End mill

Abstract

The invention relates to an end mill. An end mill, preferably made of solid cemented carbide, is provided with a fastening portion and a cutting region. The cutting region is formed by a core and at least two cutting edges, which are arranged around the core and extend helically around the axis of rotation of the end mill, each of said cutting edges having in each case a circumferential main cutting edge and a secondary cutting edge on the end face of the cutting region. At least one first chisel edge of the core between two (first) mutually adjacent cutting edges and at least one second chisel edge between two (other or second) mutually adjacent cutting edges are arranged on the end side of the cutting region. The end mill is further distinguished in that the first chisel edge is designed to be geometrically different from the second chisel edge. Further, the first chisel edge will have a (chisel edge) angle of 30 DEG to 45 DEG, and the second chisel edge will have a (chisel edge) angle of 35 DEG to 50 DEG (always with respect to the normal plane of the rotational axis of the end mill (e.g., proximal side)). Further, the first chisel edge will have a (chisel edge) field angle of 30 DEG to 50 DEG, and the second chisel edge will have a (chisel edge) field angle of 40 DEG to 60 DEG (the field angle is always an angle between side surfaces of the chisel edges in a top view viewed toward the end side of the end mill).

Description

[0001] The present invention relates to an end mill for subtractive machining of metallic materials, in particular steel and titanium, according to the preamble of claim 1.

[0002] From DE 10 2015 116 623 A1, an end mill is known which has a fastening part and a cutting region. The cutting region is formed by a rotationally symmetric core and, in this case, four cutting edges which are arranged helically around the core and are integrally connected to the core.

[0003] Each of these four cutting edges has a circumferential main cutting edge and a secondary cutting edge on the free end side of the cutting region. As a result, good surface quality is achieved when face milling is carried out using the secondary cutting edge.

[0004] However, a disadvantage of end mills of this type is that they are not suitable for boring operations, and thus subtractive machining is carried out using the proximal secondary cutting edge in the feed direction which is essentially along the rotational axis of the end mill, because there are no cutting edges in the region close to the center.

[0005] Even in the case of tools in which at least a part of these cutting edges extends essentially to the rotational axis of the end mill, the boring operation is difficult because reliable chip removal cannot be ensured.

[0006] Furthermore, in order to carry out a boring operation or subtractive machining over the entire end side, the end mill from DE 102015 116623A1 has core cross edges between the respective adjacent cutting edges on its end side.

[0007] In the end mill of DE 10 2015 116 623 A1, the size of the cross edges is determined to be between 30° and 40° respectively (between the second cutting edge and the third cutting edge, and between the fourth cutting edge and the first cutting edge) and between 20° and 40° (between the first cutting edge and the second cutting edge, and between the third cutting edge and the fourth cutting edge).

[0008] DE 10 2015 116 623 A1 sets or determines the size of the cross edge angle mentioned relative to the rotational axis of the end mill.

[0009] When measured, for example, with respect to the proximal-side normal plane of the rotational axis of an end mill, the end mill from DE 10 2015 116 623 A1 provides chisel edges that are between 50° and 60° (between the second cutting edge and the third cutting edge, and between the fourth cutting edge and the first cutting edge), and between 50° and 70° (between the first cutting edge and the second cutting edge, and between the third cutting edge and the fourth cutting edge). This means that the dimensioned chisel-edge angle provided here is the angle enclosed between (1) the connecting line / straight line that connects the deepest point of the chisel edge (i.e., the point that is furthest from the end side in the axial direction) to the penetration point where the rotational axis of the end mill passes through the proximal-side normal plane of the end mill, and (2) the proximal-side normal plane.

[0010] Accordingly, the end mill from DE 10 2015 116 623 A1 has chisel edges that extend extremely steeply, which does improve the boring operation, yet this is achieved at the expense of the tooth thickness and tooth stability and thus of the stiffness of the end mill and the quality during face milling.

[0011] The object of the present invention is to improve the end mills known from the prior art, in particular to further improve them so that they can achieve good quality during face milling and boring operations.

[0012] This object is achieved by an end mill having the features of the independent claims.

[0013] The present invention advantageously improves the subject matter of the dependent claims and the following description.

[0014] Unless otherwise explicitly defined, any terms used (such as above, below, front, back, left or right) will be understood according to the normal understanding and also with respect to this drawing. Terms such as radial and axial, when used and not otherwise explicitly defined, should be understood with reference to the central axis or symmetry axis of the components described here and also with respect to this drawing.

