Morgan's ARGA Increases Utilization at
Thrybergh Bar Mill, U.K.
WORCESTER, Mass., September 5, 1996
By using Morgan Construction Company's patented
Automated Roll-Groove Alignment system (ARGA), British Steel's Thrybergh
Bar Mill in Rotherham, U.K., was able to dramatically decrease the
time needed for stand and pass changes.
Morgan estimates that its proprietary ARGA technology
reduces the time needed for a pass change from typically six to
10 minutes, to less than a minute. Stand changes, which typically
take 10 to 15 minutes, can be completed in four to five minutes
after ARGA is installed.
Morgan's Process Control Systems Division developed
ARGA not only to improve mill utilization by reducing downtime,
but also to improve quality by automating processes that until now
have been performed manually, according to Lionel Cartright, director
of rolling mill automation and process engineering at Morgan. Most
rod and bar mills adjust roll-groove alignment using a wrench, only
when the operator physically notices a misalignment. The amount
of adjustment has been determined by the operator's skill and judgment,
not by science.
"Even small misalignments can have a major
impact on the quality and uniformity of the finished product if
they are not corrected, so the ability to automate this process
is a significant advancement," Cartright explained.
One of the components of the ARGA control scheme
is a system which accurately measures off-line redressed rolls and
stores the resultant data. When a stand is first put into service
in the mill, ARGA drives the selected pass to the passline. The
operator then corrects for visible roll buildup offsets, using the
roll position controls on the operator control stations. ARGA then
automatically aligns the desired groove to the passline and any
subsequent groove selected from the roll set being used without
operator intervention.
In addition to controlling groove alignment, ARGA
also automates the screw-down control for roll parting and allows
the operator to control roll positioning when in manual mode, both
on-line and off-line. These features, combined with automatic alignment,
dramatically reduce the time required to change passes.
Ruth Kirkwood-Azmat, ARGA product manager, said
another reason for ARGA's impact on stand and pass changes is that
Morgan's Integrated Control System provides master control over
both ARGA and Morgan's Constant Passline equipment. The two systems
work in tandem for providing quicker, more efficient stand and pass
changes.
"Since ARGA provides an accurate means of
setting up the stands and aligning the grooves, it also becomes
possible to predict much more accurately the required stand speeds.
As a result, some mills may benefit from a reduction in the tension
on the first bar following a change. With the increased control
provided by ARGA, the need for trial bars is greatly reduced."
"Reduction in the number of trial bars alone
can provide significant savings," Cartright said. "When
we factor in the reduction in time needed for stand and pass changes,
together with the savings from reducing the number of trial bars,
ARGA can provide a major increase in the efficiency of most rolling
mills, as it has at Thrybergh. To realize a similar increase in
efficiency by making other improvements could have required an investment
of millions of dollars."
Morgan Construction Company, is a designer and
producer of high-quality rolling mill products and services for
the metal industry worldwide.
Questions or comments can be e-mailed to: sales@morganco.com
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