Studies on Axial Deviation of Hole in Deep Machine-Boring of Wood

概要

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Many deep holes for bolt joints are often required for consumption using a large dimension structural glued laminated timber. In deep machine-boring of this type of timber, axial deviation of the hole frequently occures, and causes difficulty in the bolt joint operation. Therefore, the development of machine boring which prevents axial deviation of hole is important. The objective of this study was to obtain basic information on axial deviation of hole in the deep machine-boring of wood. In this experiment, the effects of knots and bit wear on axial deviation of the hole were examined, and acoustic emission (AE) and power consumption were also measured during the boring process. The main results obtained are as follows: Axial deviation of hole was affected by the annual rings, and became larger with increasing bit wear. In workpieces which had a loose knot, all deep holes deviated in the direction of the loose knot. The average value of both the AE and power consumption became larger with increasing feed per revolution. For the other hand, the average value of the AE were almost unaffected by bit wear, and the average value of power consumption increased slightly by bit wear. A correspondance between axial deviation of hole and the AE or power consumption was not recognized.
九州大学の論文