"Delta-Eye" Surface Inspection System
Installed at Continuous Annealing Line
NKK has completed installation of its acclaimed "Delta-Eye"
steel strip surface inspection and marking system at the No. 4 continuous
annealing line (CAL) of Fukuyama Works. The system uses three channels
of polarized light to accurately detect and automatically mark very
fine flaws on the surface of steel strip before coils are shipped to
automobile manufacturers. This enables shipments of larger coils to
be delivered to automakers, helping improve coil handling during the
shearing process. It also reduces coil inspection workload after pressing
by automakers, significantly increasing productivity.
NKK introduced its first Delta-Eye system to the Fukuyama
Works No. 2 hot-dip continuous galvanizing line (CGL) in 1999 in an
effort to boost quality assurance for galvanized steel sheets used to
produce automotive outer panels. Given the favorable acceptance it received
from customers who valued the precisely inspected and flaw-marked coils,
the company later added a second system to the No. 3 CGL and has now
installed a third at the No. 4 CAL to handle cold rolled steel sheets.
Tailoring the system to meet the needs of the CAL, NKK
made several improvements on the previous models, including incorporation
of newly developed ultra high-speed sensors to identify reflected light,
signal processors and real-time marking equipment, in order to cope
with the extremely fast running speed of strip in the CAL. With a maximum
processing speed of 600m/min., the CAL treats strip more than three
times faster than the CGL. In addition to high-speed inspection devices,
improvement was also made to deal with the highly reflective optical
surface properties peculiar to cold rolled steel strip treated at the
CAL.
NKK is now able to apply its highly reliable online surface
inspection and marking system to both galvanized and CAL-processed cold
rolled steel sheets and plans to increase production of marked coils
of highest grades for automotive customers.
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