End mill

Abstract

The utility model belongs to the technical field of cutters, and discloses an end mill, which is characterized in that bottom blades are distributed on a revolution surface formed by rotation of a 1 / 4 ellipse around a central axis of a cutting part, so that a tool cutting edge angle is gradually and slowly increased in the direction from the center of the end mill to the periphery of the end mill, and one end, connected with a circumferential blade, of each bottom blade can also be used for cutting. And under the same cutting depth, cuttings become thinner and longer, and the thinning cutting effect is better during fast feeding, so that the machining efficiency of difficult-to-machine materials such as titanium alloy and high-temperature alloy is improved. The end, connected with the circumferential edge, of the bottom edge is used for increasing the maximum cutting depth after cutting, and the front angle corresponding to the bottom edge is gradually increased in the radial direction, away from the central axis of the cutting part, of the cutting part, so that the end, close to the circumferential edge, of the bottom edge is sharper, cutting resistance is reduced, cutting force and cutting heat are reduced, and the wear resistance of the cutter is improved; and the service life of the cutter is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of cutting tool technology, and in particular to an end mill. Background Technology

[0002] Currently, common end mills typically use a circular arc with radius R as the bottom cutting edge. The bottom cutting edge is smoothly connected to a connecting edge and a circumferential cutting edge, with the radius r of the connecting edge being smaller than the radius R of the bottom cutting edge. Using a bottom cutting edge with radius R results in a smaller principal cutting edge angle. When roughing difficult-to-machine materials such as high-temperature alloys and titanium alloys, the difficulty is high due to factors such as cutting heat and material deformation. When using the aforementioned end mill to machine parts made of these materials, the smaller principal cutting edge angle of the bottom cutting edge allows for thinner chips, increasing feed rate and achieving a higher material removal rate.

[0003] However, when the depth of cut ap is greater than the tangent point between the bottom cutting edge with radius R and the connecting cutting edge with radius r, the principal cutting edge angle Kr at the connecting cutting edge increases sharply compared to the bottom cutting edge angle Kr because R is greater than r. This results in a significant increase in chip thickness, making the connecting cutting edge prone to wear or chipping. This is especially true when machining difficult-to-machine materials such as high-temperature alloys and titanium alloys, where the wear of the connecting cutting edge is more pronounced and the probability of chipping is greater. Furthermore, considering that the closer the cutting point is to the circumferential cutting edge, the higher the linear velocity, and the greater the cutting force and cutting heat, this will undoubtedly exacerbate the wear of the connecting cutting edge, accelerating tool wear and failure.

[0004] Therefore, such tools are generally limited to a maximum depth of cut not exceeding the tangent point between the bottom edge and the connecting edge, which undoubtedly limits the cutting depth of the tool and the improvement of the material removal rate of the workpiece. Utility Model Content

[0005] The purpose of this invention is to provide an end mill that can increase the maximum depth of cut while reducing the cutting thickness, thereby extending the service life of the end mill.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] An end mill includes a cutting section having a plurality of cutting edges arranged circumferentially around its own central axis. The cutting edges include a circumferential cutting edge disposed on the outer periphery of the cutting section and a bottom cutting edge disposed at one end of the cutting section, with one end of the bottom cutting edge tangentially connected to one end of the circumferential cutting edge.

[0008] The bottom cutting edge is distributed on a plane of revolution formed by rotating a quarter ellipse around the central axis of the cutting part. The major axis of the bottom cutting edge is perpendicular to the axis of the cutting part, and the minor axis of the bottom cutting edge is parallel to or coincides with the axis of the cutting part. Along the radial direction of the cutting part away from its own central axis, the rake angle corresponding to the bottom cutting edge gradually increases.

[0009] As one possible implementation of the above-mentioned end mill, half of the major axis length of the bottom cutting edge is a, and half of the minor axis length of the bottom cutting edge is b, where 0.05≤b / a≤0.2.

[0010] As one possible implementation of the above-mentioned end mill, half of the major axis length of the bottom cutting edge is a, and the outer diameter of the cutting part is Dc, where 0.4≤a / Dc≤0.6;

[0011] And / or, the distance between the central axis of the cutting part and the short axis of the bottom blade is d, where d ≤ 0.1 mm.

