ULTRASONIC WELDING

GENERAL IDEAS:-

The ultrasonic effect upon the molten metal generates a smaller grain size, giving the metal more strength. Ultrasonic welding combines pressure and high frequency vibration motions to form a solid state bond. The range ultrasonic frequency used in this welding is from 20kHz to 60kHz. This cool, strong weld capable of joining such combination as aluminium to steel, aluminium to tungsten, aluminium to molybdenum and nickel to brass. Ultrasonic welding has also made it possible to join metals with vastly different melting temperatures, making strong rigid joints. Thus many applications previously considered unweldable can now revaluated.

CIRCUIT:-

OPERATION:-

· It consists of an ultrasonic generator, which generates a frequency of 20 kHz to 40 kHz from a supply of 220v/50Hz. The converter transforms the high frequency electric energy produced by the generator into mechanical energy.

· The booster serves as an amplitude transformer for the required amplitude range as well as a general stabilizer for the oscillations of the transducer system. The sonotrode or horn is the working tool of the ultrasonic metal welding.

· The pieces to be welded are clamped between the welding tip called sonotrode and anvil. Both tip and anvil are faced with high-speed steel, since considerable wear can occur at the contacting surface. The process of ultrasonic welding is fairly simple.

· The system that is used to scrub the pieces together consists of four major components. The first of these is the anvil. This is simply a piece of the machine, usually with a replaceable head, that holds one of the components still while the other is rubbed against it..