The determination of ploughing force and its influence on material properties in metal cutting

The ploughing force induced by cutting edge radius and/or tool flank wear is an important factor in tool wear monitoring, material flow stress estimation, chip formation mechanisms, part surface integrity, and finite element modeling of metal cutting. In the literature, the ploughing force has been estimated based on the cyclic force after the end of steady-state cutting. However, the cyclic force does not consistently appear in many cutting conditions. In this paper, the ploughing force is estimated by the extrapolation method, to zero uncut chip thickness, and used for correcting the estimate of material flow stress. The corrected flow stresses show negative strain rate sensitivity, while the flow stresses based on the measured raw force data show positive strain rate. The corrected flow stresses appear to be more uniform when plotted against the uncut chip thickness. In addition, the corrected flow stresses agree with the compression test data by appropriate extrapolation. Therefore, the extrapolation approach seems to be acceptable to estimate ploughing force in the absence of the cyclic force. (C) 2004 Elsevier B.V. All rights reserved.