SE537723C2 - A grinding tool for machining brittle materials and a process for making a grinding tool - Google Patents

A grinding tool for machining brittle materials and a process for making a grinding tool Download PDF

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Publication number
SE537723C2
SE537723C2 SE1150720A SE1150720A SE537723C2 SE 537723 C2 SE537723 C2 SE 537723C2 SE 1150720 A SE1150720 A SE 1150720A SE 1150720 A SE1150720 A SE 1150720A SE 537723 C2 SE537723 C2 SE 537723C2
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Sweden
Prior art keywords
grinding tool
matrix
volume
particles
abrasive
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Application number
SE1150720A
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Swedish (sv)
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SE1150720A1 (en
Inventor
Stefan Bergh
Ida Johansson
Michael Tholin
Fredrik Westberg
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Slipnaxos Ab
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Application filed by Slipnaxos Ab filed Critical Slipnaxos Ab
Priority to SE1150720A priority Critical patent/SE537723C2/en
Priority to BR112014001447A priority patent/BR112014001447A2/en
Priority to RU2014106604/02A priority patent/RU2594923C2/en
Priority to PCT/SE2012/050842 priority patent/WO2013015737A1/en
Priority to NZ620302A priority patent/NZ620302B2/en
Priority to EP12817725.0A priority patent/EP2734334B1/en
Priority to MYPI2014000176A priority patent/MY169695A/en
Priority to JP2014521596A priority patent/JP5982725B2/en
Priority to AU2012287547A priority patent/AU2012287547B2/en
Priority to CN201280036226.6A priority patent/CN103781596B/en
Priority to US14/233,932 priority patent/US20140227952A1/en
Priority to KR1020147004205A priority patent/KR101861890B1/en
Priority to MX2014000837A priority patent/MX358578B/en
Priority to CA2842534A priority patent/CA2842534A1/en
Publication of SE1150720A1 publication Critical patent/SE1150720A1/en
Priority to IL230524A priority patent/IL230524A/en
Priority to ZA2014/00915A priority patent/ZA201400915B/en
Publication of SE537723C2 publication Critical patent/SE537723C2/en

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    • 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
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
    • B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
    • B24D3/08—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements for close-grained structure, e.g. using metal with low melting point
    • 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
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/04—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic
    • B24D3/06—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially inorganic metallic or mixture of metals with ceramic materials, e.g. hard metals, "cermets", cements
    • 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
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/18—Non-metallic particles coated with metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D18/00—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for
    • B24D18/0009—Manufacture of grinding tools or other grinding devices, e.g. wheels, not otherwise provided for using moulds or presses
    • 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
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/20—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially organic
    • B24D3/22—Rubbers synthetic or natural
    • B24D3/24—Rubbers synthetic or natural for close-grained structure
    • 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
    • B24D3/02—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent
    • B24D3/20—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents the constituent being used as bonding agent and being essentially organic
    • B24D3/28—Resins or natural or synthetic macromolecular compounds
    • 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
    • B24D3/34—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties
    • B24D3/342—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents characterised by additives enhancing special physical properties, e.g. wear resistance, electric conductivity, self-cleaning properties incorporated in the bonding agent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
    • B24D5/02—Wheels in one piece
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D5/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor
    • B24D5/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting only by their periphery; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D7/00—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor
    • B24D7/06—Bonded abrasive wheels, or wheels with inserted abrasive blocks, designed for acting otherwise than only by their periphery, e.g. by the front face; Bushings or mountings therefor with inserted abrasive blocks, e.g. segmental
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
    • B24D99/00—Subject matter not provided for in other groups of this subclass
    • B24D99/005—Segments of abrasive wheels
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C26/00—Alloys containing diamond or cubic or wurtzitic boron nitride, fullerenes or carbon nanotubes
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C32/00—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ
    • C22C32/0047—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents
    • C22C32/0068—Non-ferrous alloys containing at least 5% by weight but less than 50% by weight of oxides, carbides, borides, nitrides, silicides or other metal compounds, e.g. oxynitrides, sulfides, whether added as such or formed in situ with carbides, nitrides, borides or silicides as the main non-metallic constituents only nitrides
    • 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
    • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
    • B22F2998/10—Processes characterised by the sequence of their steps

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Polishing Bodies And Polishing Tools (AREA)

Abstract

SAMMANDRAG Uppfinningen avser ett slipverktyg 1 for bcarbetning av sproda material. Slipverktyget 1 har en karna 2 och en abrasiv kant 4. Den abrasiva kanten 4 innefattar abrasiva partiklar 5 inbaddade i en grundmassa 6. Grundmassan 6 innefattar ett metalliskt bindemedel och mojligen aven ett polymert bindemedel. Det metalliska bindemedlet innefattar kiselnitrid i en mangd som utgor 0.02 — 5.0 volym-% av det metalliska bindemedlet. Uppfinningen avser aven ett forfarande for framstallning av slipverktyget. I forfarandet blandas abrasiva partiklar med metallpulver och kiselnitrid och blandningen sintras. Polymerpulver kan ocksa tillsattas fOre sintring. SUMMARY The invention relates to a grinding tool 1 for processing spray material. The abrasive tool 1 has a core 2 and an abrasive edge 4. The abrasive edge 4 comprises abrasive particles 5 embedded in a matrix 6. The matrix 6 comprises a metallic binder and possibly also a polymeric binder. The metallic binder comprises silicon nitride in an amount of 0.02 - 5.0% by volume of the metallic binder. The invention also relates to a method for manufacturing the grinding tool. In the process, abrasive particles are mixed with metal powder and silicon nitride and the mixture is sintered. Polymer powder can also be added before sintering.

Description

ETT SLIP VERKTYG FOR BEARBETNING AV SPRODA MATERIAL SAMT ETT FORFARANDE FOR FRAMSTALLNING AV ETT SLIP VERKTYG UPPFINNINGENS OMRADE Uppfinningen avser ett slipverktyg, i synnerhet ett slipverktyg for att slipa harda och/eller sproda material sasom volframkarbid. Slipverktyget kan i synnerhet vara en slipskiva. Uppfinningen avser aven ett forfarande for att framstalla ett sa.dant slipverktyg. FIELD OF THE INVENTION The invention relates to a grinding tool, in particular a grinding tool for grinding hard and / or brittle materials such as tungsten carbide. The grinding tool can in particular be a grinding wheel. The invention also relates to a method for manufacturing such a grinding tool.

BAKGRUND TILL UPPFINNINGEN Slipverktyg sasom slipskivor anvands fOr bearbetning av sproda material. Ett omrade dar sadana slipverktyg anvands är bearbetning av sadana verktyg som är gjorda av hardmetall (volframkarbid). Till exempel kan slipverktyg anvandas i bearbetningsoperationer i vilka borrar eller frasverktyg formas genom slipning. Om det arbetsstycke som skall formas är gjort av ett hart material sasom volframkarbid maste det abrasiva verktyget ha abrasiva partiklar av ett mycket hart material. I praktiken innebar detta normalt att de abrasiva partiklama är diamantpartiklar eller kom av kubisk bomitrid. Diamanter eller kom av kubisk bomitrid for detta syfte är kommersiellt tillgangliga och kan anses som standardkomponenter. Diamanter for detta syfte kan typiskt ha en genomsnittlig partikelstorlek pa 501..tm (storleken pa partiklama varierar givetvis) och har ett flertal skarpa kanter som kan skara i harda material sasom volframkarbid. BACKGROUND OF THE INVENTION Grinding tools such as grinding wheels are used for machining spray materials. One area where such grinding tools are used is the machining of such tools which are made of cemented carbide (tungsten carbide). For example, grinding tools can be used in machining operations in which drills or milling tools are formed by grinding. If the workpiece to be formed is made of a hard material such as tungsten carbide, the abrasive tool must have abrasive particles of a very hard material. In practice, this normally meant that the abrasive particles were diamond particles or grains of cubic bomitride. Diamonds or cubes of cubic bomitride for this purpose are commercially available and can be considered as standard components. Diamonds for this purpose can typically have an average particle size of 501..tm (the size of the particles varies, of course) and have a number of sharp edges that can cut into hard materials such as tungsten carbide.

En kand typ av slipverktyg for detta andamal är en slipskiva med en kama som kan vara gjord av, till exempel, ett metalliskt material sasom stal eller aluminium. Kaman kan aven vara gjord av ett icke-metalliskt material sasom ett polymermaterial. Kaman kan vara utformad som en skiva vilken kan vara monterad pa en verktygsspindel for rotation kring den skivformade metallkarnans axel. En abrasiv kant omger karnan och är forbunden med kaman. Den abrasiva kanten kan innefatta abrasiva partiklar som är inbaddade i en grundmassa med ett eller flera bindemedel. Materialet som anvands i den abrasiva kanten är normalt dyrare an materialet i karnan. Av det skalet har den abrasiva kanten en mindre utstrackning i radiell riktning an karnan (d.v.s. den abrasiva kanten är normalt en mindre del av slipskivan eftersom den är dyrare). A known type of grinding tool for this purpose is a grinding wheel with a cam which may be made of, for example, a metallic material such as steel or aluminum. The comb may also be made of a non-metallic material such as a polymeric material. The cam may be formed as a disc which may be mounted on a tool spindle for rotation about the axis of the disc-shaped metal core. An abrasive edge surrounds the karnan and is connected to the kaman. The abrasive edge may comprise abrasive particles embedded in a matrix with one or more adhesives. The material used in the abrasive edge is usually more expensive than the material in the karnan. Of that shell, the abrasive edge has a smaller extent in the radial direction than the karnan (i.e. the abrasive edge is normally a smaller part of the grinding wheel because it is more expensive).

