Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B24—GRINDING; POLISHING
  • B24D—TOOLS FOR GRINDING, BUFFING OR SHARPENING
  • B24D3/00—Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
  • 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
  • B24D3/02—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

Definitions

• the invention relates to a grinding tool for machining in particular brittle hard materials such as natural and artificial stone, sintered hard metal, ceramic and the like, wherein the grinding tool in one piece or preferably in several parts a supporting part and a grinding body is constructed and the grinding tool or its grinding wheel made of high-performance abrasive grain such as diamond, metallic binder, synthetic resin binder and optionally filler and wherein the metallic binder and the synthetic resin binder are each one coherent network are sintered, the metal bond network and that Resin bond network a intertwined, coherent, double spatial network permeating each other and the abrasive grain and optionally the filler is within at least one of the different binders and / or in the phase boundary between the different binders.
• high-performance abrasive grain such as diamond, metallic binder, synthetic resin binder and optionally filler
• the metallic binder and the synthetic resin binder are each one coherent network are sintered, the metal bond network and that Resin bond network a intertwined,
• the invention further relates to a method for producing such Grinding wheel.
• Grinding tools of the type mentioned can be in both wet and Dry grinding processes can be used.
• the areas of application are Processing of natural and artificial stone, preferably with multiple parts Grinding tools in e.g. grinding and polishing lines for decorative Stone materials, in the production and repair grinding of tools for metal cutting, made entirely or partially of hardened tool steel, Tungsten carbide or ceramic exist.
• the patent US 3650715 specifies a grinding wheel bond, the dendritic Contains metal as a filler in polyimide resin.
• the metal lies as "clusters of dendritic metal particles ", ie as clusters of dendrites.
• the above Patent suggests highly heat-resistant polyimide resin for use in highly stressed grinding tools, particularly those used in dry grinding in front.
• Silver added is preferred as a filler. This suggests grinding wheels at which the soft engagement of resin-bonded grinding wheels and the Thermal conductivity and stability of metal bonds are sought.
• a metal synthetic resin composite material from the generic grinding tools can be produced is disclosed in US 4,042,347.
• This material is made from a continuous metal matrix and a continuous synthetic resin matrix and is produced by hot pressing a mixture of intermediate products.
• the preliminary products for the metal matrix include an elemental metal with a melting point below 450 ° C and an intermetallic component or alloy with a Melting point above 500 ° C.
• the continuous resin matrix is at Can be processed at temperatures above 250 ° C. in one shown in this document Exemplary embodiments are copper powder and tin powder to a sintered bronze sintered, with remnants of the copper melting only at higher temperatures remain.
• the material disclosed in US 4,042,347 A for manufacturing of grinding tools has the disadvantage that a soft tripologically unfavorable Pure metal is provided as a high-melting component. This in turn has negative effects on the grinding properties of the fabricated from it Grinding tool.
• the object of the invention is to provide an improved grinding wheel, which is under Use of highly heat-resistant synthetic resins and metal alloys as Binding raw materials improve the grinding properties, increase the Machining performance and economic use of the expensive contained High performance abrasive grain enables.
• Another object of the invention is a method specify with which such grinding wheels can be produced.
• the metallic Binder contains a copper-tin-bronze alloy in the non-sintered state.
• the two interlinked binding networks extend over the entire grinding wheel, whereas with such tools according to the prior art Technique of the metal component of the bond as clusters of filler particles in a synthetic resin matrix is present. It was recognized that when the Sinterability of the metallic component and the synthetic resin component Binding to each other a safe education from two to completely different Networks based on substances.
• the sinterability is included characterized by the same sintering temperature during pressure sintering for both Network raw materials. Between the webs or within the webs of any binding network Abrasive grains and possibly filler particles are embedded.
• Training of the two networks during the pressure sintering process can both in the area of the metallic and in the area of the plastic binding part Abrasive grains enclosed and for later contact with the Workpiece to be integrated.
• the presence of the metal bond portion in Form of an extensive metal mesh a very good support effect in the bond structure similar to the hardening effect of reinforcing steel in Concrete.
• the synthetic resin network embedded in between is responsible for compliance and vibration damping when entering Abrasive grains in the brittle hard workpiece surface.
• the sinterability of the metal binding component is increased adapted to that of the respective synthetic resin binding component of the binding. This is done by selecting the alloy composition of the metallic Binding component with regard to pressure softening point and liquid phase formation.
• plastic binder is a high temperature thermoplastic and a corresponding one for the metallic network low-pressure alloy is selected, which is preferably a Bronze with a composition of 60 volume percent copper and 40 volume percent Can be tin.
• the formation of the two inventive intertwined networks are even at the maximum Processing temperatures of the high temperature thermoplastic of 300 ° C reached.
• Another embodiment of the invention is given when the network made of synthetic resin binders made of a cross-hardenable pressure sinterpolymer is built up from the group of polyimides.
