Tool Geometry Optimisation for LCO2 Assisted Milling of Ti6Al4V

Abstract

Titanium alloy Ti6Al4V is of great importance to the aeronautical and medical sectors due to its mechanical properties such as a high strength-to-weight ratio and corrosion resistance. On the downside, machining Ti6Al4V can lead to accelerated tool wear and poor surface finish of the machined part due to its low heat dissipation capacity. Traditionally, oil and water based metalworking fluids (MWFs) have been used to overcome such issues. However, new regulations and eco-friendly manufacturing trends suggest that conventional MWFs should be minimised, as they are hazardous to the environment and workers’ health. Additionally, titanium prostheses contaminated with oil can cause severe integration problems on the patient. This article researches the feasibility of replacing conventional emulsions with sustainable liquid carbon dioxide (LCO2) cooling. For this purpose, an optimisation of the tool geometry (helix angle, clearance angle and cutting edge geometry) for LCO2 assisted milling of Ti6Al4V was carried out, taking into account parameters such as cutting forces, surface roughness and the microstructure of the machined surface. This research contributes to the development of environmentally friendly and work safe manufacturing processes that meet the challenges of machining Ti6Al4V for aerospace and medical applications.