Drill and drill head

Abstract

A drill is provided with a drill body that is rotated around the axial line, chip-discharging flutes (2) formed on the periphery of the drill body, and tip edges (7) formed on the intersection ridges between the chip-discharging flutes (2) and the tip surfaces of the drill body. The tip edges (7) have a first lip (21), which extends toward the base end of the axial direction as one follows the lip radially outward, and a second lip (22), which is disposed outside of the first lip (21) in the radial direction. The second lip (22) extends toward the tip in the axial direction or is perpendicular to the axis line as one follows the lip radially outward. The radially inside end of the second lip (22) is disposed on the axially base end side of the radially outside end of the first lip (21), and the radially outside end of the second lip (22) is disposed on a virtual extension (VL) of the first lip (21) that extends radially outward.

Description

technical field [0001] The present invention relates to a drill and a drill head for drilling a workpiece material such as CFRP (carbon fiber reinforced resin) or a composite material obtained by laminating metal plates such as titanium or aluminum on the CFRP; The head is detachably attached to the front end portion of the tool body of the indexable insert drill or is attached to the front end portion of the tool body in a fixed state by brazing or the like. [0002] This application claims to be based on the patent application No. 2014-197097 filed in Japan on September 26, 2014, the patent application No. 2015-150810 filed in Japan on July 30, 2015, and the patent application filed in Japan on September 24, 2015 Priority of No. 2015-187316, the contents of which are incorporated herein. Background technique [0003] Conventionally, drilling with a drill has been performed on workpiece materials such as CFRP (Carbon Fiber Reinforced Resin) used for aircraft parts, or comp...

AI Technical Summary

Problems solved by technology

That is, drilling is performed while expanding the machining hole of the workpiece material in the radial direction, so the diameter shrinkage phenomenon (springback) of the machining hole occurs after machining, and it is difficult to ensure the machining accuracy of the hole.

Specifically, when drilling with a drill, the inner circumference of the processed hole is pressed radially outward to elastically deform it, and the inner circumference of the processed hole recovers from deformation after processing, resulting in a smaller hole diameter than expected, and it is impossible to ensure Inner diameter accuracy

[0016] In addition, since the cutting edge has a long length, the cutting resistance during drilling is large

In addition, since the length of the cutting edge in the direction of the drill axis is long, the stroke (processing length in the direction of drill transmission) during drilling is long, which affects processing efficiency (productivity).

[0017] In the drill of Patent Document 4, the small-diameter portion and the large-diameter portion are aligned along the axial direction of the drill, so the stroke during drilling is long, which affects processing efficiency (productivity).

[0018] In addition, the small-diameter part is short in the axial direction of the drill, so the amount of regrinding cannot be ensured sufficiently, and the tool life is short

[0019] The drill in Patent Document 5 is formed such that the radially outer end of the cutting edge (tip edge) protrudes toward the front end of the drill relative to the portion other than the end, so cutting resistance acts on the end to a large extent, and wear tends to occur. and defect

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