A milling cutter

Abstract

The present invention discloses a milling cutter, which includes a cutting part and a shank part. At least one bottom edge distributed along the radial direction of the milling cutter and at least one spiral peripheral edge extending along the axial direction of the milling cutter are provided on the cutting part. The bottom edge is connected to the peripheral edge. The peripheral edge is formed by the intersection of a spiral chip flute extending from the cutting part along the axial direction of the milling cutter and a peripheral-edge flank. The peripheral-edge flank includes at least a first peripheral-edge flank and a second peripheral-edge flank. Both the first peripheral-edge flank and the second peripheral-edge flank are spiral. The first peripheral-edge flank is a smooth curved surface and is located between the peripheral edge and the second peripheral-edge flank. The second peripheral-edge flank periodically undulates up and down along the extending direction of the peripheral edge. The present invention has the advantages of fast heat dissipation, good cooling effect, long service life and low processing cost, etc.

Description

Technical Field

[0001] The invention mainly relates to the field of metal cutting, and in particular to a milling tool. Background Art

[0002] Titanium alloys and high-temperature alloys have excellent properties such as high strength, good fracture toughness, and corrosion resistance, and are used in many industries such as aerospace, 3C electronics, energy, and shipbuilding. However, the thermal conductivity of these two alloys is low, and there are hard phases in the microstructure. During the machining process, the cutting temperature is high, the cutting force is large, and the work hardening and edge adhesion wear are very serious, resulting in a low cutting life of the machining tool.

[0003] For materials such as titanium alloys and high-temperature alloys that are prone to high temperatures during processing, in order to extend the tool life, the heat generated during the processing must be reduced. Common measures in the existing technology include optimizing processing parameters to reduce cutting forces, surface treatment of the front and rear tool faces to reduce friction coefficients, increasing coolant flow or pressure to accelerate cooling, and optimizing tool structure to improve heat dissipation conditions. In short, improving the heat dissipation capacity of the tool is the fundamental measure to extend the tool life.

[0004] Chinese patent document CN108580999A discloses a ball-end milling cutter specially used for milling thin-walled titanium alloys. The milling cutter has a cross-textured surface on the back face of the ball-end blade at a distance of 0.05 to 0.1 mm from the cutting edge. This bionic structure can reduce the contact area and friction coefficient between the tool and the machined surface, reduce the heat generated during the friction process, and also increase the heat dissipation area of ​​the tool surface, allowing the cutting fluid to take away more heat. However, due to the small size of this texture structure, it is difficult to process and the cost is high to ensure the uniformity and size consistency of the texture.

[0005] In addition, Chinese patent document CN113118531A discloses a general end mill with chip grooves for roughing and finishing. Each cutting edge of the milling cutter is provided with a rectangular chip groove and a half-moon chip groove, which can effectively split a long chip into multiple shorter chips, and the chips generated by different chip grooves have different outflow directions, so that the chips will not accumulate, which is conducive to the heat dissipation of the tool, reduces the cutting resistance, and prolongs the tool life. Although the invention document points out that the milling cutter is suitable for roughing and finishing at the same time, since the chip groove is designed on the main cutting edge, the continuity of the original spiral cutting edge shape is destroyed, resulting in multiple "notches" in the radial direction of the cutting edge. Even if the "notches" of adjacent cutting edges are staggered, the sharp corners of these "notches" will form slight scratches on the processed surface during processing, reducing the quality of the processed surface. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a milling cutter with fast heat dissipation, good cooling effect, long service life and low processing cost.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A milling cutter includes a cutting part and a shank part. At least one bottom edge distributed along the radial direction of the milling cutter and at least one spiral peripheral edge extending along the axial direction of the milling cutter are provided on the cutting part. The bottom edge is connected to the peripheral edge. The peripheral edge is formed by the intersection of a spiral chip flute extending from the cutting part along the axial direction of the milling cutter and the flank face of the peripheral edge. The flank face of the peripheral edge at least includes a first flank face of the peripheral edge and a second flank face of the peripheral edge. Both the first flank face of the peripheral edge and the second flank face of the peripheral edge are spiral. The first flank face of the peripheral edge is a smooth curved surface and is located between the peripheral edge and the second flank face of the peripheral edge. The second flank face of the peripheral edge periodically undulates up and down along the extending direction of the peripheral edge.

