Abrasive Tools Having a Permeable Structure

• US 20100196700A1
• Filed: 04/08/2010
• Published: 08/05/2010
• Est. Priority Date: 09/30/2005
• Status: Active Grant

• Current Assignee: Saint-Gobain Abrasives Incorporated (Compagnie De Saint-Gobain)
• Original Assignee: Saint-Gobain Abrasives Incorporated (Compagnie De Saint-Gobain)
• Inventors: Jeevanantham, Muthu, Orlhac, Xavier, Krause, Russell, Wu, Mianxue
• Granted Patent: US 8,475,553 B2
• Time in Patent Office: Days
• US Class Current: 428/329
• CPC Class Codes: B24D 18/0009 using moulds or presses
• CPC Class Codes: B24D 3/00 Physical features of abrasive bodies, or sheets, e.g. abrasive surfaces of special nature; Abrasive bodies or sheets characterised by their constituents
• CPC Class Codes: Y10T 428/257 Iron oxide or aluminum oxide

Abstract

A bonded abrasive tool comprises a blend of abrasive grains and a bond component. The blend of abrasive grains comprises a filamentary sol-gel alumina abrasive grain and agglomerated abrasive grain granules. A bonded abrasive tool comprising an agglomerate of filamentary sol-gel alumina abrasive and non-filamentary abrasive grains, and a bond component is also disclosed. The filamentary sol-gel alumina abrasive grain has a length-to-cross-sectional-width aspect ratio of greater than 1.0. The agglomerated abrasive grain granules comprise a plurality of abrasive grains held in a three-dimensional shape by a binding material. A method of making such a bonded abrasive tool as described above is also disclosed.

Claims

1. A method of making a bonded abrasive tool, comprising:

a) forming a blend of abrasives, the blend comprising;

i) agglomerates including filamentary sol-gel alumina abrasive grain having a length-to-cross-sectional-width aspect ratio of at least about 2;

1 and non-filamentary abrasive grains; and

ii) agglomerated abrasive grain granules including a plurality of abrasive grains held in a three-dimensional shape by a binding material, the abrasive grains having a length-to-cross-sectional-width aspect ratio of about 1.0, wherein a total amount of non-filamentary abrasive grains present in the blend is less than or equal to 50% of the weight of the blend;

b) combining the blend of abrasives and a bond component;

c) molding the combined blend of abrasives and bond component into a shaped composite comprising at least about 35 volume percent to 80 volume percent porosity; and

d) heating the shaped composite to form the bonded abrasive tool.

2. The method of claim 1, wherein the bonded abrasive tool comprises about 35-80 volume percent total porosity.

3. The method of claim 2, wherein the bonded abrasive tool comprises at least about 30 volume percent of the total porosity is interconnected porosity.

4. The method of claim 1, wherein the melting temperature of the binding material is in a range of between about 800°

C. and about 1300°

C.

5. The method of claim 1, wherein the agglomerated abrasive grain granules are sintered agglomerated granules.

6. The method of claim 5, further comprising the steps of making the sintered agglomerated granules:

feeding the abrasive grains and binding material into a rotary calcination kiln at a controlled feed rate;

rotating the kiln at a controlled speed;

heating the mixture at a heating rate determined by the feed rate and the speed of the kiln to a temperature in a range of between about 80°

C. and about 1,300°

C.;

tumbling the grain and the binding material in the kiln until the binding material adheres to the grains and a plurality of grains adhere together to create the sintered agglomerated granules; and

recovering the sintered agglomerated granules from the kiln.

7. The method of claim 6, wherein the step of feeding the abrasive grains and binding material into a rotary calcination kiln includes the steps of making a substantially uniform mixture of the abrasive grains and the binding material and then feeding the mixture into the rotary calcination kiln.

8. A bonded abrasive tool comprising:

a) a blend of abrasive grains including;

i) agglomerates of filamentary sol-gel alumina abrasive grain having a length-to-cross-sectional-width aspect ratio of at least about 2;

1 held by a binding material; and

ii) agglomerated abrasive grain granules including a plurality of abrasive grains held in a three-dimensional shape by the binding material, the abrasive grains having a length-to-cross-sectional-width aspect ratio of about 1.0;

b) a bond; and

c) about 50 volume percent to 75 volume percent porosity.

9. The bonded abrasive tool of claim 8, wherein the filamentary sol-gel alumina abrasive grain has an aspect ratio of at least about 4:

1 and comprises predominantly alpha alumina crystals having a size of less than about 2 microns.

10. The bonded abrasive tool of claim 8, wherein the agglomerates of the filamentary sol-gel alumina abrasive grain further comprise a secondary non-filamentary abrasive grain.

11. The bonded abrasive tool of claim 8, wherein the bond and the binding material are the same.