Where the growth is in lawn & garden.

OPPORTUNITY: Mower Decks

GROWTH OUTLOOK: The lawn and garden equipment market is growing at about 5% a year and accounts for about 70 million lb of plastic, according to BASF Corp., Mt. Olive, N.J. With the emphasis on weight savings in lawn and garden tools, power-mower decks are an attractive opportunity to add to that total, say several resin suppliers. So far, there are only a few plastic mower decks on the market. Although the low cost of stamped steel or cast aluminum may make plastic mower decks a tough sell to DEMs, weight savings can count for a lot in cordless mowers that carry heavy batteries, suggests senior applications engineer Jeff Boyle of GE Plastics, Pittsfield, Mass.

MATERIALS USED: Plastics must have good weatherability and resist gasoline. PC/polyester blends are good candidates, as are ABS, ASA, and nylon.

PROCESSING SKILLS: Coinjection molding requires additional equipment and tooling costs, but it can help bring down part cost, as well as beef up structural properties, according to Peter Schege, applications development engineer in the styrene copolymers group of BASF Corp.

One example is an 8-lb test part being developed by injection molder Bemis Manufacturing Co., Sheboygan Falls, Wis. It consists of an outer layer of GE's Xenoy PC/polyester over a core of ABS in a 70/30 proportion. The structure cut costs by a third compared with an all-Xenoy part. Also, certain material combinations produce a "laminate effect," which confers higher strength than either material alone, reports Sue Braun, continuous improvement manager at Bemis. Dynatup impact strength of the test part was twice that of an all-Xenoy part.

OPPORTUNITY: Tractor Hoods & Steering Pedestals

GROWTH OUTLOOK: Greater flexibility of part shapes and elimination of painting have allowed plastics to make inroads in hoods and grilles for lawn and garden tractors, says Jim Mason, development scientist at Bayer Corp., Pittsburgh. The steering pedestal - a structural support for the steering column - presents another opportunity for metal-to-plastic conversion, says GE's Boyle. It depends on incorporating enough functionality into the plastic part to make it cost-effective.

MATERIALS USED: Outdoor weatherability and gasoline resistance are essential, as well as good colorability and ruggedness. GE is targeting Xenoy, and Bayer its Makroblend PC/polyester, for tractor hoods. In steering columns, GE has replaced metal parts with glass-filled Valox PBT. In one case, the plastic part incorporated the dash panel.

PROCESSING SKILLS: Computerized injection mold-filling simulation is useful for proper placement of weld lines in these parts, notes Bayer's Makroblend product specialist John Ley. Mason of Bayer suggests using gas-assist molding to help pack out thicker sections and avoid sinks and other visible defects. In addition, coinjection opens up the possibility of combining an unfilled surface resin with good aesthetics and a structural core of glass-filled material, notes Boyle of GE.

OPPORTUNITY: Cordless Tool Housings

GROWTH OUTLOOK: The cordless power-tool market - which includes garden tools - is growing at about 30% per year, far outstripping the overall growth of power tools, according to Chuck Hoar, consumer product manager of AlliedSignal Engineering Plastics, Morris Plains, N.J.

MATERIALS USED: Polycarbonate, PC/ABS, and nylon are major candidates. They need high drop impact strength at weld lines and resistance to solvents. In addition, emphasis on lighter weight is creating a need for thinner walls. That, in turn, demands high-flow materials like AlliedSignal's, Caprun XFI nylon 6, which it is targeting for tool housings.

PROCESSING SKILLS: Familiarity with injection molding engineering materials is the main requirement.