An end mill

Abstract

The application relates to the technical field of cutters, and discloses a ball end mill, which is characterized in that N peripheral cutting edges are arranged, a first edge gap and a second bottom end flank are arranged to form M bottom end cutting edges, and M is less than N, that is, the number of the bottom end cutting edges is less than the number of the peripheral cutting edges; the first edge gap is matched with a chip removal groove arranged on the bottom end cutting part to remove chips, the bottom end cutting part has a larger chip removal space, thereby avoiding chip accumulation and facilitating cutter heat dissipation; the first edge gap can reduce the manufacturing difficulty of the ball end mill; in addition, by limiting M to be less than N, the structural strength of the bottom end cutting part can be improved, the wear speed of the cutting edges is slowed down, the cutting performance of the ball end mill is improved, and the service life of the ball end mill is prolonged.

Description

An end mill Technical Field

[0001] This invention relates to the field of cutting tool technology, and more particularly to an end mill. Background Technology

[0002] When roughing deep cavities with bevels, the conventional method is to use tapered end mills. However, because tapered end mills have a small cutting edge diameter, their chip space is also small. This inevitably leads to chip accumulation during cutting, preventing the cutting heat from dissipating in time, reducing the strength of the cutting edge, causing rapid wear of the cutting edge, and thus reducing the tool's service life.

[0003] Therefore, there is an urgent need for an end mill to solve the above-mentioned technical problems. Summary of the Invention

[0004] The purpose of this invention is to provide an end mill that can increase the chip space at the front end of the end mill, thereby ensuring smooth chip removal and extending the tool's service life.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] An end mill includes a cutter head with N chip removal grooves extending helically along its axial direction, where N ≥ 3. The surface of each chip removal groove facing the cutting rotation direction is a rake face, which intersects with the outer peripheral surface of the cutter head to form a cutting edge. The outer peripheral wall of the cutter head in contact with the cutting edge forms a flank face. The cutter head includes a circumferential cutting portion and a bottom cutting portion connected to one end of the circumferential cutting portion. The N cutting edges include N circumferential cutting edges on the circumferential cutting portion and M bottom cutting edges on the bottom cutting portion, with each bottom cutting edge corresponding to one of the circumferential cutting edges. The flank face includes a circumferential flank face on the circumferential cutting portion and a first bottom flank face on the bottom cutting portion.

[0007] A first cutting edge is provided between two adjacent chip removal grooves, and the first cutting edge is located at the bottom cutting part; along the circumference of the cutter head, one end of the first cutting edge intersects with the inner wall of one of the two adjacent chip removal grooves through the second bottom flank face, and the other end intersects with the inner wall of the other chip removal groove, such that M < N; along the axial direction of the cutter head, both ends of the third flank face and both ends of the first cutting edge intersect with the first bottom flank face and the circumferential flank face, respectively.

[0008] As a preferred technical solution for the above-mentioned end mill, the first cutting clearance is a plane and is connected to the chip removal groove through an arc surface.

[0009] As a preferred technical solution of the above-mentioned end mill, the outer contour of the bottom cutting part is hemispherical with a radius of R, the second bottom flank face intersects the circumferential cutting edge at point P1, and the first cutting edge clearance intersects the circumferential flank face to form an intersection line;

[0010] The central axis of the cutter head intersects the end face of the bottom cutting part away from the circumferential cutting part at point Q. Along the axial direction of the cutter head, the maximum distance between point P1 and point Q is L1, and the maximum distance between the intersecting line and point Q is L2, where L1 = L2 = R.

[0011] As a preferred technical solution for the above-mentioned end mill, M≥2 and N=2M, the circumferential cutting edge includes M first circumferential cutting edges and M second circumferential cutting edges, the first circumferential cutting edges and the second circumferential cutting edges are arranged alternately along the circumference of the cutter head; the first circumferential cutting edges are connected to the bottom cutting edges in a one-to-one correspondence, and the second bottom flank face is connected to the second circumferential cutting edges in a one-to-one correspondence.

[0012] As a preferred technical solution of the above-mentioned end mill, the first bottom relief face includes a bottom relief face one and a bottom relief face two. The bottom relief face one, the bottom relief face two and the second bottom relief face are connected sequentially along the circumference of the cutter head. The bottom relief face one is connected to the bottom cutting edge.

