Milling blade with double-layer sleeking structure

Abstract

The invention discloses a milling blade with a double-layer sleeking structure, and belongs to the field of metal cutting machining, the milling blade comprises an upper surface, a lower bottom surface and a peripheral surface, the peripheral surface comprises two side surfaces and two end surfaces, a main cutting edge is formed at the intersection part of the upper surface and the side surfaces, and a main cutting edge is formed at the intersection part of the lower bottom surface; a main sleeking edge, a clearance groove, an auxiliary sleeking edge and an auxiliary cutting edge are sequentially formed in the intersection position of the upper surface and the at least one end surface in the direction away from the main cutting edge. In the cutting machining process, under the condition that the quality of the machined surface is affected due to the fact that the main sleeking edge is provided with a notch or cracks, the auxiliary sleeking edge can conduct secondary sleeking machining on the machined surface so as to supplement the sleeking machining function lacked by the blade body, and then the machining precision of the surface can be continuously maintained. The effective machining time is prolonged due to continuous use of the milling blade, which means that the service life of the milling blade is also prolonged.

Description

Technical Field

[0001] The invention belongs to the field of metal cutting and processing, in particular to a milling blade with a double-layer finishing structure. Background Art

[0002] In the field of metal cutting processing with CNC tools, plane milling is a relatively common processing method, which removes metal materials by making regular reciprocating motions in the plane with a high-speed rotating tool. In plane milling, surface quality is one aspect of examining whether the workpiece processing is qualified. In addition to the machine tool processing parameters, workpiece materials, and tooling matching accuracy, it is also related to the degree of wear of the blade wiper edge, which means that the blade wiper edge plays an important role in the entire metal removal process. Failure of the wiper edge means that the accuracy of the machined surface cannot be maintained, and the blade will not continue to be used. Only when the wiper edge remains intact can the workpiece continue to obtain a relatively ideal surface quality.

[0003] The patent with publication number CN113573834A discloses a cutting blade, in which the width of the first surface increases as it moves from the middle position toward the front end side, thereby ensuring the strength of the blade tip; the width decreases as it moves from the front end side toward the middle position, thereby suppressing the wear of the back gap surface; the width increases as it moves from the middle position toward the rear end side, thereby preventing interference with the workpiece; and the two-point contact between the second surface and the blade body can improve the installation accuracy of the blade body.

[0004] In the above scheme, ensuring the tip strength of the cutting blade and improving the installation accuracy can improve the surface processing quality of the workpiece to a certain extent. However, the wiper blade as the third cutting edge of the cutting blade still adopts a more traditional single-edge structure. In plane processing, the wiper blade will always be in direct contact with the workpiece and participate in the polishing process, which plays a role in improving and repairing the surface quality. The wiper blade of this traditional structure is prone to damage due to the combined effect of cutting heat and cutting force during the cutting process. As the cutting process proceeds, the degree of damage will be further aggravated, the role of the wiper blade will be reduced, and the processing accuracy of the workpiece surface will be affected to a certain extent. Summary of the invention

[0005] The object of the present invention is to provide a milling insert with a double-layer finishing structure to solve the above-mentioned problems in the prior art.

[0006] Provided is a milling insert with a double-layer finishing structure, comprising:

[0007] The blade body has at least one main cutting edge, and the blade body is formed with a main finishing edge, a clearance groove, a secondary finishing edge and a secondary cutting edge in sequence along the direction away from the main cutting edge, the main finishing edge is connected with the adjacent main cutting edge through the main cutting tip, and the secondary finishing edge is connected with the adjacent main cutting edge through the secondary cutting tip.

[0008] As a further embodiment of the present invention: the main finishing edge and the secondary finishing edge are parallel to each other, the length of the main finishing edge is L1, the length of the secondary finishing edge is L2, and L1≤L2.

