A milling insert and a milling cutter

Abstract

The present invention discloses a milling blade, which includes a blade body. The blade body includes an upper surface, a lower surface, and a plurality of side surfaces connecting the upper surface and the lower surface. The upper surface and the side surfaces form a cutting edge, and the cutting edge includes a main cutting edge, a circular arc tip edge, and a secondary cutting edge connected in sequence. A rake face of the main cutting edge is provided inside the main cutting edge, a rake face of the circular arc edge is provided inside the circular arc tip edge, and a rake face of the secondary cutting edge is provided inside the secondary cutting edge. The main cutting edge, the circular arc tip edge, and the secondary cutting edge are connected in sequence. The rake angle of the rake face of the main cutting edge gradually increases in a direction away from the rake face of the circular arc edge. The rake face of the circular arc edge is a concave-convex curved surface, and the rake angle of the rake face of the secondary cutting edge is constant. A milling cutter is also disclosed. The milling blade and the milling cutter have the advantages of improving the chip shape, avoiding the chip from scratching the surfaces of the blade and the workpiece, prolonging the service life of the blade, and improving the machining quality of the workpiece surface, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of cutting blades, and particularly to a milling blade and a milling cutter. Background Art

[0002] Currently, for mainstream indexable double-sided cutting blades, in order to improve the overall sharpness of the tool and due to the structural limitations of double-sided edge blades, rake angle compensation is usually performed on the blade to achieve a double positive angle cutting edge with a positive axial rake angle and a positive radial rake angle, thereby reducing the cutting force during cutting and improving the service life of the blade to a certain extent. However, there are certain problems with the double positive angle cutting edge of existing blades in chip control. In milling operations, under the combined action of its own weight and centrifugal force, the chip has a tendency to tilt outward when the blade starts to cut into the workpiece, forming a disc-shaped spiral chip (as shown in Figure 15 ). Under the cutting conditions of large cutting width, the chip is relatively long, and the disordered outward movement of the chip is likely to scratch the unused cutting edge and easily bite into the gap between the tool and the machined surface, damaging the machined surface and the tool while causing a sudden change in the cutting force, compromising the quality and accuracy of the machined surface and reducing the blade life. Therefore, it is necessary to optimize and control the disordered movement state of the chip during milling. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a milling blade and a milling cutter that can improve the chip shape, avoid the chip from scratching the blade and the workpiece surface, extend the service life of the blade, and improve the machining quality of the workpiece surface.

[0004] To solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A milling blade includes a blade body. The blade body includes an upper surface, a lower surface, and a plurality of side surfaces connecting the upper surface and the lower surface. The upper surface and the side surfaces form a cutting edge. The cutting edge includes a main cutting edge, a circular arc tip edge, and a secondary cutting edge connected in sequence. A main cutting edge rake face is provided inside the main cutting edge. An arc edge rake face is provided inside the circular arc tip edge. A secondary cutting edge rake face is provided inside the secondary cutting edge. The main cutting edge, the circular arc tip edge, and the secondary cutting edge are connected in sequence. The rake angle of the main cutting edge rake face gradually increases in a direction away from the arc edge rake face. The arc edge rake face is a concave-convex curved surface. The rake angle of the secondary cutting edge rake face is constant.

[0006] As a further improvement of the above technical solution:

[0007] The arc edge rake face includes a connected concave surface and a convex surface. The concave surface is connected to the main cutting edge rake face. The convex surface is connected to the secondary cutting edge rake face.

[0008] The maximum height difference between the concave surface and the convex surface is 0 to 0.2 mm.

[0009] The cross-section of the concave surface relative to the deepest part is low in the middle and high around, and the cross-section of the convex surface relative to the highest part is high in the middle and low around.

[0010] The connecting line between the rake face of the circular arc cutting edge and the rake face of the main cutting edge is set as the first boundary line, and the connecting line between the rake face of the circular arc cutting edge and the rake face of the secondary cutting edge is set as the second boundary line. The angles between the first boundary line and the second boundary line and the flank face of the main cutting edge are both in the range of 20° to 60°.

[0011] The end point where the circular arc tip edge is connected to the main cutting edge is set as the first end point, and the end point where the circular arc tip edge is connected to the secondary cutting edge is set as the second end point. The distance between the first end point and the first boundary line is set as S1, and the distance between the second end point and the second boundary line is set as S2. Both S1 and S2 are in the range of -0.5 mm to +0.5 mm.

[0012] The concave surface accounts for 30% to 50% of the rake face of the circular arc cutting edge, and the convex surface accounts for 50% to 70% of the rake face of the circular arc cutting edge.

