The effects of wood-fiber directions on acoustic emission in routing

The purpose of this study was to investigate the causes of changes in acoustic emission (AE) signals corresponding to changes in grain orientation in routing. Both the AE signals and the state of cutting process were recorded on high-speed video cameras in an attempt to clarify the relationships between them. Based on the results, it appeared that generated AE was closely related to the state of cutting, as well as the surface finish. The greater the AE, the more severe the cutting performance for inclination angles. The greatest AE was generated when machining failures - fuzzy grains - were produced. Concerning the annual ring angle, the AE count rate, lowest at 0 degrees, slightly increased until 75 degrees, and then rapidly reached its maximum at 90 degrees. Changes in the slope angle had also an effect on the AE signal. The AE count rate, highest at the 0 degrees, gradually decreased until 75-105 degrees, and then increased to reach its maximum at 180 degrees. Moreover, there were correlations between the AE count rate and surface roughness. Therefore, acoustic emission has shown promise for the monitoring of the surface roughness including various cutting conditions.