Title: Influence of the ploughing effect on the vibratory drilling behaviour

Authors: Nicolas Guibert, Henri Paris

Addresses: G-SCOP Laboratory, 36 Av Felix Viallet, Grenoble 38031, France. ' G-SCOP Laboratory, 36 Av Felix Viallet, Grenoble 38031, France

Abstract: The poor removal of chips in deep drilling of small diameter is often the cause of tool breakage and poor quality surface. The vibratory drilling enables the chip to be split thanks to the axial vibrations of the drill, self-maintained by the cutting energy. Thus, chips are then evacuated easily. The authors developed a specific tool holder with an adapted axial stiffness. The cutting conditions are chosen to be inside the instable domain and with the chatter phenomenon the lip jump out of the material. The parameters of the Self-Vibrating Drilling Head (SVDH) and the cutting conditions are conditioned by the presence of ploughing effect that dumps the vibrations. The objectives of this paper are (i) to model the cutting and ploughing forces, the dynamical behaviour of the SVDH and the material removal and (ii) to foresee the influence of ploughing on the shape of the chip. A numerical simulator makes it possible to validate the cutting conditions, in particular the influence of the ploughing effect. The simulated results are validated by an experimental protocol.

Keywords: vibratory drilling; self-excited vibration; ploughing; chatter; numerical simulation; deep drilling; toolholder design; axial stiffness; material removal; chip shape; cutting force.

DOI: 10.1504/IJMMM.2008.017623

International Journal of Machining and Machinability of Materials, 2008 Vol.3 No.1/2, pp.34 - 51

Published online: 23 Mar 2008 *

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