Integral hard alloy forming milling cutter with auxiliary chip flutes

Abstract

The invention provides an integral hard alloy forming milling cutter with an auxiliary chip pocket, which comprises a working part and an optional connecting part used for being directly or indirectly connected with a machine tool, and each cutting edge is independently provided with a front cutter surface, a rear cutter surface and a cutting edge formed by the intersection of the front cutter surface and the rear cutter surface, the front cutter surface forms a first front angle at each position of the cutting edge, and is characterized in that the front cutter surface is provided with an auxiliary chip pocket, the auxiliary chip pocket extends along the direction of the cutting edge in the length direction, the auxiliary chip pocket is provided with a pocket surface close to the cutting edge, and the pocket surface is provided with a groove surface close to the cutting edge. Therefore, a second front angle is formed on the groove face, close to the cutting edge, of the auxiliary chip containing groove, and the second front angle is larger than the corresponding first front angle. The second front angle is formed by arranging the auxiliary chip flutes, the sharp large front angle of the cutting edge is formed, the negative front angle is changed into the positive front angle, the cutting efficiency is greatly improved, the cutting resistance is reduced, and the service life of the cutter is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of milling cutters, in particular to an integral carbide forming milling cutter with a secondary chip groove and a method for increasing the sharpness of the integral carbide forming milling cutter. Background Art

[0002] A milling cutter is a widely used multi-tooth, multi-blade rotary tool. During milling, the milling cutter rotates around its axis as the main motion, while the workpiece performs the feed motion. Milling cutters are typically used for high-speed cutting, resulting in high impact and vibration during machining. Forming milling cutters are a type of milling cutter whose cutting edge profile is designed and calculated based on the shape of the workpiece's forming surface. Because a milling cutter is a multi-blade tool, it has a high milling speed and no idle travel, making it a highly efficient cutting method that can process not only planes, grooves, and steps, but also threads, splines, gears, and other forming surfaces. Existing milling cutters suffer from the problem of not being able to balance cutting speed and structural strength. In particular, the high-precision machining of blades, impellers, and impellers for aircraft engine components and steam turbine components places extremely high demands on tool performance. Existing tools cannot meet these requirements in terms of machining accuracy, cutting speed, and service life, which has hindered the production progress of these projects. Existing technologies typically use cutting tools made of high-speed steel and cemented carbide. High-speed steel, due to its toughness, makes it easier to achieve a sharp edge. However, due to the material's properties, high-speed machining is difficult, and high-speed steel milling cutters have a short service life. Cemented carbide is heat-resistant and suitable for high-speed machining, but due to the limitations of existing tool manufacturing processes, it cannot achieve the sharp, high-rake angle cutting edge required for form milling cutters. This results in poor tool processing accuracy, low cutting efficiency, and a short service life, failing to meet industry demands. There is an urgent need to improve tool processing efficiency, precision, and service life. Summary of the Invention

[0003] The present application provides a solid carbide forming milling cutter with a secondary chip groove and a method for increasing the sharpness of the solid carbide forming milling cutter, which includes the following embodiments:

[0004] Embodiment 1. A solid carbide forming milling cutter with a secondary chip groove, comprising a working part and an optional connecting part for directly or indirectly connecting to a machine tool, wherein at least the working part is made of carbide, the working part having multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently having a front cutting face, a back cutting face and a cutting edge formed by the intersection of the front cutting face and the back cutting face, the front cutting face forming a first rake angle at each location of the cutting edge, characterized in that a secondary chip groove is provided on the front cutting face, the secondary chip groove extends in the length direction along the direction of the cutting edge, the secondary chip groove has a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle.

[0005] Embodiment 2. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the second rake angle is 3 to 65 degrees larger than the corresponding first rake angle, such as 10 to 60 degrees, such as 20 to 40 degrees.

[0006] Embodiment 3. The integral carbide forming milling cutter according to embodiment 1 is characterized in that the first rake angle has the following degrees: 0 degrees, greater than 0 degrees, and less than 0 degrees, wherein the secondary chip groove is at least arranged on the rake face formed at the cutting edge with a first rake angle less than 0 degrees; or the first rake angle is 0 degrees.

[0007] Embodiment 4. The solid carbide forming milling cutter according to embodiment 2 is characterized in that the second rake angle is greater than 7 degrees, greater than 10 degrees, greater than 15 degrees, or greater than 35 degrees.

[0008] Embodiment 5. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the width of the secondary chip groove is 0.15 mm to 3 mm or 3% to 30% of the milling cutter diameter.

[0009] Embodiment 6. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the depth of the secondary chip groove is 0.1 to 1.5 mm.

