Flank-Milling of Integral Blade Rotors Made in Ti6Al4V Using Cryo CO2 and Minimum Quantity Lubrication

Abstract

This paper presents the machining of integral blade rotors (IBRs) made in Ti6Al4V using CO2 as cryogenic cooling. This kind of component is typical in gas turbines, pumps, and other rotary machines. A flank milling technique using polycrystalline diamond (PCD) tools and CO2+minimum quantity lubrication (MQL), denominated CryoMQL, is here presented as an alternative to conventional oil emulsions. The proposed approach implies a balance between technical and environmental issues. Cryogenics makes feasible the use of PCD tools avoiding problems derived from the reactivity of Ti6Al4V alloy with this type of cutting tool, which is directly related to cutting temperature. One key aspect is that CO2 has to be supplied and injected onto the cutting zone avoiding the risks of dry-ice formation, and the consequent clogging of both pipes and nozzles. For this purpose, a new device for CO2 delivery was developed, using gas and liquid CO2 simultaneously.