Under slipning nots den abrasiva kanten gradvis ner till dess att den är forbrukad och slipskivan inte langre kan anvandas. 1 Kanda bindemedel for abrasiva kanter pa slipskivor innefattar polymera bindemedel som, till exempel, Bakelit. Altemativt kan bindemedlet vara ett keramiskt bindemedel. Det är aven kant att anvanda metalliska bindemedel, i synnerhet bindemedel av brons som framstallts genom sintring. I sadana sintringsoperationer sintras metallpulver innehallande koppar och tenn tillsammans med abrasiva partiklar sasom diamantpartiklar eller kom av kubisk bomitrid. Ibland kan silver tillsattas sâ att bronset innehaller koppar (Cu), tenn (Sn) och silver (Ag). I det forflutna har praktisk erfarenhet visat att legeringar av Cu/Sn/Ag fungerar val som bindemedel air slipmedel och att sadana bindemedel fungerar val under slipning. Aven om den exakta anledningen till detta inte har fullstandigt forstatts tror uppfinnarna att forbattrad varmeledning som fetid av tillsatsen av silver kan forklara varfor bronslegeringar som innehaller silver kan fungera val som bindemedel for slipmedel. Eftersom silver är dyrt kan emellertid andra bronslegeringar anvandas for att minska kostnaden och den nu foreliggande uppfinningen är tillamplig aven pa bronslegeringar utan silver. During grinding, the abrasive edge is gradually lowered until it is used up and the grinding wheel can no longer be used. Kanda binders for abrasive edges on grinding wheels include polymeric binders such as, for example, Bakelite. Alternatively, the binder may be a ceramic binder. It is also advisable to use metallic binders, in particular bronze binders made by sintering. In such sintering operations, metal powders containing copper and tin are sintered together with abrasive particles such as diamond particles or grains of cubic boron nitride. Sometimes silver can be added so that the bronze contains copper (Cu), tin (Sn) and silver (Ag). In the past, practical experience has shown that alloys of Cu / Sn / Ag function as binders and air abrasives and that such binders act as choices during grinding. Although the exact reason for this has not been fully understood, the inventors believe that improved thermal conductivity as a fetid of the addition of silver may explain why bronze alloys containing silver may act as a binder for abrasives. However, since silver is expensive, other bronze alloys can be used to reduce the cost and the present invention is also applicable to bronze alloys without silver.

Andra kanda bronssammansattningar for detta syfte innefattar koppar/tenn/kobolt (Cu/Sn/Co) och koppar/tenn/nickel (Cu/Sn/Ni). Det har alien foreslagits att bronssammansattningar for detta andamal kan innehalla koppar/tenn/titan (Cu/Sn/Ti). Other known bronze compositions for this purpose include copper / tin / cobalt (Cu / Sn / Co) and copper / tin / nickel (Cu / Sn / Ni). It has been suggested by the alien that bronze compositions for this purpose may contain copper / tin / titanium (Cu / Sn / Ti).

Ytterligare ett 'cant system innehaller hybrider av polymera och metalliska bindemedel i vilka metallpulver sintras tillsammans med polymermaterial sâ att en grundmassa bildas i vilken det polymera bindemedlet och det metalliska bindemedlet (typiskt en bronslegering som beskrivits ovan) är nara sammanflatade med varandra pa mikroskopisk niva. I sadana hybrider bildar vart och ett av det metalliska bindemedlet och det polymera bindemedlet ett natverk och bindemedlens respektive natverk gar in i varandra. En sidan hybridgrundmassa som innefattar bade ett metalliskt bindemedel och ett polymert bindemedel finns beskrivet i till exempel US patent nr. 6063148. A further system contains hybrids of polymeric and metallic binders in which metal powders are sintered together with polymeric material so that a matrix is formed in which the polymeric binder and the metallic binder (typically a bronze alloy described above) are closely intertwined at a microscopic level. In such hybrids, each of the metallic binder and the polymeric binder form a network and the respective networks of the binders merge into each other. A side hybrid matrix comprising both a metallic binder and a polymeric binder is described in, for example, U.S. Pat. 6063148.

Forutom metalliska och polymera bindemedel innehaller sldana hybrider normalt ett eller flera fyllmaterial. Ett sadant fyllmaterial kan vara grafit som anvands for sina smorjande egenskaper. In addition to metallic and polymeric binders, such hybrids normally contain one or more fillers. Such a filler material can be graphite which is used for its lubricating properties.

De abrasiva partiklarna kan ha olika egenskaper. Till exempel kan diamanters skorhet variera beroende pa det syfte for vilket slipverktyget skall anvandas. Egenskaperna hos olika diamanter kan matchas for att stamma overens med egenskaperna hos olika bindemedel (eller hybrider av bindemedel). 2 I ett bra slipverktyg skall de abrasiva partiklarna vara bundna i sin grundmasa pa ett sadant salt att slipverktyget fungerar som Onskat. Det är onskvart att slipverktyget har en god notningsbestandighet sa att det kan anvandas Over en langre period. En god notningsbestandighet är emellertid inte den enda onskvdrda egenskapen och det slipverktyg som har den storsta nOtningsbestandigheten är inte nodvandigtvis det basta valet. Andra onskvarda egenskaper innefattar lag energikonsumtion (d.v.s. att den effekt som krdvs for att driva slipverktyget inte är alltfor hog) samt konstant eller atminstone forutsdgbara prestanda. Om den abrasiva kantens slipande effekt varierar alltfor mycket 10 Over tiden medfor detta problem. Detta är i synnerhet fallet dâ slipverktygets prestanda varierar pa ett sift som är oforutsdgbart. The abrasive particles can have different properties. For example, the cut of diamonds may vary depending on the purpose for which the grinding tool is to be used. The properties of different diamonds can be matched to match the properties of different binders (or hybrids of binders). 2 In a good grinding tool, the abrasive particles must be bound in their matrix to such a salt that the grinding tool functions as desired. It is unfortunate that the grinding tool has a good wear resistance so that it can be used over a longer period. However, good abrasion resistance is not the only undesirable property and the grinding tool having the greatest abrasion resistance is not necessarily the best choice. Other undesirable properties include low energy consumption (i.e. that the power required to drive the grinding tool is not too high) and constant or at least predictable performance. If the abrasive effect of the abrasive edge varies too much 10 Over time this causes a problem. This is especially the case when the performance of the grinding tool varies on a sieve that is unpredictable.

Omfattningen av notningen pa slipverktyget under givna forutsdttningar beror i valdigt hog grad pa egenskaperna hos den grundmassa i vilken de abrasiva partiklarna är inbdddade. Darfor är sammansattningen av grundmassan viktig. The extent of the wear on the grinding tool under given conditions depends to a very high degree on the properties of the matrix in which the abrasive particles are embedded. Therefore, the composition of the matrix is important.

Ndr ett slipverktyg anvdnds for att bearbeta ett arbetsstycke verkar skarpa kanter och hOrn pa de abrasiva partiklarna pa arbetsstycket. Ddrigenom utovas kraft pa abrasiva partiklar som är inbaddade i grundmassan. Under slipningen skadas de abrasiva partiklarna. Sma bitar bryts gradvis loss fran de abrasiva partiklarna sâ att de abrasiva partiklarna gradvis nots ned. Ndr de abrasiva partiklarna i ett omrade av den abrasiva kanten har blivit fullstandigt nedslitna kommer arbetsstycket att direkt mota grundmassan. Grundmassan som sadan är mindre hard an arbetsstycket och nots snabbt ner. Som foljd &dray kommer nya abrasiva partiklar upp till ytan av den abrasiva kanten och kan borja verka pa arbetsstycket. When a grinding tool is used to machine a workpiece, sharp edges and corners appear on the abrasive particles on the workpiece. In this way force is exerted on abrasive particles which are embedded in the matrix. During grinding, the abrasive particles are damaged. Small pieces are gradually broken away from the abrasive particles so that the abrasive particles gradually wear down. When the abrasive particles in an area of the abrasive edge have become completely worn, the workpiece will directly meet the matrix. The matrix as such is less hard than the workpiece and grooves down quickly. As a result, new abrasive particles come up to the surface of the abrasive edge and can begin to act on the workpiece.

Om grundmassan som hailer de abrasiva partiklarna är for svag kan emellertid abrasiva partiklar slitas bort frau grundmassan innan de notts ned. Ndr detta hdnder i en del av den abrasiva kantens yta kommer arbetsstycket att komma i direkt kontakt med den relativt skora grundmassan och slita ned grundmassan i farad. Nar detta sker minskar effektforbrukningen tillfalligt till dess att sà mycket av grundmassan har no-as ned att nya abrasiva partiklar kommer upp till ytan. Som en foljd &ray kommer slipverktygets abrasiva kant att notas ut fortare an vad som annars skulle ha varit fallet. Om driften av slipverktyget programmerats i forvdg kan konsekvensen dray bli att slipningsforfarandet inte fungerar korrekt eftersom slipverktyget har stdllts in att verka utgaende frau_ ett antagande om verktygsdiameter som nu är felaktigt. Detta problem blir allvarligare om den abrasiva kanten nots ut pa ett sdtt som är svart att forutse, till 3 exempel om notning upptrader i plotsliga steg som kommer med oregelbundna mellanrum. However, if the matrix that heals the abrasive particles is too weak, abrasive particles can wear away from the matrix before they wear down. If this happens in a part of the surface of the abrasive edge, the workpiece will come into direct contact with the relatively sparse matrix and tear down the matrix in danger. When this happens, the power consumption decreases temporarily until so much of the matrix has no-as down that new abrasive particles come up to the surface. As a follow-up, the abrasive edge of the grinding tool will be noted faster than would otherwise have been the case. If the operation of the grinding tool is programmed in advance, the consequence may be that the grinding procedure does not work properly because the grinding tool has been set to operate on the basis of an assumption about tool diameter which is now incorrect. This problem becomes more serious if the abrasive edge is notched out in a way that is black to predict, for example if notching occurs in sudden steps that occur at irregular intervals.

Det är ocksd onskvart att den erforderliga effekten for slipningsoperationen kan hallas lag sa att energikonsumtionen under slipning kan minimeras. It is also unfortunate that the required effect for the grinding operation can be kept to a minimum so that the energy consumption during grinding can be minimized.

En annan onskvard egenskap hos slipverktyg är ett Mgt G-tal. G-talet uttrycker forhallandet mellan den materialvolym som avldgnats av slipverktyget fran ett arbetsstycke och den volym som fcirlorats av slipverktyget (nOtningen pd verktyget). Ett 10 bra slipverktyg har ett Mgt G-tal. Another desirable property of grinding tools is a Mgt G-number. The G-number expresses the ratio between the volume of material obtained by the grinding tool from a workpiece and the volume lost by the grinding tool (the wear on the tool). A good grinding tool has a Mgt G number.

Det är dad& ett andamdl for den nu fOreliggande uppfinningen att tillhandahalla ett slipverktyg som har en hog bestandighet mot nothing. Vidare andamal med uppfinningen är att tillhandahalla ett verktyg som nots ned pa ett regelbundet och forutsagbart sat, som har ett ldgt effektbehov och ett Mgt G-tal. Dessa malsattningar uppnas genom den nu foreliggande uppfinningen som skall forklaras i det foljande. It is an object of the present invention to provide a grinding tool which has a high resistance to nothingness. A further object of the invention is to provide a tool which is grounded in a regular and predictable manner, which has a low power requirement and a high G-number. These targets are achieved by the present invention which will be explained in the following.