[0009] As a further improvement of the above technical solution:

[0010] The intersection line of the first flank face of the peripheral edge and the second flank face of the peripheral edge is a sine curve on the developed plane of the outer cylindrical surface of the shank part.

[0011] On the developed plane of the outer cylindrical surface of the shank part, the common tangent line of all the wave crests on the intersection line of the first flank face of the peripheral edge and the second flank face of the peripheral edge is parallel to the peripheral edge, and the distance between the two is L. The diameter of the milling cutter is D, and it should satisfy: 0.03D ≤ L ≤ 0.08D.

[0012] The groove line of any wave trough on the second flank face of the peripheral edge deviates from the normal direction of the peripheral edge towards the shank part, and the included angle with the normal direction of the peripheral edge is γ. The helix angle of the spiral chip flute is β, and it should satisfy: β ≤ γ ≤ β + 30°.

[0013] The distance d1 between the groove lines of any two adjacent wave troughs on the second flank face of the peripheral edge is the same, and it should satisfy: 0.1D ≤ d1 ≤ 0.3D.

[0014] The distance H between the wave crest and the wave trough on the second flank face of the peripheral edge in the radial direction of the milling cutter should satisfy: 0.01D ≤ H ≤ 0.05D.

[0015] The clearance angle of the first flank face of the peripheral edge is α1, and the clearance angle of the second flank face of the peripheral edge is α2, and it should satisfy: 0 ≤ α1 ≤ 15°, α1 ≤ α2 ≤ 30°.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] The milling cutter of the present invention has a peripheral cutting edge flank that at least includes a first peripheral cutting edge flank and a second peripheral cutting edge flank. Both the first peripheral cutting edge flank and the second peripheral cutting edge flank are helical. The first peripheral cutting edge flank is a smooth curved surface and is located between the peripheral cutting edge and the second peripheral cutting edge flank. The second peripheral cutting edge flank periodically undulates up and down along the extension direction of the peripheral cutting edge, increasing the heat dissipation area of the surface of the milling cutter, facilitating the retention of the coolant, and accelerating the cooling rate of the peripheral cutting edge of the milling cutter. When the milling cutter is used to machine materials with low thermal conductivity such as titanium alloys and superalloys, it can accelerate heat dissipation, avoid the generation of cutting high temperatures, contribute to improving the tool durability, and extend the tool life. At the same time, due to the provision of the first peripheral cutting edge flank which is a smooth curved surface, not only is the processing difficulty of the peripheral cutting edge flank reduced, but also the continuity of the peripheral cutting edge is not damaged, ensuring that the milling cutter of the present invention can also be applied to the finish machining conditions with high requirements for surface machining quality. In addition, since the second peripheral cutting edge flank periodically undulates up and down along the extension direction of the peripheral cutting edge, it can be machined using a formed grinding wheel, with relatively low processing difficulty, reducing the manufacturing cost of the milling cutter. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is the front view of the milling cutter of the present invention.

[0019] Figure 2 is a schematic diagram after the peripheral cutting edge of the milling cutter of the present invention is unfolded on the developed plane of the outer cylindrical surface of the shank.

[0020] Figure 3 is Figure 2 the A-A view in (schematic diagram of the second peripheral cutting edge flank of the milling cutter of the present invention on a cross-section parallel to the peripheral cutting edge).

[0021] Figure 4 is Figure 2 the B-B view in (schematic diagram of the peripheral cutting edge flank of the milling cutter of the present invention on a normal cross-section of the peripheral cutting edge).

[0022] Each reference numeral in the figure represents:

