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The study is part of the company’s ongoing effort to further develop its HD Plastics material database, which is designed to help designers and converters achieve exceptional part quality and increased performance without secondary operations.

Clare Goldsberry

February 21, 2017

2 Min Read
RocTool study demonstrates advantages of mold heating and cooling technologies

RocTool (Le Bourget du Lac, France), a developer of mold heating and cooling technologies, has conducted a study to identify a range of resin materials suitable for RocTool’s molding technologies to produce high-quality parts with high flow and reduced cavity pressure. The study is part of the company’s ongoing effort to further develop its HD Plastics material database, which is designed to help designers and converters achieve exceptional part quality and increased performance without secondary operations, such as painting or decorative films. The database is available to RocTool Process users.

Working in conjunction with injection molding technology company RJG Inc. (Traverse City, MI), RocTool was able to demonstrate the advantages of its technologies, including flow improvement, reduced cavity pressure, high surface replication of the mold and significant gloss improvement. One of the main challenges in the plastics industry is reducing overall part thickness. The flow increase with RocTool’s induction heating delivers design opportunities and expands thin-wall applications.

RocTool developed a specific spiral mold to calculate flow length while pressure sensors were implemented by RJG to assess the capability of RocTool technology to improve mold filling and reduce pressure drop. The spiral mold was developed with variable thicknesses (from 0.5 to 1.5 mm), allowing a complete material characterization. RJG’s process-monitoring eDart system collected data from the sensors, located behind the ejector pin and close to the gate at the end of the fill.

“The partnership provided added value in our ongoing characterization of resins for the HD Plastics material database,” said Mathieu Boulanger, RocTool CEO. The company is evaluating a range of resins from various material suppliers. RocTool is now capable of demonstrating the additional benefits of its technology beyond just a cosmetic advantage. RocTool can provide true comparison data for parts produced with RocTool technologies versus those made via conventional injection molding.

“This information can be very useful and will provide designers with expanded options,” said Boulanger. “We can now bring this unique data directly to the OEM.”

As presented on the graph below, the drop of pressure is radically reduced between the injection machine pressure imposed (1000 bar) and the cavity pressure measured with RJG sensors. The latter shows a reduction of the pressure drop from the injection machine with RocTool technology. It is clearly observed on the pressure sensor at the gate (blue lines); the data between the RocTool and conventional curves is 210 bar. This is emphasized with the second sensor at the end of the fill. That reflects an optimization of the pressure drop using RocTool technology, which allows for a reduction of thickness and sometimes the number of gates.

This first study includes six resins, covering commodity, premium and performance categories.

Roc Tool has now characterized many materials for inclusion in its HD Plastics material database. The company will continue to broaden its material database, evaluating not only targeted commodity resins but also high-performance resins and ultra-polymers. The database will be available on the HD Plastics website by Q3 2017.

About the Author(s)

Clare Goldsberry

Until she retired in September 2021, Clare Goldsberry reported on the plastics industry for more than 30 years. In addition to the 10,000+ articles she has written, by her own estimation, she is the author of several books, including The Business of Injection Molding: How to succeed as a custom molder and Purchasing Injection Molds: A buyers guide. Goldsberry is a member of the Plastics Pioneers Association. She reflected on her long career in "Time to Say Good-Bye."

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