SAMMANFATTNING AV UPPFINNINGEN Uppfinningen avser ett slipverktyg. Slipverktyget är i synnerhet avsett som ett slipverktyg for att bearbeta harda och/eller sproda material sasom volframkarbid men det uppfinningsenliga slipverktyget skulle ocksd kunna anvandas for att slipa andra material. Slipverktyget innefattar en karna och en abrasiv kant. Den abrasiva kanten innefattar abrasiva partiklar inbaddade i en grundmassa och grundmassan innefattar ett metalliskt bindemedel som är en sintrad bronslegering. Det metalliska bindemedlet utgor 50% - 100% av grundmassans volym. Enligt uppfinningen innehaller det metalliska bindemedlet kiselnitrid i en mangd som utgor 0.02 — 5.0 volym-% av det metalliska bindemedlet eller valfritt 0.1 volym-% — 5.0 volym-% av det metalliska bindemedlet. 30 I utforingsformer av uppfinningen kan grundmassan vidare valfritt innefatta ett polymert bindemedel som har sintrats tillsammans med det metalliska bindemedlet sâ att det polymera bindemedlet och det metalliska bindemedlet bildar ett sammanfogat natverk. 35 I utforingsformer av uppfinningen utgar kiselnitriden 0.3 — 5.0 volym% av det metalliska bindemedlet. Den kan till exempel utgora 0.5 — 5.0 volym-% av det 4 metalliska bindemedlet, 1.0 — 5.0 volym-% av det metalliska bindemedlet eller 0.5 — 3.0 volym-% eller 0.5 — 2.0 volym-%. SUMMARY OF THE INVENTION The invention relates to a grinding tool. The grinding tool is in particular intended as a grinding tool for processing hard and / or spraying materials such as tungsten carbide, but the grinding tool according to the invention could also be used for grinding other materials. The grinding tool comprises a bead and an abrasive edge. The abrasive edge comprises abrasive particles embedded in a matrix and the matrix comprises a metallic binder which is a sintered bronze alloy. The metallic binder constitutes 50% - 100% of the matrix volume. According to the invention, the metallic binder contains silicon nitride in an amount of 0.02 - 5.0% by volume of the metallic binder or optionally 0.1% by volume - 5.0% by volume of the metallic binder. In embodiments of the invention, the matrix may further optionally comprise a polymeric binder which has been sintered together with the metallic binder so that the polymeric binder and the metallic binder form a joined network. In embodiments of the invention, the silicon nitride provides 0.3 - 5.0% by volume of the metallic binder. It may, for example, constitute 0.5 - 5.0% by volume of the 4 metallic binder, 1.0 - 5.0% by volume of the metallic binder or 0.5 - 3.0% by volume or 0.5 - 2.0% by volume.

Kiselnitriden kan vara narvarande i form av korn med en genomsnittlig kornstorlek som foretradesvis är mindre an 10[tm men aven foretradesvis over 0.1[tm. Sadana partiklar kan vara 1250 Tyler Mesh- partiklar. Partiklarna kan saledes innefatta partiklar upp till 10um aven om den genomsnittliga kornstorleken är mindre. The silicon nitride may be present in the form of grains with an average grain size which is preferably less than 10 [mu] m but also preferably above 0.1 [mu] m. Such particles can be 1250 Tyler Mesh particles. Thus, the particles may include particles up to 10 microns even if the average grain size is smaller.

Nar ett polymert bindemedel är en del av grundmassan kan det polymera bindemedlet innefatta polyimid eller vara helt eller nastan helt av polyimid. When a polymeric binder is part of the matrix, the polymeric binder may comprise polyimide or be wholly or almost entirely of polyimide.

Grundmassan kan valfritt vidare innefatta fyllmaterial sasom grafit. Grafit har smorjande egenskaper som kan vara onskvarda under slipning. The matrix may optionally further comprise fillers such as graphite. Graphite has lubricating properties that can be unsightly during grinding.

Det metalliska bindemedlet är fOretradesvis en bronslegering som innefattar koppar, tenn och silver. The metallic binder is preferably a bronze alloy comprising copper, tin and silver.

De abrasiva partiklarna kan vara, till exempel, diamantpartiklar eller partiklar av kubisk bornitrid. For bade diamanter och kubisk bornitrid kan de abrasiva partiklarna ha en genomsnittlig partikelstorlek som ligger i intervallet zium — 181[tm. I Manga realistiska utforingsformer kan de abrasiva partiklama ha en storlek i intervallet 46um — 91um. I utforingsformer av uppfinningen kan de abrasiva partiklarna ha en belaggning avkoppar eller nickel. The abrasive particles may be, for example, diamond particles or particles of cubic boron nitride. For both diamonds and cubic boron nitride, the abrasive particles may have an average particle size in the range zium - 181 [tm. In Manga realistic embodiments, the abrasive particles may have a size in the range of 46 μm - 91 μm. In embodiments of the invention, the abrasive particles may have a coating of copper or nickel.

Uppfinningen avser aven ett forfarande att tillverka det uppfmningsenliga slipverktyget. Forfarandet innefattar sintring av abrasiva partiklar tillsammans med metallpulver sâ att sintringen resulterar i en grundmassa i vilken de abrasiva partiklama är inbaddade. Grundmassan kommer darigenom att innefatta ett metalliskt bindemedel. Metallpulvret innefattar koppar och tenn sâ att det metalliska bindemedlet kommer att bli en sintrad bronslegering. Enligt uppfinningen tillsatts kiselnitrid i form av ett pulver till metallpulvret fore sintring och i en sadan utstrackning att kiselnitriden kommer att utgora 0.02 — 0.5 volym-% av det metalliska bindemedlet och foretradesvis 0.1 — 5.0 volym-% av det metalliska bindemedlet. The invention also relates to a method of manufacturing the grinding tool according to the invention. The process comprises sintering abrasive particles together with metal powder so that the sintering results in a matrix in which the abrasive particles are embedded. The matrix will thereby comprise a metallic binder. The metal powder comprises copper and tin so that the metallic binder will become a sintered bronze alloy. According to the invention, silicon nitride in the form of a powder is added to the metal powder for sintering and to such an extent that the silicon nitride will constitute 0.02 - 0.5% by volume of the metallic binder and preferably 0.1 - 5.0% by volume of the metallic binder.

I utforingsformer av det uppfinningsenliga forfarandet kan metallpulvret ytterligare innefatta silver. In embodiments of the process of the invention, the metal powder may further comprise silver.

Nar det har hanvisas till de relativa andelarna av kiselnitrid i det metalliska bindemedlet skall det forstas att clamed avses de volymandelar av pulvret som anvands i sjalva framstallningsprocessen. Med andra ord är tillverkningsforfarandet sadant att, i det pulver som adderas fore sintring, sà utgor kiselnitriden 0.02 — 5.0 volym-% av det metalliska bindemedlet (kiselnitriden raknas som en del av det metalliska bindemedlet). Det antas att kiselnitridpartiklarna kommer att behalla samma relativa volymandel aven efter sintring. When referring to the relative proportions of silicon nitride in the metallic binder, it is to be understood that clamed refers to the volume proportions of the powder used in the manufacturing process itself. In other words, the manufacturing process is such that, in the powder added for sintering, the silicon nitride constitutes 0.02 - 5.0% by volume of the metallic binder (the silicon nitride is shaved off as part of the metallic binder). It is assumed that the silicon nitride particles will retain the same relative volume fraction even after sintering.

En polymer kan valfritt tillsattas till metallpulvret fore sintring, foretradesvis i form av pulver av polyimid sà att aven ett polymert bindemedel bildas som utgor en del av grundmassan. A polymer may optionally be added to the metal powder for sintering, preferably in the form of a polyimide powder so that a polymeric binder is also formed which forms part of the matrix.

Forfarandet kan genomforas pa ett sadant satt att pulvermaterialet for grundmassans bindemedel blandas med de abrasiva partiklarna sâ att en blandning bildas. Blandningen kompakteras sedan i en kallpress. Den kompakterade blandningen hardas sedan i en ugn vid en temperatur i intervallet 380°C - 5°C, foretradesvis 400°C - 500°C under en period av 120 — 150 minuter. Darefter placeras den kompakterade och hardade blandningen i en press och utsatts for ett tryck pa. 1500 — 2000 kg/cm2. Trycket uppratthalls sedan till dess att blandningen har daft en temperatur som är under 300°C. The process can be carried out in such a way that the powder material for the matrix binder is mixed with the abrasive particles so that a mixture is formed. The mixture is then compacted in a cold press. The compacted mixture is then cured in an oven at a temperature in the range of 380 ° C - 5 ° C, preferably 400 ° C - 500 ° C for a period of 120-150 minutes. The compacted and hardened mixture is then placed in a press and subjected to a pressure on. 1500 - 2000 kg / cm2. The pressure is then maintained until the mixture has a temperature below 300 ° C.

Fyllmaterial kan valfritt tillsattas till blandningen av metallpulver och abrasiva partiklar fore sintringsoperationen. Fyllmaterialet kan valfritt innefatta grafit. Filling material can optionally be added to the mixture of metal powder and abrasive particles before the sintering operation. The filler material may optionally include graphite.

Grundmassan air det uppfinningsenliga slipverktyget kan med fordel vara en grundmassa som är en hybrid, d.v.s. en grundmassa som har bade ett metalliskt bindemedel och ett polymert bindemedel. Losningar med hybridbindningar kan kombinera de basta egenskaperna hos metalliska bindemedel med de basta egenskaperna hos polymera bindemedel. Om omskarpning av ett skarpningsverktyg behover goras kan eft slipverktyg med en hybrid-grundmassa omskarpas lattare an en ren metallgrundmassa. Samtidigt har ett slipverktyg med en hybrid-grundmassa en battre notningsbestandighet an en grundmassa som enbart anvander ett polymert bindemedel. The matrix of the abrasive tool according to the invention can advantageously be a matrix which is a hybrid, i.e. a matrix having both a metallic binder and a polymeric binder. Solutions with hybrid bonds can combine the best properties of metallic binders with the best properties of polymeric binders. If sharpening of a sharpening tool needs to be done, after grinding tools with a hybrid matrix can be sharpened more easily than a pure metal matrix. At the same time, a grinding tool with a hybrid matrix has a better groove resistance than a matrix which only uses a polymeric binder.

KORT BESKRIVNING AV FIGURERNA Figur 1 är en schematisk atergivning av ett slipverktyg. BRIEF DESCRIPTION OF THE FIGURES Figure 1 is a schematic representation of a grinding tool.

