WO2000056490A1 - Drill blank - Google Patents

Drill blank Download PDF

Info

Publication number
WO2000056490A1
WO2000056490A1 PCT/IL2000/000131 IL0000131W WO0056490A1 WO 2000056490 A1 WO2000056490 A1 WO 2000056490A1 IL 0000131 W IL0000131 W IL 0000131W WO 0056490 A1 WO0056490 A1 WO 0056490A1
Authority
WO
WIPO (PCT)
Prior art keywords
shank
flute area
drill blank
carbide
type
Prior art date
Application number
PCT/IL2000/000131
Other languages
French (fr)
Inventor
Rami Bonen
Original Assignee
Micro Tools Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Micro Tools Ltd. filed Critical Micro Tools Ltd.
Priority to DE10084383T priority Critical patent/DE10084383T1/en
Priority to AU29375/00A priority patent/AU2937500A/en
Publication of WO2000056490A1 publication Critical patent/WO2000056490A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B31/00—Chucks; Expansion mandrels; Adaptations thereof for remote control
    • B23B31/005—Cylindrical shanks of tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B51/00—Tools for drilling machines
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B2222/00—Materials of tools or workpieces composed of metals, alloys or metal matrices
    • B23B2222/28—Details of hard metal, i.e. cemented carbide

Definitions

  • the present invention relates generally to drill bits and drill blanks and particularly to a tungsten carbide drill bit and drill blank that has improved toughness and hardness-
  • PCB printed circuit board
  • the present invention seeks to provide an improved drill blank wherein the forward end of the flute area is made of a very hard carbide but the rest of the flute area, as well as the shank, is made of a less brittle carbide.
  • the two different carbide materials preferably tungsten carbide, are not cemented together as in the prior art, but rather are either sintered together in one mold or coextruded.
  • the shank is preferably hollow in order to save on material costs without sacrificing strength, durability and performance.
  • a drill blank including a hollow shank, and a flute area extending forward from the shank.
  • the shank and the flute area are preferably made from tungsten carbide.
  • the shank has a larger diameter than the flute area.
  • the flute area is concentric with the shank within a tolerance of 0.01 mm. Still further in accordance with a preferred embodiment of the present invention the a forward end of the flute area is constructed of a harder material than the rest of the flute area. In accordance with a preferred embodiment of the present invention the forward end of the flute area is sintered together with the rest of the flute area.
  • Fig. 1 is a simplified pictorial illustration of a drill blank constructed and operative in accordance with a preferred embodiment of the present invention.
  • FIG. 1 illustrates a drill blank 10 constructed and operative in accordance with a preferred embodiment of the present invention.
  • Drill blank 10 preferably includes a hollow shank 12 and a flute area 14 extending forward from shank 12.
  • Drill blank 10 is preferably stepped, i.e., shank 12 has a larger diameter than flute area 14.
  • Typical dimensions include a diameter of 1.25 mm for flute area 14 and 3.175 mm for shank 12, and a length of about 11-12 mm for flute area 14 and about 25 mm for shank 12, wherein shank 12 has a bore of 2.30 mm formed therein to make the shank hollow.
  • Flute area 14 is preferably concentric with shank 12 within a tight tolerance, such as no more than 0.01 mm.
  • a forward end 16 of flute area 14 is constructed of a harder material than the rest of the flute area.
  • drill blank 10 is constructed of two types of tungsten carbide, wherein forward end 16 is constructed of a harder tungsten carbide material than the rest of the flute area 14 and shank 12. Different hardness tungsten carbide materials or powders are well known and readily available in the art and the drill manufacturer can choose which two materials are most suitable for the particular application.
  • drill blank 10 may be formed by sintering together two tungsten carbide materials.
  • a mold would be provided shaped to form a drill blank, the mold comprising a shank portion and a flute area portion.
  • the mold is filled with two types of pourable carbide materials, a first type of carbide material being located at a forward end of the flute area portion and the rest of the mold being filled with a second type of carbide material which is not as hard as the first type of carbide material but is less brittle than the first type of carbide material.
  • the two carbide materials are then solidified, preferably by sintering under high pressure and heat, to form a continuous solid carbide drill blank 10.
  • drill blank 10 may be formed by coextrusion.
  • a coextrusion die would be provided for extruding together two different materials wherein one of the materials exits the die forward of the other material.
  • Two types of extrudable carbide materials would be provided, a first type of carbide material and a second type of carbide material, wherein the second type of carbide material is not as hard as the first type of carbide material but is less brittle than the first type of carbide material.
  • the two carbide materials are then coextruded through the coextrusion die to form a continuous solid carbide drill blank 10.
  • the methods of manufacture of the present invention are not limited to sintering and coextrusion but may also include injection molding or other types of molding.
  • Drill blank 10 may be afterwards fashioned into a drill bit by forming a cutting edge at the forward end 16, as is well known in the art.

