The HHT (high heat transfer) cooling screw from Rauwendaal Extrusion Engineering Inc. in Auburn, Calif., has recently been modified with a flight configuration designed specifically for PLA foam. The HHT screw uses interruptions, or shifts, in the screw flights to force hot melt from the center of the channel up against the cooled barrel surface (U.S. Pat. Applic. 20050236734, 2005). The screw typically improves cooling capacity 15% to 45% over a traditional cooling screw with slots machined into the flights, according to its inventor, Chris Rauwendaal. He says it also improves axial mixing and foam structure. (530) 269-1082 • www.rauwendaal.com
10556 Combie Rd. #6677 Auburn, CA 95602
Phone (415) 948-6266
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Quadrant will roll out an entire family of such materials within the next two years.