Figur 2 är en schematisk atergivning i tvarsnitt av abrasiva partiklar inbaddade i ett slipverktygs abrasiva kant. 6 Figur 3 är en schematisk kergivning i tvarsnitt av ett slipverktyg som verkar pa ett arbetsstycke. Figure 2 is a schematic cross-sectional view of abrasive particles embedded in the abrasive edge of a grinding tool. Figure 3 is a schematic cross-sectional view of a grinding tool acting on a workpiece.

Figur 4 är ett diagram som kerger effektforbrukningen ffir tva olika slipverktyg. Figur 5 är en schematisk kergivning i tvarsnitt av en forsta utforingsform av det uppfinningsenliga slipverktyget. Figure 4 is a diagram plotting power consumption for two different grinding tools. Figure 5 is a schematic cross-sectional view of a first embodiment of the grinding tool according to the invention.

Figur 6 är en schematisk atergivning i tvarsnitt av en andra utforingsform av det uppfinningsenliga slipverktyget. Figure 6 is a schematic cross-sectional view of a second embodiment of the grinding tool according to the invention.

Figur 7 är ett diagram som visar notning av ett slipverktyg som en funktion av halten av kis elnitrid. 10 Figur 8 är ett diagram som visar G-talet for ett slipverktyg som en funktion av halten av kis elnitrid. Figure 7 is a diagram showing notching of a grinding tool as a function of the content of silicon nitride. Figure 8 is a diagram showing the G-number of a grinding tool as a function of the content of silicon nitride.

DETALJERAD BESKR1VNING AV UPPFINNINGEN Med hanvisning till Figur 1 visas ett slipverktyg 1. Slipverktyget kan i synnerhet vara en slipskiva som är avsedd fOr bearbetning av harda och/eller sproda material sasom volframkarbid. Sadana material kan finnas i arbetsstycken for Adana verktyg som till exempel borrar eller frdsverktyg och slipverktyget 1 enligt den foreliggande uppfinningen kan vara en slipskiva som anvands for att forma sa.dana verktyg. Slipverktyget 1 innefattar en karna 2 och en abrasiv kant 4. Kaman 2 kan vara gjord av ett mindre dyrt material sasom stal eller nagon annan metall. Alternativt skulle karnan kunna vara gjord av, till exempel, ett polymermaterial. Kaman skulle alien kunna innefatta mer an ett material. Den kan till exempel vara gjord delvis av metall sasom stal eller aluminium och delvis vara av ett polymermaterial. Karnan 2 kan vara forsedd med ett genomgdende hal eller kavitet 3 sâ att slipverktyget 1 kan monteras pa en spindel (ej visad) for roterande rorelse. Med hanvisning till Figur 2 innefattar den abrasiva kanten 4 abrasiva partiklar 5 som är inbaddade i en grundmassa 6. Grundmassan 6 innehaller i sin tur ett metalliskt bindemedel som är en sintrad bronslegering. Det metalliska bindemedlet utgor 50 — 100 volym-% av grundmassan 6 och utforingsformer är saledes tankbara i vilka hela grundmassan 6 utgors av det metalliska bindemedlet. Normalt innefattar emellertid grundmassan 6 kminstone nagon annan bestandsdel. Till exempel kan den innefatta fyllmaterial sasom grafit som har smorjande egenskaper. I de fiesta utforingsformer skulle grundmassan 6 aven innefatta ett polymert bindemedel som kan utgoras av polyimid. 35 Om grundmassan 6 hailer de abrasiva partiklarna 5 vdlkommer de abrasiva partiklarna 5 att avge sma fragment och notas ned gradvis. Som en foljd ddrav kommer notningen pa den abrasiva kanten 4 att bli jamforelsevis langsam sâ att diametem pa slipverktyget 7 1 kan hallas vasentligen konstant under en ldngre tid. Vidare kommer notning pa den abrasiva kanten 4 att hallas i en jamn takt och effekten under drift kommer inte at variera sa mycket. DETAILED DESCRIPTION OF THE INVENTION Referring to Figure 1, there is shown a grinding tool 1. The grinding tool may in particular be a grinding wheel intended for machining hard and / or sprayed materials such as tungsten carbide. Such materials may be present in workpieces for Adana tools such as drills or tooling tools and the grinding tool 1 according to the present invention may be a grinding wheel used to form such tools. The grinding tool 1 comprises a core 2 and an abrasive edge 4. The cam 2 may be made of a less expensive material such as steel or some other metal. Alternatively, the core could be made of, for example, a polymeric material. Kaman alien could include more than one material. It can, for example, be made partly of metal such as steel or aluminum and partly of a polymeric material. The core 2 can be provided with a continuous hall or cavity 3 so that the grinding tool 1 can be mounted on a spindle (not shown) for rotary movement. Referring to Figure 2, the abrasive edge 4 comprises abrasive particles 5 embedded in a matrix 6. The matrix 6 in turn contains a metallic binder which is a sintered bronze alloy. The metallic binder constitutes 50 - 100% by volume of the matrix 6 and embodiments are thus conceivable in which the entire matrix 6 consists of the metallic binder. Normally, however, the matrix 6 comprises at least one other component. For example, it may include fillers such as graphite which have lubricating properties. In most embodiments, the matrix 6 would also comprise a polymeric binder which may be polyimide. If the matrix 6 heals the abrasive particles 5, the abrasive particles 5 will emit small fragments and will gradually wear down. As a consequence, the groove on the abrasive edge 4 will become comparatively slow so that the diameter of the grinding tool 71 can be kept substantially constant for a longer time. Furthermore, grouting on the abrasive edge 4 will be kept at a steady pace and the effect during operation will not vary so much.

Om grundmassan 6 istallet är oformogen att halla de abrasiva partiklarna stadigt kan det handa att abrasiva partiklar lossnar langt innan de fragmenterats. Som en fetid av detta kommer de att ga forlorade innan deras hela slipande potential har utnyttjats. Slipverktyget 1 kommer att notas ut snabbare och diametern pa slipverktyget (sasom en slipskiva) kommer att minska snabbare. En mindre diameter pa slipverktyget 1 kan 10 resultera i en mindre noggrann bearbetning av arbetsstyckena. If the matrix 6 is instead incapable of holding the abrasive particles firmly, abrasive particles may loosen long before they have fragmented. As a fetish of this, they will give up before their full abrasive potential has been exploited. The grinding tool 1 will wear out faster and the diameter of the grinding tool (such as a grinding wheel) will decrease faster. A smaller diameter of the grinding tool 1 can result in a less accurate machining of the workpieces.

Det hanvisas nu till Figur 3. Eft slipverktyg 1 verkar pa ett arbetsstycke 7. Arbetsstycket 7 kan vara, till exempel, ett arbetsstycke som skall formas till ett borr. Slipverktyget 1 roteras med hjdlp av en kraftkalla som verkar genom till exempel en spindel (ej visad). Reference is now made to Figure 3. After grinding tool 1 acts on a workpiece 7. The workpiece 7 may be, for example, a workpiece to be formed into a drill. The grinding tool 1 is rotated by means of a power source which acts through, for example, a spindle (not shown).

Ddrigenom verkar den abrasiva kanten 4 pa arbetsstycket 7 for att skdra ett spar i arbetsstycket. I Figur 3 har arbetsstycket en karndiameter CD som bestams genom verkan av slipverktyget 1. Om slipverktyget 1 nots ned sâ att dess diameter minskar, dâ kommer karndiametern CD att vaxa savida man inte kompenserar fOr nOtningen (till exempel genom ompositionering av slipverktyget 1 i forhallande till arbetsstycket 7). Thereby the abrasive edge 4 of the workpiece 7 acts to cut a groove in the workpiece. In Figure 3, the workpiece has a core diameter CD which is determined by the action of the grinding tool 1. If the grinding tool 1 is lowered so that its diameter decreases, then the core diameter CD will wax unless compensated for the wear (for example by repositioning the grinding tool 1 in relation to workpiece 7).

Det är darfor mycket onskvart att notningen kan hallas lag och att den notning som ager rum inte kommer i plOtsliga oforutsdgbara sprang. It is therefore very unfortunate that the note can be kept lawful and that the note that takes place does not come in sudden unpredictable leaps.

Det kan tillaggas att ndr de abrasiva partiklarna 5 fragmenteras korrekt bit for bit sâ är detta bra fOr slipverktygets 1 friskdrande egenskaper, d.v.s. slipverktygets fOrmaga att om-skarpa sig sjdlvt. Ndr de abrasiva partiklarna 5 fragmenteras bit for bit kan notningen pa grundmassan 6 forlopa mjukt och ytan pa den abrasiva kanten 4 sans inte igen lika ldtt. Om i stallet abrasiva partiklar plotsligt slits bort innan de har fragmenterats ordentligt, da tenderar detta att leda till okad igensattning av ytan, ytan pa den abrasiva kanten 4 kan bli igensatt i hogre grad av sma partiklar 5 fran arbetsstycket 7. Detta kan g6ra det nodvandigt att tillfälligt ta slipverktyget 1 ur drift sa att slipverktyget 1 kan om-skarpas. Om de abrasiva partiklarna 5 fragmenteras gradvis är risken for sadan igensattning mindre. Nar abrasiva partiklar har blivit helt utslitna kan nya abrasiva partiklar 5 komma till ytan i en mjukare process som i sig bidrar till omskarpning av slipverktyget (eller snarare slipverktygets 1 abrasiva kant 4). It can be added that when the abrasive particles 5 are fragmented correctly piece by piece, this is good for the abrasive properties of the grinding tool 1, i.e. The ability of the grinding tool to sharpen itself. When the abrasive particles 5 are fragmented bit by bit, the notch on the matrix 6 can run smoothly and the surface of the abrasive edge 4 does not feel as light again. If instead abrasive particles are suddenly worn away before they have been properly fragmented, then this tends to lead to increased clogging of the surface, the surface of the abrasive edge 4 may be clogged to a greater extent by small particles 5 from the workpiece 7. This may necessitate to temporarily take the grinding tool 1 out of operation so that the grinding tool 1 can be sharpened. If the abrasive particles are gradually fragmented, the risk of such clogging is less. When abrasive particles have become completely worn out, new abrasive particles 5 can come to the surface in a softer process which in itself contributes to sharpening of the grinding tool (or rather the abrasive edge 4 of the grinding tool 1).

