gwk cyclic mould heat and cooling vario cs and vario wh

Cyclic temperature control systems are advancing

gwk cyclic mould heat and cooling vario cs and vario wh


Dynamic mould temperature control is a temperature control method that allows temperature variations within the cycle and is also known as “variotherm temperature control”. While this method has been known for almost forty years, it has only undergone a dynamic development in the last few years. This is due to the increasingly exacting quality requirements of consumers (e.g. prevention of visible joint-lines, gloss variations and other surface defects) and the use of plastic materials in new applications. When a temperature control system is selected it is important to mind that it matches exactly with the application and that the economic benefit justifies the technical efforts as well as the energy consumption.

For all applications gwk has got the right temperature control system that can reach fast heating and cooling rates with low energy consumption. Systems of the vario cs series are working with water up to 160°C whereas the vario wh realizes water temperatures up to 200°C. The systems are built in modular design and principally consist of three modules.

The heating process of the mould wall to a high temperature level is affected through a pressurized hot water temperature control with maximum outlet temperatures of up to 200°C. The hot circulating medium is pumped through the close-to-cavity temperature control channels, until a sensor indicates the reaching of the desired temperature of the cavity walls and releases the injection process.


The cooling of the mould wall happens through a temperature controller with highly efficient plate heat exchanger and very low supply temperature. Hereby an intensive and short cooling phase is ensured. The start of the cooling phase is initiated by a machine signal. After the end of the cooling phase, the mould opens and the heating phase for the next cycle begins.

The shift between heating and cooling phase is affected by a close-to-cavity placed valve unit. The  high energy consumption through alternating heating and cooling of the flow medium, is clearly reduced by the close-to-cavity installation of the valve unit. A highly dynamic control system is responsible for the precise switch-over.


Function and installation of the systems vario cs and vario wh are shown at the gwk stand by means of a demonstrator. Furthermore the vario cs is part of two LIVE applications at the exhibition stands of injection moulders:


KraussMaffei produces a panel for a “white goods product” in a MuCell application on a fully electric injection moulding machine. In order to reach the high surface quality the mould temperature control is realized close to the cavity by means of the gwk integrat 4 D mould inserts. Out of the range of cyclic temperature control systems a gwk vario wh with water up to 200°C is used.


Sumitomo Demag produces a multi-touch display in a compact production cell that combines IMD with IML technology. The cyclic cavity temperature control gwk vario wh is responsible for the required surface quality and the avoidance of visible joint-lines.

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