Ultrasonic complex vibration welding system using a one-dimensional longitudinal-torsional vibration converter with large welding tips

摘要

Vibration and welding characteristics of complex vibration ultrasonic welding systems of 27 kHz and 40kHz are studied. Complex vibration systems which have elliptical to circular or rectangular to square locus are effective for ultrasonic welding of various specimens including the same and different metal specimens, and for direct welding of semiconductor tips of IC, LSI (flip-tip joining) and packaging of various electronic devices. The complex vibration systems consist of an one-dimensional longitudinal-torsional vibration converter with slitted part, a stepped horn and a longitudinal vibration transducer (a bolt-clamped Langevin type PZT transducer). Four welding tips arc made at the circumference of a free end of the complex vibration converters 24 or 20 mm in diameter. The complex vibration welding tips of 27 kHz and 40 kHz have enough area for various welding specimens. The vibration locus of the welding tip was measured using two laser Doppler vibrometers. Aluminum plate specimens of 0.3 to 1.0 mm thickness were successfully joined with weld strengths almost equal to aluminum specimen strength, and independent to the angle between welding tip vibration and specimen directions. Required vibration amplitude of 40 kHz is smaller than that of 27 kHz.