Nar abrasiva partiklar slits bort fran den abrasiva kanten innan de har fragmenterats fullstandigt, da tenderar detta att visa sig i slipverktygets effektforbrukning; effekten 8 faller plotsligt och borjar sedan stiga igen efter en stund. Om de abrasiva partiklarna halls ordentligt av grundmassan sâ att de tillats att fragmentera som de skall, da kan awn detta ses pa effektforbrukningen. I ett sadant fall tenderar effekten att ffirbli konstant over tiden (det skall emellertid noteras att det normalt alltid är en viss gradvis stegring i effektbehovet fran de forsta arbetsstyckena sa att det kravs en lagre effekt for de allra forsta arbetsstyckena). When abrasive particles are worn away from the abrasive edge before they have been completely fragmented, this tends to show up in the power consumption of the grinding tool; the effect 8 falls suddenly and then starts to rise again after a while. If the abrasive particles are properly held by the matrix so that they are allowed to fragment as they should, then this can be seen in the power consumption. In such a case, the power tends to remain constant over time (it should be noted, however, that there is normally always a certain gradual increase in the power requirement from the first workpieces so that a lower power is required for the very first workpieces).

Det har foreslagits i en artikel av E. D. Kizikov och P. Kebko ("Microadditions to alloys of the system Cu-Sn-Ti", Institute of Superhard Materials, Academy of Science of the Ukrainian SSR, Kiev, i oversattning fran Metallovedenie I Termicheskaya Obrabotka Metallov, No. 1, sidoma 50 — 53, januari 1987) att en legering av Cu/Sn/Ti som anvands som bindemedel for diamant-slipverktyg forstarks med 0.01 % kiselnitrid (Si3N4). Enligt forfattarna till den artikeln resulterade tillsatsen i hojd strackgrans. It has been suggested in an article by ED Kizikov and P. Kebko ("Microadditions to alloys of the system Cu-Sn-Ti", Institute of Superhard Materials, Academy of Science of the Ukrainian SSR, Kiev, translated by Metallovedenie I Termicheskaya Obrabotka Metallov, No. 1, pages 50 - 53, January 1987) that an alloy of Cu / Sn / Ti used as a binder for diamond grinding tools is reinforced with 0.01% silicon nitride (Si3N4). According to the authors of that article, the addition resulted in a high stretch.

Uppfinnama till den ffireliggande uppfinningen har overvagt vilka &Order som kan vidtas for att forbattra grundmassans formaga att halla de abrasiva partiklarna. Utan att vilja binda sig vid nagon teori tror uppfinnarna att en anledning till att metalliska bindemedel slapper abrasiva partiklar som är inbaddade dari kan vara att dislokationer inuti det metalliska bindemedlet forsvagar det metalliska bindemedlet. Under antagande att denna teori är korrekt tankte sig uppfinnama forst att det borde vara mojligt att forbattra grundmassan genom att forstarka den med partiklar som blockerar dislokationer i det metalliska bindemedlet. Uppfinnarna provade darfor olika tillsatser till det metallpulver som anvandes for sintring av det metalliska bindemedlet. En tillsats som provades var aluminiumoxid som tillsattes i en mangd motsvarande 1.0 volym-% av det metalliska bindemedlet. Detta ledde till en viss forbattring men forbattringen var inte sa bra som uppfinnama hade hoppats. Uppfinnama forsokte aven med tillsats av 0.01 volym-% kiselnitrid. Forbattringen genom den tillsatsen var annu mindre an den forbattring som uppnaddes genom aluminiumoxid. The inventors of the present invention have overseen what orders can be taken to improve the matrix's ability to hold the abrasive particles. Without wishing to be bound by any theory, the inventors believe that one reason why metallic adhesives release abrasive particles embedded therein may be that dislocations within the metallic adhesive weaken the metallic adhesive. Assuming that this theory is correct, the inventors first thought that it should be possible to improve the matrix by reinforcing it with particles that block dislocations in the metallic binder. The inventors therefore tested various additives to the metal powder used for sintering the metallic binder. One additive tested was alumina which was added in an amount corresponding to 1.0% by volume of the metallic binder. This led to some improvement but the improvement was not as good as the inventors had hoped. The inventors also experimented with the addition of 0.01% by volume of silicon nitride. The improvement through that addition was even less than the improvement achieved by alumina.

Uppfinnama undersokte darefter om okade mangder av kiselnitrid skulle leda till Nitre resultat. Detta bekraftades genom fors& som utfordes av uppfinnama. Nar kiselnitrid tillsattes i mangder som var vasentligt sffirre an 0.01 volym-% av det metalliska bindemedlet upptacktes det aft man fick en mycket pkaglig forbattring. The inventors then investigated whether increased amounts of silicon nitride would lead to Nitre results. This was confirmed by rapids challenged by the inventors. When silicon nitride was added in amounts substantially greater than 0.01% by volume of the metallic binder, it was discovered that a very noticeable improvement was obtained.

Till exempel testade uppfinnarna en sammansattning i vilken det metalliska bindemedlet inneholl 0.1 volym-% kiselnitrid (Si3N4). Eft slipverktyg med denna sammansattning jamfordes sedan med ett standardslipverktyg som anvanda en hybrid- 9 grundmassa och som inte inneholl kiselnitrid (Si3N4). Slipverktygen var bada slipverktyg i vilka den abrasiva kanten 4 var utformad som en ring som omgav karnan 2. Under jamforbara forhallanden nottes standardverktygets diameter ned 136pm medan diametern pa slipverktyget med den experimentella sammansattningen bara nottes ned med 58pm. G-talet for verktyget med 1.0 % kiselnitrid var 2335. Som jamforelse nottes ett verktyg med 0.01 volym-% kiselnitrid ned 94 pm medan ett verktyg som anvande 1.0 volym-% aluminiumoxid nottes ned 84 pm. For example, the inventors tested a composition in which the metallic binder contained 0.1% by volume of silicon nitride (Si 3 N 4). Eft grinding tools with this composition were then compared with a standard grinding tool which used a hybrid matrix and which did not contain silicon nitride (Si3N4). The grinding tools were both grinding tools in which the abrasive edge 4 was designed as a ring surrounding the core 2. Under comparable conditions, the diameter of the standard tool was reduced to 136 pm while the diameter of the grinding tool with the experimental composition was reduced to only 58 pm. The G-number of the tool with 1.0% silicon nitride was 2335. For comparison, a tool with 0.01 volume% silicon nitride was down 94 pm while a tool using 1.0% by volume alumina was down 84 pm.

Ett test gjordes med en sammansattning dar kiselnitrid utgjorde 5 volym-% av det metalliska bindemedlet. Notningsbestandigheten var fortfarande god men inte riktigt sà god som for verktyget med 1.0 volym-% kiselnitrid. Verktyget med 5.0 % kiselnitrid hade dessutom hogre effektforbrukning G-talet var gott men inte riktigt sâ gott som for verktygen med 1.0 och 0.1 volym-%. A test was performed with a composition in which silicon nitride constituted 5% by volume of the metallic binder. The wear resistance was still good but not quite as good as for the tool with 1.0% by volume of silicon nitride. The tool with 5.0% silicon nitride also had higher power consumption. The G-ratio was good but not quite as good as for the tools with 1.0 and 0.1% by volume.

Uppfinnama har alien testat en slipskiva som hade en form och sammansattning som liknade de ovriga verktygen som testades men i vilken kiselnitriden utgjorde 0.1 volym% av det metalliska bindemedlet. Det visade sig att, under samma testforhallanden som de andra verktygen som testades blev nOtningen pa verktyget med 0.1 volym-% kiselnitrid 62 pm och G-talet var 2084. Aven om det var underlagset i forhallande till de resultat som uppdaddes vid 1 volym-% sâ var det fortfarande en mycket pataglig forbattring jamfOrt med standard-slipverktyget. The inventors have alien tested a grinding wheel which had a shape and composition similar to the other tools tested but in which the silicon nitride constituted 0.1% by volume of the metallic binder. It turned out that, under the same test conditions as the other tools tested, the wear on the tool with 0.1% by volume of silicon nitride was 62 .mu.m and the G number was 2084. Although it was the basis in relation to the results which were added at 1% by volume so it was still a very patag improvement compared to the standard grinding tool.

Uppfinnarna har aven testat en slipskiva som hade en halt av kiselnitrid pa 0.02 volym% av det metalliska bindemedlet men som i ovrigt var som de andra slipskivoma som testades. Under likvardiga testforhallanden sà hade slipskivan med 0.02 volym-% kiselnitrid en notning (diameterminskning) pa 58 tm och ett G-tal pa 2283. Resultaten var alltsa nagot battre an de resultat som erholls vid ett fOrhallande pa 0.1 volym-%. The inventors have also tested a grinding wheel which had a silicon nitride content of 0.02% by volume of the metallic binder but which was otherwise like the other grinding wheels tested. Under equivalent test conditions, the grinding wheel with 0.02% by volume of silicon nitride had a groove (diameter reduction) of 58 tm and a G-number of 2283. The results were thus somewhat better than the results obtained at a ratio of 0.1% by volume.

Resultaten ledde fram till den slutsatsen att vasentligt battre resultat erhalls i intervallet 0.02 — 5.0 volym-% kiselnitrid (Si3N4). I detta intervall har det visat sig att bade G-tal och notningsbestandighet är vasentligt battre an vid 0 % eller 0.01 %. The results led to the conclusion that significantly better results were obtained in the range 0.02 - 5.0% by volume of silicon nitride (Si3N4). In this range, it has been shown that both G-ratio and note resistance are significantly better at 0% or 0.01%.

Test av notningsbestandighet och G-tal har ocksa utforts vid 0 volym-%, 0.01 volym-%, 0.02 volym-%, 1.0 volym-% och 5.0 volym-% kiselnitrid. Testing of note resistance and G-number has also been performed at 0% by volume, 0.01% by volume, 0.02% by volume, 1.0% by volume and 5.0% by volume of silicon nitride.

De verktyg som testades var slipskivor av vasentligen samma typ som visas i Figur 5, d.v.s. slipskivor med en abrasiv kant som omger en karna 1 och dar slipverktyget 1 10 roterar kring en axel A under drift. Notningsbestandigheten som funktion av halten kiselnitrid kan ses i Figur 7. Notningsbestandigheten uttrycks i Figur 7 som diameterminskning. Som man kan se i Figur 7 'Rade notningsbestandigheten vasentligt nar halten av kiselnitrid okade fran 0.01 % till 0.02 %. Notningsbestandigheten fortsatte att vara hog upp till en halt av kiselnitrid pa 5 volym-% av det metalliska bindemedlet. The tools tested were grinding wheels of essentially the same type as shown in Figure 5, i.e. grinding wheels with an abrasive edge surrounding a core 1 and where the grinding tool 1 rotates about an axis A during operation. The notch resistance as a function of the silicon nitride content can be seen in Figure 7. The notch resistance is expressed in Figure 7 as a reduction in diameter. As can be seen in Figure 7, the note resistance significantly decreased when the silicon nitride content increased from 0.01% to 0.02%. The wear resistance continued to be high up to a content of silicon nitride of 5% by volume of the metallic binder.

