EFFECT OF WIRE-EDM PROCESS PARAMETERS ON CUTTING SPEED OF AL6061 HYBRID COMPOSITE

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1 International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 10, October 2017, pp , Article ID: IJMET_08_10_023 Available online at ISSN Print: and ISSN Online: IAEME Publication Scopus Indexed EFFECT OF WIRE-EDM PROCESS PARAMETERS ON CUTTING SPEED OF AL6061 HYBRID COMPOSITE Department of Mechanical Engineering, Saveetha School of Engineering, Saveetha University, Thandalam, Chennai, India ABSTRACT In this paper, the effect of different wire electrodes used in wire electrical discharge machining (WEDM) on the machining characteristics of Al/SiC/Graphite has been presented. Aluminium metal matrix composites reinforced with silicon carbide particulate find several applications due to their improved mechanical properties for a wide variety of aerospace and automotive applications. The hybrid composite (Al6061/SiC/Graphite) is prepared by stir casting method. These reinforcements have micron size particles of SiC & graphite. Three types of wire materials such as Brass wire, zinc coated wire and diffused coated wires have been used. The process performance is measured in terms of cutting speed. Taguchi experimental design strategy is used in the experimentation. Six process parameters, namely pulse on time, pulse off time, peak current, gap set voltage, wire feed and Wire tension have been considered. Cutting speed, kerf width, surface roughness is calculated for each experiment. In this paper cutting speed is compared and studied for the different wire electrodes. In this study, diffused coated wire electrode s performance is better than the other wire electrodes. Keywords: WEDM, Hybrid composite, Taguchi method, Cutting speed and Stir casting. Cite this Article: A. Muniappan, C. Thiagarajan, P.V. Senthiil, V. Jayakumar and T. Shaafi, Effect of Wire-Edm Process Parameters on Cutting Speed of Al6061 Hybrid Composite, International Journal of Mechanical Engineering and Technology 8(10), 2017, pp INTRODUCTION Aluminium metal matrix composites (MMCs) reinforced with silicon carbide particulate (SiCp) find several applications due to their improved mechanical properties over the conventional metals for a wide variety of aerospace and automotive applications.in the recent days, Al matrix composites have been used for the production of automotive parts such as engine piston, cylinder liner, brake disc/drum etc.[1].however, the presence of editor@iaeme.com

2 Effect of Wire-Edm Process Parameters on Cutting Speed of Al6061 Hybrid Composite discontinuously distributed hard ceramic in the MMCs made them as difficult-to-cut materials for conventional machining methods. Wire electrical discharge machining (WEDM) is an indispensable machining technique for producing complicated cut-outs.by 1975; its popularity was rapidly increasing, as the process and its capabilities were better understood by the industry [2]. Wires used in wire electrical discharge machining are the core of the system.in WEDM, material is eroded from the work-piece by a series of discrete sparks occurring between the work piece and the wire separated by a stream of dielectric fluid, which is continuously fed to the machining zone [3]. Brass wire electrode is used extensively as a tool for WEDM. However, along with the recent diversification in applications of manufacturing fields, demand is expanding for a wire electrode with performance superior to the conventional brass wire electrode. These electrodes in use are generally zinc coated wire with a copper/brass alloy or steel core, the brass containing either a small amount of Cr, or a high concentration of Zn. Huang et al. [4] argued that several published works [5,6,7] are concerned mostly with the optimization of parameters for the roughing cutting operations and proposed a practical strategy of process planning from roughing to finishing operations. 2. PREPARATION OF HYBRID COMPOSITE In this study, the hybrid MMC has been fabricated by stir casting process. The hybrid composite consists of 10 wt% SIC and 5 wt% Graphite particulates in metal matrix Al6061 alloy. The Al alloy of 6061 is having great potential to be utilized in aerospace and automotive industries because of its high strength-to-weight ratio and good resistance to corrosion. Reinforcements SiC and graphite in particulate form are used to fabricate the hybrid composite. These reinforcements have micron size particles of SiC& graphite. 3. MACHINING PARAMETERS AND RESPONSE six input process parameters in WEDM, namely, pulse on time, pulse off time, pulse current, gap set voltage, the wire drum speed and wire tension were chosen to study their effects on SR and kerf width while machining the hybrid composite. The ranges of these process parameters were selected on the basis of the pilot experiments. The levels of various parameters and their designations are presented in Table 1. Table 1 Process parameters and their levels Symbol Process parameter Level 1 Level 2 Level 3 A Pulse on time B Pulse off time C Pulse current D Gapset Voltage E Wire drum speed F Wire tension EXPERIMENTAL DESIGN USING TAGUCHI METHOD Taguchi technique is an efficient tool for the design of a high-quality manufacturing system. It is a method based on OA experiments, which provide much reduced variance for the experiment with optimum setting of process control parameters. The six control parameters, that is, pulse on time (A), pulse off time (B), peak current (C),Gap set voltage (D), wire drum speed (E) and wire tension(f) at three levels were selected in this study editor@iaeme.com

