Design of a circular hollow ultrasonic horn for USM using finite element analysis

Abstract

Ultrasonic machining (USM) is one of the non-conventional techniques extensively used in industries for machining hard and brittle materials. The USM operates on a very high frequency of around 20–40 kHz and the tool which vibrates gives amplitude of around 5 μm. However, in order to achieve proper machining, the tool must have an amplitude of around 10–100 μm. Therefore, the ultrasonic horn magnifies the amplitude of vibrations from the transducer end to the tool end. The magnification factor for the amplitude of vibration is dependent on the design of the ultrasonic horn. In the present work, an ultrasonic circular hollow horn is designed for USM using finite element analysis (FEA) to match the required performance of a conventional ultrasonic machine. Firstly, the profile of the horn is determined using the general differential equation for generating the 3D model. The natural frequencies and the mode shapes are determined by performing the modal analysis. Subsequently, the feasibility of the design is checked by performing the harmonic response analysis to determine the magnification factor and the equivalent stress experienced by the horn. Finally, the suggested design of ultrasonic horn is validated by comparing with the existing design of ultrasonic horns. The study indicates the dominance of the suggested design over other designs, while maintaining the stress value well below the limit of endurance for the horn material. Hence, a circular hollow ultrasonic horn is designed using FEA, which can be used for USM in industrial applications.