The stamping manufacturer COLOP from Wels, Austria prides itself on the quality and precision of its products. When it comes to molding technology, COLOP has placed 100% of its trust in the solutions from WITTMANN BATTENFELD. For the optimal distribution of the tempering medium, COLOP uses the new intelligent WITTMANN FLOWCON with GRUNDFOS VFS sensors inside.
In terms of its manufacturing process, the “Printer Standard” stamp from COLOP is by no means a forgiving product. The “Printer” stamp series is offered in a large number of sizes, so the so-called “image window” associated with the stamp models of that range is also injection molded in multiple sizes. When injection molding the image window, the position of the two lateral surfaces with respect to one another presents a very specific challenge. If the lateral surfaces are too close together, they rub against the stamp housing – which can, in the worst case, cause the stamping function to jam. If the lateral surfaces are too far apart, it becomes difficult to attach the image window to the housing element. In both cases, the stamp cannot be used.
The Grundfos Solution
In order to ensure an optimal distribution of the tempering medium – thereby ensuring the required stability of the parts – COLOP uses two quadruple FLOWCON plus flow regulators from WITTMANN with GRUNDFOS VFS-sensors inside.
One of the two units is used on the nozzle side of the injection molding machine and the other is used on the ejector side.
Each zone of the “FLOWCON plus” uses a VFS-sensor with flow- and temperature measurement. The GRUNDFOS sensor was chosen because it´s very compact, precise and has an unique design where different flow inserts, for different measurement ranges – at same space requirement, can be used for one type of housing.
These flow inserts were installed inside each “FLOWCON plus” circuit and allowed us, Wittmann Kunststoffgeräte GmbH, to design our own housing and give our product a distinctive design.
Furthermore, to give our customer the possibility to choose between different flow measurement sensors within one product.
As a result of the compact design of the mold, the cooling channels are very tightly spaced. That limits the effectiveness of cooling in the individual cores, and therefore requires a highly accurate temperature control within narrow tolerances. For that reason, a WITTMANN temperature controller was installed ahead of the FLOWCON plus. It has special pumps which generate high pressure, resulting in a 40% increase in the flow rates in the individual cooling channels.
Through the parallel distribution to the cooling channels, each individual core of the mold can now be monitored and controlled via the FLOWCON plus. As a result of this method, the outlying cores of the mold, which generate significantly more heat radiation, can also be brought to the optimal core temperature via a reduced flow rate. Stepper motors maintain a constant flow rate, deviating from the preset value by no more than 0.1 l/min, using the GRUNDFOS sensor VFS 1-15 l/min.
The use of the FLOWCON plus as described here – in combination with a suitably modified temperature controller – has made it possible to ensure that the sides of the stamps’ image windows are always in the right position, while the GRUNDFOS sensor inside the “FLOWCON plus” secures the process safety through its high precision of flow and temperature measurements. Ideal conditions have been established which now form the basis for increasing latitude in production.