[0023] 1, cutting part; 2, shank; 3, bottom cutting edge; 4, peripheral cutting edge; 5, spiral chip removal groove; 6, peripheral cutting edge flank; 61, first peripheral cutting edge flank; 62, second peripheral cutting edge flank; 7, intersection line of the first peripheral cutting edge flank and the second peripheral cutting edge flank; 8, outer cylindrical surface; 9, common tangent of the wave crest; 10, groove line of the wave trough; 11, rotation center axis. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The present invention will be further described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0025] Figures 1 to 4An embodiment of the milling cutter of the present invention is shown. The milling cutter of this embodiment includes a cutting part 1 and a shank part 2. At least one bottom edge 3 distributed radially along the milling cutter and at least one helical peripheral edge 4 extending axially along the milling cutter are provided on the cutting part 1. The bottom edge 3 is connected to the peripheral edge 4. The peripheral edge 4 is formed by the intersection of a helical chip groove 5 extending axially from the cutting part 1 to the shank part 2 and a peripheral-edge flank 6. The peripheral-edge flank 6 at least includes a first peripheral-edge flank 61 and a second peripheral-edge flank 62. Both the first peripheral-edge flank 61 and the second peripheral-edge flank 62 are helical. The first peripheral-edge flank 61 is a smooth curved surface and is located between the peripheral edge 4 and the second peripheral-edge flank 62. The second peripheral-edge flank 62 undulates periodically in the extending direction of the peripheral edge 4, increasing the heat dissipation area of the milling cutter surface and also facilitating the retention of the coolant, accelerating the cooling speed of the peripheral edge 4 of the milling cutter. When the milling cutter is used to machine materials with small thermal conductivity such as titanium alloy and superalloy, it can accelerate heat dissipation, avoid generating cutting high temperature, contribute to improving the tool durability and extending the tool life. At the same time, due to the provision of the first peripheral-edge flank 61 which is a smooth curved surface, not only the processing difficulty of the peripheral-edge flank 6 is reduced, but also the continuity of the peripheral edge 4 is not damaged, ensuring that the milling cutter of the present invention can also be applied to the finish machining conditions with high requirements for surface machining quality. In addition, since the second peripheral-edge flank 62 undulates periodically in the extending direction of the peripheral edge, a formed grinding wheel can be used for processing, and the processing difficulty is relatively low, reducing the manufacturing cost of the milling cutter.

[0026] In this embodiment, the intersection line 7 between the first peripheral-edge flank 61 and the second peripheral-edge flank 62 is a sine curve on the developed plane of the outer peripheral cylindrical surface 8 of the shank part 2, further reducing the processing difficulty of the second peripheral-edge flank 62.

[0027] In this embodiment, on the developed plane of the outer peripheral cylindrical surface 8 of the shank part 2, the common tangent 9 of all the wave crests on the intersection line 7 between the first peripheral-edge flank 61 and the second peripheral-edge flank 62 is parallel to the peripheral edge 4, and the distance between the two is L. In this way, the continuity of the peripheral edge 4 can be avoided from being damaged, ensuring that the milling cutter of the present invention can also be applied to the finish machining conditions with high requirements for surface machining quality. The value of L needs to be reasonably set, otherwise it will have an adverse effect on the use performance of the milling cutter of the present invention: if the value of L is too small, the strength of the peripheral edge 4 will be reduced, and at the same time, the residual stress generated during the grinding of the second peripheral-edge flank 62 will also have a negative effect on the mechanical state of the peripheral edge 4 during the release process. If the value of L is too large, the rapid heat dissipation effect brought by the second peripheral-edge flank 62 will be weakened. Therefore, if the diameter of the milling cutter is D, it should satisfy: 0.03D ≤ L ≤ 0.08D. In this embodiment, D = 10 mm and L = 0.7 mm.

[0028] In this embodiment, the included angle between the groove line 10 of any wave trough on the second flank 62 of the peripheral edge and the normal direction of the peripheral edge 4 is γ, the helix angle of the spiral chip flute 5 is β, and the opening of the wave trough on the second flank 62 of the peripheral edge should preferably face the shank 2, that is, the groove line 10 deviates from the normal direction of the peripheral edge 4 towards the shank 2 of the milling cutter, so as to avoid the forming grinding wheel interfering with the adjacent peripheral edge 4 when machining the waveform structure on the second flank 62 of the peripheral edge, and it is beneficial for the coolant flowing from the shank 2 to the cutting part 1 to flow more smoothly into the waveform structure on the second flank 62 of the peripheral edge. Therefore, it should satisfy: β ≤ γ ≤ β + 30°. In this embodiment, β = 25° and γ = 30°.

