Materials Options Widen
Engineers find more choices for economically solving engineering problems
By Design News Staff -- Design News, January 9, 2005
From microwaveable metal to wood for electronic enclosures, the materials options for engineers continue to expand. Here is a review of some of the latest advances and trends that are changing the face of design when it comes to materials:
Automotive engineers at Dana Corp. looking for more efficient ways to heat metals have turned to a method that traditionally has been a no-no: placing them in microwave ovens.
Normally, metals reflect the microwaves, damaging the microwave source. But Dana engineers found that surrounding the metal with microwave-absorbing plasma prevents the reflection. That makes microwaves a potential source for the heating after all. What could be the result? Researchers say using microwaves to heat metal can improve part quality and save time in metal processing. Learn more at http://rbi.ims.ca/ 4403-541.
In another development that holds promise for expanding materials choices, Inclosia Solutions, a unit of Dow Plastics, introduced the concept of using wood to dress up molded plastic parts on electronics enclosures. Inclosia says it's through its EXO method for adding decorative skins to plastic parts. The company asserts that the process works for other materials, too.
The EXO process consists of robotic or manual placement of a fabric, wood, or metal insert inside a mold cavity. The first shot of plastic is then injected onto the back of the decorative material. A second shot of plastic encapsulates the edge of the first two materials, creating the finished part. The typical bond strengths between the decorative skin material and its substrate exceeds 10 pli, says Tom Tarnowski, a mechanical engineer at Inclosia. To find out more, visit http://rbi.ims. ca/4403-542.
Meanwhile, engineers at Mercury Marine are showing what they can do with plastics. They are making use of polymers from DuPont Engineering Polymers for a range of applications with their new 225-to-275-hp Verado engines. For example, the Verado's new engine enclosure consists of three injection-molded plastic cowls. The topmost cowl-made from a 33-percent glass-filled nylon 66 and measuring 33.5 × 22.9 × 16.4 inches is, the company says, the largest injection-molded cosmetic nylon part in the world. It weighs 11.3 lbs.
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| Mercury Marine used reinforced nylon for the air-intake manifold of the new Verado engine, as well as several other parts of the engine. |
Among the advantages of using injection-molded plastics and splitting the cowl into pieces: reduced cost, fewer defects, and lower weight, engineers say. Some of the weight loss comes from the thermoplastic's specific-gravity advantage over traditional sheet molding compound (SMC). Also, plastic parts have relatively thin nominal wall thicknesses while SMC parts often require bulked-up regions to mold properly Go to http://rbi.ims.ca/4403-543 for more info.
Finally, out of Clemson University comes news of work with embedded piezo-electric materials that give brains to automotive tires and enable them to change shape to respond to varying road conditions. The "smart tires" would have piezo-electric-bases sensors and actuators cured or bounded to the rubber in the tires.
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