Blade root milling cutter and preparation method thereof

Abstract

The invention relates to a blade root milling cutter and a preparation method thereof.The blade root milling cutter comprises a center cylinder and forming blades arranged on the outer wall of the center cylinder, each forming blade comprises a plurality of blade sections, and the blade sections are circumferentially and evenly distributed around the center cylinder and are sequentially arranged in the axial direction of the center cylinder; in every two adjacent blade sections, the opposite end faces of the two blade sections are located in the same plane, and the plane is perpendicular to the central cylinder. The forming cutting edge which is originally used as a whole is divided into a plurality of cutting edge sections, the different cutting edge sections are located in different directions of the central cylinder, and when one cutting edge section makes contact with the blade root and mills the blade root, the other cutting edge sections do not make contact with the blade root, so that the contact length of the forming cutting edge and the blade root is reduced, and the blade root milling efficiency is improved. The cutting output of each blade section is reduced, so that the cutting resistance can be reduced, the milling cutter is prevented from bending and greatly vibrating, and the machining precision is favorably improved.

Description

Technical Field

[0001] The invention belongs to the field of milling cutters, in particular to a blade root milling cutter and a preparation method thereof. Background Art

[0002] Blades are important parts of equipment such as steam turbines and aircraft engines. When preparing blades, milling is usually used. The root of the blade is used to install the blade on the turbine or aircraft engine. A common root structure is a fir-tree-shaped root. When processing the fir-tree-shaped root, a special forming milling cutter is generally used for rough milling and fine milling. Two milling processes can process the fir-tree-shaped root to the designed size. For details, please refer to the invention patent with application number CN201210538134.X - a rough milling method for fir-tree-shaped root. The existing root milling cutter includes a central column, and the surface of the central column is provided with a plurality of forming blades evenly distributed around the central column. The shape of the forming blade is adapted to the shape of the root. Please refer to the utility model patent with application number CN200920306966.2 - a longitudinal root milling cutter with TiN coating.

[0003] When milling with existing blade root milling cutters, Figure 1 and Figure 2 As shown, the milling cutter Figure 2 The left side of the blade is fed to the right side, and the milling cutter rotates at high speed, so that each forming blade cuts the side of the blade root. Since the blade root forming surface has a certain height, the contact length a between the forming blade and the blade root forming surface is large, so the cutting resistance is large, which easily causes the milling cutter to bend and vibrate. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a blade root milling cutter which can reduce cutting resistance, prevent the milling cutter from bending, and reduce the vibration of the milling cutter. A preparation method is also provided for preparing the blade root milling cutter.

[0005] In order to solve the above problems, the technical solution adopted by the present invention is: a blade root milling cutter comprises a central cylinder and a forming blade arranged on the outer wall of the central cylinder,

[0006] Each of the forming blades comprises a plurality of blade segments, the plurality of blade segments are evenly distributed in a circular shape around the central cylinder, and the plurality of blade segments are sequentially arranged along the axial direction of the central cylinder;

[0007] In two adjacent blade segments, the end surfaces of the two blade segments facing each other are located in the same plane, and the plane is perpendicular to the central column.

[0008] Furthermore, the blade segment includes a first blade segment, a second blade segment and a third blade segment.

[0009] Furthermore, there are two of each of the first blade segment, the second blade segment and the third blade segment, and the two first blade segments are centrally symmetrical with respect to the center line of the central column, the two second blade segments are centrally symmetrical with respect to the center line of the central column, and the two third blade segments are centrally symmetrical with respect to the center line of the central column.

[0010] Further, the two first blade segments are connected as a whole through a first connecting column, the two second blade segments are connected as a whole through a second connecting column, and the two third blade segments are connected as a whole through a third connecting column;

[0011] The central column is provided with a first positioning groove, a second positioning groove and a third positioning groove which radially penetrate the central column. The first connecting column, the second connecting column and the third connecting column are respectively located in the first positioning groove, the second positioning groove and the third positioning groove, and the first connecting column, the second connecting column and the third connecting column are connected to the central column through a connecting piece.

