MATERIALS-PROCESSES

Ford cars take recycled plastics on board

Recycled bottles and other plastics are providing the Ford Motor Company with a ready source of material for use in new cars.

On some models sold in North America the company has outlawed the use of virgin plastics on heating and ventilation doors. This is a demanding application requiring parts measuring up to 6 wide and 7 long to maintain strength and dimensional stability at high temperatures over the life of the vehicle.

To meet its specification, Ford chose Impet R supplied by Hoechst technical polymers subsidiary Ticona. This is a 45% glass reinforced thermoplastic polyester rated to 230 C under a load of 1.66MPa.

The recycled substitute performs better than the virgin material in some areas. It retains flatness and dimensional stability to tighter tolerances because of its ‘heat history’ which reduces viscosity and improves glass fibre dispersion. The material’s processing capability is said to be as good as the virgin reinforced polymer.

Moulded-in detail includes a snap fit for the crank arm which rotates the doors. The specification calls for a low insertion/high extraction force. To meet it, the moulding tolerance on the crank arm is +/-0.3mm.

{{TICONA211 ON EXPRESS ENQUIRY CARD}}

Plastics have replaced stainless steel as a gear material in chemical industry pumps.

The Victrex Peek polymer chosen by Northern Pump for its Dura machines exhibits excellent chemical, corrosion and wear resistance, says the supplier.

Moisture absorption that would swell the gears and seize the pump, a problem with some plastics, is low. The polymer also overcomes a problem experienced with 300 series stainless steel that of ‘galling’ in the absence of lubrication.

In this situation made worse by the low lubricity of the chemicals being pumped steel gears self-destruct.

The angled helical gear form imposes tough moulding requirements.

{{VICTREX PEEK212 ON EXPRESS ENQUIRY CARD}}

Stainless steel and aluminium tubing from UK supplier TW Metals is used in the Zeppelin NT airship built in Germany, helping to halve the weight of the structure compared with previous rigid airships and increase the economic payload.

Zeppelin NT is designed to carry 14 people cruising at 70mph. It is 75m long, 14.2m in diameter and has a total volume of 8225m3. The lifting gas is helium.

{{TW METALS213 ON EXPRESS ENQUIRY CARD}}