A silicon carbide ingot includes an end surface and an end surface opposite to the end surface. In the silicon carbide ingot, the end surface and the end surface face each other in a growth direction, and a gradient of a nitrogen concentration in the growth direction is not less than 110.sup.16 cm.sup.4 and not more than 110.sup.18 cm.sup.4.

A metal wire containing tungsten is provided. A tungsten content of the metal wire is at least 90 wt %. A tensile strength of the metal wire is at least 4000 MPa. An elastic modulus of the metal wire is at least 350 GPa and at most 450 GPa. A diameter of the metal wire is at most 60 m. An average crystal grain size of the metal wire in a cross-section orthogonal to an axis of the metal wire is at most 0.20 m.

Method for slicing a workpiece, including measuring a crystal axis orientation while holding a workpiece with a workpiece holder, setting the workpiece holder to a wire saw in such a manner that the measured crystal axis orientation is maintained, then adjusting a sliced plane orientation, pressing the workpiece against a wire row to slice the workpiece; the workpiece holder includes a portion slidable while holding the workpiece and a portion for fixing the slide portion, after measuring the crystal axis orientation, sliding the slide portion to move to the workpiece holder center in a manner that the measured crystal axis orientation is maintained, fixing the slide portion, setting the workpiece holder to the wire saw, then adjusting the sliced plane orientation, and slicing the workpiece. This enables an orientation measurement without limitation of distance between an orientation measuring instrument and plane to be measured can inhibit warpage deterioration and workpiece breakage.

A method for manufacturing a wire saw apparatus including a wire supply reel; a long roller; wire guides; a wire winding reel; and a tension arm controlled to move within a control angle of ?A (?) set in advance and configured to apply tension to the wire, the method including the steps of: measuring a surface roughness Rmax of the long roller; measuring an angle a (?) of the tension arm at which the tension arm swings outside a range of the control angle set in advance while the wire is extending from the wire supply reel; calculating R1?2?A?(|a|+A)=R2, where R1 (?m) represents the measured surface roughness Rmax of the long roller; and adjusting the surface roughness Rmax of the long roller to the calculated numerical value R2 or less. The method for manufacturing a wire saw apparatus can prevent the tension arm from greatly swinging outside the control range.

A wire guide roll for use in wire saws for simultaneously slicing a multiplicity of wafers from a cylindrical workpiece is provided with a coating having a thickness of at least 2 mm and at most 7.5 mm of a material which has a Shore A hardness of at least 60 and at most 99, and which contains a multiplicity of grooves through which the sawing wire is guided, the grooves each having a curved groove base with a radius of curvature which is 0.25-1.6 times the sawing wire diameter, and an aperture angle of 60-130. A multiplicity of wafers are simultaneously sliced from a cylindrical workpiece by a wire saw using such wire guide rolls.

An abrasive article comprising a substrate having an elongated body and abrasive particles attached to the elongated body, the content of the abrasive particles oscillates along the length of the body between a minimum and maximum value, and the minimum content is greater than 0.

A three-dimensional object manufacturing method for manufacturing a three-dimensional object by ejecting a liquid shaping material and then solidifying the ejected shaping material includes: an interior forming process of forming an interior portion of the three-dimensional object by the shaping material; and a periphery forming process of forming a peripheral portion of a periphery of the interior portion by stacking a plurality of layers by the shaping material, where the shaping material for forming the interior portion in the interior forming process has a larger rigidity in a solid state compared to the shaping material for forming the peripheral portion in the periphery forming process, the periphery forming process is a process of forming a groove configuring one part of the peripheral portion, and the interior forming process is a process of forming the interior portion by placing the liquid shaping material in the groove.

The present invention is a method for slicing a workpiece, including: forming a wire row by a wire spirally wound between a plurality of wire guides and traveling in an axial direction, and pressing a workpiece against the wire row while supplying a processing liquid containing abrasive grains to a contact portion between the workpiece and the wire, wherein a used portion of the abrasive grains are subjected to a treatment with a mixed liquid of sulfuric acid and hydrogen peroxide, and the abrasive grains subjected to the treatment are reused for the slicing of a workpiece. This makes it possible to slice a workpiece with suppressing contamination of a wafer with metal impurities when abrasive grains are reused in slicing a workpiece by use of a wire saw.

In order to respond flexibly to various processing modes, such as forming curved surface shapes, when cutting a workpiece using a wire saw, this wire saw device (1) is provided with: a single robot arm (2) that is capable of moving freely by means of multi-axis control; a wire saw unit (3) that is detachably connected to the robot arm (2) via a tool changer (7); a wire (8) that spans a plurality of pulleys supported within the wire saw unit (3); and a workpiece cutting zone (20) that is established between the pulleys. The workpiece is cut to a prescribed shape by moving the robot arm (2) in a preset direction while running the wire (8) of the wire saw unit (3) and pressing the wire (8) against the supported workpiece.

A wire (12) is wound around multiple processing rollers (11) several times. A holding mechanism (13) and a depressing mechanism (25) are provided above an area where the wire (12) is wound. The holding mechanism (13) holds a workpiece (W) elastically and laterally. The depressing mechanism (25) depresses the workpiece (W) held by the holding mechanism (13) toward the wire (12).