[0013] The angle between the first bottom flank face and the tangent of the bottom cutting edge is β1, 0°≤β1≤40°; the angle between the second bottom flank face and the tangent of the bottom cutting edge is β2, β1≤β2≤45°; the angle between the second bottom flank face and the tangent of the bottom cutting edge is β3, 20°≤β3≤55°, β2≤β3.

[0014] As a preferred technical solution of the above-mentioned end mill, a second cutting edge is provided inside the chip removal groove that is connected to the first cutting edge, and the second cutting edge is located at the end of the bottom cutting part away from the circumferential cutting part.

[0015] Along the circumference of the cutter head, the two ends of the second cutting gap intersect with the first cutting gap and the bottom cutting edge, respectively; let the plane perpendicular to the axial direction of the cutter head be the first cutting surface, and the intersection line of the first cutting surface and the second cutting gap be an arc.

[0016] As a preferred technical solution of the above-mentioned end mill, the plane perpendicular to the circumferential cutting edge is defined as the second cutting surface. The intersection line between the circumferential flank face and the second cutting surface includes a first line segment, a second line segment, and a third line segment connected in sequence. The intersection point of the circumferential cutting edge and the second cutting surface is the endpoint of one end of the first line segment.

[0017] The angle between the first line segment and the tangent of the circumferential cutting edge is the first circumferential back angle θ1, the angle between the second line segment and the tangent of the circumferential cutting edge is the second circumferential back angle θ2, and the angle between the third line segment and the tangent of the circumferential cutting edge is the third circumferential back angle θ3, where θ1 < θ2 < θ3, 2° ≤ θ1 ≤ 20°, 15° ≤ θ2 ≤ 45°, and 20° ≤ θ3 ≤ 55°.

[0018] As a preferred embodiment of the above-mentioned end mill, the diameter of the circumferential cutting part is D, and the minimum distance between any cross section of the chip removal groove and the central axis of the cutter head is r, 0.25D≤r≤0.4D; the cross section of the chip removal groove is perpendicular to the axial direction of the cutter head.

[0019] As a preferred technical solution of the above-mentioned end mill, it also includes a tool holder, which is connected to the circumferential cutting part and located at the end of the circumferential cutting part away from the bottom cutting part;

[0020] The tool holder is provided with an axial cooling channel extending along its axis, and the bottom cutting part is provided with at least two bottom cooling channels arranged circumferentially therebetween; one end of the axial cooling channel extends to the end face of the tool holder away from the circumferential cutting part, and the other end extends to the bottom cutting part; all the bottom cooling channels converge at one end of the axial cooling channel at a first position, and the other end penetrates the inner wall of the chip removal groove at a second position.

[0021] Along the axial direction of the cutter head, the distance between the first position and the end of the bottom cutting portion away from the circumferential cutting portion is a, and the distance between the second position and the end of the bottom cutting portion away from the circumferential cutting portion is b, where a > b.

[0022] As a preferred technical solution for the above-mentioned end mill, the diameter of the axial cooling channel is d1, 0.05D≤d1≤0.2D, and the diameter of the bottom cooling channel is d2, 0.03D≤d2≤0.15D.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: The end mill provided by the present invention has N circumferential cutting edges and M bottom cutting edges formed by a first cutting clearance and a second bottom flank face, such that M < N. That is, the number of bottom cutting edges is less than the number of circumferential cutting edges. The first cutting clearance is used in conjunction with the chip evacuation groove located on the bottom cutting part for chip removal, so that the bottom cutting part has a larger chip removal space, thereby avoiding chip accumulation and facilitating tool heat dissipation. Moreover, the first cutting clearance can reduce the manufacturing difficulty of the end mill. In addition, by limiting M < N, the structural strength of the bottom cutting part can be improved, the wear rate of the cutting edges can be slowed down, thereby improving the cutting performance of the end mill and extending the service life of the end mill. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of the present invention and these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of the structure of the end mill provided in an embodiment of the present invention;

[0026] Figure 2 is a front view of the end mill provided in an embodiment of the present invention;

[0027] Figure 3 is a side view of the end mill provided in an embodiment of the present invention;

[0028] Figure 4 is a partial structural schematic diagram of the end mill provided in an embodiment of the present invention;

[0029] Figure 5 is a partial structural schematic diagram of the end mill provided in an embodiment of the present invention;

[0030] Figure 6 is a partial structural schematic diagram of the end mill provided in an embodiment of the present invention;

[0031] Figure 7 is a sectional view along the BB direction of Figure 6;

[0032] Figure 8 is a sectional view along line AA of Figure 6.

