Regrind (flake/chips) from cross-linked, rotationally molded parts can be successfully added to injection molding resins. That's the word according to a recent study sponsored by the Association of Rotational Molders (ARM, Oak Brook, IL). Researchers looked at combinations of flake or powder in two typical polyethylene resins, HDPE and LMDPE. Regrind content varied from 15 to 75%. Some of the findings: Although the amount of shrinkage depended on the base polyethylene, shrinkage decreased as recycle content increased. In HDPE, there was a decrease in tensile modulus, but an increase in flex modulus of almost one-third. LMDPE showed a significant increase in both the tensile and flexural moduli. Also, a 50% regrind flake in HDPE resulted in 10-to-30 fold Izod improvement. In LMDPE, no breaks occurred. Elongation at yield did not change significantly with regrind in HDPE, but decreased sharply with at least 15% regrind in LMDPE. For most applications, representatives of ARM say, it should now be possible to select the important properties from the study and determine the appropriate blend with which to begin trials for potential products. Users are cautioned to note that this study was conducted using post-industrial scrap, i.e. the regrind came from molded parts not shipped to the marketplace. The report costs $25. Call: (630) 571-0611, www.rotomolding.org on the Internet.
During a teardown of the iPad Air and Microsoft Surface Pro 3 at the Medical Design & Manufacturing Show in Schaumburg, Ill., an engineer showed this "inflammatory" video about the dangers of maliciously mishandling lithium-ion batteries.
Science fiction author Isaac Asimov may have the best rules for effective brainstorming and creativity. His never-before-published essay, "On Creativity," recently made it to the Web pages of MIT Technology Review.
Much has been made over the potentially dangerous flammability of lithium-ion batteries after major companies like Boeing, Sony, and Tesla have grappled with well-publicized battery fires. Researchers at Stanford University may have come up with a solution to this problem with a smart sensor for lithium-ion batteries that provides a warning if the battery is about to overheat or catch fire.
In this new Design News feature, "How it Works," we’re starting off by examining the inner workings of the electronic cigarette. While e-cigarettes seemed like a gimmick just two or three years ago, they’re catching fire -- so to speak. Sales topped $1 billion last year and are set to hit $10 billion by 2017. Cigarette companies are fighting back by buying up e-cigarette manufacturers.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.