Wear mechanism of coated and uncoated carbide cutting tool in machining process
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Mohd Shahir Kasim and Mohd Amri Sulaiman Department of Process, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 49100 Hang Tuah Jaya, Melaka, Malaysia
Siti Haryani Tomadi Faculty of Mechanical Engineering, Universiti Malaysia Pahang, 26300 Kuantan, Pahang, Malaysia (Received 30 October 2015; accepted 1 December 2015)
A carbide cutting tool is widely used in machining process due to its availability and being cheaper than a better performance cutting tool, such as cubic boron nitride. The carbide cutting tool also has substantial hardness and toughness that is suitable to be applied in intermittent cutting. This paper presents the case study of a wear mechanism experienced on the cutting edge of the coated and uncoated carbide tools in turning and milling processes. The wear mechanisms of carbide cutting tools were investigated in machining Inconel 718, titanium alloy Ti–6Al–4V extra-low interstitial, and aluminum metal matrix composite (AlSi/AlN MMC) at their high cutting speed regime. The tools failed primarily due to wear on the flank and rake faces. The failure mode of the carbide cutting tools was similar regardless of the machining operations and coating is believed to enhance the tool life, but once removed, the tool fails similar to that with the uncoated tool.
I. INTRODUCTION
The cutting process occurs when a small volume of material around the cutting edge is removed either in a continuous or intermittent cut. This cutting edge/work– piece interface determines the performance of the tool, the machinability of the material and the quality of the machined surface. During the cutting process, many events occur at the said interface that cannot be observed by the naked eye. They are tool vibration, tool wear, metal flow, and increasing temperatures, which could only be estimated through analytical and experimental methods. Wear rate is defined as the volume or mass material removed per unit time or per unit sliding distance and is a complex function of time.1 The initial period during which the wear rate changes is known as the “run-in” or “break-in” period. Wear during run-in depends on the initial material structure and properties and on surface conditions such as surface fluids.2 Wear of the cutting edge is caused mainly by load, friction, and high temperature. Wear mechanism could be classified as adhesion, abrasion, diffusion, oxidation, and fatigue.3
Contributing Editor: Mohd Fadzli Bin Abdollah a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2015.382 J. Mater. Res., 2015
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Inconel 718 has the ability to maintain most of its strength even after long exposures to elevated temperatures and is the only material suitable for combustion sections of the jet engines.4 Therefore, it is considered to be the most difficult machine materials. Its high alloy content and high strength offers plastic deformation resistance during machining that leads to rapid work hardening. This problem occ
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