Control system for axial deviation of holes in deep drilling.

Axial deviation of holes is a serious problem in deep drilling operations. This paper presents the development of a new drilling tool with a tool path control mechanism and in-process sensing system for hole deviation. Essentially, the cube corner prism is mounted on, the tool head for measuring of the machining position by laser. When the position of the tool head deviates from the setting axis, the guide- pad on the tool head slightly moves up and down in the radial direction with each tool revolution. As a result, the drilling point is shifted toward the radial direction. This method is verified to be effective for accurate deep drilling because the tool point moves along the setting axis of the laser.