[0033] In the picture:

[0034] 1. Circumferential cutting section; 111. First circumferential cutting edge; 112. Second circumferential cutting edge; 12. Circumferential flank face; 131. First line segment; 132. Second line segment; 133. Third line segment; 14. Circumferential rake face;

[0035] 2. Bottom cutting section; 21. Bottom cutting edge; 22. Bottom flank face one; 23. Bottom flank face two;

[0036] 3. Chip removal groove; 4. First cutting edge clearance; 5. Second cutting edge clearance; 6. Second bottom flank face; 7. Circular arc surface;

[0037] 100, cutter head; 200, cutter holder; 300, axial cooling channel; 400, bottom cooling channel. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] As shown in Figures 1 to 5, an embodiment of the present invention provides an end mill, which includes a cutter head 100. The cutter head 100 has N chip removal grooves 3 extending helically along its axial direction, where N ≥ 3. The surface of the chip removal grooves 3 facing the cutting rotation direction is the rake face. The rake face intersects with the outer peripheral surface of the cutter head 100 to form a cutting edge, and the outer peripheral wall of the cutter head 100 in contact with the cutting edge forms the flank face. The cutting edge is used for cutting, and the chip removal grooves 3 are used to promptly remove chips during end mill operation to ensure normal cutting. It should be noted that this end mill is mainly used for rough machining of workpieces.

[0043] The cutting head 100 includes a circumferential cutting section 1 and a bottom cutting section 2 connected to one end of the circumferential cutting section 1. N cutting edges include N circumferential cutting edges on the circumferential cutting section 1 and M bottom cutting edges 21 on the bottom cutting section 2, with each bottom cutting edge 21 corresponding to one of the circumferential cutting edges. The flank face includes a circumferential flank face 12 on the circumferential cutting section 1 and a first bottom flank face on the bottom cutting section 2. The rake face includes a circumferential rake face 14 on the circumferential cutting section 1 and a bottom rake face on the bottom cutting section 2.

[0044] Optionally, as shown in Figure 2, the tangential direction of the circumferential cutting edge is arranged at an angle θ to the axial direction of the tool head 100, where 0 < θ ≤ 50°. For example, θ can be any value selected from 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, and 50°. It should be noted that the chip removal groove 3, like the circumferential cutting edge, has a certain taper to the axial direction of the tool head 100.

[0045] A first cutting edge 4 is provided between two adjacent chip removal grooves 3. The first cutting edge 4 is located at the bottom cutting part 2. Along the circumference of the cutter head 100, one end of the first cutting edge 4 intersects with the inner wall of one of the two adjacent chip removal grooves 3 through the second bottom flank face 6, and the other end intersects with the inner wall of the other chip removal groove 3, such that M < N. Along the axial direction of the cutter head 100, both ends of the third flank face and both ends of the first cutting edge 4 intersect with the first bottom flank face and the circumferential flank face 12, respectively.

[0046] This end mill has N circumferential cutting edges and a first cutting clearance 4 and a second bottom relief face 6 to form M bottom cutting edges 21, such that M < N. That is, the number of bottom cutting edges 21 is less than the number of circumferential cutting edges. The first cutting clearance 4, in conjunction with the chip vent 3 located on the bottom cutting section 2, facilitates chip removal, giving the bottom cutting section 2 a larger chip removal space, thereby preventing chip accumulation and promoting tool heat dissipation. Moreover, the first cutting clearance 4 can reduce the manufacturing difficulty of the end mill. In addition, by limiting M < N, the structural strength of the bottom cutting section 2 can be improved, the wear rate of the cutting edges can be slowed down, thereby improving the cutting performance of the end mill and extending its service life.

[0047] In some embodiments, as shown in Figures 2 and 3, M ≥ 2 and N = 2M, the circumferential cutting edge includes M first circumferential cutting edges 111 and M second circumferential cutting edges 112, which are arranged alternately along the circumference of the tool head 100. The first circumferential cutting edges 111 are connected to the bottom cutting edges 21 in a one-to-one correspondence, and the second bottom flank face 6 is connected to the second circumferential cutting edges 112 in a one-to-one correspondence. This arrangement can ensure chip removal while making the cutting amount uniform among different bottom cutting edges 21, thus reducing the difference in cutting amount between different bottom cutting edges 21.

