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Innovation | hotrunners


Hotrunner technology is extending beyond melt management to melt control, enabling injection moulding of geometries


that would, in some cases at least, not before have been possible. Chris Smith reports


Enabling high end moulding


It may seem a little unnecessary to say this but injection moulding today is becoming an increasingly sophisti- cated business: moulds are becoming more complex; cavitation – at least in areas such as medical and packaging – is increasing; margins are falling; demand to cut cycle time and processing cost is growing. Materials and equipment makers are, of course, working hard to develop products that deliver a competitive edge for their customers. Prime among these innovators, but occasionally overlooked, is the hotrunner industry. Perhaps it takes an outsider to see the potential


value that hotrunners bring to the injection mouding process. Last year US-based precision engineering company Barnes Group paid $335m to acquire US- headquartered hotrunner maker Synventive. Earlier this year it spent a further €275m to buy German mould- maker and hotrunner specialist Männer. Massachussetts-headquartered Synventive is a


leading supplier of hotrunner systems to the global automotive industry, claiming to have more systems in use in this sector than any other supplier. The company has underpinned its market position with the develop- ment of sophisticated fl ow control products for multi-gate part production such as its Dynamic Feed pressure control and more recent eGate and synFlow


www.injectionworld.com


valve pin control systems. Executive vice president Mark Moss describes these


innovations as a signifi cant change in hotrunner technology as they make the melt management system a much more critical element in the production process. “Controlling the heat in the manifold is one thing,” says Moss. “What we have done with our Dynamic Feed is to control the feed to the cavity. We see this adding more capability to the injection moulding process.” Dynamic Feed technology, which the company


introduced a decade ago, allows pressure to be controlled at each gate. The system, which employs pressure transducers in the nozzle, effectively enables each gate to be operated as an independently-regulated injection point and allows production of part geometries that could not be injection moulded conventionally, Moss claims. The more recent eGate and synFlow systems use precise positional and speed control of valve gate pin position to regulate the fl ow of polymer. Introduced last year, eGate uses an electrically-


driven actuator and controller to regulate the position of the pin to within 0.01mm. Together with the ability to set precise velocities and accelerations, this allows mould fi ll to be controlled to a high level of precision and can be used to overcome balance problems and to improve certain cosmetic issues.


November/December 2013 | INJECTION WORLD 49


Main image: Sequential fi ll hotrunner


systems can improve aesthetic


quality in large


area automotive components such as


bumpers and fenders





PHOTO: HRSFLOW


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