[0013] The curve formed by the concave surface in its cross-section is set as the C1 curve. The cross-section of the concave surface is perpendicular to the upper surface and is located between the first boundary line and the second boundary line. The cross-section where the C1 curve with the maximum depression amount is located is set as the first reference cross-section, and the angle between the first reference cross-section and the flank face of the main cutting edge is 20° to 60°.

[0014] The curve formed by the convex surface in its cross-section is set as the C2 curve. The cross-section of the convex surface is perpendicular to the upper surface and is located between the first boundary line and the second boundary line. The cross-section where the C2 curve with the maximum protrusion amount is located is set as the second reference cross-section, and the angle between the second reference cross-section and the flank face of the main cutting edge is 10° to 40°.

[0015] The rake face of the main cutting edge includes a rapid rake angle increasing surface and a slow rake angle increasing surface. The rapid rake angle increasing surface connects the rake face of the circular arc cutting edge and the slow rake angle increasing surface, and the rake angle increasing speed of the rapid rake angle increasing surface is greater than that of the slow rake angle increasing surface.

[0016] The rake angle increment of the rapid rake angle increasing surface is 5° to 20°, and the rake angle increment of the slow rake angle increasing surface is 0° to 5°.

[0017] The rapid rake angle increasing surface accounts for 20% to 50% of the rake face of the main cutting edge, and the slow rake angle increasing surface accounts for 50% to 80% of the rake face of the main cutting edge.

[0018] The rake face of the secondary cutting edge is lower than the convex surface.

[0019] A milling cutter includes a cutter body having a rotation axis. A plurality of mounting portions are provided on the circumferential side of the front end of the cutter body. The above-mentioned milling blades are mounted on the mounting portions through fasteners. The lower surface of the blade body contacts the mounting portion. The main cutting edge is located outside the circumferential side of the cutter body, and the secondary cutting edge is located outside the end side of the cutter body. The rake face of the main cutting edge, the rake face of the arc edge, and the rake face of the secondary cutting edge face the rotation direction of the cutter body.

[0020] As a further improvement of the above technical solution:

[0021] The mounting portion is in a groove shape.

[0022] A chip fluting groove connected to the mounting portion is provided on the cutter body.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] For the milling blade of the present invention, the rake face of the main cutting edge with a gradually changing rake angle, the concave-convex rake face of the arc edge, and the rake face of the secondary cutting edge with a constant rake angle are adopted to effectively control the shape and flow direction of the chip during the milling process, so that the chip shape rises in a spiral manner along the direction of the main cutting edge with a relatively uniform curling radius, and can maintain a stable spiral trend as the chip becomes longer, improving the disc-shaped spiral shape and flow direction in which the curling radius of the conventional double positive rake edge type rapidly increases and tilts outward. Thereby, it avoids the chip scratching the unused edge angle of the blade, avoids the chip disorderly tilting and scratching the surface of the workpiece, and avoids the chip biting into the gap between the machined workpiece and the blade, resulting in an abnormal increase in the cutting force, thereby prolonging the service life of the blade and improving the machining quality of the workpiece surface.

[0025] A milling cutter of the present invention includes a milling blade and has all the advantages of the milling blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a perspective structural schematic diagram of the milling blade of the present invention.

[0027] Figure 2 is a top view structural schematic diagram of the milling blade of the present invention.

[0028] Figure 3 is Figure 2 the magnification at the arc tip edge in Figure 1 .

[0029] Figure 4 is Figure 2 the sectional view of E-E in

[0030] Figure 5 is Figure 2 the sectional view of F-F in

[0031] Figure 6 is Figure 2 the sectional view of G-G in it.

[0032] Figure 7 is Figure 2 the sectional view of H-H in it, where H-H is the section of the front rake face of the longitudinal auxiliary cutting edge and the convex surface 5212.

[0033] Figure 8 is Figure 2 the enlarged view at the arc tip edge in it Figure 2 .

[0034] Figure 9 is Figure 8 the sectional view of V-V in it, where V-V is the section of the transverse concave surface, C1 is the curve formed by the concave surface in the section, designated as the C1 curve, that is, the V-V plane is the section that makes the C1 curve have the maximum depression amount T1; R1 is the radius of curvature of the C1 curve.

[0035] Figure 10 is Figure 8 the sectional view of U-U in it, where U-U is the section of the transverse convex surface, C2 is the curve formed by the convex surface in the section, designated as the C2 curve, that is, the U-U plane is the section that makes the C2 curve have the maximum protrusion amount T2;; R2 is the radius of curvature of the C2 curve.

