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.

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 grinding apparatus includes: a holding table for holding a workpiece thereon; a grinding unit including a grinding wheel for grinding the workpiece held on the holding table, the grinding wheel including a grinding stone made of abrasive grains and grains of photocatalyst bonded by a vitrified bonding material; a grinding water supply unit configured to supply grinding water to the grinding stone when the workpiece held on the holding table is ground by the grinding unit; and a light applying unit disposed adjacent to the holding table and configured to apply light to a grinding surface of the grinding stone while the workpiece held on the holding table being ground.

The present invention relates to a polishing system (100) for providing a polishing finish to a concrete surface, said system comprises a pad lock (2) which, one a second surface (6) thereof, comprises a number of protrusions (32) which are able to enter into engagement with a voids (16) arranged on a first surface (12) of a pad (10) placed between a fixing ring and said pad lock. The use of such a system provides a higher degree of integrity during use of said polishing system.

A grinding tool includes a substrate, and at least an abrasive particle affixed to the substrate. The abrasive particle has a base, and four tips adjacent to one another protruding from the base, the base having a cavity of a generally cross shape extending between the four tips, the cavity including a material discharge surface disposed between two adjacent ones of the four tips, the material discharge surface being located at an end of the cavity and adjacent to a side surface of the base, an inner material angle between the material discharge surface and the side surface being between about 120 degrees and about 160 degrees. Moreover, embodiments described herein include a method of manufacturing the grinding tool.

A transmission arrangement (113) comprising a first axle (24) that is rotatable about a first axis (33) and is connected to a first pulley (25) that is arranged to drive an endless power transferring means (26) that further is adapted to drive a second pulley (27) that is rotatable about a second axis (34), where the transmission arrangement (113) comprises a first idle pulley (101) and a second idle pulley (102) which both are adapted to guide the endless power transferring means (26), where the first idle pulley (101) is rotatable around a first idle pulley axis (103) and the second idle pulley (102) is rotatable around a second idle pulley axis (104), where the distance between the idle pulley axes (103, 104) is fixed and where the idle pulley axes (103, 104) are pivotable around a common pivot axis (105), wherein the first pulley (25) is positioned between the idle pulleys (101, 102) and the second pulley (27) such that a distance between any one of the idle pulley axes (103, 104) and the second axis (34) exceeds a distance between any one of the idle pulley axes (103,104) and the first axis (33).

A coated abrasive disc includes a disc backing and an abrasive layer disposed thereon. The abrasive layer comprises abrasive elements secured to a major surface of the disc backing by at least one binder material. The abrasive elements are disposed at contiguous intersections of horizontal and vertical lines of a rectangular grid pattern. At least 70 percent of the intersections have one of the abrasive elements disposed thereat. Each of the abrasive elements has two triangular abrasive platelets. Each one of the triangular abrasive platelets has respective top and bottom surfaces connected to each other, and separated by, three sidewalls. On a respective basis, one sidewall of at least 90 percent of the triangular abrasive platelets is disposed facing and proximate to the disc backing. The abrasive elements are arranged such that the triangular abrasive platelets in orthogonally adjacent abrasive elements have a Z-axis rotational orientation within 10 degrees of perpendicular to each other. Methods of making and using the coated abrasive disc are also disclosed.

A coated abrasive disc includes a disc backing and an abrasive layer disposed thereon. The abrasive layer comprises abrasive elements secured to a major surface of the disc backing by at least one binder material. The abrasive elements are disposed at contiguous intersections of horizontal and vertical lines of a rectangular grid pattern. Each abrasive element has two triangular abrasive platelets, each having respective top and bottom surfaces connected to each other, and separated by, three sidewalls. On a respective basis, one sidewall of the triangular abrasive platelets is disposed facing and proximate to the disc backing. A first portion of the abrasive elements is arranged in alternating first rows wherein the triangular abrasive platelets are disposed lengthwise aligned with the vertical lines. A second portion of the abrasive elements is arranged in alternating second rows wherein the triangular abrasive platelets are disposed lengthwise aligned with the horizontal lines. The first and second rows repeatedly alternate along the vertical lines. Methods of making and using the coated abrasive disc are also disclosed.

A coated abrasive disc includes a disc backing and an abrasive layer disposed thereon. The abrasive layer comprises abrasive elements secured to a major surface of the disc backing by at least one binder material. The abrasive elements are disposed at contiguous intersections of horizontal and vertical lines of a rectangular grid pattern. Each abrasive element has two triangular abrasive platelets, each having respective top and bottom surfaces connected to each other, and separated by, three sidewalls. On a respective basis, one sidewall of the triangular abrasive platelets is disposed facing and proximate to the disc backing. A first portion of the abrasive elements is arranged in alternating first rows wherein the triangular abrasive platelets are disposed lengthwise aligned with the vertical lines. A second portion of the abrasive elements is arranged in alternating second rows wherein the triangular abrasive platelets are disposed lengthwise aligned with the horizontal lines. The first and second rows repeatedly alternate along the vertical lines. Methods of making and using the coated abrasive disc are also disclosed.

A clamping device (10) for the axial (AR) clamping of a tool disk (300) on a flange (30) associated with a drive spindle (20) of a hand-held power tool (100), wherein the clamping device (100) has a screw (2), which is to be screwed into an internal thread (22) of the drive spindle (20) to securely clamp the tool disk (300), wherein the screw (2) is mounted in a coupling module (1) of the clamping device (10), wherein the coupling module (1) has an internal contour (16) which is paired or can be paired positively with the drive spindle (20) for conjoint rotation in the circumferential direction (U).