WO2016020047A1

WO2016020047A1 - Milling tool

Info

Publication number: WO2016020047A1
Application number: PCT/EP2015/001562
Authority: WO
Inventors: Rainer WALCHER; Julian BAUR; Matthias WALCHER; Jochen WALCHER
Original assignee: Günther Wirth Hartmetallwerkzeuge GmbH & Co. KG
Priority date: 2014-08-06
Filing date: 2015-07-30
Publication date: 2016-02-11
Also published as: AT14275U1

Abstract

The invention relates to a milling tool (1), comprising: a head segment (2), which has a plurality of blades (S1, S2,..., Sn), which extend circumferentially in a spiral shape and which determine a direction of rotation (R) of the milling tool about an axis of rotation (Z), and which has flutes (N1, N2,..., Nn) arranged between the blades; and a clamping segment (3) to be accommodated on a machine tool. At least a first blade (S1) circumferentially extending in a spiral shape and a second blade (S2) circumferentially extending in a spiral shape, which follows the first blade (S1) circumferentially extending in a spiral shape in the direction of rotation (R), the second blade being separated by a second flute (N2), are arranged in such a way that, at each axial position of the head segment (2), the spiral angle (ß) of the second blade (S2) is less than the spiral angle (α) of the first blade (S1) and the core radius (K2) of the second flute (N2) decreases from a free end (2a) of the head segment (2) in the direction of the clamping segment (3).

Description

MILLING TOOL

The present invention relates to a milling tool having a head portion having a plurality of spirally-rotating blades, and a clamping portion for receiving on a processing machine.

Such milling tools come e.g. for a machining of particular metallic materials used and can be a

have different numbers of spirally rotating cutting. Such milling tools are e.g. made of high-speed steel or preferably made of hard metal. In the present case, cemented carbide is understood as meaning a composite material in which hard particles, in particular by carbides,

Carbonitrides and / or oxocarbonitrides of the elements of groups IVb to Vlb of the Periodic Table of the Elements may be formed embedded in a ductile metallic matrix, which may be formed in particular of Co, Ni, Fe or an alloy of these. In most cases, the hard particles are at least predominantly formed by tungsten carbide and the metallic matrix consists of Co. In conventional milling tools of the type described above, the spirally rotating cutting edges are usually formed identical to each other and evenly distributed over the circumference of the head portion. When machining workpieces by milling, the milling tool rotates about an axis of rotation and the cutting occur again and again in the material to be machined and again from this. At identical

trained and evenly distributed cutting result in part relatively large vibrations.

In DE 10 2010 025 148 A1 a milling tool is described, in which the running rest during milling should be increased by making a misalignment of all spirally extending cutting is made, i. the angular intervals in the circumferential direction between adjacent cutting edges are chosen differently, and the spirally running cutting edges have different spiral angles.

CONFIRMATION COPY It is an object of the present invention to provide an improved milling tool, which can be operated in particular very low vibration and thereby provides an improved chip removal. The object is achieved by a milling tool according to claim 1. Advantageous developments are specified in the dependent claims.

The milling tool has a head portion having a plurality of spirally rotating blades defining a rotational direction of the milling tool about an axis of rotation and flutes disposed between each of the blades, and a chuck portion for receiving a processing machine. At least a first spirally revolving cutting edge and a second spirally revolving cutting edge following the first spirally revolving cutting edge separated by a second flute in the rotational direction are arranged such that at each axial position of the head portion the spiral angle of the second cutting edge is smaller than the spiral angle of is the first cutting edge and the core radius of the second flute from a free end of the head portion in the direction of

Clamping section decreases.

