The Effect of Machine Draw Tensions on Sheet Properties

A machine run was made on 75% softwood, 25% hardwood bleached kraft. All variables were kept constant except for the draw between dryer sections. This was varied between -0.2 fpm and 2.0 fpm at approximately 90 fpm wire. speed. Samples were taken at eighteen points between -0.2 fpm and 2.0 fpm and tested for moisture content, basis weight, tensile, elongation and tensile energy absorption. Moisture content was found to vary from 59.5% to 63.2% dryness while the basis weight varied from 39.2 to 41.1 lb. (25x38-500) ream. The basis weight showed no effect on percent dryness. Both the percent elongation and TEA values were shown to decrease with increased draw in both machine and cross machine direction. With an increased draw the machine direction tensile factor was shown to increase 12% followed by a 6% decrease. In this experiment percent elongation was shown to have more effect on TEA than did the tensile