Review

An overview of conventional and non-conventional techniques for machining of titanium alloys

¹ Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam
² Faculty of Civil Engineering, Ton Duc Thang University, Ho Chi Minh City, Vietnam
³ Department of Metallurgical and Materials Engineering, Federal University of Technology Akure, PMB 704, Ondo State, Nigeria
⁴ Department of Mining and Metallurgical Engineering, University of Namibia, P.O. Box 3624, Ongwediva, Namibia
⁵ National Agency for Science and Engineering Infrastructure, PMB 391 Garki, Abuja, Nigeria
⁶ Department of Mining, Materials and Petroleum Engineering, Dedan Kimathi University of Technology, Nyeri, Kenya
⁷ Department of Mechanical Engineering, Jomo Kenyatta University, Nairobi, Kenya
⁸ School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg 2050, South Africa
⁹ African Academy of Sciences, Nairobi, Kenya

^* e-mail: mobodunrin@gmail.com

Received: 8 June 2020
Accepted: 23 August 2020

Abstract

Machining is one of the major contributors to the high cost of titanium-based components. This is as a result of severe tool wear and high volume of waste generated from the workpiece. Research efforts seeking to reduce the cost of titanium alloys have explored the possibility of either eliminating machining as a processing step or optimising parameters for machining titanium alloys. Since the former is still at the infant stage, this article provides a review on the common machining techniques that were used for processing titanium-based components. These techniques are classified into two major categories based on the type of contact between the titanium workpiece and the tool. The two categories were dubbed conventional and non-conventional machining techniques. Most of the parameters that are associated with these techniques and their corresponding machinability indicators were presented. The common machinability indicators that are covered in this review include surface roughness, cutting forces, tool wear rate, chip formation and material removal rate. However, surface roughness, tool wear rate and metal removal rate were emphasised. The critical or optimum combination of parameters for achieving improved machinability was also highlighted. Some recommendations on future research directions are made.