Vid 5.0 volym-% kiselnitrid var emellertid notningsbestandigheten nagot lagre jamfort med den bestandighet som observerats vid en halt av 0.02 % - 1.0 %. Uppfinnarna har darfor dragit slutsatsen att den basta notningsbestandigheten erhalls i intervallet 0.02 - 5.0 volym-%. At 5.0% v / v silicon nitride, however, the notch resistance was slightly lower compared to the resistance observed at a content of 0.02% - 1.0%. The inventors have therefore concluded that the best note resistance is obtained in the range 0.02 - 5.0% by volume.

G-talet som funktion av halten av kiselnitrid kan ses i Figur 8. Som man kan se i figuren erhalles de basta vardena vid en halt av kiselnitrid i intervallet 0.02 % - 5.0 %. I Figur 8 syns alien att G-talet sjunker mot hoger i figuren aven om G-talet vid 5.0 volym-% fortfarande är gott. The G-number as a function of the content of silicon nitride can be seen in Figure 8. As can be seen in the figure, the best values are obtained at a content of silicon nitride in the range 0.02% - 5.0%. In Figure 8, the alien shows that the G-number decreases towards higher in the figure, even though the G-number at 5.0 volume% is still good.

Uppfinnarna har darfor dragit den slutsatsen att det metalliska bindemedlet kan innehalla kiselnitrid i en mangd som utgor 0.02 - 5.0 volym-% av det metalliska bindemedlet. Eftersom effektforbrukningen var hOgre vid 5.0 volym-% har uppfinnarna dragit slutsatsen att varden under 5.0 % kommer att ha god notningsbestandighet men lagre effektforbrukning jamfort med verktyg som har en halt av kiselnitrid pa 5 volym- %. Ett fOredraget intervall kan darfor vara 0.02 volym-% till 3.0 volym-%, 0.5 - 3.0 volym-%, 0.5 - 2.0 volym-% eller 1.0 - 2.0 volym-% av det metalliska bindemedlet. The inventors have therefore concluded that the metallic binder may contain silicon nitride in an amount of 0.02 to 5.0% by volume of the metallic binder. Since the power consumption was higher at 5.0% by volume, the inventors have concluded that the value below 5.0% will have good wear resistance but lower power consumption compared with tools that have a silicon nitride content of 5% by volume. A preferred range can therefore be 0.02% by volume to 3.0% by volume, 0.5 - 3.0% by volume, 0.5 - 2.0% by volume or 1.0 - 2.0% by volume of the metallic binder.

Vid 0.1 volym-% var effektforbrukningen i allmanhet lagre an vid 0.02 volym-%. Vid 5.0 volym-% kiselnitrid var effektforbrukningen hogre an vid en halt pa 0.02 % men effektforbrukningen vid 5.0 volym-% var jamnare, effektforbrukningen var mer forutsagbar an vid 0.02 volym-%. At 0.1% by volume, power consumption was generally lower at 0.02% by volume. At 5.0% by volume of silicon nitride, the power consumption was higher at a content of 0.02%, but the power consumption at 5.0% by volume was smoother, the power consumption was more predictable than at 0.02% by volume.

Kiselnitridpartiklarna skall foretradesvis ha en storlek upp till 10 pm (1250 Tyler Mesh). For sallade partiklar kommer detta normalt att betyda att den genomsnittliga kornstorleken är mindre an 10 pm. Den genomsnittliga komstorleken (D50) pa kiselnitridpartiklarna kan da vara kring 2pm - 3pm (beroende pa hur genomsnittlig partikelstorlek mats). Den specifika ytan for kiselnitridpartiklarna kan fordelaktigt ligga i intervallet 5 m2/g - 6 m2/g. Om de partiklar som anvands är for sma kan detta leda till igensattning samt problem under tillverkningen. For att man skall ge det metalliska bindemedlet optimal styrka tror uppfinnarna vidare att man foretradesvis skall inkludera partiklar upp till 10 pm. 11 Normalt skall grundmassan 6 vidare innefatta ett polymert bindemedel som har sintrats tillsammans med det metalliska bindemedlet sâ att det polymera bindemedlet och det metalliska bindemedlet bildar ett sammanfogat natverk (Wen om ett sadant polymert bindemedel är valfritt). Anvandningen av ett polymert bindemedel gör det mojligt att finjustera grundmassans egenskaper och anpassa den till olika typer av abrasiva partiklar. Det polymera bindemedlet kan lampligen vara polyimid eller innefatta polyimid. Anledningen till detta är att polyimid är varmebestandigt och kan tala de hoga temperaturema under sintring. Om ett polymert bindemedel anvands kan det polymera bindemedlet vara narvarande i en mangd av upp till 50 volym-% av grundmassan (d.v.s. mangden polymert bindemedel ligger i intervallet 0 — 50 volym-% av grundmassan). Till exempel kan det polymera bindemedlet motsvara 10 — 40 volym-% eller 10 -30 volym-% av grundmassan. The silicon nitride particles should preferably be up to 10 microns in size (1250 Tyler Mesh). For salted particles, this will normally mean that the average grain size is less than 10 microns. The average grain size (D50) of the silicon nitride particles can then be around 2pm - 3pm (depending on how the average particle size is fed). The specific surface area of the silicon nitride particles can advantageously be in the range 5 m2 / g - 6 m2 / g. If the particles used are too small, this can lead to clogging and problems during manufacture. In order to give the metallic binder optimum strength, the inventors further believe that particles up to 10 μm should preferably be included. Normally, the matrix 6 should further comprise a polymeric binder which has been sintered together with the metallic binder so that the polymeric binder and the metallic binder form a joined network (Wen if such a polymeric binder is optional). The use of a polymeric binder makes it possible to fine-tune the properties of the matrix and adapt it to different types of abrasive particles. The polymeric binder may suitably be polyimide or comprise polyimide. The reason for this is that polyimide is heat resistant and can withstand the high temperatures during sintering. If a polymeric binder is used, the polymeric binder may be present in an amount of up to 50% by volume of the matrix (i.e. the amount of polymeric binder is in the range of 0-50% by volume of the matrix). For example, the polymeric binder may correspond to 10 to 40% by volume or 10 to 30% by volume of the matrix.

Det polymera bindemedlet skulle mojligen kunna utgoras av nagot annat polymermaterial. Det skulle till exempel kunna utgOras av polyamidimid som Wen det är i stand att tala hoga temperaturer. Emellertid foredras polyimid eftersom det har battre slipegenskaper an polyamidimid. The polymeric binder could possibly be made of some other polymeric material. It could, for example, be made of polyamidimide such as Wen it is able to speak high temperatures. However, polyimide is preferred because it has better abrasive properties than polyamidimide.

Det metalliska bindemedlet är foretradesvis en bronslegering som innefattar koppar, tenn och silver. Silver forbattrar de onskvarda egenskaperna hos det metalliska bindemedlet. The metallic binder is preferably a bronze alloy comprising copper, tin and silver. Silver improves the adverse properties of the metallic binder.

De abrasiva partiklama 5 kan vara antingen diamantpartiklar eller partiklar av kubisk bomitrid. Diamanter är hardare och har battre abrasiva egenskaper men kubisk bomitrid är mer temperaturbestandigt. Dessutom kan diamanter reagera kemiskt med vissa material. The abrasive particles 5 can be either diamond particles or particles of cubic bomitride. Diamonds are harder and have better abrasive properties, but cubic bomitride is more temperature resistant. In addition, diamonds can react chemically with certain materials.

De abrasiva partiklama 5 kan vara är diamantpartiklar eller partiklar av kubisk bomitrid. Partiklarna kan ligga i intervallet 411m - 181[tm aven om partiklar utanfor detta intervall kan overvagas beroende pa de krav som stalls i vaije specifikt fall. I manga realistiska utforingsformer kan de abrasiva partiklama 5 ha en genomsnittlig partikelstorlek i intervallet 46[1m — 91 lam vilket är ett intervall som är lampligt for manga slipningsoperationer. The abrasive particles 5 may be are diamond particles or particles of cubic bomitride. The particles can be in the range 411m - 181 [mu] m, although particles outside this range can be monitored depending on the requirements set in each specific case. In many realistic embodiments, the abrasive particles 5 may have an average particle size in the range of 46 μm - 91 lam, which is a range suitable for many grinding operations.

De abrasiva partiklama kan valfritt ha en belaggning av koppar eller nickel. En belaggning av koppar eller nickel kan forbattra bindningen mellan de abrasiva 12 partiklarna 5 och grundmassan 6. De abrasiva egenskaperna hos partiklarna 5 kommer emellertid att minskas nagot om partiklama har en sadan belaggning. The abrasive particles may optionally have a coating of copper or nickel. A coating of copper or nickel can improve the bond between the abrasive particles 5 and the matrix 6. However, the abrasive properties of the particles 5 will be somewhat reduced if the particles have such a coating.

Den relativa andelen av abrasiva partiklar 5 i forhallande till bindemedlen och fyllmaterialen i grundmassan 6 kan variera beroende pa kraven i varje enskilt fall. I manga realistiska utforingsformer kan mangden abrasiva partiklar motsvara en 10 — 50 % av den totala volymen av den abrasiva kanten (d.v.s. den totala volymen av de abrasiva partiklarna och grundmassan). Om den relativa andelen av abrasiva partiklar Overstiger 50% finns det en vasentlig risk att grundmassan inte langre kommer att kunna 10 Ulla de abrasiva partiklarna. Om den relativa andelen av abrasiva partiklar understiger 10% kan den slipande effekten bli for liten. Den relativa andelen av abrasiva partiklar kan foretradesvis ligga i intervallet 15% - 30% och ett lampligt varde kan vara 25%. The relative proportion of abrasive particles 5 in relation to the binders and fillers in the matrix 6 may vary depending on the requirements in each individual case. In many realistic embodiments, the amount of abrasive particles may correspond to 10 - 50% of the total volume of the abrasive edge (i.e. the total volume of the abrasive particles and the matrix). If the relative proportion of abrasive particles exceeds 50%, there is a significant risk that the matrix will no longer be able to absorb the abrasive particles. If the relative proportion of abrasive particles is less than 10%, the abrasive effect may be too small. The relative proportion of abrasive particles may preferably be in the range of 15% - 30% and a lamp value may be 25%.

