Hot runner engineering for all-electric injection moulding
The motor is controlled by a modular servo controller. The system designer has the option of integrating it into the moulding machine’s control cabinet or into a separate controller enclosure with a multifunctional control panel. The needles can be moved into any position, and reference runs are not necessary, because the servo drives have absolute encoders.
The sliding mechanism’s precise transmission and the actuator’s exact repetition accuracy make possible a valve gate needle positioning precision of better than 5 µm.
Valve gate technology
The Günther valve gate nozzle series fitted in the mould features optimum thermal separation between the two components of its shaft. This ensures very good insulation in the front area of the shaft and, accordingly, holds the loss of heat between the hot runner nozzle and the mould cavity to an extremely low level.
Another advantage derives from the innovative design of the contouring needle guide, which is made of powder-metallurgical steel.
The optimised valve gate allows noncontact, low-wear operation. During the closing movement, the needle is centred in a conical guide until it moves down precisely into the cylindrical guide. The needle guide can easily be changed if necessary, without the inserts having to be reworked.
The needles are driven and controlled by the servomotor-powered sliding-plate mechanism. The preferred drive for close nest pitches, it enables all needles to be opened and closed precisely.
Special openings in the mould clamping plate allow the valve gate needles’ downstroke depth to be individually adjusted from the outside while the needles are still mounted. In addition to this mechanical option, the controller in the servo drive provides a convenient way to set the downstroke depth automatically; depths can be set in steps of 0.01 mm without any need to take the mould off the machine.
As this technology does not require utility supply bores in the clamping plate, it supports the design of highly compact moulds even for complex parts.
Günther’s high-efficiency complete hot runner solutions offer maximum cost-cutting potential for injection moulding. Unlike selective, local system optimisations, they are equally effective in helping reduce energy costs, ensure reliable process control and eliminate mould making problems.
Günther Heisskanaltechnik GmbH