Forty-five percent of serious plastics product failures result from inappropriate materials selection, said Melissa Kurtz, senior materials scientist at Stork Technimet Inc. in a lively discussion on failure analysis at the annual technical conference of the Society of Plastics Engineers in Milwaukee, WI. “This is especially true in applications involving chemical attack and environmental stress cracking,” she said. In one example she cited a phthalic-based plasticizer used in a rubber seal caused environmental stress cracking of polyetherimide in a medical device. In a panel discussion, a General Motors engineer asked for tips on how to determine if excessive use of captive regrind could be causing a part failure. Experts suggested testing melt index of material before molding to determine if the molecular weight was out of range.
At IMTS last week, Stratasys introduced two new multi-materials PolyJet 3D printers, plus a new UV-resistant material for its FDM production 3D printers. They can be used in making jigs and fixtures, as well as prototypes and small runs of production parts.
Plastic bags can become useful as either raw materials for plastics or feedstock for fuel. It's when they're not recycled that they become a major problem. That's what California's bag ban will prevent.
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