Influence of Tool Geometry in Ultrasonic-Assisted Drilling

Methods for advanced manufacturing enabling high performance cutting contribute to sustainability in terms of reduced energy and resource consumption. Ultrasonic assistance is a known approach to improve cutting processes for example through reduced forces, tool wear and burr formation as well as enhanced chip breaking behavior. Regarding ultrasonic-assisted drilling, shaft geometry of the drilling tool affects the vibration characteristics and therefore the fundamental effects and process properties. This paper investigates the influence of tools with straight-flute and twisted shafts on the shape of ultrasonic vibration. A kinematic process analysis deduces the change of cutting mechanism. Experimental test series in EN AW-7075 are designed according to process scenarios with intermittent and continuous cutting conditions. The evaluation includes chip size and process forces to show the influence of process parameters and tool geometry as well as the potentials of ultrasonic-assisted drilling.