New Digital Laser Scanner Speeds Welding of Wind Towers
A new, scanning-spot laser sensor designed to automate
and speed the manufacture of wind towers and other structures containing
metal of different thickness has been launched by Meta Vision Systems.
Designated DLS200, the sensor is produced at the company's factory in
Eynsham, Oxfordshire.
The thickness of the steel plates that form the
base of a wind tower can be 50 mm or more, while the middle section is
fabricated from lighter gauge metal and near the top, the steel is
thinner still. Welding of these various gauges requires different
procedures.
The base is typically prepared with a U joint
profile and welding takes place in several passes. The middle section
requires a V type joint and is welded in one or two passes. Steel at the
top is welded with a simple butt joint preparation. The DLS200 sensor
has a fully programmable scan configuration, which means that a wide
scan can be used for the U and V joints, but a narrow scan with high
resolution can be used for the smaller butt joints.
Another exclusive feature of the DLS sensor is that the
stripe produced by the normal laser scan can be shrunk to a spot. This
is useful for welding cap passes where the edges of the weld preparation
may have melted away. At the touch of a
button, the sensor can project the spot to measure and control the
height of the welding head. At the same time, the machine operator can
use the laser spot as a guide for controlling manually the horizontal
position of the welding head.
DLS200 sensors are already assisting automated
welding of wind towers at test sites and have been well received. Wind
tower manufacturers say that the main benefit of using the sensor to
provide automatic control of the welding process is improved quality.
Defects are reduced, which translates into large savings, especially
considering the time and cost of repairing root weld defects in thicker
material. Bob Beattie, Meta's managing director, said: “We
originally developed the DLS300, launched earlier this year, for
multipass welding of very thick walled components such as nuclear
vessels.
“The new DLS200 sensor has a smaller depth of
field with consequently higher resolution. This makes it ideal for the
combination of large, medium and small weld joints that are common in
wind tower fabrication.
“There is no other sensor on the market that is so
adaptable and it is generating a lot of interest for other applications
as well, such as making piles for offshore structures and pipe elbow
fabrication.”
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