Influence of electric circuit of cutting system on tool wear

摘要

This study was performed with the purpose of experimentally establishing the dependence of thermoelectric current flowing between a tool and workpiece on the configuration of a cutting system, the cutting conditions being the same, and of clarifying the correlation between thermoelectric current and tool wear, by using a stable cutting system and an unstable cutting system. The following conclusions were made in the study. (1) The resistance of the headstock, including an external circuit of an ordinary cutting system, is different for different machine tools and in the case of using the same machine tools, its influence on the feed is stronger than on the depth of cut. (2) The resistance of tailstock, including an external circuit of an ordinary cutting system, depends on the type of the center. (3) The combined internal resistance of tool-chip and workpiece-tool major flank amounts to 0.5-2 mΩ and when no oxidation film is formed, its value is close to that of the steel-to-steel contact resistance. (4) When using an insulated cutting system in which a thermoelectric current does not flow between tool and workpiece, the tool life is maximal and is by about three times longer than the tool life in the case of using an ordinary cutting system with just a small thermoelectric current flow due to the high resistance of the external circuit.