Gabriele Hopf – Walter Lichtenberger
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View inside the COLOP production facility in Wels, Upper Austria. |
Established by Karl Skopek in 1980, today COLOP Stempelerzeugung Skopek GmbH & Co KG based in Wels, Austria, is one of the most important Austrian companies in the WITTMANN Group. The COLOP Group employs about 450 people and is one of the world’s leading manufacturers of innovative marking devices of all kinds, especially self-inking stamps. COLOP supplies the impressive variety of its products in more than 120 countries. Along with the entire European area, COLOP has established its main markets in the USA, Russia, South America and Southeast Asia.
Beside the now classic address stamps made of plastic with which everyone is familiar, the product range also includes stamps with a high share of steel components for heavy-duty applications, small handy stamps for use “on the road”, flash stamps, and stamps that permit users to set their own text, as well as band stamps and embossing presses. COLOP, whose environmental management system complies with the ISO 14001 standard, has developed a new product line under the name “Green Line”, with models containing 65 to 80% recycled plastics.
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Philipp Pointner, Deputy Head of the Injection Molding Department at COLOP (on the right in the foreground), speaking with Walter Lichtenberger, Head of Temperature Control Technology at WITTMANN. |
The latest innovation from COLOP is the new “Printer Standard” stamp, which is now available in its seventh generation and features both a unique, modern design and a large number of technical advancements. As a highlight, the design of this stamp offers the ability to customize its generously sized ABS plastic image window.
Technology from the WITTMANN Group
COLOP’s commitment to innovation, quality and sustainability is apparent not only in the company’s products, but also in the decision to use the best available production technologies. At the Wels site, COLOP uses only the most modern injection molding technology from the WITTMANN Group.
Most of the 22 injection molding machines installed in Wels are from the fully electric EcoPower model series made by WITTMANN BATTENFELD with clamping forces ranging from 350 to 2,400 kN. Depending on the area of application, the machines are equipped with WITTMANN sprue pickers and/or linear robots and tray changers or with an INSIDER cell. Where an INSIDER solution has been implemented, robots and conveyor belt are integrated into the injection molding system along with other upstream and downstream processing peripherals, thereby resulting in decisive advantages in terms of space requirements, material flow and robot cycle time. Moreover, the machines have been equipped with hot runner and cavity pressure sensor systems.
Philipp Pointner, deputy department head for COLOP’s injection molding operations, appreciates the EcoPower range above all for its high precision and repeatability, both of which are supremely important in stamp production, along with its low energy consumption. This latter feature of the EcoPower model series derives from, among other things, the use of KERS technology (Kinetic Energy Recovery System), which makes it possible to use the braking energy released within the machine.
Sustainable and environmentally sound production of precision products in high volumes – these are decisive factors in our success. “The machines of the EcoPower model range work with high precision and are extremely clean and energy-efficient”, explains Philipp Pointner. And Pointner is also favorably impressed with their compact design and their relatively quiet operation.
Every single injection molding machine is connected to a temperature controller from the TEMPRO plus D Micro series. With reference to those units, Pointner emphasizes above all their low-maintenance operation and high process stability.
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FLOWCON plus and TEMPRO plus D temperature controller. |
WITTMANN BATTENFELD technology for a highly demanding product
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.
FLOWCON and TEMPRO for mold temperature control
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In operation at COLOP: The new FLOWCON plus from WITTMANN improves temperature distribution in the mold. |
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. 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. The two flow regulators are connected to the injection molding machine via an Ethernet interface, thereby implementing the model known as the WITTMANN Group’s WITTMANN 4.0, which enables the integration of an extremely wide range of devices in the control system of the WITTMANN BATTENFELD injection molding machine. WITTMANN 4.0 permits the accurate representation of the user interface of a peripheral device (here the FLOWCON plus) on the control system display of the processing machine.
Moreover, all production data can be stored in the injection molding machine and easily retrieved for future use. 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.
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FLOWCON plus, integrated in the B6P machine control system. |
Through the parallel distribution to the cooling channels, each individual core of the mold can now be monitored and controlled via the FLOWCON. 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.
Prior to the start of production, it is recommended that a reference value be recorded, whereby all of the FLOWCON’s regulator valves are opened in order to determine the maximum flow in the mold. These flow rate values can be stored and compared with those recorded prior to the next production run. This enables the operator to determine whether the mold flow rate values still permit reliable production.
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. Ideal conditions have been established which now form the basis for increasing latitude in production.
Gabriele Hopf is the Marketing Manager at WITTMANN BATTENFELD in Kottingbrunn, Lower Austria.
Walter Lichtenberger is Head of Temperature Control Technology at WITTMANN Kunststoffgeräte GmbH in Vienna.
