Cylindrical milling cutter

Abstract

The utility model relates to the technical field of cutting machining, in particular to a cylindrical milling cutter which comprises a cylindrical cutter body and cutter teeth uniformly distributed on the circumference of the cutter body, the cutter teeth comprise finish machining teeth and rough machining teeth, the finish machining teeth and the rough machining teeth are alternately arranged, and the wedge angle of each finish machining tooth is smaller than that of each rough machining tooth. The turning radius of the finish machining teeth is smaller than that of the rough machining teeth. The rough machining teeth and the finish machining teeth are alternately used for machining, the rough machining teeth are large in wedge angle, the strength of the cutter teeth is high, and more materials are firstly removed; and machining is carried out after finish machining, few materials are removed, cutting is light and fast, and the surface of the part can have better roughness. Under the same parameters and machining conditions, the large cutting output of rough machining and the high surface quality of finish machining are achieved.

Description

Technical Field

[0001] This utility model relates to the field of cutting and machining technology, and in particular to a cylindrical milling cutter. Background Technology

[0002] Cylindrical end mills, also known as face milling cutters, are suitable for machining flat surfaces on horizontal milling machines. A cylindrical end mill consists of a cylindrical cutter body and teeth evenly distributed around its circumference. Like many machining processes, roughing and finishing are performed using cylindrical end mills. Roughing removes a significant amount of material, resulting in a less smooth surface. Cylindrical end mills used for roughing have smaller rake and clearance angles and larger wedge angles, resulting in high tooth strength; however, the teeth are not sharp enough, leading to less agile cutting. Therefore, they are suitable for roughing with larger cutting depths. Finishing removes less material, resulting in a better surface roughness. Cylindrical end mills used for finishing have larger rake and clearance angles and smaller wedge angles, resulting in sharper teeth and agile cutting; however, the tooth strength is lower, making them suitable for finishing with smaller cutting depths.

[0003] When a high material removal rate is required and a high precision of the machined surface is demanded, it is usually necessary to first use a roughing milling cutter for roughing and then a finishing milling cutter for finishing to achieve the required machining accuracy. This requires at least two cuts, resulting in low machining efficiency. Therefore, the applicant proposes a cylindrical milling cutter that can remove more material in a single machining operation and obtain a machined surface with good roughness.

[0004] A search revealed a patent with application number 202311665601.X, which discloses a high-strength integrated roughing and finishing milling cutter. This cutter has two types of inserts on its cutter head, one for roughing and one for finishing, and these inserts are switchable. For roughing, the cutter switches to the roughing insert, and for finishing, all roughing inserts are switched to the finishing insert. Although this milling cutter can perform both roughing and finishing, the two processes still need to be performed separately. Utility Model Content

[0005] The technical problem to be solved by this utility model is to provide a cylindrical end mill that can remove more material and obtain a machined surface with better roughness in one operation.

[0006] The technical solution adopted in this utility model is as follows: a cylindrical milling cutter includes a cylindrical cutter body and cutter teeth evenly distributed on the circumference of the cutter body. The cutter teeth include finishing teeth and roughing teeth, which are alternately arranged. The wedge angle of the finishing teeth is smaller than that of the roughing teeth, and the rotation radius of the finishing teeth is smaller than that of the roughing teeth.

[0007] Furthermore, the radius of rotation of the finishing tooth is R1, the radius of rotation of the roughing tooth is R2, and the difference between the radius of rotation of the roughing tooth and the radius of rotation of the finishing tooth is K, where K = R2 - R1 and K < 20 μm.

[0008] Furthermore, the rake angle of the finishing tooth is greater than that of the roughing tooth, and the clearance angle of the finishing tooth is greater than that of the roughing tooth.

[0009] Furthermore, the rake angle of the finishing teeth is α, 10° < α < 20°, and the rake angle of the roughing teeth is γ, 1° < γ < 5°; the clearance angle of the finishing teeth is β, 5° < β < 10°, and the clearance angle of the roughing teeth is θ, 1° < θ < 5°.

[0010] Furthermore, the rake angle α of the finishing teeth is 15°, and the rake angle γ of the roughing teeth is 3°; the clearance angle β of the finishing teeth is 9°, and the clearance angle θ of the roughing teeth is 3°.

[0011] Furthermore, the cutting teeth are straight.

