Configuration of a 30-mm-diameter 94 kHz ultrasonic longitudinal vibration system for plastic welding

Vibration and welding characteristics of a 94 kHz ultrasonic plastic welding system are studied. The 94 kHz ultrasonic plastic welding system consists of a 30-mm-diameter bolt-clamped Langevin type PZT longitudinal transducers with four PZT rings, a stepped horn (vibration transform ratio N=3.0) with a supporting flange at a nodal position and a catenoidal horn (N=3.13) with a 8-mm-diameter welding tip. Maximum vibration velocity of the welding is 3.2 m/s (peak-to-zero value) at loaded condition. Welding characteristics of 1.0-mm-thick polypropylene sheet specimens using the 94 kHz welding system are studied. Using the 94 kHz system, weld strength more than 370 N per one welded area was obtained at vibration velocity 2.7 m/s/sub p-0/, welding time 0.8 s and static pressure 600 kPa.