[0015] When used, the term "substantially" can (according to the understanding of the Supreme Court) be understood to mean "still to a quite significant extent in fact". Thus, due to manufacturing or assembly tolerances etc., the possible deviation from precision implied by this term may occur inadvertently (that is, without any functional basis).

[0016] An end mill preferably made of solid carbide is provided with a clamping portion and a cutting region. The cutting region is formed by a core and at least two, in particular four (or even more, an even number (such as six or eight)) cutting edges that are arranged around the core and extend helically around the rotational axis of the end mill, each of the cutting edges having in each case a circumferential main cutting edge and a secondary cutting edge on the end side of the cutting region, i.e., a proximal-side secondary cutting edge.

[0017] At least one first cross-edge of the core between (first) two mutually adjacent cutting edges and at least one second cross-edge between two (other or second) mutually adjacent cutting edges are provided on the end side of the cutting region.

[0018] The end mill is further distinguished in that the first cross-edge is designed to be geometrically different from the second cross-edge or is different from the second cross-edge in terms of geometry. In other words, simply put, the end mill implements at least two (geometrically) different cross-edges.

[0019] Furthermore, the first cross-edge will have a (cross-edge) angle of 30° to 45°, in particular 32° to 38°, especially approximately 35°, and the second cross-edge will have a (cross-edge) angle of 35° to 50°, in particular 39° to 46°, especially approximately 42.5° (always with respect to the normal plane of the (e.g., proximal side) of the rotational axis of the end mill).

[0020] In the end mill here, the cross-edge angle is measured or stated with respect to, for example, the normal plane of the proximal side of the rotational axis of the end mill. This means that the cross-edge angle measured here is the angle enclosed between (1) the connecting line / straight line that connects the deepest point of the (1) cross-edge (i.e., the point furthest from the end side in the axial direction) to the penetration point where the rotational axis of the end mill passes through the normal plane of the proximal side of the end mill and (2) the normal plane of the proximal side.

[0021] Furthermore, the first cross-edge will have a spreading angle of 30° to 50°, in particular 35° to 45°, especially approximately 40°, and the second cross-edge will have a spreading angle of 40° to 60°, in particular 41° to 50°, especially approximately 42.5° (this spreading angle is always the angle between the sides of the cross-edge in the top view looking at the end side of the end mill).

[0022] Here, the cross-edge spreading angle should be measured as the angle between the sides of the cross-edge in the top view looking at the end side of the end mill. In other words, in the top view looking at the end side of the end mill, these sides of the cross-edge converge at the angle that appears in this perspective view, and this angle is specifically the cross-edge spreading angle here. (The ends of this angle can optionally also be rounded.)

[0023] Here, the cross-edge can include any design embodiment by which the material of the core and potentially also the material of the cutting edge in the region of the end side of the cutting edge region is reduced circumferentially between these cutting edges to a limited local extent.

[0024] The core shall be understood to mean the rotationally symmetric core region of the end mill in the cutting area. These cutting edges are arranged around the core and are integrally formed with the core. The base of each chip removal groove (the chip removal groove is formed between these cutting edges in the circumferential direction) is defined by the core.

[0025] In an advantageous embodiment, the chisel edge can be formed as a clearance in the region of the end side of the cutting area, which clearance approaches the rotational axis of the end mill in the direction from the clamping part to the end side of the cutting area. For example, this type of clearance can be particularly easily achieved by grinding.

[0026] The end mill is based on the knowledge or concept that the ability of the end mill in boring operations increases or improves as the chisel edge angle increases, so the chisel edge angle becomes larger or steeper. However, the tooth thickness decreases as the chisel edge increases, or the chisel edge angle becomes larger / steeper, which impairs or potentially impairs the strength and stiffness of the end mill and the quality of the end mill during face milling.

[0027] Based on this recognition, the end mill according to the invention now attempts to find a compromise in these competing requirements (i.e., chip removal and boring operations and stability during face milling).

[0028] It has been unexpectedly proven here that when a larger first chisel edge angle is implemented, this helps the boring operation but may impair face milling, and the possible "impairing aspects" can be "compensated" by also implementing a smaller second chisel edge angle at the same time, so as to meet or be able to meet the competing requirements.

[0029] However, as has also been proven, on the one hand, the two different "competing" chisel edges should not or must not be within the extreme marginal ranges (e.g., less than 20° or greater than 70°), and on the other hand, they should not be too far apart or deviate too much from each other, because in this bilateral "extreme" (absolute and relative) situation, the competing effects may no longer be offset or compensated.

