Mathematical model of multiflute drill point

Multiflute drilling is an efficient means of making high accuracy holes without reaming. Because of the current lack of a comprehensive mathematical model for this kind of drilling, this paper presents a complete and simple method for designing multiflute drills. There are three special features of the proposed model. The first is that rotational axial-type cutting tools and disk-type abrasive wheels are modeled by revolution geometry, so that the normals and tangent vectors of flute and flank surfaces can be obtained explicitly. Consequently, rake and clearance angles of cutting and chisel edges can be investigated according to recommended ISO standards. The second feature is that the mathematical models of flute and flank surfaces are integrated, so that cutting and chisel edges and their various characteristic angles can be obtained by numerical calculation. Finally, a simple way to determine the rake angles and wedge angles and clearance angles is presented by using the unit normals of the ISO-recommended reference planes. To verify the validity of this methodology, a designed three-fluted drill was machined on a 6-axis tool-grinding machine. This model is comprehensive, simple, easy to use, and capable of describing a wide range of drill design features.  2002 Published by Elsevier Science Ltd.