[0048] For example, M=2 and N=4, that is, there are four circumferential cutting edges and two bottom cutting edges 21, and correspondingly, there are four chip removal grooves 3. In other embodiments, there may be two, three, five or more chip removal grooves 3, and the number of circumferential cutting edges and the number of chip removal grooves 3 are equal.

[0049] In some embodiments, the first cutting clearance 4 is planar and connects to the chip removal groove 3 via an arc surface 7. Compared to the first cutting clearance 4 with an arc surface, the planar first cutting clearance 4 allows the bottom cutting portion 2 to have a larger chip removal space, avoiding chip accumulation and facilitating tool heat dissipation.

[0050] In some embodiments, as shown in FIG4, the outer contour of the bottom cutting portion 2 is hemispherical with a radius of R. The second bottom flank face 6 intersects the circumferential cutting edge at point P1, and the first cutting clearance 4 intersects the circumferential flank face 12 to form an intersection line. The central axis of the tool head 100 intersects the end face of the bottom cutting portion 2 away from the circumferential cutting portion 1 at point Q. Along the axial direction of the tool head 100, the maximum distance between point P1 and point Q is L1, and the maximum distance between the intersection line and point Q is L2, where L1 = L2 = R. Specifically, along the axial direction of the tool head 100, the point furthest from point Q on the intersection line is point P2. In other words, along the axial direction of the tool head 100, the distance between point P2 and point Q is L2. By limiting L1 = L2 = R, not only can the integrity of the circumferential cutting edge be guaranteed, but the bottom cutting portion 2 can also have a larger chip removal space.

[0051] In some embodiments, as shown in FIG5, the first bottom flank face includes a bottom flank face 22 and a bottom flank face 23. The bottom flank face 22, the bottom flank face 23 and the second bottom flank face 6 are connected sequentially along the circumference of the cutter head 100. The bottom flank face 22 is connected to the bottom cutting edge 21. The angle between the tangent of the bottom flank face 22 and the bottom cutting edge 21 is β1, 0°≤β1≤40°. The angle between the tangent of the bottom flank face 23 and the bottom cutting edge 21 is β2, β1≤β2≤45°. The angle between the tangent of the second bottom flank face 6 and the bottom cutting edge 21 is β3, 20°≤β3≤55°, β2≤β3.

[0052] For example, β1 can be selected from any value among 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, and 40°, and β3 can be selected from any value among 20°, 25°, 30°, 35°, 40°, 45°, 50°, and 55°. When selecting β2, provided that β2 is not greater than 45° and β1≤β2≤β3, the value of β2 can be determined according to actual needs.

[0053] In some embodiments, as shown in Figures 4 and 5, a second cutting edge 5 is provided inside the chip removal groove 3 connected to the first cutting edge 4. The second cutting edge 5 is located at the end of the bottom cutting part 2 away from the circumferential cutting part 1. Along the circumference of the cutter head 100, both ends of the second cutting edge 5 intersect with the first cutting edge 4 and the bottom cutting edge 21, respectively. The plane perpendicular to the axial direction of the cutter head 100 is defined as the first cutting plane, and the intersection line of the first cutting plane and the second cutting edge 5 is an arc.

[0054] By setting a second cutting clearance 5 and restricting the intersection line to an arc, the chip curling diameter of the end mill can be increased during the cutting process. At the same time, the second cutting clearance 5 can also provide a larger chip removal space for the bottom cutting part 2, allowing the cutting to avoid the tip of the end mill and reducing tip wear. Moreover, the arc shape of the intersection line makes the second cutting clearance 5 a circular arc surface, which can better alleviate stress concentration during cutting.

[0055] In some embodiments, as shown in Figures 6 and 7, the plane perpendicular to the circumferential cutting edge is designated as the second cutting surface. The intersection line between the circumferential relief face 12 and the second cutting surface includes a first line segment 131, a second line segment 132, and a third line segment 133 connected sequentially. The intersection point of the circumferential cutting edge and the second cutting surface is the endpoint of one end of the first line segment 131. The angle between the first line segment 131 and the tangent of the circumferential cutting edge is the first circumferential relief angle θ1, the angle between the second line segment 132 and the tangent of the circumferential cutting edge is the second circumferential relief angle θ2, and the angle between the third line segment 133 and the tangent of the circumferential cutting edge is the third circumferential relief angle θ3. It should be noted that the number of line segments included in the intersection line between the circumferential relief face 12 and the second cutting surface is not limited to three; it can also include two, four, or more segments, depending on actual needs. Examples will not be provided here.