[0030] This applies in a similar way to the (chisel edge) opening angle provided by the end mill. Here too, a large (chisel edge) opening angle provides sufficient space for chip removal and / or has a positive effect on the boring operation, but material is removed from the tooth, which also reduces the stiffness. Here too, the first (chisel edge) opening angle and the second (chisel edge) opening angle also achieve a compromise between the competing effects, or can compensate for the competing effects, as has been unexpectedly proven.

[0031] This means that the end mill according to the invention achieves the expertise of "coordinating" or compensating for opposite effects through the "balanced distribution" of its chisel edges within the middle range of the chisel edge (i.e., on the one hand, a first smaller chisel edge and, on the other hand, a second larger (in terms of value) chisel edge not too far from the first chisel edge), thus achieving a positive compromise between good boring operation and face milling (or sufficient stiffness for these operations).

[0032] Furthermore, this end mill according to the invention is also easy to produce and cost-effective due to its "balanced distribution of chisel edges".

[0033] Specifically, for implementing the balance and compensation, it can preferably be provided that the first chisel edge has an (chisel edge) angle of 32° to 38°, in particular approximately 35°, and the second chisel edge has an (chisel edge) angle of 39° to 46°, in particular approximately 42.5°.

[0034] This also applies in a similar manner to the preferred chisel edge rake angles, which can preferably be implemented such that the first chisel edge has a rake angle of 35° to 45°, in particular approximately 40°, and the second chisel edge has a rake angle of 41° to 50°, in particular approximately 42.5°.

[0035] It also appears particularly advantageous to implement a plurality of first chisel edges and second chisel edges, wherein the first chisel edges and the second chisel edges alternate with each other in the circumferential direction on the end side of the end mill.

[0036] It is also beneficial that the proximal side auxiliary cutting edge of the first cutting edge of the first tooth is longer than the proximal side auxiliary cutting edge of the second cutting edge of the second tooth, wherein the first chisel edges together form the chip space of the first cutting edge or the first tooth, and the second chisel edges together form the chip space of the second cutting edge or the second tooth.

[0037] Similarly, it can be provided that there are a plurality of first teeth or first cutting edges with longer proximal side auxiliary cutting edges and chip spaces with first chisel edges, and a plurality of second teeth or second cutting edges with shorter proximal side auxiliary cutting edges and chip spaces with second chisel edges, wherein the longer proximal side auxiliary cutting edges and the shorter proximal side auxiliary cutting edges alternate with each other in the circumferential direction of the cutting part on the end side of the end mill through their respective first chisel edges and second chisel edges.

[0038] It has also been proven beneficial that the first chisel edge and the second chisel edge (starting from the end side) terminate at substantially the same axial height in the cutting area.

[0039] According to a preferred design embodiment, it can be provided that the cutting region includes a total of four cutting edges, wherein the first cutting edge and the third cutting edge, and the second cutting edge and the fourth cutting edge among these cutting edges are substantially opposite to each other or approximately diametrically opposite to each other, and a first cross edge is provided between the first cutting edge and the second cutting edge and between the third cutting edge and the fourth cutting edge, and a second cross edge is provided between the second cutting edge and the third cutting edge and between the fourth cutting edge and the first cutting edge.

[0040] Furthermore, it has also proven advantageous that these cutting edges are unevenly distributed in the circumferential direction of the cutting region. Such uneven distribution can be established, for example, with respect to a predefinable axial height, particularly for the end face of the end mill (corresponding to a height of 0 mm) or at a height approximately 0.5*D (D = diameter of the cutting region) axially below the end face of the end mill.

[0041] In particular, it can also be provided herein that, in the mentioned non-uniform distribution, at a predefinable axial height in the circumferential direction of the cutting region and in the cutting region, the angle between the first cutting edge and the second cutting edge and the angle between the third cutting edge and the fourth cutting edge are each greater than 90°, particularly approximately 97.5°, and / or the angle between the second cutting edge and the third cutting edge and the angle between the fourth cutting edge and the first cutting edge are each less than 90°, particularly approximately 82.5°. In particular, the predefinable axial height is the end face of the end mill (corresponding to a height of 0 mm) or at a height approximately 0.5*D (D = diameter of the cutting region) axially below the end face of the end mill.

[0042] It can also be provided that the circumferential main cutting edges of the cutting edges have different helix angles. In particular, the circumferential main cutting edges of the cutting edges have a first helix angle alternating with a second helix angle different from the first helix angle in the circumferential direction of the cutting region.