[0010] Embodiment 7. The integral carbide forming milling cutter according to embodiment 1 is characterized in that the groove surface of the secondary chip groove close to the cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, which is connected to the groove surface close to the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

[0011] Embodiment 8. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the diameter of the milling cutter is 5 mm to 50 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

[0012] Embodiment 9. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0013] Embodiment 10. The solid carbide forming milling cutter according to embodiment 1 is characterized in that the secondary chip groove is prepared by a femtosecond pulse laser processing method.

[0014] Embodiment 11. A method for increasing the sharpness of a solid carbide forming milling cutter, wherein the solid carbide forming milling cutter includes a working part and an optional connecting part for directly or indirectly connecting to a machine tool, wherein at least the working part is made of carbide, the working part has multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently have a front cutting face, a back cutting face and a cutting edge formed by the intersection of the front cutting face and the back cutting face, the front cutting face forms a first rake angle at each location of the cutting edge, the method comprising: forming a secondary chip groove on the front cutting face, the secondary chip groove extending in the length direction along the direction of the cutting edge, the secondary chip groove having a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle.

[0015] Embodiment 12. The method according to embodiment 11 is characterized in that the second rake angle is 3 degrees to 65 degrees larger than the corresponding first rake angle, such as 10 to 60 degrees, such as 20 to 40 degrees.

[0016] Embodiment 13. The method according to embodiment 11 is characterized in that the first rake angle has the following degrees: 0 degrees, greater than 0 degrees, and less than 0 degrees, wherein the secondary chip groove is at least arranged on the rake face formed at the cutting edge with a first rake angle less than 0 degrees; or the first rake angle is 0 degrees.

[0017] Embodiment 14. The method according to embodiment 12 is characterized in that the second rake angle is greater than 7 degrees, greater than 10 degrees, greater than 15 degrees, or greater than 35 degrees.

[0018] Embodiment 15. The method according to embodiment 11, characterized in that the width of the secondary chip groove is 0.15 mm to 3 mm or 3% to 30% of the diameter of the milling cutter.

[0019] Embodiment 16. The method according to embodiment 11, characterized in that the depth of the secondary chip groove is 0.1 to 1.5 mm.

[0020] Embodiment 17. The method according to embodiment 11 is characterized in that the groove surface of the secondary chip groove close to the cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, which is connected to the groove surface close to the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

[0021] Embodiment 18. The method according to embodiment 11 is characterized in that the diameter of the milling cutter is 5 mm to 50 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

[0022] Embodiment 19. The method according to embodiment 11 is characterized in that the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0023] Embodiment 20. The method according to embodiment 11 is characterized in that the secondary chip groove is prepared by a femtosecond pulse laser processing method.

[0024] This application also includes the following technical solutions:

[0025] Solution 1. A spiral groove forming milling cutter, which comprises a forming milling cutter body part and an optional connecting part for directly or indirectly connecting to a machine tool, at least the forming milling cutter body part is made of solid carbide, the forming milling cutter body part has multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently have a front cutting face, a back cutting face and a cutting edge, the front cutting face forms a first front angle at each location of the cutting edge, the main chip groove is a spiral groove, each of the cutting edges comprises at least one cutting tooth, the back cutting face of the cutting tooth is divided into a negative angle face, a positive angle face and a side face, thereby corresponding to three types of cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side face cutting edge, characterized in that,

[0026] A secondary chip groove is provided on the front cutting edge, and the secondary chip groove extends in the length direction along the direction of the negative angle surface cutting edge. The secondary chip groove has a groove surface close to the negative angle surface cutting edge, so that the groove surface of the secondary chip groove close to the negative angle surface cutting edge forms a second front angle of the negative angle surface, and the second front angle of the negative angle surface is greater than the corresponding first front angle.

[0027] Solution 2. The spiral groove forming milling cutter according to Solution 1 is characterized in that the second rake angle of the negative angle surface is 3 degrees to 65 degrees larger than the first rake angle, for example, 5 degrees to 35 degrees.

[0028] Solution 3. The spiral groove forming milling cutter according to Solution 1 is characterized in that the angle of the spiral groove is the angle between the direction of the spiral and the main axis, and the angle of the spiral groove is between 3 and 55 degrees, for example, 15 to 50 degrees, for example, 25 to 45 degrees; the secondary chip groove also extends in the length direction along the direction of the side cutting edge, and the secondary chip groove has a groove surface close to the side cutting edge, so that the groove surface of the secondary chip groove close to the side cutting edge forms a second side rake angle, and the second side rake angle is greater than the corresponding first rake angle.

[0029] Option 4. The spiral groove forming milling cutter according to Option 2 is characterized in that the secondary chip groove extends along the entire cutting edge, so that all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees, greater than or equal to 10 degrees and less than or equal to 35 degrees, greater than or equal to 15 degrees and less than or equal to 25 degrees, or greater than or equal to 27 degrees and less than or equal to 40 degrees.