[0012] Furthermore, the first blade segment, the second blade segment and the third blade segment are arranged in sequence from the milling end to the clamping end, and the connecting part includes a connecting screw and a positioning pin. The first connecting column is connected to the central column by two screws, a threaded hole is arranged at the center of the first connecting column, and pin holes are arranged at the centers of the second connecting column and the third connecting column. The pin hole is coaxial with the threaded hole, and the pin hole is connected to the threaded hole, and the positioning pin is interference fit with the pin hole; a locking screw is arranged in the threaded hole, and the locking screw tightens the end of the positioning pin.

[0013] The method for preparing the blade root milling cutter comprises:

[0014] Using carbide rods as raw materials, a central column and multiple blade segments are machined;

[0015] Heat treatment of the central cylinder and blade segments;

[0016] A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially arranged on the surface of the blade segment.

[0017] Furthermore, the transition coating is a CrN layer with a thickness of 1-2 μm. ； The wear-resistant coating is a TiAlN layer with a thickness of 3-5μm ； The anti-friction coating is a MoS2 layer with a thickness of 0.5-1 μm.

[0018] The method for preparing the blade root milling cutter comprises:

[0019] The central cylinder is obtained by machining the carbide rod as the raw material;

[0020] Using carbide rods as raw materials, multiple blade segments are obtained by machining;

[0021] Heat treatment of the central cylinder and blade segments;

[0022] A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially provided on the surface of the blade segment;

[0023] Install the blade segments onto the center column.

[0024] Furthermore, the process of machining a plurality of blade segments using a cemented carbide rod as a raw material is as follows:

[0025] The rod is turned to obtain a first blade segment, a second blade segment and a third blade segment on the surface of the rod, and a cutting allowance is set at the connection between the first blade segment, the second blade segment and the third blade segment to obtain a formed blank;

[0026] The formed blank is milled to obtain planes symmetrical with respect to the center line on both sides of the center line of the bar;

[0027] Cutting the formed blank radially at the cutting margin to obtain a first blade segment, a second blade segment and a third blade segment;

[0028] The cutting surfaces of the first blade segment, the second blade segment and the third blade segment are milled to the designed size.

[0029] The beneficial effects of the present invention are as follows: the present invention divides the original integral forming blade into a plurality of blade segments, and different blade segments are located at different positions of the central column. When one blade segment contacts the blade root and mills the blade root, the remaining blade segments do not contact the blade root, thereby reducing the contact length between the forming blade and the blade root, and reducing the cutting amount of each blade segment, thereby reducing the cutting resistance, preventing the milling cutter from bending and vibrating greatly, and facilitating improving the processing accuracy. At the same time, since each blade segment can form a complete forming blade, the forming requirements can be met. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the main view of the existing milling cutter during milling;

[0031] Figure 2 yes Figure 1 Schematic diagram of the middle A direction;

[0032] Figure 3 is a schematic top view of a blade root milling cutter of the present invention;

[0033] Figure 4 yes Figure 3 A schematic cross-sectional view of the middle BB;

[0034] Figure 5 yes Figure 3 Schematic cross-sectional view of CC;

[0035] Figure 6 yes Figure 3 Schematic cross-sectional view of the middle DD;

[0036] Figure 7 It is a schematic diagram of the milling cutter of the present invention during milling;

[0037] Figure 8 is a schematic cross-sectional view of a tool bar of the present invention;

[0038] Fig. 9 is a schematic diagram of a molded blank obtained by turning in Example 2;

[0039] Fig.10 is a schematic side view of the molded blank after the plane is milled in the second embodiment;

[0040] Fig.11 is a schematic diagram of the first blade segment obtained by cutting;

[0041] Fig.12 is a schematic diagram of the second blade segment obtained by cutting;

[0042] Fig.13 is a schematic diagram of the third blade segment obtained by cutting;

