Application of traceable sample area measurement in the calibration of online dry grammage measurement used in board production

A method is described for the simultaneous calibration of online grammage and moisture measurement by applying machine reel sampling and traceable sample area measurement. The area measurement is based on a flatbed scanner and image analysis. It is demonstrated that a relative uncertainty of 0.5% can be achieved in dry grammage calibration at the 95% confidence level. The determination of grammage and moisture were performed by applying the EN ISO 536 and the EN ISO 287 standards, respectively. The described technique can also be applied with the calibrations performed for the paper industry.

► A method for simultaneous calibration of online grammage and moisture measurement is described.
► The method is based on machine reel sampling and traceable area measurement with a flatbed scanner.
► The best performance of the method was evaluated at board production lines.
► The uncertainty of the dry grammage calibration can be decreased with the method.