Obtaining high surface quality in electrolyte jet machining TB6 titanium alloy via enhanced product transport

Abstract

Numerous components used in the aerospace industry, such as helicopter rotor hubs and aero-engine casings, require high surface quality because they must endure extreme conditions. Most of those components are made of titanium alloy materials. However, it is difficult to obtain high surface quality for those titanium alloy materials by electrolyte jet machining owing to the high sensitivity of these materials to changes in the flow field. A disordered flow field will result in pitting corrosion and product accumulation, which will degrade the quality of the machined surface. It had been reported that specially designed structures at the tool end could improve the machined surface quality. In this study, several types of tools with different sloping structures at their ends were designed to enhance the machined surface quality in electrochemical jet macro machining. Numerical simulations were applied to investigate the influence of these sloping structures on the machining flow field distribution. The simulation results revealed that an upward-sloping inclined end could improve the electrolyte flow rate, reduce the dead zone, and limit the influence range of the electric field. In contrast, a downward-sloping inclined end caused flow field disorder, which resulted in serious pitting and electrolytic product accumulation. Experiments were also conducted to verify these results, which revealed that the electrolytic product transport capacity was improved and then high surface quality was obtained by the tool with an upward-sloping end face. The groove machined using this tool possessed a smoother surface, sharper edge, and lower surface roughness compared with grooves machined using other tools. In combination with a numerical control system, the proposed tool could be used to fabricate aerospace parts composed of titanium alloys, as the machined surface quality could meet the requirements for industrial production.