[0030] Solution 5. The spiral groove forming milling cutter according to Solution 1 is characterized in that the width of the secondary chip groove is 0.15 mm to 3 mm or 3% to 30% of the milling cutter diameter.

[0031] Solution 6. The spiral groove forming milling cutter according to Solution 1 is characterized in that the depth of the secondary chip groove is 0.1 to 2 mm, or 0.3 to 1.5 mm.

[0032] Solution 7. The spiral groove forming milling cutter according to Solution 1 is characterized in that the groove surface of the secondary chip groove close to the negative angle edge and / or the groove surface close to the side edge is wavy and extends along the direction of the edge, or the secondary chip groove has a groove bottom surface, the groove bottom surface is connected to the groove surface close to the negative angle edge and / or the groove surface close to the side edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

[0033] Solution 8. The spiral groove forming milling cutter according to Solution 1 is characterized in that the diameter of the milling cutter is 5 mm to 80 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

[0034] Solution 9. The spiral groove forming milling cutter according to Solution 1 is characterized in that the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0035] Solution 10. The spiral groove forming milling cutter according to Solution 1 is characterized in that the secondary chip groove is prepared by a femtosecond pulse laser processing method.

[0036] Solution 11. A method for increasing the sharpness of a spiral groove forming milling cutter, wherein the spiral groove forming milling cutter comprises a forming milling cutter body portion and an optional connecting portion for directly or indirectly connecting to a machine tool, at least the forming milling cutter body portion is made of solid carbide, the forming milling cutter body portion has a plurality of cutting edges and a plurality of main chip grooves corresponding to the cutting edges, the cutting edges each independently have a rake face, a flank face and a cutting edge, the rake face forms a first rake angle at each location of the cutting edge, the main chip groove is a spiral groove, each of the cutting edges The blade includes at least one cutting tooth, and the back cutting surface of the cutting tooth is divided into a negative angle surface, a positive angle surface and a side surface, thereby corresponding to three types of cutting edges, namely, a negative angle cutting edge, a positive angle cutting edge and a side cutting edge. It is characterized in that the method includes: forming a secondary chip groove on the front cutting edge, the secondary chip groove extends in the length direction along the direction of the negative angle cutting edge, the secondary chip groove has a groove surface close to the negative angle cutting edge, so that the groove surface of the secondary chip groove close to the negative angle cutting edge forms a second front angle of the negative angle surface, and the second front angle of the negative angle surface is greater than the corresponding first front angle.

[0037] Option 12. The method according to Option 11 is characterized in that the second rake angle of the negative angle surface is 3 degrees to 65 degrees larger than the first rake angle, for example, 5 degrees to 35 degrees, for example, 3 degrees to 35 degrees.

[0038] Option 13. The method according to Option 11 is characterized in that the angle of the spiral groove is the angle between the direction of the spiral and the main axis, and the angle of the spiral groove is between 3 and 55 degrees, for example, 15 to 50 degrees, for example, 25 to 45 degrees; the secondary chip groove also extends in the length direction along the direction of the side cutting edge, and the secondary chip groove has a groove surface close to the side cutting edge, so that the groove surface of the secondary chip groove close to the side cutting edge forms a second side rake angle, and the second side rake angle is greater than the corresponding first rake angle.

[0039] Option 14. The method according to Option 12 is characterized in that the secondary chip groove extends along the entire cutting edge, so that all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees, greater than or equal to 10 degrees and less than or equal to 35 degrees, greater than or equal to 15 degrees and less than or equal to 25 degrees, or greater than or equal to 27 degrees and less than or equal to 40 degrees.

[0040] Solution 15. The method according to Solution 11 is characterized in that the width of the secondary chip groove is 0.15 mm to 3 mm or 3% to 30% of the milling cutter diameter.

[0041] Solution 16. The method according to Solution 11, characterized in that the depth of the secondary chip groove is 0.1 to 2 mm, or 0.3 to 1.5 mm.

[0042] Option 17. The method according to Option 11 is characterized in that the groove surface of the secondary chip groove close to the negative angle edge and / or the groove surface close to the side edge is wavy and extends along the direction of the edge, or the secondary chip groove has a groove bottom surface, which is connected to the groove surface close to the negative angle edge and / or the groove surface close to the side edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

[0043] Option 18. The method according to Option 11 is characterized in that the diameter of the milling cutter is 5 mm to 80 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

[0044] Option 19. The method according to Option 11 is characterized in that the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0045] Solution 20. The method according to Solution 11 is characterized in that the auxiliary chip groove is prepared by a femtosecond pulse laser processing method.