If the terms "axial", "radial" or "tangential" are used in the present context, these always refer to the

Rotary axis of the milling tool, unless expressly stated otherwise in the respective context. Under the spiral angle of the cutting edge is to be understood in the present context, the angle that the tangent to the cutting edge when viewed in the radial

Viewing direction (perpendicular to the axis of rotation) on the cutting edge with the

Includes rotation axis. It should be noted that the spiral angle can change in particular over the axial extent of the cutting edge, as will be explained in more detail, so that the spiral angle is to be determined at the respective axial position of the cutting edge. In the present context, the core radius of the flute is understood as meaning in each case the distance of the lowest point of the flute (at the respective axial position of the flute) from the axis of rotation. Since the spiral angle of the first cutting edge at each axial position is greater than the spiral angle of this

subsequent second cutting edge, the first cutting edge in its course from the free end of the head portion to the clamping portion in the circumferential direction rearwardly behind the second cutting edge, so that the tangential width of the second chip flute (thus the angular distance in the circumferential direction between the first cutting edge and the second Cutting edge) decreases with increasing distance from the free end of the head portion. In other words, the second flute thus becomes narrower with respect to its tangential extent in the direction of the chucking section. Since the core radius of the second flute from a free end of the head portion in the direction of

Clamping portion decreases, but at the same time increases the depth of the second flute in the direction of the clamping section. In this way it is achieved that the cross-sectional area of the second flute can be kept substantially constant over the axial length of the head portion, so that a good chip removal over the second flute can be maintained. In comparison with an embodiment in which the core radius of a in

Circumferential direction tapered flute is kept constant, thus improved chip removal is achieved by the flute. Due to the different pitch of the first spirally rotating cutting edge and the second spirally rotating cutting edge while a high smoothness of the

Achieved milling tool.

According to a further development, the spiral angle of the first cutting edge increases from a first value at the free end of the head section to a second value in the region adjoining the clamping section. In other words, this means that the spiral angle becomes larger as the distance from the free end increases. As a result of this embodiment, an improved discharge of chips is achieved, in particular when milling deeper grooves, since the chips are more strongly deflected in the direction of the clamping section in the region of the head section located further in the direction of the clamping section. The spiral angle of the first cutting edge may in particular preferably continuously increase, but it is also possible a different course.

In particular, a linear increase of the spiral angle allows a cost-effective production of the milling tool. According to a further development, the spiral angle of the second cutting edge also increases from a first value at the free end of the head section to a second value in the region adjoining the clamping section, so that the spiral angle of the second cutting edge increases with increasing distance from the free end. Again, the spiral angle of the second cutting edge may preferably increase continuously, but a different course is possible. In particular, a linear increase of the spiral angle allows a cost-effective production of the milling tool. According to a further development, the spiral angle of the first cutting edge increases from a first value a1 at the free end of the head section to a second value a2 in the region adjacent to the clamping section, the spiral angle of the second cutting edge decreases from a first value β1 at the free end of the section Head portion to a second value β2 in the region adjacent to the chucking portion, and the spiral angle of the second cutting edge increases from the free end of the head portion to the region adjacent to the chucking portion more than the helix angle of the first cutting edge, so that: (β2 - β1 )> (α2 - a1). In this case, the

Increasing the initially smaller helix angle of the second cutting edge greater than the increase of the initially larger spiraling angle of the first cutting edge such that the difference in helix angle between the first cutting edge and the subsequent second cutting edge decreases with increasing distance from the free end. In this way it is possible even at a relatively large axial length of the head portion, in the region of the free end to realize a relatively large difference in the spiral angle, which is beneficial to the

Smooth running effect, without resulting in an excessive narrowing of the second flute in the circumferential direction in the area adjacent to the clamping portion. According to a development, the head section n has spirally running cutting edges, with: n e {3; 4; 5; 6}. It has been found that in particular this number of cutting leads to good machining results.

Particularly preferred is an embodiment with 4 or 6 cutting edges

(ie n = 4 or n = 6). According to a development, the head section has n spirally rotating cutting edges and the angular spacing in the circumferential direction between the first spirally rotating cutting edge and the second spirally rotating cutting edge at the free end of the head section is greater than 360 n. In this case, the angular distance between the first cutting edge and the second cutting edge at the free end thus against a uniform

Enlarged division, so that even with a large axial length of

Head portion is prevented from excessive reduction of the width of the second flute in the circumferential direction.

