Cylindrical milling cutter

Abstract

The invention relates to the technical field of cutting machining, in particular to a cylindrical milling cutter which comprises a cylindrical cutter body and cutter teeth distributed on the circumference of the cutter body, the cutter teeth comprise fine working teeth and rough working teeth, the wedge angle of each fine working tooth is smaller than that of each rough working tooth, and the rotation diameter of each fine working tooth is smaller than that of each rough working tooth. The milling cutter comprises the rough working teeth and the fine working teeth at the same time, the rough working teeth enable the milling cutter to have high cutting capacity, large-cutting-amount cutting can be carried out, the high material removal rate can be achieved at a time, and compared with an existing fine tooth milling cutter, the strength of the cutter teeth is higher; by means of the fine teeth, the milling cutter can obtain good surface smoothness in the machining process, the cutting quality is high, and compared with an existing coarse tooth milling cutter, the machining precision is higher; the rotation diameter of the fine working teeth is set to be smaller than that of the coarse working teeth, so that the fine working teeth can be protected by the coarse working teeth, the fine working teeth are prevented from participating in large cutting output, and the condition that tooth tips of the fine working teeth are broken is not easy to occur.

Description

Technical Field

[0001] The invention relates to the technical field of cutting processing, in particular to a cylindrical milling cutter. Background Art

[0002] Cylindrical milling cutter, also known as flat milling roller cutter, is suitable for machining planes on horizontal milling machines. Cylindrical milling cutter includes a cylindrical cutter body and teeth evenly distributed on the circumference of the cutter body. Various mechanical methods often include finishing and roughing, and cylindrical milling cutters are no exception. Roughing is used to remove more part materials, and the roughness of the machined surface is poor; the front and back angles of the teeth of the cylindrical milling cutter for roughing are small, the wedge angle is large, and the tooth strength is high; but the teeth are not sharp enough, and the cutting is not light enough; therefore, it is suitable for roughing with a large amount of cutting. Finishing removes less part material, and the roughness of the machined surface is better. The front and back angles of the teeth of the cylindrical milling cutter for finishing are large, the wedge angle is small, the teeth are sharp, and the cutting is light; but the tooth strength is low, which is suitable for finishing with a small amount of cutting.

[0003] When the material removal rate is high and the precision of the machined surface is required to be high, it is usually necessary to use a roughing milling cutter for rough machining first, and then use a fine machining milling cutter for fine machining to achieve the required machining precision. At least two cuttings are required, and the machining efficiency is low. Therefore, the applicant invented a cylindrical milling cutter that can remove more material in one machining and obtain a machined surface with better roughness.

[0004] After searching, the patent with application number 202311665601.X discloses a high-strength roughing and finishing integrated milling cutter. The cutter head of the milling cutter is provided with two blades for roughing and finishing, and the two blades can be switched. When roughing, the roughing blade is switched to the finishing blade, and when finishing, all roughing blades are switched to the finishing blade. Although the milling cutter can perform both roughing and finishing, roughing and finishing still need to be performed twice. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a cylindrical milling cutter which can remove more materials and obtain a machined surface with better roughness in one machining.

[0006] The technical solution adopted by the present invention is: the 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, the finishing teeth and the roughing teeth are arranged alternately, the wedge angle of the finishing teeth is smaller than the wedge angle of the roughing teeth, and the rotation radius of the finishing teeth is smaller than the rotation radius of the roughing teeth.

[0007] Furthermore, the turning radius of the finishing tooth is R 1 , the turning radius of the rough-machined tooth is R 2, the difference between the rotational radius of the roughing teeth and that of the finishing teeth is K, and K = R 2 - R 1 , and K < 20 μm.

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

[0009] Furthermore: the rake angle of the finishing teeth is α, 10° < α < 20°, 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 = 15°, the rake angle γ of the roughing teeth = 3°; the clearance angle β of the finishing teeth = 9°, and the clearance angle θ of the roughing teeth = 3°.