[0043] It may also be beneficial to implement a specific geometry in these cutting edges.

[0044] In this way, it can be provided that the end face of the cutting edge on the secondary cutting edge (particularly the end face of each cutting edge) has a clearance angle between 5° and 7°, particularly approximately 6°, with respect to a plane perpendicular to the rotational axis of the end mill.

[0045] It can also be provided that the chip space proximal (end) face of the secondary cutting edge (particularly each secondary cutting edge) has a rake angle between 2° and 4°, particularly approximately 3°, with respect to a plane parallel to the rotational axis of the end mill.

[0046] Furthermore, it can be provided that the proximal-side secondary cutting edge and the circumferential main cutting edge of the cutting edge transition into one another via a corner chamfer, in particular a corner chamfer having a corner chamfer angle of approximately 45°.

[0047] It has also proven beneficial that the core of the end mill has a cylindrical design.

[0048] Furthermore, in a preferably designed embodiment, it can be provided that at least the cutting area is coated, in particular with a coating having a layer thickness between 0.0010 mm and 0.006 mm, in particular between 0.0015 mm and 0.005 mm, especially between 0.0018 mm and 0.004 mm.

[0049] It has also proven advantageous that the end mill is made of solid carbide.

[0050] The description of the advantageous designs of the present invention given so far includes many features reproduced in the respective dependent claims, which in some cases are reproduced together. However, these features can also advantageously be considered individually and combined into suitable further combinations.

[0051] Even if some terms are used in the singular form in the description and / or claims or in combination with numbers, the scope of the present invention is not intended to be limited to the singular form of these terms or the corresponding numbers. Furthermore, the words "a" or "an" should not be understood as numerals but as indefinite articles.

[0052] In connection with the following description of exemplary embodiments of the present invention, the above-mentioned properties, features, and advantages of the present invention and the ways of achieving them will become clearer and more clearly understandable, and will be explained in more detail in connection with the accompanying drawings / figures (in the accompanying drawings / figures, the same components and functions are denoted by the same reference signs).

[0053] The exemplary embodiments are used to explain the present invention without limiting the present invention to the combinations of features specified therein, including combinations of functional features. Furthermore, for this purpose, the suitable features of each exemplary embodiment can also be clearly considered individually, taken from one exemplary embodiment, introduced into another exemplary embodiment to supplement it, and combined with any one of the claims.

[0054] In the figures:

[0055] Figure 1 A side view of a solid carbide end mill according to an embodiment of the present invention is shown, which solid carbide end mill has a cutting area and a fastening part;

[0056] Figure 2 Shows a front view of the free end side of the solid carbide end mill from Figure 1 ...

[0057] Figure 3 shows an image of the free end side of a solid carbide end mill from Figure 1 ;

[0058] Figure 4-1 (long chisel edge) and Figure 4-2 (short chisel edge)

[0059] in each case show images of side views of solid carbide end mills with a chisel edge at the long or short chisel edge respectively from Figure 1 ;

[0060] -(solid carbide) end mill ( Figure 1 and FIG. 4)

[0061] Figure 1 and Figure 2 show (schematically) the end mill 1 (made of solid carbide) in various views and details. Figure 1 The solid carbide end mill 1 is shown here in a side view; Figure 2 The solid carbide end mill is shown in a front view of the (free) end side 12 of the solid carbide end mill 1. Figure 3 FIGS. to 4 show images of the solid carbide end mill 1 in each case from different perspectives (end side, side).

[0062] The solid carbide end mill 1 has a clamping portion 2 and a cutting region 3, which in this case has four teeth 4, 5, 6 and 7 or four cutting edges 4, 5, 6 and 7.

[0063] The clamping portion 2 has a cylindrical shape and is designed to be received in a chuck of a workpiece machining machine (such as a CNC milling center (not shown)).

[0064] The cutting region 3 is adjacent to the clamping portion 2 and is formed by a core 8 (which is cylindrical in design in this case) and by cutting edges 4, 5, 6 and 7 or teeth 4, 5, 6 and 7 arranged around the core 8.

[0065] The cutting edges / teeth 4, 5, 6 and 7 herein extend helically around the rotational axis 9 of the solid carbide end mill 1 and are integrally formed with the (cylindrical) core 8.

[0066] Each cutting edge 4, 5, 6 and 7 has in each case a circumferential main cutting edge 10 and a (proximal side) secondary cutting edge 11 on the end side 12 of the cutting region 3, and the cutting edges are designed to interact in a subtractive manner with a workpiece (not shown) to be machined during rotation of the solid carbide end mill 1 around the rotational axis 9.

