A rotary cutting tool that implements a chip space in proportion to a feed-per-tooth is proposed. The rotary cutting tool includes a cutting part in which a plurality of cutting teeth and flutes are alternately formed, wherein a cross-section of the cutting part perpendicular to a central axis is divided into a plurality of cutting tooth spaces defining a section between cutting edges of adjacent cutting teeth on the basis of the central axis, such that all of the cutting tooth spaces are designed in different sizes, or some of the plurality of cutting tooth spaces are set in different sizes from the other cutting tooth spaces.

A milling cutter having a shank and a cutting head attached to the shank. The cutting head has a plurality of helical teeth, each tooth including a cutting tip, a leading face and a rear face. A flute is defined between the leading face of a trailing tooth, and a rear face of an immediately preceding tooth. A gully of the flute is generally W-shaped in cross section to provide effective chip evacuation. A method for manufacturing the milling cutter with the W-shaped gully of the flute using a split path grinding process is also disclosed.

A milling tool having a front end, a rear end, a longitudinal axis extending therebetween, a shank portion and a cutting portion. The cutting portion includes a plurality of teeth separated by a corresponding number of flutes. Each tooth extends axially along the cutting portion following a curved helical path around the longitudinal axis, and extends at a first helix angle from the front end to a helix transition, and at a second helix angle from the helix transition towards the shank portion. The second helix angle is greater than the first helix angle by at least 2° and at most 15°. The first helix angle (α) is 33°≤α≤50°, and the second helix angle (β) is 40°≤β≤55°, and wherein the helix transition is axially located from the front end by 0.2 to 0.7 of the longitudinal length of the cutting portion.

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.

An electrodynamic acoustic transducer (1) is disclosed, which comprises a frame and/or a housing (2), a membrane (3), a magnet system (6) with a plurality of center magnets (7a . . . 7d, 7, 7′) having different magnetic orientations (M.sub.1 . . . M.sub.4) and a coil arrangement (10) with a plurality of voice coils (11a . . . 11d), which are movably arranged relative to the magnet system (6) in an excursion direction (z). The ratio

[00001]$\frac{A_g.Math.h_m}{A_m.Math.w_g}=\frac{l_g.Math.h_{\mathrm{tp}}.Math.h_m}{A_m.Math.w_g}$

is below 1, wherein w.sub.g denotes the mean width of all airgaps (E) within the magnet system (6), A.sub.g denotes the sum of all airgap areas within the magnet system (6), h.sub.m denotes the mean height of the center magnets (7a . . . 7d, 7, 7′) and A.sub.m denotes the total area of the center magnets (7a . . . 7d, 7, 7′). Moreover, the invention relates to an electroacoustic system (19), which comprises an electrodynamic acoustic transducer (1) of the above kind and a control circuit (CC) connected to the coil arrangement (10).

A milling cutter includes a shank and a cutting head attached to the shank. The cutting head has a plurality of helical teeth, each tooth including a cutting tip, a leading face and a rear face. A flute is defined between the leading face of a trailing tooth, and a rear face of an immediately preceding tooth. A gully of the flute is generally W-shaped in cross section to provide effective chip evacuation. A method for manufacturing the milling cutter with the W-shaped gully of the flute using a split path grinding process is also disclosed.

A corner radius end mill includes a blended gash extending along a cutting edge. The blended gash is formed in a corner sector of the end mill. The corner sector has a first half-sector and a second half-sector defined on opposite sides of an imaginary bisection line of the corner sector, the first and second half-sectors subtending equal angles about the imaginary bisection line. The blended gash extends from a first extremity and blends an end gash surface and flute rake surface of the corner radius end mill. The blended gash is spaced from a radial tangent point by a predetermined distance, and extends to a second extremity which is spaced apart from the axial line and the second half-sector.

A milling tool comprising a cylindrical shaft part, which has a central axis and which is followed by a cylindrical cutting part comprising at least three circumferential cutting edges, which run helically and which are separated from one another by chip grooves. The circumferential cutting edges continue via cutting edge corner regions in end cutting edges, which run essentially radially and which subsequently slope away from the milling cutter face towards the central axis from radially outer end cutting edge sections, in each case with a cutting edge section, which is formed by ground-in end pockets. The cutting edge section slopes continuously all the way to the central axis. In the region of the milling cutter core, it is formed by a point thinning, which is introduced into the end pocket and by means of which a center cutting edge is created. Also, a method for producing the milling tool.

An end mill includes a plurality of teeth and flutes. The teeth and their associated flutes include one or more correlated physical parameters. One such correlated parameter is that, at an axial location in a front half of an effective cutting length, at least one tooth of the plurality of teeth has a rake angle smaller than an average rake angle value of the plurality of teeth, and, at the same axial location, a flute preceding each such tooth has a helix angle larger than an average helix angle value of the plurality of flutes.

A rotary cutting tool that implements a chip space in proportion to a feed-per-tooth is proposed. The rotary cutting tool includes a cutting part in which a plurality of cutting teeth and flutes are alternately formed, wherein a cross-section of the cutting part perpendicular to a central axis is divided into a plurality of cutting tooth spaces defining a section between cutting edges of adjacent cutting teeth on the basis of the central axis, such that all of the cutting tooth spaces are designed in different sizes, or some of the plurality of cutting tooth spaces are set in different sizes from the other cutting tooth spaces.