Cutting speed and feed-per-knife effects on surface quality of cants produced by a chipper-canter

The effects of cutting speed (CS) and feed-per-knife (FK) on the surface quality of black spruce (Picea mariana [Mill.] B.S.P.) cants processed by a chipper-canter were evaluated. Nine matched groups of logs were studied at 20, 25, and 30 m/s of CS, and 19, 25, and 32 mm of FK. Each log was processed at frozen and unfrozen conditions. Knots and grain angle measurements were taken on the cant surfaces after machining. The quality of cants was assessed utilizing waviness, roughness, and torn grain. The results showed that the surface quality was affected by CS and FK. Surface quality improved as FK decreased, likely due to decreasing cutting forces. The waviness tended to improve as CS increased, which could be partly due to the reduction of the non-cutting period between knives at higher CS. The waviness and depth of torn grain were similar for frozen and unfrozen logs. Surface quality varied within the cant, being generally poorer in the lower half. Knots and orientation of spiral grain (left-handed) contributed to diminishing the quality of surfaces. Finally, the results of correlations and regression analyses showed that optimizing the cutting conditions to decrease waviness should also reduce the depth of torn grain.