technology | Hot runners
als, as well as cold runner systems for injection moulding of LSR (liquid silicone rubber). In the FillControl system the position of the melt
front is detected in each cavity, allowing different fill times to be achieved automatically. The system calculates optimised settings of the pin stroke for each cycle, and transmits them to the valve pin controller. Priamus has also introduced a mobile monitoring
Above:The F Ø11 nozzle is a 13mm pitch mini nozzle design from Thermoplay for multi-cavity applications in packaging, medical, cosmetics and electronics
designed to minimise the witness mark on the part (the company claims a gate area of between 0.8-1.2mm2
).
The F Ø11 valve gate nozzle series is available in lengths from 56-106mm as standard, with options for colour change and pin finishes available to optimise the design for specific applications. Another Thermoplay development for the packaging
industry is a new nozzle variant for applications where high injection speeds and pressures are the norm, such as production of thin wall containers. Whitlam says that additional crush seals are used at the face-to-face joint area between the nozzle head and manifold in order to optimise sealing performance at high pressure and to ensure an absence of leakage even when the system has not reached its fully thermally expanded state (such as in the case of an accidental cold start-up). A larger internal bore is incorporated to manage higher through- put rates, with a conformal cooling option available to improve thermal performance. Whitlam says that thermal exchange between the pin and cavity plate has been improved to achieve faster cooling of the gate area and better aesthetics at the injection point. A sister company to Thermoplay within the Barnes
Group, Priamus System Technologies has recently introduced FillControl Control V, an automatic valve gate controller for hot (and cold) runners. The company says that to balance hot runner moulds through the use of cavity temperature sensors, the melt flow in the individual cavities of a multi-cavity mould needs to be determined and then adapted and optimised via adjustment of the corresponding nozzle temperatures. If the pins in the valve gates can be positioned to manage the melt flow then multi-cavity moulds can be balanced without having to change the nozzle tempera- tures of the hot runners, with a resulting improvement in process control. This approach can be used to balance hot runner systems for thermoplastic materi-
40 INJECTION WORLD | November/December 2016
system - FillControl Monitor – that monitors cavity pressures to identify whether parts are completely filled or not. Additional conditions, such as fluctuations in process flow and viscosity, can also be automatically detected and monitored by means of cavity pressure and temperature sensors. By detecting the position of the melt front in the cavity, FillControl Monitor can be used to control switchover to holding pressure. Synventive Molding Solutions, the first hot runner acquisition by Barnes Group back in 2102, has developed its SVG+ system to provide improved performance, efficiency and reliability in sequential valve gate ‘cascade’ moulding of large parts for industries such as automotive (cascade moulding delays the opening of individual valve pins in a multiple-gated part until the flow front has passed to create products without weld lines). “With this new product launch, Synventive is poised
to meet the future demands in the moulding industry,” says Mark Moss, Executive Vice President, Business Development for Barnes Group’s Molding Solutions. “Our modular approach provides efficient options to upgrade hot runner systems with additional technolo- gies to realise the growing quality requirements of plastic parts.” SVG+ systems are equipped with new modular
actuators and Synventive’s SynCool3 technology, which provides indirect cooling of the actuators without the need for separate cooling lines. Claimed benefits
Thin wall parts such as this PS pot by Plastic Legno are typical applications for Thermoplay’s new packaging series high pressure hot runner line
www.injectionworld.com
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