[0043] Figure markings: 1—central column; 2—blade segment; 21—first blade segment; 22—second blade segment; 23—third blade segment; 24—cutting allowance; 3—first connecting column; 4—second connecting column; 5—third connecting column; 6—connecting screw; 7—locating pin; 8—locking screw; 10—blade rod; 13—shock-absorbing cavity; 15—locating sleeve; 16—first piezoelectric material layer; 17—insulating mounting groove; 18—Pettel effect sheet; 19—rectifier; 110—sliding sleeve; 111—pressing block; 112—top plate; 113—second piezoelectric material layer; 114—flexible sleeve; 115—rigid block. DETAILED DESCRIPTION

[0044] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0045] The blade root milling cutter of the present invention is as follows: Figures 3 to 8 As shown, it includes a tool bar 10 and a tool head. The tool bar 10 is used to connect the milling cutter as a whole to the machine tool, and the tool head is used to perform shaping processing on the blade root. Figures 3 to 6As shown, it includes a central cylinder 1 and a shaped blade arranged on the outer wall of the central cylinder 1, and the central cylinder 1 is a cylinder. Each shaped blade includes a plurality of blade segments 2, and the plurality of blade segments 2 constituting a complete shaped blade are evenly distributed in a circle around the central cylinder 1, that is, the plurality of blade segments 2 are at different positions of the central cylinder 1, and when one blade segment 2 contacts the blade root, the remaining blade segments 2 cannot contact the blade root, and when the blade segments 2 rotate with the central cylinder 1, each blade segment 2 can contact the blade root in turn and perform milling processing on the blade root.

[0046] The multiple blade segments 2 constituting a complete formed blade are arranged in sequence along the axial direction of the central column 1, and the end faces of the two adjacent blade segments 2 are located in the same plane, and the plane is perpendicular to the central column 1. The outer dimensions of each blade segment 2 are different. One blade segment 2 remains in the same position. With the center of the central column 1 as the rotation center, the other blade segments 2 are rotated by a certain angle so that the other blade segments 2 are in the same position as the blade segment 2 that remains in the same position in the central column 1. Then, the blade segments 2 can be spliced ​​end to end, thereby obtaining a complete formed blade, the outer shape of which is adapted to the side shape of the longitudinal tree-shaped blade root. During processing, each blade segment 2 rotates with the central column 1 to process a section of the side of the longitudinal tree-shaped blade root respectively. All blade segments 2 cooperate to meet the processing requirements.

[0047] The milling cutter of the present invention processes the longitudinal tree-shaped blade root in the same manner as the prior art, referring to Figure 2 and Figure 7 The milling cutter starts from one end of the longitudinal tree-shaped blade root (such as Figure 2 left end) towards the other end (such as Figure 2 The right end of the middle) is fed to cut the side of the longitudinal tree-shaped blade root to obtain the required shape. Multiple forming milling processes, such as twice, can be used to ensure processing accuracy.

[0048] In the present invention, the forming blade originally as a whole is divided into a plurality of blade segments 2, and different blade segments 2 are located at different positions of the central column 1. When one of the blade segments 2 contacts the blade root and mills the blade root, the remaining blade segments 2 do not contact the blade root, thereby reducing the length a of the forming blade in contact with the blade root, and reducing the cutting amount of each blade segment 2, thereby reducing the cutting resistance, preventing the milling cutter from bending and vibrating greatly, and helping to improve the processing accuracy. At the same time, since each blade segment 2 can form a complete forming blade, the forming requirements can be met. Since the cutting resistance is reduced, the cutting amount of each blade segment 2 is reduced. In order to ensure the processing efficiency, the milling cutter rotation speed can be appropriately increased, thereby increasing the cutting frequency of each blade segment 2.

[0049] There may be one or two forming blades, and each forming blade is divided into a plurality of blade segments 2.

