Milling cutter

Abstract

The present invention discloses a milling cutter. The milling cutter includes a tool shank, the tool shank has an installation end and a connection end which are arranged back to back, and a plurality of first installation surfaces are arranged at intervals along the circumferential direction of the tool shank on the side wall of the installation end; the milling cutter further includes a plurality of first blades, each of the first blades is installed on one of the first installation surfaces, and each of the first blades has a cutting edge facing the rotation direction of the tool shank; the milling cutter further includes a plurality of second blades, the plurality of second blades are arranged at intervals around the central axis of the tool shank on the end surface of the installation end, and each of the second blades has a cutting surface facing the rotation direction of the tool shank. The technical solution of the present invention aims to solve the problem of the single function of the traditional milling cutter.

Description

Technical Field

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

[0002] A milling cutter is a rotating tool with one or more cutting teeth for milling operations. During operation, each cutting tooth intermittently removes the surplus material of the workpiece in turn. Milling cutters are mainly used for plane machining, step machining, and workpiece cutting on milling machines. Existing milling cutters can be divided into two types: side milling cutters and end milling cutters. Side milling cutters can only be used for side milling, and end milling cutters can only be used for end milling. During the milling process, when changing from side milling to end milling, the corresponding tool needs to be replaced, which is troublesome and time-consuming.

[0003] The above content is only used to assist in understanding the technical solution of the present application, and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The main object of the present invention is to propose a milling cutter, aiming to solve the problem of the single function of traditional milling cutters.

[0005] To achieve the above object, a milling cutter proposed by the present invention includes a tool shank. The tool shank has an installation end and a connection end arranged back to back. A plurality of first installation surfaces are provided at intervals along the circumferential direction of the tool shank on the side wall of the installation end.

[0006] The milling cutter further includes a plurality of first cutting blades. Each first cutting blade is installed on one of the first installation surfaces, and each first cutting blade has a cutting edge facing the rotation direction of the tool shank.

[0007] The milling cutter further includes a plurality of second cutting blades. The plurality of second cutting blades are arranged at intervals around the central axis of the tool shank on the end face of the installation end, and each second cutting blade has a cutting surface facing the rotation direction of the tool shank.

[0008] In an embodiment of the present invention, the cutting edge extends along the direction from the installation end to the connection end, and the extension direction of the cutting edge forms an angle with the axis of the tool shank.

[0009] In the rotation direction of the tool shank, one end of the cutting edge close to the end face of the installation end is arranged in front of the other end of the cutting edge far from the end face of the installation end.

[0010] In an embodiment of the present invention, the first blade includes a first side wall, a second side wall, a third side wall, a fourth side wall, a fifth side wall, a sixth side wall, and a seventh side wall that are sequentially arranged and connected along its circumferential direction. The first side wall abuts against the first mounting surface and is arranged opposite to the fifth side wall. The back-facing direction of the second side wall forms an obtuse angle with the back-facing direction of the first side wall. The third side wall is arranged as a concave curved surface. The back-facing direction of the fourth side wall forms an obtuse angle with the back-facing direction of the fifth side wall. The fourth side wall and the fifth side wall enclose the cutting edge. The distance between the sixth side wall and the first side wall gradually increases along the rotation direction of the tool shank. The seventh side wall is arranged opposite to the fourth side wall.

[0011] In an embodiment of the present invention, the first blade is provided with a chip breaker groove, which is formed by enclosing the second side wall, the third side wall, and the fourth side wall. The notch of the chip breaker groove is arranged towards the rotation direction of the tool shank.

[0012] In an embodiment of the present invention, define the included angle between the fourth side wall and the plane where the first side wall 210 is located as α, then α satisfies the condition 45° < α < 90°.

[0013] In an embodiment of the present invention, a cutting portion is convexly provided on the end face of the first blade near the mounting end, and the cutting portion and the first blade are an integrally formed structure.

[0014] In an embodiment of the present invention, the cutting portion includes a top surface facing away from the tool shank, and the height of the top surface gradually increases along the rotation direction of the first blade;

[0015] And / or, the cutting portion includes a top surface facing away from the tool shank, and the height of the top surface gradually decreases from the center of the tool shank towards the outside.

