Nonwoven abrasives consist of abrasive grains adhered with resin to the internal fiber surfaces of a nonwoven textile backing. Products include abrasive brushes, belts, discs, flap wheels, non-woven wheels, convoluted wheels, laminated cotton wheels, unified or unitized wheels, pads, rolls and sheets. Abrasive belts are mounted on rotating wheels or pulleys and used for surface finishing, sanding, and grinding. Abrasive discs are usually round, although specialized flower petal shapes are used for ophthalmic applications. Flap wheels consist of a series of coated abrasive flaps radiating out from the center of the wheel where the flaps are bonded together. Convolute wheels are fabricated by wrapping layers of a nonwoven abrasive around a mandrel and then densifying the product. Unified wheels are also made of dense, stacked layers. Laminated cotton wheels are used in surface conditioning or finishing applications. Abrasive pads are nonwoven abrasives that are designed to be used by hand and are usually round, rectangular, or square.
Differences in Nonwoven Abrasives
Nonwoven abrasives use several types of abrasive grains and differ in terms of coarseness. Aluminum oxide, a common industrial mineral, is used either individually or with other materials to form ceramic grains. Aluminum oxide is also combined with emery and crocus to produce abrasives suitable for finishing applications. Silicon carbide is harder than aluminum oxide, but more friable than fused aluminum oxide grains. Typically, silicon carbide is used in non-ferrous applications. There are several degrees of coarseness for non-woven surface conditioning abrasives. Coarse grit products have a grit size range between 50 – 80 grit and are designed for aggressive cutting, heavy duty surface preparation, and descaling applications. Medium grit products have a grit size range between 100 – 150 grit and are used for cleaning, rust removal, blending, and light cutting applications. Fine grit, nonwoven products have a grit size range between 180 – 220 grit. Very fine (240 - 360 grit), ultrafine (600 grit) and micro-fine (800 - 1200 grit) products are used in polishing and paint preparation applications.
Nonwoven abrasives differ in terms of mounting styles, features, materials abraded, and dimensions. Hook and loop mounting attaches the abrasive with a hook and loop fabric. Bore / center mounting provides a central hole for mounting with a mandrel, arbor, spindle or shaft. Products with an integral mandrel, pin, arbor or shaft are also available. Some nonwoven abrasives use quick change mechanisms, adhesive, or pressure sensitive adhesive (PSA) backings. Others contain interleaved layers with different abrasive types or grit sizes. Typically, suppliers indicate whether nonwoven abrasive products and materials are designed to abrade ceramics, glass, metal, paint, plastic, wood, or composite materials. Outer diameter, bore, width, and length are important dimensions for nonwoven abrasives.