[0050] In the present invention, the blade segments 2 can be 2, 3 or 4, etc., which are determined according to the height of the longitudinal tree-shaped blade root molding surface. As a preferred embodiment, the blade segments 2 include a first blade segment 21, a second blade segment 22 and a third blade segment 23.

[0051] The forming blade can be one or two in total, and each forming blade is divided into a plurality of blade segments 2. Specifically, the first blade segment 21, the second blade segment 22, and the third blade segment 23 are each provided in two, and the two first blade segments 21 are centrally symmetrical with respect to the center line of the central column 1, the two second blade segments 22 are centrally symmetrical with respect to the center line of the central column 1, and the two third blade segments 23 are centrally symmetrical with respect to the center line of the central column 1. The two first blade segments 21, the two second blade segments 22, and the two third blade segments 23 are all symmetrically provided, and the center of gravity of the two first blade segments 21, the two second blade segments 22, and the two third blade segments 23 can be located at the center of the central column 1, thereby improving the stability of the milling cutter during processing.

[0052] The first blade segment 21, the second blade segment 22 and the third blade segment 23 can be integrally formed with the central column 1, that is, a rod is used as a raw material, and the milling cutter of the present invention is obtained by processing the rod. This preparation method can save raw materials and reduce material costs, but due to the strong irregularity of the milling cutter structure of the present invention, the processing difficulty is high, and the position accuracy of each blade segment 2 is difficult to ensure.

[0053] Therefore, the present invention adopts a method of processing the central column 1 and each blade segment 2 separately and then assembling them. Specifically, the two first blade segments 21 are connected as a whole through the first connecting column 3, the two second blade segments 22 are connected as a whole through the second connecting column 4, and the two third blade segments 23 are connected as a whole through the third connecting column 5. The two first blade segments 21 are integrally formed with the first connecting column 3, the two second blade segments 22 are integrally formed with the second connecting column 4, and the two third blade segments 23 are integrally formed with the third connecting column 5. Therefore, the first blade segment 21, the second blade segment 22 and the third blade segment 23 can be obtained by machining, and each component is in a plate shape as a whole, the machining difficulty is low, and the machining accuracy is guaranteed.

[0054] The central column 1 is provided with a first positioning groove, a second positioning groove and a third positioning groove which radially penetrate the central column 1, and the first connecting column 3, the second connecting column 4 and the third connecting column 5 are respectively located in the first positioning groove, the second positioning groove and the third positioning groove, and the first connecting column 3, the second connecting column 4 and the third connecting column 5 are connected to the central column 1 through a connecting piece. The cross-section of the first positioning groove, the second positioning groove and the third positioning groove is rectangular, and is a regular shape groove, so the processing difficulty is low and the processing accuracy is guaranteed.

[0055] During assembly, the first connecting column 3, the second connecting column 4 and the third connecting column 5 are respectively inserted into the first positioning groove, the second positioning groove and the third positioning groove, and the first blade segment 21, the second blade segment 22 and the third blade segment 23 are respectively located outside the first positioning groove, the second positioning groove and the third positioning groove. At this time, the adjacent side surfaces of the first connecting column 3, the second connecting column 4 and the third connecting column 5 fit each other. Then, the first connecting column 3, the second connecting column 4 and the third connecting column 5 are positioned by the connecting piece to ensure the position accuracy and stability of the first blade segment 21, the second blade segment 22 and the third blade segment 23.

[0056] The connecting part includes a connecting screw 6 and a positioning pin 7. The first connecting column 3 is connected to the central column 1 by two screws 6. A threaded hole is arranged at the center of the first connecting column 3. Pin holes are arranged at the centers of the second connecting column 4 and the third connecting column 5. The pin hole is coaxial with the threaded hole, and the pin hole is connected to the threaded hole. The positioning pin 7 has an interference fit with the pin hole. A locking screw 8 is arranged in the threaded hole, and the locking screw 8 tightens the end of the positioning pin 7.

