Focus of this thesis is experimental determining of friction coefficient between cutting tool and workpiece. For this purpose we developed a new open type tribometer, with which we are able to achieve practically the same contact conditions, that occure in real cutting processes. The document presents the design of this tribometer and execution of measurements on 42CrMo4 steel and Ti6Al4V titanium alloy samples, which were in contact with uncoated WC-Co tungsten carbide cutting tool, at different contact and lubrication conditions. The results are compared to those obtained on the closed type tribometer and tool wear analysis for open tribometer is presented.
For used cutting tool a high lubricating ability of emulsion and oil was shown on steel samples, but this ability is highly limited on titanium alloy samples. We found out, that liquid CO2 practically does not have any lubrication properties, because it showed very low lubrication ability on both materials. Two different wear mechanisms appeared on cutting tool at different sample materials; abrasive wear at machining of steel, and adhesive wear at machining of titanium alloy.
Out of friction measurement results we determined an aplication range for both analysed tribometers, in which their usage is sensible, and concluded that for simulation of cutting conditions open tribometer is more suitable.
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