[0009] As a further embodiment of the present invention: the blade body includes an upper surface, a lower bottom surface and surrounding surfaces, the surrounding surfaces include two side surfaces and two end surfaces, the portion where the end surface is adjacent to the main finishing edge forms a main finishing edge, the portion where the end surface is adjacent to the secondary finishing edge forms a secondary finishing edge, and the air avoidance groove is formed by the end surface being located between the main finishing edge and the secondary finishing edge.

[0010] As a further embodiment of the present invention: the portion where the end surface is adjacent to the main trimming back angle surface and the avoidance groove is recessed inwardly relative to the main trimming back angle surface to form a main trimming gap surface, and the portion where the end surface is adjacent to the secondary trimming back angle surface and the avoidance groove is recessed inwardly relative to the secondary trimming back angle surface to form a secondary trimming gap surface.

[0011] As a further embodiment of the present invention: the plane where the main trimming back angle surface is located is parallel to the plane where the secondary trimming back angle surface is located, there is a distance difference H1 between the main trimming back angle surface and the secondary trimming back angle surface, and 0.03mm≤H1≤0.1mm.

[0012] As a further embodiment of the present invention: the blade body includes an upper surface, a lower bottom surface and surrounding surfaces, the surrounding surfaces include two side surfaces and two end surfaces, a screw through hole is penetrated inside the blade body between the upper surface and the lower bottom surface, the two side surfaces are rotationally symmetrically arranged relative to the central axis of the screw through hole, and the two end surfaces are rotationally symmetrically arranged relative to the central axis of the screw through hole.

[0013] As a further embodiment of the present invention: the extension lines of the two main wiper edges and the extension lines of the two secondary wiper edges are both located on a radial plane of the central axis of the same screw through hole.

[0014] As a further embodiment of the present invention: when the main cutting edge extends from the main cutting edge to the secondary cutting edge, the main cutting edge gradually inclines toward the lower bottom surface; when the secondary cutting edge extends from the secondary finishing edge to the secondary cutting edge, the secondary cutting edge gradually inclines toward the lower bottom surface.

[0015] As a further embodiment of the present invention: it also includes a tool rod and a locking screw, the blade body includes an upper surface, a lower bottom surface and surrounding surfaces, the surrounding surfaces include two side surfaces and two end surfaces, a screw through hole is penetrated inside the blade body between the upper surface and the lower bottom surface, a tool groove is arranged in the side mounting groove of the tool rod, the tool groove includes an end support surface, a side support surface, a bottom support surface and a screw countersunk hole, the portion where the end surface is adjacent to the auxiliary cutting edge forms an end positioning surface, the portion where the side surface is adjacent to the lower bottom surface is recessed inward to form a side positioning surface, after the screw through hole of the blade body and the screw countersunk hole of the tool rod are matched with each other through the locking screw, the lower bottom surface abuts against the bottom support surface, the side positioning surface abuts against the side support surface, and the end positioning surface abuts against the end support surface.

[0016] As a further embodiment of the present invention: the cutting end face of the tool rod forms a chip removal groove extending in an arc shape, one end of the chip removal groove is connected to the air avoidance groove, and the other end is connected to the side mounting groove of the tool rod.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. In the cutting process, the main tool tip and the main cutting edge are the main participants in the cutting process, and the main finishing blade plays a finishing role on the machined surface to improve the quality of the machined surface. Although the main finishing blade does not directly participate in the cutting, due to the existence of manufacturing errors, the main finishing blade will also be affected by some cutting resistance and cutting heat, and it is easy to be damaged. When the main finishing blade has a notch or crack that has affected the quality of the machined surface, the secondary finishing blade can perform secondary finishing on the machined surface to supplement the finishing function missing from the blade body, thereby continuously maintaining the surface processing accuracy. The continued use of the milling insert will extend the effective processing time, which means that the service life of the milling insert is also increased.

