SMOOTNESS OR ROUGHNESS? June 3, 2020, 12:45 pm

Buyers ask, in the technical specifications of the manufacturer, the indicator is 220 ml/min. Is the smoothness or roughness of the paper sheet?
Let's figure it out. Paper is a natural product consisting of finely compressed wood fibers and additives. To give smoothness, the paper web is driven through the calenders so that the paper sheet can clearly convey the image applied to it when printing.
SMOOTHNESS - the BEKKA method is used to measure the smoothness, which is determined by the amount of air passing between the glass plate and the test paper surface over a period of time in a vacuum chamber for a certain period of time and is measured in SECONDS!
The smoothness index of the paper is from 100 to 300 s.
ROUGHNESS - the indicator is most common in technical specifications. Measured by the BENDTSEN method. Bendtsen roughness is the amount of air flow in ML / MIN passing between the edge of the measuring unit and a sample placed on a glass plate at a constant excess air pressure. Measured in ML / MIN! Paper roughness from 180 to 250 ml/min

 

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