Automatic surface inspection system for tin mill black plate (TMBP)

This paper introduces an automatic surface inspection system applying a charge coupled device (CCD) line scan camera, which was installed at a continuous annealing line at JFE Steel. The line is the final product manufacturing line for tin mill black plate (TMBP) and has the world's highest operating speed. The resolution of the camera during surface inspections is 0.17 mm (cross-web) × 1.25 mm (down-web) at a strip speed of 1 400 m/min, and a defect detection ratio of 95.5% has been achieved. Since installation of this system, complaints related to strip surface quality have decreased to 1/20 of the former level An adjustment method using artificial defects and a daily check method using the weld point, which is the joint between product coils, were also established, establishing a system for maintaining the accuracy of the inspection system.