Vibration Welding

VIBRATION WELDING

Also called linear friction welding.

Instead of rotary motion causing frictional heat in friction welding, in vibration welding the movement consists of linear oscillations.

Once molten material has been generated at the interface, vibration is stopped and the parts are aligned and weld consolidates on cooling.

Weld time 1 to 5 sec.

Vibrations applied  100  240 Hz Pressure 1 to 4 n/mm 2

Vibration welding is a kind of friction welding, in which one component is fixed and the mating component is horizontally vibrated while being pressed to another one. As a result,, mating surfaces are melted and then welded. This method is divided into two types according to the mode of vibration, i.e. linear type and orbital type. In the former type, vibration is induced in linear direction, while in the latter type, vibration occurs in the form of a micro circle. Thus, the velocity of vibration is always constant, i.e. not the function of time, in the case of the orbital type, therefore uniform welding is possible. Maximum amplitude is 1.8mm for the linear type and 1.5mm for the orbital type.

1. Vibration welding works through friction and pressure.  

2. The parts to be welded are rubbed against each other under a pressure causing a friction between their surfaces, which generates heat. 

3. The heat results in melting polymer in the joint region. The work pieces are fused together and after a predetermined time the vibration stops. 

4. The polymer molecules are cross-linked when the work pieces cool down, forming a strong joint. 

5. Vibration Welding cycle is very short (milliseconds). 

6. The frequency of acoustic vibrations is in the range 100 to 500 Hz (commonly 100-240 Hz). The amplitude of the vibrations is about 0.02-0.2” (0.5-5 mm). 

Application

1. Vibration Welding is used in automotive and domestic appliance industries.

Material

Most polymers (amorphous, semicrystalline and crystalline) produced by various fabrication methods (Thermoforming, Extrusion, Injection Moulding, Blow moulding, Compression moulding,  Transfer moulding) may be welded by Vibration Welding. 

Main Advantages

1. Very large complex linear joints can be produced at high production rates.

2. Suitable to weld almost all thermoplastics.

3. Oxidizing polymers may be welded; 

4. Easily automated; 

5. High productivity; 

6. Large and complex parts may be welded. 

Disadvantages

1. Relatively expensive equipment; 

2. Minimum rigidity required. 

Examples:

Automobiles parts  Front and rear light assemblies, fuel filter, instrument panel, reservoirs for brake, etc.