According to a further development, the angular spacing in the circumferential direction between the first spirally rotating cutting edge and the second spirally rotating cutting edge is adjacent to the clamping section

Area smaller than 360 n. In this case, the angular distance between the first cutting edge and the second cutting edge in the vicinity of the clamping portion is thus reduced from a uniform pitch. In this case, the advantageous for the smoothness unequal division of the cutting is very

balanced distributed over the axial length of the head portion, so that results in a particularly advantageous machining behavior.

According to a development, a third spirally encircling cutting edge, which follows the second spirally encircling cutting edge separated by a third chip flute in the direction of rotation, is arranged such that the cutting edge

Spiral angle of the third cutting edge at each axial position of the head portion is greater than the spiral angle of the second cutting edge. In this case, the third cutting edge in its course from the free end of the head portion to the chucking section runs more rearwardly in the circumferential direction than the second cutting edge, so that the tangential width of the third flute (thus the

Angular distance in the circumferential direction between the second cutting edge and the third cutting edge) with increasing distance from the free end of the

Head section increases. In other words, the third flute thus becomes wider with respect to its tangential extension in the direction of the chucking section. In this way becomes a very balanced milling tool

provided in which the reduction of the circumferential distance between the first cutting edge and the subsequent second cutting edge in some way by the increase in the circumferential distance between the second cutting edge and the subsequent third cutting edge

is compensated.

According to a further development, the core radius of the third flute remains constant or increases from a free end of the head section in the direction of the chucking section. In this case, a high stability of the milling tool is preserved, as the wider or in the direction of the clamping section

widening third flute is not deeper with increasing distance from the free end, so that in the vicinity of the chucking a total of a relatively stable core of the milling tool is maintained.

According to a development, the head section has n spirally rotating cutting edges and the angular distance in the circumferential direction between the second spirally rotating cutting edge and the third spirally rotating cutting edge at the free end of the head section is smaller than 360 n. Since the third cutting edge runs away to the rear faster, so in this way, the angular distance between the second cutting edge and the third cutting edge increases with increasing distance from the free end, even in the case of a large axial length of the head section, the angular distance between the second cutting edge and the third cutting edge in the direction of Clamping section becomes too large. When the angular distance in the circumferential direction between the second spirally-rotating cutting edge and the third spirally-rotating cutting edge is greater than 360 ° / n in the region adjacent to the clamping section, the misalignment of the cutting edges is distributed evenly over the axial length of the head section.

According to a development, the head section has a third spiral-shaped cutting edge, which is formed the same as the first spiral-running cutting edge, and a fourth spiral-shaped cutting edge, which is formed the same as the second spiral-cutting cutting edge. Preferably follows the fourth spiraling edge of the third spiral

circumferential cutting edge separated by a fourth flute in the

Direction of rotation and the fourth flute is equal to the second flute formed. In this case, the head section can particularly preferably have a total of four spirally circulating cutting edges. However, implementations with e.g. five or six spirally revolving

Cutting possible.

According to a development, the milling tool is a solid-material milling cutter, in which the head section and the clamping section are integrally formed. Preferably, the milling tool can be made of carbide as

Solid carbide milling cutters be formed. It is also particularly possible that at least the head portion is provided with a hard, wear-resistant coating.

According to a further development, the first cutting edge passes over a cutting corner into a first end cutting edge at the free end of the head section and the third cutting edge merges via a cutting corner into a third end cutting edge at the free end of the head section. Preferably, the first end cutting edge and the third end cutting edge extend parallel to a common plane containing the axis of rotation. Preferably, the first end cutting edge and the third end cutting edge do not extend to a center near the axis of rotation. According to a further development, the second cutting edge passes over a cutting corner into a second end cutting edge at the free end of the head section and the fourth cutting edge merges via a cutting corner into a fourth end cutting edge at the free end of the head section. Preferably, the second end cutting edge and the fourth end cutting edge extend parallel to one another

common plane that contains the axis of rotation.