[0019] 2. The setting of the avoidance groove isolates the main trimming edge from the secondary trimming edge to prevent the adverse effects of cutting resistance and cutting heat on the main trimming edge from being transmitted to the secondary cutting edge, effectively protecting the structural stability of the secondary cutting edge. When the main trimming edge and the secondary trimming edge are trimmed, the generated debris can be discharged through the avoidance groove to prevent the debris from continuously accumulating on the surface of the main cutting edge and the secondary cutting edge, causing the cutting edge to wear. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present drawings or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present drawings. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the blade body provided by the present invention;

[0022] Figure 2 is a front view of the blade body provided by the present invention;

[0023] Figure 3 is a top view of the blade body provided by the present invention;

[0024] Figure 4 yes Figure 3 Cross-sectional view of the middle DD;

[0025] Figure 5 is a side view of a blade body provided by the present invention;

[0026] Figure 6 It is a partial enlarged view of the wiper blade in the present invention;

[0027] Figure 7 is an assembly diagram of a cutting tool provided by the present invention;

[0028] Figure 8 It is a structural schematic diagram of the knife bar provided by the present invention;

[0029] Fig. 9 It is a schematic diagram of the cutting state of the blade body provided by the present invention;

[0030] Fig.10 yes Fig. 9 A partial enlarged view of the cutting state of the middle blade body;.

[0031] In the figure: 1, blade body; 5, upper surface; 6, lower bottom surface; 7, surrounding surface; 8, screw through hole; 10, end surface; 11, side surface; 12, main cutting edge; 16, main tool tip; 18, main finishing edge; 19, main finishing back angle surface; 20, avoidance groove; 22, main finishing clearance surface; 23, secondary finishing clearance surface; 25, secondary cutting edge; 26, secondary tool tip; 28, secondary finishing edge; 29, secondary finishing back angle surface; 30, end positioning surface; 40, end support surface; 41, side support surface; 42, bottom support surface; 44, tool groove; 46, screw countersunk hole; 50, locking screw; 60, tool bar; 61, chip groove; 100, cutting tool; 110, main cutting back angle surface; 112, side positioning surface; 113, main cutting clearance surface; 200, workpiece. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0033] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can also be applied to other similar scenarios based on these drawings without creative work. In addition, it can also be understood that although the efforts made in this development process may be complicated and lengthy, for ordinary technicians in this field related to the content disclosed by the present invention, some changes in design, manufacturing or production based on the technical content disclosed by the present invention are just conventional technical means, and should not be understood as insufficient content disclosed by the present invention.

[0034] However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repeated descriptions of substantially the same structures may be omitted. This is to avoid the following description from becoming unnecessarily lengthy and to facilitate understanding by those skilled in the art. In addition, the drawings and the following description are provided to enable those skilled in the art to fully understand the present invention and are not intended to limit the subject matter described in the claims.

[0035] See also Figure 1 and Figure 3 As shown, the milling insert with a double-layer finishing structure in the embodiment of the present invention comprises an upper surface 5, a lower bottom surface 6 and a peripheral surface 7. The upper surface 5 and the lower bottom surface 6 are connected by the peripheral surface 7 to form an insert body 1. The peripheral surface 7 comprises two side surfaces 11 and two end surfaces 10. The intersection of the upper surface 5 and the side surface 11 forms a main cutting edge 12. The intersection of the upper surface 5 and at least one end surface 10 forms a main finishing edge 18, a clearance groove 20, a secondary finishing edge 28 and a secondary cutting edge 25 in sequence in a direction away from the main cutting edge 12. The main finishing edge 18 is connected to the adjacent main cutting edge 12 by the main tool tip 16, and the secondary finishing edge 28 is connected to the adjacent main cutting edge 12 by the secondary tool tip 26. A screw through hole 8 runs through the insert body 1 between the upper surface 5 and the lower bottom surface 6.

