Effect of Chipper Knife Wear and Operating Parameters on the Dimensional Fractionation of Wood Chips in an Industrial Chemical Pulp Production Line – Case Study

Abstract

Dimensional uniformity of wood chips is essential for stable delignification, and knife wear in a disc chipper is the primary factor that deteriorates chip quality. In this study, changes in particle size distribution (PSD) of pine wood chips were examined at three points along an industrial chip‑processing line, assessing the effects of knife sharpness, knife–anvil clearance, and transport and screening operations. Sharp knives combined with a narrow knife–anvil gap produced the lowest proportions of oversized and fine fractions, whereas progressive dulling significantly increased chip susceptibility to cracking during subsequent handling. The results indicated a need for more frequent knife maintenance and proper adjustment of the knife–anvil clearance to ensure stable chip quality under industrial operating conditions.