[0056] If the first circumferential clearance angle θ1 is too small, the flank face will easily interfere with the machined surface during rotary cutting; if the first circumferential clearance angle θ1 is too large, the cutting strength of the end mill will be too low, and chipping will easily occur during cutting. Therefore, optionally, 2°≤θ1≤20°. For example, θ1 can be selected from any angle value of 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, and 20°.

[0057] If the second and third circumferential clearance angles θ2 and θ3 are too small, the clearance space of the flank face during rotary cutting is too small, which also reduces the chip space of the chip evacuation groove 3, making it difficult for chips to be discharged. If the second and third circumferential clearance angles θ2 and θ3 are too large, the cutting strength of the end mill is too low, making it prone to chipping during cutting, and it is also prone to interfering with other cutting edges during actual machining. Therefore, optionally, 15°≤θ2≤45° and 20°≤θ3≤55° are suitable. For example, θ2 can be selected from any angle value among 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, and 45°. θ3 can be any angle value among 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29°, 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, and 55°.

[0058] In some embodiments, as shown in FIG8, the diameter of the circumferential cutting part 1 is D, and the minimum distance between any cross-section of the chip removal groove 3 and the central axis of the cutter head 100 is r, where 0.25D≤r≤0.4D; the cross-section of the chip removal groove 3 is perpendicular to the axial direction of the cutter head 100. If the distance r is too small, the strength of the cutter head 100 decreases; if the distance r is too large, the chip removal space decreases, and the chip removal performance decreases. By limiting 0.25D≤r≤0.4D, the structural strength of the cutter head 100 can be guaranteed while ensuring that the chip removal performance of the cutter head 100 meets the requirements.

[0059] For example, r can be selected from any value among 0.25D, 0.26D, 0.27D, 0.28D, 0.29D, 0.3D, 0.31D, 0.32D, 0.33D, 0.34D, 0.35D, 0.36D, 0.37D, 0.38D, 0.39D, and 0.4D.

[0060] In some embodiments, as shown in FIG2, the end mill further includes a shank 200, which is connected to the circumferential cutting portion 1 and located at the end of the circumferential cutting portion 1 away from the bottom cutting portion 2; the shank 200 is provided with an axial cooling channel 300 extending along its axial direction, and the bottom cutting portion 2 is provided with at least two bottom cooling channels 400 arranged circumferentially; one end of the axial cooling channel 300 extends to the end face of the end of the shank 200 away from the circumferential cutting portion 1, and the other end extends to the bottom cutting portion 2; all bottom cooling channels 400 are joined at the axial cooling channel 300 at a first position and penetrate the inner wall of the chip removal groove 3 at a second position.

[0061] The axial cooling channel 300 guides the coolant into the bottom cooling channel 400, and the coolant flows out from the bottom cooling channel 400. By providing at least two bottom cooling channels 400 arranged circumferentially along the bottom cutting portion 2 and connecting the bottom cooling channels 400 to the chip removal groove 3, the cooling effect of the coolant on the bottom cutting portion 2 can be guaranteed. For example, each chip removal groove 3 is equipped with one bottom cooling channel 400.

[0062] In some embodiments, the orifice diameter of the axial cooling channel 300 is d1, where 0.05D≤d1≤0.2D, and the orifice diameter of the bottom cooling channel 400 is d2, where 0.03D≤d2≤0.15D. By limiting the orifice diameters of the axial cooling channel 300 and the bottom cooling channel 400, not only can the cooling effect of the cutting head 100 be ensured, but also the structural strength of the cutting head 100 can be ensured, and the wear rate of the circumferential cutting edge and the bottom cutting edge 21 can be reduced.

[0063] For example, d1 can be any value selected from 0.05D, 0.06D, 0.07D, 0.08D, 0.09D, 0.1D, 0.11D, 0.12D, 0.13D, 0.14D, 0.15D, 0.16D, 0.17D, 0.18D, 0.19D, and 0.2D. d2 can be any value selected from 0.03D, 0.04D, 0.05D, 0.06D, 0.07D, 0.08D, 0.09D, 0.1D, 0.11D, 0.12D, 0.13D, 0.14D, and 0.15D.