[0057] In order to ensure the stability of the connection, the first blade segment 21, the second blade segment 22 and the third blade segment 23 are arranged in sequence from the milling end to the clamping end, the milling end is the tip of the cutter head, and the clamping end is the handle end. Figure 7 When using the processing method shown, the end face of the first blade segment 21 away from the second blade segment 22 should be flush with the end face of the center column 1 to meet the processing requirements. At this time, the first positioning groove is located on the end face of the center column 1. Therefore, two connecting screws 6 are used to fix the first connecting column 3 to the end of the center column 1, which can prevent the first connecting column 3 from axial and radial movement, thereby ensuring the stability of the first blade segment 21.

[0058] In order to ensure the stability of the second connecting column 4 and the third connecting column 5, the positioning pin 7 is interference fit with the pin holes of the second connecting column 4 and the third connecting column 5, the pin holes can be truncated cone-shaped holes, and the positioning pin 7 can be a truncated cone-shaped pin. In addition, the side wall of the third positioning groove away from the second positioning groove can also be provided with a pin hole, and the positioning pin 7 passes through the pin holes of the second connecting column 4 and the third connecting column 5 and then is inserted into the pin hole of the side wall of the second positioning groove. In order to prevent the positioning pin 7 from loosening, the present invention also uses a locking screw 8 to tighten the positioning pin 7.

[0059] The tool bar 10 can adopt various existing tool bar structures. In order to reduce the vibration during milling, the present invention sets a shock-absorbing structure inside the tool bar 10 of the milling cutter. Specifically, Figure 8 As shown, a shock absorbing cavity 13 is provided inside the cutter bar 10, and the central column 1 extends into the shock absorbing cavity 13, and the central column 1 is coaxial with the cutter bar 10, and the central column 1 can be connected to the cutter bar 10 by screws.

[0060] A positioning sleeve 15 is fixedly arranged in the shock absorbing cavity 13, the central column 1 is located inside the positioning sleeve 15, the positioning sleeve 15 is coaxial with the central column 1, and a first piezoelectric material layer 16 is arranged between the central column 1 and the positioning sleeve 15, and the central column 1 contacts the first piezoelectric material layer 16. The first piezoelectric material layer 16 generates voltage after being squeezed, thereby converting the kinetic energy of vibration into electrical energy.

[0061] The side wall of the damping cavity 13 is provided with a plurality of strip holes, each of which is provided with an insulating mounting groove 17, which can be a plastic groove, and each of which is provided with a Peltier effect sheet 18, which includes a plurality of P-type semiconductors and a plurality of N-type semiconductors, which are alternately arranged. When direct current is supplied to the Peltier effect sheet 18, one end of the Peltier effect sheet 18 can absorb heat from the outside, and the other end can release heat to the outside, thereby realizing heat transfer. The first piezoelectric material layer 16 is connected to a rectifier 19 through a wire, and the rectifier 19 is connected to the Peltier effect sheet 18 through a wire, and the heat absorbing end of the Peltier effect sheet 18 faces the inside of the damping cavity 13, and the heat releasing end of the Peltier effect sheet 18 faces the outside. Since the first piezoelectric material layer 16 generates alternating current, a rectifier 19 is used to convert the alternating current into direct current to meet the working requirements of the Peltier effect sheet 18. The insulating mounting groove 17 can prevent the Peltier effect sheet 18 from leaking electricity, and the positioning sleeve 15 can also be an insulating sleeve.

[0062] When the central column 1 vibrates, the vibration kinetic energy of the central column 1 is converted into alternating current through the first piezoelectric material layer 16. The alternating current is rectified into direct current by the rectifier 19 and then transmitted to the Peltier effect sheet 18. The Peltier effect sheet 18 absorbs the heat inside the knife rod 10 and releases the heat to the outside of the knife rod 10, thereby dissipating the heat of the knife rod 10.

