In-situ characterization of tool temperatures using in-tool integrated thermoresistive thin-film sensors

Metal cutting is characterized by high temperatures at the tool-workpiece interface. Although valuable information could be provided by the temperature values, their direct measurement still presents a challenge due to the high contact pressure and the inaccessibility of the process kinematic. In this research work, the current state of thin-film sensors for measuring temperatures on the chip-tool interface has been analyzed with a focus on the measuring phenomena: thermoelectricity and thermoresistivity. Thin-film sensors placed on the cutting tools in or close to the tool-chip contact area are expected to obtain accurate temperature information at the expense of a short lifetime. New insights into thin-film sensors manufacturing, design and calibration are presented, and a new concept of a three-point thermoresistive thin-film sensor is proposed. During orthogonal cutting tests the workpiece deformations were measured through high-speed imaging and the process temperatures were measured with thin-film sensors. In order to validate the temperatures and to obtain the temperature distribution on the cutting edge, Finite Element simulations were carried out. Finally, the potential of using cutting tools with integrated thin-film sensors for in-situ characterization is investigated and a statement for its limitations and potential applications is given

Dünnschichtsensorik zur ortsauflösenden Temperaturmessung in geschmierten Wälzkontakten

The knowledge of the contact temperature in lubricated rolling contacts is of crucial importance. The scuffing load capacity for gears, e.g. is based on the contact temperature. While the measurement of the temperature in the lubricating gap with elasto-hydrodynamic lubrication by means of thin-film sensors has already been described several times, this has not yet been done for mixed lubrication. In the following, the authors give further information to the experimental setup and first results for measuring the contact temperature under mixed lubrication