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
  • B24D3/34—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
  • B24D3/346—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 utilised during polishing, or grinding operation
• • 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

Definitions

• the invention relates to abrasives with a flexible base, abrasive grains and at least partially abrasive fillers being held on the base by a binder, for example phenolic resin.
• a binder for example phenolic resin.
• the flexible underlays of such an abrasive are mostly made of tissue, paper or a nonwoven. Corundum is mostly used as the abrasive grain, and it is known to use both individual grains and abrasive grain agglomerates.
• the grinding performance of the abrasives material removal per unit of time
• the surface quality of the workpiece achieved with this change with the degree of wear of the abrasive.
• the surface quality is more important than the removal rate.
• the dulling of the abrasive grains increases and the roughness depth decreases.
• the service life of the abrasives represents a significant cost or quality factor.
• the coated abrasives tend to "coat" due to the chips removed from the workpiece. This leads to a reduction in the removal rate, deterioration of the workpiece surface and possibly failure of the grinding tool.
• coated abrasives generally grind cooler than bonded abrasives (grinding wheels) Damage to the workpiece surface (e.g. crack, discoloration) can occur with sensitive materials with high stock removal rates with a large contact area.
• halides e.g. bleach chloride, fluorspar, kyrolite, etc.
• chalcogenides e.g. pyrite antimony sulfides, zinc sulfide, molybdenum sulfide, selenides, tellurides, etc.
• low-melting metals e.g. lead, tin, low-melting mixed metals
• high-pressure lubricants e.g. Graphite, boron nitride
• an optimal abrasive filler must have favorable transition temperatures, favorable film-forming properties and chemically reactive cleavage products, that it and its secondary products should have the lowest possible toxicity and thus high MAK values, that it should be inexpensive and that its incorporation into it must be possible to bind the abrasive. Furthermore, the strength and grinding properties must be maintained even under unfavorable storage conditions (high temperature and air humidity).
• the applicant's AT-PS 366944 discloses the use of hygroscopic fillers which have very good abrasive properties.
• the disadvantage of these fillers is that in practice they have to be encased, which on the one hand is labor-intensive and thus expensive and on the other hand reduces the volume of the active grinding fillers which can be introduced into the grinding compound.
• a special object of the invention is to introduce fillers into an abrasive of the type mentioned at the outset which have the same effect as toxic fillers, e.g. Show lead compound, as well as the grinding active cooling properties of hygroscopic fillers e.g. ZnCl2, without being hygroscopic.
• chlorides are provided which are not hygroscopic. You can therefore do without expensive protective measures, such as coating with organic substances.
• this also has the advantage that there is more grinding-active filler in the grinding compound per unit mass. Due to the limited ability to bind and the amount of phenolic resin, it is not possible to incorporate unlimited amounts of fillers into the abrasive compound. The sheathing therefore reduces the volume of the grinding-active fillers in the already relatively low grinding mass of the flexible abrasive.
• the filler according to the invention is described in its use with conventional phenolic resin-bonded corundum as an abrasive grain.
• the abrasive mass rests on a flexible base, for example a tissue.
• three metal salts were melted together, ground and sieved in order to create the filler according to the invention, namely the salts were melted and the molten liquid was poured onto a metal plate, where it cooled very quickly, and after hardening the mixture was ground with a cross beater mill to form the new filler.
• the particles were then sieved to a fineness of 240 mesh US standard (63 my). Grinding belts with a fabric backing were produced in a manner known per se, these being equipped on the one hand with the new grinding-active fillers and on the other hand using standard fillers (kaolin, fluorspar, lithopone, chalk).
• a first sample was made using potassium tetrafluoroborate (KBF4) as the only abrasive filler in a conventional manner.
• KF4 potassium tetrafluoroborate
• This grinding wheel was the directional grinding wheel in relation to which the results of the other grinding wheels were measured.
• a base binder layer of an aqueous phenol resol was applied to a linen base material. Then synthetic corundum was applied with the P46 grain size, namely about 640 g / m2.
• the coating amount of the top layer was 115 g / m2 in all three samples.
• the grinding belts produced were subjected to comparative grinding on a test machine.
• the test machine worked at a grinding speed of 12 m / sec. The amount sanded was measured after a grinding time of 60 minutes. The result of Sample I was with
• Table 1 shows the 20% and 27% better effectiveness of fillers II and III compared to standard fillers.
• Table 1 sample filler Power % 1 KBF4 1oo% 2nd 4 KCl ⁇ MnS.ZnS 120% 3rd ZN2P2O7 ⁇ KCl 127%
• the filler could also be arranged in a third binder layer.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Polishing Bodies And Polishing Tools (AREA)

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Citations (11)

• 1988
  • 1988-12-30 EP EP88121884A patent/EP0375803A1/fr not_active Withdrawn
• 1989
  • 1989-06-21 EP EP19890111276 patent/EP0379633A3/fr not_active Withdrawn

Patent Citations (11)

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