[0012] As one possible implementation of the above-mentioned end mill, the bottom cutting edge includes a first bottom cutting edge and a second bottom cutting edge. The end of the cutting part is provided with a bottom rake face and a first bottom cutting edge relief face. The bottom rake face and the first bottom cutting edge relief face intersect to form the first bottom cutting edge. The cutting part is provided with a circumferential rake face. The circumferential rake face and the first bottom cutting edge relief face intersect to form the second bottom cutting edge.

[0013] The angle between the bottom rake face connected to the first bottom cutting edge and the base surface of the end mill is the rake angle γ2, 0°<γ2≤10°; and / or, the rake angle between the bottom rake face connected to the second bottom cutting edge and the base surface of the end mill is γ3, γ2>γ3, 10°≤γ3≤30°;

[0014] The base plane corresponding to any point on the cutting edge is a plane that passes through that point and is perpendicular to the feed direction of the end mill.

[0015] As one possible implementation of the above-mentioned end mill, the projection length of the second bottom cutting edge on the preset plane is L1, L1 = a - a × cosθ, where a is half the length of the major axis of the bottom cutting edge, and the preset plane is perpendicular to the central axis of the cutting part, 0° < θ ≤ 30°.

[0016] As one possible implementation of the above-mentioned end mill, the included angle between the first bottom cutting edge relief face and the cutting plane of the end mill is a relief angle α2, where 5°≤α2≤15°;

[0017] And / or, the side of the first bottom back face away from the first bottom edge is connected to a second bottom edge back face, and the angle between the second bottom edge back face and the cutting plane is a back angle α3, α2<α3, 10°≤α3≤30°.

[0018] As one possible implementation of the above-mentioned end mill, the cutting part is further provided with a circumferential rake face, and the circumferential rake face and the circumferential rake face intersect to form the circumferential cutting edge;

[0019] The angle between the circumferential flank face that is in contact with the circumferential flank face and the cutting plane is the flank angle α1, where 5°≤α1≤15°;

[0020] And / or, the included angle between the circumferential rake face and the base surface that are in contact with the circumferential cutting edge is the rake angle γ1, where 0° < γ1 ≤ 10°.

[0021] As one possible implementation of the above-mentioned end mill, each of the bottom cutting edges is provided with at least one bottom chip breaker groove, and the bottom chip breaker grooves of all the bottom cutting edges are arranged at radial intervals along the cutting portion;

[0022] And / or, each of the circumferential cutting edges is provided with at least one circumferential chip breaker groove, and the circumferential chip breaker grooves on all the circumferential cutting edges are arranged at radial intervals along the cutting portion.

[0023] As one possible implementation of the above-mentioned end mill, the width of the bottom chip breaker groove is W, 0.1mm≤W≤0.6mm;

[0024] And / or, the distance between two adjacent bottom chip breaker grooves along the radial direction of the cutting portion is L2, 0.05mm≤L2≤0.2mm;

[0025] And / or, the depth of the bottom chip breaker groove is h, where h is greater than the maximum chip thickness corresponding to the feed per tooth at the bottom chip breaker groove, 0.05mm≤h≤0.3mm.

[0026] As one possible implementation of the above-mentioned end mill, the number of bottom cutting edges is even, and the plurality of bottom cutting edges includes at least one pair of long bottom cutting edges and at least one pair of short bottom cutting edges. A long bottom cutting edge is arranged between two adjacent short bottom cutting edges, and a short bottom cutting edge is arranged between two adjacent long bottom cutting edges. Each pair of long bottom cutting edges is arranged 180° rotationally symmetrically around the circumference of the cutting part and is fixedly connected in the central region of the end of the cutting part. Each pair of short bottom cutting edges is arranged 180° rotationally symmetrically around the circumference of the cutting part. Each pair of short bottom cutting edges is arranged at intervals on opposite sides of a pair of long bottom cutting edges, or each pair of short bottom cutting edges is fixedly connected in the central region of the end of the cutting part.

