(Received November 13, 1984)
Ultrasonic welding of a ring shape weldment with two vibration systems is proposed and studied. The vibration directions of the upper and lower welding tips are crossed at a right angle. The upper and lower vibration systems are driven by independent controllers and 2 kW and 5 kW power amplifiers. Specimens used were 18 mm diameter rings with a flange and circular plates of anticorrosion aluminum alloy. Using the welding system with two vibration systems, these specimens were successfully welded with about an 18 mm diameter and 0.5 mm to 1 mm wide ring shape weldment.