The invention has a turnback roll which can transfer and guide a polishing tap in a tangential direction of a pressure contacting roll, a vertical oscillation mechanism which linearly oscillates the pressure contacting roll in a tangential direction of a ball groove while being orthogonal to a rotating axis line, and a horizontal oscillation mechanism which linearly oscillates the pressure contacting roll in a direction of a rotating axis line toward both inner side surfaces of the ball groove. The ball groove can be securely polished by the polishing tape on the basis of the continuous or intermittent transfer of the polishing tape and the linear oscillating motion of the ball groove. It is possible to improve a polishing precision, it is possible to improve a surface roughness of the ball groove and it is possible to improve a polishing workability of the ball groove.

A method of manufacturing an endodontic instrument includes providing a metal alloy powder and forming an endodontic instrument by depositing and heating successive layers of the metal alloy poser according to an additive manufacturing process. Forming an endodontic instrument according to an additive manufacturing process allows for advanced features such as one or more voids in the interior region of the instrument.

A grinding disc includes an inner layer (20) which is made of grindable material (containing abrasive particles) and an outer layer (20) which covers at least a portion of the surface of the inner layer (50) and which is made of non-grindable material (i.e. not-containing abrasive grain).

A method for producing a groove pattern on a cylinder surface includes providing an abrasive module, including an abrasive mesh article and collector block, providing a patterning head, which including the abrasive module and pressing actuator, pressing the abrasive module against the cylinder surface by using the actuator, forming a plurality of grooves on the cylinder surface by causing relative motion between the abrasive module and cylinder surface, and drawing gas through the abrasive mesh article to collect particles released from the cylinder surface. The abrasive mesh article includes a plurality of abrasive grains bonded to a flexible mesh backing, defining openings. The collector block has a curved supporting surface defining openings. The abrasive mesh article is attached to the curved supporting surface by a releasable fastening system. The openings of the flexible mesh backing are in communication with the openings of the collector block via the releasable fastening system.

A method for producing a groove pattern on a cylinder surface includes providing an abrasive module, including an abrasive mesh article and collector block, providing a patterning head, which including the abrasive module and pressing actuator, pressing the abrasive module against the cylinder surface by using the actuator, forming a plurality of grooves on the cylinder surface by causing relative motion between the abrasive module and cylinder surface, and drawing gas through the abrasive mesh article to collect particles released from the cylinder surface. The abrasive mesh article includes a plurality of abrasive grains bonded to a flexible mesh backing, defining openings. The collector block has a curved supporting surface defining openings. The abrasive mesh article is attached to the curved supporting surface by a releasable fastening system. The openings of the flexible mesh backing are in communication with the openings of the collector block via the releasable fastening system.

A cylindrical workpiece with a helical axial groove allowing for centerless grinding which has an angular overlap around the outer circumference on the body of the workpiece. The angular overlap ensures continuous tangential contact with the grinding wheels as the workpiece is rotated.

A method of processing a wafer includes: a grinding step of grinding a back surface of the wafer to form, on the back side of the wafer, a recess corresponding to a device region and an annular projecting portion corresponding to a peripheral marginal region; and a splitting groove forming step of forming, after the grinding step is conducted, a splitting groove for splitting the device region and the peripheral marginal region from each other at the boundary between the recess and the annular projecting portion, the splitting groove extending from the front surface of the wafer to reach the back surface of the wafer. The splitting groove is formed by dry etching.

A method of processing a wafer includes: a grinding step of grinding a back surface of the wafer to form, on the back side of the wafer, a recess corresponding to a device region and an annular projecting portion corresponding to a peripheral marginal region; and a splitting groove forming step of forming, after the grinding step is conducted, a splitting groove for splitting the device region and the peripheral marginal region from each other at the boundary between the recess and the annular projecting portion, the splitting groove extending from the front surface of the wafer to reach the back surface of the wafer. The splitting groove is formed by dry etching.

Disclosed herein is an apparatus for processing a substrate that forms a hole in a substrate while reducing a burr in the hole so that a module device can be inserted into the hole to reduce the thickness of a display device, and the display device using the apparatus. The apparatus for processing the substrate comprises a body configured to operably be rotatable, and a cylindrical cutting tip at an end of the body. The bottom surface of the cutting tip is in an acute angle with respect to a contact surface of the substrate to allow formation of a groove at the substrate.

Disclosed herein is an apparatus for processing a substrate that forms a hole in a substrate while reducing a burr in the hole so that a module device can be inserted into the hole to reduce the thickness of a display device, and the display device using the apparatus. The apparatus for processing the substrate comprises a body configured to operably be rotatable, and a cylindrical cutting tip at an end of the body. The bottom surface of the cutting tip is in an acute angle with respect to a contact surface of the substrate to allow formation of a groove at the substrate.