[0027] Alternatively, the number of bottom cutting edges is odd, and multiple bottom cutting edges are arranged at intervals in the central region of the end of the cutting part.

[0028] The beneficial effects of this utility model are as follows: By setting the bottom cutting edge to be distributed on the rotating surface formed by rotating a 1 / 4 ellipse around the central axis of the cutting part, the principal cutting edge angle increases gradually and smoothly from the center of the end mill to the outer periphery of the end mill. This allows the end of the bottom cutting edge connected to the circumferential cutting edge to also be used for cutting, which is beneficial to increasing the depth of cut. Under the same depth of cut, the chips become thinner and longer, which is beneficial to achieving a better thin-cutting effect during rapid feed, thereby improving the machining efficiency of difficult-to-machine materials such as titanium alloys and high-temperature alloys.

[0029] The end of the bottom edge connected to the circumferential edge increases the maximum cutting depth after cutting. By setting a radial angle along the cutting part away from its own central axis, the rake angle of the bottom edge gradually increases, making the end of the bottom edge closer to the circumferential edge sharper, reducing cutting resistance, cutting force and cutting heat, and improving the wear resistance of the tool. Attached Figure Description

[0030] Figure 1 This is a side view of the end mill provided in this embodiment of the utility model;

[0031] Figure 2 This is a schematic diagram of the end face of the end mill provided in this embodiment of the utility model, viewed from the side where the bottom cutting edge is located towards the side where the clamping part is located;

[0032] Figure 3 This is a diagram showing the positional relationship between the bottom cutting edge, the bottom rake face, and the circumferential rake face provided in this embodiment of the utility model.

[0033] Figure 4 yes Figure 1 A magnified view of a portion of point C in the middle;

[0034] Figure 5 yes Figure 4 Sectional view along line A2-A2;

[0035] Figure 6 yes Figure 4 Sectional view along line A3-A3;

[0036] Figure 7 yes Figure 4 Sectional view along line A1-A1;

[0037] Figure 8 This is a schematic diagram of the end mill provided in this embodiment of the utility model;

[0038] Figure 9 This is a partial schematic diagram of the end mill provided in an embodiment of the present utility model;

[0039] Figure 10 This is a schematic diagram showing all the bottom chip-breaking grooves of the cutting part provided in this embodiment of the utility model rotated onto the same cutting edge.

[0040] In the picture:

[0041] 1. Cutting section; 11. Circumferential cutting edge; 12. Bottom cutting edge; 121. First bottom cutting edge; 122. Second bottom cutting edge; 13. Circumferential rake face; 14. Circumferential flank face; 15. Circumferential chip breaker groove; 16. Bottom rake face; 17. First bottom flank face; 18. Second bottom flank face; 19. Bottom chip breaker groove;

[0042] 2. Clamping part. Detailed Implementation

[0043] 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 present 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, not the entire structure.

[0044] In the description of this utility model, 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 utility model based on the specific circumstances.

[0045] 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.

[0046] 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 this utility model. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0047] like Figures 1 to 3As shown, an embodiment of this utility model provides an end mill, the end mill cutting part 1, the cutting part 1 has a plurality of cutting edges arranged circumferentially around its own central axis, the cutting edges include a circumferential cutting edge 11 disposed on the outer periphery of the cutting part 1, and a bottom cutting edge 12 disposed at one end of the cutting part 1, one end of the bottom cutting edge 12 being tangentially connected to one end of the circumferential cutting edge 11; the bottom cutting edge 12 is distributed on a rotational surface formed by rotating a 1 / 4 ellipse around the central axis of the cutting part 1, the major axis of the bottom cutting edge 12 is perpendicular to the axis of the cutting part 1, and the minor axis of the bottom cutting edge 12 is parallel to or coincides with the axis of the cutting part 1; along the radial direction of the cutting part 1 away from its own central axis, the rake angle corresponding to the bottom cutting edge 12 gradually increases.