[0036] In the prior art, the processed surface may be squeezed and deformed, and burrs and scratches may occur, which may affect the surface processing quality. When the conventional blade wiper edge is further damaged, the possibility of surface defects will increase. Through the implementation of the present invention, the secondary wiper edge 28 is set behind the main wiper edge 18 for cutting, and the surface processed by the main wiper edge 18 can be polished again, so as to remove excess residual materials on the surface of the workpiece 200 to the maximum extent, make up for the loss of surface accuracy, and further improve the quality of the processed surface.

[0037] See also Figure 1-Figure 4 , Figure 7-Figure 9 As shown, the milling blade also includes a shank 60 and a locking screw 50. In this embodiment, the cutting end of the shank 60 is rotationally symmetrically arranged with two open side mounting grooves, and a knife groove 44 is provided in the side mounting groove. The knife groove 44 is used to cooperate with the blade body 1 to form a complete cutting tool 100. The knife groove 44 includes an end support surface 40, a side support surface 41, a bottom support surface 42 and a screw countersunk hole 46. The assembly method of the cutting tool 100 is to place the locking screw 50 in the screw through hole 8 of the blade body 1, and fix the blade body 1 in the knife groove 44 through the screw countersunk hole 46. The cutting tool 100 can rotate at high speed around the tool rotation center C to perform plane cutting processing on the workpiece 200.

[0038] The lower bottom surface 6 is a positioning base surface, which contacts the bottom support surface 42 after assembly. The bottom support surface 42 provides sufficient bottom support force for the blade body 1.

[0039] The part where the side surface 11 and the lower bottom surface 6 are adjacent to each other is recessed inward to form a side positioning surface 112. The convex part of the side surface 11 relative to the side positioning surface 112 is the main cutting back angle surface 110. The part where the side positioning surface 112 and the main cutting back angle surface 110 are connected is the main cutting clearance surface 113. The main cutting clearance surface 113 makes the bevel transition between the side positioning surface 112 and the main cutting back angle surface 110. The side positioning surface 112 can be a blank surface, which contacts the side support surface 41 to provide side positioning for the blade body 1. The side support surface 41 provides side support force for the blade body 1. The extension structure of the main cutting clearance surface 113 is used to protect the side positioning surface 112 from cutting wear and ensure the positioning accuracy of the blade body 1. The main cutting back angle surface 110 has a certain thickness, which can improve the structural strength of the main cutting edge 12, avoid wear of the main cutting edge 12, and improve its durability.

[0040] The portion where the end surface 10 and the secondary cutting edge 25 are adjacent to each other forms an end positioning surface 30. The end positioning surface 30 contacts the end support surface 40 to provide end surface positioning for the insert body 1. The end support surface 40 provides end surface support force for the insert body 1.

[0041] The portion where the end surface 10 is adjacent to the main trimming edge 18 forms a main trimming back angle facet 19, and the portion where the end surface 10 is adjacent to the secondary trimming edge 28 forms a secondary trimming back angle facet 29. The air-avoiding groove 20 is formed by the portion of the end surface 10 located between the main trimming back angle facet 19 and the secondary trimming back angle facet 29 being recessed inward. The main trimming back angle facet 19 and the secondary trimming back angle facet 29 need to be ground to provide a trimming structure with higher precision. The main trimming back angle facet 19 provides a certain structural strength support for the main trimming edge 18 through its own thickness, thereby improving the wear resistance of the main trimming edge 18. Similarly, the secondary trimming back angle facet 29 provides a certain structural strength support for the secondary trimming edge 28 through its own thickness, thereby improving the wear resistance of the secondary trimming edge 28.

[0042] Furthermore, the portion of the end surface 10 adjacent to the main trimming back angle surface 19 and the air-avoiding groove 20 is recessed inward relative to the main trimming back angle surface 19 to form a main trimming gap surface 22. The main trimming gap surface 22 reduces the area occupied by the main trimming back angle surface 19 on the end surface 10, avoids excessive friction interference with the workpiece 200 due to the main trimming back angle surface 19 being too large, and reduces cutting resistance and cutting heat. In fact, the main trimming back angle surface 19 does not need to occupy the entire thickness range of the end surface 10, and can provide a certain thickness size as a support structure for the main trimming edge 18. Secondly, the air-avoiding treatment of the main trimming gap surface 22 can facilitate the discharge of debris in the backward direction.