[0011] Furthermore: the cutter teeth are straight teeth.

[0012] Furthermore: the cutter teeth are helical teeth.

[0013] The beneficial effect of the present invention is as follows: when using the existing roughing milling cutter for machining, the machining amount (the thickness of the removed material) for each cutter tooth in one cutting is F, and the number of cutter teeth is n, then the machining amount for one revolution of the cutter is nF. When using the cylindrical milling cutter of the present invention for machining, with the same cutter advancing speed, the difference between the rotational radius of the roughing teeth and that of the finishing teeth is K. Then as Figure 4 shown, after the roughing teeth finish machining, the finishing teeth start machining. Since the rotational diameter of the finishing teeth is small, the machining amount is F - K; then the roughing teeth machine again, and the machining amount is F + K; then the finishing teeth machine again, and the machining amount is F - K; and so on in a cycle; the machining amount for one revolution of the cutter is still nF.

[0014] The difference is that in the present invention, the roughing teeth and the finishing teeth machine alternately. The roughing teeth have a large wedge angle and high cutter tooth strength, and first remove more materials; then the finishing teeth machine, removing less materials and with a light cutting, which can make the surface of the part have a better roughness. Under the same parameters and machining conditions, the invention combines the large cutting amount of roughing and the high surface quality of finishing. At the same time, since the roughing teeth that bear the large cutting amount have high strength, the tool tip is not easily damaged, while the wedge angle of the finishing teeth is small and the tool tip is sharp, which is more conducive to obtaining an excellent surface quality; and because the cutting amount is small, it also avoids the chipping caused by the tool tip being too sharp. Therefore, under the same milling parameters, the present invention can obtain a high surface quality in one machining, while the traditional machining method requires roughing and finishing in two steps, so it can greatly improve the machining efficiency. Description of the Drawings

[0015] Figure 1Front view of the cylindrical milling cutter of the present invention;

[0016] Figure 2 Stereogram of the cylindrical milling cutter of the present invention;

[0017] Figure 3 Side view of the cylindrical milling cutter of the present invention;

[0018] Figure 4 Usage state diagram of the cylindrical milling cutter of the present invention.

[0019] Reference numerals: 1, cutter body; 2, finish machining teeth; 3, rough machining teeth; 4, workpiece. Detailed implementation manners

[0020] The following combines the appended Figures 1-4 to describe the present invention in detail.

[0021] The cylindrical milling cutter includes a cylindrical cutter body 1 and cutting teeth evenly distributed on the circumference of the cutter body 1. The cutting teeth include finish machining teeth 2 and rough machining teeth 3. The finish machining teeth 2 and the rough machining teeth 3 are arranged alternately. The wedge angle of the finish machining teeth 2 is smaller than the wedge angle of the rough machining teeth 3, and the turning radius of the finish machining teeth 2 is smaller than the turning radius of the rough machining teeth 2.

[0022] It should be understood that the wedge angle refers to the angle between the rake face and the flank face of the cutting tooth. The larger the wedge angle, the blunter the cutting tooth, the larger the contact area between the tool tip and the workpiece, and the greater the frictional resistance between the workpiece 4 and the flank face, resulting in a poorer surface quality. On the contrary, the smaller the wedge angle, the sharper the cutting tooth, the smaller the contact area between the tool tip and the workpiece 4, and the smaller the frictional resistance between the workpiece 4 and the flank face, resulting in a better surface quality.

[0023] That is to say, the rough machining teeth 3 enable the milling cutter to have a high cutting ability and can perform cutting with a large cutting amount. The finish machining teeth 2 enable the milling cutter to obtain a better surface finish and a higher cutting quality during the machining process.

