Drilling tool

Abstract

The invention provides an unprecedented drilling tool of strong usefulness. Despite a very small diameter, the drilling tool has no tendency to break, so frequent replacement is no use . Production and inspection can be readily managed due to a simple shape of the drilling tool which has one or plural spiral-shaped scrap exhaust grooves (1, 2). A flat drill point surface(5) not provided with a crest line placed crosswise to a tool central axis, is arranged on the top part of the drilling tool.

Description

technical field [0001] The invention relates to a drilling tool. Background technique [0002] Drilling bits for common printed wiring boards (PCB), such as figure 1 As shown, a pair of chip discharge flutes 21, 22 are provided at a predetermined helix angle (ねじれ angle) β, and the intersecting ridgeline portions 25, 26 of these chip discharge flutes 21, 22 and the first flank surfaces 23, 24 A cutting edge having a predetermined point angle γ' is formed. Numbers 28 and 29 are the second flank among the figures. [0003] therefore, figure 1 The tool has four point faces in total, and the chisel edge 27 is formed near the center of the point of the tool by making each point face (relief face) have a predetermined angle. in addition, figure 1 (a) is a top view, 1(b) is a front view, and 1(c) is a right side view. [0004] However, with the high integration and high density of electronic equipment in recent years, it is necessary to process holes with extremely small diame...

AI Technical Summary

Problems solved by technology

[0005] For example, sometimes a very small diameter drill with a tool diameter of about 0.05 mm is used, but the possibility of breakage is high due to the extremely small rigidity of the tool, and the tool needs to be replaced frequently, or the PCB needs to be laminated and processed at the same time. Countermeasures such as reducing the number of processing times

[0006] In addition, in the visual inspection of the shape of the drill point, it is necessary to measure whether the left and right are balanced (the deflection of the cutting edge and the eccentricity of the chisel edge) to judge whether it is acceptable, but if the diameter becomes smaller, not only processing is troublesome, but also this inspection becomes troublesome.

[0007] Therefore, the current situation is that, for example, in Patent Document 1, although a predetermined structure of a single-blade drill that can ensure rigidity is disclosed even if the tool diameter is small, sufficient breakage life cannot be obtained.

In addition, since there are multiple drill point faces, the pass / fail inspection is troublesome as in the past

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