provided by: Design NewsApplications of molded plastics continue to extend due to enhanced properties and moldability. New glass microspheres are 40 percent stronger, even though only half the size of previous versions of the product. The glass bubbles can be used, where suitable, to replace glass fiber or fillers and at the same time improve the rheology of the plastic compound. Also worth noting is an important new aircraft application for a high-temperature plastic that replaces aluminum, as the plastics assault on metals continues in the battle to lightweight aircraft.
- Peek PerformanceDoug Smock
Weight played a major factor replacing aluminum with a polyetheretherketone (PEEK) for the hubcaps enclosing a new tire pressure monitoring system for the landing gear of the Boeing 777. "By specifying Victrex PEEK polymer, each hubcap now weighs less than 7 kg (1.5 lb)," says Jeff Tonn, design engineer at Crane Aerospace & Electronics of Lynnwood, WA. "With 14 wheels per plane, the weight reduction is considerable." The tire monitoring system on the Boeing 777 is designed to assure proper tire air pressure for take-off and landing. The hubcaps include a conduit which allows a rim-mounted pressure sensor to communicate with an onboard system providing real-time data to the cockpit. http://rbi.ims.ca/5697-588
- Tiny Glass BubblesDoug Smock
Tiny glass microspheres act like ball bearings, improving the flowability of plastic compounds and allowing more complex parts to be produced. The new 3M Performance Additive iM30K is the first hollow glass microsphere in 3M's line of glass bubbles that can withstand higher pressures involved in thermoplastic compounding, injection molding and extrusion processes in the plastics industry. The new microsphere of borosilicate glass is water insoluble, chemically stable and low on alkalis. It is 40 percent stronger than 3M's previous leading high-strength glass microspheres while being only half their size at a diameter of just 17 ?m (D50). The isostatic crush strength of the new microsphere is 2,000 bar (200 MPa). http://rbi.ims.ca/5697-587
- Overmolded Cowl VentsDoug Smock
A thermoplastic elastomer is used for the cowl vent seals on two series of Peugeot automobiles because of its unusual combination of rubber-like mechanical properties and weathering resistance. Situated between the windshield and the engine compartment and spanning the width of the vehicle, the cowl vent permits fresh air to pass from the outside to the interior. For the Peugeot 207 and 307 series cars, sealing lips of Tekron TPE that are up to 1.5m (nearly 5 ft) long are overmolded onto cowl vent substrates of glass-reinforced polypropylene (PP). The over-molding is part of a single molding cycle for a three-component part that includes the structural PP substrate, the Tekron sealing lip and a molded-in view port which enables the chassis number of the vehicle to be visible. http://rbi.ims.ca/5697-589
author: By Doug Smock, Contributing Editor, Materials and Fastening
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