A dresser includes: a mount component; and a cutting edge component inserted in the mount component at a base end portion side, wherein the portion of the cutting edge component inserted in the mount component has one or more portions in each of which an area of a cross section is increased from the front end portion side toward the base end portion side in the insertion direction, and a ratio L1/M1 of a length L1 and a maximum value M1 is more than or equal to 2.1, where L1 represents a length of the portion of the cutting edge component inserted in the mount component and M1 represents a maximum value of a diameter of a circle having an area equal to the area of the cross section of the portion of the cutting edge component inserted in the mount component.

In an X-ray topography image for a crystal growth main surface of a single-crystal diamond, a group of crystal defect points are gathered, each of the crystal defect points being a tip point of a crystal defect line reaching the crystal growth main surface, the crystal defect line representing a line in which a crystal defect exists. Further, in the single-crystal diamond, a plurality of crystal defect line-like gathered regions exist in parallel. In the plurality of crystal defect line-like gathered regions, groups of crystal defect points are gathered to extend in the form of lines in a direction angled by not more than 30 relative to one arbitrarily specified direction. Accordingly, a single-crystal diamond is provided which is used suitably for a cutting tool, a polishing tool, an optical component, an electronic component, a semiconductor material, and the like.

In an X-ray topography image for a crystal growth main surface of a single-crystal diamond, a group of crystal defect points are gathered, each of the crystal defect points being a tip point of a crystal defect line reaching the crystal growth main surface, the crystal defect line representing a line in which a crystal defect exists. Further, in the single-crystal diamond, a plurality of crystal defect line-like gathered regions exist in parallel. In the plurality of crystal defect line-like gathered regions, groups of crystal defect points are gathered to extend in the form of lines in a direction angled by not more than 30 relative to one arbitrarily specified direction. Accordingly, a single-crystal diamond is provided which is used suitably for a cutting tool, a polishing tool, an optical component, an electronic component, a semiconductor material, and the like.

The present application discloses a single-point diamond dresser for a grinding wheel based on acoustic emission online monitoring, which includes a support module, an anti-interference module, a compression cooling module and an acoustic emission online monitoring module. An acoustic emission sensor monitors the dressing state of the grinding wheel online; a damping sheet and a damping interlayer greatly reduce external noise interference; a high pressure coolant causes an upward elastic deformation of an elastic spacer and the damping sheet, enlarging a contact force between the acoustic emission sensor and the core and moreover improving a sensitivity of the acoustic emission sensor; the coolant flows through the coolant passages in the core to cool a dressing area; current limiting passages, pressure relief cavities and perforated pressure-relief plates limit flow and reduce a pressure of the coolant, reducing the interference of the coolant on the grinding wheel dressing.

The present application discloses a single-point diamond dresser for a grinding wheel based on acoustic emission online monitoring, which includes a support module, an anti-interference module, a compression cooling module and an acoustic emission online monitoring module. An acoustic emission sensor monitors the dressing state of the grinding wheel online; a damping sheet and a damping interlayer greatly reduce external noise interference; a high pressure coolant causes an upward elastic deformation of an elastic spacer and the damping sheet, enlarging a contact force between the acoustic emission sensor and the core and moreover improving a sensitivity of the acoustic emission sensor; the coolant flows through the coolant passages in the core to cool a dressing area; current limiting passages, pressure relief cavities and perforated pressure-relief plates limit flow and reduce a pressure of the coolant, reducing the interference of the coolant on the grinding wheel dressing.

The present diamond single crystal is a diamond single crystal containing nitrogen atoms, in which a concentration of the nitrogen atoms changes periodically along a crystal orientation of the diamond single crystal, and an arithmetic average value A.sub.ave, a maximum value A.sub.max, and a minimum value A.sub.min of the distance of one period along the crystal orientation satisfy the relationship expressed by the following equation (I):
(A.sub.max)/1.25(A.sub.ave)(A.sub.min)/0.75(I).

The present diamond single crystal is a diamond single crystal containing nitrogen atoms, in which a concentration of the nitrogen atoms changes periodically along a crystal orientation of the diamond single crystal, and an arithmetic average value A.sub.ave, a maximum value A.sub.max, and a minimum value A.sub.min of the distance of one period along the crystal orientation satisfy the relationship expressed by the following equation (I):
(A.sub.max)/1.25(A.sub.ave)(A.sub.min)/0.75(I).

A method of processing chemical mechanical polishing (CMP) pad conditioners includes providing the CMP pad conditioner including conditioner substrate that is a metal, ceramic or a metal-ceramic material with a plurality of hard conditioner particles with a Vickers hardness greater than 3,000 Kg/mm.sup.2 bonded to a top surface of the conditioner substrate, and a slurry including an aqueous medium and a plurality of hard slurry particles having a hardness greater than 3,000 Kg/mm.sup.2. The surface of the pad conditioner is polished in a CMP apparatus using a polishing pad. After the polishing each conditioner particle has at least one exposed facet, and the plurality of hard conditioner particles have a maximum average protrusion-to-protrusion flatness (PPF) difference of 20 microns, and a sharpest edge measured by a value of a cutting edge radius (CER) that lies at an edge of the facet for at least 80% of the facets.

A process for retruing a profile in an abrasive wheel is provided. A lathe table including an edged cutting tool is used for fixturing a grinding wheel having an outside metal edge and an abrasive matrix adjacent thereto for rotation along an axis compatible for lathe removal of material at at least the outside edge of said wheel. A predetermined amount of material along said edge with the edged lathe cutting tool is removed using the lathe cutting tool. A rotating electrical discharge profiling tool which is attached to an electrical discharge machine is used for profiling of the wheel by electrical discharge machining of the abrasive surface with the rotating electrode. The process uses a machine specifically designed for electrical discharge machining of the profile. The machine also has a mechanism cutting a predetermined profile into the electrode without removing it from the machine.

A process for retruing a profile in an abrasive wheel is provided. A lathe table including an edged cutting tool is used for fixturing a grinding wheel having an outside metal edge and an abrasive matrix adjacent thereto for rotation along an axis compatible for lathe removal of material at at least the outside edge of said wheel. A predetermined amount of material along said edge with the edged lathe cutting tool is removed using the lathe cutting tool. A rotating electrical discharge profiling tool which is attached to an electrical discharge machine is used for profiling of the wheel by electrical discharge machining of the abrasive surface with the rotating electrode. The process uses a machine specifically designed for electrical discharge machining of the profile. The machine also has a mechanism cutting a predetermined profile into the electrode without removing it from the machine.