Abstract

A drill blank (10) including a hollow shank (12), and a flute area (14) extending forward from the shank (12). The shank (12) and the flute area (14) are preferably made from tungsten carbide.

Description

DRILL BLANK
FIELD OF THE INVENTION
The present invention relates generally to drill bits and drill blanks and particularly to a tungsten carbide drill bit and drill blank that has improved toughness and hardness-
BACKGROUND OF THE INVENTION
As is well known in the art of drilling, printed circuit board (PCB) materials tend to wear down drill bits. PCB drill bits are thus made of very hard materials, typically tungsten carbide. Unfortunately, as is also well known in the art, in general, the harder the drill material the more brittle the material becomes. For this reason, drill manufacturers have always had to trade off between hardness and brittleness when choosing a drill bit material.
One method used in the prior art for making carbide drill bits is described in Israel Patent 62342. In this method two carbide materials of different hardnesses are cemented together to form a drill blank or bit. SUMMARY OF THE INVENTION
The present invention seeks to provide an improved drill blank wherein the forward end of the flute area is made of a very hard carbide but the rest of the flute area, as well as the shank, is made of a less brittle carbide. The two different carbide materials, preferably tungsten carbide, are not cemented together as in the prior art, but rather are either sintered together in one mold or coextruded. -Another improvement of the present invention is that the shank is preferably hollow in order to save on material costs without sacrificing strength, durability and performance.
There is thus provided in accordance with a preferred embodiment of the present invention a drill blank including a hollow shank, and a flute area extending forward from the shank. The shank and the flute area are preferably made from tungsten carbide.
In accordance with a preferred embodiment of the present invention the shank has a larger diameter than the flute area.
Further in accordance with a preferred embodiment of the present invention the flute area is concentric with the shank within a tolerance of 0.01 mm. Still further in accordance with a preferred embodiment of the present invention the a forward end of the flute area is constructed of a harder material than the rest of the flute area. In accordance with a preferred embodiment of the present invention the forward end of the flute area is sintered together with the rest of the flute area.
BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawing in which:
Fig. 1 is a simplified pictorial illustration of a drill blank constructed and operative in accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT Reference is now made to Fig. 1 which illustrates a drill blank 10 constructed and operative in accordance with a preferred embodiment of the present invention.
Drill blank 10 preferably includes a hollow shank 12 and a flute area 14 extending forward from shank 12. Drill blank 10 is preferably stepped, i.e., shank 12 has a larger diameter than flute area 14. Typical dimensions (for illustrative purposes only but are not in any way to be construed to limit the scope of the invention) include a diameter of 1.25 mm for flute area 14 and 3.175 mm for shank 12, and a length of about 11-12 mm for flute area 14 and about 25 mm for shank 12, wherein shank 12 has a bore of 2.30 mm formed therein to make the shank hollow. Flute area 14 is preferably concentric with shank 12 within a tight tolerance, such as no more than 0.01 mm.
A forward end 16 of flute area 14 is constructed of a harder material than the rest of the flute area. In a most preferred embodiment, drill blank 10 is constructed of two types of tungsten carbide, wherein forward end 16 is constructed of a harder tungsten carbide material than the rest of the flute area 14 and shank 12. Different hardness tungsten carbide materials or powders are well known and readily available in the art and the drill manufacturer can choose which two materials are most suitable for the particular application. In accordance with one preferred embodiment of the present invention, drill blank 10 may be formed by sintering together two tungsten carbide materials. In such an embodiment, a mold would be provided shaped to form a drill blank, the mold comprising a shank portion and a flute area portion. The mold is filled with two types of pourable carbide materials, a first type of carbide material being located at a forward end of the flute area portion and the rest of the mold being filled with a second type of carbide material which is not as hard as the first type of carbide material but is less brittle than the first type of carbide material. The two carbide materials are then solidified, preferably by sintering under high pressure and heat, to form a continuous solid carbide drill blank 10. In accordance with another preferred embodiment of the present invention, drill blank 10 may be formed by coextrusion. In such an embodiment, a coextrusion die would be provided for extruding together two different materials wherein one of the materials exits the die forward of the other material. Two types of extrudable carbide materials would be provided, a first type of carbide material and a second type of carbide material, wherein the second type of carbide material is not as hard as the first type of carbide material but is less brittle than the first type of carbide material. The two carbide materials are then coextruded through the coextrusion die to form a continuous solid carbide drill blank 10.
It is appreciated by persons skilled in the art that the methods of manufacture of the present invention are not limited to sintering and coextrusion but may also include injection molding or other types of molding.
Drill blank 10 may be afterwards fashioned into a drill bit by forming a cutting edge at the forward end 16, as is well known in the art.
It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art.