[0016] In an embodiment of the present invention, the second blade includes a cutting surface, a second side wall, a third side wall, a fourth side wall, a fifth side wall, and a sixth side wall that are sequentially arranged and connected along its circumferential direction. The cutting surface is arranged opposite to the fifth side wall. The second side wall is arranged opposite to the sixth side wall. The third side wall and the fourth side wall form an obtuse angle. The back-facing direction of the fourth side wall forms an acute angle with the back-facing direction of the fifth side wall;

[0017] The second blade further includes a second mounting surface facing the mounting end and a top wall facing the mounting end in the direction of the facing surface. The second mounting surface abuts against the end face of the mounting end, and the top wall is arranged opposite to the second mounting surface.

[0018] In an embodiment of the present invention, the height of the top wall gradually increases along the rotation direction of the milling cutter.

[0019] In an embodiment of the present invention, a chip removal surface is further provided between two adjacent first mounting surfaces. The chip removal surface is sunken relative to the outer sidewall of the tool shank, and the sinking depth of the chip removal surface gradually increases from the mounting end to the connecting end.

[0020] The technical solution of the present invention provides a milling cutter. The milling cutter includes a tool shank with a mounting end and a connecting end arranged opposite to each other. The sidewall of the mounting end is provided with a plurality of first mounting surfaces spaced along the circumferential direction of the tool shank; the milling cutter further includes a plurality of first cutting blades, each first cutting blade is mounted on a first mounting surface, and each first cutting blade has a cutting edge facing the rotation direction of the tool shank; the milling cutter further includes a plurality of second cutting blades, and the plurality of second cutting blades are spaced around the central axis of the tool shank on the end face of the mounting end, and each second cutting blade has a cutting surface facing the rotation direction of the tool shank. The connecting end is connected to an external rotating device to drive the entire milling cutter to rotate, so as to achieve the purpose of rotary cutting of the milling cutter; the sidewall of the mounting end is provided with a plurality of first mounting surfaces spaced along the circumferential direction of the tool shank, and the first cutting blades are mounted on the first mounting surfaces, making the installation of the first cutting blades simpler and more convenient; the first cutting blades are provided with cutting edges, so that the first cutting blades can be used for side cutting. The design that the cutting edges protrude from the first mounting surfaces makes it easier for the cutting edges to contact the workpiece, improving the processing efficiency. The second cutting blades are mounted on the end face of the mounting end, and the second cutting blades have cutting surfaces, so that the second cutting blades can be used for end face cutting; thus, the milling cutter has the functions of side cutting and end face cutting, and it is not necessary to replace the tool when changing from side cutting to end face cutting, achieving the effect of expanding the cutting function of the milling cutter, so that the milling cutter can be used for end face cutting and side cutting. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0022] Figure 1 It is a schematic structural diagram of an embodiment of a milling cutter of the present invention;

[0023] Figure 2 It is a schematic structural diagram of an embodiment of the tool shank;

[0024] Figure 3 For Figure 2 The partial enlarged view at A in

[0025] Figure 4 It is a schematic structural diagram of an embodiment of the first cutting blade;

[0026] Figure 5 is Figure 4 an isometric view of;

[0027] Figure 6 is a schematic structural view of an embodiment of a second blade;

[0028] Figure 7 is Figure 6 a right view of.

[0029] Explanation of reference numerals in the drawings:

[0030] Label Name Label Name 100 Tool shank 200 First blade 300 Second blade 110 Mounting end 120 Connection end 130 First mounting surface 140 Chip removal surface 210 First side wall 220 Second side wall 230 Third side wall 240 Fourth side wall 250 Fifth side wall 260 Sixth side wall 270 Seventh side wall 280 Cutting part 281 Top surface 400 Cutting edge 500 Chip breaker groove 310 Cutting surface 320 Top wall 330 Second mounting surface

[0031] The realization of the object of the present invention, functional features and advantages will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0034] In addition, if there are descriptions such as "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their 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 at least one such feature. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0035] The present invention provides a milling cutter.

[0036] In the embodiments of the present invention, as Figure 1 , Figure 2 , and Figure 6As shown in the figure, a milling cutter is provided. The milling cutter includes a tool shank 100, which has an installation end 110 and a connection end 120 arranged back to back. On the side wall of the installation end 110, there are several first installation surfaces 130 arranged at intervals along the circumferential direction of the tool shank 100; the milling cutter further includes several first cutting blades 200, each first cutting blade 200 is installed on a first installation surface 130, and each first cutting blade 200 has a cutting edge 400 facing the rotation direction of the tool shank 100; the milling cutter further includes several second cutting blades 300, and the several second cutting blades 300 are arranged at intervals around the central axis of the tool shank 100 on the end face of the installation end 110, and each second cutting blade 300 has a cutting surface 310 facing the rotation direction of the tool shank 100. This effectively solves the problem that traditional milling cutters can only be used for side milling or end milling, and have a single function.

