Fundamental Studies on Cutting of the Knot on the Cutting Surface of the Workpiece in Wood Cutting (II) Effects of the Small Round Knot on the Cutting Surface of the Workpiece upon the Cutting Force in Oblique Cutting of Wood Parallel to the Grain

摘要

In the wood cutting process with a knife equipped with a chip breaker for making the smooth workpiece-surface, it is important to obtain the optimum conditions of sharpness angle of the chip breaker (βB), the distance between the knife edge and the chip breaker edge (ℓK-B) and the inclination angle of the knife (ik) and to investigate the changes of the cutting-force components acting on the face of a knife equipped with a chip braker with βB, ℓK-B, ik, the grain angle of the workpiece (φ1) and the knot on the cutting surface of the workpiece. In order to obtain quantitative information on them, the basic oblique cutting tests, in which the materials used were air-dried wood boards of hinoki (Chamaedyparis obtusa ENDLICHER) and sugi (Cryptomeria japonica D.Don), were pergormed using the knife as shown in Figs. 2～3 and the same experimental apparatus as used in the previous reports. The test specimens, which were fixed to the experimental apparatus equipped with a three-dimensional elasticring dynamoneter, were cut during the feeding of the knife equipped with a chip breaker (Figs. 3～6).The components and the resultant force were measured.Using these results, the effects of ik and the workpice clarified (Figs.7(a)～8(b)). Characteristics of the cutting of the knot on the workpiece surface are discussed, comparing the cutting of the workpiece without a knot.