thi Hong Tran ◽  
Tien Dung Hoang ◽  
Hong Ky Le ◽  
Thi Tam Do ◽  
Thanh Hien Bui ◽  
...  

This paper presents a study on analysis of influences of the surface roughness in Electrical Discharge Machining 90CrSi tablet shape punches with the use of copper electrode. In this paper, 9 experimental runs were designed and conducted by using Taguchi method. In addition, 4 process parameters including the gap voltage, the pulse current, the pulse on time and the pulse off time were investigated. The influences of these input parameters on the surface roughness were evaluated by analysing variance. Also, from the experimental results, optimum values of the input parameters for getting the minimum surface roughness were proposed.


Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 72 ◽  
Author(s):  
Rafał Świercz ◽  
Dorota Oniszczuk-Świercz ◽  
Tomasz Chmielewski

Electrical discharge machining (EDM) is a modern technology that is widely used in the production of difficult to cut conductive materials. The basic problem of EDM is the stochastic nature of electrical discharges. The optimal selection of machining parameters to achieve micron surface roughness and the recast layer with the maximal possible value of the material removal rate (MRR) is quite challenging. In this paper, we performed an analytical and experimental investigation of the influence of the EDM parameters: Surface integrity and MRR. Response surface methodology (RSM) was used to build empirical models on the influence of the discharge current I, pulse time ton, and the time interval toff, on the surface roughness (Sa), the thickness of the white layer (WL), and the MRR, during the machining of tool steel 55NiCrMoV7. The surface and subsurface integrity were evaluated using an optical microscope and a scanning profilometer. Analysis of variance (ANOVA) was used to establish the statistical significance parameters. The calculated contribution indicated that the discharge current had the most influence (over the 50%) on the Sa, WL, and MRR, followed by the discharge time. The multi-response optimization was carried out using the desirability function for the three cases of EDM: Finishing, semi-finishing, and roughing. The confirmation test showed that maximal errors between the predicted and the obtained values did not exceed 6%.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 303
Author(s):  
Panagiotis Karmiris-Obratański ◽  
Emmanouil L. Papazoglou ◽  
Beata Leszczyńska-Madej ◽  
Krzysztof Zagórski ◽  
Angelos P. Markopoulos

Electrical Discharge Machining (EDM) consists of a non-conventional machining process, which is widely used in modern industry, and especially in machining hard-to-cut materials. By employing EDM, complex shapes and geometries can be produced, with high dimensional accuracy. Titanium alloys, due to their unique inherent properties, are extensively utilized in high end applications. Nevertheless, they suffer from poor machinability, and thus, EDM is commonly employed for their machining. The current study presents an experimental investigation regarding the process of Ti–6Al–4V ELI with high power EDM, using a graphite electrode. Control parameters were the pulse-on current (Ip) and time (Ton), while Machining performances were estimated in terms of Material Removal Rate (MRR), Tool Material Removal Rate (TMRR), and Tool Wear Ratio (TWR). The machined Surface Roughness was calculated according to the Ra and the Rt values, by following the ISO 25178-2 standards. Furthermore, the EDMed surfaces were observed under optical and SEM microscopy, while their cross sections were also studied in order the Average White Layer Thickness (AWLT) and the Heat Affected Zone (HAZ) to be measured. Finally, for the aforementioned indexes, Analysis Of Variance was performed, whilst for the MRR and TMRR, based on the Response Surface Method (RSM), semi-empirical correlations were presented. The scope of the current paper is, through a series of experiments and by employing statistical tools, to present how two main machining parameters, i.e., pulse-on current and time, affect major machining performance indexes and the surface roughness.


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