Welding by magnet

Posted By on 2011-06-25

KUKA Systems welds castings and steel components

The history of Magnetarc welding started for KUKA Systems in 1972. Since then, many famous car manufacturers have come to rely on the Magnetarc welding process. The new generation of machines with its open, optimally accessible working space and controller networking capability, provide the ideal preconditions. It is possible to weld different ferromagnetic materials together. A welded joint that lasts a lifetime.

It’s not only car manufacturers that place their trust in Magnetarc welding machines. Machines made by KUKA Systems have also become established in the construction equipment and components industries, because they guarantee one hundred percent quality in manufacturing safety-relevant components such as axles, propshafts and drive shafts. There is probably no other process as fast and reliable for joining components which constantly have to withstand extremely high loads. Particularly when different materials such as castings and steel components are used, a conventional joining process such as arc welding can only be employed with restrictions. The welding of components in KUKA Systems Magnetarc welding machines is completed in a matter of milliseconds, by way of comparison. The shielding gas system enables a process that generates little spatter, ensuring that the process area remains virtually particle-free – thus eliminating the need for postprocessing of components.

The welding process

In the first phase, two workpieces that are to be joined are clamped in the machine. They are moved together so that both workpieces are in contact. As a second step, the shielding gas is activated and the weld current is switched on, igniting the arc. In the third phase, the arc is caused to rotate by a water-cooled magnetic coil, meaning that the abutting surfaces are uniformly heated throughout the entire weld cross-section. The split coil allows time-saving loading and unloading from above, amongst other advantages. The precision clamping equipment with changeover inserts specific for each component allows rapid retooling for different component diameters and geometries. 

In the final phase, the near-molten abutting surfaces are pressed together under forge pressure. The advantage of this welding process is that there is no distortion of the components. Also, it is possible to join components even though they might not be rotationally symmetrical. “The advantage of this welding process is that there is no distortion of the components. Also, it is possible to join components even though they might not be rotationally symmetrical,” explains Andreas Gistl, project manager in Technical Solutions/Welding Processes. “All welds are subjected to tensile and load testing. It is always the base material that gives – never the weld,” Gistl continues. Each KUKA Magnetarc machine works with the maximum precision that is possible in the factory. Each weld is inspected in real time and documented in the PCD.

Subcontracting at KUKA

KUKA Systems not only manufactures the machines, but is also a practical user of Magnetarc technology as a welding subcontractor. “That is a great advantage for us as a manufacturer, because here we can develop and produce jointly with the customer,” explains Walter Weh, departmental manager of Welding Shop Solutions. “Development, process engineering, design and engineering can take place here in-house – and we can even produce the parts. We can respond precisely to customers’ wishes, and get the best result for both the customer and the components,” continues Weh.

Automation made easy

As a rule, company and production-specific factors determine whether a Magnetarc welding machine will be equipped with additional automation components. Basically, all KUKA machines are prepared for integration into an automatic process. Similarly to a modular system, a Magnetarc welding machine can be individually optimized to the particular requirements.

Automation of the Magnetarc welding machine is also possible at a later stage without difficulty. It may be useful to carry out a prior analysis before integrating a new machine into a work process – particularly in the case of robotic machine tending. 3D process simulations provide a realistic representation of the manufacturing cell. This makes it possible to optimize manufacturing processes, robot integration, human-machine interaction and ergonomic factors before the cell is commissioned.

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