Maximization of the effective impulse delivered by a high-frequency/low-frequency planetary drill tool

Harkness, P. , Lucas, M. and Cardoni, A. (2011) Maximization of the effective impulse delivered by a high-frequency/low-frequency planetary drill tool. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 58(11), pp. 2387-2396. (doi: 10.1109/TUFFC.2011.2096)

Abstract

Ultrasonic tools are used for a variety of cutting applications in surgery and the food industry, but when they are applied to harder materials, such as rock, their cutting performance declines because of the low effective impulse delivered by each vibration cycle. To overcome this problem, a technique known as high-frequency/low-frequency (or alternatively, ultrasonic/sonic) drilling is employed. In this approach, an ultrasonic step-horn is used to deliver an impulse to a free mass which subsequently moves toward a drilling bit, delivering the impulse on contact. The free mass then rebounds to complete the cycle. The horn has time between impacts to build significant vibration amplitude and thus delivers a much larger impulse to the free mass than could be delivered if it were applied directly to the target. To maximize the impulse delivered to the target by the cutting bit, both the momentum transfer from the ultrasonic horn to the free mass and the dynamics of the horn/free mass/cutting bit stack must be optimized. This paper uses finite element techniques to optimize the ultrasonic horns and numerical propagation of the stack dynamics to maximize the delivered effective impulse, validated in both cases by extensive experimental analysis.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cardoni, Dr Andrea and Lucas, Professor Margaret and Harkness, Professor Patrick
• Authors: Harkness, P., Lucas, M., and Cardoni, A.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
• ISSN: 0885-3010
• ISSN (Online): 1525-8955