The technical objective of the present invention is to provide a cutting insert that can minimize a phenomenon in which the cutting insert is lifted up from a seat surface of a cutting tool while a cutting process is being performed, and can increase an area by which the cutting insert is fastened to the cutting tool. To this end, the cutting insert of the present invention comprises: a principal surface; a fastening surface opposite to the principal surface, the fastening surface being placed on the seat surface of the cutting tool; and a screw passage hole formed through each of central portions of the principal and fastening surfaces, wherein a screw is fastened to the cutting tool through the screw passage hole; and first and second long grooves extending across the fastening surface, wherein each of the first and second long grooves includes: a proximal sidewall adjoining a first adjacent fastening portion of the fastening surface and making an acute angle with the first adjacent fastening portion; a distal sidewall adjoining a second adjacent fastening portion of the fastening surface and making an angle with the second adjacent fastening portion; and a ceiling wall connecting the proximal and distal sidewalls, wherein the proximal sidewall is located closer to the screw passage hole than the distal sidewall is located to the screw passage hole.

The invention is a monolithic end-mill cutter set (A) that can be made of ceramic and/or other materials having high strength and toughness and comprising a shank part (B) along a longitudinal axis (4) and a cutter part (C), comprising: a cutting diameter (1) varying between 2 to 20 mm, at least one web thickness (18) found at a blade (26) part, at least one helix angle (10) having a cutting edge (13) thereon, a core diameter (16) that is at least 0.7 times the cutting diameter (1), at least one corner radius (5) found at the tip part of the blades (26) between the flutes (9) and axial and positive radial rake angles (17) at which cutting operation is made. It has a wide helix angle interval and a positive rake angle. Titanium Aluminum Nitride TiAlN coating can be made on the monolithic end-mill cutter set (A) via PVD coating method in order to extend the service life of the end-mill cutter set (A), increase the abrasion resistance, and minimize the problem of sticking of rake on the cutter set (joining).

Square end mill includes long end cutting edge disposed from end portion on outer peripheral side in radial direction to center in the radial direction when a cutting edge portion is viewed from end face side, and short end cutting edges disposed from other end portions on outer peripheral side in radial direction to middles on center side in radial direction, first gashes disposed on regions from lines connecting end portions on center side in radial direction of the short end cutting edges to center in radial direction to the long end cutting edge on rear side in the rotation direction, second and third gashes disposed on rear and front sides in rotation direction of the first gashes, and all gashes formed in curved surface shapes depressed to a shank side on opposite side in axial direction of the cutting edge portion.

An indexable cutting insert has opposing upper and lower end surfaces, and a peripheral surface including three side surfaces circumferentially alternating with three corner surfaces. The three side surfaces define an imaginary triangle and an imaginary hexagon. Each corner surface intersects the upper end surface to form an upper corner peripheral edge having a primary cutting edge. In a top view, each triangle side traverses two upper corner peripheral edges, imaginary lines tangential to the end points of each primary cutting edge are either collinear or form an obtuse angle greater than 175 degrees, each primary cutting edge has a primary length greater than half the hexagon side length, and at least one triangle side traverses each primary cutting edge. The insert is removably secured in a rotary cutting tool such that one of the upper corner peripheral edges contains an axially forwardmost point of the insert's upper peripheral edge.

A tool for machining a stacked material workpiece includes a tool body having one or more helical flutes extending to a forward end of the tool body. Each helical flute has a width defined by a first cutting edge and a second edge, a surface of the flute adjacent the first cutting edge facing the forward end of the tool body and a surface of the flute adjacent the second edge facing away from the forward end of the tool body. Each helical flute can include a first portion having a first negative pitch angle and a second portion having a second negative pitch angle different from the first negative pitch angle, the first portion extending from the forward end of the tool body to the second portion. The tool has only negative pitch angles. A method for machining a stacked material is also disclosed.

A reusing method of an end mill 1, in which an end mill (1) has a margin which is a part of a circle having a diameter identical to a diameter of a shank part (3), the margin being provided on an outer edge of a cutting part (2), a base material of the end mill (1) is machined in advance so as to have coaxiality having equal accuracy to coaxiality for the cutting part (2), the shank part (3) is an unmachined part left without cutting the base material, the margin is a part of an outer peripheral surface of the base material left without cutting the base material when the outer edge is formed by cutting the base material, and when the cutting part (2) is worn out, the cutting part (2) is cut off and a new cutting part 2 is machined on the shank part (3) while a part of outer peripheral surface of the shank part is left as the margin without cutting, the new cutting part 2 having accuracy of coaxiality and an outer diameter identical to those of the cutting part (2).

A end mill includes: an end mill body having a rotation axis, the end mill body including a shank portion and a cutting portion with an outer peripheral cutting edge; an end cutting edge including a first cutting edge and a second cutting edge; a first gash opening between the first cutting edge and the second cutting edge; and a second gash located adjacently to the first gash in the rotational direction, and opening to a side closer to the outside peripheral from the chisel portion. A ratio (L1/L2) of a length (L1) from a distal end of the end mill body to a terminal end of the first gash to a length (L2) from the distal end of the end mill body to a terminal end of the second gash, when viewed from a side, is from 0.8 to 1.1.

The present invention provides a cutting insert in which suitable honing is formed on a cutting edge. The cutting insert is provided with: two end surfaces opposing each other; a peripheral side surface extending between the two end surfaces; and a cutting edge formed on an intersecting ridge between at least one of the two end surfaces and the peripheral side surface. The cutting edge at least includes a major cutting edge and an inner cutting edge. Honing is provided on the major cutting edge and the inner cutting edge. A width of second honing of the inner cutting edge is narrower than a width of first honing of the major cutting edge, as viewed from a side of the end surfaces.

A milling tool is suggested having a base body (3), a central axis (M), and a front side (5), whereby at least two geometrically defined first front edges (9) that are arranged, respectively, at front side (5) of base body (3) exhibit a first edge section (13) facing central axis (M).

Milling tool (1) distinguishes itself by the first edge sections (13) of the at least two front edges (9) being formed in an ascending fashion towards center axis (M), so that they form a centering tip (15), and that centering tip (15) is arranged in a recessed manner in an axial direction when compared with an axial outermost point (17) of at least two of the first front edges (9).

The technical objective of the present invention is to provide a cutting insert that can minimize a phenomenon in which the cutting insert is lifted up from a seat surface of a cutting tool while a cutting process is being performed, and can increase an area by which the cutting insert is fastened to the cutting tool. To this end, the cutting insert of the present invention comprises: a principal surface; a fastening surface opposite to the principal surface, the fastening surface being placed on the seat surface of the cutting tool; and a screw passage hole formed through each of central portions of the principal and fastening surfaces, wherein a screw is fastened to the cutting tool through the screw passage hole; and first and second long grooves extending across the fastening surface, wherein each of the first and second long grooves includes: a proximal sidewall adjoining a first adjacent fastening portion of the fastening surface and making an acute angle with the first adjacent fastening portion; a distal sidewall adjoining a second adjacent fastening portion of the fastening surface and making an angle with the second adjacent fastening portion; and a ceiling wall connecting the proximal and distal sidewalls, wherein the proximal sidewall is located closer to the screw passage hole than the distal sidewall is located to the screw passage hole.