DRILL - SUMITOMO ELECTRIC INDUSTRIES

Title:

DRILL

Document Type and Number:

WIPO Patent Application WO/2013/099841

Kind Code:

A1

Abstract:

The present invention addresses the problem of producing no cylindrical burrs at the outlet of a drilled hole of a metal layer even when the hole is drilled with the metal layer on bottom by a drill used for drilling in stacked FRP and metal plates, thereby making it possible to obtain the hole of high quality. A cutting edge (3) is configured from at least two portions of a rotation center-side edge portion (3a) and an outer periphery-side edge portion (3c), at the leading end of the body (1) of a twist drill in which the point angles of the respective edge portions become smaller in stages from the rotation center-side edge portion (3a) to the outer periphery-side edge portion (3c), a small-diameter portion (6) having an outer diameter smaller than a drill diameter is provided, the cutting edge (3) having a changing point angle is provided in the smaller-diameter portion, and a flat cutting edge (8) having an inclination angle (β) of 30° or less with respect to a line normal to the axis is provided in a step portion formed between the small-diameter portion (6) and a large-diameter portion (7).

Inventors:

OKA HISAO (JP)
SATO YOSHIJI (JP)
MEGURO KIICHI (JP)
TAMURA JUNICHI (JP)
SUZUKI SATOSHI (JP)

Application Number:

PCT/JP2012/083417

Publication Date:

July 04, 2013

Filing Date:

December 25, 2012

Export Citation:

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Assignee:

SUMITOMO ELECTRIC INDUSTRIES (JP)
SUMITOMO ELEC HARDMETAL CORP (JP)
KAWASAKI HEAVY IND LTD (JP)

International Classes:

B23B51/00

Foreign References:

JP2008000836A	2008-01-10
JP2010284783A	2010-12-24
JP2001087919A	2001-04-03
JPS6239915U	1987-03-10
JP2009172708A	2009-08-06
JP2001054810A	2001-02-27
JP2009172708A	2009-08-06

Other References: