EP0880425A1 - Process for manufacturing inserts with holes for clamping - Google Patents

Process for manufacturing inserts with holes for clamping

Info

Publication number
EP0880425A1
EP0880425A1 EP97903702A EP97903702A EP0880425A1 EP 0880425 A1 EP0880425 A1 EP 0880425A1 EP 97903702 A EP97903702 A EP 97903702A EP 97903702 A EP97903702 A EP 97903702A EP 0880425 A1 EP0880425 A1 EP 0880425A1
Authority
EP
European Patent Office
Prior art keywords
plug
cemented carbide
hole
clamping
sintered
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP97903702A
Other languages
German (de)
French (fr)
Inventor
Scott M. Packer
Peter Littecke
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sandvik AB
Smith International Inc
Original Assignee
Sandvik AB
Smith International Inc
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 Sandvik AB, Smith International Inc filed Critical Sandvik AB
Publication of EP0880425A1 publication Critical patent/EP0880425A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F2005/001—Cutting tools, earth boring or grinding tool other than table ware
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F5/00—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product
    • B22F5/10—Manufacture of workpieces or articles from metallic powder characterised by the special shape of the product of articles with cavities or holes, not otherwise provided for in the preceding subgroups
    • B22F2005/103—Cavity made by removal of insert

Definitions

  • the present invention relates to the high pressure/high temperature, HP/HT, process for making polycrystalline diamond or cubic boron nitride cutting inserts. More particularly, the invention relates to certain modifications in the HP/HT process which results in cutting inserts with improved production economy and clamping possibilities.
  • cBN cubic boron nitride
  • the inserts used in such operations are either so called PCD (polycrystalline diamond compact) or PcBN (polycrystalline cubic boron nitride compact) comprising a cemented carbide body with a diamond or cBN layer applied at such high temperature and pressure where diamond or cBN is the stable phase or the inserts are provided with diamond or cBN bodies in at least one corner or along an edge generally fastened by brazing.
  • PCD polycrystalline diamond compact
  • PcBN polycrystalline cubic boron nitride compact
  • CONFIRMATION COPY hole followed by wire cutting to make the actual size hole. In this way only straight holes can be made. Holes cannot be cut to satisfy e.g. holes with a chamfer section.
  • making the hole is accomplished by providing a cemented carbide blank with a hole.
  • the hole is provided with a plug consisting of cemented carbide surrounded by a sleeve of a refractory material such as niobium.
  • the plug is easily removed by e.g. chemical leaching of the refractory metal and the plug is removed.
  • Figure 1 is a sectional view of the HP/HT cell as modified by the improvement of the present invention.
  • Figure 2 is an exploded perspective view of the method of the present invention.
  • HP/HT-conditions The assembly consists of a can 11 comprising a cylindrical sleeve 12 and caps 13 of shield metal selected from a group consisting of Zr, Ti, Ta, Nb and Mo.
  • a sintered cemented carbide blank 16 with a hole in it is placed in the cup 12.
  • the hole can be cylindrical but it can also have other shapes such as completely or partly tapered or chamfered on one or both sides of the blank.
  • the hole is provided with a plug with the same geometry as the hole.
  • the plug consists of cemented carbide preferably with essentially the same composition as that of the cemented carbide 25 blank or ceramic surrounded by a sleeve 20 of a refractory metal, preferably Nb, with a wall thickness of 0.25-0.5 mm.
  • a mixture containing diamond or cBN powder is filled into the cell e.g. so as to form a top layer or in grooves as disclosed in US Patent Application 08/446,487 and 08/446,490 or in any other desirable way.
  • the cell is closed and placed in the HP/HT apparatus.
  • the pressure and temperature is increased to the area where diamond or cBN is stable for a sufficient time for sintering to occur.
  • the charge is then allowed to cool under pressure for a short period of time and after the pressure is relieved the compact is recovered.
  • the plug can be removed by electro discharge machining.
  • the plug is removed mechanically or chemically e.g. Nb is removed using KOH.
  • the cemented carbide plug 23 can be reused.
  • the compact is ground to desired final shape, circular, triangular or square, and dimension.
  • a cemented carbide cylindrical disc with composition WC + 16 wt-% Co with diameter of about 22 mm, thickness 6 mm and a central hole with a diameter of 4 mm and with four grooves equidistantly located along the peripheral surface of the blank was prepared.
  • the grooves had an essentially semicircular cross section with a diameter of about 4 mm.
  • the cemented carbide disc was placed in a cup of Nb.
  • a plug was squeezed consisting of a 3 mm diameter cemented carbide cylinder with composition WC + 16 % Co in a tube of Nb with wall thickness 0.5 mm.
  • the grooves were filled with a cBN powder mixture with a composition corresponding to Megadiamond commercial grade MN50 and after that the container was sealed and treated at high temperature and high pressure according to the process described in US 5,115,697. After cooling the compact was recovered. The plug was removed chemically by leaching in a solution of liquid KOH. The blank was then ground to inserts style ⁇ NGA 120408 with a central hole that could firmly be clamped to a tool holder.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Powder Metallurgy (AREA)
  • Polishing Bodies And Polishing Tools (AREA)
  • Drilling Tools (AREA)
  • Laminated Bodies (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)

Abstract

According to the present invention there is provided a method of making a cutting insert with a hole for clamping to a tool holder wherein a superhard abrasive material is sintered and simultaneously bonded to a sintered cemented carbide body with a hole inside a container under elevated pressure and temperature conditions. During sintering the hole is filled with a plug which after sintering is removed.