[0036] Figure 11 is the schematic three-dimensional structure diagram of the milling cutter of the present invention.

[0037] Figure 12 is the schematic side view structure diagram of the milling cutter of the present invention.

[0038] Figure 13 is the schematic bottom view structure diagram of the milling cutter of the present invention.

[0039] Figure 14 The state diagram of chip formation of the milling insert of the invention.

[0040] Figure 15 The state diagram of chip formation of the existing double-sided cutting insert.

[0041] Each label in the figure represents:

[0042] 1. Blade body; 105. Installation part; 106. Chip groove; 109. Axis of rotation; 11. First boundary line; 110. Cutter body; 12. Second boundary line; 2. Upper surface; 200. Fastener; 3. Lower surface; 4. Side surface; 41. Major flank; 5. Cutting edge; 51. Major cutting edge; 511. Major cutting edge rake face; 5111. Rapidly increasing rake face; 5112. Slowly increasing rake face; 52. Round nose cutting edge; 5201. First end point; 5202. Second end point; 521. Round edge rake face; 5211. Concave surface; 5212. Convex surface; 53. Minor cutting edge; 531. Minor cutting edge rake face; 5201. First end point; 5202. Second end point. Detailed implementation mode

[0043] The present invention will be further described in detail below in conjunction with the accompanying drawings of the specification and specific embodiments.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0045] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0046] In the present invention, unless otherwise clearly specified and defined, the terms "assembled", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] Example 1:

[0048] Figures 1 to 10An embodiment of the milling blade of the present invention is shown. The milling blade of this embodiment includes a blade body 1. The blade body 1 includes an upper surface 2, a lower surface 3, and a plurality of side surfaces 4 connecting the upper surface 2 and the lower surface 3. The upper surface 2 and the side surfaces 4 form a cutting edge 5. The cutting edge 5 includes a main cutting edge 51, an arc tip edge 52, and a secondary cutting edge 53 connected in sequence. A main cutting edge rake face 511 is provided inside the main cutting edge 51, an arc edge rake face 521 is provided inside the arc tip edge 52, and a secondary cutting edge rake face 531 is provided inside the secondary cutting edge 53. The main cutting edge 51, the arc tip edge 52, and the secondary cutting edge 53 are connected in sequence. The rake angle of the main cutting edge rake face 511 gradually increases in the direction away from the arc edge rake face 521. The arc edge rake face 521 is a concave-convex curved surface, and the rake angle of the secondary cutting edge rake face 531 is constant.

[0049] This milling blade adopts a main cutting edge rake face 511 with a gradually changing rake angle, a concave-convex arc edge rake face 521, and a secondary cutting edge rake face 531 with a constant rake angle to effectively control the shape and flow direction of the chip during the milling process, so that the chip shape rises spirally along the direction of the main cutting edge with a relatively uniform curling radius (as shown in Figure 14 ), and can maintain a stable spiral trend as the chip becomes longer (as shown in Figure 14 ), improving the disc-shaped spiral shape and flow direction with a rapidly increasing curling radius and tilting outward of the conventional double positive rake edge type, thereby avoiding the chip scratching the unused cutting edge angle of the blade, avoiding the chip disorderly pouring and scratching the surface of the workpiece, and avoiding the chip biting into the gap between the machined workpiece and the blade resulting in an abnormal increase in the cutting force, thereby prolonging the service life of the blade and improving the machining quality of the workpiece surface.

[0050] Inside the main cutting edge 51 (on the side facing the upper surface 2), there is a main cutting edge rake face 511 with a gradually changing rake angle, which can make the chip increase the tendency to flow inward when contacting the main cutting edge rake face 511 and curling upward to resist the tendency to tilt outward due to centrifugal force. Inside the arc tip edge 52 (on the side facing the upper surface 2), there is a concave-convex arc edge rake face 521. The concavity and convexity can control the size of the curling radius at the bottom of the chip, offset the tendency of it to gradually become larger, thereby controlling the shape of the chip, forming a uniform spiral chip, and preventing the chip from tilting outward. Inside the secondary cutting edge 53 (on the side facing the upper surface 2), there is a secondary cutting edge rake face 531 with a constant rake angle to maintain the stability of the cutting force and ensure the finishing effect of the secondary cutting edge. The rake faces of the above-mentioned parts are connected to each other.

