Indexable milling insert and rotary tool thereof

Abstract

The utility model relates to a kind of indexable milling inserts and rotary cutters thereof, the indexable milling insert includes insert body, the insert body includes upper top surface, lower bottom surface and the multiple groups of side surfaces extending between upper top surface and lower bottom surface, adjacent side surfaces are transitioned by circular arc surface, the center of insert body is equipped with positioning hole, multiple groups of side surfaces are centrally symmetric relative to positioning hole setting, the included angle of each side surface with the axis of positioning hole is α, 10 °≤α≤20 °.Indexable milling insert adopts multi-section cutting edge, while changing main bias angle, greatly improve the heat transfer, heat dissipation condition of blade edge, reduce the milling force along axial direction into machine tool spindle, thereby reduce the risk of vibration, make processing more stable, and because increase the contact line length of cutting edge and workpiece, reduce the stress of blade edge, thus improve the life of tool. By reducing radial cutting force, reduce vibration and spindle deflection, ensure the stable contact of insert and part.

Description

Technical Field

[0001] This utility model relates to the field of cutting tool technology, specifically to an indexable milling insert and its rotary cutting tool. Background Technology

[0002] Currently, high-feed milling is mainly used in face milling, and also performs well in profile milling, helical interpolation milling, and plunge milling. It has a wide range of applications in the milling of light alloys and steel. With the globalization of industry, metal cutting technology, as the core of modern manufacturing, must meet the requirements of the machinery manufacturing industry and improve processing efficiency. This also places higher technical demands on the performance of high-feed milling tools. The basic principle of high-feed milling is to change the principal cutting edge angle of the tool, using a smaller axial depth of cut to form thinner chips. These chips can carry away a large amount of cutting heat from the cutting edge, thereby extending tool life and improving metal removal rate. The feed per tooth in high-feed milling can typically be more than five times that of conventional milling.

[0003] Traditional high-feed cutting tools typically use ordinary straight-edged inserts with a different principal cutting edge angle for machining (see reference). Figure 6 As shown in the figure, when the principal cutting edge angle θ is too large, a large radial cutting force will be generated, which is prone to vibration; when the principal cutting edge angle θ is too small, the maximum cutting depth will be small, resulting in a small metal removal rate and reduced processing efficiency. Utility Model Content

[0004] This utility model addresses existing technical problems by providing an indexable milling insert and its rotating tool.

[0005] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: An indexable milling insert includes an insert body, the insert body includes an upper top surface, a lower bottom surface and a plurality of side surfaces extending between the upper top surface and the lower bottom surface, adjacent side surfaces are transitioned by arc surfaces, a positioning hole is provided at the center of the insert body, the plurality of side surfaces are centrally symmetrically arranged with respect to the positioning hole, and the angle between each side surface and the axis of the positioning hole is α, 10°≤α≤20°.

[0006] Based on the above technical solution, the present invention can be further improved as follows: Preferably, the side surface is provided in three groups, each group of side surfaces including side surface one, side surface two, side surface three and side surface four arranged in sequence, the intersection line of the upper top surface and side surface three forms cutting edge one, and the intersection line of the upper top surface and side surface four forms cutting edge two.

[0007] Preferably, a support platform is provided on the upper top surface at the intersection of the side surface and the upper top surface.

[0008] Preferably, the intersection line of the top surface and the second side surface forms a finishing blade.

[0009] Preferably, the principal cutting edge angle corresponding to the first cutting edge is Kr1, where 10°≤Kr1≤15°.

[0010] Preferably, the principal cutting edge angle corresponding to the second cutting edge is Kr2, where 20°≤Kr2≤25°.

[0011] Preferably, the junction of the top surface and the side surface is provided with a negative chamfer, the width L of the negative chamfer is 0.15mm≤L≤0.25mm, and the angle β is 10°≤β≤25°.

[0012] This utility model also discloses a rotary cutting tool, including a rotary cutting tool body and the indexable milling insert mentioned above. The rotary cutting tool body is provided with a plurality of insert grooves, which are arranged along the circumference of the rotary cutting tool body and correspond to the indexable milling insert.

[0013] Preferably, the blade groove includes a first positioning surface at the bottom and a second and a third positioning surface on the side. The first positioning surface is in contact with the bottom surface, the second positioning surface is in contact with one set of the side surfaces, and the third positioning surface is in contact with the other set of the side surfaces. The blade body is mounted on the blade groove by a locking screw.

[0014] Preferably, a pressure plate is installed on the blade groove, and the pressure plate presses against the support platform of the blade body.

[0015] The beneficial effects of this invention are as follows: The indexable milling insert adopts a multi-segment cutting edge, which greatly improves the heat transfer and dissipation conditions of the cutting edge while changing the principal cutting edge angle, reduces the milling force transmitted axially to the machine tool spindle, thereby reducing the risk of vibration and making the machining process smoother. Furthermore, by increasing the contact line length between the cutting edge and the workpiece, the stress on the cutting edge is reduced, thus increasing the tool life. By reducing radial cutting force, vibration and spindle misalignment are reduced, ensuring stable contact between the insert body and the workpiece, guaranteeing machining quality, and improving machining efficiency. Attached Figure Description

[0016] Figure 1 This is a three-dimensional schematic diagram of the indexable milling insert of this utility model; Figure 2 This is a partial schematic diagram of the blade groove of this utility model.