[0043] When the primary polishing edge 18 is damaged, the secondary polishing edge 28 participates in the secondary polishing process. The portion of the end surface 10 adjacent to the secondary polishing back angle surface 29 and the air-avoiding groove 20 is recessed inward relative to the secondary polishing back angle surface 29 to form a secondary polishing clearance surface 23. The secondary polishing clearance surface 23 reduces the area occupied by the secondary polishing back angle surface 29 on the end surface 10, avoids excessive friction interference between the secondary polishing back angle surface 29 and the workpiece 200 due to the excessive area of ​​the secondary polishing back angle surface 29, and reduces the cutting resistance and cutting heat. Similarly, the secondary polishing back angle surface 29 does not need to occupy the entire thickness range of the end surface 10, and can provide a certain thickness size as a supporting structure of the secondary polishing edge 28. Secondly, the air-avoiding treatment of the secondary polishing clearance surface 23 can facilitate the discharge of debris to the side.

[0044] The protruding structures of the main polishing back angle surface 19 and the secondary polishing back angle surface 29 respectively compared with the main polishing gap surface 22 and the secondary polishing gap surface 23 provide a basis for secondary grinding of the main polishing back angle surface 19 and the secondary polishing back angle surface 29, thereby improving the reuse rate of the blade body 1.

[0045] See also Figure 3As shown, the main polishing edge 18 and the secondary polishing edge 28 are parallel to each other to avoid local stress concentration caused by blade angle deviation in the processing direction, which aggravates the wear of the polishing edge. In order to ensure that the secondary polishing range of the secondary polishing edge 28 can cover the polishing range of the main polishing edge 18, the length L1 of the main polishing edge 18 is not greater than the length L2 of the secondary polishing edge 28, that is, L1≤L2. Ensure that the secondary polishing edge 28 can completely cover the surface processing range of the main polishing edge 18 under large feed conditions.

[0046] See also Figure 1 , Figure 6 , Fig.10 As shown, the plane where the main trimming back angle surface 19 is located is parallel to the plane where the secondary trimming back angle surface 29 is located, so as to avoid local stress concentration caused by plane angle deviation in the processing direction, which aggravates the wear of the trimming back angle surface. In the cutting process of the workpiece 200, the main trimming edge 18 contacts the surface of the workpiece 200 first. When the main trimming edge 18 is not completely damaged, the secondary trimming edge 28 is in a non-processing state, and is at a certain distance H1 from the surface processed by the main trimming edge 18, and is in self-protection. When the main trimming edge 18 is damaged and burrs and scratches appear on the processed surface, the secondary trimming edge 28 will participate in the trimming process to remove the processing residues on the surface. Therefore, in the top view direction of the upper surface 5, the main finishing edge 18 and the secondary finishing edge 28 are not collinear, the secondary finishing edge 28 is closer to the screw through hole 8 than the main finishing edge 18, there is a distance difference H1 between the main finishing edge 19 and the secondary finishing edge 29, and 0.03mm≤H1≤0.1mm. This range ensures that the secondary finishing edge 28 does not participate in the secondary finishing when the main finishing edge 18 is not completely damaged, and has a protective effect on the secondary finishing edge 28; and when the main finishing edge 18 fails, it ensures that the secondary finishing edge 28 can respond quickly to participate in the secondary finishing. In this embodiment, H1 is preferably 0.05mm.

