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Up to 100% flow length improvement (cavity thickness of 1.5 mm) with PEI. |
A top supplier, RocTool commits itself to a constant study of various polymer materials, aimed at identifying those ideally fit for the use of mold cooling and heating technologies in quality part production. This study is encompassed by the ongoing development of the HD Plastics™ material database, conceived by RocTool with designers and converters in mind. The database, accessible by RocTool process users, is aimed at achieving outstanding part quality and downstream performance (coating, application of decorative films, etc.)
RocTool collaborated with RJG Inc., based in Traverse City (USA), a worldwide leader in injection molding technology, resources, and training, in order to prove the benefits of RocTool technologies. These include flow, mold surface replication and gloss improvements, as well as reduced cavity pressure. Modern plastics processing industry works constantly on minimizing part thickness. Flow increase provided by induction heating system developed by RocTool pushes current boundaries in thin-wall applications by offering new design opportunities.
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Injection and cavity pressures in RocTool technology (solid line) vs. traditional injection molding (dotted line) as measured with RJG equipment – an example from PC trials (thickness of 1.5 mm). |
The study used a special spiral mold of variable thickness (0.5 to 1.5 mm) designed by RocTool for flow length calculation. RJG Inc. deployed pressure sensors powered by eDART System™ for process monitoring. The sensors, located behind the ejector pin, close to the gate and at fill end, helped assessing pressure drop reduction and mold filling improvement with RocTool technology. This complex setup allowed for complete material characterization.
Mathieu Boulanger, RocTool CEO, commented on the project: “This partnership provided added value in our ongoing characterization of resins for the HD Plastics™ material database. Gathered information can be very useful and will provide designers with expanded options. We can now bring this unique data directly to the OEM.”
RocTool’s evaluation of resins from various suppliers allowed the company to prove the additional benefits of its proprietary technology. The company can now provide factual comparison data for items manufactured with RocTool technologies versus those produced by traditional injection molding.
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Flow length increase at constant injection pressure and cavity thickness (1000 bar / 1.5 mm). |
As evidences the graph attached, the drop between the imposed IMM pressure (1000 bar) and cavity pressure measured with RJG sensors is drastically reduced with RocTool technology. Such a pressure drop optimization allows for part thickness reduction and for possible reduction in number of gates.
Injection and cavity pressures in RocTool technology (solid line) vs. traditional injection molding (dotted line) as measured with RJG equipment – an example from PC trials (thickness of 1.5 mm)
This spearhead study included six polymers covering commodity, performance and premium applications. The study revealed that RocTool molding technologies could increase flow length up to doubling it, depending on the material (see graph).
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Improvement of TPO appearance. |
Moreover, thanks to RocTool technology, mold surface replication level went up to 97.2 percent, providing product developers with high gloss, premium look, and matching texture of finished parts compared to conventional injection molding. Gloss improvement is especially impressive for fiber-reinforced polymers.
As the picture shows, TPO gloss amounted to 41 GU only in a traditional process versus 79 GU with RocTool technology. Particularly impressive results were observed with filled resins, e.g. 10% glass-filled PC-SAN (a 130% improvement).
RocTool intends to broad its HD Plastics™ material database further: not only commodity polymers but also ultra-polymers and high-performance resins will be assessed.
Full database is said to be accessible via the HD Plastics™ web portal by the third quarter of 2017.
