Title:
HARD-FILM-COATED DRILL
Document Type and Number:
WIPO Patent Application WO/2020/075698
Kind Code:
A1
Abstract:
Provided is a hard-film-coated drill in which a hard film is coated on the surface of a cemented carbide drill body, wherein a smooth region (4) at the interface between a flank surface (2) and a rake surface (3) is provided to the body. The surface hardness of the hard film used in the coating is within the range of 2000-2500 HV in terms of Vickers hardness. A cross-section of ridgelines for each of a first ridgeline L1 at which the flank surface (2) intersects the region (4) and a second ridgeline L2 at which a margin (6) intersects the flank surface (2) is machined into a rounded shape, and the curvature radius r1 (μm) of the rounded shape of the first ridgeline L1 is set within a range represented by the expression r1 = 0.45 × D + a1 (where 10 ≤ a1 ≤ 25) with respect to the diameter D (mm) of the body. In addition, the curvature radius r2 (μm) of the rounded shape of the second ridgeline L2 is set within a range represented by the expression r2 = 0.65 × D + a2 (where 39 ≤ a2 ≤ 67). Furthermore, the thickness t1 (μm) of the hard film is set within a range represented by the relational expression t1 = 0.8 × ln(D) + a3 (where 0.7 ≤ a3 ≤ 3.0).
Inventors:
NOSHIRO JUNICHI (JP)
HAYASHI RYO (JP)
HAYASHI RYO (JP)
Application Number:
PCT/JP2019/039597
Publication Date:
April 16, 2020
Filing Date:
October 08, 2019
Export Citation:
Assignee:
NACHI FUJIKOSHI CORP (JP)
International Classes:
B23B51/00; B23B27/14; C23C14/06; C23C16/34
Domestic Patent References:
| WO2016043098A1 | 2016-03-24 |
Foreign References:
| JP2000038663A | 2000-02-08 | |||
| JP2014018883A | 2014-02-03 | |||
| CN104960276A | 2015-10-07 | |||
| JP2006307323A | 2006-11-09 |
Attorney, Agent or Firm:
OTANI Kaichi (JP)
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