[0037] In the actual application process, there are various installation methods for the first cutting blade 200 and the second cutting blade 300 on the tool shank 100, which can be fusion welding installation, pressure welding installation, and brazing installation. Considering the technical effects, brazing installation is preferably adopted. Brazing can make the surface of the welded joint smooth, have good airtightness, and the shape and size of the welded part are stable. The structure and performance of the welded part change little; in the actual application process, the first cutting blade 200 and the second cutting blade 300 are installed at the same end of the tool shank 100, and both are installed at the end of the tool shank 100 close to the installation end 110, so that the first cutting blade 200 and the second cutting blade 300 can work simultaneously, improving the working efficiency of the milling cutter.

[0038] The material of the tool shank 100 can be various, such as tungsten carbide cobalt-based cemented carbide, tungsten carbide titanium cobalt-based cemented carbide, tungsten carbide niobium-based cemented carbide, tungsten carbide-based cemented carbide, etc. Considering the economic cost and hardness factors, tungsten carbide-based cemented carbide is preferably adopted. Tungsten carbide-based cemented carbide has high hardness and is not easy to wear; the materials of the first cutting blade 200 and the second cutting blade 300 can also be various, such as cubic boron nitride, polycrystalline cubic boron nitride, and polycrystalline diamond. Considering the cutting effect, polycrystalline diamond is preferably adopted. Polycrystalline diamond has extremely high hardness and wear resistance, high thermal conductivity and low thermal expansion coefficient. During cutting, heat dissipation is fast, the cutting temperature is low, the thermal deformation is small, and the friction coefficient is small, which can reduce the surface roughness.

[0039] The technical solution of the present invention provides a milling cutter. The milling cutter includes a tool shank 100, which has an installation end 110 and a connection end 120 arranged back to back. Along the circumferential direction of the tool shank 100, several spaced first installation surfaces 130 are provided on the side wall of the installation end 110; the milling cutter further includes several first cutting blades 200, each first cutting blade 200 is installed on a first installation surface 130, and each first cutting blade 200 has a cutting edge 400 facing the rotation direction of the tool shank 100; the milling cutter also includes several second cutting blades 300, and the several second cutting blades 300 are arranged at intervals around the central axis of the tool shank 100 on the end face of the installation end 110, and each second cutting blade 300 has a cutting surface 310 facing the rotation direction of the tool shank 100. The connection end 120 is connected to an external rotating device to drive the entire milling cutter to rotate, so as to achieve the purpose of rotary cutting of the milling cutter; several spaced first installation surfaces 130 are provided along the circumferential direction of the tool shank 100 on the side wall of the installation end 110, and the first cutting blades 200 are installed on the first installation surfaces 130, making the installation of the first cutting blades 200 simpler and more convenient; the first cutting blades 200 are provided with cutting edges 400, so that the first cutting blades 200 can be used for side cutting. The design that the cutting edge 400 protrudes from the first installation surface 130 makes it easier for the cutting edge 400 to contact the workpiece, improving the processing efficiency. The second cutting blades 300 are installed on the end face of the installation end 110, and the second cutting blades 300 have cutting surfaces 310, so that the second cutting blades 300 can be used for end face cutting; thus, the milling cutter has the functions of side cutting and end face cutting, and it is not necessary to replace the tool when changing from side cutting to end face cutting, achieving the effect of expanding the cutting function of the milling cutter.

[0040] In an embodiment of the present invention, referring to Figure 1 and Figure 2 、 Figure 4 , the cutting edge 400 extends along the direction from the installation end 110 to the connection end 120, and the extension direction of the cutting edge 400 is set at an angle with the axis of the tool shank 100;

[0041] In the rotation direction of the tool shank 100, one end of the cutting edge 400 close to the end face of the installation end 110 is arranged in front of one end of the cutting edge 400 far from the end face of the installation end 110. The cutting edge 400 extends along the direction from the installation end 110 to the connection end 120, extending the cutting length of the cutting edge 400, making the cutting surface area of the cutting edge 400 larger, and improving the cutting efficiency; the extension direction of the cutting edge 400 is set at an angle with the axial direction of the tool shank 100, so that during the cutting process of the cutting edge 400, the contact area between the cutting edge 400 and the workpiece to be processed is reduced, thereby reducing the cutting force received by the cutting edge 400, making the cutting edge 400 not easily worn, and achieving the effect of extending the service life of the first cutting blade 200.

