Wear of paper slitting blades: an examination of worn blades from paper mills

Abstract

Examination of worn rotary slitting blades from several paper mills showed that the predominant wear mechanism is abrasion by a two-body mechanism, in which carbide particles are plucked from the surface of the blades, and a three-body mechanism with hard particles released from the paper as dust. The dimensions of abrasion tracks suggest that the three-body mechanism is more common. Quartz, a minor constituent of paper additives, is identified as a hard material in paper dust. Fatigue cracking is a minor factor in blade wear, causing chipping at blade tips, and is attributed to high cyclical stresses in the early stages of wear. Loss of cut quality during wear is attributed to a transition from shear cutting to tensile cutting which pulls out fibres from the paper web. This tranition is a function of changes in wear angle and wear depth at the blade tip, which in turn are affected by slitter machine settings