[0067] For the sake of clarity, in the illustrations in the figures, the reference signs for the main cutting edges 10 and the secondary cutting edges 11 of all cutting edges 4, 5, 6, and 7 are not shown in their entirety; however, each of the cutting edges 4, 5, 6, and 7 has a (circumferential) main cutting edge 10 and a (proximal-side) secondary cutting edge 11.

[0068] As Figure 2 also shown in, the proximal-side secondary cutting edges 11 of the cutting edges 4 and 6 herein are longer than the proximal-side secondary cutting edges 11 of the cutting edges 5 and 7. For this reason, hereinafter, in the case of the "long" cutting edges 4 and 6, reference is also made to the "long teeth" 4 and 6, and in the case of the "short" cutting edges 5 and 7, reference is also made to the "short teeth" 5 and 7.

[0069] The proximal-side secondary cutting edges 11 and the circumferential main cutting edges 10 of all cutting edges 4, 5, 6, and 7 transition into one another in each case via a corner chamfer 18 (in particular a corner chamfer having a corner chamfer angle α of approximately 45°).

[0070] Furthermore, in the region of the end side 12 of the cutting region 3 (in this case corresponding to the number of the four cutting edges 4, 5, 6, and 7), four cross edges 13-1, 13-2, 13-3, and 13-4 of the core 8 are provided, and each of these cross edges together forms a chip removal space 16-1, 16-2, 16-3, and 16-4 for the corresponding cutting edges 4, 5, 6, and 7 (cross edge 13-1 for cutting edge 4, cross edge 13-2 for cutting edge 5, cross edge 13-3 for cutting edge 6, and cross edge 13-4 for cutting edge 7).

[0071] Due to these cross edges 13-1, 13-2, 13-3, and 13-4, the cross section of the core 8 in the circumferential direction 17 of the solid carbide end mill 1 is reduced in a locally restricted manner between the cutting edges 4, 5, 6, and 7.

[0072] The cross edges 13-1, 13-2, 13-3, and 13-4 are each formed as gaps, which are produced, for example, by grinding in chip removal grooves 14-1, 14-2, 14-3, and 14-4 between the respective cutting edges 4, 5, 6, and 7 in the region of the end side 12 of the cutting region 3 and approach the rotational axis 9 of the solid carbide end mill 1 in the direction from the fastening part 2 to the end side 12 of the cutting region 3 (cross edge 13-1 to chip removal groove 14-1, cross edge 13-2 to chip removal groove 14-2, cross edge 13-3 to chip removal groove 14-3, and cross edge 13-4 to chip removal groove 14-4).

[0073] In the present text, the chisel edges 13-1, 13-2, 13-3, and 13-4 are selected such that the first chisel edge 13-1 and the third chisel edge 13-3 are (geometrically) identical to each other and (geometrically) different from the second chisel edge 13-2 and the fourth chisel edge 13-4 (the second chisel edge and the fourth chisel edge are (geometrically) identical to each other in turn).

[0074] In addition, the first chisel edge 13-1 and the third chisel edge 13-3 will each have a (chisel edge) angle 20 in the range from 30° to 45°, currently about 35° (see Figure 4-1 ), and the second chisel edge 13-2 and the fourth chisel edge 13-4 will each have a (chisel edge) angle 21 in the range from 35° to 50°, currently about 42.5° (see Figure 4-2 ) (always with respect to the normal plane of the rotation axis of the end mill (e.g., the proximal side)).

[0075] In addition, the first chisel edge 13-1 and the third chisel edge 13-3 will each have a (chisel edge) opening angle 22 in the range from 30° to 50°, currently about 40°, and the second chisel edge 13-2 and the fourth chisel edge 13-4 will each have a (chisel edge) opening angle 23 in the range from 40° to 60°, currently about 42.5° (this opening angle is always the angle between the sides of the chisel edge in a top view looking at the end side of the end mill) (see Figure 3 ).

[0076] When visualized in the top view looking at the end side 12 as shown in Figure 3 , the respective sides 26 of the chisel edges 13-1 / 13-3 and 13-2 / 13-4 converge at angles 22 and 23, which appear as 40° and 42.5° respectively in the perspective view, where the ends in the direction of the rotation axis 9 are in each case rounded (rounding 27), the radius of which (by way of example here) corresponds to 0.075 to 0.125 times the cutting area diameter 28 (for the chisel edges 13-1 and 13-3) and 0.1 to 0.3 times the cutting area diameter 28 (for the chisel edges 13-2 and 13-4).

