Design and Fabrication of a Skew-Typed Longitudinal-Torsional Composite Ultrasonic Vibrator for Titanium Wire Drawing

In this paper, a new longitudinal-torsional (L&T) hybrid vibrator driven by two longitudinal ultrasonic transducers is proposed for ultrasonic-assisted wire drawing. The two identical transducers were vertically installed on the two side surfaces of a transformer, however, with an offset distance (Delta x) and stagger angle (alpha) between their axes. Therefore, the transformer could synthesize and amplify the vibration of the two transducers to produce an L&T composite vibration. Harmonic and transient simulations were performed in ANSYS to investigate the dynamic characteristics and frequency-dependent sensitivity of the vibrator. Delta x and alpha between the transducers were subsequently optimized to maximize the output amplitude. Based on the finite element analysis (FEA) results, a prototype was manufactured with an electrical circuit developed for impedance matching. The vibrator generates an L&T composite vibration with a measured longitudinal amplitude of about 20 mu m when driven by a voltage of 400 Vp-p, 19.597 kHz. The result is consistent with the FEA prediction, which indicates a new method of combining two different forms of ultrasonic vibration.