A space-saving centerless grinding machine having high operability is obtained by devising the configuration of component units around the basic configuration of the machine. A dressing means for performing a dressing process for a grinding wheel and a regulating wheel comprises a single dressing unit. The dressing unit is located at a lower position between the grinding wheel and the regulating wheel, and thus eliminates the need for right and left dresser spaces for grinding wheels that have most seriously affected the breadthwise dimension of a conventional centerless grinding machine, leading to space saving and a considerable reduction in the breadthwise dimension of the centerless grinding machine.

A space-saving centerless grinding machine having high operability is obtained by devising the configuration of component units around the basic configuration of the machine. A dressing means for performing a dressing process for a grinding wheel and a regulating wheel comprises a single dressing unit. The dressing unit is located at a lower position between the grinding wheel and the regulating wheel, and thus eliminates the need for right and left dresser spaces for grinding wheels that have most seriously affected the breadthwise dimension of a conventional centerless grinding machine, leading to space saving and a considerable reduction in the breadthwise dimension of the centerless grinding machine.

The present disclosure relates to a dressing tool. The dressing tool can include a shank having a proximal end and a distal end as well as an abrasive tip. The abrasive tip may include a superabrasive material that may be bonded to the distal end of the shank. The abrasive tip may be tilted relative to a longitudinal axis of the shank.

The present disclosure relates to a dressing tool. The dressing tool can include a shank having a proximal end and a distal end as well as an abrasive tip. The abrasive tip may include a superabrasive material that may be bonded to the distal end of the shank. The abrasive tip may be tilted relative to a longitudinal axis of the shank.

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).

Diamond-containing articles such as composite materials shaped as some specific article, can be engineered such that bodies that contact the article only contact diamond. In an embodiment, the article may be in the form of equipment for handling semiconductor wafers such as vacuum or electrostatic chucks. In one embodiment, the diamond-containing article can be a composite of diamond particulate reinforcing a Si/SiC body such as reaction-bonded SiC. Lapping the diamond-reinforced RBSC body with progressively finer diamond grit removes some of the SiC/Si matrix material, leaving diamond particles of uniform height standing proud above the rest of the surface of the formed article. Further, if the diamond-containing article is sufficiently electrically conductive, it may be machinable using electrical discharge machining.

Diamond-containing articles such as composite materials shaped as some specific article, can be engineered such that bodies that contact the article only contact diamond. In an embodiment, the article may be in the form of equipment for handling semiconductor wafers such as vacuum or electrostatic chucks. In one embodiment, the diamond-containing article can be a composite of diamond particulate reinforcing a Si/SiC body such as reaction-bonded SiC. Lapping the diamond-reinforced RBSC body with progressively finer diamond grit removes some of the SiC/Si matrix material, leaving diamond particles of uniform height standing proud above the rest of the surface of the formed article. Further, if the diamond-containing article is sufficiently electrically conductive, it may be machinable using electrical discharge machining.

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.

A space-saving centerless grinding machine having high operability is obtained by devising the configuration of component units around the basic configuration of the machine. A dressing means for performing a dressing process for a grinding wheel and a regulating wheel comprises a single dressing unit. The dressing unit is located at a lower position between the grinding wheel and the regulating wheel, and thus eliminates the need for right and left dresser spaces for grinding wheels that have most seriously affected the breadthwise dimension of a conventional centerless grinding machine, leading to space saving and a considerable reduction in the breadthwise dimension of the centerless grinding machine.