[0046] The present application provides a secondary chip groove and extends the secondary chip groove in the direction of the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle greater than the corresponding first rake angle, or all actual rake angles are within a specific range, thereby effectively solving the problem of negative rake angle or too small rake angle of the forming milling cutter cutting edge. By increasing the rake angle of the cutting edge, the negative rake angle is converted into a positive rake angle, thereby making cutting easier, effectively reducing cutting resistance, and making the processing accuracy higher and the tool life longer, so that the tool can maintain processing accuracy even after long-term use. The present application also further strengthens the overall strength of the milling cutter and the linear speed during processing by providing a wavy groove surface and / or a wavy groove bottom surface, thereby improving processing efficiency. The tested life of the milling cutter using the technical solution of the present application is 2-5 times that of the tool life of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0048] Figure 1 This is a front view of the solid carbide forming milling cutter in Example 1;

[0049] Figure 2 Schematic diagram of the working part of the solid carbide forming milling cutter in Example 1;

[0050] Figure 3 Schematic diagram of a chip cutting edge of the solid carbide forming milling cutter in Example 1;

[0051] Figure 4 It is a right side view of the solid carbide forming milling cutter in Example 1;

[0052] Figure 5 for Figure 2 AA section view of the solid carbide forming milling cutter;

[0053] Figure 6 for Figure 5 The enlarged view of the part in the dotted box;

[0054] Figure 7 Schematic diagram of the solid carbide forming milling cutter in Example 2;

[0055] Figure 8 A three-dimensional diagram of a spiral groove forming milling cutter;

[0056] Figure 9 A schematic diagram of the main body of a spiral groove forming milling cutter;

[0057] Figure 10 This is the main view of the spiral groove forming milling cutter body;

[0058] Figure 11 It is a partial cross-sectional view of the spiral groove forming milling cutter;

[0059] Figure 12 for Figure 11 AA section view of the spiral groove forming milling cutter;

[0060] Figure 13 for Figure 12 The partially enlarged schematic diagram in the dotted box;

[0061] Figure 14 for Figure 11 The partially enlarged schematic diagram in the dotted box;

[0062] Figure 15 for Figure 14 BB cross-sectional view of the cutting teeth of the spiral groove forming milling cutter;

[0063] Figure 16 Schematic diagram of the wavy groove surface and groove bottom in Example 5;

[0064] Figure 17 Schematic diagram of the main body of the spiral groove forming milling cutter of Example 7.

[0065] Description of the drawings: 10-secondary chip groove, 11-groove surface, 12-groove bottom surface, 20-working part (main body part), 30-connecting part, 100-cutting edge, 110-front cutting edge, 120-back cutting edge, 121-negative angle surface, 122-positive angle surface, 123-side, 130-cutting edge, 131-negative angle cutting edge, 132-positive angle cutting edge, 133-side cutting edge, 200-main chip groove, 300-cutting tooth. DETAILED DESCRIPTION

[0066] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0067] The present application discloses an integral carbide forming milling cutter with a secondary chip groove, which includes a working part and an optional connecting part for directly or indirectly connecting to a machine tool, wherein at least the working part is made of carbide, the working part has multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently have a front cutting face, a back cutting face and a cutting edge formed by the intersection of the front cutting face and the back cutting face, the front cutting face forms a first rake angle at each location of the cutting edge, and is characterized in that a secondary chip groove is provided on the front cutting face, the secondary chip groove extends in the length direction along the direction of the cutting edge, the secondary chip groove has a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle.

[0068] In this application, a milling cutter used for machining a formed surface and having a cutting edge profile designed according to the workpiece profile is referred to as a forming milling cutter.

[0069] For the purposes of this application, the term "first rake angle" refers to the angle between the rake and flank faces (without a clearance design) minus 90 degrees. A larger first rake angle indicates a sharper cutting edge. The angle between the intersection of a plane perpendicular to the cutting edge and the rake and flank faces at the cutting edge is the angle between the rake and flank faces (without a clearance design).

[0070] The "second rake angle" in this application refers to the value obtained by subtracting the angle between the flute surface of the secondary chip groove near the cutting edge and the flank surface in the absence of a clearance design from 90 degrees. At the cutting edge where the secondary chip groove is provided, a plane perpendicular to the cutting edge is drawn. The angle between the intersection of the plane, the flute surface of the secondary chip groove near the cutting edge and the flank surface at the cutting edge is the angle between the flute surface of the secondary chip groove near the cutting edge and the flank surface in the absence of a clearance design. For some selected points on the cutting edge, there are both a first rake angle and a second rake angle. In this case, the first rake angle is the first rake angle corresponding to the second rake angle of the selected point on the cutting edge.

