To stress the issues of fabrication high-aspect-ratio small holes with low damage

high efficiency and high precision

laser and shaped tube electrochemical hybrid machining (Laser-STEM) has been proposed. In Laser-STEM

the laser is guided to the machining zone by internal total reflection through the hybrid tool electrode

in which the materials could be removed by laser processing at the center and electrochemical machining at the surrounding area synchronously

thus high-aspect-ratio small holes with high surface quality could be processed. The coupling method and mechanisms between the laser and hybrid tool electrode were studied. A high efficiency and stable laser transmission has been achieved. Feasibility of processing small holes with high efficiency and precision by Laser-STEM has been proven by observing the experimental phenomena and variation of the machining gap. Moreover

the relationship between the change of hybrid machining current signal and the machining state was established. Micro holes with a diameter of 1.25 mm

a depthdiameter ratio of 125:1

without recast layer and microcracks were processed on titanium alloy and nickel-based superalloy. The proposed hybrid processing method can be used for efficient and precise machining of micro holes with high surface quality and large aspect ratio for key components of aero-engines and gas turbines.