[0042] In an embodiment of the present invention, referring to Figure 4, the first blade 200 includes a first side wall 210, a second side wall 220, a third side wall 230, a fourth side wall 240, a fifth side wall 250, a sixth side wall 260, and a seventh side wall 270 that are sequentially arranged along its circumference and sequentially connected. The first side wall 210 abuts against the first mounting surface 130 and is disposed opposite to the fifth side wall 250. The back-facing direction of the second side wall 220 is set at an obtuse angle to the back-facing direction of the first side wall 210. The third side wall 230 is arranged as a concave curved surface. The back-facing direction of the fourth side wall 240 is set at an obtuse angle to the back-facing direction of the fifth side wall 250. The fourth side wall 240 and the fifth side wall 250 enclose a cutting edge 400. The distance between the sixth side wall 260 and the first side wall 210 gradually increases along the rotation direction of the tool handle 100. The seventh side wall 270 is disposed opposite to the fourth side wall 240. The first blade 200 includes the first side wall 210, the second side wall 220, the third side wall 230, the fourth side wall 240, the fifth side wall 250, the sixth side wall 260, and the seventh side wall 270 that are sequentially connected, thus forming the outer side wall of the first blade 200. The first side wall 210 abuts against the first mounting surface 130. In actual application, the first side wall 210 can abut against the first mounting surface 130 in various ways, which can be fusion welding, pressure welding, and brazing. Considering the technical effects, brazing is preferably used. Brazing can make the surface of the welded joint smooth, have good airtightness, and the shape and size of the welded part are stable. The third side wall 230 is arranged as a concave curved surface, which can control the chips generated by the cutting edge 400 inside the concave curved surface and prevent the generated chips from getting entangled. The back-facing direction of the fourth side wall 240 is set at an obtuse angle to the back-facing direction of the fifth side wall 250. The fourth side wall 240 and the fifth side wall 250 enclose the cutting edge 400. The cutting edge 400 is formed by the fourth side wall 240 and the fifth side wall 250 enclosing. Therefore, the included angle between the fourth side wall 240 and the fifth side wall 250 is an acute angle. The back-facing direction of the fourth side wall 240 is set at an obtuse angle to the back-facing direction of the fifth side wall 250, reducing the cutting force received by the cutting edge 400, making the cutting efficiency of the cutting edge 400 higher and the service life longer.

[0043] In an embodiment of the present invention, referring to Figure 4 and Figure 5 , the first blade 200 is provided with a chip-breaking groove 500. The chip-breaking groove 500 is formed by enclosing the second side wall 220, the third side wall 230, and the fourth side wall 240. The notch of the chip-breaking groove 500 is set towards the rotation direction of the tool handle 100. The chip-breaking groove 500 is formed by enclosing the second side wall 220, the third side wall 230, and the fourth side wall 240. Since the milling cutter rotates clockwise, the chips generated by the cutting edge 400 will be controlled within the chip-breaking groove 500 and then discharged outside the milling cutter through the chip-breaking groove 500, so that the chips do not get entangled, and the discharge direction of the chips is controlled, reducing the cutting resistance and extending the service life of the milling cutter.

[0044] In an embodiment of the present invention, with reference to Figure 4 and Figure 5 , define the included angle between the fourth side wall 240 and the plane where the first side wall 210 is located as α, then α satisfies the condition 45° < α < 90°. The included angle between the fourth side wall 240 and the plane where the first side wall 210 is located is the included angle between the fourth side wall 240 and the first mounting surface 130. The second side wall 220, the third side wall 230, and the fourth side wall 240 enclose a chip-breaking groove 500. Therefore, the included angle between the fourth side wall 240 and the first side wall 210 affects the angle of the groove wall of the chip-breaking groove 500. If α is too small, the chip-breaking effect of the chip-breaking groove 500 is poor and the broken chips cannot be discharged in time; if α is too large, it cannot prevent the chips from winding around the first blade 200, thereby increasing the cutting resistance. In order to achieve a proper cutting effect, α is limited to 45° - 90°.

