Design of horn for rotary ultrasonic machining using the finite element method

The cutting performance of an ultrasonic machining machine (USM) depends primarily on the ability of the design of the acoustic horn (also known as concentrator or tool holder). A horn is a waveguide-focusing device with a cross-sectional area that decreases from the transducer end to the toe end. It amplifies the input amplitude of vibrations so that at the output end the amplitude is sufficiently large for machining. In the present work, a finite element method (FEM) design procedure has been developed for the design of a horn for rotary ultrasonic machining (RUM). The double conical horn shape has taken as a domain with a hole at the tip for the cooling purpose. The analysis of the various stress components in the horn domain has been studied. The stresses at the middle of the horn are found to be maximum but it is within the allowable stress of the horn material due to the sudden change in the area of the horn. The stresses on the horn for various frequencies are also studied and concluded that at resonance condition the stress is minimum.