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HHASCO Universal needle valve Z10710/..., unlimited flexibility
Conventional single-shot needle valve solutions that are commonly used in the hot runner zone impose a variety of restrictions on the user and frequently lead to problems in practical application. Splitting of the melt produces weld lines on flat surfaces, the choice of nozzle lengths and diameters are limited, and it's not possible to directly transfer the results gained from single-cavity development moulds to their multi-cavity counterparts because the nozzle type varies, and because the size of the conventional single shot needle valve systems result in a large overall installation height demanding larger mould configurations.
With its new Z10710/... Universal needle valve unit, HASCO has created an amazingly simple solution addressing these problems. The basic concept for the needle valve system is focused on a universal and modular design.
The needle drive unit is available in two standard sizes and can be combined with all HASCO Techni Shot and Valve Shot nozzles. This offers the user a very wide choice of nozzle type and size, allowing runner diameters and nozzle lengths (up to 300mm) to be optimised, as well as flexibility in the design of the needle guide and gating solutions. Technical applications with varying article weights and fillers are just as easy to realise for both packaging and medical applications. The system is extremely compact and can be easily integrated into small moulds with reduced build height.
A major advantage of the Z10710/... is that the unit can be used either as a single nozzle centrally mounted in the middle of the mould - or as a drive unit mounted between the manifold and nozzle. This means that the findings obtained in pre-production and prototype moulds with a specific type of nozzle configuration can be transferred without risk into a multi-cavity production mould. It's even possible to carry over the hot runner components, reducing the cost of gaining vital development knowledge before committing to the production mould.
When the Z10710/... is positioned between the manifold and the nozzle head, the unit has the added advantage that axial thermal expansion of the manifold block has no influence whatsoever on the valve pin position, thus preventing any needle deflection. The optimum L/D ratio through the short needle length extends the service life of the needle and gate aperture.
Priority has also been given to flexibility when it comes to the choice of drive unit. The Z10710/... can be activated either pneumatically through special cylinders mounted outside the mould, whereby the needle position can be finely adjusted at the cylinder, or hydraulically through ultra-compact hydraulic drive solutions integrated inside the mould.
The valve pin stroke can be varied with both drive solutions in a range of 2 to 17mm. This means that the Z10710/... can be geared to suit to the application and the respective nozzle type.
The rotational position of the needle valve is accurately fixed, allowing cavity form contours to be included on the pin.
From a rheological point of view, the new HASCO Universal needle valve Z10710/... also has a lot to offer. There is no splitting of the melt which means that weld lines that are a particular nuisance on flat visible parts can be completely avoided in combination with the suitable HASCO nozzle type. Generously designed melt channels ensure the pressure losses in the system are kept to a minimum. Guiding of the melt is soft without any dead spots, thus preventing shear and material degradation.
When designing the Z10710/..., particular importance was attached to a homogeneous, symmetrical temperature profile. The Z10710/... can also be used for glass fibre-reinforced plastics, which are particularly demanding from the processing point of view.
A particularly interesting field of application with the Z10710/... is in stack and tandem moulds. With the needle valve drive system positioned between the nozzle and manifold, back-to-back arrangements with individual needle drives are easily accommodated. The overall height of the centre of the stack (gate-to-gate distance) can be reduced to 250mm.
Priority has also been placed on ease of maintenance with the Z10710/... The heating unit, temperature sensors and needle guide element are very simple to replace if necessary.
Further informations:
HASCO Universal needle valve Z10710/... PDF
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