[0064] In some embodiments, along the axial direction of the cutter head 100, the distance between the first position and the end of the bottom cutting portion 2 away from the circumferential cutting portion 1 is 'a', and the distance between the second position and the end of the bottom cutting portion 2 away from the circumferential cutting portion 1 is 'b'; a > b. This arrangement allows the bottom cooling channel 400 to be axially inclined relative to the cutter head 100, which is beneficial for improving the cooling effect of the bottom cutting portion 2.

[0065] In some embodiments, the cutter head 100 and the tool holder 200 are integrally formed. This configuration reduces the machining cost of the end mill, eliminates the need for assembly after machining, and improves the production efficiency of the end mill. Exemplarily, the tool holder 200 has a cylindrical structure, which facilitates its mounting on machine tools and is suitable for various fixtures.

[0066] In some embodiments, as shown in FIG2, the helix angle of the circumferential cutting edge is σ, where 0°<σ≤50°; for example, the helix angle σ can be selected from any angle value among 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, and 50°.

[0067] In some embodiments, the end mill is made of any one or at least two of high-speed steel, cemented carbide, cubic boron nitride, and polycrystalline diamond to ensure the cutting performance of the end mill and extend its service life. It should be noted that when the end mill is made of at least two of high-speed steel, cemented carbide, cubic boron nitride, and polycrystalline diamond, the specific composition is prior art and will not be described in detail here.

[0068] The end mill provided in the embodiments of the present invention is particularly suitable for machining deep cavities with bevels. It employs a circumferential cutting edge with a taper of θ, which helps ensure the rigidity of the tool. Furthermore, bottom-end cutting with a spherical outer contour cannot be used for profile milling. The number of bottom-end cutting edges 21 is less than the number of circumferential cutting edges. Having a larger number of circumferential cutting edges ensures the machining efficiency of the end mill, while having a smaller number of bottom-end cutting edges 21 facilitates chip removal from the bottom cutting section 2. During the cutting process, the space formed by the chip removal groove 3 and the first cutting clearance 4 can accommodate more chips. Compared to having only the chip removal groove 3, the chip removal space can be increased by approximately 150%. Moreover, by combining the axial cooling channel 300 and the bottom-end cooling channel 400 to circulate coolant to cool the cutter head 100, overheating of the cutting edge of the cutter head 100 can be avoided, extending the service life of the end mill.

[0069] Furthermore, the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An end mill, comprising a cutter head (100), wherein the cutter head (100) is provided with N chip removal grooves (3) extending helically along its axial direction, where N ≥ 3; the surface of the chip removal grooves (3) facing the cutting rotation direction is a rake face, the rake face intersects with the outer peripheral surface of the cutter head (100) to form a cutting edge, and the outer peripheral wall of the cutter head (100) in contact with the cutting edge forms a flank face; the cutter head (100) comprises a circumferential cutting portion (1) and a portion connected to the circumferential cutting portion. (1) A bottom cutting portion (2) at one end, wherein the N cutting edges include N circumferential cutting edges provided on the circumferential cutting portion (1) and M bottom cutting edges (21) provided on the bottom cutting portion (2), wherein the bottom cutting edges (21) are connected to the circumferential cutting edges in a one-to-one correspondence; the flank face includes a circumferential flank face (12) provided on the circumferential cutting portion (1) and a first bottom flank face provided on the bottom cutting portion (2); characterized in that, A first cutting edge (4) is provided between two adjacent chip removal grooves (3), and the first cutting edge (4) is located at the bottom cutting part (2); along the circumference of the cutter head (100), one end of the first cutting edge (4) intersects with the inner wall of one of the two adjacent chip removal grooves (3) through the second bottom back face (6), and the other end intersects with the inner wall of the other chip removal groove (3), such that M < N; along the axial direction of the cutter head (100), both ends of the second bottom back face (6) and both ends of the first cutting edge (4) are respectively connected to the first bottom back face and the inner wall of the chip removal groove (3). The circumferential back face (12) intersects; the outer contour of the bottom cutting part (2) is hemispherical with a radius of R, the second bottom back face (6) intersects the circumferential cutting edge at point P1, the first cutting edge (4) intersects the circumferential back face (12) to form an intersecting line; the central axis of the cutter head (100) intersects the end face of the bottom cutting part (2) away from the circumferential cutting part (1) at point Q, along the axial direction of the cutter head (100), the maximum distance between point P1 and point Q is L1, and the maximum distance between the intersecting line and point Q is L2, L1 = L2 = R.