[0071] The present application provides a secondary chip groove extending along the cutting edge to form a second rake angle greater than the corresponding first rake angle, effectively solving the problem of a negative rake angle or too small rake angle of the cutting edge of a spiral groove forming milling cutter. The negative rake angle is converted into a positive rake angle, which significantly improves the sharpness of the spiral groove forming milling cutter, reduces cutting resistance, reduces thermal damage to the workpiece surface, greatly improves cutting efficiency and cutting accuracy, thereby improving processing accuracy and enabling the tool to maintain processing accuracy even after long-term use, thereby greatly improving the life of the milling cutter. The present application limits the forming milling cutter body to a solid carbide material. The various processing methods in the prior art do not distribute the direction of sharpness improvement along the cutting edge, making it impossible to achieve a similar large rake angle for all cutting edges, resulting in poor tool processing accuracy, processing efficiency, and processing life. Milling cutters made of the same material, due to the lack of secondary chip grooves distributed along the cutting edge in existing technologies, have high cutting resistance, and the Ti alloy will produce a Ti alloy hardened layer, which can easily cause cracks in the workpiece, thus shortening the workpiece life. Furthermore, the presence of a large negative angle increases friction between the tool and the workpiece, not only producing a hardened layer but also causing tool yield, which directly affects machining accuracy and is unacceptable in high-precision machining. However, the profiled milling cutter of the present application can maintain good sharpness without the hardened layer, cracks, or tool yield.

[0072] Those skilled in the art understand that the integral carbide forming milling cutter with secondary chip grooves of the present application can have one cutting tooth, two cutting teeth or multiple cutting teeth. In the case where the milling cutter has two cutting teeth or multiple cutting teeth, if the first rake angle includes angles of 0 degrees, greater than 0 degrees, and less than 0 degrees, then areas with these angles will be present on each cutting tooth, that is, the milling cutter will have multiple areas with a first rake angle greater than 0 degrees, multiple areas with a first rake angle less than 0 degrees, and multiple areas with a first rake angle equal to 0 degrees. In this case, it is actually impossible to set the secondary chip groove using the grinding method of the prior art. This is because the grinding wheel is too large to correspond to the direction of each cutting edge, the positions that need to be ground are too many and too complex, and the size of the secondary chip groove is small enough, making it difficult for the grinding process to achieve the required precision.

[0073] In this application, cemented carbide has the usual meaning understood by those skilled in the art. In this field, cemented carbide is a powder metallurgy product made of micron-sized powder of high-hardness refractory metal carbide (WC, TiC) as the main component, cobalt (Co) or nickel (Ni), molybdenum (Mo) as a binder, and sintered in a vacuum furnace or a hydrogen reduction furnace. Its toughness is much higher than that of high-speed steel, about 800 to 1000 ° C, and the allowed cutting speed is about 4 to 10 times that of high-speed steel. The hardness is very high, up to (89 to 91) HRA, and some are as high as 93 HRA; but its bending strength is 1.1 to 1.5 GPa, which is only half of that of high-speed steel; the impact toughness is 0.04 MJ / m 2 About, less than 1 / 25 to 1 / 10 of high-speed steel. Due to its good heat resistance and wear resistance, it is increasingly used in cutting tools with less complex blade shapes. The cemented carbide described in this application includes one selected from the following: for example, tungsten-cobalt (WC-Co) cemented carbide, tungsten-titanium-cobalt (WC-Ti-Co) cemented carbide, tungsten-titanium-tantalum (niobium) (WC-TaC (NbC)-Co) cemented carbide, tungsten-titanium-cobalt-tantalum (niobium) (WC-Ti C-TaC (NbC)-Co) cemented carbide and other WC-based cemented carbides, or TiC-based cemented carbide, fine-grained and ultrafine-grained cemented carbide, steel-bonded cemented carbide, coated cemented carbide, etc.

[0074] In some embodiments, the second rake angle is greater than the corresponding first rake angle by 3 to 65 degrees, for example, 10 to 60 degrees, and for example, 20 to 40 degrees. Those skilled in the art may adjust this as needed. Generally, the smaller the first rake angle at any selected point on the cutting edge, the larger the second rake angle formed by providing the secondary chip flute should be, thereby achieving a sharp cutting edge.