[0077] In simplified and visualized terms, this means that the first transverse edge 13-1 and the third transverse edge 13-3, which are respectively located on the longer proximal side cutting edge 11, are (geometrically) identical, just as the second transverse edge 13-2 and the fourth transverse edge 13-4, which are respectively located on the shorter proximal side cutting edge 11, are (geometrically) identical, where the second transverse edge 13-2 and the fourth transverse edge 13-4 respectively "extend more steeply and with a greater (transverse edge) opening angle" than the first transverse edge 13-1 and the third transverse edge 13-3. In this way, two corresponding different transverse edges 13-1 and 13-3, and 13-2 and 13-4, alternate with each other in the circumferential direction 17 on the end side 12 of the end mill.

[0078] Furthermore, what the solid carbide end mill 1 provides is that all the transverse edges 13-1, 13-2, 13-3 and 13-4 starting at the end side (12) basically terminate at the same axial height (19) in the cutting area 3, so as to ensure that the chips are respectively discharged evenly into the corresponding chip removal grooves 14-1, 14-2, 14-3 and 14-4.

[0079] As is particularly prominent in Figure 1 In the present case, the chip removal grooves 14-1, 14-2, 14-3 and 14-4 are respectively arranged between two adjacent (in the circumferential direction 17) cutting edges 4 and 5, or 5 and 6, or 6 and 7, or 7 and 4 of the teeth 4, 5, 6 and 7 and are used together with the transverse edges 13-1, 13-2, 13-3 and 13-4 to discharge the chips generated by the main cutting edges 10 and the side cutting edges 11 of the cutting edges 4, 5, 6 and 7.

[0080] This means that the chip removal grooves 14 and the transverse edges 13 respectively form a chip removal space 16 at the cutting edges / teeth 4, 5, 6 and 7 in each case.

[0081] Due to the transverse edges 13-1, 13-2, 13-3 and 13-4, the cross-sections of the chip removal grooves 14-1, 14-2, 14-3 and 14-4 are enlarged in the region of the end side 12 of the cutting area 3, and as a result, the chips, especially the chips from the central proximal region of the (proximal side) side cutting edge 11, can be transported away particularly well (see the introductory note on the boring operation and the balance characteristics of the transverse edge in the context of the present invention).

[0082] All the cutting edges / teeth 4, 5, 6 and 7 respectively have a clearance angle 24 of 5° to 7°, especially 6°, which means that the angle between the end face 15 of each side cutting edge 11 and the (normal) plane perpendicular to the rotation axis 9 is respectively 5° to 7°, or especially 6°.

[0083] Likewise, all cutting edges / teeth 4, 5, 6, and 7 each have an (end) rake angle 25 of 2° to 4°, in particular currently approximately 3°, which means that the chip space proximal (end) face of each secondary cutting edge 11 provides a rake angle 25 of between 2° and 4°, in particular approximately 3°, relative to a plane parallel to the rotational axis 9 of the end mill.

[0084] As can also be derived from Figure 2 (highlighted by the auxiliary lines drawn in this figure), the cutting edges 4, 5, 6, and 7 (the secondary cutting edges 11 together with the main cutting edge 10) are arranged unevenly in the circumferential direction 17 of the solid carbide end mill 1, which promotes the stability of the cutting edges 4, 5, 6, and 7 and reduces vibration.

[0085] As stated, this non-uniformity relates to the normal plane (relative to the rotational axis 9), which is located approximately 0.5*D (D = diameter of the cutting area 3 of the solid carbide end mill 1) below the end side 12 in the axial direction 19 (in the direction of the rotational axis 9).

[0086] In this way, the first cutting edge 4 and the third cutting edge 6, and the second cutting edge 5 and the fourth cutting edge 7 (at the end side 12) are approximately opposite each other or approximately diametrically opposite each other, but the angle between the first cutting edge 4 and the adjacent (in the clockwise direction) fourth cutting edge 7 and the angle between the third cutting edge 6 and the adjacent (in the clockwise direction) second cutting edge 5 are each designed to be less than 90° (first pitch 29), particularly preferably approximately 82.5°. This means that the angle between the fourth cutting edge 7 and the adjacent (in the clockwise direction) third cutting edge 6 and the angle between the second cutting edge 5 and the adjacent (in the clockwise direction) first cutting edge 4 are greater than 90° and preferably approximately 97.5° (second pitch 30).

