... low, oxidation or plating can be welded.4, the welding time is short, without any flux, gas, solder.5, ... be water, gas-tight.ULTRASONIC THEORY Ultrasonic metal welding machine uses ultrasonic frequency vibration principle to change ultrasonic vibration ... of the formation of the new equipment.FEATURES Microcomputer control, electronic tuning frequency, LCD display, power adjustable, operate simple, run ...