Multi-functional sheet metal fastener saves costs

The extreme versatility of a multi-functional sheet metal fastener is realising significant build quality benefits and cost savings of up to $0.50 per car.

The extreme versatility of Profil UK's newest multi-functional sheet metal fastener is being put to good use by Ford in the assembly of its Fiesta, Ka and new generation Focus models.

Up to 6 off Profil RSN 'top hat' nuts are installed in each vehicle, providing high-strength, water-tight mountings for after-market roof racks - as well as significant build quality benefits and cost savings of up to $0.50 per car.

The new Profil nuts have a completely sealed end and are mounted in the vehicle's roof cant rails at the body-in-white stage.

Their ability to provide flush-mounted class 8 EN20898 steel threads with exceptionally high torque and pull out resistance is backed by installation rates that are at least ten times faster than those of welded fasteners.

A further benefit of the Profil system is that each nut is consistently positioned to an accuracy of +0.2mm - approximately three times superior to that of welded equivalents.

Indeed, this inherent precision is a central factor in the vehicles' overall assembly process.

Each of the new fasteners incorporates a press fit nylon 6,6 plug, which in turn, has a 'Posidriv' screw head form moulded into its exposed end.

The centres of these cross head profiles are used as primary location points by the laser guided robots employed to weld the body panels together.

A 2mm thickness of sealant is subsequently applied to the spot welded roof seams - and the installed 'top hat' nuts - to ensure water proofing of the body assembly prior to painting.

Throughout both these operations, the fastener's plastic plug acts as a highly effective thread protector.

During final assembly the complete installation is hidden by a plastic finisher strip, which is only removed when the roof rack is fitted.

A further novel feature of the multi-function fastener is that the heat of the paint oven softens the nylon plug sufficiently for it to take up the form of the bore's internal threads.

As a result, it can be easily unscrewed from the installed steel nut, ready to accept the roof rack's mounting bolts.

According to Profil UK's Adrian Ellis, "The simplicity of new RSN 'top hat' nut belies the painstaking effort that has gone into developing the product to fulfil all of Ford's requirements.

The installed fasteners provide high strength, precisely positioned, water-proof, steel threaded anchorage points as part of the normal assembly process.

They not only eliminate the risk of bodywork or paint damage caused by the installation of alternative products such as rivet nuts, but also the costs of separate off-line manual or welding operations.

Available in M6, M8 and M10 variants, the new Profil RSN 'top hat' nuts are also being evaluated by other leading automotive manufacturers for further 'wet area' fastening applications, including the provision of bonnet, boot lid and tailgate mounting anchorage points.

About Profil UK - based in Coalville, Leicestershire, Profil UK draws on more than 30 years experience in the development and application of pierce fastening technology.

The company offers a comprehensive range of fastener styles and installation equipment - all backed by ISO 9001 certification - and is a principal supplier to customers throughout the automotive, domestic appliance and sheet metal fabrication sectors.

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