Research Output
Effect of Different Cutting Conditions on Tool Wear and Chip Formation in Drilling of Cobalt Chromium Molybdenum
Improvement on the Surface Quality in Machining of Aluminum Alloy Involving Boron Nitride Nanoparticles
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Publication
Cobalt-Chromium Molybdenum (CoCrMo) alloy is categorized under hard to cut material due to its unique combination characteristics such as high strength and low thermal conductivity. However, there was a problem during machining hard alloy material which is rapid tool wear. The tool wear will cause changes at tooltip geometry consequently has significant influence on the chip forming. There are some factors that influence tool wear which are cutting parameters, type of drill bit, and cutting fluids. In this study, a series of experiment were conducted to investigate the effect of cooling conditions on tool wear and chip formation during drilling this material. The cooling conditions used were dry, pure Karanja oil (MQL condition), and combination of Hexagonal boron nitride (hBN) nanoparticles with Karanja oil (MQL condition). The experiment was conducted under constant cutting speed of 20 m/min, and feed rate of 0.07 mm/rev through holes. Each hole was inspected when the tool wear reached 0.3 mm. The result showed that mixed of hBN with Karanja Oil (MQL condition) had lowest growth of flank wear and produced more holes compared to dry and pure Karanja oil condition. In addition, for chip formation, the size of lamellae produced was finest compared to other conditions.
Publication
Aluminum Alloys are used in a variety of applications due to their lightweight, strength-to-weight ratio and relatively ease of fabrication. In aerospace industry, millions of holes drilled annually on airframe structures. Normally, cutting fluids have been used to help reduce friction and heat. However, the use of cutting fluid is one of the major concerns when considering the environmental issues in machining. The disposal of used cutting fluid poses problems to the environment. This research investigates the effect of greener technique; hexagonal Boron Nitride nanoparticles dispersed in oil as compared to dry cutting and oil alone in through hole drilling operation Their impact on tool wear, surface roughness, and holes quality in terms of diameter accuracy, circularity and cylindricity were experimentally studied. Results showed that application of hexagonal Boron Nitride improved surface finish and produced better dimensional hole accuracy. The work clearly shows the important of nanoparticles in improving machinability of this material.