Emerald-cut diamond with length/width of 1.35 to 1.40; table of 55 to 60 percent; corner ratio of 13.5 to 14.5 percent; girdle thickness up to 3 percent; crown main angle of 28 to 45 degrees; first crown break angle of 2 to 6 degrees; second crown break angle of 2 to 6 degrees; pavilion main angle of 43 to 48 degrees; first pavilion break angle of 2 to 5 degrees; and second pavilion break angle of 2 to 5 degrees. Diamonds cut in accordance with these parameters may have light performance 0-grade domains on a grade map with wide crown and pavilion mains ranges. A method cuts the diamond according to the parameters, and may include selecting crown and pavilion main angles from the map, and cutting the diamond sufficiently close to the selected cutting parameters to obtain the light performance grade of 0.

A polishing fixture and a polishing system are disclosed. The polishing fixture includes a supporting platform, and an operating platform detachably and fixedly connected to the supporting platform. The operating platform includes at least two locating pins, the supporting platform and the operating platform are fixedly connected together to form a placement platform for the product to be polished. The object of the present invention is to provide a polishing fixture and a polishing system, after hundreds of products are fixed by the polishing fixture, the polishing equipment is capable of polishing hundreds of products at one time, which improves the polishing efficiency and reduce the rejection rate of the polishing products at the same time, and the rejection rate is as low as about three per thousand.

A method for producing a rotor of a screw compressor or a workpiece with a helical profile, the rotor or the workpiece with a helical profile having a number of profiles in the form of groove-shaped recesses running in a spiral manner on the outer periphery thereof, the groove-shaped recesses being fine-machined using a grinding tool for the purpose of generating a precise profile. To be able to produce rotors and workpieces having variable pitch along the axial extent of the rotor or the workpiece as precisely as possible, the groove-shaped recesses are fine-machined with a grinding tool which only touches the surface of the groove-shaped recess at one point during the grinding process. The entire surface to be machined is machined by the grinding tool through line-by-line traversing of the surface to be machined.

A processing apparatus includes a chuck table having a holding surface for holding a plate-shaped workpiece thereon, a processing unit for processing the plate-shaped workpiece held on the chuck table, a delivery unit for selectively delivering the plate-shaped workpiece onto and from the chuck table, and a control unit for controlling the chuck table, the processing unit, and the delivery unit. The chuck table includes a gas ejection port defined in or around the holding surface and connected to a gas supply system. While the plate-shaped workpiece is not placed on the holding surface, the control unit controls the gas supply system to eject a gas from the gas ejection port to form a protective layer of the gas over the holding surface, thereby preventing foreign matter from being deposited on the holding surface.

A processing apparatus includes a chuck table having a holding surface for holding a plate-shaped workpiece thereon, a processing unit for processing the plate-shaped workpiece held on the chuck table, a delivery unit for selectively delivering the plate-shaped workpiece onto and from the chuck table, and a control unit for controlling the chuck table, the processing unit, and the delivery unit. The chuck table includes a gas ejection port defined in or around the holding surface and connected to a gas supply system. While the plate-shaped workpiece is not placed on the holding surface, the control unit controls the gas supply system to eject a gas from the gas ejection port to form a protective layer of the gas over the holding surface, thereby preventing foreign matter from being deposited on the holding surface.

A wafer producing apparatus detects a facet area from an upper surface of an SiC ingot, sets X and Y coordinates of plural points lying on a boundary between the facet area and a nonfacet area in an XY plane, and sets a focal point of a laser beam having a transmission wavelength to SiC inside the SiC ingot at a predetermined depth from the upper surface of the SiC ingot. The predetermined depth corresponds to the thickness of the SiC wafer to be produced. A control unit increases the energy of the laser beam and raises a position of the focal point in applying the laser beam to the facet area as compared with the energy of the laser beam and a position of the focal point in applying the laser beam to the nonfacet area, according to the X and Y coordinates.

A wafer producing apparatus detects a facet area from an upper surface of an SiC ingot, sets X and Y coordinates of plural points lying on a boundary between the facet area and a nonfacet area in an XY plane, and sets a focal point of a laser beam having a transmission wavelength to SiC inside the SiC ingot at a predetermined depth from the upper surface of the SiC ingot. The predetermined depth corresponds to the thickness of the SiC wafer to be produced. A control unit increases the energy of the laser beam and raises a position of the focal point in applying the laser beam to the facet area as compared with the energy of the laser beam and a position of the focal point in applying the laser beam to the nonfacet area, according to the X and Y coordinates.

Systems and methods for treating concrete, which includes the steps of wetting a surface of concrete with colloidal silica, allowing time for the colloidal silica to penetrate the concrete surface, and cutting the surface of the concrete with a bladed or segmented tool wherein the longitudinal blade or edge portion is positioned approximately at an angle between 30 degrees and 90 degrees relative to the surface of the concrete.

Systems and methods for treating concrete, which includes the steps of wetting a surface of concrete with colloidal silica, allowing time for the colloidal silica to penetrate the concrete surface, and cutting the surface of the concrete with a bladed or segmented tool wherein the longitudinal blade or edge portion is positioned approximately at an angle between 30 degrees and 90 degrees relative to the surface of the concrete.

A method of processing a plate-shaped workpiece is provided. The method includes the steps of sticking a protective member to a face side of the workpiece, holding the face side of the workpiece on a holding surface of a chuck table with the protective member interposed therebetween, grinding a reverse side of the workpiece held on the chuck table to thin the workpiece by rotating a grinding wheel including grinding stones that contain abrasive grains, while a grinding fluid is being supplied from a grinding fluid supply nozzle to the reverse side of the workpiece, and after the step of grinding the reverse side of the workpiece, treating the workpiece or the grinding stones by rotating the grinding wheel and bringing the grinding stones into contact with the reverse side of the workpiece, while stopping supplying the grinding fluid from the grinding fluid supply nozzle.