Claims

C L A I M SWhat is claimed is:
1. A drill blank (10) comprising: a hollow shank (12); and a flute area (14) extending forward from said shank (12).
2. The drill blank (10) according to claim 1 wherein said shank (12) and said flute area (14) are made from tungsten carbide.
3. The drill blank (10) according to claim 1 wherein said shank (12) has a larger diameter than said flute area (14).
4. The drill blank (10) according to claim 1 wherein said flute area (14) is concentric with said shank (12) within a tolerance of 0.01 mm.
5. The drill blank (10) according to claim 1 wherein a forward end (16) of said flute area (14) is constructed of a harder material than the rest of the flute area (14).
6. The drill blank (10) according to claim 1 wherein a forward end (16) of said flute area (14) is constructed of a harder tungsten carbide material than the rest of the flute area (14).
7. The drill blank (10) according to claim 6 wherein said forward end (16) of said flute area (14) is sintered together with the rest of said flute area (14).
8. A drill blank (10) comprising: a shank (12); and a flute area (14) extending forward from said shank (12), wherein a forward end (16) of said flute area (14) is constructed of a harder tungsten carbide material than the rest of the flute area (14).
9. The drill blank (10) according to claim 8 wherein said forward end (16) of said flute area (14) is sintered together with the rest of said flute area (14).
10. The drill blank (10) according to claim 8 wherein said shank (12) is hollow.
11. The drill blank (10) according to claim 8 wherein said shank (12) has a larger diameter than said flute area (14).
12. The drill blank (10) according to claim 8 wherein said flute area (14) is concentric with said shank (12) within a tolerance of 0.01 mm.
13. The drill blank (10) according to claim 1 wherein said flute area (14) is formed with a drill bit cutting edge.
14. A method for constructing a drill blank (10), comprising: providing a mold shaped to form a drill blank (10), said mold comprising a shank (12) portion and a flute area (14) portion; filling said mold with two types of pourable carbide materials, a first type of carbide material being located at a forward end (16) of said flute area (14) portion and the rest of the mold being filled with a second type of carbide material which is not as hard as the first type of carbide material but is less brittle than the first type of carbide material; and solidifying the two carbide materials to form a continuous solid carbide drill blank (10), said drill blank (10) comprising a shank (12) and a flute area (14) extending forward from said shank (12), wherein a forward end (16) of said flute area (14) is constructed of the first type of carbide material and the rest of the flute area (14) is constructed of the second type of carbide material.
15. The method according to claim 14 wherein said pourable carbide materials comprise sinterable powders and the step of solidifying comprises sintering the powders.
16. A method for constructing a drill blank (10), comprising: providing a coextrusion die for extruding together two different materials wherein one of the materials exits the die forward of the other material; providing two types of extrudable carbide materials, a first type of carbide material and a second type of carbide material, wherein the second type of carbide material is not as hard as the first type of carbide material but is less brittle than the first type of carbide material; and coextruding the two carbide materials through the coextrusion die to form a continuous solid carbide drill blank (10), said drill blank (10) comprising a shank (12) and a flute area (14) extending forward from said shank (12), wherein a forward end (16) of said flute area (14) is constructed of the first type of carbide material and the rest of the flute area (14) is constructed of the second type of carbide material.
PCT/IL2000/000131 1999-03-21 2000-03-05 Drill blank WO2000056490A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE10084383T DE10084383T1 (en) 1999-03-21 2000-03-05 Drill blank and manufacturing process
AU29375/00A AU2937500A (en) 1999-03-21 2000-03-05 Drill blank

