Manufacturing Technology Today

R. Suresh ¹

Affiliations
1 Department of Mechanical and Manufacturing Engineering, M.S. Ramaiah University of Applied Sciences, Bangalore, Karnataka, IN

Abstract

Metal matrix composites (MMC) have been found to be useful in a number of engineering applications and particle reinforced aluminum MMCs have received considerable attention due to their excellent engineering properties like high strength to weight ratio, high toughness, high impact strength etc. But these materials are generally regarded as extremely difficult to machine, because of the abrasive characteristics of the reinforced particulates. This paper focuses on effect of cutting parameters on thrust force, surface roughness and burr height during drilling of MMCs. In the present work, discuss the influence of spindle speed and feed rate on drilling the Al-2219+8%B₄C (mono) composite and Al-2219+8%B₄C+3%Gr (hybrid) composite. The composites were fabricated using stir casting method. The drilling experiments were conducted by CNC machine with TiN coated HSS and carbide tools at various spindle speeds and feed rates. The thrust force, burr height and surface roughness of the drilled hole were investigated with attention paid to the effects of boron carbide and graphite particles composites. The experimental results show that the feed rate has more influence on thrust force and surface roughness. Hybrid composites exhibit lesser thrust force and discontinuous chips were produces when compared with mono composite during drilling process. It is due to the solid lubricant property of graphite which reduces the lesser thrust force, burr height and lower surface roughness. The holes surface finish was evaluated and very good results, exceeding standard values for drilling, were obtained with carbide tool at low feed and high speeds.

Keywords

Metal Matrix Composites (MMC’s), Thrust Force, Burr Height, Surface Roughness.

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R. Suresh ¹

Affiliations
1 Department of Mechanical Engineering, Alliance College of Engineering and Design, Alliance University, Bengaluru, Karnataka, IN

Abstract

This paper presents results of an experimental investigation of turning of hardened AISI H13 die steel, focusing on the effect of cutting parameters on work surface integrity. The experiments were performed under dry cutting conditions using multilayer (TiN/MT TiCN/Al₂O₃) coated carbide tools. Surface integrity parameters like, surface and subsurface alterations and through thickness residual stresses were investigated to establish the effects of dry cutting on the surface integrity of the machined component. Surface and subsurface deformation were examined using a scanning electron microscope (SEM) and the residual stress distributions by X-ray diffraction technique. Various forms of surface damages were observed under different cutting conditions. The results obtained from surface examination showed a strong correlation between cutting conditions and surface integrity. A microstructural analysis shows the formation of a thin white layer less than 3~4 μm and severe plastic deformations beneath the machined surface. The favorable compressive residual stresses were obtained at low cutting speed with high feed rate and depth of cut. A wide range of residual stress distributions beneath the machined surface were obtained depending on the cutting conditions.

Keywords

Hard Turning, Coated Carbide Tool, Surface Integrity, Residual Stress Distribution.

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