scholarly journals An Investigation To Achieve a Good Surface Integrity in WEDM of Ti-6242 Super Alloy

Author(s):  
Sonia Ezeddini ◽  
Wajdi Rajhi ◽  
Mohamed Boujelbene ◽  
Emin Bayraktar ◽  
Sahbi Ben Salem

Abstract Ti-6242 is a super alloy which exhibits the best creep resistance among available titanium alloys and is widely used in the manufacture by WEDM of aircraft engine turbomachinery components. However, the final quality of wire EDMed surface is a great challenge as it is affected by various factors that need optimization for surface integrity and machine efficiency improvement. The aim of this study is to investigate the effect of a set of cutting process parameters such as pulse on time (Ton), servo voltage (U), feed rate (S) and flushing pressure (p) on surface roughness (SR) when machining Ti-6242 super alloy by WEDM process using a brass tool electrode and deionized water as a dielectric fluid. WEDM experiments were conducted, and SR (Ra) measurement was carried out using a 3D optical surface roughness-meter (3D–SurfaScan). As a tool to optimize cutting parameters for SR improvement, Taguchi's signal‐to‐noise ratio (S/N) approach was applied using L9 (3^4) orthogonal array and Lower-The-Better (LTB) criteria. Substantially, the findings from current investigation suggest the application of the values 0.9 µs, 100V, 29 mm/min, and 60 bar for Ton, U, S and p cutting parameters, respectively, for producing a good surface finish quality. Percent contributions of the machining parameters on SR (Ra) assessed based on ANOVA analysis are 62.94%, 20.84%, 11.46% and 4.74% for U, S, Ton and p, respectively. Subsequently, accurate predictive model for SR (Ra) is established based on response surface analysis (RSA). The contour plots for SR (Ra) indicate that when flushing pressure p converges to a critical value (80 bar), a poor-quality surface finish is highly expected with the excessive increase in U and S. Electron microscope scanning (SEM) observations have been performed on machined surface for a wide range of cutting parameters to characterize wire EDMed surface of Ti-6242. SEM micrographs indicate that the machined surface acquires a foamy structure and shows white layer and machining-induced damage that the characteristics are highly dependent on cutting parameters. At high servo-voltage, the decrease in pulse on time Ton and feed rate S results in a large decrease in overall machining-induced surface damage. Moreover, for high servo-voltage and feed rate levels, it has been observed that pulse on time could play a role of controlling the surface microcracks density. In fact, the use of a low pulse duration of cut combined with high servo-voltage and feed rate has been shown to inhibit surface microcracks formation giving the material surface a better resistance to cracking than at high pulse duration.

2010 ◽  
Vol 447-448 ◽  
pp. 51-54
Author(s):  
Mohd Fazuri Abdullah ◽  
Muhammad Ilman Hakimi Chua Abdullah ◽  
Abu Bakar Sulong ◽  
Jaharah A. Ghani

The effects of different cutting parameters, insert nose radius, cutting speed and feed rates on the surface quality of the stainless steel to be use in medical application. Stainless steel AISI 316 had been machined with three different nose radiuses (0.4 mm 0.8 mm, and 1.2mm), three different cutting speeds (100, 130, 170 m/min) and feed rates (0.1, 0.125, 0.16 mm/rev) while depth of cut keep constant at (0.4 mm). It is seen that the insert nose radius, feed rates, and cutting speed have different effect on the surface roughness. The minimum average surface roughness (0.225µm) has been measured using the nose radius insert (1.2 mm) at lowest feed rate (0.1 mm/rev). The highest surface roughness (1.838µm) has been measured with nose radius insert (0.4 mm) at highest feed rate (0.16 mm/rev). The analysis of ANOVA showed the cutting speed is not dominant in processing for the fine surface finish compared with feed rate and nose radius. Conclusion, surface roughness is decreasing with decreasing of the feed rate. High nose radius produce better surface finish than small nose radius because of the maximum uncut chip thickness decreases with increase of nose radius.


