Page 53 - IIW White Paper

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Through Optimum Use and Innovation of Welding and Joining Technologies
Improving Global Quality of Life
Use of manufacturing simulation for automated process planning and real-time system monitoring
Autonomous robot transport vehicle (RTV) navigation for high accuracy positioning of a robot arm
in an industrial manufacturing environment.
Design and build of an industrially rugged RTV with the accuracy and stability required for welding
tasks.
Use of specially developed welding consumables, welding procedures and sensor systems designed
to allow “all positional” robotic welding with a degree of control and dexterity unmatched by
current systems.
Figure 5.2
illustrates the developed system.
The system can be equipped with several sensors:
Torch collision unit, contact sensor for searching start and endpoints for the welds.
Laser sensor system for joint tracking and through-the-arc system for joint tracking as well as a
camera system for monitoring the complete station.
The application also includes a CAD-based system for simulation of the whole process and off-line
programming. This solution with the welding system moving to and around the large work piece can
become a new concept instead of manipulating the work piece to get the best welding position for the
robot. Simulation software are becoming powerful tools. ABB is marketing a programme named VirtualArc®
for simulation of the arc welding process. Robot Studio is another simulation package for movement of
the robot offered by ABB. The two programmes can easily be justified due to the high savings that can be
achieved.
5.1.2
Renaissance for EB welding
Thanks to the great interest in laser beam welding and the increased number of applications, the electron
beam (EB) welding process has been rediscovered and considered to be complementary to laser welding.
Earlier the EB was judged to have many advantages when considered alongside more conventional multi-
pass arc welding processes for fabrication of heavy section structures and components.
Figure 5.2
Robot with all its equipment
mounted on a RTV welding a large structure
(
Reproduced courtesy: TWI Ltd)
Figure 5.3
Comparison of single pass EB
weld profile with multi pass submerged arc
welded joint in 100 mm thickness C-Mn steel
(
Reproduced courtesy: B. Pekkari)