Foretradesvis är kiselnitriden narvarande i form av kom som har en genomsnittlig kornstorlek i intervallet 1 lam -10 pm. De kan till exempel ha en genomsnittlig storlek i intervallet lpm - lOpm eller 2pm - 911m. Uppfinnarna tror att kiselnitridpartiklar mindre an 0.1 pm kan leda till hopklumpning av kiselnitridpartiklarna vilket reducerar deras forstarkande effekt. Preferably, the silicon nitride is present in the form of grains having an average grain size in the range of 1 lam -10 μm. For example, they may have an average size in the range lpm - 10pm or 2pm - 911m. The inventors believe that silicon nitride particles smaller than 0.1 μm can lead to clumping of the silicon nitride particles which reduces their reinforcing effect.

Kiselnitridpartiklarna kan ha tre olika kristallografiska strukturer som kallas a-, och y-fas Oven kanda som trigonal fas, hexagonal fas och kubisk fas). De vanligaste är afasen och13-fasen. Det är endast under hogt tryck och hog temperatur som y-fasen kan syntetiseras. Vilken som helst av dessa faser kan anvandas. Foretradesvis anvands afasen. De kiselnitridpartiklar som tillsatts kan Liven vara en blandning av partiklar av olika faser. The silicon nitride particles can have three different crystallographic structures called a-, and y-phase (also known as trigonal phase, hexagonal phase and cubic phase). The most common are the aphase and the 13-phase. It is only under high pressure and high temperature that the y-phase can be synthesized. Any of these phases can be used. Preferably the bevel is used. The silicon nitride particles added can be a mixture of particles of different phases.

Med hanvisning till Figur 4 jamfors ett uppfinningsenligt slipverktyg med ett standardslipverktyg. Den vertikala axeln representerar effektforbrukning medan den horisontella axeln representerar ett antal arbetsstycken pa vilka respektive slipverktyg har verkat. I Figur 5 representerar B5 ett slipverktyg enligt uppfinningen medan EZ representerar ett standardslipverktyg. Som man kan se i Figur 4 har verktyget som representeras som B5 en effektforbrukning som forst stiger brant och darefter forblir vasentligen konstant. Det konventionella verktyget som representeras av EZ har en effektforbrukning som stiger brant och sedan plotsligt faller innan den stiger igen. Detta indikerar att de abrasiva partiklarna i B5-verktyget fragmenteras langsamt medan EZ representerar ett slipverktyg dar de abrasiva partiklama plotsligt slits bort. Notningen pa verktyget kommer darfor att ga snabbare. 13 Det kan tillaggas att B5 representerar ett verktyg med bade ett metalliskt bindemedel och ett polymert bindemedel. Det metalliska bindemedlet är ett brons som har koppar, ten och silver. Det har sintrats med anvandning av ett metallpulver som innehaller volym-% koppar, 45 volym-% tenn och 10 volym-% silver. I verktyget enligt B5 utgor det polymera bindemedlet 1.0 volym-% av den totala mangden bindemedel. Referring to Figure 4, a grinding tool according to the invention is compared with a standard grinding tool. The vertical axis represents power consumption while the horizontal axis represents a number of workpieces on which the respective grinding tools have acted. In Figure 5, B5 represents a grinding tool according to the invention while EZ represents a standard grinding tool. As can be seen in Figure 4, the tool represented as B5 has a power consumption that first rises steeply and then remains essentially constant. The conventional tool represented by EZ has a power consumption that rises sharply and then suddenly falls before rising again. This indicates that the abrasive particles in the B5 tool are slowly fragmented while EZ represents an abrasive tool where the abrasive particles are suddenly worn away. The use of the tool will therefore go faster. It can be added that B5 represents a tool with both a metallic binder and a polymeric binder. The metallic binder is a bronze that has copper, tin and silver. It has been sintered using a metal powder containing by volume% copper, 45% by volume tin and 10% by volume silver. In the tool according to B5, the polymeric binder constitutes 1.0% by volume of the total amount of binder.

Slipverktyget enligt Figur 1 kan ha ett sadant tvarsnitt som visas i Figur 5. I en sadan utforingsform kan den abrasiva kanten 4 vara placerad radiellt utanfor karnan 2 sa att kanten 4 fullstandigt omger karnan 2. De test som forklaras med hanvisning till Figur 4, Figur 7 och Figur 8 har gjorts pa ett sadant slipverktyg. Uppfinningen är emellertid inte begransad till en sadan utforingsform. Med hanvisning till Figur 6 skall det inses att karnan 2 kan stracka sig atminstone lika langt i den radiella riktningen som den abrasiva kanten 4. I Figur 6 har slipverktyget en abrasiv kant 4 som inte stacker sig bortom karnan 2 i den radiella riktningen. I stallet har den abrasiva kanten 4 en utstrackning i den axiella riktningen som skiljer sig frail karnans 2 (den axiella riktningen är rotationsaxeln A for slipverktyget 1 ndr det drivs av en spindel, se Figur 5 och Figur 6). Det skall ocksâ inses att slipverktyget 1 inte nodvandigtvis är utformat fOr rotation. I stallet skulle det kunna verka pa arbetsstycken i en fram- och atergaende rorelse. I patentkravens sammanhang skall ddrfor termen "karna" forstas brett som vilken som helst barkropp air den abrasiva kanten. Pa samma satt skall termen "kant" ocksa forstas brett som vilket som helst lager som är fastat till karnan 2 sa att abrasiva partiklar kan verka pa ett arbetsstycke. The grinding tool according to Figure 1 may have such a cross section as shown in Figure 5. In such an embodiment, the abrasive edge 4 may be located radially outside the core 2 so that the edge 4 completely surrounds the core 2. The tests explained with reference to Figure 4, Figure 7 and Figure 8 have been made on such a grinding tool. However, the invention is not limited to such an embodiment. Referring to Figure 6, it will be appreciated that the core 2 may extend at least as far in the radial direction as the abrasive edge 4. In Figure 6, the grinding tool has an abrasive edge 4 which does not extend beyond the core 2 in the radial direction. Instead, the abrasive edge 4 has an extension in the axial direction which differs from the core 2 (the axial direction is the axis of rotation A of the grinding tool 1 when it is driven by a spindle, see Figure 5 and Figure 6). It should also be understood that the grinding tool 1 is not necessarily designed for rotation. Instead, it could affect workpieces in a reciprocating motion. In the context of the claims, therefore, the term "vessels" is to be understood as broadly as any support body on the abrasive edge. In the same way, the term "edge" should also be understood broadly as any layer attached to the core 2 so that abrasive particles can act on a workpiece.

Uppfinningen innefattar vidare ett forfarande for att framstalla det uppfinningsenliga verktyget. Forfarandet innefattar sintring av abrasiva partiklar tillsammans med metallpulver som innefattar koppar och tenn sâ att sintringen resulterar i en grundmassa i vilken de abrasiva partiklarna 5 är inbaddade. Grundmassan innefattar ett metalliskt bindemedel som är en sintrad bronslegering. Enligt uppfinningen tillsatts kiselnitrid i form av pulver till metallpulvret fore sintring i en sadan mangd att kiselnitriden kommer att utgora 0.1 — 5.0 volym-% av det metalliska bindemedlet. The invention further comprises a method for producing the tool according to the invention. The process comprises sintering abrasive particles together with metal powder comprising copper and tin so that the sintering results in a matrix in which the abrasive particles are embedded. The matrix comprises a metallic binder which is a sintered bronze alloy. According to the invention, silicon nitride in the form of powder is added to the metal powder for sintering in such an amount that the silicon nitride will constitute 0.1 - 5.0% by volume of the metallic binder.

Metallpulvret som anvands är foretradesvis metallpulver med partiklart som är mindre an 44 pm men de skall foretradesvis vara storre an kiselnitridpartiklarna. Foretradesvis skall de vara atminstone dubbelt sâ stora. En genomsnittlig storlek i intervallet 15 pm — 44 pm kan vara 14 Metallpulvret kan valfritt aven innefatta silver. The metal powder used is preferably metal powder with particulate matter smaller than 44 microns, but they should preferably be larger than the silicon nitride particles. Preferably they should be at least twice as large. An average size in the range 15 μm - 44 μm may be 14 The metal powder may optionally also include silver.

Metallpulvret kan komma i form av fOrlegerade partiklar eller som partiklar av ren koppar, rent tenn, rent silver etc. The metal powder can come in the form of pre-alloyed particles or as particles of pure copper, pure tin, pure silver, etc.

En polymer kan tillsattas till metallpulvret fOre sintring, fOretradesvis i form av polyimidpulver sâ att aven ett polymert bindemedel bildas som är en del av grundmassan 6. A polymer can be added to the metal powder before sintering, preferably in the form of polyimide powder so that a polymeric binder is also formed which is part of the matrix 6.

Sintringsforfarandet kan utforas sâ att pulvermaterialet for grundmassans 6 bindemedel blandas med de abrasiva partiklarna 5. Blandningen kompakteras i en kallpress. Den kompakterade blandningen hardas sedan i en ugn vid en temperatur i intervallet 380°C - 520°C, foretradesvis 400°C - 500°C eller 440°C - 460°C under en period av 120 — 150 minuter. Den tid som erfordras beror pa storleken. I en stone pressform kravs mer tid. The sintering process can be carried out so that the powder material for the binder 6 of the matrix is mixed with the abrasive particles 5. The mixture is compacted in a cold press. The compacted mixture is then cured in an oven at a temperature in the range of 380 ° C - 520 ° C, preferably 400 ° C - 500 ° C or 440 ° C - 460 ° C for a period of 120 - 150 minutes. The time required depends on the size. In a stone press form more time is required.

Darefter (foretradesvis omedelbart darefter) placeras den kompakterade och hardade blandningen i en press och utsatts for ett tryck pa 1500 — 2000 kg/cm2. Trycket uppratthalls sedan till dess att blandningen har natt en temperatur som är under 300°C. Then (preferably immediately afterwards) the compacted and hardened mixture is placed in a press and subjected to a pressure of 1500 - 2000 kg / cm 2. The pressure is then maintained until the mixture has a temperature below 300 ° C at night.

Till exempel har uppfinnarna framstallt slipverktyg enligt denna metod i en process dar temperaturen i ugnen var 450°C. For example, the inventors have manufactured grinding tools according to this method in a process where the temperature in the oven was 450 ° C.