[0087] Since the current helix angle (first helix angle 31) of the cutting edges 4 and 6 of approximately 36.5° is different from the current helix angle (second helix angle 32) of the cutting edges 5 and 7 of approximately 38°, this results in the cutting edges 4, 5, 6, and 7 having unequal pitches in the region of the axial extent 19 of the chisel edges 13-1, 13-2, 13-3, and 13-4, in almost all axial 19 normal planes with respect to the rotational axis 9 of the solid carbide end mill 1 (this unequal pitch of the cutting edges 4, 5, 6, and 7 in the cutting area 3 varies along the rotational axis 9).

[0088] This unequal pitch of the cutting edges 4, 5, 6, and 7 (by virtue of its favorable stability) is particularly relevant in the region of the end side 12 of the cutting region 3, because the cross-section of the core 8 of the solid carbide end mill 1 is reduced most significantly here due to the chisel edges 13-1, 13-2, 13-3, and 13-4 in order to form and define two long secondary cutting edges 11 (which essentially reach the rotational axis 9) and in order to enable the chips to be discharged from the secondary cutting edges 11 in the axial direction 19 close to the rotational axis 9.

[0089] This is particularly important in boring operations, because in the case of boring a hole in a solid material without a pilot hole, material must be removed subtractively over the entire cross-section of the cutting region 3.

[0090] Furthermore, in the solid carbide end mill 1 it is also provided that at least the cutting region 3 is coated, in particular with a coating 33, the coating thickness of which lies between 0.0010 mm and 0.006 mm, in particular between 0.0015 mm and 0.005 mm, especially between 0.0018 mm and 0.004 mm.

[0091] Although the invention has been shown and described in detail by means of preferred exemplary embodiments, the invention is not limited to the disclosed examples, and other variants can be derived from these examples without departing from the scope of protection of the invention.

[0092] List of reference numerals:

[0093] 1 Solid carbide end mill

[0094] 2 Clamping part

[0095] 3 Cutting region

[0096] 4 First cutting edge / first (long) tooth

[0097] 5 Second cutting edge / second (short) tooth

[0098] 6 Third cutting edge / third (long) tooth

[0099] 7 Fourth cutting edge / fourth (short) tooth

[0100] 8 (Cylindrical) core

[0101] 9 Rotational axis

[0102] 10 (Circumferential) main cutting edge

[0103] 11 (Proximal side) secondary cutting edge

[0104] 12 The end side of the solid carbide end mill or the end side of the cutting area 13 or 13-1, 13-2, 13-3, 13-4 chisel edge

[0105] 14 or 14-1, 14-2, 14-3, 14-4 chip removal groove

[0106] 15 End face

[0107] 16 or 16-1, 16-2, 16-3, 16-4 chip removal space

[0108] 17 Circumferential direction

[0109] 18 Corner bevel

[0110] 19 Axial direction, "axial"

[0111] 20 The (chisel edge) angle between the first chisel edge 13-1 and the third chisel edge 13-3 21 The (chisel edge) angle between the second chisel edge 13-2 and the fourth chisel edge 13-4 22 The (chisel edge) opening angle between the first chisel edge 13-1 and the third chisel edge 13-3 23 The (chisel edge) opening angle between the second chisel edge 13-2 and the fourth chisel edge 13-4

[0112] 24 Relief angle

[0113] 25 (Positive) rake angle

[0114] 26 Side face

[0115] 27 Fillet

[0116] 28 Cutting area diameter

[0117] 29 First angular pitch

[0118] 30 Second angular pitch

[0119] 31 First helix angle

[0120] 32 Second helix angle

[0121] 33 Coating

[0122] α Corner bevel angle.

Claims

1. An end mill having a fastening portion and a cutting area, wherein: The cutting region is formed by a core and at least two cutting edges which are arranged around the core and extend helically around the axis of rotation of the end mill, each of the cutting edges having in each case a circumferential main cutting edge and a secondary cutting edge on the end side of the cutting region, wherein at least one first chisel edge of the core between two mutually adjacent cutting edges and at least one second chisel edge between two mutually adjacent cutting edges are provided on the end side of the cutting region, It is characterized in that The first chisel edge is designed to be different from the second chisel edge, the first chisel edge has a (chisel edge) angle of 30° to 45°, and the second chisel edge has a (chisel edge) angle of 35° to 50°, and the first chisel edge has an opening angle of 30° to 50°, and the second chisel edge has an opening angle of 40° to 60°.

