Abstract

In Eastern Canada, black spruce (Picea mariana (Mill.) B.S.P.) has recently been introduced in the finger-jointing industry. However, little information is available on some of the key manufacturing parameters that influence the finger-jointing process. Therefore, the main objective of this work was to evaluate the effect of wood machining parameters on the ultimate tensile strength (UTS) of finger-joined black spruce in order to optimize the performance of the product. Parameters investigated in this study were the chip-load and the cutting speed. A feather profile was selected with an isocyanate-based adhesive and an end-pressure of 3.43 MPa. A factorial analysis showed a statistically significant interaction between cutting speed and chip-load on the UTS. Within the range of values studied, the cutting speed was the most significant variable affecting finger-joined black spruce. The influence of chip-load on the tensile strength of finger-joints was lower, being apparent only at lower cutting speeds. Results indicated that suitable finger-jointing could be achieved within a range of 1676 m/min and 2932 m/min of cutting speeds with a chip-load between 0.64 mm and 1.14 mm. However, within this range the best result was obtained at 2932 m/min cutting speed and 0.64 mm chip-load. Scanning microscope image analysis of the damaged cells confirmed the effect of cutting speed on the finger-jointing process. In general, the depth of damage was more severe as the cutting speed increased. © 2004 by the Society of Wood Science and Technology.