Minnesota Mining and Manufacturing Company

Todd A Berg

Donley D Rowenhorst

William Keith Leonard

James G Berg

A method of making abrasive particles having a specified shape and abrasive articles containing abrasive particles having a specified shape. The method for preparing such an abrasive particle comprises the steps of: (a) providing a dispersion containing particles of a precursor of alpha alumina, preferably particles of alpha alumina monohydrate, in a liquid, which liquid comprises a volatile component; (b) providing a mold having a first surface and a second surface opposed to said first surface, said first surface having an opening to a mold cavity having a specified shape; (c) introducing the dispersion into said mold cavity; (d) removing a sufficient portion of the volatile component of the liquid from the dispersion while the dispersion is in the mold cavity, to form a precursor of an abrasive particle having approximately the same shape as the shape of the recess of the mold cavity; (e) removing the precursor of the abrasive particle from the recess of the mold; (f) calcining the removed precursor of the abrasive particle; and (g) sintering the calcined precursor to form the desired abrasive particle.

Shaped abrasive particles and method of making same

An abrasive article comprising a binder and abrasive grits, wherein the abrasive grits comprise abrasive particles having specified shapes. Coated abrasive articles of this invention comprise a backing having at least one layer of abrasive material adhered thereto by means of a binder. A portion of this layer contains abrasive particles having specified shapes. It is preferred that the geometric shape of these abrasive particles be triangular. For triangular-shaped particles, about 35% to about 65% of the particles are oriented with a vertex pointing away from the backing and a base in contact with the binder, with about 35% to about 65% of the particles being oriented with a base pointing away from the backing and a vertex in contact with the binder. It is believed that this configuration brings about the result that the sum of the surface areas of each of the particles in contact with the workpiece remains essentially constant during use, even though the surface area of each individual abrasive particle in contact with the workpiece varies during use. The use of the abrasive particles described herein minimizes the formation of flat surfaces on the cutting regions of the abrasive grits.

Abrasive article containing shaped abrasive particles

A method of making abrasive particles having a specified shape and abrasive articles containing abrasive particles having a specified shape. The method for preparing such an abrasive particle comprises the steps of: (a) providing a dispersion of comprising particles that can be converted into alpha alumina, preferably particles of alpha alumina monohydrate, in a liquid, which liquid comprises a volatile component, preferably water; (b) providing a mold having a first generally planar surface and a second surface opposed to said first surface, said first surface having an opening to a mold cavity having a specified shape; (c) introducing the dispersion into the mold cavity in such a way that no exposed surface of the dispersion that has been introduced into the mold will extend substantially beyond the plane formed by the first surface of the mold; (d) removing a sufficient portion of the volatile component from the dispersion while the dispersion is in the mold cavity, thereby forming a precursor of an abrasive particle having a shape approximately corresponding to the shape of the mold cavity; (e) removing the precursor of the abrasive particle from the mold cavity; (f) calcining the removed precursor of the abrasive particle; and (g) sintering the calcined precursor to form the desired abrasive particle.

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St. Louis Park, MN, United States of America

Todd A Berg