An origin determination method includes the steps of adjusting a positional relation between a chuck table and a grinding unit by a moving mechanism such that lower ends of grinding stones and a holding surface are brought apart along a moving direction, moving the chuck table and the grinding unit relative to each other by the moving mechanism such that the lower ends of the grinding stones and the holding surface are brought closer to each other by a predetermined distance, and determining whether a measurement value of a load applied to the holding surface has reached a threshold. If the measurement value is determined to have reached the threshold, a positional relation between the chuck table and the grinding unit at that time is determined to be an origin of the moving mechanism. Otherwise, the step of moving and the step of determining are then performed again.

A management method of a machining system includes a chuck table, a machining unit, a transfer unit that transfers a wafer onto the chuck table, a camera unit that acquires an image containing a pattern formed on a side of a front surface of the wafer, and an information recording section. The management method is applied when the pattern is recorded in association with machining conditions in the information recording section; and records in the information recording section new machining conditions to be used when machining a new type of wafer, causes an automatic machining program, which automatically machines the new type of wafer, to start, forms an image, which contains a new pattern of the new type of wafer, by the camera unit, and records the new pattern in association with the new machining conditions in the information recording section.

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).

The invention provides an electrochemical discharge-assisted micro-grinding device for micro-components of brittle and hard materials. The device includes a micro-grinding tool, grinding fluid, a workpiece, an auxiliary electrode, a processing groove, and a pulsed DC power supply; the processing groove is filled with grinding fluid; the micro-grinding tool, the workpiece, and the auxiliary electrode are immersed in the grinding fluid; the micro-grinding tool is composed of a conductive grinding tool base, an electroplating layer, and insulated superabrasives. The micro-grinding tool is connected to the negative electrode of the pulsed DC power supply; the grinding fluid is composed of H.sub.2O.sub.2, Na.sub.2CO.sub.3, EDTA-Fe-Na, and deionized water; the workpiece material is brittle and hard; a large number of micro structures need to be produced on the surface of the workpiece.

Provided is a means capable of sufficiently removing residues on a surface of an object to be polished while polishing the object to be polished at a moderate speed.

Provided is a polishing composition containing: anionically-modified colloidal silica; a dispersing medium; an anionic water-soluble polymer which is a copolymer including a structural unit having a sulfonic acid group or a salt group thereof and a structural unit having a carboxy group or a salt group thereof; a polypropylene glycol having a weight average molecular weight of 200 or more and 700 or less; a nitrogen-free non-ionic polymer other than the polypropylene glycol having a weight average molecular weight of 200 or more and 700 or less; and a nitrogen-containing non-ionic polymer.

A grinding apparatus and a grinding method of a composite substrate including resin, by which loading of a grinding wheel can be suppressed in grinding of a large-sized composite substrate including resin, and with which grinding can be effectively performed with high precision. This method for grinding a front surface of a composite substrate formed with a resin substrate embedded with at least one of a semiconductor device chip and an electrode, includes: bringing at least a part of a grinding member for grinding the front surface of the composite substrate into contact with the front surface; supplying water to at least one of a contacting part or a non-contacting part between the front surface of the composite substrate and the grinding member; and grinding the front surface of the composite substrate simultaneously with the supplying water.

A grinding and/or polishing machine (10) for slabs of stone material, such as natural or agglomerated stone, ceramic or glass, comprises a support bench (12) for the slabs to be machined and at least one machining station (14) with a pair of bridge-like support structures (16, 18) arranged opposite each other with, above, a beam supporting a plurality of machining spindles (26). First relative movement means (19) move the slab in a longitudinal direction with respect to the machining station (14), while the beam moves transversely with respect to its length by means of second movement means (21). Each spindle is supported on the beam so that it can be swivelled by associated movement means (34, 35, 40, 50, 60) about an oscillation axis (33) which is parallel to, but separate from the motorized vertical axis (32) of the spindle. The spindles thus oscillate about the respective oscillation axes (33) in cooperation with the longitudinal and transverse movements, respectively, of the first and second movement means (19 and 21) so as to polish and/or grind the surface of a slab on the support bench.

A grinding apparatus includes a chuck table that holds a wafer on a holding surface; a grinding unit that has a spindle unit in which a spindle with an annular grindstone mounted to a tip thereof is rotatably supported and that grinds the wafer by use of the grindstone; a grinding feeding mechanism that puts the grinding unit into grinding feeding in a grinding feeding direction perpendicular to the holding surface; a first height gauge that measures the height of the holding surface; a second height gauge that measures the height of an upper surface of the wafer; and a calculation section that calculates the difference between the height of the holding surface and the height of the upper surface of the wafer, as the thickness of the wafer. In the grinding apparatus, the first height gauge and the second height gauge are disposed in the grinding unit.

Described is a tool-holder cylinder (100; 300) for supporting abrasive tools, designed to be attached to a head (71) of a machine tool for surface machining of ceramic and/or stone materials, wherein said head (71) is configured to rotate about a first axis (x) substantially parallel to a surface to be machined and coinciding with the axis of central symmetry of said cylinder (100; 300), said cylinder (100; 300) comprising an upper surface (120; 320), a lower surface (130; 330), and a side surface (160; 360) parallel to the first axis (x) and on which are formed a plurality of seats (111; 311) designed to house said abrasive tools by means of a dovetail coupling, characterised in that said seats (111; 311) have a first tapering which extends perpendicularly and away from the first axis (x), and a second tapering parallel to the first axis (x). The invention further relates to an abrasive unit comprising a cylinder of the said type and to a machine comprising said abrasive unit.