Spin Welding / Friction Welding

SPIN WELDING / FRICTION WELDING

1. The generation of frictional heat by two rubbing surfaces is utilized to join materials in the friction welding process.

2. The temperature at the rubbing surfaces raises to beyond the melting point of the plastic material in few seconds.

3. Final forging action ensures the weld is cooled in compression and forms a high integrity joint.

1. The friction welding of thermoplastic (also called spin welding) is based on the same principle as that employed for welding metals. 

2. In this process one of the substrates is fixed, while the other is rotated with a controlled angular velocity. When the parts are pressed together, frictional heat causes the polymer to melt and a weld is created on cooling. 

3. Major welding parameters include rotational speed, friction pressure, forge pressure, weld time and burn off length.

4. Spin welding bonds two cylindrical plastic parts together by frictional heat. 

5. As the actual bond is made through heating and then fusing the mating surfaces, only thermoplastics can be joined by spin welding.  

6. Spin welding is similar to Friction Welding (FRW). 

7. This method is well suited for joining thermoformed container halves. Injection moulded cylindrical parts, etc

MATERIALS

Both amorphous and semi- crystalline thermoplastic can be joined by friction welding

The major welding variables are :-

rotation speed, pressure and cooling time

APPLICATIONS

Spin Welding is used for manufacturing aerosol bottles, floats and other circular parts.

- Plastic floats

- Pipes

- Shafts

- Pressure vessels.

Advantage

1. Reproducibility; 

2. Large parts may be welded; 

3. High quality weld; 

4. Oxidizing polymers may be welded. 

Disadvantage

1. At least one of the parts to be welded should have a circular symmetry; 

2. Minimum rigidity required.