Tool monitoring of small drills with acoustic emission

Abstract The risk of fracture is higher in the case of small-diameter drills than with any other cutting tool. Analysis of cutting forces or motor current is fundamentally unsuitable for practical applications, owing to the low forces or low sensitivity involved. Suitably-located AE sensors can, however, be used to obtain signals which allow tool wear and fracture to be monitored. The monitoring system realized in the study allows the tool-life dispersions of the drills, which are generally in a ratio higher than 1:3, to be exploited. Tool fractures due to high wear can also be avoided.