[0045] In an embodiment of the present invention, with reference to Figure 4 and Figure 5 , a cutting portion 280 protrudes from the end surface of the first blade 200 close to the mounting end 110, and the cutting portion 280 and the first blade 200 are an integrally formed structure. A cutting portion 280 protrudes from the end surface of the first blade 200 close to the mounting end 110. The cutting portion 280 can be used for cutting the end surface of the milling cutter, increasing the cutting function of the milling cutter; the cutting portion 280 and the first blade 200 are an integrally formed structure, increasing the hardness of the cutting portion 280 and the first blade 200, making the first blade 200 not easily worn and extending the service life of the first blade 200.

[0046] In an embodiment of the present invention, with reference to Figure 4 and Figure 5 , the cutting portion 280 includes a top surface 281 facing away from the tool holder 100, and the height of the top surface 281 gradually increases along the rotation direction of the first blade 200; during the cutting process, the cutting portion 280 is in direct contact with the processed product. The height of the top surface 281 of the cutting portion 280 gradually increases along the rotation direction of the first blade 200, making the cutting of the cutting portion 280 more forceful and facilitating the dropping of the generated chips, avoiding the chips from sticking to the first blade 200 and affecting the cutting efficiency and cutting accuracy.

[0047] In an embodiment of the present invention, with reference to Figure 4 and Figure 5 , the cutting portion 280 includes a top surface 281 facing away from the tool holder 100, and the height of the top surface 281 gradually decreases from the center of the tool holder 100 outward. The top surface 281 is provided at one end of the tool holder 100 close to the mounting end 110, and the height of the top surface 281 gradually decreases from the center of the tool holder 100 outward, enabling the chips generated by the cutting portion 280 to be discharged outside the milling cutter along the top surface 281 in time, avoiding the chips from sticking to the cutting portion 280 and affecting the cutting efficiency and cutting effect of the cutting portion 280.

[0048] In an embodiment of the present invention, with reference to Figure 6 and Figure 7 , the second blade 300 includes a cutting surface 310, a second side wall 220, a third side wall 230, a fourth side wall 240, a fifth side wall 250, and a sixth side wall 260 that are sequentially arranged along its circumferential direction and sequentially connected. The cutting surface 310 and the fifth side wall 250 are arranged back to back, the second side wall 220 and the sixth side wall 260 are arranged back to back, the third side wall 230 and the fourth side wall 240 are arranged at an obtuse angle, and the back-facing direction of the fourth side wall 240 and the back-facing direction of the fifth side wall 250 are arranged at an acute angle;

[0049] The second blade 300 further includes a second mounting surface 330 facing the mounting end 110 and a top wall 320 facing the facing direction of the mounting end 110. The second mounting surface 330 abuts against the end surface of the mounting end 110, and the top wall 320 and the second mounting surface 330 are arranged back to back. The cutting surface 310 and the top wall 320 form a cutting edge 400 of the second blade 300, so that the second blade 300 can achieve the effect of being available for end face cutting; the second blade 300 abuts against the end surface of the mounting end 110 through the second mounting surface 330, so that the second blade 300 is mounted on the tool holder 100. The second mounting surface 330 and the end surface of the mounting end 110 can be abutted in various ways, which can be fusion welding, pressure welding, and brazing. Considering the technical effect, brazing is preferably used. Brazing can make the surface of the welded joint smooth, have good airtightness, and the shape and size of the welded part are stable;

[0050] In an embodiment of the present invention, with reference to Figure 6 and Figure 7 , the height of the top wall 320 gradually increases along the rotation direction of the milling cutter. The cutting generated by the cutting surface 310 will accumulate on the top wall 320. The height of the top wall 320 gradually increases along the rotation direction of the milling cutter, which can discharge the chips generated by the cutting surface 310 to the outside of the milling cutter in time. Moreover, the height of the top wall 320 gradually increases along the rotation direction of the milling cutter, reducing the contact area between the second blade 300 and the workpiece to be machined, thereby reducing the friction between the second blade 300 and the workpiece to be machined and extending the service life of the second blade 300.

