Optimal power consumption and surface quality in the circular sawing process of Douglas-fir wood

Abstract

Optimal cutting conditions that result in high cutting accuracy and low power consumption are critical in lumber recovery and quality for sustainable wood manufacturing. Despite the many research on wood machining for secondary processing applications, less emphasis has been put on the challenges faced in primary sawing applications. These challenges are associated with online monitoring of surface quality through waviness measurement and conducting full-scale wood cutting experiments under extreme conditions. This paper investigated the effect of feed speed, rotation speed, depth of cut, and the average chip thickness on the power consumption and waviness during the sawing process of green Douglas-fir wood. Power consumption and waviness were measured to find the optimal cutting conditions for energy efficient cutting with high cutting accuracy. Waviness was monitored online using laser displacement sensors and the acquired signals were filtered using the wavelet denoising method. The results showed that cutting power and waviness increased with feed speed. While increasing the rotation speed accounted for higher cutting power, it resulted in less waviness. The impacts of rotation speed on cutting power and the waviness of the sawn lumber were discussed. The waviness is significantly greater at the board top as it is close to saw rim, which is characterized by higher blade deflection. For an identical chip thickness, energy efficient cutting was obtained under low-speed conditions, whereas high-speed conditions improved the waviness. There is a trade-off between productivity, cut quality, and power consumption.