Description

Process for manufacturing inserts with holes for clamping
Field of Invention
The present invention relates to the high pressure/high temperature, HP/HT, process for making polycrystalline diamond or cubic boron nitride cutting inserts. More particularly, the invention relates to certain modifications in the HP/HT process which results in cutting inserts with improved production economy and clamping possibilities.
Prior art
For machining of several non ferrous alloys like brass, magnesium and aluminium, diamond is the best tool material whereas cubic boron nitride (cBN) is very well suited for machining hardened steel, chilled cast iron and cast iron at elevated speeds.
The inserts used in such operations are either so called PCD (polycrystalline diamond compact) or PcBN (polycrystalline cubic boron nitride compact) comprising a cemented carbide body with a diamond or cBN layer applied at such high temperature and pressure where diamond or cBN is the stable phase or the inserts are provided with diamond or cBN bodies in at least one corner or along an edge generally fastened by brazing.
The method for manufacturing such inserts has been described in e.g. U.S. Patents 3,745,623, 3,743,489 and 4,525,179 and in US Patent Application 08/446,487 and 08/446,490 and such descriptions are incorporated herein by reference.
Many inserts used for machining have holes in the centre to ensure best possible clamping to the tool holder. In case of brazed inserts this can be achieved by brazing a PCD/CBN tip to a body that already has a hole in it. Otherwise the hole has to be cut afterwards which is costly since cutting usually involves plunge EDM to start a small
CONFIRMATION COPY hole followed by wire cutting to make the actual size hole. In this way only straight holes can be made. Holes cannot be cut to satisfy e.g. holes with a chamfer section.
Objects and summary of the invention
It is an object of the present invention to avoid or alleviate the problems of the prior art.
It is further an object to provide a method of making holes in blanks subjected to treatment at such high pressures and temperatures where diamond or cBN is stable. According to the presently claimed invention making the hole is accomplished by providing a cemented carbide blank with a hole. During the HP/HT-treatment the hole is provided with a plug consisting of cemented carbide surrounded by a sleeve of a refractory material such as niobium. After the HP/HT-treatment the plug is easily removed by e.g. chemical leaching of the refractory metal and the plug is removed.
Brief description of the drawings
Figure 1 is a sectional view of the HP/HT cell as modified by the improvement of the present invention.
Figure 2 is an exploded perspective view of the method of the present invention.
Detailed description of the invention
Techniques for simultaneously applying both high pressure and high temperature in this type of apparatus are well known in the art. Referring now to figure 1 the HP/HT- cell 10 fits within the space in the apparatus subjected to
HP/HT-conditions . The assembly consists of a can 11 comprising a cylindrical sleeve 12 and caps 13 of shield metal selected from a group consisting of Zr, Ti, Ta, Nb and Mo. A sintered cemented carbide blank 16 with a hole in it is placed in the cup 12. The hole can be cylindrical but it can also have other shapes such as completely or partly tapered or chamfered on one or both sides of the blank. The hole is provided with a plug with the same geometry as the hole. Preferably, the plug consists of cemented carbide preferably with essentially the same composition as that of the cemented carbide 25 blank or ceramic surrounded by a sleeve 20 of a refractory metal, preferably Nb, with a wall thickness of 0.25-0.5 mm.
A mixture containing diamond or cBN powder is filled into the cell e.g. so as to form a top layer or in grooves as disclosed in US Patent Application 08/446,487 and 08/446,490 or in any other desirable way. The cell is closed and placed in the HP/HT apparatus. The pressure and temperature is increased to the area where diamond or cBN is stable for a sufficient time for sintering to occur. The charge is then allowed to cool under pressure for a short period of time and after the pressure is relieved the compact is recovered.
The plug can be removed by electro discharge machining. Preferably, however, the plug is removed mechanically or chemically e.g. Nb is removed using KOH. In the preferred embodiment the cemented carbide plug 23 can be reused. Finally, the compact is ground to desired final shape, circular, triangular or square, and dimension.
Example
A cemented carbide cylindrical disc with composition WC + 16 wt-% Co with diameter of about 22 mm, thickness 6 mm and a central hole with a diameter of 4 mm and with four grooves equidistantly located along the peripheral surface of the blank was prepared. The grooves had an essentially semicircular cross section with a diameter of about 4 mm. The cemented carbide disc was placed in a cup of Nb. Into the hole of the disc a plug was squeezed consisting of a 3 mm diameter cemented carbide cylinder with composition WC + 16 % Co in a tube of Nb with wall thickness 0.5 mm. The grooves were filled with a cBN powder mixture with a composition corresponding to Megadiamond commercial grade MN50 and after that the container was sealed and treated at high temperature and high pressure according to the process described in US 5,115,697. After cooling the compact was recovered. The plug was removed chemically by leaching in a solution of liquid KOH. The blank was then ground to inserts style ΞNGA 120408 with a central hole that could firmly be clamped to a tool holder.