[0063] During cutting, each blade segment 2 generates a large amount of heat, part of which is taken away by the cutting fluid, but part of which is transferred to the shank 10, and the heat inside the shank 10 is difficult to dissipate. In the present invention, the first piezoelectric material layer 16, the rectifier 19 and the Peltier effect sheet 18 form a piezoelectric damping device, which can effectively slow down the vibration of the seismic center column 1, and at the same time promote the heat dissipation inside the shank 10, preventing the internal temperature of the shank 10 from being too high and affecting the strength.

[0064] In the present invention, the first piezoelectric material layer 16 can be made of piezoelectric ceramics, preferably polyvinylidene fluoride film, which is a flexible film with large deformation, low impedance, and can generate higher voltage.

[0065] In order to increase the electric energy provided to the Peltier effect sheet 18 and enhance the heat dissipation effect, a plurality of radially extending sleeves 110 are provided on the outer wall of the positioning sleeve 15, a pressing block 111 which slides with the sleeve 110 is provided inside the sleeve 110, a top plate 112 is fixedly provided on the top of the sleeve 110, a second piezoelectric material layer 113 is provided on the inner side wall of the top plate 112, the second piezoelectric material layer 113 may also be a polyvinylidene fluoride film, and the second piezoelectric material layer 113 is connected to the rectifier 19 through a wire; a plurality of air holes are provided on the side wall of the sleeve 110. During milling, the tool rod 10 rotates at high speed, and the pressure block 111 is subjected to centrifugal force, thereby sliding along the sleeve 110 to the inner side of the top plate 112. The centrifugal force of the pressure block 111 is transmitted to the second piezoelectric material layer 113. The second piezoelectric material layer 113 will also generate electrical energy after being compressed. The electrical energy generated by the second piezoelectric material layer 113 is transmitted to the Pettel effect sheet 18, thereby increasing the current passing through the Pettel effect sheet 18 and improving the heat absorption and heat release efficiency.

[0066] The central column 1 is provided with a flexible sleeve 114 on the outside. The flexible sleeve 114 can be a rubber sleeve. The flexible sleeve 114 is provided with a plurality of positioning grooves. A plurality of rigid blocks 115 are provided in the positioning grooves. The rigid blocks 115 contact the first piezoelectric material layer 16. The central column 1 is made of metal material, which has high hardness and strength and a small amplitude when vibrating. After the flexible sleeve 114 is provided on the outside of the central column 1, the central column 1 vibrates and drives the flexible sleeve 114 to vibrate. The rigid blocks 115 vibrate along with the flexible sleeve 114. The vibration movement can be regarded as a movement of a small distance. Since the flexible sleeve 114 has low strength and is easy to deform, when the flexible sleeve 114 moves a short distance in a certain direction and stops moving, the rigid blocks 115 will continue to move a short distance under the action of inertia, and at the same time pull the flexible sleeve 114 to deform. Therefore, the vibration amplitude of the rigid blocks 115 will be greater than the vibration amplitude of the flexible sleeve 114, thereby more effectively squeezing the first piezoelectric material layer 16 and ensuring the power generation effect of the first piezoelectric material layer 16. In addition, the elastic deformation of the flexible sleeve 114 itself can absorb the energy during vibration and optimize the shock absorption effect.

[0067] Embodiment 1

[0068] The method for preparing the blade root milling cutter of the present invention comprises:

[0069] The cemented carbide rod is used as the raw material, and the central column 1 and the plurality of blade segments 2 are obtained by machining. The cemented carbide can be specifically tungsten-cobalt cemented carbide, with grades YG3, YG6, YG8 and the like.

[0070] The central column 1 and the blade segment 2 are heat treated by using existing heat treatment processes to increase the hardness of the blade segment 2 .

[0071] A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially arranged on the surface of the blade segment 2. The transition coating is made of a high-adhesion material to enhance the bonding between the coating and the substrate; the wear-resistant coating is made of a wear-resistant material to improve the wear resistance and cutting performance of the blade segment 2; the friction-reducing coating is made of a self-lubricating material to reduce the friction resistance during cutting. Specifically, the transition coating is a CrN layer with a thickness of 1-2 μm. ； The wear-resistant coating is a TiAlN layer with a thickness of 3-5μm ； The anti-friction coating is a MoS2 layer with a thickness of 0.5-1 μm.

