Advanced Welding Processes: Technologies and Process Control

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Advanced welding processes
Off-line storage
Programmer
Operator
operation, but, in practice, the creation of a satisfactory welding program
may take a considerable time. The details of the teaching procedure depend
on the robot, but usually involve teaching the robot motion and operating
instructions followed by editing the program and adding welding parameters.
Two techniques are normally employed:
∑ teach-by-doing, or playback, mode;
∑ point-to-point with interpolation.
Teach-by-doing
Monitor
output
for QA
Network
for CAD/CAM
Input/output interface
RAM ROM
Microprocessor
Input/output interface
Safety
interlocks
11.6 Robot controller functions.
Component
detection
& FMS
coding
Robot
Positioner
Welding
equipment
The teach-by-doing, or playback, mode of programming was one of the
earliest techniques to be used and involves the operator leading the robot
through the weld path and continuously or periodically recording the position
of the welding head. A commercial SCARA system utilizes this approach;
the robot is set in the ‘TEACH’ mode, the program is allocated a number by
means of keys on the controller and the operator then moves the head manually
to the first point to be taught, pressing a button at the rear of the arm to
record the point. Successive points on the weld path are taught in a similar
manner and weld start positions are identified by means of an alternative
button. The program is terminated and stored in memory by means of another
key on the controller. Welding parameters and input/output (i/o) sequences
may then be edited into the program using the key pad and VDU screen on
the controller. The whole procedure may then be run under computer control