[0047] In one embodiment, see Figure 1 , Figure 3 and Figure 8 As shown, the blade body 1 can be provided with the main polishing edge 18 and the secondary polishing edge 28 only on a single end surface 10, or can be provided with the main polishing edge 18 and the secondary polishing edge 28 on both end surfaces 10. The two side surfaces 11 are arranged rotationally symmetrically with respect to the central axis A of the screw through hole 8, and the two end surfaces 10 are arranged rotationally symmetrically with respect to the central axis A of the screw through hole 8, so that the blade body 1 can be indexed and processed, and the processing surface of the blade body 1 can be replaced in the tool groove 44, thereby improving the reuse rate of the blade body 1.

[0048] For further information, see Figure 1 and Figure 5As shown, the extension lines of the two main finishing edges 18 and the extension lines of the two secondary finishing edges 28 are all located on the radial plane of the central axis A of the same screw through hole 8, that is, H2 = 0. When grinding the lower bottom surface 6, the lower bottom surface 6 needs to be facing upward and the main tool tip 16 needs to be facing downward. The two main finishing edges 18 and the two secondary finishing edges 28 are located in the same plane, which can provide stable support for the blade body 1, improve the grinding accuracy of the lower bottom surface 6, and ensure the transposition accuracy of the main tool tip 16 and other structures when the blade body 1 is subjected to indexing processing to replace the processing surface.

[0049] See also Figure 2 As shown, when the main cutting edge 12 extends from the main tool tip 16 to the secondary tool tip 26, the main cutting edge 12 gradually tilts toward the lower bottom surface 6. That is, H3>H4, so that the main cutting edge 12 tilts to form an inclination angle α, which is used to form an escape area to guide the chip flow and keep the chips away from the machined surface.

[0050] See also Figure 5 As shown, when the secondary cutting edge 25 extends from the secondary polishing edge 28 toward the secondary cutting edge 26, the secondary cutting edge 25 gradually tilts toward the lower bottom surface 6. That is, H3>H4, and similarly, it is used to form an escape area to facilitate chip discharge.

[0051] See also Figure 1 , Figure 8 and Fig. 9 As shown, the cutting end face of the tool bar 60 forms a circular arc-shaped chip groove 61, one end of the chip groove 61 is connected to the air-avoiding groove 20, and the other end is connected to the side mounting groove of the tool bar 60. The chips generated when the main polishing edge 18 and the secondary polishing edge 28 are polished can enter the air-avoiding groove 20, pass through the chip groove 61, and then be discharged to the side mounting groove, and finally discharged from the side mounting groove. The circular arc structure can avoid the occurrence of chip removal dead corners that cause chip accumulation.

[0052] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and embodiments having substantially the same structure as the technical idea and exerting the same effects within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, within the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments, and other methods of combining some of the constituent elements in the embodiments to construct are also included in the scope of the present invention.

Claims

1. A milling insert with a double-layer finishing structure, characterized in that: include: A blade body (1), wherein the blade body (1) has at least one main cutting edge (12), and the blade body (1) is formed with a main finishing edge (18), a clearance groove (20), a secondary finishing edge (28) and a secondary cutting edge (25) in sequence in a direction away from the main cutting edge (12); the main finishing edge (18) is connected to an adjacent main cutting edge (12) via a main cutting edge (16), and the secondary finishing edge (28) is connected to an adjacent main cutting edge (12) via a secondary cutting edge (26).

2. The milling insert with a double-layer finishing structure according to claim 1, characterized in that: The main finishing edge (18) and the secondary finishing edge (28) are parallel to each other, the length of the main finishing edge (18) is L1, the length of the secondary finishing edge (28) is L2, and L1≤L2.

3. The milling insert with a double-layer finishing structure according to claim 1, characterized in that: The blade body (1) comprises an upper surface (5), a lower bottom surface (6) and surrounding surfaces (7); the surrounding surfaces (7) comprise two side surfaces (11) and two end surfaces (10); the portion where the end surface (10) adjoins the main finishing edge (18) forms a main finishing back angle surface (19); the portion where the end surface (10) adjoins the secondary finishing edge (28) forms a secondary finishing back angle surface (29); the air avoidance groove (20) is formed by an inward depression of a portion of the end surface (10) located between the main finishing back angle surface (19) and the secondary finishing back angle surface (29).