[0048] Specifically, the parametric equations of the ellipse are x = a × cosθ, y = b × sinθ, where a is half the length of the major axis, b is half the length of the minor axis, and θ is the angle between the line connecting a point on the ellipse and the center of the ellipse and the major axis, ranging from 0° to 90°. The slope of a point on the bottom edge is k = (y / x)' = (b × sinθ / a × cosθ)' = b × cosθ / a × (﹣sinθ) = ﹣b × cosθ / a × sinθ = tanKr. The principal angle of the bottom edge is Kr = arctan(﹣b × cosθ / a × sinθ). With a and b constant, the smaller θ is, the larger Kr is, and Kr changes relatively smoothly with θ.

[0049] According to the formula for the principal cutting edge angle Kr, it can be seen that the principal cutting edge angle increases gradually and smoothly from the center of the end mill to the outer periphery of the end mill. This allows the end of the bottom cutting edge 12 connected to the circumferential cutting edge 11 to also be used for cutting, which is beneficial to increase the depth of cut. Under the same depth of cut, the chips become thinner and longer, which is beneficial to achieve a better thin cutting effect during rapid feed, thereby improving the machining efficiency of difficult-to-machine materials such as titanium alloys and high-temperature alloys.

[0050] The end of the bottom cutting edge 12 connected to the circumferential cutting edge 11 is used to increase the maximum cutting depth after cutting, which will increase the cutting resistance and cutting heat. By setting the radial direction away from its own central axis along the cutting part 1, the rake angle corresponding to the bottom cutting edge 12 gradually increases, making the end of the bottom cutting edge 12 closer to the circumferential cutting edge 11 sharper, reducing cutting resistance, reducing cutting force and cutting heat, improving the wear resistance of the tool, and extending the tool's service life.

[0051] This end mill can increase the maximum depth of cut and extend the service life of the end mill while reducing the cutting thickness to ensure a thin cutting effect.

[0052] For example, there are four circumferential cutting edges 11 and four bottom cutting edges 12, with the bottom cutting edges 12 and the circumferential cutting edges 11 connected one-to-one. It should be noted that the circumferential cutting edges 11 can also be provided with two, three, five, six or more, etc., which will not be listed here.

[0053] According to the formula for the principal cutting edge angle of the bottom cutting edge, a larger a and a smaller b are more conducive to reducing the principal cutting edge angle and the cutting thickness. However, a small b will limit the cutting depth during face milling. Conversely, a smaller a and a larger b, while increasing b is beneficial to increasing the cutting depth during face milling, will result in a larger principal cutting edge angle Kr at the bottom cutting edge, which is less conducive to reducing the chip thickness. Therefore, in some embodiments, 0.05 ≤ b / a ≤ 0.2. When b / a is greater than 0.2, b will be too large, resulting in an excessively large principal cutting edge angle at the end of the bottom cutting edge 12 near the circumferential cutting edge 11, leading to an excessively large cutting thickness. When b / a is less than 0.05, b will be too small, resulting in an excessively small maximum cutting depth during face milling. By limiting 0.05 ≤ b / a ≤ 0.2, a larger cutting depth can be achieved while maintaining a smaller cutting thickness.

[0054] In some embodiments, such as Figure 1 and Figure 3 As shown, the outer diameter of the cutting part 1 is Dc, and 0.4 ≤ a / Dc ≤ 0.6. If a / Dc is greater than 0.6, the length of the bottom cutting edge 12 will be too long, which is not conducive to the circumferential spacing of multiple bottom cutting edges 12 along the cutting part 1; if a / Dc < 0.4, the length of the bottom cutting edge 12 used to reduce cutting will be reduced, which is not conducive to increasing the cutting depth. By limiting 0.4 ≤ a / Dc ≤ 0.6, the cutting depth can be guaranteed while taking into account the arrangement of multiple bottom cutting edges 12.

[0055] For example, 0.4 ≤ a / Dc < 0.5, in other words, the bottom cutting edge 12 and its central axis are located on the same side of the central axis of the cutting part 1, and the central axes of the plurality of bottom cutting edges 12 are arranged circumferentially around the central axis of the cutting part 1. In other embodiments, a / Dc = 0.5 can also be used, in which case the distance between the central axis of the cutting part 1 and the major axis of the bottom cutting edge 12 is equal to zero, and the central axis of the bottom cutting edge coincides with the central axis of the cutting part 1. Alternatively, 0.5 < a / Dc ≤ 0.6 can be used, in which the bottom cutting edge 12 and its central axis are located on opposite sides of the central axis of the cutting part 1, and the central axes of the plurality of bottom cutting edges 12 are arranged circumferentially around the central axis of the cutting part 1.

