Machining of titanium alloys for medical application - a review

Abstract

Titanium alloys for their characteristics have acquired a prominent position in numerous industrial applications. Due to its properties, such as high resistance to corrosion, reduced density, high specific strength, and low Young’s modulus, titanium alloys became indispensable as a biomaterial with high use in medical devices, with special emphasis in the area of orthopedics. Problems associated with its manufacturing by conventional machining processes, such as milling, turning, and drilling are well known and studied. Its low thermal conductivity, high chemical reactivity, high hardness at high temperatures make it classified as difficult to machine material. Despite the already extensive knowledge about machining titanium alloys problems, and the constant technological development to overcome them, it is not yet possible to machine this material like other metals. This work is based on research and review papers from Scopus and Scholar from 2010 to 2020 and addresses the main issues related to the machining of titanium alloys used in medical devices manufacturing and current solutions adopted to solve them. From the research consulted it was possible to conclude that it is consensual that for milling, turning, and helical milling cutting speed can reach up to 100 m/min and up to 40 m/min in drilling. As for feed rate, up to 0.1 mm/tooth for milling and helical milling and up to 0.3 mm/rev for turning and 0.1 mm/rev for drilling. Also, that Minimum Quantity Lubrication is a valid and efficient solution to mitigate titanium alloys machining problems.

Tribological aspects of tool wear during turning Ti-15Mo alloy with cemented tungsten carbide cutting inserts prepared with different surface finishes

“…This can be attributed to the low friction and protection against heat propagation to the substrate. Similar information regarding the application of coatings was presented by Festas et al, 23 but the authors also pointed out that the possibility of applying PCBN and PCD tools should be emphasized, especially in high speed machining.…”

Milling of Three Types of Thin-Walled Elements Made of Polymer Composite and Titanium and Aluminum Alloys Used in the Aviation Industry

“…In addition to aluminum alloys, titanium alloys are also used in the aerospace industry [ 26 , 27 ]. They are used for their properties such as low density, high strength, low Young’s modulus and high resistance to corrosion [ 28 ]. Low thermal conductivity and high hardness of titanium alloys make them difficult-to-machine materials, yet in many applications they replace steels and aluminum alloys.…”

“…The machining of titanium alloys is characterized by lower maximum technological parameters, especially when compared to the machining of aluminum alloys. The cutting speed of titanium alloys can reach 100–110 m/min, and the feed rate can be up to 0.1 mm/tooth [ 28 , 35 ], but the use of coolants is required to use high cutting speed and feed rates [ 36 ]. In machining titanium alloys, an increase in surface roughness is strongly related to an increase in cutting speed [ 35 ].…”

“…In this study, the same technological parameters as found in milling are used to determine the effect of these parameters on cutting forces, surface roughness and accuracy resulting from gradual milling of thin-walled structures. The parameters were selected based on the literature review [ 2 , 25 , 28 , 35 , 46 , 50 , 53 , 54 ]; thus, their choice is a compromise for all analyzed materials. These parameters are optimal for milling polymer composites and aluminum alloys and maximum for milling titanium alloys.…”

Darcy–Forchheimer and Ohmic heating effects on GO-TiO2 suspended cross nanofluid flow through stenosis artery

“…It also increases the therapeutic effectiveness of agents in cancer treatment. 26 Festas et al 27 studied titanium alloys that have high confrontation to erosion, high precise power, and less Young's modulus; therefore, it has become an effective biomaterial in medicinal sciences. Graphene oxide has antimicrobial properties, and it can easily combine with a host of nanomaterials.…”