When forming a first preliminary flute on a PCD layer of a columnar body, electrical discharge machining is performed by setting the electrode orientation so that the first twist angle is α. Next, when forming a second preliminary flute on a substrate of the columnar body and a round bar, the grinding process is performed by setting the grinding orientation and direction for a diamond whetstone so that a second twist angle is larger than the first twist angle.

A drill bit for a drill includes a body clearance extending helically along the drill bit, a margin also extending helically along the drill bit, adjacent to and projecting radially beyond the body clearance, and a flank at which the body clearance and the margin terminate at a tip of the drill bit. The margin has a variable width along its helical extension.

A method of making a cutting tap includes: providing an elongate tap body having an axial forward end, an axial rearward end and a central longitudinal axis; securing the axial rearward end of the tap body in a grinding machine; and forming in the axial forward end of the tap body a correction grind and a main flute in one continuous grinding operation. A cutting tap made by the invention is also provided.

A method of making a cutting tap includes: providing an elongate tap body having an axial forward end, an axial rearward end and a central longitudinal axis; securing the axial rearward end of the tap body in a grinding machine; and forming in the axial forward end of the tap body a correction grind and a main flute in one continuous grinding operation. A cutting tap made by the invention is also provided.

The invention describes an apparatus (1) for a cutting edge preparation of cutting tools (5), in particular of drills or milling tools or similar tools (5), in particular of hard-metal cutting tools, wherein during a relative movement the cutting tool (5) interacts in a machining fashion with a flexibly-bonded grinding body (2) that is provided with abrasive particles, the particles of the grinding body (2) influencing the edge geometry of the cutting tool (5),

wherein the grinding body (2) is adapted with its dimensions substantially to the dimensions of the respective cutting tool (5) that is to be prepared and is accommodated in an exchangeable holder (4) which is arranged in a region of a processing device, in particular of a tool grinding machine, and is held such that it is machinable by the cutting tool (5) for the cutting edge preparation. Furthermore, a corresponding method and a corresponding grinding body (2) are given.

The invention describes an apparatus (1) for a cutting edge preparation of cutting tools (5), in particular of drills or milling tools or similar tools (5), in particular of hard-metal cutting tools, wherein during a relative movement the cutting tool (5) interacts in a machining fashion with a flexibly-bonded grinding body (2) that is provided with abrasive particles, the particles of the grinding body (2) influencing the edge geometry of the cutting tool (5),

wherein the grinding body (2) is adapted with its dimensions substantially to the dimensions of the respective cutting tool (5) that is to be prepared and is accommodated in an exchangeable holder (4) which is arranged in a region of a processing device, in particular of a tool grinding machine, and is held such that it is machinable by the cutting tool (5) for the cutting edge preparation. Furthermore, a corresponding method and a corresponding grinding body (2) are given.

Systems and methods include a computer-implemented method can be used to make drilling tools from new wurtzite boron nitride (w-BN) superhard material. An ultra-high-pressure, high-temperature operation is performed on pure w-BN powder to synthesize w-BN and cubic boron nitride (c-BN) compact having a first size greater than particles of the pure w-BN powder. The ultra-high-pressure, high-temperature operation includes pressurizing the w-BN powder to a pressure of approximately 20 Gigapascal, heating the w-BN powder at a heating rate of 100° C./minute and cooling the w-BN powder at a cooling rate of 50° C./minute. The compact is cut to a second size smaller than the first size using laser cutting tools. The cut compact is bonded metallurgically, mechanically, or both metallurgically and mechanically onto a tool substrate to form the drilling tool.

Systems and methods include a computer-implemented method can be used to make drilling tools from new wurtzite boron nitride (w-BN) superhard material. An ultra-high-pressure, high-temperature operation is performed on pure w-BN powder to synthesize w-BN and cubic boron nitride (c-BN) compact having a first size greater than particles of the pure w-BN powder. The ultra-high-pressure, high-temperature operation includes pressurizing the w-BN powder to a pressure of approximately 20 Gigapascal, heating the w-BN powder at a heating rate of 100° C./minute and cooling the w-BN powder at a cooling rate of 50° C./minute. The compact is cut to a second size smaller than the first size using laser cutting tools. The cut compact is bonded metallurgically, mechanically, or both metallurgically and mechanically onto a tool substrate to form the drilling tool.

A method of producing a drill has a step of preparing a workpiece to be processed to produce a drill, and a step of forming a ground groove. The workpiece has a cutting blade, a chip discharge flute helically extending, and a rake surface which have been formed therein. The drill is rotated around a drill axial center. The formation step rotates a rotary whetstone around its whetstone axial center, and grinds the rake surface to form the ground groove along the chip discharge flute. The formation step uses the rotary whetstone so that the whetstone axial center intersects a longitudinal direction of the chip discharge flute. The rotary whetstone has a rotating body shape projecting in a radial outward direction of the rotary whetstone axial center and around the rotary whetstone axial center.

An end mill for milling composite materials, for example, fiber-reinforced plastics, having a defined rotating direction, a shank and a cutting part that extends from a shank-side end up to a frontal end and in a front length region adjoining the frontal end of the cutting part, has a plurality of first circumferential cutters running with a positive helix angle, each of which adjoins a first groove running with a positive helix angle, and in a rear length region adjoining the shank-side end of the cutting part, has a plurality of second circumferential cutters running with a negative helix angle, each of which adjoins a second groove running with a negative helix angle. At least a part of the first circumferential cutters in the front length region, and at least a part of the second circumferential cutters in the rear length region, are each divided into cutting segments.