[0072] The advantages of this embodiment are that only one carbide rod is needed as raw material, which saves raw materials, and the central column 1 and the plurality of blade segments 2 are integrally formed, and the connection strength is high. The disadvantages are that the milling cutter structure is highly irregular, the processing difficulty is high, and the position accuracy of each blade segment 2 is difficult to ensure.

[0073] Embodiment 2

[0074] The preparation method of this embodiment comprises:

[0075] The central column 1 is obtained by machining with a cemented carbide rod as the raw material. The cemented carbide can be specifically tungsten-cobalt cemented carbide, grades YG3, YG6, YG8, etc. The central column 1 is a standard cylindrical shape, with low machining difficulty and guaranteed machining accuracy. After machining, a first positioning groove, a second positioning groove, a third positioning groove, a pin hole, and a threaded connection hole are opened on the central column 1.

[0076] A plurality of blade segments 2 are obtained by machining using a cemented carbide rod as a raw material. The material of the blade segment 2 can be the same as that of the central column 1, or can be different. For example, the blade segment 2 can be made of a material with a higher hardness. The blade segment 2 can be obtained by milling. As a preferred embodiment:

[0077] The specific processing process of blade segment 2 is as follows:

[0078] The rod is turned to obtain a first blade segment 21, a second blade segment 22 and a third blade segment 23 on the surface of the rod, and a cutting margin 24 is set at the connection between the first blade segment 21, the second blade segment 22 and the third blade segment 23 to obtain a molded blank, such as Fig. 9 As shown. The shapes of the first blade segment 21, the second blade segment 22 and the third blade segment 23 are formed simultaneously, which can improve the processing efficiency and ensure the symmetry of the two first blade segments 21. The cutting allowance 24 is a regular cylindrical shape. In the subsequent process, after the blank is cut, a certain length of material will be consumed. Therefore, an appropriate amount of cutting allowance 24 is reserved to avoid the first blade segment 21, the second blade segment 22 and the third blade segment 23 being unable to be spliced ​​into a complete formed blade after cutting. At the same time, the surface roughness is low during cutting, and a certain amount of finishing allowance is reserved.

[0079] The formed blank is milled to obtain planes symmetrical to the center line on both sides of the center line of the bar, such as Fig.10 As shown in the figure, the blank after milling is in the shape of a plate.

[0080] The formed blank is cut radially at the cutting allowance 24 to obtain Fig.11 The first blade segment 21 shown, Fig.12 The second blade segment 22 and Fig.13 As shown in the third blade segment 23 , the first blade segment 21 , the second blade segment 22 and the third blade segment 23 are all two, and the first connecting column 3 , the second connecting column 4 and the third connecting column 5 are obtained at the same time.

[0081] The cutting surfaces of the first blade segment 21, the second blade segment 22 and the third blade segment 23 are milled to the designed size.

[0082] Then, pin holes are machined at the center of the second connecting column 4 and the third connecting column 5, a threaded hole is machined at the center of the first connecting column 3, and light holes are machined on both sides of the threaded hole.

[0083] The central column 1 and the blade segment 2 are heat treated to improve the performance of the central column 1 and increase the hardness of the blade segment 2 by using existing heat treatment processes.

[0084] A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially arranged on the surface of the blade segment 2, referring to the first embodiment.

[0085] Install the blade segment 2 onto the central column 1.

[0086] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A blade root milling cutter, comprising a central column (1) and a profiled blade edge arranged on the outer wall of the central column (1), characterized in that: Each of the forming blades comprises a plurality of blade segments (2), the plurality of blade segments (2) are evenly distributed in a circular shape around the central cylinder (1), and the plurality of blade segments (2) are arranged in sequence along the axial direction of the central cylinder (1); In two adjacent blade segments (2), the end surfaces of the two blade segments (2) facing each other are located in the same plane, and the plane is perpendicular to the central column (1).