[0051] Furthermore, as shown in Figure 1 , Figure 2 , Figure 9 and Figure 10As shown in the figure, in this embodiment, the arc-edge rake face 521 includes a concave surface 5211 and a convex surface 5212 that are connected. The concave surface 5211 is connected to the main cutting-edge rake face 511, and the convex surface 5212 is connected to the secondary cutting-edge rake face 531. The maximum height difference between the concave surface 5211 and the convex surface 5212 is 0 to 0.2 mm. The concave surface 5211 and the convex surface 5212 form different rake angles. When the chip flows through, different frictional forces are generated on different parts of the chip. The convex surface 5212 is the root of the chip and is the position where the maximum frictional force is generated, which can effectively control the problem that the chip curl radius gradually increases during the cutting of the blade, and at the same time resist the influence of the centrifugal force causing the blade to tilt outward. The setting range of this embodiment is the result of finite element simulation calculation and actual cutting experiment verification, which can balance the relationship between the chip control function and the cutting force generated by the friction between the chip and the rake face and the cutting edge strength. If the maximum height difference between the concave surface 5211 and the convex surface 5212 exceeds the range of 0 to 0.2 mm, it will lead to an unreasonable chip curl radius, an excessive increase in the cutting force caused by excessive friction, or insufficient strength of the blade cutting edge, etc.

[0052] The arc-edge rake face 521 of the arc tip edge is a concave-convex curved surface. The concave surface 5211 is formed by concavity on the side close to the main cutting-edge rake face 511, and the convex surface 5212 is formed by convexity on the side close to the secondary cutting-edge rake face 531. The maximum height difference between the concave surface 5211 and the convex surface 5212 is between 0 and 0.2 mm, that is, 0 < T1 + T2 < 0.2, where T1 is the maximum depression amount of the concave surface 5211 and T2 is the maximum protrusion amount of the convex surface 5212. Figure 9 For Figure 8 the sectional view of V-V in the figure, the concave surface 5211 has a concave structure. V-V is the section cutting across the concave surface, C1 is the curve formed by the concave surface in the section, and T1 is the depression amount of C1 relative to the connecting line of both ends. Figure 10 For Figure 8 the sectional view of U-U in the figure, the convex surface 5212 has a convex shape. Among them, U-U is the section cutting across the convex surface, C2 is the curve formed by the convex surface in the section, and T2 is the protrusion amount of C2 relative to the connecting line of both ends.

[0053] Furthermore, as Figure 2 shown in the figure, in this embodiment, the connecting line between the arc-edge rake face 521 and the main cutting-edge rake face 511 is set as the first boundary line 11, and the connecting line between the arc-edge rake face 521 and the secondary cutting-edge rake face 531 is set as the second boundary line 12. The included angles between the first boundary line 11 and the second boundary line 12 and the main flank face 41 of the main cutting edge 51 are both within the range of 20° to 60°.

[0054] In this embodiment, from Figure 2During the observation, the range of the front tool face 521 of the arc cutting edge tip is within but not limited to the extension range of the arc cutting edge tip 52. The front tool face 521 of the arc cutting edge tip extends from the arc cutting edge tip 52 towards the upper surface 2. As Figure 3 shown, the included angle between the first boundary line 11 and the flank face 41 of the main cutting edge 51 is α1, and the included angle between the second boundary line 12 and the flank face 41 of the main cutting edge 51 is α2. α1 and α2 are within the range of 20° to 60°.

[0055] Furthermore, as Figure 3 shown, in this embodiment, the endpoint where the arc cutting edge tip 52 is connected to the main cutting edge 51 is set as the first endpoint 5201, and the endpoint where the arc cutting edge tip 52 is connected to the secondary cutting edge 53 is set as the second endpoint 5202. The distance between the first endpoint 5201 and the first boundary line 11 is set as S1, and the distance between the second endpoint 5202 and the second boundary line 12 is set as S2. Both S1 and S2 are within the range of -0.5 mm to +0.5 mm. The included angles and positions of the first boundary line 11 and the second boundary line 12 with respect to the flank face 41 of the main cutting edge 51 determine the range of the arc cutting edge front tool face 521. The concave-convex shape inside it is the key position for chip control. An overly large range of the arc cutting edge front tool face 521 will cause the internal concave-convex structure to extend too much and reduce the chip control ability. An overly small arc cutting edge front tool face 521 will cause the internal concave-convex structure to be too compact, which is also not conducive to chip control. At the same time, it will increase the friction between the chip and the arc cutting edge front tool face 521, which is not beneficial to the tool life. In addition, blades with the same external dimensions may have different sizes of arc cutting edge tips 52 due to different usage requirements. For different sizes of arc cutting edge tips 52, it is necessary to maintain basically the same concave-convex structure of the arc cutting edge front tool face 521. The range set in this embodiment can adapt to various arc cutting edge tips 52 from R0.2 to R2.0.

