In the design of the ultrasonic welding head, the cross-sectional area of the upper end face of the welding head can be determined by the total amplitude amplification ratio (the amplitude amplification ratio of the tapered horn and the amplitude amplification ratio of the welding head). The total amplitude amplification ratio cannot be increased arbitrarily. It is limited by the internal loss of the welding head and the limitation of fatigue. Amplitude amplification is below 30. If the cross-sectional area ratio of the large end of the ultrasonic horn is too large, it will be affected by the transverse vibration of the ultrasonic horn. Typically, in a horn design, the cross-sectional dimension will be less than 1/4λ.
Theoretically, the total amplitude amplification ratio can be designed up to 20-30. In fact, it is necessary to consider the frequency of the ultrasonic welding machine vibration system and its output power and its application level, in order to theoretically design an ultrasonic welding head with a high total amplitude amplification ratio. Therefore, the design of ultrasonic handpieces with high overall amplitude amplification ratios is limited. The most common ultrasonic applications of ultrasonic processing machines, especially high-frequency and low-power (power less than 100W) ultrasonic processing machine systems, ultrasonic plastic welding machine systems are mostly high-power, so they are rare.
The above example shows a 28KHz horn with a big end of 45MM and a small end of 15MM. It is an index welding head design, so M=3; the big end of the ultrasonic welding head is 30MM and the small end is 3MM. It is designed as an exponential ultrasonic welding head, M =10.
Therefore, the shape of the ultrasonic horn is selected when the total amplification ratio of the cone of the vibration part group and the horn is 3×10=30 when the workpiece interferes.
Ultrasonic Plastic Welding machine
Ultrasonic Plastic Welding machine