A helical milling and oval countersinking end-effector for aircraft assembly

Abstract In order to meet the high quality, reliability and high efficiency requirements of aircraft assembly, a new multifunction end-effector (MFEE) is developed, which integrates three functions: drilling, helical milling and oval countersinking. After an introduction to the design of the MFEE, the working principle of automatic oval countersinking is discussed in detail, which has rarely been studied before in literature. The architecture of the whole drilling system is elaborately presented, and particular emphasis is put on the key techniques to guarantee hole quality, which are hole position compensation, normal vector adjustment and countersinking depth control. Finally, results of drilling experiments conducted on aluminum 7050-T6 alloy and titanium Ti–6Al–4 V alloy are presented. It is shown that the system could improve the assembly quality and drilling speed of aircraft components effectively. The position accuracy could be controlled within ± 0.5 mm, the normal direction accuracy was better than 0.5°, and the countersinking depth variation could be controlled within 0.02 mm at the worst case, all the machined holes and oval countersinks satisfy both the geometric dimensions and surface roughness.