[0017] Figure 3 This is a schematic diagram of the rotary cutting tool of this utility model.

[0018] Figure 4 This utility model Figure 3Schematic diagram of the cross section at point AA; Figure 5 This is a schematic diagram of the forces acting on this utility model; Figure 6 This is a schematic diagram of the principal cutting edge angle of a cutting tool in the prior art.

[0019] The attached diagram is labeled as follows: 1. Top surface; 2. Bottom surface; 3. Positioning hole; 4. Support platform; 5. Side 1; 6. Side 2; 7. Side 3; 8. Side 4; 9. Finishing edge; 10. Cutting edge 1; 11. Cutting edge 2; 12. Negative chamfer; 13. Chip breaker groove; 14. Tool groove; 15. First positioning surface; 16. Second positioning surface; 17. Third positioning surface; 18. Locking screw; 19. Pressure plate; 20. Rotating tool body. Detailed Implementation

[0020] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0021] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The terms "vertical," "upper," "lower," "horizontal," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, 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.

[0022] like Figures 1 to 5As shown, the present utility model discloses an indexable milling insert, comprising an insert body. The insert body is formed by pressing cemented carbide powder, sintered and shrunk at high temperature in a sintering furnace, and then formed after finish machining and coating. The insert body comprises an upper top surface 1, a lower bottom surface 2 and a plurality of sets of side surfaces extending between the upper top surface 1 and the lower bottom surface 2. Adjacent said side surfaces are transitioned through arc surfaces, which can enhance tip strength and improve the roughness of the machined surface. A positioning hole 3 is provided at the center of the insert body, and the plurality of sets of said side surfaces are arranged centrosymmetrically with respect to the positioning hole 3. The included angle between each side surface and the axis of the positioning hole 3 is the same, and the included angle between each said side surface and the axis of said positioning hole 3 is α, 10°≤α≤20°. When α is less than 10°, an excessively small α results in a large contact area between the flank face and the workpiece, which accelerates tool wear and affects the service life of the tool; when α is greater than 20°, an excessively large α leads to a decrease in cutting edge strength, and chipping or breakage is prone to occur especially in high-feed machining with large cutting thickness. By setting an appropriate α value, the insert body can maintain stable cutting performance when mounted on a rotating tool, and at the same time, it is convenient to replace and adjust the cutting angle of the insert.

[0023] In this embodiment, three sets of side surfaces are provided, each set of said side surfaces comprises a first side surface 5, a second side surface 6, a third side surface 7 and a fourth side surface 8 arranged in sequence. The intersection line of said upper top surface 1 and said third side surface 7 forms a first cutting edge 10, the entering angle corresponding to said first cutting edge 10 is Kr1, 10°≤Kr1≤15°. The intersection line of said upper top surface 1 and said fourth side surface 8 forms a second cutting edge 11, the entering angle corresponding to said second cutting edge 11 is Kr2, 20°≤Kr2≤25°. That is, the insert body adopts segmented cutting edges, which can reduce the radial component force Fr of the cutting force F (as Figure 5 shown), where Fa=F×cos(Kr), Fr=F×sin(Kr); since sin(Kr)<<cos(Kr), therefore, Fr<<Fa. By making the cutting force received mainly distributed in the axial direction, the axial component force Fa is increased, vibration is reduced, the contact line length between the cutting edge and the part is increased, the stress on the cutting edge is reduced, and the service life of the tool is improved.

[0024] A support table 4 is provided on said upper top surface 1 at the intersection of said first side surface 5 and said upper top surface 1. In this embodiment, three support tables 4 are uniformly provided along the circumferential direction of the upper top surface 1. Since high-feed machining has a certain entering angle, a large axial component force Fa is generated during machining, so the locking screw 18 installed in the positioning hole 3 has to bear a large shearing force. By providing the support tables 4 for supporting the pressure plate 19, in use, dual locking of the insert body by the pressure plate 19 and the locking screw 18 is realized, making the installation of the insert body more firm.

[0025] Furthermore, a chip breaking groove 13 is provided on the upper top surface 1. During the cutting process, the chip breaking groove 13 can subject the chip to additional bending stress, thereby causing the chip to automatically break at a certain length, making it easier to remove the chip.

[0026] The intersection line of the top surface 1 and the second side surface 6 forms a finishing edge 9. This makes the machining process smoother and can improve the surface quality of the machined workpiece and reduce roughness. Furthermore, since this indexable milling insert is a polygonal insert with three cutting edge types: finishing edge 9, cutting edge 10, and cutting edge 2 11, it has excellent chip removal performance.

