Disc-shaped sanding element (1) and method for manufacturing this sanding element (1) with a circular circumference with at least two layers (4,5,6) bonded to each other containing abrasive grains (11, 12), wherein these layers (4,5,6) extend at least to the circumference of the sanding element (1) in order to form a sanding edge (8) on this circumference (7), wherein each of these layers (4,5,6) has layer properties including compressibility, abrasive grain density, abrasive grain size and grain material. The layers (4,5,6) contain a three-dimensional thread or fibre structure in which said abrasive grains (11,12) are distributed, wherein adjacent layers (4,5,6) have at least one different layer property.

A grinding disc includes an inner layer (20) which is made of grindable material (containing abrasive particles) and an outer layer (20) which covers at least a portion of the surface of the inner layer (50) and which is made of non-grindable material (i.e. not-containing abrasive grain).

A problem solved is realizing a self-sharpening of a rotary grindstone in the most efficient manner and allowing sequential appearances of sharp cutting faces. To solve the problem, the invention provides a manufacturing method of a rotary grindstone 1 with one or more sheets of glass cloth 4 as a reinforcing material, wherein the glass cloth 4 is weaved by thirl plain weave/twill weave or leno weave composed of twist yarns having a diameter of 0.1 mm or less and formed in meshes with lengthwise and crosswise lengths of 2.0 mm or less, and attaching liquid resin to the glass cloth 4 to produce a prepreg 6, attaching resin-coat abrasive grains to both faces of the prepreg 6, and pressing the prepreg 6 in a press machine and further performing predetermined press working in a metal mold, performing baking.

A problem solved is realizing a self-sharpening of a rotary grindstone in the most efficient manner and allowing sequential appearances of sharp cutting faces. To solve the problem, the invention provides a manufacturing method of a rotary grindstone 1 with one or more sheets of glass cloth 4 as a reinforcing material, wherein the glass cloth 4 is weaved by thirl plain weave/twill weave or leno weave composed of twist yarns having a diameter of 0.1 mm or less and formed in meshes with lengthwise and crosswise lengths of 2.0 mm or less, and attaching liquid resin to the glass cloth 4 to produce a prepreg 6, attaching resin-coat abrasive grains to both faces of the prepreg 6, and pressing the prepreg 6 in a press machine and further performing predetermined press working in a metal mold, performing baking.

An abrasive article has an abrasive portion with an organic bond and abrasive particles. The abrasive article has a non-abrasive portion (NAP) mounted to the abrasive portion. The NAP includes molding compound (MC) having chopped strand fibers (CSF). The CSF can be coated with a thermoplastic coating having a loss on ignition (LOI) of at least about 2.4 wt %, and the NAP having no abrasive particles. The NAP can include an MC having no abrasive particles with a MOHS scale hardness of at least about 9. The NAP may include CSF coated with a primary coating and a secondary coating on the primary coating. The NAP may have an outer diameter that is at least half of but not greater than an outer diameter of the abrasive article.

An abrasive article has an abrasive portion with an organic bond and abrasive particles. The abrasive article has a non-abrasive portion (NAP) mounted to the abrasive portion. The NAP includes molding compound (MC) having chopped strand fibers (CSF). The CSF can be coated with a thermoplastic coating having a loss on ignition (LOI) of at least about 2.4 wt %, and the NAP having no abrasive particles. The NAP can include an MC having no abrasive particles with a MOHS scale hardness of at least about 9. The NAP may include CSF coated with a primary coating and a secondary coating on the primary coating. The NAP may have an outer diameter that is at least half of but not greater than an outer diameter of the abrasive article.

The invention concerns a tool for machining of materials, specifically a grinding tool, which has a substantially rotationally symmetrical shape with respect to a rotation axis (R), the tool comprising an outer shell centered about the rotation axis and defining an internal space therein, wherein at least a part of a surface of the outer shell is provided with an abrasive coating or component, wherein the outer shell encases an internal skeleton structure in the internal space, the internal skeleton being integral with the outer shell and defining void volumes in the internal space thereby establishing material and void volumes of the internal space, and wherein the material to void ratio M/V is distributed substantially identically along each radius (r) centered around the rotation axis (R) and its corresponding symmetrical radius (r). The invention also concerns a method for producing such tool.

The invention concerns a tool for machining of materials, specifically a grinding tool, which has a substantially rotationally symmetrical shape with respect to a rotation axis (R), the tool comprising an outer shell centered about the rotation axis and defining an internal space therein, wherein at least a part of a surface of the outer shell is provided with an abrasive coating or component, wherein the outer shell encases an internal skeleton structure in the internal space, the internal skeleton being integral with the outer shell and defining void volumes in the internal space thereby establishing material and void volumes of the internal space, and wherein the material to void ratio M/V is distributed substantially identically along each radius (r) centered around the rotation axis (R) and its corresponding symmetrical radius (r). The invention also concerns a method for producing such tool.

A grinding wheel (20) includes at least a first reinforcing mesh (21) completely incorporated in at least a first layer of abrasive mixture (22) and at least a support element in contact with the first reinforcing mesh (21). The reinforcing element is constituted by an auxiliary mesh (23) provided with a face (232) in direct contact with the first reinforcing mesh (21).

A grinding wheel (20) includes at least a first reinforcing mesh (21) completely incorporated in at least a first layer of abrasive mixture (22) and at least a support element in contact with the first reinforcing mesh (21). The reinforcing element is constituted by an auxiliary mesh (23) provided with a face (232) in direct contact with the first reinforcing mesh (21).