Beyond visual inspection: flatness and roughness for rolling, coating and finishing lines
A product free of visible defects proves the quality of its manufacturing process. Our surface inspection solutions use dual technology — vision and 2D lasers — to detect shape and colour defects, from flatness and depressions down to micrometric grain size. New low-cost, increasingly accurate optical technologies now enable inspections that were unthinkable just a few years ago.
Real-time monitoring
Do you really want to know how flat your strip is? Inline shape detection in real time, feeding back to your mill control.
Inline inspection
Online flatness & planarity
From macroscopic imaging of flatness, wide-range depressions and local depressions down to micrometric grain size.
Inline inspection
Key features
Shape-factor analysis
Multiple flatness indices: I-units, steepness, centre wave, edge wave.
Real-time display
3D shape visualisation and trend monitoring in the operator HMI.
Closed-loop control
Direct integration with mill actuators for automatic flatness correction.
Defect classification
Automatic detection of quarter buckle, centre wave, edge wave.
How flatness measurement works
Advanced laser-based stress measurement technology
Distance measurement
Multiple laser sensors measure distance to the strip surface across the full width at high frequency.
Profile reconstruction
Advanced algorithms reconstruct the full 3D shape profile of the moving strip in real time.
Stress calculation
Convert shape deviation into internal stress distribution (I-units or % elongation).
Actuator feedback
Correction signals to roll bending, shifting or cooling systems for automatic flatness control.
Industry applications
Critical flatness control for demanding applications
Hot rolling mills
Flatness control for hot-rolled strip and plate in steel and aluminium.
Cold rolling mills
Precision flatness measurement for tinplate, automotive and appliance grades.
Aluminium rolling
Flatness control for aluminium sheet, foil and aerospace alloys.
Tension levelling lines
Post-processing flatness verification and shape correction.
Cut-to-length lines
Flatness inspection for precision blanks and sheets.
Slitting lines
Edge wave and crossbow detection for slit coils.
Integrated Automatic Flatness Control (AFC)
From measurement to correction in milliseconds
Measure flatness across full width
Calculate shape-error profile
Compute actuator correction
Send to mill actuators
Verify correction
Resources & documentation
MisPlana flatness measurement system — datasheet
Complete technical specifications including measurement range, accuracy, sensor configurations and installation drawings for all flatness gauge models.
Contact our expertsAFC integration guide
Detailed documentation for integrating LGE flatness measurement with mill actuators including work-roll bending, roll shifting and zoned cooling systems. Includes control algorithms and PLC integration examples.
Request integration guideFlatness control success stories
Read how leading steel mills improved flatness quality by 65% and reduced rejects using LGE flatness measurement with automatic flatness control. Case studies include hot strip mills, cold mills and aluminium rolling lines.
Request case studies