A grinding wheel for grinding a workpiece containing a ductile material, the grinding wheel including an annular wheel base having a fixed end adapted to be fixed to a lower end of a spindle and having a free end adapted to face the workpiece to be ground, and a plurality of grindstones each shaped as a rectangular plate, disposed on the free end of the annular wheel base, and arrayed at predetermined intervals with respective longer sides disposed along circumferential directions of the wheel base. Each of the grindstones includes an electroformed grindstone shaped as a rectangular plate and made up of abrasive grains secured together by nickel plating, and has a thickness of 1 mm or smaller and a value ranging from 5 inclusive to 35 exclusive that is represented by a ratio of a height from the free end to the thickness.

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.

Disclosed are an additive raw material composition and an additive for superhard material product, a composite binding agent, a superhard material product, a self-sharpening diamond grinding wheel and a method for manufacturing the same. The raw material composition consisting of components in following mass percentage: Bi.sub.2O.sub.3 25%˜40%, B.sub.2O.sub.3 25%˜40%, ZnO 5%˜25%, SiO.sub.2 2%˜10%, Al.sub.2O.sub.3 2%˜10%, Na.sub.2CO.sub.3 1%˜5%, Li.sub.2CO.sub.3 1%˜5%, MgCO.sub.3 0%˜5%, and CaF.sub.2 1%˜5%. The composite binding agent is prepared from the additive and a metal composite binding agent. The self-sharpening diamond grinding wheel prepared from the composite binding agent has high self-sharpness, high strength, and fine texture, is uniformly consumed during the grinding process, does not need to be trimmed during the process of being used, and maintains good grinding force all the time, fundamentally solving the problems of long trimming time and high trimming cost of the diamond grinding wheel (FIG. 1).

Disclosed are an additive raw material composition and an additive for superhard material product, a composite binding agent, a superhard material product, a self-sharpening diamond grinding wheel and a method for manufacturing the same. The raw material composition consisting of components in following mass percentage: Bi.sub.2O.sub.3 25%˜40%, B.sub.2O.sub.3 25%˜40%, ZnO 5%˜25%, SiO.sub.2 2%˜10%, Al.sub.2O.sub.3 2%˜10%, Na.sub.2CO.sub.3 1%˜5%, Li.sub.2CO.sub.3 1%˜5%, MgCO.sub.3 0%˜5%, and CaF.sub.2 1%˜5%. The composite binding agent is prepared from the additive and a metal composite binding agent. The self-sharpening diamond grinding wheel prepared from the composite binding agent has high self-sharpness, high strength, and fine texture, is uniformly consumed during the grinding process, does not need to be trimmed during the process of being used, and maintains good grinding force all the time, fundamentally solving the problems of long trimming time and high trimming cost of the diamond grinding wheel (FIG. 1).

The invention relates to a disk-shaped cutting tool, to a radial cutting method for machining axially elongated workpieces, to a cutting device and to a use of a disk-shaped cutting tool. A disk-shaped cutting tool according to the invention has defined flexibility and a defined impact. In a radial cutting process according to the invention, lateral deflection of the axially stationary rotating tool brings the tool, by means of the at least one laterally applied grinding and polishing surface, into axial effective contact with the workpiece to be machined. In a cutting device according to the invention, the cutting tool can be moved only radially to machine the workpiece. A use according to the invention of a disk-shaped tool serves the purpose of specimen preparation and subsequent surface analysis on a workpiece cut to length.

An abrasive disc (2) for grinding and/or polishing hard floor surfaces of stone, concrete or similar, the abrasive disc including a plurality of fixing means (3, 4) for mounting detachably mountable carrier plates (9), each with abrasive elements (11), to a grinding side (2a) of the abrasive disc (2), each carrier plate having a specific fixing geometry, characterized by that the fixing means are disposed at least two separate distances from the centre of the disc, first fixing means (3) at a first predetermined distance (r1) and second fixing means (4) at a second predetermined distance (r2), said second predetermined distance (r2) being shorter than the first (r1), so that the carrier plates (9) will be arranged in at least to rows, a first outer row and a second inner row, and each fixing mean (3, 4) includes a groove (7) providing a female coupling adapted for corresponding male couplings of the carrier plates (9).

An abrasive disc (2) for grinding and/or polishing hard floor surfaces of stone, concrete or similar, the abrasive disc including a plurality of fixing means (3, 4) for mounting detachably mountable carrier plates (9), each with abrasive elements (11), to a grinding side (2a) of the abrasive disc (2), each carrier plate having a specific fixing geometry, characterized by that the fixing means are disposed at least two separate distances from the centre of the disc, first fixing means (3) at a first predetermined distance (r1) and second fixing means (4) at a second predetermined distance (r2), said second predetermined distance (r2) being shorter than the first (r1), so that the carrier plates (9) will be arranged in at least to rows, a first outer row and a second inner row, and each fixing mean (3, 4) includes a groove (7) providing a female coupling adapted for corresponding male couplings of the carrier plates (9).

Method for producing a green body for a machining segment (51) from a powdered or granular first matrix material (56) and first hard material particles (57), the machining segment being connected by an underside (61) to a basic body of a machining tool. The machining segment (51) has a projection (Δ) of the first hard material particles (57) on an upper side (62) opposite from the underside (61).

Polishing pads having discrete and selectively arranged regions of varying porosity within a continuous phase of polymer material are provided herein. In one embodiment a polishing pad features a plurality of polishing elements each comprising a polishing surface and sidewalls extending downwardly from the polishing surface to define a plurality of channels disposed between the polishing elements, wherein one or more of the polishing elements is formed of a continuous phase of polymer material having one or more first regions comprising a first porosity and a second region comprising a second porosity, wherein the second porosity is less than the first porosity.

A method of grinding a workpiece includes a holding step of holding the workpiece on a flat holding surface of a holding table and a grinding step of rotating a grinding wheel to turn grindstones along an annular track while rotating the holding table, and bringing the grindstones into grinding contact with an upper surface of the workpiece to thereby grind the workpiece. The grinding step includes the step of bringing the grindstones into grinding contact with the upper surface of the workpiece in a state where the annular track is closest to the holding surface in an area between a point above a center of the holding surface and a point above an outer circumferential end of the holding surface.