Browsing by Author "Bonney, J.."

Filter results by typing the first few letters
Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Influence of cutting parameters and tool wear on acoustic emission signal in high-speed turning of Ti-6Al-4V Alloy
    (Scholarlink Research Institute, 2012) Fadare, D. A.; Sales, W. F.|; Bonney, J..; Ezugwu, E. O
    Titanium and its alloys are an important group of engineering materials, with a wide range of applications in aerospace, aircraft, automotive, chemical and biomedical industries. They have excellent combination of strength and fracture toughness as well as low density and excellent corrosion resistance but with poor machinability due to their low thermal conductivity and high chemical reactivity with cutting tool materials. In this study, the effects of cutting parameters and tool wear on the Acoustic Emission (AE) signal in high-speed turning of Ti-6Al-4V alloy with new generation of cemented carbide tools was investigated. Machining trials were conducted at different cutting conditions, the AE signals were acquired and the signal features in the time-domain (mean, standard deviation, amplitude, root mean square, skewness, and kurtosis) and signal features in the frequency-domain (frequency and amplitude) were extracted. The essence of this study was to identifying the features of AE signal capable of being used as potential process indicator for development of automated monitoring and control system for turning of Ti-6Al-4V alloy. The results demonstrated AE signals as potential indicator for Tool Condition Monitoring (TCM) in turning of titanium Ti-6Al-4V alloy.
  • Thumbnail Image
    Item
    Machining of nickel-base, Inconel 718, alloy with ceramic tools under finishing conditions with various coolant supply pressures
    (Elsevier Limited, 2005) Ezugwu, E. O.; Bonney, J..; Fadare, D. A.; Sales, W. F
    Machining of Inconel 718 with whisker reinforced ceramic tool gave better performance in terms of tool life under high-pressure coolant supplies up to 15 MPa compared to conventional coolant supplies. The use of 15 MPa coolant supply pressure tend to suppress notching during machining thus improving tool life, while the use of higher coolant supply pressure of 20.3 MPa did not show improvement in tool life due probably to accelerated notch wear caused by water jet impingement erosion, Cutting forces decreased with increasing coolant supply pressure due to improved cooling and lubrication at the cutting interface as well as effective chip segmentation ensured by the momentum of the coolant jet. Surface roughness generated were well below the rejection criteria. This can be attributed to the round shape of the insert which tend to encourage smearing of the machined surface with minimum damage. Microstructure analysis of the machined surfaces show evidence of plastic deformation and hardening of the top layer up to 0.15 mm beneath the machined surface as a result of increase in dislocation density.