[0075] In some embodiments, the first rake angle has the following degrees: 0 degrees, greater than 0 degrees, and less than 0 degrees, wherein the secondary chip groove is at least provided on the rake face with a first rake angle less than 0 degrees formed at the cutting edge; or the first rake angle is all 0 degrees. The chip cutting edge with a first rake angle less than 0 degrees formed at the cutting edge has low sharpness. During the milling process, the cutting resistance is large, the corresponding cutting edge portion is subjected to large force, and is severely worn, resulting in a short life of the milling cutter. By providing the secondary chip groove at least on the rake face with a first rake angle less than 0 degrees formed at the cutting edge, it is possible to achieve at the lowest cost that the actual rake angle of all low-sharpness cutting edges of the cutting edge is greater than 0 degrees, thereby achieving a sharp large rake angle along the entire cutting edge. In the present application, the cutting edge rake angle of any selected point of the cutting edge that meets the sharpness requirements of the forming milling cutter is defined as the "actual rake angle", which is an indicator for measuring the sharpness of the forming milling cutter in the working state of the present application. For a cutting edge that can meet the sharpness requirements of the forming milling cutter without setting a secondary chip groove, the actual rake angle of any selected point is the first rake angle of the selected point. For a cutting edge that is provided with a secondary chip groove to meet the sharpness requirements of the forming milling cutter, the actual rake angle of any selected point is the second rake angle of the selected point. The present application achieves that all actual rake angles are greater than 0 degrees by setting the secondary chip groove at least on the rake face where the first rake angle formed at the cutting edge is less than 0 degrees, thereby reducing cutting resistance, reducing thermal damage to the workpiece surface, greatly improving cutting efficiency and cutting accuracy, thereby improving machining accuracy, and enabling the tool to maintain machining accuracy even after long-term use, thereby greatly improving the life of the milling cutter.

[0076] In some embodiments, all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees, greater than or equal to 10 degrees and less than or equal to 35 degrees, greater than or equal to 15 degrees and less than or equal to 25 degrees, or greater than or equal to 27 degrees and less than or equal to 40 degrees. Those skilled in the art can reasonably set the secondary chip groove according to the rake angles of different cutting edge areas, and ultimately make the actual rake angle of the entire cutting edge meet the range defined in this application, so that the sharpness is improved along the direction of the cutting edge distribution, while ensuring processing accuracy, improving cutting efficiency, reducing cutting resistance, and extending tool life.

[0077] In some embodiments, the second rake angle is greater than 7 degrees, greater than 10 degrees, greater than 15 degrees, or greater than 35 degrees. Those skilled in the art can reasonably set the secondary chip groove according to the rake angles of different cutting edge areas, and ultimately make the second rake angle of the entire cutting edge meet the range defined in this application, so that the sharpness is improved along the direction of the cutting edge distribution, while ensuring processing accuracy, improving cutting efficiency, reducing cutting resistance, and extending tool life.

[0078] In some embodiments, the width of the secondary chip groove is 0.15mm to 3mm or 3% to 30% of the milling cutter diameter. For example, the width of the secondary chip groove is 0.3mm to 2.5mm, or 0.5mm to 2mm, or 0.8mm to 1.8mm, or 1mm to 1.5mm, or the width of the secondary chip groove is 3% to 30% of the milling cutter diameter, or 5% to 25%, or 8% to 18%, or 10% to 15%. The secondary chip groove width refers to the dimension of the secondary chip groove on the rake face perpendicular to the direction of extension of the cutting edge, and the milling cutter diameter refers to the diameter of the maximum outer circle of the cutting edge rotation when the milling cutter is in operation.

[0079] In some embodiments, the depth of the secondary chip flute is 0.1 to 1.5 mm.

[0080] In some embodiments, the groove surface of the secondary chip groove near the cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, the groove bottom surface is connected to the groove surface near the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy. The wavy extension of the groove surface or the wavy undulation of the groove bottom surface can not only play the role of reinforcing ribs, but also improve the strength of the cutting edge without reducing the sharpness of the cutting edge, and improve the durability of the cutting edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after long-term use, reduce thermal damage to the workpiece surface, and further increase the linear speed during milling. Practice has shown that when the groove surface near the cutting edge of the secondary chip groove is wavy, the tool can be processed at a higher linear speed, the performance of the tool is stable, and the accuracy of the workpiece can also be guaranteed, thereby improving the processing efficiency.

[0081] In some embodiments, the diameter of the milling cutter is 5 mm to 50 mm, such as 8 mm to 40 mm, or 10 mm to 30 mm.

[0082] In some embodiments, the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0083] In some embodiments, the secondary chip grooves are fabricated using a femtosecond pulse laser processing method. During femtosecond pulse laser processing, the total amount of heat provided each time is small and concentrated. Before the heat generated by processing is transferred to the workpiece, the cutting chips have already vaporized, removing a large amount of heat. In other words, the rate at which the cutting chips vaporize and remove heat is greater than the rate at which heat is transferred within the workpiece, thus preventing thermal damage to the workpiece surface. In contrast, other existing laser processing methods provide a larger amount of heat at a time, which can easily cause thermal damage to the workpiece surface.

