ElectroChemical Jet Machining of Titanium: Overcoming Passivation Layers with Ultrasonic Assistance

Abstract

The formation of passivating layers in some materials inhibits their machinability via electrochemical processes. These, relatively inert coatings, prevent direct attack by the incident electrolyte. This is particularly problematic in Electrolyte Jet methods.In this study the use of ultrasonics is explored for the purpose of assisting in removing of the passivating layer during machining processes. Experiments presented here show that the passivating scale which forms can be partially removed as a result of ultrasonic assistance thus enhancing overall machining performance.The use of ultrasonics during machining is demonstrated to favourably enhance feature aspect ratio by increasing depth and minimising kerf by 7% for identical process parameters.Surface textures of machined faces using ultrasonic assistance also demonstrate a reduction in Ra by 31% along the groove bottom due to an increase of low roughness areas previously known to be caused by an increase in high current density.Results obtained here suggest that there are significant advantages for using ultrasonic assistance during the Electrochemical Jet Machining of Ti alloys.