Node welding robot

Node welding robot

Keywords Motoman,Robots, Steel, Welding

A Motoman robotic welding cell, the third to be installed by the Karlskrona shipyard (Sweden), is currently being used in the fabrication of steel nodes required in the construction of the Oresund bridge linking Malmo (Sweden with Copenhagen(Denmark).

The cell, which has cut manual welding times for the nodes by up to 50 per cent, comprises an XYZ gantry mounted Motoman SK6 welding robot interfaced with an especially developed 20 tonne capacity manipulator. Programming is via a state-of-the-art Yasnac MRC 32-bit microprocessor control.

 The MOTOMAN XYZ gantry robot welding system used in the welding of steel nodes for the Oresund Bridge linking Sweden with Denmark

To optimise up-time, use is also made of Motoman's ROTSY offline software which enables programming and production to run hand in hand.

Each node welded is approximately seven meters long, weighs up to 20 tonne when completed, and requires three passes through the robot cell.

According to Karlskrona's production manager, Michael Tranberg, the use of robotic welding was dictated by a number of factors:

"We have 108 nodes to produce. These are fabricated from steel sheet varying in thickness from 12 to 30mm, depending on final placement. In the welding process, we will deposit some 330 tonne of wire.

"If we relied on manual welding it would take far too long. A skilled worker, for instance, can melt about 2.5kg wire/hr. With the Moroman SK6, using rapid arc, we can deposit 8-10kg wire/hr and improve weld consistency.

"Minimising hazards and making the job interesting is also important as we have high expectations with regard to quality.

"Operators, therefore, do their own programming. The MRC is extremely user friendly but to simplify further and provide flexibility, we had a tailor made software system prepared. This is proving ideal."

Construction of the Oresund Bridge will take some 16,000 tonne of steel. The highest part is 1000m long and consists of 54, 20m sections each of which weighs around 250 tonne. Each of the pylons holding the bridge is 240m high and the free height underneath is 60m.

For further information contact Robert Lewis, Sales and Projects Manager, Motoman Robotics (UK) Ltd. Tel: +44 (0) 1295 272755.