Investigations into the cutting characteristics of CCS type disc cutters and the comparison between experimental, theoretical and empirical force estimations

A new model is suggested in this study to predict normal and rolling forces acting on CCS type disc cutters by modifying an empirical model developed by Bilgin (1977) for V type disc cutters, which was based on the theoretical model developed by Roxborough and Phillips (1975). The suggested model is based on the fact that V type disc cutters are manufactured with some certain edge radius as a pre-blunting to reduce the premature tool breakages. Giving an edge radius to a sharp V type disc cutter generates a disc tip (edge) profile similar to the edges of CCS type disc cutters. The predictive parameters of the suggested model are disc diameter, edge radius (or half of tip width) as a function of edge angle, cutter penetration and rock uniaxial compressive strength. Results of the full scale linear cutting experiments previously performed by the authors of this study on three different rock samples in relieved (interactive) and unrelieved (uninteractive) cutting modes are used to validate the predictive ability of the suggested model. Some additional experimental data from the recent literature are also used for this purpose. Two different constant cross section (CCS) disc cutters having 330 and 432 mm diameters and 12 and 18 mm tip widths, respectively, are used in the cutting experiments performed by the authors of this study and different cutter diameters and tip widths are used by the data taken from the literature. The results indicate that the suggested empirical model predicts reliably the normal forces with a slight overestimation, although the rolling force predictions show some scatter. It is also indicated that a theoretical model developed by Rostami and Ozdemir (1993) for CCS type disc cutters predicts normal forces with a very high reliability, although there is some scatter on predictions of the rolling force. Prediction of rolling force should be analyzed in more detail in future studies. (C) 2014 Elsevier Ltd. All rights reserved.