[0012] Furthermore, the cutting teeth are helical.

[0013] The beneficial effects of this utility model are as follows: Assuming that the machining amount (thickness of material removed) per tooth in a single pass of a conventional roughing milling cutter is F, and the number of teeth is n, then the machining amount per revolution of the cutter is nF. Using the cylindrical milling cutter of this utility model, with the same cutter feed speed, the difference between the radius of rotation of the roughing teeth and the radius of rotation of the finishing teeth is K. Then, as... Figure 4 As shown, after roughing the teeth, finishing the teeth are machined. Due to the small rotation diameter of the finishing teeth, the machining amount is FK. Then, roughing the teeth is machined, and the machining amount is F+K. Then, finishing the teeth are machined, and the machining amount is FK. This cycle continues. The machining amount for one revolution of the tool is still nF.

[0014] Unlike traditional milling methods, this invention alternates between roughing and finishing teeth. The roughing teeth have a large wedge angle and high strength, removing a significant amount of material initially. Finishing follows, removing less material and cutting more quickly, resulting in a better surface finish. Under the same parameters and processing conditions, this invention combines the large cutting volume of roughing with the high surface quality of finishing. Furthermore, the high strength of the roughing teeth, which bear the large cutting volume, reduces the risk of tool tip damage, while the small wedge angle and sharp tip of the finishing teeth contribute to excellent surface quality. The smaller cutting volume also avoids chipping caused by an overly sharp tool tip. Therefore, under the same milling parameters, this invention achieves a high surface quality in a single machining operation, whereas traditional methods require two separate roughing and finishing processes, thus significantly improving processing efficiency. Attached Figure Description

[0015] Figure 1 This is a front view of the cylindrical milling cutter of this utility model;

[0016] Figure 2 This is a perspective view of the cylindrical end mill of this utility model;

[0017] Figure 3 This is a side view of the cylindrical milling cutter of this utility model;

[0018] Figure 4 This is a diagram showing the usage state of the cylindrical milling cutter of this utility model.

[0019] Reference numerals: 1. Tool body, 2. Finishing teeth, 3. Roughing teeth, 4. Workpiece. Detailed Implementation

[0020] The following is in conjunction with the appendix Figure 1-4 This utility model will be described in detail.

[0021] The cylindrical end mill includes a cylindrical cutter body 1 and cutter teeth evenly distributed on the circumference of the cutter body 1. The cutter teeth include finishing teeth 2 and roughing teeth 3, which are alternately arranged. The wedge angle of the finishing teeth 2 is smaller than that of the roughing teeth 3, and the turning radius of the finishing teeth 2 is smaller than that of the roughing teeth 3.

[0022] It is important to understand that the wedge angle refers to the angle between the rake face and the flank face of the cutting edge. The larger the wedge angle, the blunter the cutting edge, the larger the contact area between the cutting edge and the workpiece, and the greater the frictional resistance between the workpiece and the flank face, resulting in a poorer surface quality. Conversely, the smaller the wedge angle, the sharper the cutting edge, the smaller the contact area between the cutting edge and the workpiece, and the smaller the frictional resistance between the workpiece and the flank face, resulting in a better surface quality.

[0023] In other words, the roughing tooth 3 gives the milling cutter a high cutting capability, enabling it to perform large-volume cutting, while the finishing tooth 2 allows the milling cutter to achieve a better surface finish and higher cutting quality during the machining process.

[0024] However, because the wedge angle of the finishing tooth 2 is small and the tip is sharp, its tip strength is low. Therefore, in order to avoid the finishing tooth 2 from breaking during cutting due to its low tip strength, the rotation diameter of the finishing tooth 2 is set to be different from that of the roughing tooth 3. That is, the rotation diameter of the finishing tooth 2 is smaller than that of the roughing tooth 3. In this way, during milling, the roughing tooth 3 removes a large portion of the material from the surface of the workpiece 4 first, and then the finishing tooth 2 cuts only after the roughing tooth 3 has finished cutting. In other words, when the finishing tooth 2 cuts, it does not need to remove a large amount of material, but only needs to cut the surface removed by the roughing tooth 3. This avoids the finishing tooth 2 participating in a large amount of cutting, and thus prevents the tip from breaking due to insufficient tip strength.