[0056] Furthermore, the curve of the concave surface 5211 on the cross-section (such as the V-V plane) is lower in the middle and higher at both ends relative to the tangent plane of the most concave part of the curve. The curve of the convex surface 5212 on the cross-section (such as the U-U plane) is higher in the middle and lower at both ends relative to the tangent plane of the most convex part of the curve. Further, the curve of the concave surface 5211 on the longitudinal section perpendicular to the V-V plane is lower in the middle and higher at both ends relative to the tangent plane of the most concave part of the curve. The curve of the convex surface 5212 on the longitudinal section perpendicular to the U-U plane is higher in the middle and lower at both ends relative to the tangent plane of the most convex part of the curve. That is to say, the concave surface 5211 is lower in the middle and higher around relative to the tangent plane of the most concave part, and the convex surface 5212 is higher in the middle and lower around relative to the tangent plane of the most convex part.

[0057] Furthermore, in this embodiment, the concave surface 5211 accounts for 30% to 50% of the arc cutting edge front tool face 521, and the convex surface 5212 accounts for 50% to 70% of the arc cutting edge front tool face 521.

[0058] The concave surface 5211 is bounded by the first boundary line 11, and the concave surface 5211 occupies 30% - 50% of the arc-edge rake face 521. The concave surface 5211 is connected to the rake face 511 of the major cutting edge with an increasing rake angle. While reducing the cutting force, it jointly forms the control of the upper end of the chip. The overall proportion of the concave surface 5211 on the arc-edge rake face 521 is slightly smaller than that of the convex surface 5212. When the proportion range of the concave surface 5211 is less than 30% - 50%, after the chip is formed, it flows inward along the rake face and will contact the convex surface 5212 before forming a spiral curl, resulting in too small a chip curl radius and a tendency to tilt outward, which is not conducive to chip control. When the proportion of the concave surface 5211 exceeds 30% - 50%, the chip flows too much toward the inner side of the blade, resulting in too large a curl radius at the bottom of the chip. Under the action of centrifugal force and gravity, it will tilt outward and present a disc-shaped chip structure, which is likely to scratch the flank face of the blade.

[0059] The convex surface 5212 is bounded by the second boundary line 12, and its range is between 50% and 70% of the arc-edge rake face 521. The main function of the convex surface 5212 is to control the curl radius at the bottom of the chip. In this embodiment, the proportion range of the convex surface 5212 is the optimal range. Too small a proportion will weaken the control of the bottom radius of the chip, resulting in a larger chip curl radius, thereby increasing the action of centrifugal force and gravity on the chip. The chip presents a disc-shaped structure and tilts outward. Too large a proportion will result in too small a chip curl radius, increasing the cutting force and the chip length being too long, resulting in uncontrollable chips.

[0060] Further, as Figure 8 and Figure 9 shown, in this embodiment, the curve formed by the concave surface 5211 in its cross-section is set as the C1 curve. The cross-section of the concave surface 5211 is perpendicular to the upper surface 2 and is located between the first boundary line 11 and the second boundary line 12. The cross-section where the C1 curve with the maximum depression amount is located is set as the first reference cross-section (V-V plane), and the angle between the first reference cross-section and the major flank face 41 is 20° - 60°.

[0061] Further, as Figure 8 and Figure 10 shown, in this embodiment, the curve formed by the convex surface 5212 in its cross-section is set as the C2 curve. The cross-section of the convex surface 5212 is perpendicular to the upper surface 2 and is located between the first boundary line 11 and the second boundary line 12. The cross-section where the C2 curve with the maximum protrusion amount is located is set as the second reference cross-section (U-U plane), and the angle between the second reference cross-section and the major flank face 41 is 10° - 40°.

[0062] As Figure 8As shown, the angle of the first reference cross-section (plane V-V) relative to the main flank 41 is set as θ1, and the angle of the second reference cross-section (plane U-U) relative to the main flank 41 is set as θ2. θ1 ranges from 20° to 60°, and θ2 ranges from 10° to 40°. The concave surface 5211 extends inwards at the angles set by θ1 and θ2 in this embodiment, which coincides with the generation and flow direction of the required chips. If it is too small, the space in the chip outflow direction will be reduced; if it is too large, the control of the chips will be weakened. Beyond the set range of this embodiment, the chip control ability will be reduced.

[0063] θ2 is slightly smaller than θ1, which determines the length of contact with the bottom of the chip. If the angles of θ1 and θ2 are too large, the length of contact with the chip will be reduced; if the contact is too small, the control of the chip will be weakened, which is not conducive to the chip forming a spiral curl. If the angle is too small, the length of contact with the bottom of the chip will increase, and the excessive contact range will lead to an increase in the friction between the chip and the rake face, an increase in the cutting force, and an adverse effect on the tool life. The set range of this embodiment is the optimal range.

