Advanced Welding Processes: Technologies and Process Control

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Advanced welding processes
11.3.3 Fixed welding stations
Simple rotary positioners and welding lathes may be used to move relatively
small components under a fixed welding head or even a manually held torch.
Using simple jigging, this type of automation may easily be justified for
relatively small batch sizes. It is particularly suitable for circular weld paths,
but fixed linear slides are also available for straight seams. Even the low-cost
units can include facilities for synchronization of power source switching
and weld crater fill facilities. For larger workpieces, column and boom
positioners, motorized beams, roller beds and turntables are available. [265]
Like the tractor systems these units are most suitable for simple geometric
shapes and the consumable electrode processes, and they are adaptable to a
range of applications limited only by the size and weight of the components
being joined. The major advantage of this type of system is the ability to
carry out welding in the downhand position which enables higher deposition
rates and higher quality to be achieved. These advantages are most significant
on heavier sections and can result in large cost savings in spite of the high
initial cost of the positioning equipment. Typical configurations of these
systems are illustrated in Fig. 11.4.
The most common application area for column and booms, roller beds
and heavy turntables is for longitudinal and circumferential seams in the
fabrication of pressure vessels and power generation plant. Very large units
have also been used for making circumferential joints in submarine hull
sections and power generation system drums.
A
C
11.4 Heavy positioning equipment (not to scale): A, roller bed; B,
tilting turntable; C, column and boom.
B