[0025] For ease of understanding, the concept of surface roughness is introduced here. Surface roughness refers to the unevenness of a machined surface, characterized by small gaps and minute peaks and valleys. Assuming roughness is represented by the protrusions on the surface of the workpiece 4 after machining, the smaller the protrusion height, the smaller the surface roughness, and the smoother the surface; conversely, the larger the protrusion height, the larger the surface roughness, and the rougher the surface. Since the roughing tooth 3 has a large cutting volume, and the finishing tooth 2 results in a smaller protrusion height on the surface of the workpiece 4, the roughing tooth 3 and the finishing tooth 2 are combined onto a single cutter body 1. Thus, the roughing tooth 3 bears the heavy responsibility of large cutting volume, while the finishing tooth 2 performs high-precision machining. When a high material removal rate and high surface precision are required, compared to existing machining methods that require roughing followed by finishing to achieve the desired machining accuracy, the milling cutter provided by this invention offers higher machining efficiency.

[0026] The wedge angle of the finishing tooth 2 is smaller than that of the roughing tooth 3, including the following situations: 1) The rake angle of the finishing tooth 2 is greater than that of the roughing tooth 3, and the clearance angle of the finishing tooth 2 is less than or equal to that of the roughing tooth 3, and the degree to which the clearance angles are smaller is less than the degree to which the rake angles are larger. For example, the rake angle of the finishing tooth 2 is 15°, and the rake angle of the roughing tooth 3 is 3°; the clearance angle of the finishing tooth 2 is 9°, and the clearance angle of the roughing tooth 3 is 10°. This design is suitable for machining relatively soft materials that require a certain cutting efficiency and surface finish, such as aluminum alloys, copper alloys, and mild steel, as well as materials with higher hardness or requiring stronger cutting forces, such as stainless steel, cemented carbide, and cast iron; 2) The rake angle of the finishing tooth 2 is less than or equal to that of the roughing tooth 3, and the clearance angle of the finishing tooth 2 is greater than that of the roughing tooth 3, and the degree to which the clearance angles are larger is greater than the degree to which the rake angles are smaller. For example, the rake angle of the finishing tooth 2 is 15°, and the rake angle of the roughing tooth 3 is 20°; the clearance angle of the finishing tooth 2 is 9°, and the clearance angle of the roughing tooth 3 is 3°. This design is suitable for machining materials with medium to hard hardness, materials requiring high precision and surface quality, and materials with high requirements for tool durability; 3) The rake angle of the finishing tooth 2 is greater than the rake angle of the roughing tooth 3, and the clearance angle of the finishing tooth 2 is greater than the clearance angle of the roughing tooth 3. Preferably, the rake angle of the finishing tooth 2 is greater than the rake angle of the roughing tooth 3, and the clearance angle of the finishing tooth 2 is greater than the clearance angle of the roughing tooth 3. This design is suitable for machining materials with high hardness, such as stainless steel, titanium alloys, and high-temperature alloys, or materials requiring high precision and high surface quality.

[0027] In this invention, the rake angle of the finishing tooth 2 is preferably α, where 10° < α < 20°, and more preferably α = 15°; the rake angle of the roughing tooth 3 is γ, where 1° < γ < 5°, and more preferably γ = 3°; the clearance angle of the finishing tooth 2 is β, where 5° < β < 10°, and more preferably β = 9°; and the clearance angle of the roughing tooth 3 is θ, where 1° < θ < 5°, and more preferably θ = 3°. The specific structure is as follows: Figure 1 As shown.

[0028] Furthermore, the radius of rotation of the finishing tooth 2 is R1, the radius of rotation of the roughing tooth 3 is R2, and the difference between the radius of rotation of the roughing tooth 3 and the radius of rotation of the finishing tooth 2 is K, K = R2 - R1, K < 20 μm.

[0029] This can be understood as follows: the surface roughness after roughing tooth 3 is relatively large. After roughing tooth 3 completes cutting, since the milling cutter's rotation speed is much higher than the milling cutter's feed speed on the workpiece surface, the subsequent finishing tooth 2 will cut part or even all of the surface after roughing tooth 3. After finishing tooth 2 cuts, the remaining part is K plus the cutting error of finishing tooth 2. Since K is generally less than the lower limit of the error of roughing tooth 3 minus the upper limit of the error of finishing tooth 2, the surface finish is higher than that of the surface processed by the existing coarse tooth milling cutter.