[0056] In some embodiments, such as Figures 1 to 3 As shown, the distance between the central axis of the cutting section 1 and the minor axis of the bottom cutting edge 12 is d, where d ≤ 0.1 mm. This arrangement helps to ensure the depth of cut while accommodating multiple tool arrangements. It should be noted that... Figure 3 , Figure 9 and Figure 10 In the diagram, J1 represents the central axis of the cutting part 1, and J2 represents the direction of the minor axis of the ellipse parallel to the central axis of J1.

[0057] In some embodiments, such as Figure 2 and Figure 3 As shown, the bottom cutting edge 12 includes a first bottom cutting edge 121 and a second bottom cutting edge 122. The end of the cutting part 1 is provided with a bottom rake face 16 and a first bottom flank face 17. The bottom rake face 16 and the first bottom flank face 17 intersect to form the first bottom cutting edge 121. The outer periphery of the cutting part 1 is provided with a circumferential rake face 13. The circumferential rake face 13 and the first bottom flank face 17 intersect to form the second bottom cutting edge 122. Figure 3 In the diagram, the first bottom cutting edge 121 refers to curve EF, and the second bottom cutting edge 122 refers to curve FG. Point E refers to the endpoint of the bottom cutting edge 12 away from the circumferential cutting edge 11, point F refers to the intersection of the circumferential cutting edge, the bottom cutting edge 12, and the bottom front cutting edge 16, and point G refers to the tangent point of the circumferential cutting edge 11 and the bottom cutting edge 12.

[0058] The projection length of the second bottom cutting edge 122 on the preset plane is L1, L1 = a - a × cosθ, where a is half the length of the major axis of the bottom cutting edge 12. The preset plane is perpendicular to the central axis of the cutting part 1, and 0° < θ ≤ 30°.

[0059] like Figures 4 to 6 As shown, the angle between the bottom rake face 16 connected to the first bottom cutting edge 121 and the base surface of the end mill is the rake angle γ2, where 0° < γ2 ≤ 10°; the rake angle between the bottom rake face 16 connected to the second bottom cutting edge 122 and the base surface of the end mill is γ3, where γ2 > γ3, and 10° ≤ γ3 ≤ 30°. The base surface corresponding to any point on the cutting edge is a plane passing through that point and perpendicular to the feed direction of the end mill.

[0060] The smaller θ is, the larger the principal cutting edge angle Kr of the bottom cutting edge 12 is, resulting in a larger cutting thickness and a gradually increasing cutting depth. As the cutting depth gradually increases, the chip thickness generated by the second bottom cutting edge 122 during cutting is greater than that generated by the first bottom cutting edge 121. The closer the point on the bottom cutting edge 12 is to the circumferential cutting edge 11, the greater the linear velocity, and the greater the cutting force and cutting heat generated. Therefore, the rake angle γ3 corresponding to the second bottom cutting edge 122 is greater than the rake angle γ2 corresponding to the first bottom cutting edge 121, making the second bottom cutting edge 122 sharper. This reduces the cutting force and cutting heat generated by the second bottom cutting edge 122, thereby reducing cutting resistance and increasing the service life of the end mill.

[0061] In some embodiments, such as Figure 5 and Figure 6 As shown, the angle between the first bottom back face 17 and the base surface is the back angle α2, 5°≤α2≤15°; the side of the first bottom back face 17 away from the first bottom cutting edge 121 is connected to the second bottom back face 18, and the angle between the second bottom back face 18 and the base surface is the back angle α3, α2<α3, 10°≤α3≤30°.

[0062] To meet chip removal requirements, a second bottom rake face 18 is added, and α2 is limited to α3, which can reduce chip removal resistance and improve the service life of the end mill.