[0051] In an embodiment of the present invention, with reference to Figure 2 and Figure 3, a chip discharging surface 140 is further provided between two adjacent first mounting surfaces 130. The chip discharging surface 140 is arranged to sink relative to the outer wall of the tool shank 100, and the sinking depth of the chip discharging surface 140 gradually increases from the mounting end 110 to the connecting end 120. The chip discharging surface 140 is provided between two adjacent first mounting surfaces 130, so that the chips generated by the cutting of the first cutting blade 200 can be discharged out of the milling cutter in time from the chip discharging surface 140, avoiding the cutting sticking to the first cutting blade 200; the sinking depth of the chip discharging surface 140 gradually increases from the mounting end 110 to the connecting end 120, which is beneficial to the discharge of the chips and speeds up the discharge rate of the chips.

[0052] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the content of the specification and drawings of the present invention under the inventive concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A milling cutter, characterized in that, The milling cutter includes a tool shank, the tool shank has an installation end and a connection end which are arranged back to back, and a plurality of first installation surfaces are arranged at intervals along the circumferential direction of the tool shank on the side wall of the installation end; The milling cutter further includes a plurality of first blades, each first blade is installed on one of the first installation surfaces, and each first blade has a cutting edge facing the rotation direction of the tool shank; The milling cutter further includes a plurality of second blades, and the plurality of second blades are arranged at intervals around the central axis of the tool shank on the end face of the installation end, and each second blade has a cutting surface facing the rotation direction of the tool shank; The cutting edge extends along the direction from the installation end to the connection end, and the extension direction of the cutting edge forms an angle with the axis of the tool shank; In the rotation direction of the tool shank, one end of the cutting edge close to the end face of the installation end is arranged in front of one end of the cutting edge far from the end face of the installation end; The first blade includes a first side wall, a second side wall, a third side wall, a fourth side wall, a fifth side wall, a sixth side wall and a seventh side wall which are arranged in sequence along its circumferential direction and are connected in sequence. The first side wall abuts against the first installation surface and is arranged back to back with the fifth side wall. The back direction of the second side wall forms an obtuse angle with the back direction of the first side wall. The third side wall is arranged as a concave curved surface. The back direction of the fourth side wall forms an obtuse angle with the back direction of the fifth side wall. The fourth side wall and the fifth side wall enclose the cutting edge. The distance between the sixth side wall and the first side wall gradually increases along the rotation direction of the tool shank. The seventh side wall is arranged back to back with the fourth side wall.

2. The milling cutter according to claim 1, characterized in that, The first blade is provided with a chip breaker groove, and the chip breaker groove is formed by enclosing the second side wall, the third side wall and the fourth side wall. The notch of the chip breaker groove is arranged towards the rotation direction of the tool shank.

3. The milling cutter according to claim 2, wherein Define the angle between the fourth side wall and the plane where the first side wall is located as α, then α satisfies the condition 45° < α < 90°.

4. The milling cutter according to claim 3, characterized in that, A cutting portion is convexly provided on the end face of the first blade close to the installation end, and the cutting portion and the first blade are of an integrally formed structure.

5. The milling cutter according to claim 4, wherein, The cutting portion includes a top surface facing away from the tool shank, and the height of the top surface gradually increases along the rotation direction of the first blade; And / or, the cutting portion includes a top surface facing away from the tool shank, and the height of the top surface gradually decreases from the center of the tool shank outwards.

6. The milling cutter according to claim 1, characterized in that, The second blade includes a cutting surface, a second side wall, a third side wall, a fourth side wall, a fifth side wall and a sixth side wall which are arranged in sequence along its circumferential direction and are connected in sequence. The cutting surface is arranged back to back with the fifth side wall. The second side wall is arranged back to back with the sixth side wall. The third side wall and the fourth side wall form an obtuse angle. The back direction of the fourth side wall forms an acute angle with the back direction of the fifth side wall; The second blade further includes a second installation surface facing the installation end and a top wall facing the facing direction of the installation end. The second installation surface abuts against the end face of the installation end, and the top wall is arranged back to back with the second installation surface.

7. The milling cutter according to claim 6, characterized in that, The height of the top wall gradually increases along the rotation direction of the milling cutter.

8. The milling cutter according to claim 1, characterized in that, A chip discharging surface is further provided between two adjacent first mounting surfaces. The chip discharging surface is sunken relative to the outer wall of the tool shank, and the sinking depth of the chip discharging surface gradually increases from the mounting end to the connecting end.

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