Influence of Moisture Content on Cutting Parameters and Fracture Characteristics of Spruce and Oak Wood

Abstract

The objective of this study was to determine the effect of the moisture content on cutting parameters and fracture characteristics of spruce and oak wood. Samples of Norway spruce (Picea abies (L.) H. Karst.) and English oak (Quercus robur L.) were dried to required moisture content and then used for the machinability test on circular sawblade machine. Results indicate that cutting force and feed force increase with increasing moisture content up to the fiber saturation point (FSP). When the moisture content increases above the FSP, the minimum values of cutting and feed force are achieved. Based on performed experiments, the fracture toughness and shear yield strength were derived. Fracture toughness decreases with increasing moisture content. The minimum values of fracture toughness are achieved at the moisture content level above the FSP. Shear yield strength decreases linearly with increasing moisture content: the decrease is up to 17 % compared to samples with moisture content at the FSP. Based on calculated results, the influence of moisture content and wood species on cutting and fracture characteristics was discussed.