[0063] In some embodiments, such as Figure 1 and Figure 7 As shown, the cutting part 1 is also provided with a circumferential flank face 14. The circumferential rake face 13 and the circumferential flank face 14 intersect to form a circumferential cutting edge 11. The angle between the circumferential flank face 14, which is in contact with the circumferential flank face 14, and the base surface of the end mill is the clearance angle α1, where 5°≤α1≤15°. The angle between the circumferential rake face 13, which is in contact with the circumferential cutting edge 11, and the base surface of the end mill is the rake angle γ1, where 0°<γ1≤10°. By limiting the rake angle γ1 and the clearance angle α1, the cutting capability of the circumferential cutting edge 11 meets the cutting requirements. It should be noted that the circumferential flank face 14 is not limited to one. Two or more circumferential flank faces 14 can be provided according to the chip removal requirements. This is a common technique in the art and will not be described in detail here.

[0064] In some embodiments, such as Figures 8 to 10 As shown, each bottom cutting edge 12 is provided with at least one bottom chip breaker groove 19, and the bottom chip breaker grooves 19 of all bottom cutting edges 12 are arranged at radial intervals along the cutting part 1.

[0065] The so-called bottom chip breaker grooves 19 of all bottom cutting edges 12 are arranged radially at intervals along the cutting part 1. This means that when any bottom cutting edge 12 is rotated around the central axis of the cutting part 1, the bottom chip breaker grooves 19 of the bottom cutting edge 12 do not coincide with the bottom chip breaker grooves 19 on other bottom cutting edges 12. This allows the chips generated by the bottom cutting edge 12 to be cut into multiple segments by multiple bottom chip breaker grooves 19, reducing the length of the chip after chip breaking, reducing the amount of chip deformation, reducing cutting heat and cutting force, which is beneficial to increasing the depth of cut and extending the tool life.

[0066] In some embodiments, such as Figure 9 As shown, the width of the bottom chip breaking groove 19 is W, 0.1mm≤W≤0.6mm.

[0067] The greater the depth of the chip breaker groove, the greater the depth of chip breaking, and the greater the cutting depth. However, due to the grinding process, the width W of the chip breaker groove is also greater, which is less favorable to the overall structural strength of the end mill. Therefore, limiting W to 0.1mm≤W≤0.6mm can meet the structural strength requirements of the end mill while taking into account the cutting depth requirements.

[0068] In some embodiments, such as Figure 10As shown, the distance between two adjacent bottom chip breaker grooves 19 along the radial direction of the cutting section 1 is L2, 0.05mm≤L2≤0.2mm. This ensures that the length of each chip after being broken by the bottom chip breaker groove 19 is between 0.05mm and 0.2mm, which is not too large, thus improving chip removal smoothness.

[0069] In some embodiments, such as Figure 9 As shown, the depth of the bottom chip breaker groove 19 is h, where 0.05mm ≤ h ≤ 0.3mm. Specifically, h is usually greater than the maximum chip thickness corresponding to the feed per tooth at the bottom chip breaker groove 19. This setting ensures that the depth h of the bottom chip breaker groove 19 meets the chip requirements, and the chip thickness will not exceed the depth of the bottom chip breaker groove 19.

[0070] In some embodiments, such as Figure 8 As shown, each circumferential cutting edge 11 is provided with at least one circumferential chip breaker groove 15, and the circumferential chip breaker grooves 15 on all circumferential cutting edges 11 are arranged at radial intervals along the cutting portion 1. Exemplarily, each circumferential cutting edge 11 is provided with one circumferential chip breaker groove 15.

[0071] The so-called arrangement of the circumferential chip breaker grooves 15 of all circumferential cutting edges 11 at radial intervals along the cutting part 1 means that when any circumferential cutting edge 11 is rotated around the central axis of the cutting part 1, the circumferential chip breaker grooves 15 on the circumferential cutting edge 11 do not coincide with the circumferential chip breaker grooves 15 on other circumferential cutting edges 11. This allows the chips generated by the cutting of the circumferential cutting edge 11 to be cut into multiple segments by multiple circumferential chip breaker grooves 15, reducing the length of the chip after chip breaking, reducing the amount of chip deformation, reducing cutting heat and cutting force, which is beneficial to increasing the depth of cut and extending the tool life.

