MATERIALS PREPARATION | TECHNOLOGY
producing preforms made from both virgin and recycled PET (rPET). The company says Genesys- Next enables drying and injection processes to be synchronized, with the dryer acting on the main process variables to help stabilize injection pressure. “Furthermore, the GenesysNext algorithm’s
control is a powerful tool because it has also a capacity of predicting the evolution of the system and so it can act in advance, analysing the trends of the main variables and keep the process stable,” the company says. Material intrinsic viscosity (IV) is a critical parameter in PET preform production, especially when using rPET, since it can vary more from batch to batch. The GenesysNext controller acts on parameters such as dew point, flow rate and temperature of the process air, to keep the injection pressure at its set point value, even if the PET’s IV chang- es. (Piovan has a new system to detect the dew point of the process air, based on the collection of multiple samples of process air, which provides what it says is a more reliable and stable value.) Piovan also highlights the “Pure-Tech” filtering system used on GenesysNext dryers. “The target is no longer only a mechanical filtration of the dust but also a chemical absorption of contaminants,” it says. “The intensive use of recycled material makes the presence of VOCs more and more common; GenesysNext is ready to process any kind of rPET, without compromise in the quality of final product.” GenesysNext also incorporates a range of sensors for performance monitoring and predictive maintenance: these include temperature probes on the desiccant tower and a pressure transducer on the filter. The pressure transducer on the filter enables the controller to estimate residual lifetime of the filtering cartridges. Temperature probes on the desiccant towers make it possible to avoid thermal stress of the molecular sieves, keeping performance steady over time.
Gentle drying of bioplastics Bio-based plastics continue to grow in popularity. But they are not always drop-in solutions. “The required drying parameters, such as drying temperatures, specific dry-air volumes, drying times and dew points differ from familiar data for traditional granulates,” notes Digicolor. It says a project sponsored by the German government has allowed it to systematically develop guidelines for
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the drying of bio-based plastics. “Comprehensive lab tests have been necessary in order to deter- mine, for example, the mechanical and physical properties of the finished parts in relation to the dryness level of the used granulates,” it says. “These interactions as well as the in-depth test
results have contributed to the development of a new dryer series, our Drywell Bioline. These granu- late dryers allow the drying of materials such as bio-based polyamides, PLA or WPC even at low drying temperatures.” Matsui is also eyeing bioplastics,
particularly biodegradable types. It has developed the MJ5-I specifically for such materials, noting that biodegradable plastics such as PLA are known for their strong hygroscopicity, “which makes it crucial that a dehumidifying dryer is used for the drying process.”
“The MJ5-i provides an industry-leading
standard in energy efficiency. Thus, the moisture content can be effectively reduced to the optimal level for moulding, while up to 75% of energy can be saved,” says the company. Matsui adds that a common problem related to
biodegradables is that the material may block during the drying process, causing transportation problems. “This is solved thanks to the drying hopper of the MJ5-I, which guarantees a smooth transportation process,” it says. “Gas problems, which also occur frequently when processing biodegradable plastics, are minimised as well.” The company also highlights the user-friendli-
ness of the unit. “The dust box is accessible from the front side, and the standard installation of a cyclone vacuum type filter renders laborious maintenance unnecessary,” it says. The dryer continuously monitors customer usage and automatically operates in a way that ensures maximum energy and resource efficiency, it adds.
CLICK ON THE LINKS FOR MORE INFORMATION: �
https://plasticsnw.com �
www.aecinternet.com �
www.koch-technik.com �
www.maguire.com �
https://dri-air.com �
www.wittmann-group.com �
www.conairgroup.com �
www.piovan.com �
https://digicolor.de �
https://matsui.net
March 2021 | INJECTION WORLD 43
Left: Upgrades to GasTrac process heaters from Conair include an advanced control system and plain-text operating, diagnostic, and alarm messages
IMAGE: CONAIR
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