[0027] A negative chamfer 12 is provided at the junction of the top surface 1 and each of the side surfaces. The width L of the negative chamfer 12 is 0.15mm ≤ L ≤ 0.25mm, and the angle β is 10° ≤ β ≤ 25°. The cutting edge needs to be rounded and dulled, with a dulling value of 0.01mm ≤ r ≤ 0.04mm. High feed cutting experiences large cutting forces; the negative chamfer 12 and dulling treatment can strengthen the cutting edge, improve the chipping resistance and impact resistance of the insert body, and further extend the service life of indexable milling inserts.

[0028] This utility model also discloses a rotary cutting tool, including a rotary cutting tool body 20 and the indexable milling inserts mentioned above. The rotary cutting tool body 20 is provided with a plurality of insert grooves 14 and a plurality of chip guide grooves. The plurality of insert grooves 14 are arranged circumferentially along the rotary cutting tool body 20. The insert grooves 14 correspond to the indexable milling inserts, that is, each insert groove 14 is equipped with an indexable milling insert.

[0029] In this embodiment, the rotary tool is a right-hand rotary tool, and the indexable milling insert is mounted on the rotary tool body 20. Specifically, the insert groove 14 includes a first positioning surface 15 located at the bottom and a second positioning surface 16 and a third positioning surface 17 located on the sides. The first positioning surface 15 is in contact with the bottom surface 2, the second positioning surface 16 is in contact with one set of the side surfaces 7, and the third positioning surface 17 is in contact with the other set of side surfaces 7. The insert body is mounted on the insert groove 14 by locking screws 18. A pressure plate 19 is mounted on the insert groove 14 by screws, and the pressure plate 19 presses against the support platform 4 of the insert body. The locking screws 18 make the insert body and the insert groove 14 fit tightly together, and the pressure plate 19 presses against the support platform 4 of the insert body, achieving double locking by the pressure plate 19 and the locking screws 18, making the insert body more securely mounted, reducing the vibration generated by the insert body during cutting, improving the machining quality and the life of the insert body.

[0030] In other alternative embodiments, the rotary tool can also be a left-handed tool, which is a mirror image of the right-handed tool and otherwise the same, and can also achieve the function of large feed cutting.

[0031] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An indexable milling insert, characterized in that, The blade body includes an upper top surface (1), a lower bottom surface (2), and multiple sets of side surfaces extending between the upper top surface (1) and the lower bottom surface (2). Adjacent side surfaces are transitioned by arc surfaces. A positioning hole (3) is provided at the center of the blade body. The multiple sets of side surfaces are arranged in a centrally symmetrical manner with respect to the positioning hole (3). The angle between each side surface and the axis of the positioning hole (3) is α, where 10°≤α≤20°.

2. The indexable milling insert according to claim 1, characterized in that, The side surface is provided in three groups. Each group of the side surface includes side surface one (5), side surface two (6), side surface three (7) and side surface four (8) arranged in sequence. The intersection line of the top surface (1) and the side surface three (7) forms cutting edge one (10), and the intersection line of the top surface (1) and the side surface four (8) forms cutting edge two (11).

3. The indexable milling insert according to claim 2, characterized in that, A support platform (4) is provided on the upper top surface (1) where the side surface (5) intersects with the upper top surface (1).

4. The indexable milling insert according to claim 2, characterized in that, The intersection line of the top surface (1) and the side surface (6) forms a polishing blade (9).

5. The indexable milling insert according to claim 2, characterized in that, The principal cutting edge angle corresponding to the cutting edge (10) is Kr1, 10°≤Kr1≤15°.

6. The indexable milling insert according to claim 2, characterized in that, The principal cutting edge angle corresponding to the second cutting edge (11) is Kr2, 20°≤Kr2≤25°.

7. The indexable milling insert according to claim 1, characterized in that, The top surface (1) and the side surface are provided with negative chamfers (12). The width L of the negative chamfers (12) is 0.15mm≤L≤0.25mm, and the angle β is 10°≤β≤25°.

8. A rotary cutting tool, comprising a rotary cutting body (20), characterized in that, It also includes the indexable milling insert according to any one of claims 1 to 7, wherein the rotating cutter body (20) is provided with a plurality of insert grooves (14), the plurality of insert grooves (14) are arranged circumferentially along the rotating cutter body (20), and the insert grooves (14) correspond to the indexable milling insert.

9. The rotary cutting tool according to claim 8, characterized in that, The blade groove (14) includes a first positioning surface (15) at the bottom, and a second positioning surface (16) and a third positioning surface (17) on the side. The first positioning surface (15) is in contact with the bottom surface (2), the second positioning surface (16) is in contact with one of the three side surfaces (7), and the third positioning surface (17) is in contact with another set of the three side surfaces (7). The blade body is mounted on the blade groove (14) by a locking screw (18).

10. The rotary cutting tool according to claim 9, characterized in that, A pressure plate (19) is installed on the blade groove (14), and the pressure plate (19) presses on the support platform (4) of the blade body.

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