Den abrasiva kanten 4 kan aven framstallas genom "spark plasma sintering" (SPS). Genom denna teknik kan den abrasiva kanten 4 framstallas mycket snabbt. The abrasive edge 4 can also be produced by "kick plasma sintering" (SPS). By this technique the abrasive edge 4 can be produced very quickly.

Kanten med grundmassan som innehaller abrasiva partiklar kan sintras separat och darefter fastas (till exempel limmas) till karnan 2. Altemativt kan den abrasiva kanten 5 sintras direkt pa karnan 2 sâ att den binds till karnan samtidigt som den bildas. Fore sintring kan karnan 2 belaggas elektrolytiskt med koppar pa atminstone en yta av karnan som kommer att mota den abrasiva kanten 4. Den abrasiva kanten 4 kan sedan sintras pa den kopparbelagda ytan sâ att en skarv bildas. The edge with the matrix containing abrasive particles can be sintered separately and then fastened (for example glued) to the core 2. Alternatively, the abrasive edge 5 can be sintered directly on the core 2 so that it binds to the core at the same time as it is formed. Before sintering, the core 2 can be electrolytically coated with copper on at least one surface of the core which will meet the abrasive edge 4. The abrasive edge 4 can then be sintered on the copper coated surface so that a joint is formed.

Fyllmaterial kan valfritt tillsattas till blandningen av metallpulver och abrasiva partiklar 5 fore sintringsoperationen. Som fora forklarats kan fyllmaterialet innefatta grafit. Andra mojliga fyllmaterial kan innefatta, till exempel, sfarer av aluminiumoxid. Filling material can optionally be added to the mixture of metal powder and abrasive particles before the sintering operation. As explained in the forums, the filler material may include graphite. Other possible filler materials may include, for example, alumina spheres.

Foretradesvis valjs bronset som anvands i det metalliska bindemedlet fran den grupp som inkluderar koppar — tenn (Cu/Sn), koppar — tenn — kobolt (Cu/Sn/Co), koppar — tenn — nickel (Cu/Sn/Ni) eller koppar — tenn — silver (Cu/Sn/Ag). Annu mer foredraget är bronset ett brons av koppar — term — silver. Andra bronslegeringar kan ocksa overvagas. Preferably, the bronze used in the metallic binder is selected from the group comprising copper - tin (Cu / Sn), copper - tin - cobalt (Cu / Sn / Co), copper - tin - nickel (Cu / Sn / Ni) or copper - tin - silver (Cu / Sn / Ag). Even more preferably, the bronze is a bronze of copper - term - silver. Other bronze alloys can also be monitored.

Det uppfinningsenliga slipverktyget kan anvandas for bearbetning av harda och/eller sproda material. Detta utesluter inte att slipverktyget kan anvandas aven for andra material. The grinding tool according to the invention can be used for processing hard and / or sprayed materials. This does not exclude that the grinding tool can also be used for other materials.

I utforingsformer av uppfinningen kan grundmassan 6 valfritt aven innefatta atminstone en keramisk bestandsdel i form av keramiska partiklar. Den keramiska bestandsdelen kan vara, till exempel, fritta och innehalla Si02. Keramiska partiklar for grundmassan kan utgoras av fritta i form av sfariska partiklar som har en partikelstorlek pa 50 itm — 500[im beroende pa storleken av de abrasiva partiklarna. FOr storre abrasiva partiklar kommer stone keramiska partiklar att anvandas. De abrasiva partiklarna kan vara inbaddade i de keramiska partiklarna medan de keramiska partiklarna är inbaddade i en hybrid-grundmassa med ett metalliskt bindemedel och ett polymert bindemedel. De keramiska partiklarna kan hallas hardare av grundmassan an vad de abrasiva partiklarna skulle hallas. Den abrasiva kantens friskarande egenskaper forbattras darigenom. Den keramiska bestandsdelen har inte lika god nOtningsbestandighet som det metalliska bindemedlet. Genom att kombinera keramiska, metalliska och polymera bindemedel är det mojligt att kombinera dessa bindemedels basta egenskaper. 16 In embodiments of the invention, the matrix 6 may optionally also comprise at least one ceramic component in the form of ceramic particles. The ceramic component may be, for example, free and contain SiO 2. Ceramic particles for the matrix can consist of frit in the form of spherical particles having a particle size of 50 itm - 500 [mu] m depending on the size of the abrasive particles. For larger abrasive particles, stone ceramic particles will be used. The abrasive particles may be embedded in the ceramic particles while the ceramic particles are embedded in a hybrid matrix with a metallic binder and a polymeric binder. The ceramic particles can be held harder by the matrix than what the abrasive particles would hold. The healing properties of the abrasive edge are thereby improved. The ceramic component does not have as good abrasion resistance as the metallic binder. By combining ceramic, metallic and polymeric binders, it is possible to combine the best properties of these binders. 16

Claims (14)

1. l. A grinding tool (l) for machining hard and/or brittle materials whichgrinding tool (1) comprises a core (2) and an abrasive rim (4), the abrasive rim (4)comprising abrasive particles (5) embedded in a matrix (6), the matrix (6) comprising ametallic bonding agent which is a sintered bronze alloy, the metallic bonding agentconstituting 50 % - 100 % by volume of the matrix, the metallic bonding agentcontaining silicon nitride in an amount that constitutes 0.02 % - 5.0 % by volume of themetallic bonding agent characterized in that the silicon nitride is present in the shape ofgrains having an average grain size which is less than 10 um and above Olum.
2. A grinding tool (1) according to claim 1, Wherein the matrix (6) fiirthercomprises a polymeric bonding agent that has been sintered together with the metallicbonding agent such that the polymeric bonding agent and the metallic bonding agentform a connected network.
3. A grinding tool (1) according to claim l or claim 2, Wherein the siliconnitride constitutes 0.3 % - 5.0 % by volume of the metallic bonding agent, preferably0.5 % - 3 % by volume and even more preferred 0.5 % - 2 % by volume.
4. A grinding tool according to claim 2, Wherein the polymeric bondingagent comprises polyimide.
5. A grinding tool according to claim l or claim 2, Wherein the matrixadditionally comprises filler materials such as graphite.
6. A grinding tool according to any of claims l - 5, Wherein the metallicbonding agent is a bronze alloy that comprises copper, tin and silver.
7. A grinding tool according to any of claims l - 6, Wherein the abrasiveparticles (5) are diamond particles or cubic boron nitride particles.
8. A grinding tool according to claim 7, Wherein the abrasive particles (5)have a mean particle size in the range of 4um - 18 1 um and preferably in the range of46um - 9lum.
9. A grinding tool according to claim 8, Wherein the abrasive particles (5) have a coating of copper or nickel.
10. A method of making a grinding tool (1) Which method comprises sinteringabrasive particles together With metallic powder that comprises copper and tin such that the sintering results in a matrix (6) in which the abrasive particles (6) are embedded, thematrix comprising a metallic bonding agent which is a sintered bronze alloy,characterized in that silicon nitride in the form of a powder is added to the metallicpowder before sintering and to such an extent that the silicon nitride will constitute 0.02% - 5.0% by volume of the metallic bonding agent and wherein the silicon nitride whichis added is in the shape of grains having an average grain size which is less than 10|.Lmand above 0.1 um.
11. 1 1. A method according to claim 10, wherein the metallic powder additionallycomprises silver.
12. A method according to claim 10 or claim l 1, wherein a polymer is addedto the metallic powder before sintering, preferably in the form of polyimide powder,such that also a polymeric bonding agent is formed which is a part of the matrix (6).
13. A method according to any of claims 10 - 12, wherein the methodcomprises; mixing the powder material for the bonding agents of the matrix (6) with theabrasive particles (5); compacting the mixture in a cold press; curing the compactedmixture in a kiln at a temperature in the range of 380°C - 520°C, preferably 400°C -500°C, for a period of 120 - 150 minutes; thereafter placing the compacted and curedmixture in a press and subjecting it to a pressure of 1500 - 2000 kg/cm2; and holding the pressure until the mixture has reached a temperature below 300°C.
14. A method according to any of claims 10 - 13, wherein filler material isadded to the mixture of metallic powder and abrasive particles (5) before the sinteringoperation and wherein the filler material comprises graphite.
SE1150720A 2011-07-22 2011-07-22 A grinding tool for machining brittle materials and a process for making a grinding tool SE537723C2 (en)

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SE1150720A SE537723C2 (en) 2011-07-22 2011-07-22 A grinding tool for machining brittle materials and a process for making a grinding tool
JP2014521596A JP5982725B2 (en) 2011-07-22 2012-07-18 Grinding tool for machining brittle materials and method of making a grinding tool
US14/233,932 US20140227952A1 (en) 2011-07-22 2012-07-18 Grinding tool for machining brittle materials and a method of making a grinding tool
PCT/SE2012/050842 WO2013015737A1 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
NZ620302A NZ620302B2 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
EP12817725.0A EP2734334B1 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
MYPI2014000176A MY169695A (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
BR112014001447A BR112014001447A2 (en) 2011-07-22 2012-07-18 grinding tool for machining brittle materials and production method
AU2012287547A AU2012287547B2 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
CN201280036226.6A CN103781596B (en) 2011-07-22 2012-07-18 For processing the grinding tool of fragile material and preparing the method for grinding tool
RU2014106604/02A RU2594923C2 (en) 2011-07-22 2012-07-18 Grinding tool for processing fragile materials and method of its manufacturing
KR1020147004205A KR101861890B1 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
MX2014000837A MX358578B (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool.
CA2842534A CA2842534A1 (en) 2011-07-22 2012-07-18 A grinding tool for machining brittle materials and a method of making a grinding tool
IL230524A IL230524A (en) 2011-07-22 2014-01-19 Grinding tool for machining brittle materials and method of making a grinding tool
ZA2014/00915A ZA201400915B (en) 2011-07-22 2014-02-06 A grinding tool for machining brittle materials and a method of making a grinding tool

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RU2594923C2 (en) 2016-08-20
CA2842534A1 (en) 2013-01-31
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CN103781596A (en) 2014-05-07
WO2013015737A1 (en) 2013-01-31
JP5982725B2 (en) 2016-08-31
IL230524A (en) 2017-10-31
MX358578B (en) 2018-08-27
SE1150720A1 (en) 2013-01-23
BR112014001447A2 (en) 2017-02-21
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EP2734334B1 (en) 2022-11-02
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AU2012287547A1 (en) 2014-03-06
EP2734334A1 (en) 2014-05-28
EP2734334A4 (en) 2015-11-11
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NZ620302A (en) 2015-12-24
AU2012287547B2 (en) 2017-02-02

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