EMG: Online roughness and waviness measurement in hot-dip coating lines

Conventional surface roughness measurements are based on mechanical stylus devices that require the production line to be stopped or offline sample testing. These methods are not only time consuming, but also lack the statistical power required for modern manufacturing standards. EMG Sorm revolutionizes this process by providing a non-contact online measurement system that operates at production speeds of up to 350 m/min. The system utilizes a confocal chromatic measurement principle where different wavelengths of light are focused at different distances, allowing precise measurement of the strip's micro-profile. Important roughness parameters such as Ra (arithmetic mean roughness), RPc (peak count) and Wsa (waviness) are calculated from this profile data. By integrating this solution into a production line with a traversing unit, EMG Sorm allows continuous monitoring of roughness and waviness over the entire width and length of the strip, thus ensuring a comprehensive evaluation of surface quality. In hot-dip galvanizing lines, where the metal strips are coated with zinc or alloys, the control of surface roughness is crucial both for the adhesion of the coating layer and for the visual appearance of the end product. The same applies to continuous annealing lines. EMG Sorm excels in these environments by providing online data that allows operators to detect and correct deviations immediately.

The system's ability to visualize and record roughness and waviness parameters online enables immediate corrective action to optimize rolling and skin pass processes. This capability not only improves product quality, but also reduces costs by extending the life of work rolls and minimizing scrap in subsequent quality assessment procedures. The implementation of EMG Sorm offers numerous benefits resulting in a short return on investment (ROI). The system's ability to instantly detect roughness and waviness deviations ensures that potential problems are addressed before they affect the final product, resulting in a significant reduction in customer complaints. In addition, EMG Sorm can contribute to a more efficient and cost-effective production process through the ability to optimize skin pass mill control and the associated guarantee of homogeneous surface quality. EMG Sorm represents a significant technological advance for anyone looking to improve surface control in their production line. The system's installation flexibility, small footprint and ease of integration make it an ideal choice for modern production lines for flat metal products.