A substrate warpage correction method according to this disclosure corrects warpage of a substrate without performing a process on a front surface of the substrate. The substrate warpage correction method includes a surface roughening of performing a surface roughening process on a rear surface of the substrate using a surface roughening processing apparatus configured to be able to perform the surface roughening process on the rear surface of the substrate, to form grooves in the rear surface to thereby correct the warpage of the substrate.

A machine (10) for grinding and/or polishing slabs of stone material, such as natural or agglomerated stone, ceramics or glass, comprises: a support bench (12) for the slabs to be machined. At least one working station (14) is provided above the support bench (12), said station comprising at least one pair of bridge support structures (16, 18) situated opposite each and arranged transversely on either side of the support bench (12). First means (19) are provided for performing a relative movement in the longitudinal direction of machining station (14) and slab on the support bench (12). The machine further comprises at least one beam (20, the two ends (22, 24) of which are supported by the support structures (16, 18), and at least one rotating spindle (26) with a sliding vertical axis mounted on the at least one beam (20). The beam (20) is movable transversely on the support structures (16, 18). The bottom end of the spindle (26) is provided with at least one tool-carrying support (28) rotating about the axis of rotation of the spindle (26). The machine is characterized in that it comprises second means (32) for performing a relative movement in the longitudinal direction of the at least one spindle (26) with respect to the support bench (12).

A floor polishing or grinding pad assembly is provided. In one aspect, a polishing or grinding pad assembly employs a fibrous pad, a reinforcement layer or ring, and multiple floor-contacting disks. In another aspect, the reinforcement layer includes a central hole through which the fibrous pad is accessible and the fibrous pad at the hole has a linear dimension greater than a linear dimension of one side of the adjacent reinforcement layer. In yet another aspect, at least one of the floor-contacting disks has an angle offset from that of a base surface of the disk, the fibrous pad and/or the reinforcement layer. A further aspect employs a smaller set of disks alternating between and/or offset from a larger set of the disks. In another aspect, the reinforcement layer includes a wavy or undulating internal edge shape.

A portable power tool includes an electric motor having a motor shaft, an output shaft arranged in parallel to the motor shaft and configured to be driven by rotation of the motor shaft, a tool accessory operably connected to the output shaft and configured to undergo an orbital and/or rotational motion in response to rotation of the output shaft, a first bearing that rotatably supports the output shaft, and a second bearing that rotatably supports the output shaft and is arranged closer to the tool accessory than the first bearing in an axial direction in which the output shaft extends. The first and second bearings are arranged at positions that do not overlap with a radially outermost one of components of the electric motor when viewed in a shaft arrangement direction in which the motor shaft and the output shaft are arranged in parallel.

A floor polishing or grinding pad assembly is provided. In one aspect, a polishing or grinding pad assembly employs a fibrous pad, a reinforcement layer or ring, and multiple floor-contacting disks. In another aspect, the reinforcement layer includes a central hole through which the fibrous pad is accessible and the fibrous pad at the hole has a linear dimension greater than a linear dimension of one side of the adjacent reinforcement layer. In yet another aspect, at least one of the floor-contacting disks has an angle offset from that of a base surface of the disk, the fibrous pad and/or the reinforcement layer. A further aspect employs a smaller set of disks alternating between and/or offset from a larger set of the disks. In another aspect, the reinforcement layer includes a wavy or undulating internal edge shape.

A substrate polishing apparatus including a stage configured to load a substrate, the stage having a flat surface, which is parallel to a first direction and a second direction, and on which the substrate is loaded, a pressing unit configured to exert a pressure on the substrate in a third direction, a rotary unit configured to revolve the pressing unit around a central axis parallel to the third direction, when viewed in a plan view, a plurality of polishing pads provided between the pressing unit and the substrate to be in contact with the substrate, and a nozzle part configured to supply a slurry onto the substrate. The polishing pads may be spaced apart from each other in a direction and may have a rectangular shape in the plan view.

A floor polishing or grinding pad assembly is provided. In one aspect, a polishing or grinding pad assembly employs a fibrous pad, a reinforcement layer or ring, and multiple floor-contacting disks. In another aspect, the reinforcement layer includes a central hole through which the fibrous pad is accessible and the fibrous pad at the hole has a linear dimension greater than a linear dimension of one side of the adjacent reinforcement layer. In yet another aspect, at least one of the floor-contacting disks has an angle offset from that of a base surface of the disk, the fibrous pad and/or the reinforcement layer. A further aspect employs a smaller set of disks alternating between and/or offset from a larger set of the disks. In another aspect, the reinforcement layer includes a wavy or undulating internal edge shape.

A floor polishing or grinding pad assembly is provided. In one aspect, a polishing or grinding pad assembly employs a fibrous pad, a reinforcement layer or ring, and multiple floor-contacting disks. In another aspect, the reinforcement layer includes a central hole through which the fibrous pad is accessible and the fibrous pad at the hole has a linear dimension (x) greater than a linear dimension (y) of one side of the adjacent reinforcement layer. In yet another aspect, at least one of the floor-contacting disks has an angle () offset from that of a base surface of the disk, the fibrous pad and/or the reinforcement layer. A further aspect employs a smaller set of disks alternating between and/or offset from a larger set of the disks. In another aspect, the reinforcement layer includes a wavy or undulating internal edge shape.

A grinding apparatus includes a table that holds a workpiece, and a grinding unit including a grinding wheel mounted to a spindle. The grinding wheel has a grindstone formed by binding abrasive grains with a bonding agent. In addition, the grinding apparatus further includes: a supply unit that supplies grinding water to at least the grindstone when grinding the workpiece; and a light applying unit that is disposed adjacent to the table and that applies light to a grinding surface of the grindstone grinding the workpiece held by the table. The light applying unit includes a light emission section that emits light, and a diffusion preventive wall that surrounds the light emission section and prevents diffusion of the light.

Chemical mechanical polishing can be used for touch-up polishing in which polishing is performed on a limited area of the front surface of the substrate. The contact area between the polishing pad and the substrate can be substantially smaller than the radius surface of the substrate. During polishing, the polishing pad can undergo an orbital motion. The polishing pad can be maintained in a fixed angular orientation during the orbital motion. The contact area can be arc-shaped. The contact area can be provided by one or more lower portions projecting downward from an upper portion of the polishing pad. A perimeter portion of the polishing pad can be vertically fixed to an annular member and a remainder of the polishing pad within the perimeter portion can be vertically free.