2. The end mill according to claim 1, characterized in that, The first cutting edge (4) is a plane and is connected to the chip removal groove (3) through an arc surface (7).

3. The end mill according to claim 1, characterized in that, M≥2 and N=2M, the circumferential cutting edge includes M first circumferential cutting edges (111) and M second circumferential cutting edges (112), the first circumferential cutting edges (111) and the second circumferential cutting edges (112) are arranged alternately along the circumference of the tool head (100); the first circumferential cutting edge (111) is connected to the bottom cutting edge (21) in a one-to-one correspondence, and the second bottom flank face (6) is connected to the second circumferential cutting edge (112) in a one-to-one correspondence.

4. The end mill according to claim 1, characterized in that, The first bottom relief face includes a bottom relief face one (22) and a bottom relief face two (23). The bottom relief face one (22), the bottom relief face two (23) and the second bottom relief face (6) are connected sequentially along the circumference of the cutter head (100). The bottom relief face one (22) is connected to the bottom cutting edge (21). The angle between the bottom relief face one (22) and the tangent of the bottom cutting edge (21) is β1, 0°≤β1≤40°. The angle between the bottom relief face two (23) and the tangent of the bottom cutting edge (21) is β2, β1≤β2≤45°. The angle between the second bottom relief face (6) and the tangent of the bottom cutting edge (21) is β3, 20°≤β3≤55°, β2≤β3.

5. The end mill according to claim 1, characterized in that, A second cutting edge (5) is provided inside the chip removal groove (3) connected to the first cutting edge (4). The second cutting edge (5) is located at the end of the bottom cutting part (2) away from the circumferential cutting part (1). Along the circumference of the cutter head (100), the two ends of the second cutting edge (5) intersect with the first cutting edge (4) and the bottom cutting edge (21), respectively. The plane perpendicular to the axial direction of the cutter head (100) is defined as the first cutting surface, and the intersection line of the first cutting surface and the second cutting edge (5) is an arc.

6. The end mill according to claim 1, characterized in that, Let the plane perpendicular to the circumferential cutting edge be the second cutting plane. The intersection line between the circumferential back face (12) and the second cutting plane includes a first line segment (131), a second line segment (132), and a third line segment (133) connected in sequence. The intersection point of the circumferential cutting edge and the second cutting plane is the endpoint of one end of the first line segment (131). The angle between the first line segment (131) and the tangent of the circumferential cutting edge is the first circumferential back angle θ1. The angle between the second line segment (132) and the tangent of the circumferential cutting edge is the second circumferential back angle θ2. The angle between the third line segment (133) and the tangent of the circumferential cutting edge is the third circumferential back angle θ3. θ1 < θ2 < θ3, 2° ≤ θ1 ≤ 20°, 15° ≤ θ2 ≤ 45°, and 20° ≤ θ3 ≤ 55°.

7. The end mill according to any one of claims 1 to 6, characterized in that, The diameter of the circumferential cutting part (1) is D, and the minimum distance between any cross section of the chip removal groove (3) and the central axis of the cutting head (100) is r, 0.25D≤r≤0.4D; the cross section of the chip removal groove (3) is perpendicular to the axial direction of the cutting head (100).

8. The end mill according to claim 7, characterized in that, It also includes a tool holder (200), which is connected to the circumferential cutting portion (1) and located at one end of the circumferential cutting portion (1) away from the bottom cutting portion (2); the tool holder (200) is provided with an axial cooling channel (300) extending along its axial direction, and the bottom cutting portion (2) is provided with at least two bottom cooling channels (400) arranged circumferentially; one end of the axial cooling channel (300) extends to the end face of the tool holder (200) away from the circumferential cutting portion (1), and the other end extends to the end face of the tool holder (200) away from the circumferential cutting portion (1). The end extends to the bottom cutting part (2); all the bottom cooling channels (400) converge at one end to the axial cooling channel (300) at a first position, and the other end penetrates the inner wall of the chip removal groove (3) at a second position; along the axial direction of the cutter head (100), the distance between the first position and the end of the bottom cutting part (2) away from the circumferential cutting part (1) is a, and the distance between the second position and the end of the bottom cutting part (2) away from the circumferential cutting part (1) is b, a>b.

9. The end mill according to claim 8, characterized in that, The aperture of the axial cooling channel (300) is d1, 0.05D≤d1≤0.2D, and the aperture of the bottom cooling channel (400) is d2, 0.03D≤d2≤0.15D.

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