• the corresponding metal bond network can also be used in the invention preferably be made of bronze.
• the associated pressure sintering temperature in this embodiment is 400 to 500 ° C, one by a sintered metal bond and build a resin-bound spatial network.
• a further embodiment of the inventive concept is given if in Adaptation to the relatively low processing temperatures for the synthetic resin binding network low sintering alloys are used, which then usually also ductile or lubricating when grinding, as mentioned above, could be.
• the invention has recognized that on the basis of known binders such as High temperature resins and sintered metal alloys make major improvements when building high-performance abrasive materials possible are. The improvements that can be achieved are in the manufacturing process bound. Accordingly, the invention also relates to a method for the production of a grinding wheel with process steps according to the marking of independent claim 7.
• thermoplastic When using a high temperature thermoplastic becomes a common sintering temperature higher than 300 ° C for pressure sintering.
• pressure sinter polymer The common pressure sintering temperature can be selected from the group of polyimides for the formation of a network of metal bonds and from Resin bond can be increased to about 500 ° C. It is essential that the pressure sinterability of the metal bond portion already at one temperature is given, which is at least 10 ° C below the respective degradation temperature of the synthetic resin bond portion.
• the invention takes advantage of the surprising finding that the common Pressing and sintering or the common pressure sintering two binding powders, each completely different in nature, each with one Binding part in the grinding wheel leads. It is only important to introduce the Sintering temperature of the metallic binding component to the processing temperature of the synthetic resin binding component when using a high temperature thermoplastic. When using thermosetting sintered polymer must also have its special processing and curing temperature the basis for the introduction of the sintering temperature of the metallic Be a binding component. Determining the common sintering temperature is the processing temperature of the binding resin at which there is still sufficient distance from the degradation temperature of the resin. This minimum distance was around 10 ° C.
• the Introducing the sinterability of the metallic binding component to that the synthetic resin binding component using a bronze powder modified with tin brought about. It was found that additional tin powder with a grain size of 2 to 50 my the adaptation of the sintering conditions to the requirements of plastic binding processing much easier.
• Binding of the grinding wheel is particularly low, common Processing temperatures from 300 ° C upwards are required to ensure safe To ensure training of the metal bond network. In these cases it has been shown that, as is known per se, bismuth in the presence of copper and tin the sinterability by binding particularly low-melting ones Makes structural components sinterable.
• the grinding fitting for a D11V9 cup wheel was manufactured for dry grinding of milling cutters equipped with P20 carbide on a Strausack tool grinding machine.
• the amount of diamond grain was measured so that a concentration of C75 (3.3 carats per cm 3 ) was produced in the finished abrasive coating.
• the powder resin contained 2% "75F" tin powder from Pometon / France as a flux or to adjust the sinterability of the trainees different binding networks.
• the common pressure sintering took place in the abrasive coating form at 370 ° C. for 20 minutes in a nitrogen atmosphere at a pressure of 20,000 N cm -2 .
• the abrasive coating was molded at 300 ° C and not subjected to post-curing.
• a 24-station Breton machine was used to equip station No. 9 Bobble head segments made. On this grinding and polishing line in Wet sanding with water as a detergent Granite slabs with medium machinability in one pass processed.
• a mixture of 8.5 volume percent tin powder of the type "75F” from Pometon / France with an average grain size of 30 my, 51.5 volume percent, 80/20 bronze of the type "25GR” from Poudmet / France was used to produce the abrasive coatings , with an average grain size of 50 my, 40 volume percent powder resin of the type "Vespel SP1A” from DU Pont / USA with an average grain size of 50 my and diamond abrasive grain of the type "MDAS" from De Beers / Germany with the grain size FEPA D64 (US mesh 230/270), mixed in a Turbula mixer for 20 minutes.
• the raw materials were pre-dried and mixed without additives.
• This abrasive coating mixture was cold pre-pressed with 2000 N cm -2 in the mold.
• the abrasive coating mixture was then sintered in the same mold at 490 ° C and a holding time of 20 minutes in a nitrogen atmosphere at 22,000 N cm -2 .
• the grinding surfaces were pressurelessly hardened under a nitrogen atmosphere and at temperatures of 300-400 ° C. for 16 hours.
• the advantages of metal binding can the advantages of synthetic resin binding largely in one tool be realized. This is how the higher binding force of the metallic network occurs together with the elasticity and vibration damping effect of Resin bond at the same time.
• the compressive stress of the invention Grinding surfaces can be increased. Through the coherent A good thermal balance of the metallic bond network takes place Grinding temperature.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Ceramic Engineering (AREA)
• Inorganic Chemistry (AREA)
• Polishing Bodies And Polishing Tools (AREA)

Applications Claiming Priority (4)

Publications (2)

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• 1996
  • 1996-02-14 AT AT0025396A patent/AT403671B/de not_active IP Right Cessation
• 1997
  • 1997-02-07 DE DE59708987T patent/DE59708987D1/de not_active Expired - Fee Related
  • 1997-02-07 EP EP97901222A patent/EP0820364B1/de not_active Expired - Lifetime
  • 1997-02-07 WO PCT/IB1997/000099 patent/WO1997029886A1/de active IP Right Grant
  • 1997-02-07 BR BR9702077A patent/BR9702077A/pt not_active Application Discontinuation
  • 1997-02-07 US US08/973,085 patent/US6063148A/en not_active Expired - Fee Related

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