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL129078 1999-03-21
IL12907899A IL129078A0 (en) 1999-03-21 1999-03-21 Drill blank

Publications (1)

Publication Number Publication Date
WO2000056490A1 true WO2000056490A1 (en) 2000-09-28

Family

ID=11072626

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IL2000/000131 WO2000056490A1 (en) 1999-03-21 2000-03-05 Drill blank

Country Status (4)

Country Link
AU (1) AU2937500A (en)
DE (1) DE10084383T1 (en)
IL (1) IL129078A0 (en)
WO (1) WO2000056490A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7226254B2 (en) * 2001-08-29 2007-06-05 Arno Friedrichs Rod-shaped tool for machining a workpiece
US7374374B2 (en) * 2003-09-12 2008-05-20 Seco Tools Ab Tool for chip removal
JP2013188847A (en) * 2012-03-14 2013-09-26 Mitsubishi Materials Corp Hard alloy cutting tool

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3208282A1 (en) * 1981-03-10 1982-10-21 Iscar Ltd., Nahariya Method of joining sintered hard-metal bodies and hard-metal composite products produced thereby
EP0380096A1 (en) * 1989-01-26 1990-08-01 Sumitomo Electric Industries, Ltd. Cemented carbide drill
DE19718275A1 (en) * 1997-05-01 1998-11-05 Nagel Masch Werkzeug Deep drilling tool

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3208282A1 (en) * 1981-03-10 1982-10-21 Iscar Ltd., Nahariya Method of joining sintered hard-metal bodies and hard-metal composite products produced thereby
EP0380096A1 (en) * 1989-01-26 1990-08-01 Sumitomo Electric Industries, Ltd. Cemented carbide drill
DE19718275A1 (en) * 1997-05-01 1998-11-05 Nagel Masch Werkzeug Deep drilling tool

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7226254B2 (en) * 2001-08-29 2007-06-05 Arno Friedrichs Rod-shaped tool for machining a workpiece
US7374374B2 (en) * 2003-09-12 2008-05-20 Seco Tools Ab Tool for chip removal
JP2013188847A (en) * 2012-03-14 2013-09-26 Mitsubishi Materials Corp Hard alloy cutting tool

Also Published As

Publication number Publication date
DE10084383T1 (en) 2002-04-25
IL129078A0 (en) 2000-02-17
AU2937500A (en) 2000-10-09

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