An annular grindstone includes a grindstone portion including a binding material, and abrasive grains which are dispersed into the binding material to be fixed, in which the binding material contains a nickel-iron alloy. Preferably, a contained ratio of iron in the nickel-iron alloy is in a range of 5 wt % or more to less than 60 wt %. More preferably, a contained ratio of iron in the nickel-iron alloy is in a range of 20 wt % or more to 50 wt % or less. Preferably, the annular grindstone includes the grindstone portion only. In addition, the annular grindstone further includes an annular base including a grip portion, in which the grindstone portion is exposed at an outer peripheral edge of the annular base.

A bonded abrasive wheel comprises magnetizable abrasive particles retained in an organic binder. The bonded abrasive wheel has a central portion adjacent to a central hub, an outer circumference and a rotational axis extending through the central hub. The magnetizable abrasive particles adjacent to the central hub are aligned at an average angle of less than 35 degrees with respect to the rotational axis, and the magnetizable abrasive particles adjacent to the outer circumference of the bonded abrasive wheel are aligned at an average angle that is from 35 and 90 degrees, inclusive, with respect to the rotational axis. Methods of making a bonded abrasive wheel are also disclosed.

A bonded abrasive wheel comprises magnetizable abrasive particles retained in an organic binder. The bonded abrasive wheel has a central portion adjacent to a central hub, an outer circumference and a rotational axis extending through the central hub. The magnetizable abrasive particles adjacent to the central hub are aligned at an average angle of less than 35 degrees with respect to the rotational axis, and the magnetizable abrasive particles adjacent to the outer circumference of the bonded abrasive wheel are aligned at an average angle that is from 35 and 90 degrees, inclusive, with respect to the rotational axis. Methods of making a bonded abrasive wheel are also disclosed.

A multi blade that processes semiconductor packages into a desired shape while dividing a package substrate includes plural cutting blades that divide the package substrate into the individual semiconductor packages and a spacer provided between two cutting blades adjacent to each other, and is configured in such a manner that the cutting blades and the spacer have the same rotation axis center. The outer surface of the spacer is formed into a transfer shape of the semiconductor package and is covered by an abrasive grain layer, and the upper surface of the package substrate is ground by the outer surface of the spacer simultaneously with cutting of the package substrate by the plural cutting blades.

A bonded abrasive wheel comprises magnetizable abrasive particles retained in a first organic binder. The bonded abrasive wheel has a central portion adjacent to a central hub, an outer circumference, and a rotational axis extending through the central hub. A majority of the magnetizable abrasive particles are substantially parallel to the rotational axis. A method of making the bonded abrasive wheel is also disclosed.

A bonded abrasive wheel comprises magnetizable abrasive particles retained in a first organic binder. The bonded abrasive wheel has a central portion adjacent to a central hub, an outer circumference, and a rotational axis extending through the central hub. A majority of the magnetizable abrasive particles are substantially parallel to the rotational axis. A method of making the bonded abrasive wheel is also disclosed.

A rare earth magnet block is cutoff machined into pieces by rotating a plurality of cutoff abrasive blades. Improvements are made by starting the machining operation from the upper surface of the magnet block downward, interrupting the machining operation, turning the magnet block upside down, placing the magnet block such that the cutoff grooves formed before and after the upside-down turning may be aligned with each other, and restarting the machining operation from the upper surface of the upside-down magnet block downward until the cutoff grooves formed before and after the upside-down turning merge with each other.

A cutting disk for a machine tool for the cutting and/or grinding of workpieces, in particular consisting of materials such as cellulose or wood, includes a disk-shaped main body that has a radially inside receiving region and a radially outside work zone. The radially outside work zone includes at least one first active region and at least one second active region. The first active region and the second active region each have at least one cutting element that is configured as a cutting grain or as a cutting tooth. The second active region rises radially or protrudes radially in relation to the first active region.

A cutting disk for a machine tool for the cutting and/or grinding of workpieces, in particular consisting of materials such as cellulose or wood, includes a disk-shaped main body that has a radially inside receiving region and a radially outside work zone. The radially outside work zone includes at least one first active region and at least one second active region. The first active region and the second active region each have at least one cutting element that is configured as a cutting grain or as a cutting tooth. The second active region rises radially or protrudes radially in relation to the first active region.

A curable composition comprises a phenolic resin and isocyanate-functionalized abrasive particles. The isocyanate-functionalized abrasive particles consist of the reaction product of at least one isocyanate-functional organosilane and abrasive particles. Abrasive articles and methods of making them using the isocyanate-functionalized abrasive particles are also disclosed.