Deep hole drilling in metals using abrasive-waterjets

This paper addresses the deep (1-3 m) drilling of metals with about 19-mm-diameter holes. Experimental simulations and drilling tests were conducted to validate three selected drilling concepts and to determine the specific parameters, strategies, and techniques to be incorporated in a drill head design. Two drill head concepts were found feasible. In the first, a rectangular-shaped abrasive-waterjet (AWJ) with a radial. power gradient was used. By rotating the workpiece, the drill only needs to be axially advanced into the hole. In the second concept, a rotary drill was used with a rotation axis radially offset relative to the workpiece axis of rotation. It was demonstrated that high-quality holes could be drilled with a surface finish of about 2 mu m. It is projected that metals can be drilled at rates of 0.5 m/hr for steel and 0.3 m/hr for tungsten.