Cutting temperature measurement using a novel near-infrared two-color pyrometer under dry and wet cutting of Ti‐6Al‐4V alloy

Due to the poor thermal properties of titanium alloys, heat generated and accumulated in the cutting area significantly affects tool life and workpiece quality. Although some methods have been proposed to measure the cutting temperature during machining titanium alloys, there still exist disadvantages including low spatial-temporal resolution, low measuring accuracy, restricted usage environment, etc. In this paper, a novel near-infrared two-color pyrometer system is developed and applied to measure the cutting zone temperature under dry and wet cutting of Ti‐6Al‐4V alloy. The developed pyrometer can eliminate the emissivity effect and shows a good linear relationship between the output signal ratio and the calibrated temperature. Meanwhile, the developed pyrometer exhibits good dynamic response and high measuring accuracy when measuring tool edge temperature and chip temperature in dry cutting conditions. In addition, a reliable sealing for cutter assembly is developed to overcome the influence of cutting fluid on the optic-fiber probe and the developed pyrometer can measure the tool edge temperature quickly and accurately in wet cutting conditions. In summary, the novel near-infrared two-color pyrometer system is validated to be quick responsiveness, high measuring accuracy, and good working stability when monitoring the cutting zone temperature under dry and wet cutting of Ti‐6Al‐4V alloy.