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. Gisma works closely with its customers on all of its developments – most recently on a single-pole, wet-mating 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.
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 sea-water-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 Sinumerik CNCs. The TC77 universal turning machine from the 800 series turns the casings for a high-performance connector measuring up to 3000 mm long. The machine 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. Some work pieces can be manufactured in a single run. In accordance with VDI/DGQ 3441, the machine achieves repeat accuracy of 2 µm in the X- and Z-axes.
The Sinumerik 840D sl CNC plays an equally important role in reducing manufacturing time. 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. The CNC’s integrated and user-friendly ShopTurn software features an animated graphical user interface. 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.
Siemens Industry Inc.
Filed Under: Design World articles, Connectors (electrical) • crimp technologies
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