Claims

Claims
I. A method of making a cutting insert with a hole for clamping to a tool holder wherein a superhard abrasive material is sintered and simultaneously bonded to a sintered cemented carbide body with a hole inside a con¬ tainer under elevated pressure and temperature conditions, the improvement wherein said hole during sintering is filled with a plug which after the sintering is removed. 2. A method according to claim 1 where the plug com¬ prises a refractory metal.
3. A method according to claim 1 where the plug com¬ prises a cemented carbide.
4. A method according to claim 1 further comprising removing the plug by chemical leaching.
5. A method according to claim 1 further comprising removing the plug by electrodischarge machining of the plug from the compact.
6. A method according to claim 3 wherein the cemented carbide of the plug has essentially the same composition as that of the body.
7. A method according to claim 1 wherein the plug comprises a cemented carbide blank surrounded by a sleeve of a refractory material. 8. A method according to claim 7 wherein the cemented carbide of the plug has essentially the same composition as that of the body.
9. A method according to claim 8 wherein the refractory metal is Nb. 10. A method according to claim 9 wherein the Nb is removed by chemical leaching by KOH.
II. A method according to claim 1 wherein said su- perabrasive material comprises polycrystalline diamond crystals. 12. A method according to claim 1 wherein said su¬ perabrasive material comprises cubic boron nitride crystals.
13. A method of making a cutting insert with a hole for clamping to a tool holder wherein a superabrasive material is sintered with a hole inside a container under elevated pressure and temperature conditions, the improvement wherein said hole during sintering is filled with a plug which after the sintering is removed. 14. A method according to claim 13 where the plug comprises a refractory metal.
15. A method according to claim 13 where the plug comprises a cemented carbide.
16. A method according to claim 13 further comprising removing the plug by chemical leaching.
17. A method according to claim 13 further comprising removing the plug by electrodischarge machining of the plug from the compact.
18. A method according to claim 13 wherein the plug comprises a cemented carbide blank surrounded by a sleeve of a refractory material.
19. A method according to claim 20 wherein the re¬ fractory metal is Nb.
20. A method according to claim 21 wherein the Nb is removed by chemical leaching by KOH.
EP97903702A 1996-02-14 1997-02-12 Process for manufacturing inserts with holes for clamping Withdrawn EP0880425A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US60163196A 1996-02-14 1996-02-14
US601631 1996-02-14
PCT/SE1997/000223 WO1997029885A1 (en) 1996-02-14 1997-02-12 Process for manufacturing inserts with holes for clamping

Publications (1)

Publication Number Publication Date
EP0880425A1 true EP0880425A1 (en) 1998-12-02

Family

ID=24408200

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97903702A Withdrawn EP0880425A1 (en) 1996-02-14 1997-02-12 Process for manufacturing inserts with holes for clamping

Country Status (7)

Country Link
EP (1) EP0880425A1 (en)
JP (1) JP2002514977A (en)
KR (1) KR19990082527A (en)
CN (1) CN1064878C (en)
AU (1) AU709461B2 (en)
WO (1) WO1997029885A1 (en)
ZA (1) ZA971237B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6120570A (en) * 1996-02-14 2000-09-19 Smith International Process for manufacturing inserts with holes for clamping
US6655234B2 (en) 2000-01-31 2003-12-02 Baker Hughes Incorporated Method of manufacturing PDC cutter with chambers or passages
US7322776B2 (en) 2003-05-14 2008-01-29 Diamond Innovations, Inc. Cutting tool inserts and methods to manufacture
JP4782672B2 (en) 2003-06-03 2011-09-28 サンドビック インテレクチュアル プロパティー アクティエボラーグ Indexable cutting insert and method of manufacturing the cutting insert
US20050271483A1 (en) 2004-06-02 2005-12-08 Sandvik Ab Indexable cutting inserts and methods for producing the same
US7493965B1 (en) 2006-04-12 2009-02-24 Us Synthetic Corporation Apparatuses and methods relating to cooling a subterranean drill bit and/or at least one cutting element during use
CN110860693A (en) * 2019-11-28 2020-03-06 中国有色桂林矿产地质研究院有限公司 Superhard material polycrystalline multilayer composite sheet with hollow structure and preparation method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2638461A1 (en) * 1988-11-03 1990-05-04 Combustible Nucleaire ABRASIVE COMPOSITE PRODUCT COMPRISING AN ACTIVE PART OF ULTRA-HARD MATERIAL AND METHOD FOR MANUFACTURING SUCH A PRODUCT

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9729885A1 *

Also Published As

Publication number Publication date
CN1220627A (en) 1999-06-23
AU1817697A (en) 1997-09-02
KR19990082527A (en) 1999-11-25
CN1064878C (en) 2001-04-25
AU709461B2 (en) 1999-08-26
ZA971237B (en) 1997-08-25
JP2002514977A (en) 2002-05-21
WO1997029885A1 (en) 1997-08-21

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