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Gisma specializes in the production of underwater connectors typically used in offshore energy generation. Siemens Sinumerik-controlled Spinner CNC machine tools contribute significantly to the success of the company.
Special connectors are required to safely and reliably connect electrical and fiber-optic cables deep underwater. With maintenance more difficult, all of the parts must meet the most rigorous technical requirements in terms of reliability and service life. Products from Neumünster, Germany-based Gisma Steckverbinder GmbH are designed to be fail-safe and to withstand maximum pressure loads, while still operating on the basic “push and pull” principle. In addition to shipyards, the offshore oil and gas industry, and the military, Gisma is now receiving an increasing number of orders from offshore energy companies. Gisma works closely with its customers on all of its developments – most recently on a single-pole, wet-mateable power connector for use in offshore underwater turbines, which was designed to handle operating voltages of 12 kV at 400 A and is guaranteed to be fail-safe for 25 years.
Manufacturing repeatability to the nearest micron
To meet the high standards required in underwater technology, manufacturing accuracy to the nearest micron is required, especially for fiber-optic connectors. In addition, the materials must all be corrosion-resistant. The highest levels of functional safety are also required to enable the machining of seawater-resistant bronze and stainless steels, along with more sophisticated materials such as duplex and super-duplex steels, titanium and high-performance plastics. The demands placed on the cutting machines and controllers used in the production of these parts are correspondingly high. For many years, Gisma has relied on Spinner milling and turning centers equipped with Siemens Sinumerik CNCs. “The machines rarely fail, mostly because of the high-quality drive and control technology,” says production manager Michael Königsmann. He is particularly impressed by the TC77 universal turning machine from the 800 series, which will be used, among other purposes, to turn the casings for a new high- performance connector measuring up to 3000 mm long. The TC 77 is built on a rigid Meehanite cast iron base with large tempered steel guide rails, allowing a high cutting capacity, along with good damping and rigidity characteristics. It is equipped with a water-cooled motor spindle, which allows precision turning to within a few hundredths of a millimeter, shortly after switching on. The machine also has a counter spindle and features 12 tool stations with driven tools. “This lets us manufacture some workpieces in a single run, whereas previously it would have taken several,” explains the production manager. In accordance with VDI/DGQ 3441, the machine achieves repeat accuracy of 2 µm in the x- and z-axes.
Consistent CNC strategy since 2000
The sophisticated Sinumerik 840D sl CNC plays an equally important role in reducing manufacturing time. Since the year 2000, Gisma has used only Siemens controllers in its production facility. “By standardizing the controller, we have created an environment where we can deploy our employees flexibly all over the shop floor and operator error has become a thing of the past,” explains Tobias Frerck, Gisma’s managing director. “We have always had great results with Sinumerik controllers and knew we could rely on our competent regional service partners on those rare occasions when something went wrong.” For newly developed products, production manager Königsmann and his staff usually create the CNC programs on external PCs in DIN ISO and then send them over the network to the most suitable machine. If there is a need to manufacture new connectors based upon an existing family of parts, the required CNC programs can usually be adjusted directly on the machine itself. And, just as during initial setup, the Sinumerik 840D sl’s fully integrated and user-friendly ShopTurn software comes into its own here. The animated graphical user interface is completely intuitive, meaning that it can be easily picked up even by temporary staff. The Sinumerik Safety Integrated software package provides additional safety when working in setup mode, allowing operators to monitor the production process with the machine door open. Safety mode allows speeds of up to 2 m/min, and the software ensures that the drives stop quickly after a maximum of 1 to 2 mm, should any problems arise. If anything is unclear when an operator is entering data, he or she can push a single button on the operator console to bring up a help menu. Switching to a text-based DIN interface is just as straightforward, for example, when an experienced programmer feels that he or she can more quickly and easily describe a complex contour using a DIN statement. As always, the main focus remains on achieving the highest possible standards in terms of both the manufacturing and the finished product.
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SIEMENS INDUSTRY, INC.
MACHINE TOOL BUSINESS
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Elk Grove Village, IL 60007
Attention: John Meyer, Manager, Marketing Communication
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