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.
On Memorial Day, Americans remember the sacrifices the US armed forces have made, and continue to make, in service to the country. All of us should also consider the developments in technological capabilities and equipment over the years that contribute to the success of our military operations.
Advanced visualization can depict an entire plant in motion, while also detailing an individual workstation. Individual products can be rendered different for each discipline involved — marketing, engineering, or suppliers.
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.