The aero-engine blade with characteristics of complex curved surfaces and variable thickness is unable to be accurately and automatically detected by conventional inspection method. For this issue

an automatic and non-destructive inspection method based on the combination of ultrasonic testing and industrial robot is proposed. Firstly

according to the structural characteristics of the blade

the ultrasonic longitudinal waves are applied to detect the defeats and measure the thickness of blade body through vertical incidence and to inspect the LTE (the leading and the trailing edges) and roots of blade through oblique incidence

respectively. Secondly

the defeats and thickness of a test block of blade are also detected and measured respectively based on the manipulator scanning trajectory planned according to the CAD model of blade. The inspection results show that a flat bottom hole with a minimum diameter of 0.15mm and a crack with a width of 0.15mm can be identified

the accuracy of thickness is ±0.03mm

and the inspection period for whole blade is less than 20min. These results meet the requirements of inspection for blade and indicate that the robotic ultrasonic non-destructive testing technique is effective for automatic inspection of blade.