Investigation of the Machining of Titanium Components for Lightweight Vehicles 2010-01-0022
Due to titanium's excellent strength-to-weight ratio and high corrosion resistance, titanium and its alloys have great potential to reduce energy usage in vehicles through a reduction in vehicle mass. The mass of a road vehicle is directly related to its energy consumption through inertial requirements and tire rolling resistance losses. However, when considering the manufacture of titanium automotive components, the machinability is poor, thus increasing processing cost through a trade-off between extended cycle time (labor cost) or increased tool wear (tooling cost). This fact has classified titanium as a “difficult-to-machine” material and consequently, titanium has been traditionally used for application areas having a comparatively higher end product cost such as in aerospace applications, the automotive racing segment, etc., as opposed to the consumer automotive segment. Herein, the problems associated with processing titanium are discussed, and a review of cutting tool technologies is presented that contributes to improving the machinability of titanium alloys. Additionally, non-conventional machining techniques such as High Speed Machining and Ultrasonic Machining are also reviewed. Additional factors specific to machining titanium alloys are also discussed, a crucial one being its non-conformity with standard tool wear models. Subsequently, the results of a controlled milling experiment on Ti-6Al-4V are presented, to evaluate the relationship between tool preparation/process parameters and tool wear and for a comparison with traditional wear models.