[0064] Furthermore, as Figure 1 and Figure 2 shown, in this embodiment, the main cutting edge rake face 511 includes a rapid rake angle increasing face 5111 and a slow rake angle increasing face 5112. The rapid rake angle increasing face 5111 connects the circular arc edge rake face 521 and the slow rake angle increasing face 5112, and the rake angle increase rate of the rapid rake angle increasing face 5111 is larger than that of the slow rake angle increasing face 5112.

[0065] The range of the main cutting edge rake face 511 is from the starting point 5101 of the main cutting edge 51 to between the first boundary line 11. The rake angle β gradually increases from the first boundary line 11 of the circular arc edge rake face 521 towards the starting point 5101. As Figure 4 、 Figure 5 and Figure 6 shown, the E-E, F-F, and G-G planes are different planes perpendicular to the main cutting edge 51 and the upper surface 2, and are arranged in sequence along the main cutting edge 51 from the end point 5121 (the starting point of the circular arc tip edge 52) towards the starting point 5101. Both the E-E and F-F planes intersect with the rapid rake angle increasing face 5111, and the G-G plane intersects with the slow rake angle increasing face 5112. The rake angle of the rapid rake angle increasing face 5111 on the E-E plane is set as β1 (as Figure 4 shown), the rake angle of the rapid rake angle increasing face 5111 on the F-F plane is set as β2 (as Figure 5 shown), and the rake angle of the slow rake angle increasing face 5112 on the G-G plane is set as β3 (as Figure 6As shown in the figure, it can be seen from the cross-sectional view that β1 < β2 < β3. The rake face 511 of the main cutting edge with a gradually increasing rake angle β is beneficial to reducing the cutting force, and at the same time can control the chip flow direction. The chip curls upward along the rake face 511 of the main cutting edge. Under the influence of centrifugal force and its own weight, it will flow outwards. The gradually increasing rake angle β can make the friction force between the upper part of the chip and the rake face 511 of the main cutting edge less than that between the lower part and the rake face 511 of the main cutting edge. At the same time, through the control of the chip by the circular arc tool tip edge 52 at the bottom of the chip, a flow trend of the chip towards the inside is generated to resist the influence of centrifugal force and its own weight.

[0066] Furthermore, in this embodiment, the rake angle increment of the rapidly increasing rake angle surface 5111 is 5° - 20°, and the rake angle increment of the slowly increasing rake angle surface 5112 is 0° - 5°.

[0067] The rapidly increasing rake angle surface 5111 extends along the main cutting edge 51 towards the starting point 5101, which is the rapidly increasing region of the rake angle β. The slowly increasing rake angle surface 5112 extends along the main cutting edge 51 towards the starting point 5101, which is the slowly increasing region of the rake angle β. It can be clearly seen from Figure 4 、 Figure 5 、 Figure 6 that β2 - β1 > β3 - β2, and the rake angle increasing speeds in the two regions are different. The rapidly increasing rake angle surface 5111 is connected to the circular arc tool tip edge 52 and is a commonly used surface from the perspective of cutting depth. The slowly increasing rake angle surface 5112 is an infrequently used surface. At the same time, when the slowly increasing rake angle surface 5112 is used, the cutting width is usually relatively small, the chip is short, and the requirement for chip control is not high. Therefore, different parts of the rake face 511 of the main cutting edge need to be controlled separately. The rapidly increasing rake angle surface 5111 is the key control region, and its rake angle β increases relatively fast, which is more beneficial for chip control. And the slowly increasing rake angle surface 5112 only needs to have a certain degree of rake angle change.

[0068] Furthermore, in this embodiment, the rapidly increasing rake angle surface 5111 accounts for 20% - 50% of the rake face 511 of the main cutting edge, and the slowly increasing rake angle surface 5112 accounts for 50% - 80% of the rake face 511 of the main cutting edge. In cutting, when the cutting width is large, the chip is long, and the requirement for chip control is high. For the purpose of reducing the cutting load, a smaller cutting depth will be adopted when the cutting width is large. Therefore, the proportion of the rapidly increasing rake angle surface 5111 is smaller than that of the slowly increasing rake angle surface 5112. Specifically, as Figure 2 shown, the length of the rapidly increasing rake angle surface 5111 along the main cutting edge 51 is H1, the length of the slowly increasing rake angle surface 5112 along the main cutting edge 51 is H2, and the total length of the rake face 511 of the main cutting edge along the main cutting edge 51 is H1 + H2. H1 / (H1 + H2) = 20% - 50%, and H2 / (H1 + H2) = 50% - 80%.

