Hybrid moulding gives airbags a boost.
Belgian Tier 1 supplier Quadrant CMS is using plastic/metal hybrid technology to save weight and money in its production of automotive airbag assemblies with integrated lead frames. Production is fully automated and the assembly is being fitted on vehicles from around the world.
The hybrid integrated lead frame fits in with the continuing trend in the car industry to reduce not only weight, but also space for the growing range of increasingly sophisticated safety and entertainment-related devices, especially in and around the steering wheel.
The plastic/metal hybrid moulding has replaced a heavier, more complicated and costly full steel housing for assembly cables which took up more packing space. It was first designed for the Ford Transit van, which is assembled in Turkey. Production began in 2012, but now Ford is introducing it on four other vehicle models in Europe, the US, Brazil and India.
The integrated lead frame activates the horn when the driver presses the airbag cover in the centre of the steering wheel, completing an electric circuit. As such, the module is a safety-critical component, so design and manufacturing needs are very demanding. It is produced by injection moulding a 40 per cent glass fibre reinforced nylon (polyamide) over a pre-coated stamped steel plate.
The housing contains the airbag itself as well as the gas generator, with its main function being to direct the airbag during deployment, by maintaining the form and integrity of the housing. The hybrid structure is created by combining the plastic housing with the lead frame. During development, the metal part within the plastic was shown to induce additional stresses during the deployment. These were eliminated using FEM analysis and design changes.
The over-moulding process is carried out fully automatically in a purpose-built manufacturing cell at the main OCMS plant in Tielt, Belgium. A six-axis robot positions the lead frame precisely into the mould. The reinforced polyamide is then injected around it. The finished product is placed in a neighbouring station that carries out a 100 per cent quality check. Once quality is assured, a conveyer belt transports it downstream.
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|Title Annotation:||SENSORS & DATA AQUISITION: AUTOMOTIVE SAFETY|
|Date:||Jun 1, 2016|
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