Monitoring tool wear during turning process using surface strain sensor

Monitoring tool wear using various sensors, such as current, force, temperature, and vibration sensors, is critical for improving machining efficiency. This study proposes the use of surface strain sensor to monitor tool wear during the turning process. It is found that the longitudinal strain on the top surface exceed that of the side surface by approximately 28%. The optimal placement of the surface strain sensor is determined to be along the axial direction on the top surface of tool bar. Then, the turning experiments were conducted to verify the sensor’s performance by comparing the strain and force signals. The results show that the strain and force waveforms are completely synchronous in both the time and frequency domains. Furthermore, the strain signal curve, which varies with machining parameters, completely coincides with the force signal curve. Due to its shorter transfer path and reduced external interference, the strain signal demonstrates better tool wear characterisation capabilities than force signal. Overall, these findings provide a guideline for applying surface strain sensors in the intelligent monitoring of tool wear progression.