... gas, solder.5, no welding sparks, environmental protection and safety.Local advantages:1, using phase-locked PLL frequency automatic tracking ... can be water, gas-tight.ULTRASONIC THEORY Ultrasonic metal welding machine uses ultrasonic frequency vibration principle to change ultrasonic vibration ... , use of safe, similar to metal welding, able to implement a single point or multi-point non-ferrous metal ...