Author(s):  
Rajkeerthi E ◽  
Hariharan P

Abstract Surface integrity of micro components is a major concern particularly in manufacturing industries as most geometry of the products must meet out necessary surface quality requirements. Advanced machining process like electrochemical micro machining possess the capabilities to machine micro parts with best surface properties exempting them from secondary operations. In this research work, different electrolytes have been employed for producing micro holes in A286 super alloy material to achieve the best surface quality and the measurement of surface roughness and surface integrity to evaluate the machined surface is carried out. The machined micro hole provides detailed information on the geometrical features. A study of parametric analysis meant for controlling surface roughness and improvement of surface integrity has been made to find out the suitable parameters for machining. The suitability of various electrolytes with their dissolution mechanism and the influence of various electrolytes have been thoroughly studied. Among the utilized electrolytes, EG + NaNO3 electrolyte provided the best results in terms of overcut and average surface roughness.


2015 ◽  
Vol 15 (3) ◽  
pp. 309-318 ◽  
Author(s):  
Suha K. Shihab ◽  
Zahid A. Khan ◽  
Arshad Noor Siddiquee

AbstractEffect of cryogenic hard turning parameters (cutting speed, feed rate, and depth of cut) on surface roughness (Ra) and micro-hardness (µH) that constitute surface integrity (SI) of the machined surface of alloy steel AISI 52100 is investigated. Multilayer hard surface coated (TiN/TiCN/Al2O3/TiN) insert on CNC lathe is used for turning under different cutting parameters settings. RSM based Central composite design (CCD) of experiment is used to collect data for Ra and µH. Validity of assumptions related to the collected data is checked through several diagnostic tests. The analysis of variance (ANOVA) is used to determine main and interaction effects. Relationship between the variables is established using quadratic regression model. Both Ra and µH are influenced principally by the cutting speed and the feed rate. Model equations are found to predict accurate values of Ra and µH. Finally, desirability function approach for multiple response optimization is used to produce optimum SI.


2008 ◽  
Vol 375-376 ◽  
pp. 406-410 ◽  
Author(s):  
Zhan Qiang Liu ◽  
Peng Zhang ◽  
Peng Guo ◽  
Xing Ai

Surface roughness in a turning operation is affected by a great number of factors. Two of the most important factors are feed rate and the size of the corner radius. Surface roughness can be roughly determined to increase with the square of the feed rate and decrease with increased size of the corner radius. However, wiper insert geometries changed this relationship with the capability to generate good surface roughness at relatively higher feeds by transferring small part of the round insert edges into the straight cutting edges of the pointed insert. The principle of how wiper inserts behave different from conventional inserts as to the effects on the surface roughness is explored in this paper. Experimental study of the surface roughness produced in the turning of hardened mild steels using coated carbide tools with both conventional and wiper inserts is conducted. The test results prove the effectiveness of the wiper inserts in providing excellent surface roughness. The results also suggest that the use of the wiper insert is an effective way that significantly increases cutting efficiency without changing the machined surface roughness in high feed turning operations.


2011 ◽  
Vol 410 ◽  
pp. 236-239 ◽  
Author(s):  
Anil Kumar ◽  
S. Maheshwari ◽  
C. Sharma

In this experimental study attempt has been made to realize potential of cryogenic treatment in enhancing surface quality with fine aluminum and graphite additives powders in AEDM of nickel based super alloy Inconel 718. L36(23x36) Orthogonal Array has been selected to conduct and analyze experiments based on Taguchi methodology. Polarity, peak current, pulse on time, duty cycle, gap voltage, retract distance, concentration of fine aluminum and graphite powder added into the dielectric fluid are chosen as input process variables to study performance in terms of surface roughness (SR) using copper and deep cryogenically treated copper electrode. It is found experimentally that deep cryogenically treated copper electrode with addition of 6g/l graphite powder improves surface roughness appreciably. The same has been supported by SEM analysis of the machined surface.


2014 ◽  
Vol 14 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Suha K. Shihab ◽  
Zahid A. Khan ◽  
Aas Mohammad ◽  
Arshad Noor Siddiquee

AbstractThe cutting parameters such as the cutting speed, the feed rate, the depth of cut, etc. are expected to affect the two constituents of surface integrity (SI), i.e., surface roughness and micro-hardness. An attempt has been made in this paper to investigate the effect of the CNC hard turning parameters on the surface roughness average (Ra) and the micro-hardness (μh) of AISI 52100 hard steel under dry cutting conditions. Nine experimental runs based on an orthogonal array of the Taguchi method were performed and grey relational analysis method was subsequently applied to determine an optimal cutting parameter setting. The feed rate was found to be the most influential factor for both the Ra and the μh. Further, the results of the analysis of variance (ANOVA) revealed that the cutting speed is the most significant controlled factor for affecting the SI in the turning operation according to the weighted sum grade of the surface roughness average and micro-hardness.


