Welding characteristics 27kHz, 40kHz, 67kHz and 94kHz ultrasonic plastic welding systems using fundamental and higher resonance frequencies simultaneously -ultrasonic plastic welding using high-frequency vibration systems

摘要

The welding characteristics of 27 kHz, 40 kHz, 67 kHz and 94 kHz ultrasonic plastic welding systems were studied. The 27 kHz, 40 kHz and 67 kHz welding systems were driven at the fundamental and several higher resonance frequencies simultaneously and the welding characteristics were studied. The diameter of the 27 kHz transducer is 40 mm and the diameter of 40 kHz, 67 kHz and that of 94 kHz transducers is 30 mm. At 94 kHz, the diameter is more than half wave length. Required vibration velocities of these systems become smaller as vibration frequency becomes higher. Required vibration velocity of 67 kHz welding system is one third of that of the 27 kHz system. The welding characteristics of lapped 1.0-mm-thick polypropylene sheets were measured in the cases where the 27 kHz, 40 kHz and 67 kHz vibration systems were driven using combined driving voltages of both fundamental and higher resonance frequencies simultaneously. As the fundamental frequency of these welding systems become higher, larger welded area and weld strength were obtained. Using the 94 kHz system, weld strength more than 580 N per one weldment was obtained under vibration velocity 2.7 m/s, welding time 2.5 5 and static pressure 600 kpa.