Advanced Welding Processes: Technologies and Process Control

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Advanced welding processes
computer (either a mainframe or a personal computer depending on the
system).
∑ The workpiece and joint description may be loaded into the program and
the welding operation may be simulated using the selected robot.
∑ The completed simulation may be translated into the real robot’s control
language and transmitted to the system via a data link.
Typical simulation and off-line programming packages offer fast and realistic
solid model simulations of the application enabling the proposed installation
to be fully evaluated and optimized without incurring production downtime.
CAD files of workpieces and fixtures may be read into the package which is
equipped with a large library of robot definitions. The performance of the
robot cell may be tested and potential problems (e.g. collisions and access
limitations) are readily identified and displayed on the monitor. The system
also offers the facility to generate CAD drawings of the final work cell and
transfer the simulated program to the control system using the native language
of the appropriate robot.
An interesting example of the off-line programming approach is its
application to shipbuilding. A typical system consists of a portal frame, from
which an articulated arm robot is suspended; the frame is lowered into the
work area and an initial joint-locating program checks the orientation of the
system and corrects the datum settings. Off-line programming is used to
prepare the program and this is downloaded to the controller so that, once
the unit has established its exact position, it may carry out the prescribed
welds.
A similar system has been used in the Odense shipyard in Denmark with
a Hirobo NC programmable robot. The programs created on a personal
computer are, in this case, transferred to the robot controller via a plug in
bubble memory and the robot is only out of production for 30 s. [287] The
system has also been linked to a simulation package and the shipyard’s CAD
facility to enable more efficient off-line programming to be accomplished in
the future.
11.9.2 Integrated automation systems
Many of the automated welding systems of the type described above have
been developed into integrated systems, in which the welding cell is selfcontained,
but linked to other manufacturing processes by a data communication
network. Several manufacturers now offer robotic welding ‘cells’ configured
for a particular range of applications and supplied complete with all the
necessary services including safety screens and fume extraction.
Alternatively, dedicated or modular systems with computer control may
be used to construct the basic cell. The integrated welding system approach
may also be used with computer-controlled modular automation or dedicated