A proposal of drilling unit for robotic machining

Abstract

In the assembly of large aircraft, drilling is often performed onsite after components are assembled, and many holes are still drilled by manual labor. In this unusual condition, it is difficult to apply conventional CNC machining. The authors have been proposing soft machining, a machining method that copies human drilling, as a machining method suitable for robotic drilling. In soft machining, thrust force is controlled to be smaller than that in CNC machining, and hole widening and burrs are less likely to be generated. In addition, vibration can be controlled by optimizing arm layout and drill shape. A twist drill with a 135° tip angle that was resharpened to a 115° tip angle at the center of the drill showed high performance in suppressing vibration. These indicate that soft machining can be applied to robotic drilling.