[0024] However, since the wedge angle of the finish machining teeth 2 is small and the tool tip is sharp, the strength of its tool tip is low. Therefore, in order to avoid the situation that the tool tip of the finish machining teeth 2 is damaged due to the low tool tip strength during cutting, the turning diameter of the finish machining teeth 2 is set to be not equal to the turning diameter of the rough machining teeth 3, that is, the turning diameter of the finish machining teeth 2 is smaller than the turning diameter of the rough machining teeth 3. In this way, during milling, the rough machining teeth 3 first remove a large part of the material on the surface of the workpiece 4, and then the finish machining teeth 2 perform cutting after the rough machining teeth 3 have finished cutting. That is to say, when the finish machining teeth 2 perform cutting, it is not necessary to perform cutting to remove a large amount of material, but only to perform cutting on the surface after the rough machining teeth 3 have removed the material. In this way, it is avoided that the finish machining teeth 2 participate in a large cutting amount, and the situation of tool tip fracture caused by insufficient tool tip strength will not occur.

[0025] For the sake of easy understanding, the concept of surface roughness is introduced here. Surface roughness refers to the unevenness of a machined surface with small spacing and minute peaks and valleys. Assuming that the roughness is the protrusion on the surface of the workpiece 4 after machining, the smaller the protrusion height of the protrusion, the smaller the surface roughness, and the smoother the surface. On the contrary, the larger the protrusion height of the protrusion, the larger the surface roughness, and the rougher the surface. Since the cutting amount of the roughing tooth 3 is relatively large and the protrusion height of the protrusion on the surface of the workpiece 4 after machining by the finishing tooth 2 is small, therefore, the roughing tooth 3 and the finishing tooth 2 are assembled on a cutter body 1. Thus, the roughing tooth 3 undertakes the heavy responsibility of large cutting amount, while the finishing tooth 2 performs machining with higher precision. When a higher material removal rate and a higher precision of the machined surface are required, compared with the existing machining method that requires rough machining followed by finishing to achieve the required machining precision, the milling cutter provided by the present invention has 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 larger than that of the roughing tooth 3, the clearance angle of the finishing tooth 2 is less than or equal to that of the roughing tooth 3, and the degree of the smaller clearance angle is lower than the degree of the larger rake angle. 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 alloy, copper alloy, and mild steel, etc., and can also machine materials with higher hardness or stronger cutting force, such as stainless steel, cemented carbide, and cast iron, etc.; 2) The rake angle of the finishing tooth 2 is less than or equal to that of the roughing tooth 3, the clearance angle of the finishing tooth 2 is larger than that of the roughing tooth 3, and the degree of the larger clearance angle is higher than the degree of the smaller rake angle. 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 high hardness, materials that require higher precision and surface quality, and materials with higher requirements for tool durability; 3) The rake angle of the finishing tooth 2 is larger than that of the roughing tooth 3, and the clearance angle of the finishing tooth 2 is larger than that of the roughing tooth 3. The present invention preferably has the rake angle of the finishing tooth 2 larger than that of the roughing tooth 3 and the clearance angle of the finishing tooth 2 larger than that of the roughing tooth 3. This design is suitable for machining materials with higher hardness or requiring high precision and high surface quality, such as stainless steel, titanium alloy, and superalloy, etc.

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

[0028] Furthermore, the turning radius of the finish machining tooth 2 is R1, the turning radius of the rough machining tooth 3 is R2, and the difference between the turning radius of the rough machining tooth 3 and the turning radius of the finish machining tooth 2 is K, where K = R2 - R1 and K < 20 μm.

[0029] It can be understood here that the surface roughness of the rough machining tooth 3 after machining is relatively large. When the rough machining tooth 3 finishes cutting, since the rotational speed of the milling cutter is much higher than the feed speed of the milling cutter on the workpiece surface, the subsequent finish machining tooth 2 will perform a cutting operation on part or all of the surface machined by the rough machining tooth 3 again. After the finish machining tooth 2 performs the cutting, the remaining part is K plus the cutting error of the finish machining tooth 2. And since K is generally less than the lower limit of the error of the rough machining tooth 3 minus the upper limit of the error of the finish machining tooth 2, the surface finish is higher compared to the surface machined by the existing rough tooth milling cutter.

