Bending Resistance Tester
Bending resistance in paper and board is a complex property depending upon the network characteristics of the sheets as well as the fundamental fibre properties to which it relates. It varies with the type of paper, the fibres used, the making process and the bulk and grammage of finished sheet. The two main criteria which govern stiffness are fibre dimensions and bulk. Rigidity has been found to be linearly proportional to the square root of thickness for a given grammage.
Since the bulk density of a sheet is closely related to the degree of bonding and fibre strength, a change in any of the fundamental fibre properties will affect bending resistance. After configuring test conditions, the test can start immediately. By pressing the “Start”, button the sample is moved automatically. The sample-holder now moves
to the preselected angle-position and the curve with the determined values are indicated on the large touch screen The test will be started automatically as soon the load-cell is touching the sample (pre-load selectable). With the holding function, a holding time can be selected and then a second measurement can be taken. The holding times is very useful for testing label-paper, when the bending-resistance on wet samples should be tested. After the test has been done the sample holder returns to its starting position and the sample can be taken out. By means of the statistic function, the statistic values can be read (maximum, minimum, average, standard, deviation, ratio MC/CD,.. ) on the graphic display.