New, recyclable thermostat housing brings 20 per cent cost reduction and 30 per cent weight saving

New, recyclable thermostat housing brings 20 per cent cost reduction and 30 per cent weight saving

Keyword: Plastics

A fully recyclable thermostat housing, offering a possible 20 per cent cost reduction and a 30 per cent weight reduction, has been developed by Siemens Automotive, Air Fuel Module Division (see Plate 1). Compared with the existing design, the new unit is easier to manufacture, has fewer components and can be recycled at end of vehicle life. The first application of the new housing will be on revised Ford Zetec and Sigma engines.

Thermostat housing have traditionally been manufactured from a thermosetting phenolic resin with machined metal compression inserts. Because thermosets cannot be melted, neither the unit nor any manufacturing scrap could be recycled. Siemens' solution is to redesign the housing using a recyclable 30 per cent glass-filled Nylon 66, developed by Bayer, which provides a level of resistance to heat and glycol (present in antifreeze) previously not available in a thermoplastic.

 Plate 1 The new recyclable thermostat housing from Siemens

As well as allowing end of life recycling, as with all new Siemens automotive components, the new material has also allowed the introduction of several other innovations. "To create the complex internal geometry, we had previously used the lost core technique to manufacture the unit as a single moulding",explains Jim Tibbetts, Engineering Manager at Siemens Automotive's Telford (UK)plant. "With the new material, we can use an automated vibration welding process to fabricate it from two low-cost injection mouldings."

Siemens has also taken the opportunity to replace the machined compression limiter inserts with low-cost rolled steel inserts and to integrate several other fittings into the body mouldings. Threaded inserts have been eliminated through the adoption of push-fit sensors, further reducing costs and simplifying assembly at the vehicle plant.

"The result of our redesign will be substantial savings for our customers",says Tibbetts. "It is a good example of the way Siemens is looking for cost-down opportunities in every area of our operations.

"The redesign work completed by Siemens is evidence of the successful relationship between Ford and its leading suppliers, working together to reduce costs and to help the environment", concludes Bob Wright, of Ford Powertrain purchasing in the UK.

Enquiries: Bryonie Wall, Sales and Marketing, UK and Northern Europe, Siemens Automotive Systems Ltd, Halesfield 25, Telford, Shropshire TF7 4LP, UK. Tel: +44(0)1952 683600; Fax: +44 (0)1952 580626; E-mail: bryonie.wall@rbg2.siemens.de