What is Ultrasonic Welding Process (USW) ? Full Explanation with Advantages, Dis-Advantages and Applications.

 Introduction:

Ultrasonic welding is a welding process during which ultrasonic waves or vibrations are accustomed to generate heat for welding. Ultrasonic means those vibration waves which have a frequency above the normal hearing range. It is about 20000 to 30000 Hz. It is a solid-state welding process. Solid-state welding is a welding process during which no external heat is required for joining the workpiece.

Main Working Principle of Ultrasonic Welding:

It deals with the key rule of energy of ultrasonic waves. Ultrasonic vibration makes dynamic shear pressure between the contacts of two workpieces. Because of nearby plastic twisting and warmth created because of erosion between contact surfaces, the joint arrangement will happen at the interface.

Working  process in detail of Ultrasonic Welding:

At the start, a high-frequency current passes through a piezoelectric transducer. This transducer converts the high-frequency electrical signals into mechanical vibration.

This vibration further supplied to the booster which amplifies its frequency.

The enhanced high-frequency vibration goes through the horn which is in touch with the welding plate.

This welding creates a lap joint. One plant of the weld is fixed into the installation and the other one is in direct contact with the horn. These holding plates are fixed under moderate tension power.

The horn supplies high-recurrence mechanical vibration to the welding plate.

Due to this vibration, oscillation shear force act at the interface between welding plates which results in elastoplastic deformation at the interface.

It also creates a localized temperature rise due to mechanical force and friction. This heat helps in plastic distortion at the interface and makes a solid joint without dissolving the workpiece or utilizing filler metal.

Fig. Ultrasonic Welding

Equipment of USW:

Ultrasonic welding consisting of the following equipment:

• Power Supply: The ultrasonic welding needs a high recurrence and high voltage power supply. This force is required by the transducer to produce vibrations.

• Transducer: A transducer is a device that can convert a high-frequency electric signal into high-frequency mechanical vibration. This is connected with the welding head. The converter or piezoelectric transducer utilized in this welding cycle.

• Booster and Horn: The mechanical vibration made by the transducer is provided to the promoter which enhances this vibration and supply to the horn. Horn is a gadget that provisions this intensified vibration to the welding plates.

• Fixture or clamping devices: This gadget is fundamental in ultrasonic welding. This uses either electrical, pressure-driven, pneumatic, or mechanical energy to hold the plates into the craving area.

Advantages of USW:

• This welding can be handily mechanized and quick.
• This produces high strong joint without applying outer warmth.
• This is clean and provides a good surface finish after welding.
• The ultrasonic process used to weld a wide variety of dissimilar metals.
• It does not develop high heat so there is no chance of expelling molten metal from the joint.

Disadvantages of USW:

• It does not weld thick harder metal. The thickness of welds about 2.6 mm for aluminum.
• Tooling cost for fixtures is high and they also need a special design.
• The vibration generates through a transducer, can damage electronic components.

Applications of USW:

• This welding is used in the fabrication of nuclear reactor components.
• It is used in the automotive industry for keys, headlamp parts, buttons,s, and switches, etc.
• Ultrasonic is used in electronic industries like armada winding, switches, etc.
• This is a perfect welding measure so it is utilized in clinical enterprises to make parts like channels, veils, and so forth.