Preferably, the second end cutting edge and the fourth end cutting edge each extend to a center in the immediate vicinity of the axis of rotation, so that the second end cutting and the fourth cutting edge at least in

Extend substantially to the axis of rotation.

Further advantages and advantages of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying figures.

From the figures show:

1 shows a schematic side view of a milling tool according to an embodiment;

FIG. 2 is a schematic sectional view along a line A - A in FIG

Fig. 1 in the immediate vicinity of a free end, wherein the

Ausspitzung is shown simplified;

3 shows a schematic sectional view along a line B - B in FIG

Figure 1 in a region of the head portion in the vicinity of the chucking portion.

4: an enlarged view of the head section of the

Milling tool of Fig. 1;

Fig. 5 is a graph showing the development of spiral angles from the free end to the chucking portion;

6 shows a graphic illustration (development) which images the cutting edge profile in a plane perpendicular to the axis of rotation in the direction of view; and

Fig. 7: a schematic end view of the free end of

Milling tool of FIG. 1.

Embodiment

An embodiment of the milling tool 1 will be described in more detail below with reference to FIGS. 1 to 7.

The milling tool 1 has a head portion 2 adapted for machining a workpiece, and a chuck portion 3 adapted for receiving a processing machine to be taken up. The milling cutter 1 is formed as a solid milling cutter in which the head portion 2 and the clamping portion 3 are integrally formed of the same material. The milling tool 1 can be formed in particular from hard metal.

The clamping portion 3 has a substantially cylindrical shape about a rotation axis Z. The head portion 2 integrally formed with the chucking portion 3 has a plurality of spirally revolving

Cutting S1, S2, S3, S4, between each of which flutes N1, N2, N3, N4 extend. In the specifically illustrated embodiment, the head section 2 has a total of four spirally rotating cutting edges S1,

S4, it should be noted, however, that a different number of such spirally rotating cutting is possible. The head section 2 can in particular n such spirally encircling cutting S1,

Sn, wherein preferably: n e {3; 4; 5; 6}. The shape of the

Cutting S1, Sn determines the direction of rotation R in which the

Milling tool 1 rotates in operation during machining around the rotation axis Z.

The milling tool 1 according to the illustrated embodiment is e.g. is formed as a right-handed milling tool, but it is also a reverse training as a left-handed milling tool possible in which the spiral shape of the cutting in the opposite direction.

The spirally rotating cutting edges S1, S2, S3, S4 are designed to chip material from the workpiece to be machined during operation of the milling tool 1. The flutes N1, N2, N3, N4 spirally extending between the respective cutting edges S1, S2, S3, S4 are designed to derive the chips formed during the machining operation, wherein in the context of the present description the numbering of the flutes is in each case with regard to the assigned cutting edge, whose chips are derived, is selected. In other words, the first flute N1 is thus arranged with respect to the rotation direction R in front of the first blade S1, the second flute N2 is arranged in front of the second blade S2, etc. The individual spirally encircling cutting edges S1, S2, S3, S4 each proceed at a free end 2a of the head section 2 via cutting corners into associated end cutting edges SS1, SS2, SS3, SS4, which engage on the

End face of the milling tool 1 substantially perpendicular to the

Rotary axis Z extend. Although in the illustrated embodiment cutting corners are shown with a relatively small transition radius from the spirally rotating cutting edge to the respective associated end cutting edge, depending on the application, e.g. also possible to provide more rounded cutting corners. Although the end cutting SS1,

SS4 in the illustrated embodiment each extend substantially perpendicular to the axis of rotation, it is e.g. depending on

Application also possible to provide differently shaped end cutting. In particular, the end cutting edges can optionally be curved.

