Ultrasonic welding is a cold-joining process(I.e.,solid- state welding).In this case ,a bond is produced by ultrasonic vibratory energy in the weld region.The equipment necessary for ultrasonic welding is shown in fig.It includes a transducer,a velocity transformer with a sonotrode tip and a suitable anvil.The prob induces lateral vibrations on workpieces such that surface films are broken and bond results due to slip between clean surfaces under pressure.The operation should be stopped as soon as weld is complete. This is to avoid bonding of prob with upper workpiece.
1) Absence of generated heat.
2) Dissimilar metals can be joined.
3) No oxidation and distortion
4) The welding time is only about one second or less.
1) The maximum thickness is limited to 0.3 to 2.5mm
The ultrasonic welding is employed for spot welding and seam welding of thin strips or foils.It can also be used for welding aluminium up to 2.5mm thick.The process is mostly used for welding dissimilar metals such as aluminium to stainless steel and aluminum to copper l.It has been used for refractory metals such as titanium and zirconium.