[0069] Furthermore, in this embodiment, the rake face 531 of the secondary cutting edge is lower than the convex surface 5212. The range of the rake face 531 of the secondary cutting edge is between the second boundary line 12 of the arc cutting edge rake face 521 and the end point 5301 of the secondary cutting edge 53. The rake angle formed by the rake face 531 of the secondary cutting edge remains constant. When the chip is generated and flows, it will come into contact with the rake face 531 of the secondary cutting edge. However, due to the control of the chip by the arc cutting edge rake face 521, the chip will not penetrate deeply into the rake face 531 of the secondary cutting edge. Therefore, the constant rake face 531 of the secondary cutting edge can meet the requirements of chip control.

[0070] In the view observed from the vertical direction of the rake face 531 of the secondary cutting edge, as Figure 6 shown, the height of the rake face 531 of the secondary cutting edge is lower than the convex surface 5212 as a whole. If the rake face 531 of the secondary cutting edge is higher than the convex surface 5212, it will cause the friction between the chip and the secondary cutting edge 53 to increase. At the same time, the higher rake face 531 of the secondary cutting edge will cause the rake angle of the secondary cutting edge 53 to become smaller, which will lead to an increase in the cutting force and thus affect the finishing effect of the secondary cutting edge 53.

[0071] Furthermore, the blade body 1 is made of a hard material such as cemented carbide but not limited to cemented carbide, forming a polygonal plate shape and having a centrosymmetric structure.

[0072] Embodiment 2:

[0073] Figures 11 to 13 An embodiment of the milling cutter of the present invention is shown. The milling cutter of this embodiment includes a cutter body 110 having a rotation axis 109. A plurality of mounting portions 105 are provided on the peripheral side of the front end of the cutter body 110. The milling blades of the embodiment are mounted on the mounting portions 105 through fasteners 200. The lower surface 3 of the blade body 1 is in contact with the mounting portion 105. The main cutting edge 51 is located outside the peripheral side of the cutter body 110, and the secondary cutting edge 53 is located outside the end side of the cutter body 110. The main cutting edge rake face 511, the arc cutting edge rake face 521, and the secondary cutting edge rake face 531 face the rotation direction of the cutter body 110.

[0074] During use, the cutter body 110 rotates around the rotation axis 109. The body 1 of the cutting blade is mounted on the mounting portion 105 through the fastener 200. Specifically, the fastener 200 passes through the mounting hole in the middle of the blade body 1 and presses the blade body 1. This milling cutter includes all the technical features of the milling blade and has all the advantages of the milling blade.

[0075] The tool body 110 can rotate about the rotation axis 109 in the rotation direction R. The tool body 110 has a front end face 102 and a rear end face 103. The outer peripheral envelope surface 104 of the tool body 110 extends between the front end face 102 and the rear end face 103. The tool body 110 is connected to a tool holder (not shown) via the rear end face 103 and is installed on a machine tool. A plurality of mounting portions 105 for mounting milling cutters are formed between the front end face 102 and the outer peripheral envelope surface 104. A chip discharging functional chip groove 106 is provided in the upper part of the mounting portion 105. The lower surface 3 of the cutter blade body 1 contacts the mounting portion 105, and the side surface 4 of the cutter blade body 1 contacts the contact surface of the inner side surface of the mounting portion 105, and is fixed by a fastener 200 (such as a screw). A chip groove 106 connected to the mounting portion 105 is provided on the tool body 110.

[0076] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the above-disclosed technical content, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A milling insert, comprising a insert body (1), the insert body (1) comprising an upper surface (2), a lower surface (3), and a plurality of side surfaces (4) connecting the upper surface (2) and the lower surface (3), the upper surface (2) and the side surfaces (4) forming a cutting edge (5), the cutting edge (5) comprising a main cutting edge (51), a circular arc tip edge (52), and a secondary cutting edge (53) connected in sequence, the main cutting edge (51) having a main cutting edge rake face (511) on its inner side, the circular arc tip edge (52) having a circular arc tip edge face (521) on its inner side, the secondary cutting edge (53) having a secondary cutting edge rake face (531) on its inner side, the main cutting edge (51), the circular arc tip edge (52), and the secondary cutting edge (53) being connected in sequence, characterized in that: The rake angle of the main cutting edge rake face (511) gradually increases in a direction away from the arc edge rake face (521); the arc edge rake face (521) is a concave-convex curved surface; the rake angle of the secondary cutting edge rake face (531) is constant; the arc edge rake face (521) comprises a connected lower concave surface (5211) and an upper convex surface (5212); the lower concave surface (5211) is connected to the main cutting edge rake face (511); and the upper convex surface (5212) is connected to the secondary cutting edge rake face (531).