[0072] In some embodiments, such as Figure 8 As shown, the number of bottom cutting edges 12 is even, and each pair of bottom cutting edges 12 includes at least one pair of long bottom cutting edges and at least one pair of short bottom cutting edges. A long bottom cutting edge is arranged between two adjacent short bottom cutting edges, and a short bottom cutting edge is arranged between two adjacent long bottom cutting edges. Each pair of long bottom cutting edges is arranged 180° rotationally symmetrically around the circumference of the cutting part 1 and is fixedly connected to the central region of the end of the cutting part 1. Each pair of short bottom cutting edges is arranged 180° rotationally symmetrically around the circumference of the cutting part 1 and is spaced apart on opposite sides of a pair of long bottom cutting edges. Alternatively, each pair of short bottom cutting edges can be fixedly connected to the central region of the end of the cutting part 1.

[0073] This configuration allows a pair of bottom long cutting edges to connect through the central area of ​​the cutting section 1. During the cutting process, the bottom long cutting edges can cut at the bottom center of the cutting section 1 and enhance chip removal. This effectively avoids the serious chip blockage problem of the bottom cutting edge 12 during the high-efficiency machining process of the end mill with rapid feed, and also improves the strength of the root of the bottom cutting edge 12 of the end mill, avoiding the problem of the center of the root of the bottom cutting edge 12 of the end mill chipping.

[0074] It should be noted that the number of circumferential cutting edges 11 is not limited to four; it can also be two, four, six, or eight, etc. The more circumferential cutting edges 11 and bottom cutting edges 12 there are, the higher the wear resistance of the end mill, but the smaller the chip clearance space between adjacent edges, which is less conducive to chip removal. For example, the cutting part 1 has four circumferential cutting edges 11 and bottom cutting edges 12 connected to each of the four circumferential cutting edges 11. This ensures smooth chip removal while maintaining the wear resistance of the end mill.

[0075] In other embodiments, the number of bottom cutting edges 12 can also be an odd number, such as 3, 5, or 7, etc. Multiple bottom cutting edges 12 are arranged at intervals in the central area of ​​the end of the cutting part 1 to improve cutting uniformity.

[0076] In some embodiments, such as Figure 1 As shown, the end mill also includes a clamping part 2, which is connected to the end of the cutting part 1 away from the bottom cutting edge 12. The clamping part 2 is a cylindrical structure, which is convenient for clamping with a fixture during subsequent use.

[0077] For example, the end mill is a one-piece structure.

[0078] Obviously, the above embodiments of this utility model are merely examples for clearly illustrating the present utility model, and are not intended to limit the implementation of the present utility model. Those skilled in the art can make various obvious changes, readjustments, and substitutions without departing from the protection scope of this utility model. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the protection scope of the claims of this utility model.

Claims

1. An end mill characterized by, The cutting part (1) has a plurality of cutting edges arranged circumferentially around the central axis of the cutting part (1), and the cutting edges include a circumferential edge (11) arranged at the outer periphery of the cutting part (1) and a bottom edge (12) arranged at one end of the cutting part (1), one end of the bottom edge (12) being tangentially connected to one end of the circumferential edge (11). The bottom edge (12) is distributed on a rotary surface formed by rotating a 1 / 4 ellipse around the central axis of the cutting part (1), the long axis of the bottom edge (12) is perpendicular to the axis of the cutting part (1), and the short axis of the bottom edge (12) is parallel to or coincides with the axis of the cutting part (1); along the radial direction of the cutting part (1) away from the central axis thereof, the rake angle of the corresponding bottom edge (12) gradually increases.

2. The end mill according to claim 1, characterized in that Half of the length of the long axis of the bottom edge (12) is a, half of the length of the short axis of the bottom edge (12) is b, and 0.05≤b / a≤0.

2.

3. The end mill according to claim 1, wherein Half of the length of the long axis of the bottom edge (12) is a, the outer diameter of the cutting part (1) is Dc, and 0.4≤a / Dc≤0.

6. And / or, the distance between the central axis of the cutting part (1) and the short axis of the bottom edge (12) is d, and d≤0.1mm.

