Judgment of Tool Life in Drilling Using Acoustic Emission

We investigate the use of a new sensor device for detection of acoustic emission (AE) through fluid, for a drilling machine. Within the industry there has always been the need for a practical application of the AE sensor through fluid to detect the cutting-process-related signals from the tool side. A mounting apparatus which enables the sensor to be fixed close to the rotating cutting tool has been developed to meet this need. Thus, there is now a more practical method for detecting the tool breakage and tool wear of twist drills. Judgment of tool life by a quantitative method using the ratio of the event count to oscillation count per unit time was carried out very accurately. From our experiments, the evaluation method for quantifying tool life using the ratio of the event count to oscillation count was found to be effective.