... Convenient and save labour YP-D21 20Khz Ultrasonic Metal Welding Machine By using the ultrasonic high frequeccy vibration principle, the ... to transfer the metal’s surface. Under condition of producing the heat by the friction and putting apressure to the ... for various hardware and tolls, automobile and motorcycle, machine tools, hardware parts and machine parts, hardware mold, etc.4.Welding/Brazing: ...