[0084] The preparation method of the forming milling cutter in the prior art is known to those skilled in the art and includes the following steps: 1. Calculating the profile of the forming milling cutter according to actual needs and selecting a suitable cemented carbide rod; 2. Starting from the cemented carbide rod, the cemented carbide rod is ground to form a blank of the forming milling cutter; 3. Forming a semi-finished product of the forming milling cutter by fine grinding; 4. The semi-finished product is subjected to PVD coating treatment to form a finished product of the forming milling cutter.

[0085] The present application provides a method for increasing the sharpness of a profile milling cutter, which primarily involves machining a secondary chip groove on a semi-finished product, and then subjecting the semi-finished product with the secondary chip groove to a PVD coating. Furthermore, the present application also provides a method for treating a profile milling cutter (whether the profile milling cutter is scrapped or not), which comprises optionally grinding the rake face of the profile milling cutter, providing the profile milling cutter with a secondary chip groove, and then subjecting the profile milling cutter with the secondary chip groove to a PVD coating.

[0086] Therefore, the present application also discloses a method for increasing the sharpness of a solid carbide forming milling cutter, wherein the solid carbide forming milling cutter includes a working part and an optional connecting part for directly or indirectly connecting to a machine tool, wherein at least the working part is made of carbide, the working part has multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently have a front cutting face, a back cutting face and a cutting edge formed by the intersection of the front cutting face and the back cutting face, the front cutting face forms a first rake angle at each point of the cutting edge, the method includes: forming a secondary chip groove on the front cutting face, the secondary chip groove extending in the length direction along the direction of the cutting edge, the secondary chip groove having a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle.

[0087] The present application provides a secondary chip groove extending along the cutting edge to form a second rake angle greater than the corresponding first rake angle, effectively solving the problem of a negative rake angle or too small rake angle of the cutting edge of a spiral groove forming milling cutter. The negative rake angle is converted into a positive rake angle, which significantly improves the sharpness of the spiral groove forming milling cutter, reduces cutting resistance, reduces thermal damage to the workpiece surface, greatly improves cutting efficiency and cutting accuracy, thereby improving processing accuracy and enabling the tool to maintain processing accuracy even after long-term use, thereby greatly improving the life of the milling cutter. The present application limits the forming milling cutter body to a solid carbide material. The various processing methods in the prior art do not distribute the direction of sharpness improvement along the cutting edge, making it impossible to achieve a similar large rake angle for all cutting edges, resulting in poor tool processing accuracy, processing efficiency, and processing life. Milling cutters made of the same material, due to the lack of secondary chip grooves distributed along the cutting edge in existing technologies, have high cutting resistance, and the Ti alloy will produce a Ti alloy hardened layer, which can easily cause cracks in the workpiece, thus shortening the workpiece life. Furthermore, the presence of a large negative angle increases friction between the tool and the workpiece, not only producing a hardened layer but also causing tool yield, which directly affects machining accuracy and is unacceptable in high-precision machining. However, the profiled milling cutter of the present application can maintain good sharpness without the hardened layer, cracks, or tool yield.

[0088] In some embodiments, the second rake angle is greater than the corresponding first rake angle by 3 to 65 degrees, for example, 10 to 60 degrees, and for example, 20 to 40 degrees. Those skilled in the art may adjust this as needed. Generally, the smaller the first rake angle at any selected point on the cutting edge, the larger the second rake angle formed by providing the secondary chip flute should be, thereby achieving a sharp cutting edge.

[0089] In some embodiments, the first rake angle has the following degrees: 0 degrees, greater than 0 degrees, and less than 0 degrees, wherein the secondary chip groove is at least provided on the rake face with a first rake angle less than 0 degrees formed at the cutting edge; or the first rake angle is all 0 degrees. The chip cutting edge with a first rake angle less than 0 degrees formed at the cutting edge has low sharpness. During the milling process, the cutting resistance is large, the corresponding cutting edge portion is subjected to large force, and is severely worn, resulting in a short life of the milling cutter. By providing the secondary chip groove at least on the rake face with a first rake angle less than 0 degrees formed at the cutting edge, it is possible to achieve at the lowest cost that the actual rake angle of all low-sharpness cutting edges of the cutting edge is greater than 0 degrees, thereby achieving a sharp large rake angle along the entire cutting edge. The present application achieves that all actual rake angles are greater than 0 degrees by arranging the auxiliary chip groove at least on the rake face with a first rake angle less than 0 degrees formed at the cutting edge, thereby reducing cutting resistance, reducing thermal damage to the workpiece surface, greatly improving cutting efficiency and cutting accuracy, thereby improving machining accuracy, and enabling the tool to maintain machining accuracy even after long-term use, thereby greatly improving the life of the milling cutter.

