Walk onto most rolling mill floors today, and you’ll find cutting-edge equipment feeding into a measurement process that hasn’t changed much in decades. Manufacturers invest heavily in modern rolling lines for the higher yields and higher quality they promise — yet many are still checking flatness with a Flatness Step Block gauge or Tapered Gauge.

The trouble is that these gauges only tell you about the edges. To measure buckle height in the middle of a sheet, an inspector has to bridge a straight beam across it on pillars of equal height, then reach across to measure the gap between the beam and the peak of the wave by hand — a slow process that still leaves wavelength to be calculated separately before arriving at an I-value, the industry’s standard measure of flatness.

A laser-based alternative

Scantron Industrial Products, based in Taunton, UK, has spent more than four decades building non-contact laser measurement systems. Its Proscan range spans everything from a bench-top non-contact profilometer for research and QA labs to the Proscan Magnum, its largest and most capable system built specifically for the metals industry.

The Magnum measures I-values, wave or buckle height, waves per metre, sheet width, edge waviness, edge camber and cross-bow, all from a single scan, and does it in seconds rather than minutes. A laser triangulation sensor delivers micron-level measurement accuracy and is mounted on an X-Y linear-drive gantry system built on a granite table for thermal, vibration and movement stability.

Where manufacturers typically want around five lines of data captured along the sheet’s length, the Magnum’s custom software can display a user-defined number of lines, with no fixed upper limit.