3 5. EXPERIMENTAL SET UP: Experiments were conducted on Electronica Sprint cut (Electra-Elplus 40A Dlx) CNC wire electrical discharge machine to study the surface roughness, cutting speed and kerf width affected by the machining parameters at different levels. WEDM is a spark erosion process. The sparks are generated between the work piece and the wire electrode. The dielectric fluid is continuously fed into the machining zone with required pressure. The material is getting removed by a series of discrete sparks taking place at the area to be machined through electrothermal mechanism. During machining process small gap maintained between the work and wire material. The machined particles were flushed away by the continuous flow of the dielectric fluid. The wire is held by a pin guide at the upper and lower parts of the work piece. The work specimen size used in this study is 95 x 80 x 8 mm rectangular plate. Brass, Zinc coated brass and diffused coated wire electrodes of 0.25 mm diameter was used in this study. Deionised water was used as dielectric fluid at room temperature. During machining, the cutting speed was observed and documented. 6. RESULT AND DISCUSSION Figure 1 & Figure 2 shows cutting speed variation for Brass, Zinc coated and diffused coated wire electrodes. From the graph it is observed for lower pulse on time and pulse off time values zinc coated brass wire electrode gives better cutting speed comparison with brass wire electrode. Brass wire electrode gives better cutting speed at high range of input process parameters. Power consumption will be higher at high peak current and voltage. Surface roughness is poor at higher cutting speed. So zinc coated wire electrode performance is better than the brass wire electrode. For zinc coated wire electrode, the maximum cutting speed was observed at higher pulse on time and peak current. At high peak current, cutting speed was high due to more heat is generated. The cutting speed was high for wire electrodes at high discharge current at 230 units. Low cutting speed was observed for high discharge current and low pulse on time for all wire electrodes. So it is understood that cutting speed will be maximum for higher discharge current and pulse on time. At high pulse on time, the rate of material removed is also high. Ex. No. Pulse on Time Pulse off Time Table 4 Cutting speed with Process parameters Peak Current Gap set voltage Wire Feed Wire Tension Cutting Speed Zinc Brass Diffused µs µs A V m/min mm/min mm/min mm/min editor@iaeme.com

4 Effect of Wire-Edm Process Parameters on Cutting Speed of Al6061 Hybrid Composite Figure 1 Cutting speed comparison (bar chart) Figure 2 Cutting speed comparison (Line chart) 7. CONCLUSION Aluminium based hybrid metal matrix composites (Al6061/SiC/Gr) have been successfully fabricated by stir cast method by addition of reinforcement combined with preheating of particulates. Taguchi technique is effectively utilised to analyse the process parameters on performance characteristics in a wire electrical discharge machining of Al6061 hybrid editor@iaeme.com

5 composite. Based on the results and discussions the following conclusions are drawn. For lower pulse on time and pulse off time values zinc coated brass wire electrode gives better cutting speed comparison with brass and diffused coated wire electrodes. Power consumption will be higher at high peak current and voltage. In overall diffused coated wire electrode gives better cutting speed compared to other wire electrodes. Surface roughness is poor at higher cutting speed. REFERENCES [1] K.M. Shorowordia, T. Laoui, A.S.M.A. Haseeb, J.P. Celis, L. Froyen, Microstructure and interface characteristics of B4C, SiC and Al2O3reinforced Al matrix composites s: a comparative study, J. Mater Process. Technol. 142 (2003) [2] G.F. Benedict, Electrical discharge machining (EDM), Non-Traditional Manufacturing Processes, Marcel Dekker, Inc, New York & Basel, 1987, pp [3] A.B. Puri, B. Bhattacharyya, An analysis and optimization of the geometrical inaccuracy due to wire lag phenomenon in WEDM, Int. J. Mach. Tools Manuf. 43 (2003) [4] J.T. Huang, Y.S. Liao, W.J. Hsue, Determination of finish cutting operation number and machining-parameters setting in wire electrical discharge machining, J. Mater. Process. Technol. 87 (1 3) (1999) [5] Y.S. Tarng, S.C. Ma, L.K. Chung, Determination of optimal cutting parameters in wire electrical discharge machining, Inter, Mach. Tools Manuf. 35 (12) (1995) [6] D. Scott, S. Boyina, K.P. Rajurkar, Analysis and optimization of parameter combination in wire electrical discharge machining, Inter. J. Prod. Res. 29 (11) (1991) [7] Y.S. Liao, J.T. Huang, H.C. Su, A study on the machining parameters optimization of wire electrical discharge machining, Mater. Process. Technol. 71 (3) (1997) [8] Muniappan.A and Thiagarajan.C (2015) Experimental investigation of kerf width in WEDM process for hybrid Aluminium composite using Zinc coated Brass wire, International Journal of Applied Engineering research, Vol.10, No.33, pp [9] Muniappan.A and Thiagarajan.C (2015) Performance of wire electrodes on machining of hybrid Aluminium composite, International Journal of Applied Engineering research, Vol.10, No.65, pp [10] Muniappan.A and Thiagarajan.C (2015) Experimental investigation of kerf width in WEDM process for hybrid Aluminium composite using Zinc coated Brass wire, International Journal of Applied Engineering research, Vol.10, No.33, pp [11] Muniappan.A, Thiagarajan.C and Somasundaram.S (2017) Parametric Optimization of kerf width and surface roughness in Wire Electrical Discharge Machining (WEDM) of hybrid Aluminium (Al6061/SiC/Graphite) composite using Taguchi-based Gray Relational Analysis International Journal of Mechanical & Mechatronics Engineering IJMME-IJENS Vol:16 No:05, pp [12] Upinder Kumar, Rakesh Kumar and Aayush Mittal Multi Response Optimization of Parameters for Wire EDM Operation. International Journal of Mechanical Engineering and Technology, 8(7), 2017, pp [13] Manish Saini, Rahul sharma, Abhinav, Gurupreet Singh, Prabhat Mangla and Er. Amit Sethi. Optimizations of Machining Parameter In Wire EDM For 316l Stainless Steel by Using Taguchi Method, Anova, and Grey Analysis. International Journal of Mechanical Engineering and Technology, 7(2), 2016, pp [14] S. Madhavakrishnan and Dr. P. Suresh. Recent Developments in Wire EDM. Journal of Mechanical Engineering and Technology, 4(1), 2016, pp editor@iaeme.com