Plastic chassis heralds changes in auto materials

Edited by the Engineeringtalk editorial team Jun 8, 2001

The development of the 'Smart' car, the first car with an all-plastic chassis, will have a big impact on the materials used in future generations of motor vehicles, says a Frost and Sullivan analyst

The development of the 'Smart' car, the first car with an all-plastic chassis, represents a revolution in the automotive industry in almost every respect.

From design through to assembly, this car is a unique concept that could have big implications for future generations of motor vehicles and the materials used to make them.

David Platt, Senior Plastics Industry Analyst with Frost and Sullivan explores the details in this article from chemicals.frost.com.

The first 'Smart' car came off the production lines in late 1997 at a factory in Hambach, France, near the German border.

The joint owners of the Micro Compact Car project, Mercedes-Benz and Swiss company SMH, the makers of Swatch watches, plan for production of 200,000 vehicles in 2001.

There are three basic models on offer, known as Pure, Pulse and Passion, which all use a Mercedes-Benz 3-cylinder, 600cc turbo engine.

There are also plans to introduce a Roadster model in the near future.

The 'Smart' car can manage 50-60mpg with a top speed of 87mph.

The manufacture and assembly of the 'Smart' car differs in many ways from other vehicles currently on the road.

First of all, the production site itself reflects a new principle.

Unlike existing systems, in which parts are shipped from far away, Smart components will all be produced and assembled under one roof.

A radial assembly axis crosslinks system suppliers, including plastic chassis producer Dynamit Nobel Kunststoff GmbH, which will injection mould the large parts using an initial ten machines with a clamping force of 1,300-4,000 t.

Also, because of the Smart plant's rational set-up, the entire car can be produced in a record four hours and dismantled in two hours.

The 'Smart' car is also the first vehicle to use plastics for the chassis and body panels.

GE Plastics Xenoy PC/PBT blend is the material chosen for manufacture of these parts.

The sophisticated construction developed by Dynamit Nobel in co-operation with Ymos, facilitates the use of so-called 'hang on' parts.

As the chassis is bolted rather than welded onto the steel frame, parts such as fenders can be switched for those of a different colour, for example.

Owners can also clip in new seats and seat covers, door linings or cockpit elements to reflect different outfits or tastes.

This technology breakthrough is known as Customised Bodypanel System (CBS).

Along with the body system, Dynamit Nobel is also supplying a number of visible and invisible car components, including parts of the door- and wheel cladding, special attachment clamps for the chassis and a "crashbox" for fore and aft, which absorbs energy in the event of a minor collision.

The use of PC/PBT blends for manufacture of the chassis and body panels of the 'Smart' car should spark increased interest in engineering plastics for automotive applications.

This car has demonstrated that the replacement of metal with body parts made of engineering thermoplastics benefits car manufacturers as well as the motorist.

Manufacturers can reduce assembly time and tooling costs by using the new plastic processing technologies.

At the same time, the significant weight reduction afforded by plastic body parts leads to lower fuel consumption for the motorist.

Finally, the revolutionary design of the 'Smart' car means that at end-of-life around ninety percent of the car is recyclable, a significant improvement on what is currently being achieved.

Following the introduction of the EU End-of-Life Vehicle directive in 2000, recycling aspects will in future receive much greater prominence by car designers and manufacturers.