Drilling tool

Abstract

Provided is a drilling tool, capable of preventing the cuttings from coiling. Even a drill with a small diameter can have a relatively long anti-damaging lifetime and realize excellent hole-site precision, stable drill processing, and excellent practical applicability. The tail end of the tool body is provided with one or a plurality of cutting edges. The periphery of the tool body is provided with a plurality of helical chip rooms in the direction toward base end side from tail end of the tool. The chip rooms comprise one main groove and more than one auxiliary grooves, wherein the auxiliary grooves are connected with the main groove at the midway section of the main groove. Moreover, the helical angles of the main groove and the auxiliary grooves are designed to have roughly equal angles from the connection setting section set by the connection between the main groove and the auxiliary grooves. The length of the auxiliary grooves is designed to be 50% to 95% of the length of the main groove. Also, the auxiliary grooves are set to be parallel to the main groove within a range from the connection setting section to a predetermined position away from the terminal of the main groove.

Description

technical field [0001] The invention relates to a drilling tool. Background technique [0002] In the drilling process of printed circuit boards (PCB), use such as figure 1 A drill composed of a drill body A having a cutting edge C and a shank B as shown. Depending on the application, the size of the drill varies, but generally speaking, drills with a diameter of 0.7 mm or less are used. [0003] Specifically, on the blade C, such as figure 2 As shown, a helical chip flute 22 is formed on the outer periphery of the main body 20 from the drill tip to the base end side. The cutting edge 21 is formed at the intersecting ridgeline portion (for example, refer to Patent Documents 1 and 2). In addition, in the figure, reference numeral 25 is a second relief surface, and the second relief surface 25 is continuously provided on the rear side of the first relief surface 24 in the tool rotation direction, d' is a tool diameter, and l' is a flute The groove length, α' is the helix...

AI Technical Summary

Problems solved by technology

[0013] In addition, although, for example, Patent Document 4 discloses a technique in which, on a PCB drill having two cutting edges and two chip flutes, the chip flutes are merged at a position retreated by a predetermined amount from the tip, A groove is formed behind the meeting point, thereby improving the rigidity of the drill, but Patent Document 4 does not mention the winding of chips, and the above-mentioned requirements cannot be met.

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