Title:
SMALL-DIAMETER DRILL AND SMALL-DIAMETER DRILL MANUFACTURING METHOD
Document Type and Number:
WIPO Patent Application WO/2019/054289
Kind Code:
A1
Abstract:
This small-diameter drill has a diameter of 2 mm or less and has a double margin in which a ratio between the margin length and the diameter is 3 or higher. A ratio L/D between a margin length L, in the axial direction from an outer peripheral end of a cutting edge to rear ends of the first and second margin sections, and the diameter D is at least 3. A hard coating composed of a nitride is provided on at least the surface of a chip discharge groove. The surface of the hard coating in the chip discharge groove has a Ssk (skewness) as defined by ISO 25178 of less than 0. In cross-sectional observation of the hard coating, there are five or fewer droplets having an equivalent circular diameter of at least 1.0 μm per 100 μm2.
More Like This:
| JP2004261930 | DRILL |
| WO/2004/013450 | DRILL, IN PARTICULAR MASONRY DRILL |
Inventors:
YOSHIOKA SHOGO (JP)
SASAKI TOMOYA (JP)
SASAKI TOMOYA (JP)
Application Number:
PCT/JP2018/033190
Publication Date:
March 21, 2019
Filing Date:
September 07, 2018
Export Citation:
Assignee:
MITSUBISHI HITACHI TOOL ENG LTD (JP)
International Classes:
B23B51/00
Foreign References:
| JP2004195560A | 2004-07-15 | |||
| JP2017109274A | 2017-06-22 | |||
| JP2014015636A | 2014-01-30 | |||
| JP2007313636A | 2007-12-06 | |||
| JP2016084505A | 2016-05-19 | |||
| US2898612A | 1959-08-11 | |||
| JP2017176807A | 2017-10-05 | |||
| JP2004122295A | 2004-04-22 |
Other References:
See also references of EP 3682993A4
Attorney, Agent or Firm:
MATSUNUMA Yasushi et al. (JP)
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