An automatic grinding apparatus includes: a grinding wheel configured to grind a workpiece; a support configured to support the workpiece; a feeding device configured to change a relative position between the grinding wheel and the workpiece; and a control device configured to, before processing using the grinding wheel is started, calculate a range in which the grinding wheel and the support are relatively moved on the basis of information on positions of the workpiece and the grinding wheel detected by a first detector, a second detector, and a third detector, move the grinding wheel or the support by performing numerical control with respect to the feeding device, and automatically start the processing using the grinding wheel.

An automatic grinding apparatus includes: a grinding wheel configured to grind a workpiece; a support configured to support the workpiece; a feeding device configured to change a relative position between the grinding wheel and the workpiece; and a control device configured to, before processing using the grinding wheel is started, calculate a range in which the grinding wheel and the support are relatively moved on the basis of information on positions of the workpiece and the grinding wheel detected by a first detector, a second detector, and a third detector, move the grinding wheel or the support by performing numerical control with respect to the feeding device, and automatically start the processing using the grinding wheel.

A grinding wheel is suited for shaping glass, notably glass that is less than or equal to 4 mm thick. This grinding wheel has at least one abrasive portion formed of at least one metal binder and of diamonds distributed in the binder. The binder has a Rockwell B hardness of between 95 and 105 and is tungsten-based. The diamonds have a size of between 75 and 95 m and a concentration of between 2.2 ct/cm.sup.3 and 2.64 ct/cm.sup.3. Glass, in particular for shaping motor-vehicle glazing units, can be shaped with this grinding wheel, making it possible to achieve travel speeds greater than or equal to 30 m/min.

A grinding wheel is suited for shaping glass, notably glass that is less than or equal to 4 mm thick. This grinding wheel has at least one abrasive portion formed of at least one metal binder and of diamonds distributed in the binder. The binder has a Rockwell B hardness of between 95 and 105 and is tungsten-based. The diamonds have a size of between 75 and 95 m and a concentration of between 2.2 ct/cm.sup.3 and 2.64 ct/cm.sup.3. Glass, in particular for shaping motor-vehicle glazing units, can be shaped with this grinding wheel, making it possible to achieve travel speeds greater than or equal to 30 m/min.

A method for simultaneously cutting a multiplicity of slices from a cylindrical workpiece, along strictly convex cutting faces, by supplying a suspension of hard substances in a carrier liquid, as cutting medium, to wire portions, while the wire portions, having a longitudinal tension, define a relative motion to the workpiece as a result of wire guide roller rotation with continual alternation between a first direction of rotation and a second direction of rotation, which is opposite to the first direction of rotation, wherein, during the rotation in the first direction, the wire is moved a first length, and during the rotation in the second direction, the wire is moved a second length, and the second length is shorter than the first, and at the cutting operation start a first longitudinal wire tension is greater than a second longitudinal tension at the end.

An abrasive article includes a bonded abrasive body having abrasive particles comprising microcrystalline alumina (MCA) contained within a bond material. In an embodiment, the bonded abrasive body has a strength ratio (MOR/MOE) of at least about 0.80. Additionally, the bonded abrasive body may have a MOR of at least 40 MPa for a MOE or at least about 40 GPa and the bonded abrasive body may be capable of grinding a workpiece that includes metal at a speed of at least about 60 m/s at a material removal rate of at least about 0.4 in.sup.3/min/in (258 mm.sup.3/min/mm).

An abrasive article includes a bonded abrasive body having abrasive particles comprising microcrystalline alumina (MCA) contained within a bond material. In an embodiment, the bonded abrasive body has a strength ratio (MOR/MOE) of at least about 0.80. Additionally, the bonded abrasive body may have a MOR of at least 40 MPa for a MOE or at least about 40 GPa and the bonded abrasive body may be capable of grinding a workpiece that includes metal at a speed of at least about 60 m/s at a material removal rate of at least about 0.4 in.sup.3/min/in (258 mm.sup.3/min/mm).