Study of Cryogenics in CNC Milling of Metal Alloys

Using cutting fluids in machining operations is widely accepted by industries as an effective method to improve tool life and surface quality of machined parts by controlling cutting temperature, lubrication and removing swarf. Owing to the environmental, health and cost issues related with cutting fluids, researchers are seeking alternative methods such as dry, minimum quantity lubricant, chilled air and also cryogenic cooling techniques.
The aim of this paper is to study the effects of cryogenic cooling using liquid nitrogen in CNC milling of typical metal alloys used in the automotive, aerospace and medical industrial sectors. Two types of metals, aluminium T6 alloy and aerospace grade titanium are machined under dry, wet (conventional coolant) and cryogenic conditions. The results clearly indicate that using cryogenic methods significantly reduced surface roughness and tool wear for the machining of both materials. For titanium machining surface roughness reduced by as much as 62% and for aluminium machining by as much as 50%. Tool wear was also shown to be significantly reduced as a result of using cryogenic methods when compared with other more conventional cutting methods.