One-piece linkages based on Hytrel thermoplastic polyester in the 35 to 72 Shore D range have been developed to serve in a variety of suspension applications - snowmobiles, all terrain vehicles, machinery, even automobiles.
A conventional linked grommet assembly gets its strength from a rigid metal link, its elasticity from a soft rubber grommet, and its overall stiffness from both materials working together. It seems like a nice combination—until you consider the weight of the metal.
A single-piece, injection-molded, moderate-stiffness elastomer provides a lighter way to achieve a balance between stiffness and strength. The grades used would typically have a flexural modulus of roughly 80,000 psi and tensile strength around 7,000 psi—both far lower than the steel or aluminum used in metal designs. Yet with a cross-sectional area that typically exceeds that of the metal linkage by a factor of three, the plastic design can still provide an effective strength that allows it to compete with the stronger metals. At the same time, the plastic design would typically weigh two to four times less than the metal-based version, thanks to plastics' specific gravity advantage.
Molded plastics also offer opportunities to optimize stiffness through geometry changes. Instead of the mostly fixed geometry of the metal-based design, in which the choice of rubber dictates the spring rate of the grommet, the molded plastic version derives its stiffness characteristics from the geometry of the entire component.
Mark Schuchardt, DuPont Engineering Polymers, Box 7013, Troy, MI 48007-7013; Tel: (800) 441-0575; E-mail: Mark.E.Schuchardt@usa.dupont.com. For more information, Enter 509
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Truchard will be presented the award at the 2014 Golden Mousetrap Awards ceremony during the co-located events Pacific Design & Manufacturing, MD&M West, WestPack, PLASTEC West, Electronics West, ATX West, and AeroCon.
Robots that walk have come a long way from simple barebones walking machines or pairs of legs without an upper body and head. Much of the research these days focuses on making more humanoid robots. But they are not all created equal.
The IEEE Computer Society has named the top 10 trends for 2014. You can expect the convergence of cloud computing and mobile devices, advances in health care data and devices, as well as privacy issues in social media to make the headlines. And 3D printing came out of nowhere to make a big splash.
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This discussion will examine what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.