New Database Documents Advantages Of Rapid Heat/Cool Molding

Enhanced flow and gloss are measured with several different resins.

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As noted in our February report on tooling news at the K 2016 show in Dusseldorf, RocTool of Charlotte, N.C., has been conducting experiments and compiling a database of how different resins respond to rapid heat/cool injection molding using RocTool’s induction mold heating and high-capacity water-cooling systems. RocTool has branded this technology HD Plastics (HD = high-definition). Now, the firm has released some details on its growing HD Plastics Material Database, comparing results of rapid heat/
cool molding with its technology and conventional injection molding with continuous water cooling of the mold. RocTool developed an instrumented spiral mold to calculate flow length that has variable thickness from 0.5 to 1.5 mm. RocTool also collaborated with RJG Inc., Traverse City, Mich., to monitor cavity pressures in the mold with RJG’s sensors and eDart data-collection system.

The first study analyzed six common amorphous and crystalline resins (see graph) in commodity and engineering categories. Results showed flow length increased from about 40% to over 100% with RocTool technology. Experiments with PC showed much lower pressure drop between start and end of fill with RocTool’s approach. Tests with TPO in molding a rectangular part with a large, flat surface showed a gloss reading of 79 with RocTool technology vs. 41 for conventional molding. Likewise, 10% glass-filled PC/SAN alloy showed a 130% gloss improvement.

RocTool continues to expand its material database and plans to unveil it on its website by the third quarter of this year.

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