As can be seen in Fig. 7, those of the first extend spirally

circulating cutting edge S1 associated first end cutting SS1 and

the third spirally encircling cutting edge S3 associated third

End cutting SS3 parallel to a common plane that the

Rotation axis Z contains. The first end cutting SS1 and the third

End cutting SS3 do not extend in each case to the

Center area after the axis of rotation Z, but already end radially further out on a recess. The second end cutting edge SS2 assigned to the second spirally revolving cutting edge S2 and the fourth cutting cutting edge SS4 assigned to the fourth spirally revolving cutting edge S4 likewise extend parallel to a common plane which contains the axis of rotation Z, as can be seen in FIG. As can be clearly seen in the end view of FIG. 7, the common plane of the first end cutting edge SS1 and the third extend

End cutting SS3 and the common plane of the second end cutting SS2, and the fourth end cutting SS4 due to an imbalance of

Cutting at the free end 2a of the head portion 2 is not perpendicular to each other. As is also clearly visible in the end view of FIG. 7, the milling tool 1 according to the illustrated embodiment has a

two-fold rotational symmetry with respect to the axis of rotation Z, so that the first cutting edge S1 and the first end cutting SS1 by rotation through 180 ° about the axis of rotation in the third cutting S3 and the third

End cutting SS3 can be transferred and equally the second cutting S2 and the second end cutting SS2 in the fourth cutting edge S4 and the fourth end cutting SS4 can be converted. However, in contrast to the first and the third end cutting edge, the second end cutting edge SS2 and the fourth end cutting edge SS4 extend as far as a center region near the axis of rotation Z, where they are connected to each other by a short transverse cutting edge. However, instead of such a connection via a chisel edge it is e.g. also possible, the second

End blade SS2 and the fourth end cutting SS4 in a common, the rotation axis Z containing plane, so that they converge directly in the center on the axis of rotation Z.

The course of the spirally rotating cutting edges S1, S2, S3 and S4 will be described in more detail below, wherein to avoid

Repeats only the cutting edges S1 and S2 are described in more detail, since in the embodiment, the third cutting S3 is formed identical to the first cutting S1 and the fourth cutting edge S4 identical to the second cutting S2. Similarly, the third flute N3 is identical to the first flute N1 formed and the fourth flute N4 identical to the second flute N2.

As can be seen in particular in Fig. 1 and Fig. 4, run the

Cutting S1, S2, S3, S4 from the free end 2a of the head portion 2 in the direction of the chucking portion 3, respectively, spirally toward the rear and into a region 2b of the chuck portion 3 adjacent to the chuck portion 3

Head section 2. Between the cutting edges are also each

formed spirally to the rear running away flutes N1, N2, N3, N4. The cutting edges extend at each point of the cutting edge under one determined spiral angle to the axis of rotation R, wherein the helix angle is determined by the angle between the axis of rotation and a tangent to the cutting edge in the respective point in radial plan view to the point of the cutting edge. For example, the first cutting edge S1 extends below one

Spiral angle ot. In the concrete embodiment, however, the spiral angle α is not constant over the axial extension of the head section 2, but instead changes from a first value a1 at the free end 2a of FIG

Kopfabschnittes 2 to a second value a2 in the at the

Clamping section 3 adjacent area 2b. The third cutting edge S3 extends at a spiral angle γ, which changes in accordance with the spiral angle α of the first cutting edge S1 from a first value γ1 at the free end 2a to a second value γ2 in the region 2b adjoining the clamping section 3. In the embodiment, the spiral angle α (or γ) increases continuously from the free end 2a in the direction of

Clamping section 3, in particular, the spiral angle increases linearly with increasing distance from the free end 2a, as shown in Fig. 5 is shown graphically. Due to the symmetry of the milling tool applies in the

Embodiment (α = γ and thus a1 = γ1 and a2 = y2). The second blade S2 extends at a spiral angle β whose

In the concrete embodiment, the size also changes from the free end 2a in the direction of the clamping section from a first value β1 to a second value β2. The fourth cutting edge S4 accordingly extends at a helix angle δ, with δ = β and thus 51 = β1 and 52 = β2. Also, the spiral angle ß of the second cutting S2 increases from the free end 2a in the direction of the clamping section 3, in the concrete

Embodiment in particular linear. Although at the concrete

Embodiment, a linear increase of the spiral angle α, ß, γ, 5 is realized in the direction of the clamping section 3, which has a positive effect in the production, other courses of such increase are possible.

