Hot runners systems expert Ewikon Heißkanalsysteme offers various drive versions in its hot runner valve gate systems, which allow for easy adaption in diverse application requirements and mould designs.
Frankenberg-based Ewikon in Germany says its multiple valve hot runners range includes standard single drive units with hydraulic or pneumatic valve pin actuation that are either integrated into the clamping plate or attached to the manifold as well as two versions of synchronous plate systems for precise, joint-valve pin actuation. The synchronous plate can be actuated by drive pistons in the clamping plate or by a sliding mechanism, which is driven by a linear servo motor. This technology is used in applications that require absolute synchronous movement of the valve pins or when limited space prohibits the use of single drives for each nozzle, the company says. Application of these models are good for moulds with a very high number of cavities and close cavity spacing or for applications with small shot weights, in which the filling of all cavities with high reproducibility is decisive, Ewikon notes.
Another drive option is the electric drive unit with step-motor technology good for cleanroom applications. This system allows all relevant process parameters such as valve pin speed, closing position and stroke to be set individually and can be finely adjusted during production. Thus, the injection moulder gains full control of the valve pin movements. Also, the control technology with its touch screen control enables sequential gating as well as to having several valve pin positions within one moulding cycle. As such, the drive concept works emission-free and can be used in cleanroom applications for the medical industry without restrictions.
Two types of tip inserts with valve pin guides are available. One features a pre-centring for the valve pin in the gate area and is used when a fully open flow channel layout is required. Application fields here are, for example, the production of optical parts or for rather quick colour changes as well as the processing of reinforced and flame-retardant materials. The other tip insert has a valve pin permanently guided on ridges offering high precision throughout the operation cycle. This version offers maximum wear resistance for valve pin and gate and is thus suitable for high-volume production moulds or applications with very short cycle times, Ewikon says.