4. The end mill of claim 1, wherein, The bottom edge (12) includes a first bottom edge (121) and a second bottom edge (122), the end of the cutting part (1) is provided with a bottom rake surface (16) and a first bottom relief surface (17), the bottom rake surface (16) and the first bottom relief surface (17) intersect to form the first bottom edge (121); the cutting part (1) is provided with a circumferential rake surface (13), the circumferential rake surface (13) and the first bottom relief surface (17) intersect to form the second bottom edge (122); The included angle between the bottom rake surface (16) connected to the first bottom edge (121) and the base surface of the end mill is a rake angle γ2, and 0°<γ2≤10°; and / or, the included angle between the bottom rake surface (16) connected to the second bottom edge (122) and the base surface of the end mill is a rake angle γ3, γ2>γ3, and 10°≤γ3≤30°; The base surface corresponding to any point on the cutting edge is a plane passing through the point and perpendicular to the feed direction of the end mill.

5. The end mill according to claim 4, wherein The projection length of the second bottom edge (122) on a preset plane is L1, L1=a-a×cosθ, a is half of the length of the long axis of the bottom edge (12), the preset plane is perpendicular to the central axis of the cutting part (1), and 0°<θ≤30°.

6. The end mill according to claim 4, wherein The included angle between the first bottom relief surface (17) and the cutting plane of the end mill is a relief angle α2, and 5°≤α2≤15°; And / or, the first bottom relief surface (17) is connected to a second bottom relief surface (18) on the side away from the first bottom edge (121), the included angle between the second bottom relief surface (18) and the cutting plane is a relief angle α3, α2<α3, and 10°≤α3≤30°.

7. The end mill according to claim 6, wherein The cutting part (1) is also provided with a peripheral clearance face (14), the peripheral clearance face (13) and the peripheral clearance face (14) intersect to form the peripheral edge (11); An included angle between the peripheral clearance face (14) and the cutting plane intersecting with the peripheral clearance face (14) is a clearance angle α1, 5°≤α1≤15°; And / or, an included angle between the peripheral edge (11) and the base face intersecting with the peripheral edge (11) is a rake angle γ1, 0°<γ1≤10°.

8. The end mill according to any one of claims 1 to 7, characterized in that Each of the bottom edges (12) is provided with at least one bottom chip breaker groove (19), and the bottom chip breaker grooves (19) of all the bottom edges (12) are arranged in a radial direction of the cutting part (1) and are spaced apart; And / or, each of the peripheral edges (11) is provided with at least one peripheral chip breaker groove (15), and the peripheral chip breaker grooves (15) of all the peripheral edges (11) are arranged in a radial direction of the cutting part (1) and are spaced apart.

9. The end mill according to claim 8, wherein A groove width of the bottom chip breaker groove (19) is W, 0.1mm≤W≤0.6mm; And / or, a spacing between two adjacent bottom chip breaker grooves (19) in the radial direction of the cutting part (1) is L2, 0.05mm≤L2≤0.2mm; And / or, a depth of the bottom chip breaker groove (19) is h, h is greater than a maximum chip thickness corresponding to a feed per tooth at the bottom chip breaker groove (19), 0.05mm≤h≤0.3mm.

10. The end mill according to any one of claims 1 to 7, characterized in that The number of the bottom edges (12) is even, a plurality of the bottom edges (12) includes at least one pair of bottom long edges and at least one pair of bottom short edges, one bottom long edge is arranged between two adjacent bottom short edges, and one bottom short edge is arranged between two adjacent bottom long edges; each pair of the bottom long edges is arranged in 180° rotational symmetry around the circumference of the cutting part (1) and is fixedly connected in a central area at an end of the cutting part (1), and each pair of the bottom short edges is arranged in 180° rotational symmetry around the circumference of the cutting part (1); each pair of the bottom short edges is arranged on opposite sides of a pair of the bottom long edges in a spaced manner, or each pair of the bottom short edges is fixedly connected in the central area at the end of the cutting part (1); Or, the number of the bottom edges (12) is odd, and a plurality of the bottom edges (12) are arranged in a spaced manner in the central area at the end of the cutting part (1).

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