CompositesWorld
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NEWS CompositesWorld.com 31 Rotomolded Cores past three decades in several "pivotal" aspects of the rotomolding process, says Alberto Carrara, sales manager for the company's Industrial business unit. "We know how to rotomold a broad selection of polymers — far more than our customers typically need or ask about," he explains. "In fact, in our lab we keep searching for additional polymers that might be suitable for rotomolding but that aren't used in the process today. We work with a local partner who helps us prepare powders by grinding granules [pellets]." Background work on polymers that are atypical of rotomolding has helped guide devel- opment of tooling, machinery and processing enhancements, he notes. "Second, based on our proprietary SMART rotomolding machinery controls and on vacuum-assisted rotomolding, we can maintain tight control of local thick- nesses on plastic parts during the molding cycle," Carrara adds. ird, an identified market need also helped. at, Persico found in the automo- tive segment. e auto industry is an important customer base for Persico's tooling, presses and automated lines used to mold lightweight reinforced ther- moplastic (LWRT) and direct-long fiber ther- moplastic (D-LFT) composites. Rotomolding is an older but smaller segment of the company's customer base, which purchases Persico tools and equipment to produce parts for tractors, commercial trucks and other ground transport segments. Cores presented a means to expand rotomolding's market impact. "We thought there might be a way to introduce our automotive customers to our rotomolding capabilities," recalls Ottorino Ori, sales manager, Persico Industrial. "Automotive suppliers kept contacting us and asking for an affordable core to use in highly complex 3D parts. As we explored further, the market seemed to be waiting for solutions concerning two kinds of thermoplastic cores — soluble and structural." at prompted the team to scout for automotive rotomolding opportunities a year ago, which in turn led to work on composite cores. e team ran experiments, tested a variety of raw materials and announced preliminary results at the SPE ACCE (Novi, MI, US) in September 2016. Based on High-temperature thermoplastic One of the most interesting cores that researchers have roto- molded to date (see inset below) is of polyetheretherketone (PEEK). This stiff, high-temperature, aromatic thermoplastic's melt temperature (343°C) is significantly higher than that of most conventional rotomolding resins. Success is said to be due to the efficiency of the electrical heating systems embedded in the company's SMART tool system (photo on left), which quickly achieves the temperatures required. Cores in common commodity thermoplastics Persico researchers have already rotomolded cores in a variety of thermoplastics, as shown in the photo selection above.