Controlling Lifetime of Forming Fabrics

Caliper Reduction Rate

Caliper Reduction Rate

After continued use, the wear side of the fabric becomes abraded and reaches a limit at which the mesh loses its utility. The caliper reduction rate is generally used as a method for expressing the degree of abrasion. The caliper reduction rate is calculated according to the following formula:

T0: caliper before use
T1: remaining caliper

In general, the caliper reduction rate is within the following ranges: (depending on fabric design though.)
For single-layer fabrics: 25-35%
For multi-layer fabrics: 15-30%

When the fabric is abraded and the caliper is reduced to a certain limit, poor drainage, fiber loss, and other papermaking problems might arise. Hence, a curve intrinsic to a specific machine can be obtained by investigating the caliper reduction rate corresponding to the number of days of use (or running distance) and graphing the results. This is generally called the abrasion curve (see figure below), and is useful in forecasting fabric life and in judging abnormalities in use conditions, and other factors.

Since a fabrics’ state of abrasion corresponds to the properties of the machine and the use conditions, investigating the abraded surface is important. Fabric surface should be investigated to determine whether abrasions (e.g. streaks, unbalanced abrasion, and burrs) are normal or abnormal. Positions of abnormal abrasions toward machine direction should be checked and recorded.