A Parametric Model of Drill Edge Angles using Grinding Parameters
In order to optimize drill geometry according to cutting resistance, experiments have been carried out, trying to evaluate the influence of local edge angles (direction and rake). Many works deal with drill point geometry models, however, some of them have a complex approach meant to implement CAD devices (Fugelsol, 2001; Vangness et al., 1995; Kang et al., 1996; Jung-Fa et al., 2002), and others use raw approximations (Yang et al., 2002) which are not compatible with the fine local geometry description required for a further cutting phenomenon understanding. The aim of this work consists into taking into account the complete grinding parameters, nevertheless, simple expressions of the drill cutting geometry is intended. Indeed, as results are used in an experimental approach, analytical formulas are required. Here, the grind is considered as a torus which has got a helical trajectory along the drill axis. Projection of the created solid is calculated and allows generating a close approximated flute. Thus, edge equations are given by the intersection of the flute and the drill tip, modelled by a conic shape. Direction angles (p and r) and cutting angles (f and o) are then calculated from the edge equations. This method also enables to calculate these parameters for staged tip drills.
Sylvain LAPORTE, Jean-Yves KNEVEZ, Olivier CAHUC, Philippe DARNIS
Reçu le 1 mars 2006.
Accepté le 1 décembre 2006.
Drill model, Grinding, Drill Tip Geometry.