The increase in the spiral angle in the direction of the clamping section 3 has the advantage that when milling, for example, deeper grooves, the chips better can be dissipated without preventing a relatively soft cut. In one possible implementation, for example, α1 = γ1 = 22 °;

α2 = γ2 = 42 °; β1 = δ1 = 17 ° and β2 = 52 = 40 °, although other suitable angles are possible. As can be seen in particular in Fig. 5, is the

Spiral angle α of the first blade S1 over the entire axial extent in each case greater than the spiral angle ß of the second blade S2, as in

The following will be explained in more detail.

Although it is described as a preferred embodiment that the spiral angles change over the axial extent of the head portion 2 respectively, which is advantageous in terms of the removal of chips, it is in a modification of e.g. but also possible to keep the respective spiral angle over the axial length of the head portion 2 constant. In this case too, however, the spiral angle α of the first cutting edge S1 is greater than the spiraling angle β of the second cutting edge S2, i. it is α> ß.

Since the spiral angle α of the first blade S1 is greater than the spiral angle β of the second blade S2 following the first blade S1 in the direction of rotation R, the first blade S1 moves rearward faster than the second with increasing distance from the free end 2a Cut S2. Thus, the first blade S1 approaches in the circumferential direction of the second blade S2 and the width of the second flute N2 therebetween approaches

The circumferential direction becomes progressively smaller in the direction of the clamping section 3. In other words, the pitch angle between the first blade S1 and the second blade S2 becomes smaller as the distance from the free end 2a increases.

Since the spiral angle γ of the third cutting edge S3 is larger than the spiraling angle β of the second cutting edge S2, the third cutting edge S3 following the second cutting edge S2 in the direction of rotation R runs backwards faster than the second one

Cut S2. Thus, the width of the third located therebetween becomes

Flute N3 in the circumferential direction with increasing distance from the free end 2a larger. In other words, the pitch angle between the Second cutting S2 and the third cutting S3 with increasing distance from the free end 2a larger.

Thus, the first cutting edge S1 increasingly approaches the second cutting edge S2 in the direction of the clamping section 3. Due to the symmetry in the embodiment, similarly, the third blade S3 approaches in the direction of the portion 2b of the fourth adjacent to the chucking portion 3

Cut S4. This circumferential approximation can be seen in the graph of Fig. 6, where the distance between the

Cutting along the horizontal axis respectively the circumferential

Distance between the cutting edges corresponds to and the vertical axis of the

Direction of the rotation axis Z corresponds. On the other hand, the

circumferential width of the first flute N1 as well as the circumferential width of the third flute N3 with increasing distance from the free end 2a to. The imbalance of the cutting edges S1, S2, S3, S4 thus changes over the axial extension of the head region 2.

The reduction in the width of the second flute N2 (and the fourth

Chip flute N4) with increasing distance from the free end 2a would, without countermeasure, bring about a reduction in the cross-section available for chip removal, so that chip removal would be impaired. In the embodiment, however, the second flute N2 (and the fourth flute N4) is formed such that the core radius K2 of the second flute N2 decreases as the distance from the free end 2a increases

in particular in the sectional views in Fig. 2 and Fig. 3 can be seen. The core radius is determined in each case (at each axial position of the flute) by the radial distance of the lowest point of the flute from the axis of rotation Z. The decrease in the core radius K2 of the second flute N2 can thereby be selected such that the cross-sectional area of the second flute N2 remains approximately constant in a plane perpendicular to the axis of rotation Z over the axial extent of the head section 2.

As can also be seen in FIGS. 2 and 3, the core radius K3 of the third flute N3 in the embodiment remains over the axial extent of the Head section 2 at least substantially constant, so that a total of a stable core of the milling tool 1 is maintained. According to a modification of the embodiment, the core radius K3 of the third

Flute N3 (and analogous to the core radius K1 of the first flute N1) also be designed such that it increases with increasing distance from the free end. In this case, however, the core radius should at most increase to an extent that is available for chip removal

Cross section of the flute is not reduced over a large part of the axial length of the head portion 2 with increasing distance from the free end 2a.

