Investigating the Machining Characteristics of Titanium Using Ultrasonic Machining

Abstract

Titanium has been known as the metal of the future for last few decades owing to its ever increasing applications in aerospace; marine; defense; nuclear energy; missiles; chemical production; hydrocarbon processing; power generation; desalination; nuclear waste storage and processing; metal recovery; offshore; marine deep sea applications; anodes; automotive components, food and pharmaceutical processing, medical implants and surgical devices and many other emerging fields of science and technology. Titanium is branded as difficult-to-machine metal as the conventional machining processes are unable to provide cost-effective solution for its commercial machining. Titanium is machined commercially by non-traditional methods such as Electric Discharge Machining (EDM) and Laser Beam Machining (LBM), but the surface quality obtained is not satisfactory from the prospect of surface integrity as well as surface finish. Ultrasonic Machining (USM) is another non-traditional machining process that is widely used in commercial machining of hard and brittle materials such as ceramics, refractory materials and precision stones. USM is a process known for its capabilities in providing excellent surface finish without any significant alterations is surface integrity or structure of the work material. Moreover, the compressive stress induced in the sub-surface as a result of repeated impacts of abrasive grains contributes in improving the fatigue strength of the machined components; which is a very important aspect especially for a material like titanium. Hence, the study was aimed to investigate the machining characteristics of titanium using different tool materials in ultrasonic machining and to model these characteristics for their application in the concerned manufacturing industry. The machining characteristics investigated are material removal rate (MRR); tool wear rate (TWR) and surface roughness.