[0030] Since the surface accuracy after cutting by the finish machining tooth 2 is higher than that after cutting by the rough machining tooth 3, and according to the roughness of the workpiece 4 surface machined by the rough tooth milling cutter is usually Ra = 5 - 20 μm, and the roughness of the workpiece 2 surface machined by the fine tooth milling cutter is usually Ra = 0.4 - 3.2 μm. Therefore, in the present invention, it is determined that K < 20 μm, preferably K < 5 μm, and more preferably K < 1.8 μm (i.e., K < (5 - 3.2)).

[0031] For the sake of easy understanding, the following gives an example to illustrate that the alternate arrangement of the finish machining tooth 2 and the rough machining tooth 3, and the turning diameter of the finish machining tooth 2 being smaller than that of the rough machining tooth 3 can improve the machining efficiency:

[0032] As Figure 4 Shown is the usage state diagram of the cylindrical milling cutter of the present invention. Taking the number of cutter teeth as 6 as an example, in the conventional design, when all the cutter teeth of the milling cutter are rough machining teeth 3, the 6 tooth tips of the milling cutter are on the same rotation. Since the milling cutter rotates at a constant speed and moves relative to the workpiece 4 at a constant speed, the cutting amount of each edge is the same. Assuming the cutting thickness of one tooth is F, the total thickness cut by the milling cutter rotating one circle is 6F.

[0033] And in order to achieve the required roughness, it is also necessary to use a finish machining milling cutter to machine the surface of the workpiece 4 again, so two machining operations are required.

[0034] When the milling cutter is arranged such that the finishing teeth 2 and the roughing teeth 3 are alternately arranged, and the total number of teeth is still 6, during milling, with the feed rate and the linear velocity remaining unchanged, when rotating one circle, except at the beginning of cutting, the thickness of the chip cut by the first roughing tooth 3 is F + K, the thickness of the chip cut by the first finishing tooth 2 is F - K, the thickness of the chip cut by the second roughing tooth 3 is F + K, the thickness of the chip cut by the second finishing tooth 2 is F - K, the thickness of the chip cut by the third roughing tooth 3 is F + K, and the thickness of the chip cut by the third finishing tooth 2 is F - K. Then, the total thickness of the chips cut when the milling cutter rotates one circle is 6F. It should be noted that since the finishing tooth 2 further mills the surface after the roughing tooth 3 has processed it, therefore, after the roughing tooth 3 mills, there needs to be a margin for the finishing tooth 3 to further mill in order to improve the machining accuracy. Therefore, when using the cylindrical milling cutter of the present invention for machining, it is generally required that the cutting thickness F > K.

Claims

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

2. The cylindrical milling cutter according to claim 1, characterized in that The turning radius of the fine-machined tooth (2) is R1, the turning radius of the rough-machined tooth (3) is R2, and the difference between the turning radius of the rough-machined tooth (3) and the turning radius of the fine-machined tooth (2) is K, K=R2-R1, K<20μm.

3. The cylindrical milling cutter according to claim 2, characterized in that: The front angle of the finishing tooth (2) is greater than the front angle of the roughing tooth (3), and the back angle of the finishing tooth (2) is greater than the back angle of the roughing tooth (3).

4. The cylindrical milling cutter according to claim 3, characterized in that The front angle of the fine processing tooth (2) is α, 10°<α<20°, and the front angle of the rough processing tooth (3) is γ, 1°<γ<5°; the back angle of the fine processing tooth (2) is β, 5°<β<10°, and the back angle of the rough processing tooth (3) is θ, 1°<θ<5°.

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

6. The cylindrical milling cutter according to claim 5, characterized in that The teeth are straight.

7. The cylindrical milling cutter according to claim 5, characterized in that The teeth are spiral.

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