2. The milling insert according to claim 1, characterized in that: The maximum height difference between the lower concave surface (5211) and the upper convex surface (5212) is 0-0.2 mm.

3. The milling insert according to claim 2, characterized in that: The lower concave surface (5211) is lower in the middle and higher around the periphery relative to the cross-section of the most concave part, and the upper convex surface (5212) is higher in the middle and lower around the periphery relative to the cross-section of the most convex part.

4. The milling insert according to claim 2, characterized in that: A line connecting the circular arc edge rake face (521) and the main cutting edge rake face (511) is set as a first boundary line (11), a line connecting the circular arc edge rake face (521) and the secondary cutting edge rake face (531) is set as a second boundary line (12), and angles between the first boundary line (11) and the second boundary line (12) and the main flank face (41) of the main cutting edge (51) are both within a range of 20° to 60°.

5. The milling insert according to claim 4, characterized in that: The endpoint where the circular arc cutting edge (52) connects with the main cutting edge (51) is set as the first endpoint (5201), the endpoint where the circular arc cutting edge (52) connects with the secondary cutting edge (53) is set as the second endpoint (5202), the distance between the first endpoint (5201) and the first boundary line (11) is set as S1, and the distance between the second endpoint (5202) and the second boundary line (12) is set as S2, and both S1 and S2 are within the range of -0.5 mm to +0.5 mm.

6. The milling insert according to claim 4, characterized in that: The lower concave surface (5211) accounts for 30% to 50% of the circular arc edge rake surface (521), and the upper convex surface (5212) accounts for 50% to 70% of the circular arc edge rake surface (521).

7. The milling insert according to claim 4, characterized in that: The curve formed by the concave surface (5211) on its cross-section is set as the C1 curve. The cross-section of the concave surface (5211) is perpendicular to the upper surface (2) and is located between the first boundary line (11) and the second boundary line (12). The cross-section where the C1 curve with the maximum concave amount is located is set as a first reference cross-section. The angle between the first reference cross-section and the main back tool surface (41) is 20°~60°.

8. The milling insert according to claim 4, characterized in that: The curve formed by the upper convex surface (5212) on its cross-section is set as the C2 curve. The cross-section of the upper convex surface (5212) is perpendicular to the upper surface (2) and is located between the first boundary line (11) and the second boundary line (12). The cross-section where the C2 curve with the maximum protrusion is located is set as the second reference cross-section. The angle between the second reference cross-section and the main back tool surface (41) is 10°~40°.

9. The milling insert according to any one of claims 1 to 8, characterized in that: The main cutting edge rake face (511) comprises a rake angle rapid increasing surface (5111) and a rake angle slow increasing surface (5112); the rake angle rapid increasing surface (5111) connects the arc edge rake face (521) and the rake angle slow increasing surface (5112); the rake angle increasing rate of the rake angle rapid increasing surface (5111) is greater than that of the rake angle slow increasing surface (5112).

10. The milling insert according to claim 9, characterized in that: The rake angle increment of the rake angle fast increasing surface (5111) is 5°~20°, and the rake angle increment of the rake angle slow increasing surface (5112) is 0°~5°.

11. The milling insert according to claim 9, characterized in that: The fast-increasing rake angle surface (5111) accounts for 20% to 50% of the rake face (511) of the main cutting edge, and the slow-increasing rake angle surface (5112) accounts for 50% to 80% of the rake face (511) of the main cutting edge.

12. The milling insert according to claim 3, characterized in that: The secondary cutting edge rake surface (531) is lower than the upper convex surface (5212).

13. A milling tool, comprising a tool body (110) having a rotation axis (109), wherein a plurality of mounting portions (105) are provided around the front end of the tool body (110), wherein: A milling blade according to any one of claims 1 to 12 is mounted on the mounting portion (105) via a fastener (200); a lower surface (3) of the blade body (1) contacts the mounting portion (105); the main cutting edge (51) is located outside the peripheral side of the tool body (110); the secondary cutting edge (53) is located outside the end side of the tool body (110); and the main cutting edge rake face (511), the arc edge rake face (521) and the secondary cutting edge rake face (531) face the rotation direction of the tool body (110).

14. The milling tool according to claim 13, characterized in that: The mounting portion (105) is in a groove shape.

15. The milling tool according to claim 14, characterized in that: The cutter body (110) is provided with a chip groove (106) connected to the mounting portion (105).

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