MATERIALS/PROCESSES

Glass fibre gives nylon brush-off

A glass fibre reinforced resin is replacing carbon-filled nylon material to cut costs and improve the cleaning efficiency of Rowenta electric toothbrushes.

Rowenta switched to Isoplast polyurethane resin to mould a part in the toothbrush head that controls oscillation. Small but critical improvements can be achieved by choosing the right material. Isoplast resin combines toughness and resistance to impact with high load carrying capacity. And it is said to be easy to mould, requiring low clamping pressures so you get smoother parts with less grain.

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* A German maker of cylinder head gaskets has developed a formulation which combines graphite and composite materials to produce a tough, high temperature product resistant to chemicals.

Frenzelit, which claims to have aroud 10% of the market, believes its developmement will boost a stagnating market suffering from low R&D spend.

It also says that the technology, using DuPont’s carbon fibre composite Kevlar to counter the graphite’s brittleness, is more cost-effective than gaskets made from steel.

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* Bladder technology is of growing importance to sports equipment as well as traditional engineering equipment makers.

Bladders provide buoyancy compensation in scuba diving vests.

In newer designs the vest does not have a separate bladder so the outer skin material can suffer additional stress. A new poly film could help. Properties include the ability to recover from up to eight times elongation, high tensile strength, abrasion and chemical resistance and what is claimed to be exceptional flex fatigue resistance.

Engineering applications include bellows to protect hydraulic rams.

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* North Carolina in the US tube maker Romac turned to utility stainless steel supplier Cromweld for a material that provides essential corrosion properties but forms as easily as mild steel.

The solution is a stainless steel called 3CR12 which, with its fine-grained microstructure, bends easily and welds well.

Romac tubes range in size from 0.5 to 5in diameter with wall thicknesses from 0.028 to 0.180in.

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