Minnesota Mining and Manufacturing Company

Donley D Rowenhorst

William Keith Leonard

Todd A Berg

James G Berg

David E Broberg

Gunther H Dierssen

Thomas Gabor

Jerald A Scherger

Donald R Winberg

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

The present invention relates to an apparatus and method for extruding a Bingham plastic-type material through a die having an auger rotationally mounted therein.

Method and apparatus for extruding bingham plastic-type materials

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.

Improved granular abrasive material comprises silicon carbide particles at least partially coated with an integral, durable surface layer of a hard refractory material comprising metal nitride or carbide. Hard refractory materials which provide a useful coating include, for example, silicon nitride or carbide, titanium nitride or carbide, sialon, and others. The surface layer is preferably provided by chemical vapor deposition, most preferably utilizing a fluidized bed. The improved granular abrasive material is particularly useful in various abrasive products such as coated abrasive products, nonwoven abrasive products and abrasive grinding wheels.

Growing community of inventors

Maplewood, MN, United States of America

Donley D Rowenhorst