New M.Tech. Thesis Submitted from Production

STUDY THE EFFECT OF DIFFERENT WIRE ELECTRODES ON MACHINING CHARACTERISTICS OF INCONEL825 WITH WEDM By Maninderpreet Singh

Abstract

Scientists across the world have developed many super alloys, which are of high strength and heat resistant for use in industries aerospace and defence. Ni-based alloys are resistive to degradation in oxidizing and eroding environment, have high strength even at high temperatures. Many high performance wires have been developed over the time to enhance the performance of WEDM machining process. The aim of our study was to investigate the еffеct of process parameters on the performance characteristics of WЕDM for Nickеl-basеd alloy material, with brass wire and diffusion annealed wire. The specimen was prepared and preliminary еxpеrimеnts were conducted, to identify the machining parameters and decide the ranges and levels of each machining parameter. Then main experiment was conducted by machining the specimens using different wire еlеctrodеs and record the machining performances. Detailed еxpеrimеntation was based on Taguchi design of еxpеrimеnts to analyse the impact on various responses by machining parameters. The results of the experimentation were analysed using SEM and ANOVA analysis to show the significant variations in response parameters with different wire electrodes. The experimental results revealed that wire wear and cutting rate are maximum with diffusion annealed. The surface roughness produced by plain brass

wire is higher than the surface roughness produced by diffusion annealed wire

New M.Tech. Thesis Submitted from Production

ANALYTICAL MODELING OF INPUT ENERGY CONSUMPTION,SURFACE ROUGHNESS AND MATERIAL REMOVAL RATE IN BALL END MILLING OPERATION by Aashish Dhiman

Abstract

Ball end milling operation is commonly used for producing flat and contoured surfaces of manufacturing dies and moulds etc. due to its high quality and productivity nature. It is very sensitive

manufacturing operation because of complex tool geometry and involvement of large number of process parameters. The energy consumption, surface quality and Material Removal Rate (MRR) play a vital role for any manufacturing process to be sustainable. The present work presents an analytical approach to predict energy consumption, surface roughness and MRR during ball end milling operation. The modeling procedure begins with analytical prediction of uncut and cut chip geometry followed by the evaluation of the associated angles and further determination of the cutting forces. These cutting forces, cutting speed and milling time were used to calculate the energy consumption during the operation. In analytical model of surface roughness, the cusp height was calculated from topography of the surface produced by the ball end mill tool geometry which was further used to calculate the theoretical average surface roughness (��). The analytical models of MRR were developed from geometry and the impressions left by the ball end mill on the work surface. Experiments were performed using 6 mm diameter ball end mill on CNC Vertical Milling Center on EN8 material work piece for different speeds (1000, 1500, 2000 RPM), different feed rates (400, 600, 800 mm/min) and different depth of cuts (0.10, 0.15, 0.25 mm) to validate the proposed analytical models. The radial depth of cut was kept 1 mm during all experiments. The proposed analytical model of energy consumption shows comparatively higher error than the error found by calculating energy consumption based upon cutting forces model available in literature (Sonawane and Joshi, 2010) for EN8 material whereas it shows comparatively less error for Inconel 718 material. An error of 94.044 % to 122.793 % and -52.593 % to -28.705 % had been observed in predicting surface roughness and MRR respectively by the proposed analytical models. The results predicted by the proposed analytical models of surface roughness and MRR matches exactly with the expected results of surface roughness and MRR presented in Table 1 in the research paper by Quintana et al. (2010) but the final equations for these models by them not give satisfactory results. The effect of the various machining variables on the different input and output parameters predicted by the proposed models comes out to be of the same trend as observed in the literature.