2. An end mill according to any one of the preceding claims, It is characterized in that The first chisel edge has a (chisel edge) angle of 32° to 38°, in particular approximately 35°, and the second chisel edge has a (chisel edge) angle of 39° to 46°, in particular approximately 42.5°.

3. An end mill according to any one of the preceding claims, It is characterized in that The first chisel edge has an opening angle of 35° to 45°, in particular approximately 40°, and the second chisel edge has an opening angle of 41° to 50°, in particular approximately 42.5°.

4. End mill according to one of the preceding claims, It is characterized in that A plurality of the first chisel edges and the second chisel edges are provided, wherein the first chisel edges and the second chisel edges are alternately arranged with each other in a circumferential direction on the end side of the end mill.

5. End mill according to one of the preceding claims, It is characterized in that The proximal side secondary cutting edge of the first cutting edge of the first tooth is longer than the proximal side secondary cutting edge of the second cutting edge of the second tooth, wherein the first chisel edges jointly form a chip space of the first cutting edge or the first tooth, and the second chisel edges jointly form a chip space of the second cutting edge or the second tooth.

6. End mill according to the preceding claim, It is characterized in that A plurality of the first teeth or the first cutting edges having longer proximal side secondary cutting edges and a chip space having the first chisel edge, and a plurality of the second teeth or the second cutting edges having shorter proximal side secondary cutting edges and a chip space having the second chisel edge, wherein the longer proximal side secondary cutting edges are alternated with their corresponding first chisel edges and the shorter proximal side secondary cutting edges are alternated with their corresponding second chisel edges on the end side of the end mill in the circumferential direction of the cutting portion.

7. End mill according to one of the preceding claims, It is characterized in that The first chisel edge and the second chisel edge, starting from the end side, end essentially at the same axial height in the cutting region.

8. End mill according to one of the preceding claims, It is characterized in that The cutting area includes a total of four cutting edges, of which the first cutting edge and the third cutting edge, and the second cutting edge and the fourth cutting edge are substantially opposite to each other or approximately diametrically opposite to each other, and the first chisel edge is arranged between the first cutting edge and the second cutting edge and between the third cutting edge and the fourth cutting edge, and the second chisel edge is arranged between the second cutting edge and the third cutting edge and between the fourth cutting edge and the first cutting edge.

9. End mill according to one of the preceding claims, It is characterized in that The cutting edges are unevenly distributed in the circumferential direction of the cutting region.

10. End mill according to one of the preceding claims, It is characterized in that In the circumferential direction of the cutting area and at a predefined axial height in the cutting area, the angle between the first cutting edge and the second cutting edge and the angle between the third cutting edge and the fourth cutting edge are each greater than 90°, in particular about 97.5°, and / or the angle between the second cutting edge and the third cutting edge and the angle between the fourth cutting edge and the first cutting edge are each less than 90°, in particular about 82.5°. In particular, the predefined axial height is the end face of the end mill (corresponding to a height of 0 mm) or approximately 0.5*D (D=diameter of the cutting area) axially below the end face of the end mill.

11. End mill according to one of the preceding claims, It is characterized in that The circumferential main cutting edge of the cutting edge has different helix angles, in particular, the circumferential main cutting edge of the cutting edge has a first helix angle alternating with a second helix angle in a circumferential direction of the cutting region, the second helix angle being different from the first helix angle.

12. End mill according to one of the preceding claims, It is characterized in that The end face of the cutting edge on the secondary cutting edge, in particular the end face of each cutting edge, has a clearance angle of between 5° and 7°, in particular about 6°, relative to a plane perpendicular to the axis of rotation of the end mill.

13. End mill according to one of the preceding claims, It is characterized in that The secondary cutting edge, in particular the chip space proximal (end) face of each secondary cutting edge, has a rake angle of between 2° and 4°, in particular about 3°, relative to a plane parallel to the axis of rotation of the end mill.

14. End mill according to one of the preceding claims, It is characterized in that The proximal minor cutting edge and the circumferential main cutting edge of the cutting edge merge into one another via a corner bevel, in particular a corner bevel having a corner bevel angle of 45°.

15. End mill according to one of the preceding claims, It is characterized in that The core has a cylindrical design.

16. End mill according to one of the preceding claims, It is characterized in that At least the cutting zone is coated, in particular with a coating having a layer thickness of between 0.0010 mm and 0.006 mm, in particular between 0.0015 mm and 0.005 mm, in particular between 0.0018 mm and 0.004 mm.

17. End mill according to one of the preceding claims, It is characterized in that The end mill is a solid carbide end mill.

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