It has been described that the first cutting edge S1 approaches the second cutting edge S2 with increasing distance from the free end 2a and the third cutting edge S3 approaches the fourth cutting edge S4 in the same way, due to the spiral angles α, γ of the first cutting edge S1 and third cutting edge are larger than the helix angles β, δ of the second and fourth cutting edges. To an excessive reduction in the width of the second flute N2 and the fourth

To counteract flute N4, the increase of the spiral angle with increasing distance from the free end 2a at the second blade S2 (and the fourth blade S4) is greater than in the first blade S1 (and the third blade S3), as shown in Fig. 5 and Fig. 6 can be seen so that:

(ß2 - ß1)> (a2 - cd) and due to the symmetry (52 - 51)> (γ2 - γ1). In this way, it is achieved that the difference in the spiral angle in the direction of the chucking section 3 becomes progressively smaller, and the width of the second flute N2 and the fourth flute N4 thus decreases progressively more slowly.

Due to the approach of the first blade S1 to the second blade S2 with increasing distance from the free end 2a of the head portion 2, the angular distance in the circumferential direction TW2 between the first blade S1 and the second blade S2 decreases with increasing distance from the free end 2a. As can be seen in FIGS. 2 and 3, the

Angular distance in the circumferential direction TW2 between the first blade S1 and the second blade S2 at the free end selected such that it is greater than 3607η, where n is the number of spirally rotating blades. For the concretely illustrated case of an embodiment with four spirally rotating cutting edges S1, S2, S3, S4 (ie n = 4), the angular distance in the circumferential direction TW2 between the first cutting edge S1 and the second cutting S2 at the free end is thus more than 90 ° , In the embodiment, the misalignment of the blades is realized such that the angular distance in the circumferential direction TW2 between the first blade S1 and the second blade S2 in the region 2b adjacent to the chucking portion 3 is smaller than 360n, that is, in the case of n = 4 less than 90 °. Due to the realized geometry, the same applies to the angular distance in

Circumferential direction TW4 between the third blade S3 and the fourth blade S4. In this way, the misalignment of the blades is distributed very well over the axial length of the head portion 2, and an excessive reduction in the width of the second flute N2 with increasing distance from the free end 2a is prevented.

On the other hand, the angular distance in the circumferential direction TW3 between the second blade S2 and the third blade S3 at the free end 2a is less than 360 n, that is, less than 90 ° in the specific case of n = 4, and the angular distance in the circumferential direction TW3 between the second The cutting edge S2 and the third cutting edge S3 in the region 2b adjoining the clamping section 3 are more than 3607n, that is more than 90 ° in the specific case of n = 4. Due to the realized symmetry, the same applies to the

Angular distance in the circumferential direction TW1 between the fourth blade S4 and the first blade S1, as also shown in FIGS. 2 and 3 can be seen.

Claims

claims

1. milling tool (1) with:

a head portion (2) having a plurality of spirally - rotating blades (S1, S2, Sn), which has a rotational direction (R) of

Milling tool about a rotation axis (Z) determine, and in each case arranged between the cutting flutes

(N1, N2, Nn), and

a clamping portion (3) for receiving at a

Processing machine,

wherein at least a first spirally revolving cutting edge (S1) and a second spirally revolving cutting edge (S2) following the first spirally revolving cutting edge (S1) separated by a second flute (N2) in the direction of rotation (R) are arranged such that

at each axial position of the head portion (2), the spiral angle (β) of the second cutting edge (S2) is smaller than the spiral angle (a) of the first one

Cutting edge (S1) is and

the core radius (K2) of the second flute (N2) decreases from a free end (2a) of the head portion (2) toward the chucking portion (3).

