Quadrant CMS has acted as development partner for Autoliv, a worldwide leader in seatbelts and airbags, in the production of systems critical polymer-based parts and components for safety systems for over 30 years. During this time, Quadrant CMS’ ability to integrate its tooling and processing knowledge into the highly-automated production of creatively-designed parts has been appreciated by the customer. For this particular airbag housing, four metal bushes – used to secure the airbag housing in the dashboard – are moulded into the housing.

In order to fulfil requirements for the cost-effective and efficient production of a large number of housings per year, Quadrant CMS installed a brand-new production line for this application at its plant in Tielt, which included an automatic feeding system for the bushings, as well as robots for their insertion and the release of the moulded parts. The subsequent assembly of the moulded parts into a complete airbag housing module, and the ability to co-develop the housing in a 3D CAD environment, were further Quadrant CMS contributions to the project.

By adopting polyamide for the airbag housing’s manufacture, a number of advantages could be gained, as Wim Vlaeminck from Quadrant CMS explains: “For any car, weight-saving is critically important – and in this case the weight of the housing has been reduced from 750 grams to 370 grams. But using injection-moulded polyamide to replace die-stamped steel brings other advantages as well. Though the basic raw material may cost more per kilo, a moulded part is faster, easier and less expensive to produce, while the material can still be recycled at the end of its life cycle.”

Airbags are critical systems in vehicle safety which, by essence of their purpose, are required to function under severe conditions. It takes an airbag about 60 milliseconds to inflate - causing high impact loadings on the housing. Yet it is imperative to the airbag’s function – and thus passenger safety – that the housing remains intact and anchored firmly to the dashboard.

In contrast to other vehicle parts – on the exterior and in the engine compartment – metal replacement by polymer based components is comparatively new for safety devices. Yet the rewards of improved fuel efficiency through reduced vehicle weight continue to drive its adoption. For this particular airbag housing, the OEM expressed initial concerns regarding the part’s ability to comply with the demanding requirements of the application. Hence a metal housing was developed and tested in parallel to the polyamide version produced by Quadrant CMS. Consequently Volkswagen concerns were allayed following prototype testing, and the polyamide housing was adopted as a running change in the production of the current models.

For testing purposes a fully functional single-cavity prototype mould was produced by Quadrant CMS using three-dimensional mould design, FEA analysis and virtual testing, as it was required to deliver parts as close as possible to those from serial production. These prototypes were used for testing at the Autoliv facilities, including stress and impact tests in temperatures ranging from -35°C to 85°C. Ultimately only small modifications had to be made to the mould, to enhance part performance even further.

With the successful adoption of the polyamide housing in vehicles based on the Volkswagen Golf platform, both Quadrant CMS and Autoliv are confident of extending the application to other models in the coming period.