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Enhanced sealing method for curtain airbags...using laser welding

Connect, no. 134, January/February 2005, p.1

Image courtesy of Autoliv
Image courtesy of Autoliv

Laser welding of textiles, using a TWI invention, has found a unique application in airbag manufacture.

As part of a DTI funded collaborative project, TWI has teamed up with INVISTA and several other partners to develop procedures for laser welding of textiles using Clearweld® consumables.

The airbag manufacture is an important application of nylon fibre produced by INVISTA. They are made using woven nylon 6,6 fabric and typically have stitched seams or are woven in one piece using specialised looms.

Airbags were initially introduced for the protection of driver and front passenger in the event of a forward collision.

Developments in automotive safety have led to the introduction of airbags mounted in the sides of the seats and in the roof above the doors, known as curtain airbags. These provide protection from side impacts and during multiple rollover events.

However, rollover events in particular require the curtain bags to stay inflated for at least 10 seconds to offer effective protection. This places additional requirements on the sealing of the seams, and adds extra steps to the manufacturing process.

TWI has developed laser welding techniques for textiles which provide a rapid automated method for sealing a seam against gas or fluid leakage, whilst retaining the outward appearance, feel and flexibility of the fabric. Airbag demonstrator samples were prepared and tested. The results from these trials proved promising, with the welded seams showing leak versus pressure performance within the range of that achieved using conventionally sealed seams.

The highly automated welding procedure offers the potential for cost savings by reducing the time and number of steps involved in airbag manufacture. The Clearweld® process was invented at TWI and has been commercialised by the Gentex Corporation (please see for details).

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