2. Milling tool according to claim 1, wherein the helical angle (a) of the first cutting edge (S1) from a first value a1 at the free end (2a) of the head portion (2) to a second value a2 in which the

Clamping section (3) adjacent area (2b) increases.

3. Milling tool according to claim 1 or 2, wherein the spiral angle (ß) of the second cutting edge (S2) from a first value ß1 at the free end (2a) of the head portion (2) to a second value ß2 in the at

Clamping section (3) adjacent area (2b) increases. Milling tool according to one of the preceding claims, wherein the spiral angle (a) of the first cutting edge (S1) and the helix angle (β) of the second cutting edge (S2) respectively from the free end (2a) of

Head section (2) in the direction of the chucking section (3) continuously increase.

Milling tool according to one of the preceding claims, wherein the spiral angle (a) of the first cutting edge (S1) from a first value a1 at the free end (2a) of the head portion to a second value a2 in the area adjacent to the clamping portion (3) (2b ), the spiral angle (β) of the second cutting edge (S2) increases from a first value β1 at the free end (2a) of the head section (2) to a second value β2 in the region (2b) adjacent to the clamping section (3) , and

the helix angle (β) of the second cutting edge (S2) from the free end (2a) of the head section (2) to the clamping section (3)

adjacent region (2b) increases more than the spiral angle (a) of the first cutting edge (S1), so that: (β2 - β1)> (α2 - a1).

Milling tool according to one of the preceding claims, wherein the

Head section (2) n spiral cutting edges (S1 Sn) with: n e {3; 4; 5; 6}.

Milling tool according to one of the preceding claims, wherein the head portion (2) has n spirally rotating cutting edges (S1, S2, Sn) and the angular distance in the circumferential direction (TW2) between the first spirally rotating cutting edge (S1) and the second

spiral-shaped cutting edge (S2) at the free end (2a) of the head section (2) is greater than 360 n.

8. Milling tool according to claim 7, wherein the angular distance in

Circumferential direction (TW2) between the first spirally rotating cutting edge (S1) and the second spirally rotating cutting edge (S2) in the region (2b) adjacent to the clamping section (3) is less than 360 n.

9. Milling tool according to one of the preceding claims, wherein a third spirally encircling cutting edge (S3) which follows the second spirally revolving cutting edge (S2) separated by a third flute (N3) in the direction of rotation (R), is arranged such that

the helix angle (γ) of the third cutting edge (S3) at each axial position of the head portion (2) is greater than the helix angle (β) of the second cutting head (3)

Cutting edge (S2) is.

10. Milling tool according to claim 9, wherein the core radius (K3) of the third flute (N3) from a free end (2a) of the head portion (2) in the direction of the chucking section (3) remains constant or increases.

11. Milling tool according to claim 9 or 10, wherein the head portion (2) has n spirally rotating cutting edges (S1, S2, Sn) and the angular distance in the circumferential direction (TW3) between the second

helically rotating cutting edge (S2) and the third spiraling cutting edge (S3) at the free end (2a) of the

Head section (2) is less than 360 n.

12. Milling tool according to claim 11, wherein the angular distance in

Circumferential direction (TW3) between the second spirally rotating cutting edge (S2) and the third spirally rotating cutting edge (S3) in the region (2b) adjacent to the clamping section (3) is greater than 3607n.

13. Milling tool according to one of the claims, wherein the head portion has a third spirally revolving cutting edge (S3) which is formed like the first spirally revolving cutting edge (S1), and a fourth spirally revolving cutting edge (S4) which is equal to the second spirally revolving cutting edge (S3). S2) is formed has.

14. Milling tool according to claim 13, wherein the fourth spirally

circumferential cutting edge (S4) of the third spirally revolving

Cutting edge (S3) separated by a fourth flute (N4) in the

Direction of rotation (R) follows, and

the fourth flute (N4) is formed equal to the second flute (N2).

15. Milling tool according to one of the preceding claims, wherein the milling tool is a solid material cutter, wherein the head portion and the clamping portion are integrally formed.