4. The milling insert with a double-layer finishing structure according to claim 3, characterized in that: The portion where the end surface (10) adjoins the main trimming rear angle surface (19) and the avoidance groove (20) is recessed inwardly relative to the main trimming rear angle surface (19) to form a main trimming clearance surface (22), and the portion where the end surface (10) adjoins the secondary trimming rear angle surface (29) and the avoidance groove (20) is recessed inwardly relative to the secondary trimming rear angle surface (29) to form a secondary trimming clearance surface (23).

5. The milling insert with a double-layer finishing structure according to claim 3, characterized in that: The plane where the main trimming rear angle surface (19) is located and the plane where the secondary trimming rear angle surface (29) is located are parallel to each other, and there is a distance difference H1 between the main trimming rear angle surface (19) and the secondary trimming rear angle surface (29), and 0.03mm≤H1≤0.1mm.

6. The milling insert with a double-layer finishing structure according to claim 1, characterized in that: The blade body (1) comprises an upper surface (5), a lower bottom surface (6) and surrounding surfaces (7), the surrounding surfaces (7) comprising two side surfaces (11) and two end surfaces (10), a screw through hole (8) passes through the blade body (1) between the upper surface (5) and the lower bottom surface (6), the two side surfaces (11) are arranged rotationally symmetrically with respect to the central axis of the screw through hole (8), and the two end surfaces (10) are arranged rotationally symmetrically with respect to the central axis of the screw through hole (8).

7. The milling insert with a double-layer finishing structure according to claim 6, characterized in that: The extension lines of the two main finishing edges (18) and the extension lines of the two secondary finishing edges (28) are both located on a radial plane of the central axis of the same screw through hole (8).

8. The milling insert with a double-layer finishing structure according to claim 6, characterized in that: When the main cutting edge (12) extends from the main cutting edge (16) to the secondary cutting edge (26), the main cutting edge (12) gradually inclines toward the lower bottom surface (6); when the secondary cutting edge (25) extends from the secondary finishing edge (28) to the secondary cutting edge (26), the secondary cutting edge (25) gradually inclines toward the lower bottom surface (6).

9. The milling insert with a double-layer finishing structure according to claim 1, characterized in that: The invention also comprises a blade rod (60) and a locking screw (50), wherein the blade body (1) comprises an upper surface (5), a lower bottom surface (6) and surrounding surfaces (7), wherein the surrounding surfaces (7) comprise two side surfaces (11) and two end surfaces (10), wherein a screw through hole (8) penetrates the interior of the blade body (1) between the upper surface (5) and the lower bottom surface (6), and a blade groove (44) is arranged in the side mounting groove of the blade rod (60), wherein the blade groove (44) comprises an end support surface (40), a side support surface (41), a bottom support surface (42) and a screw countersunk hole ( 46), the portion where the end surface (10) adjoins the secondary cutting edge (25) forms an end positioning surface (30), the portion where the side surface (11) adjoins the lower bottom surface (6) is recessed inward to form a side positioning surface (112), after the screw through hole (8) of the blade body (1) and the screw countersunk hole (46) of the tool rod (60) cooperate with each other through a locking screw (50), the lower bottom surface (6) abuts against the bottom support surface (42), the side positioning surface (112) abuts against the side support surface (41), and the end positioning surface (30) abuts against the end support surface (40).

10. The milling insert with a double-layer finishing structure according to claim 9, characterized in that: The cutting end surface of the tool rod (60) forms a chip removal groove (61) extending in an arc shape, one end of the chip removal groove (61) is connected to the clearance groove (20), and the other end is connected to the side mounting groove of the tool rod (60).

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