Cross transports with photocells detect the profiles and position them at the correct distance apart
for the shotblasting of multiple pieces in one pass.
Immediately after processing, transfer mechanisms
move the beams to the next operation. Encoders
and sensors in the roller conveyor register the exact
position of the batch. When the sensor on the infeed
control is passed, a new batch of beams is transported onto the infeed conveyor. The new batch
holds position until the first bundle passes the outfeed sensor. The height of the beams is monitored
to ensure the dimensions comply with the data in
the software, and the height of the brush and blowoff unit is adjusted to remove any blast media from
the web area before the beam moves to the next
Cross transports between two machines function as a buffer to equalize differences in production speed. Beams on the cross transports are automatically repositioned to create enough space for
the next bundle of beams. The software knows the
beam positions and dimensions to ensure all operations connect seamlessly to each other—and all of
this is followed in real time by the production office.
Mechanical drag-dogs move beams rapidly over
the cross transports to minimize transfer time between machines. Before the beam crosses the infeed roller conveyor, the feed slows as it approaches
the datum line to prevent damage.
A servo-driven feeder truck moves the beam, and
at the same moment, the roller conveyor moves the
beam toward the servo-driven feeder truck. This
Automated welding has now reached the beam line. Before striking an arc, the welding gun touches off the wire
tip to ensure accurate positioning.
also reduces the transfer time. The beam is then
processed while the next beam is transferred close
to the infeed roller conveyor.
Short pieces (less than 47 in. long, for example)
are removed and pushed sideways into a bin by a
short product removal system. Leading and trailing edge trim cuts are removed and deposited in
the scrap bin with no manual intervention. Finally,
the long pieces are transported to the outfeed cross
transports and are removed.
Enter Welding Automation
The next step, now a reality but still in the early stages of adoption, is adding robotics to the structural
fabrication shop. Robotic welding and thermal cutting are not new to structural fabricators, but automated welding is—that is, welding with no manual
intervention whatsoever. This includes program development and moving material in and out of rotating fixtures.
Two technology advancements make fully automated robotic welding possible. First, weld programming in these systems now can be automated.
Traditionally, robotic welding systems still require
programming, so a structural fabricator usually
takes a welder and makes him a programmer. But
the goal is to reduce overhead and increase efficiency, not increase the labor burden.
Second, robots use sensors and probes (including
the use of the welding wire tip as a touch probe) to
measure and adapt to workpiece variation. For instance, intelligent systems now can probe toed-in or
-out flanges, off-center webs, and whether material
is within mill tolerances.
Intelligent welding systems can import data from
CAD, if the welding information is in the model. If it
is not, a database can recommend the welding information to add to the model; a programmer then
can take this recommendation or add in the welding
At the end of the beam line, beams are automatically loaded into the welding system. From here the
detail (that is, the part to be welded onto the beam)
The industry has moved
from manual fabrication to
The leap has been a large
one, with massive reductions
in labor and huge increases
in output, and technology
will continue to drive
the industry forward.