[0029] In this embodiment, the distance d1 between the groove lines 10 of any two adjacent wave troughs on the second flank 62 of the peripheral edge is the same. In order to ensure that the number of waveforms on the fixed length of the peripheral edge 4 can meet the heat dissipation requirements without significantly increasing the machining difficulty and machining time of the second flank 62 of the peripheral edge, it should satisfy: 0.1D ≤ d1 ≤ 0.3D. In this embodiment, d1 = 2 mm.

[0030] In this embodiment, the distance H between the wave crest and the wave trough on the second flank 62 of the peripheral edge in the radial direction of the milling cutter. In order to both increase the heat dissipation area of the second flank 62 of the peripheral edge, be beneficial to accommodating more coolant and enhancing the heat dissipation effect, and not affect the strength of the peripheral edge 4, it should satisfy: 0.01D ≤ H ≤ 0.05D. In this embodiment, H = 0.3 mm.

[0031] In this embodiment, the clearance angle of the first flank 61 of the peripheral edge is α1, and the clearance angle of the second flank 62 of the peripheral edge is α2. It should satisfy: 0 ≤ α1 ≤ 15°, α1 ≤ α2 ≤ 30°. In this embodiment, α1 = 9° and α2 = 20°.

[0032] In the accompanying drawings of the specification, parameters such as γ, β, d1, and H are all marked in the appendix Figure 2 and the A - A and B - B views. Firstly, it is for the convenience of understanding the above parameters. Secondly, the actual values of the above parameters on the milling cutter and the values obtained in the A - A and B - B views in the appendix Figure 2 and the appendix Figure 2 have extremely small errors and can be ignored.

[0033] 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 without departing from the scope of the technical solution of the present invention, or modify it into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of 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 cutter, comprising a cutting part (1) and a shank part (2), wherein at least one bottom edge (3) distributed along the radial direction of the milling cutter and at least one helical peripheral edge (4) extending along the axial direction of the milling cutter are provided on the cutting part (1), the bottom edge (3) is connected to the peripheral edge (4), and the peripheral edge (4) is formed by the intersection of a helical chip flute (5) extending from the cutting part (1) along the axial direction of the milling cutter to the shank part (2) and a peripheral flank (6), and is characterized in that: The peripheral-edge flank (6) includes at least a peripheral-edge first flank (61) and a peripheral-edge second flank (62). Both the peripheral-edge first flank (61) and the peripheral-edge second flank (62) are helical. The peripheral-edge first flank (61) is a smooth curved surface and is located between the peripheral edge (4) and the peripheral-edge second flank (62). The peripheral-edge second flank (62) periodically undulates up and down along the extension direction of the peripheral edge (4). The intersection line (7) between the peripheral-edge first flank (61) and the peripheral-edge second flank (62) is a sine curve on the developed plane of the outer cylindrical surface (8) of the shank (2). On the developed plane of the outer cylindrical surface (8) of the shank (2), the common tangent line (9) of all the wave crests on the intersection line (7) between the peripheral-edge first flank (61) and the peripheral-edge second flank (62) is parallel to the peripheral edge (4), and the distance between the two is L. The diameter of the milling cutter is D, and it should satisfy: 0.03D ≤ L ≤ 0.08D.

2. The milling cutter according to claim 1, characterized in that: The groove line (10) of any wave trough on the peripheral-edge second flank (62) deviates from the normal direction of the peripheral edge (4) towards the shank (2), and the included angle with the normal direction of the peripheral edge (4) is γ. The helix angle of the spiral chip flute (5) is β, and it should satisfy: β ≤ γ ≤ β + 30°.

3. The milling cutter according to claim 1 or 2, characterized in that: The distance d1 between the groove lines (10) of any two adjacent wave troughs on the peripheral-edge second flank (62) is the same, and it should satisfy: 0.1D ≤ d1 ≤ 0.3D.

4. The milling cutter according to claim 1 or 2, characterized in that: The distance H between the wave crest and the wave trough on the peripheral-edge second flank (62) in the radial direction of the milling cutter should satisfy: 0.01D ≤ H ≤ 0.05D.

5. The milling cutter according to claim 1 or 2, characterized in that: The clearance angle of the peripheral-edge first flank (61) is α1, and the clearance angle of the peripheral-edge second flank (62) is α2, and it should satisfy: 0 ≤ α1 ≤ 15°, α1 ≤ α2 ≤ 30°.

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