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A. A. Sri Rama Krishna ¹, G. Laxmaiah ¹, A. Siva Priya ¹

Affiliations
1 Mechanical Engineering Department, Chaitanya Bharati Institute of Technology (CBIT), Osmania University, Hyderabad, IN

Abstract

Advancement in technology has led to development of many materials with better qualities in order to develop products of greater value. This has led to a search for better materials to satisfy the ever growing demands of product requirement. Composite materials are one such group of materials, they are formed by combining two or more materials to achieve certain desired properties. Among composite materials Metal Matrix Composites (MMCs) are advanced materials in which metallic matrix (aluminium) is reinforced with hard ceramic such as Silicon Carbide to get superior properties like high strength, high stiffness, greater wear resistance, dimensional stability and ability to operate at elevated temperature. These materials are harder and comparatively have higher strength when compare to other materials therefore machining becomes difficult conventional machining process are not suitable for machining purpose due to which there is development in Non-conventional machining process one such process is EDM-(Electronic discharge machining) Metal removal rate (MRR), Surface roughness (SR) are the two most important parameters which can be measured and varied using EDM process. The surface roughness of the machined surfaces was measured with surface roughness measuring instrument SURFTRONIC 3+. The present paper deals with machining of metal matrix composites (MMCs) [aluminium + 30% SiC] In which MRR modelling has been carried out using axi-symmetric model of MMC during EDM machining. A FEA model of single spark EDM was developed to calculate the temperature distribution. Further, single spark model was extended to multi-discharge machining material removal was calculated by calculating the number of pulses and experiments were conducted using CNC Sinking Electrical Discharge Machine (CHMER Thai van Make) validation of model has been done by comparing experimental results with analytical results and good agreement was found out.

Keywords

Electrical Discharge Machining (EDM), Finite Element Method (FEM), Metal Removal Rate (MRR), Metal Matrix Composites (MMC).

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A. A. Sri Rama Krishna ¹, B. Chennakesava Rao ¹, N. Vekateswara Rao ¹, A. Siva Priya ¹, K. Anusha ¹

Affiliations
1 Department of Mechanical Engineering, Chaitanya Bharathi Institute of Technology, Gandipet, Hyderabad, IN

Abstract

As the world is advancing forth technically in the field of space research, missile and nuclear industry, very complicated and precise components having some special requirements are demanded by these industries. The challenge is taken by the new developments taking place in the manufacturing field. Advancement in technology has led to development of many materials with better qualities in order to develop products of greater value. This has led to a search for better materials to satisfy the ever growing demands of product requirement. Composite materials are one such group of materials, they are formed by combining two or more materials to achieve certain desired properties. The focus of present work is on machining MMCs in aluminum matrix with higher percentage of SiC_p. In order to machine typical profiles on these materials authors found that conventional processes are not suitable. Conventional machining is uneconomical for such materials and degree of accuracy and surface finish attainable is poor. Hence unconventional methods were chosen. Among the many unconventional processing techniques Electric Discharge Machining (EDM) has proved itself as effective in shaping such difficult to machine materials. The present paper deals with the study of Metal removal rate, Surface roughness, dimensional stability and microstructures machining of MMCs by varying EDM variables namely discharge current, electrode material, volume percentage of SiC_p, pulse duration.

Keywords

Electrical Discharge Machining (EDM), Metal Removal Rate (MRR), Metal Matrix Composites (MMC).

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A. A. Sri Rama Krishna ¹, P. Ravinder Reddy ¹

Affiliations
1 Dept. of Mech. Engg., CBIT, Gandipet, Hyderabad, IN

Abstract

The quality of the components produced during the turning of AI/SiC_p particulate metal-matrix composites is important as it influences to a great extent the performance of the finished component. In a machining operation surface quality depends more on the variables of processes rather than characteristic features of the material. Hence estimation of surface roughness in variation to the machining parameters and minimization of the same has become an essential requirement. This paper deals with the surface integrity of machined AI-SiC_p MMC material with AI-6061 as matrix with 10%, 20%, and 30% SiC_p of size 10 to 30 μm dispersed uniformly. Dry turning tests, at different cutting speeds (19.6, 31.4, 58.8, 100 m/min) with feed rates (0.05, 0.1, 0.2, 0.3mm/rev) and depths of cuts (0.5,1.0mm) were conducted in order to investigate effect of various parameters on surface quality. In addition, the surface roughness of the specimens was evaluated with respect to volume fraction of SiC_p particles. The surface quality was evaluated by using K10, K20, P20, P30 carbide tools and poly crystalline diamond tools. It was observed that under certain cutting conditions, the surface finish was comparable to that of polycrystalline diamond tool, obtained with P30 carbide tool.

Keywords

Surface Integrity, Metal Matrix Composites.

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