2. The blade root milling cutter according to claim 1, characterized in that: The blade segment (2) comprises a first blade segment (21), a second blade segment (22) and a third blade segment (23).

3. The blade root milling cutter according to claim 2, characterized in that: The number of each of the first blade segment (21), the second blade segment (22) and the third blade segment (23) is two, and the two first blade segments (21) are centrally symmetrical with respect to the center line of the central column (1), the two second blade segments (22) are centrally symmetrical with respect to the center line of the central column (1), and the two third blade segments (23) are centrally symmetrical with respect to the center line of the central column (1).

4. The blade root milling cutter according to claim 3, characterized in that: The two first blade segments (21) are connected as a whole via a first connecting column (3), the two second blade segments (22) are connected as a whole via a second connecting column (4), and the two third blade segments (23) are connected as a whole via a third connecting column (5); The central column (1) is provided with a first positioning groove, a second positioning groove and a third positioning groove which radially penetrate the central column (1); the first connecting column (3), the second connecting column (4) and the third connecting column (5) are respectively located in the first positioning groove, the second positioning groove and the third positioning groove; and the first connecting column (3), the second connecting column (4) and the third connecting column (5) are connected to the central column (1) via a connecting piece.

5. The blade root milling cutter according to claim 4, characterized in that: The first blade segment (21), the second blade segment (22) and the third blade segment (23) are arranged in sequence from the milling end to the clamping end. The connecting piece includes a connecting screw (6) and a positioning pin (7). The first connecting column (3) is connected to the central column (1) by two screws (6). A threaded hole is arranged at the center of the first connecting column (3). Pin holes are arranged at the centers of the second connecting column (4) and the third connecting column (5). The pin holes are coaxial with the threaded holes and are connected to the threaded holes. The positioning pin (7) is interference fit with the pin holes. A locking screw (8) is arranged in the threaded hole, and the locking screw (8) presses the end of the positioning pin (7) tightly.

6. The method for preparing the blade root milling cutter according to claim 1, characterized in that: include Using a cemented carbide rod as a raw material, machining is performed to obtain a central column (1) and a plurality of blade segments (2); Performing heat treatment on the central column (1) and the blade segment (2); A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially arranged on the surface of the blade segment (2).

7. The preparation method according to claim 6, characterized in that: The transition coating is a CrN layer with a thickness of 1-2 μm; the wear-resistant coating is a TiAlN layer with a thickness of 3-5 μm; and the friction-reducing coating is a MoS2 layer with a thickness of 0.5-1 μm.

8. The method for preparing a blade root milling cutter according to any one of claims 1 to 5, characterized in that: include A central cylinder (1) is obtained by machining a cemented carbide rod as a raw material; Using a carbide rod as a raw material, machining to obtain a plurality of blade segments (2); Performing heat treatment on the central column (1) and the blade segment (2); A transition coating, a wear-resistant coating and a friction-reducing coating are sequentially provided on the surface of the blade segment (2); Install the blade segment (2) onto the center column (1).

9. The preparation method according to claim 8, characterized in that: The process of machining a plurality of blade segments (2) using a cemented carbide rod as a raw material is as follows: The rod is turned to obtain a first blade segment (21), a second blade segment (22) and a third blade segment (23) on the surface of the rod, and a cutting margin (24) is set at the connection between the first blade segment (21), the second blade segment (22) and the third blade segment (23) to obtain a formed blank; The formed blank is milled to obtain planes symmetrical with respect to the center line on both sides of the center line of the bar; The formed blank is cut radially at the cutting margin (24) to obtain a first blade segment (21), a second blade segment (22) and a third blade segment (23); The cutting surfaces of the first blade segment (21), the second blade segment (22) and the third blade segment (23) are milled to the designed size.

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