| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of drilling lumber by which the lumber can efficiently be drilled while hardly chipping a drill small in diameter when many deep and fine holes are drilled in the lumber. SOLUTION: This is a drilling method of lumber in which a large number of fine holes are drilled in the lumber using a drill for the purpose of enhancing permeability inside the lumber. The method is characterized in that, with the diameter of a drill set at 1.0-2.5 mm, the projecting length H of the drill is defined by a relational expression of expression (1) ah(<SP>4</SP>√d) for a drilling depth h and a drill diameter d, wherein the coefficient (a) in the expression (1) is set ≥1.20. A plurality of drills 21 can be individually independently elevated and lowered. When a through knot 3 in a piece of lumber 1 is detected by a through knot detecting means 28, an NC control means controls, based on a detection signal, so that only a drill 21 corresponding to the through knot 3 is not lowered. COPYRIGHT: (C)2010,JPO&INPIT
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