[0030] Since the surface finish after finishing the tooth 2 is higher than that after roughing the tooth 3, and the surface roughness of the workpiece 4 after machining with a coarse tooth milling cutter is usually Ra = 5 to 20 μm, while the surface roughness of the workpiece 2 after machining with a fine tooth milling cutter is usually Ra = 0.4 to 3.2 μm, in this invention, K is determined to be < 20 μm, preferably K < 5 μm, and more preferably K < 1.8 μm (i.e., K < (5-3.2)).

[0031] To facilitate understanding, the following example illustrates how alternating arrangements of finishing teeth 2 and roughing teeth 3, with the rotation diameter of finishing teeth 2 being smaller than that of roughing teeth 3, can improve machining efficiency:

[0032] like Figure 4 The diagram shows the usage state of the cylindrical milling cutter of this utility model. Taking a cutter with 6 teeth as an example, in a conventional design, when all the teeth of the milling cutter are roughing teeth 3, all 6 tooth tips of the milling cutter are on the same rotation. Since the milling cutter rotates at a constant speed and moves at a constant speed relative to the workpiece 4, the cutting amount of each cutting edge is the same. Assuming the cutting thickness of one tooth is F, the total thickness cut by the milling cutter in one rotation is 6F.

[0033] To achieve the required surface roughness, the workpiece surface 4 needs to be machined again with a finishing milling cutter, which requires two machining operations.

[0034] When the milling cutter is set to alternate between finishing teeth 2 and roughing teeth 3, the total number of teeth remains 6. Therefore, during milling, with the feed rate and linear velocity unchanged, after one revolution, the thickness of the chips cut by the first roughing tooth 3 is F+K, the thickness of the chips cut by the first finishing tooth 2 is FK, the thickness of the chips cut by the second roughing tooth 3 is F+K, the thickness of the chips cut by the second finishing tooth 2 is FK, the thickness of the chips cut by the third roughing tooth 3 is F+K, and the thickness of the chips cut by the third finishing tooth 2 is FK. Thus, the total thickness of the chips cut by the milling cutter in one revolution is 6F. It should be noted that since the finishing teeth 2 further mill the surface after the roughing teeth 3 have been machined, there needs to be a margin after the roughing teeth 3 are milled for the finishing teeth 3 to improve machining accuracy. Therefore, when using the cylindrical milling cutter of this invention, the cutting thickness F > K is generally required.

Claims

1. A cylindrical end mill, comprising a cylindrical cutter body (1) and cutter teeth evenly distributed on the circumference of the cutter body (1), characterized in that: The cutting teeth include finishing teeth (2) and roughing teeth (3), which are alternately arranged. The wedge angle of the finishing teeth (2) is smaller than that of the roughing teeth (3), and the radius of rotation of the finishing teeth (2) is smaller than that of the roughing teeth (3).

2. The cylindrical end mill according to claim 1, characterized in that, The radius of rotation of the finishing tooth (2) is R1, the radius of rotation of the roughing tooth (3) is R2, and the difference between the radius of rotation of the roughing tooth (3) and the radius of rotation of the finishing tooth (2) is K, K = R2 - R1, K < 20 μm.

3. The cylindrical end mill according to claim 2, characterized in that, The rake angle of the finishing tooth (2) is greater than that of the roughing tooth (3), and the clearance angle of the finishing tooth (2) is greater than that of the roughing tooth (3).

4. The cylindrical end mill according to claim 3, characterized in that, The rake angle of the finishing tooth (2) is α, 10° < α < 20°, and the rake angle of the roughing tooth (3) is γ, 1° < γ < 5°; the clearance angle of the finishing tooth (2) is β, 5° < β < 10°, and the clearance angle of the roughing tooth (3) is θ, 1° < θ < 5°.

5. The cylindrical end mill according to claim 4, characterized in that, The rake angle α of the finishing tooth (2) is 15°, and the rake angle γ of the roughing tooth (3) is 3°; the clearance angle β of the finishing tooth (2) is 9°, and the clearance angle θ of the roughing tooth (3) is 3°.

6. The cylindrical end mill according to claim 5, characterized in that, The cutting teeth are straight.

7. The cylindrical end mill according to claim 5, characterized in that, The blade teeth are helical.

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