2015 ◽  
Vol 13 ◽  
pp. 19-22 ◽  
Author(s):  
Gabriel Benga ◽  
Danut Savu ◽  
Adrian Olei

The paper presents the influence of various cutting regimes on the surface roughness, when a hardened bearing steel has been machined using both ceramic and PCBN cutting tools. There were used different cutting conditions varying cutting speed, feed rate and depth of cut in order to determine the influence of each cutting parameter on the surface finish.


2013 ◽  
Vol 685 ◽  
pp. 57-62
Author(s):  
Seyyed Pedram Shahebrahimi ◽  
Abdolrahman Dadvand

One of the most important issues in turning operations is to choose suitable parameters in order to achieve a desired surface finish. The surface finish in machining operation depends on many parameters such as workpiece material, tool material, tool coating, machining parameters, etc. The purpose of this research is to focus on the analysis of optimum cutting parameters to get the lowest surface roughness in turning Titanium alloy Ti-6Al-4V with the insert with the standard code DNMG 110404 under dry cutting condition, by the Taguchi method. The turning parameters are evaluated as cutting speed of 14, 20 and 28 m/min, feed rate of 0.12, 0.14 and 0.16 mm/rev, depth of cut of 0.3, 0.6 and 1 mm, each at three levels. The Experiment was designed using the Taguchi method and 9 experiments were conducted by this process. The results are analyzed using analysis of variance method (ANOVA). The results of analysis show that the depth of cut has a significant role to play in producing lower surface roughness that is about 63.33% followed by feed rate about 30.25%, and cutting speed has less contribution on the surface roughness. Also it was realized that with the use of the confirmation test, the surface roughness improved by 227% from its initial state.


2020 ◽  
Vol 979 ◽  
pp. 16-21
Author(s):  
Lakshmanan Poovazhgan

In recent years, aluminum alloys reinforced with nanosized ceramic particulates are finding wider applications in various engineering industries like automobile, aircraft, electronics and sports. The requirement of accurate machining of nanocomposite has also gets increased. In this research work, aluminum alloy 6061 reinforced with 1.5 Wt. % of nanoB4C particulate was fabricated in cylindrical shape using ultrasonication assisted casting process. Medium duty lathe with poly crystalline diamond insert tool of 1600 grade was used to turn the Al/B4C nanocomposites. During turning of Al/B4C nanocomposites, cutting parameters like depth of cut, speed and feed were varied as per predefined level. Surface roughness of machined surface and power consumption during machining were measured using surface roughness tester and wattmeter respectively. ANOVA analysis was carried out and the optimum parameters for machining the nanocomposite were found out using MINITAB software. The nanocomposite machined with optimum parameters show good surface finish and consumed minimum power.


2020 ◽  
Vol 4 (2) ◽  
pp. 59 ◽  
Author(s):  
David Adeniji ◽  
Julius Schoop ◽  
Shehan Gunawardena ◽  
Craig Hanson ◽  
Muhammad Jahan

Thermoplastic materials hold great promise for next-generation engineered and sustainable plastics and composites. However, due to their thermoplastic nature and viscoplastic material response, it is difficult to predict the properties of surfaces generated by machining. This is especially problematic in micro-channel machining, where burr formation and excessive surface roughness lead to poor component-surface integrity. This study attempts to model the influence of size effects, which occur due to the finite sharpness of any cutting tool, on surface finish and burr formation during micro-milling of an important thermoplastic material, polycarbonate. Experimental results show that the depth of cut does not affect either surface finish or burr formation. A proposed new sideflow model shows the dominant effect of cutting-edge radius and feed rate on surface finish, while tool edge roughness, coating and feed rate have the most pronounced influence on burr formation. Overall, a good agreement between the experimental data and the proposed size effect model for the machining of thermoplastic material was found. Based on these results, tool geometry and process parameters may be optimized for improved surface integrity of machined thermoplastic components.


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