[0090] In some embodiments, the second rake angle is greater than 7 degrees, greater than 10 degrees, greater than 15 degrees, or greater than 35 degrees. Those skilled in the art can reasonably set the secondary chip groove according to the rake angles of different cutting edge areas, and ultimately make the second rake angle of the entire cutting edge meet the range defined in this application, so that the sharpness is improved along the direction of the cutting edge distribution, while ensuring processing accuracy, improving cutting efficiency, reducing cutting resistance, and extending tool life.

[0091] In some embodiments, the width of the secondary chip groove is 0.15mm to 3mm or 3% to 30% of the diameter of the milling cutter. For example, the width of the secondary chip groove is 0.3mm to 2.5mm, or 0.5mm to 2mm, or 0.8mm to 1.8mm, or 1mm to 1.5mm, or the width of the secondary chip groove is 3% to 30% of the diameter of the milling cutter, or 5% to 25%, or 8% to 18%, or 10% to 15%.

[0092] In some embodiments, the depth of the secondary chip flute is 0.1 to 1.5 mm.

[0093] In some embodiments, the groove surface of the secondary chip groove near the cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, the groove bottom surface is connected to the groove surface near the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy. The wavy extension of the groove surface or the wavy undulation of the groove bottom surface can not only play the role of reinforcing ribs, but also improve the strength of the cutting edge without reducing the sharpness of the cutting edge, and improve the durability of the cutting edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after long-term use, reduce thermal damage to the workpiece surface, and further increase the linear speed during milling. Practice has shown that when the groove surface near the cutting edge of the secondary chip groove is wavy, the tool can be processed at a higher linear speed, the performance of the tool is stable, and the accuracy of the workpiece can also be guaranteed, thereby improving the processing efficiency.

[0094] In some embodiments, the diameter of the milling cutter is 5 mm to 50 mm, such as 8 mm to 40 mm, or 10 mm to 30 mm.

[0095] In some embodiments, the secondary chip groove is manufactured using a processing method that does not cause thermal damage, so that no thermal damage layer exists at the secondary chip groove, and the tool strength will not be degraded due to thermal damage after the secondary chip groove is provided.

[0096] In some embodiments, the secondary chip groove is prepared by a femtosecond pulse laser processing method. The secondary chip groove described in the present application can be prepared by femtosecond pulse laser processing and forming, for example, a precision CNC laser machine purchased from DMG Mori Seiki Machine Tool Trading Co., Ltd. under the trade name LASERTEC 50Shape can be used. It is generally believed that laser processing and forming will deteriorate the performance of cemented carbide. For example, picosecond and nanosecond processing will cause thermal damage, forming a thermal damage layer in the secondary chip groove area, damaging the tool, and the surface finish is very poor. Not only can it not meet the finishing requirements, but the tool life is sharply reduced. Without being limited by theory, it is believed that the reason for the generation of such a thermal damage layer is that the high temperature generated during the processing causes the cemented carbide to oxidize, the microstructure in the alloy changes, and the hardness and wear resistance are reduced. This can be clearly found by comparing the life of the tool with that without the thermal damage layer. The life of the tool with the thermal damage layer is often less than half of the tool without the thermal damage layer, and some even deteriorate to one-fifth of the normal life or even shorter. The use of femtosecond pulse laser processing, due to its extremely fast speed, will not cause thermal damage, and the surface finish can reach 0.1-0.2nm, or even mirror finish, which is suitable for fine processing. After setting the secondary chip groove, the sharpness of the tool edge is significantly improved, greatly reducing the cutting resistance and tool wear. At the same time, the tool life is increased by 2-5 times, achieving high-precision, high-flexibility and high-efficiency processing.

[0097] The present application also discloses a spiral groove forming milling cutter, which includes a forming milling cutter body part and an optional connecting part for directly or indirectly connecting to a machine tool, at least the forming milling cutter body part is made of solid carbide, the forming milling cutter body part has multiple cutting edges and multiple main chip grooves corresponding to the cutting edges, the cutting edges each independently have a front cutting face, a back cutting face and a cutting edge, the front cutting face forms a first rake angle at each cutting edge, the main chip groove is a spiral groove, each of the cutting edges includes at least one cutting tooth, the back cutting face of the cutting tooth is divided into a negative angle face, a positive angle face and a side face, thereby corresponding to three types of cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side face cutting edge, characterized in that a secondary chip groove is provided on the front cutting face, the secondary chip groove extends in the length direction along the direction of the negative angle face cutting edge, the secondary chip groove has a groove face close to the negative angle face cutting edge, so that the groove face of the secondary chip groove close to the negative angle face cutting edge forms a negative angle face second rake angle, and the negative angle face second rake angle is greater than the corresponding first rake angle. In this application, the “working portion” and “body portion” of the profile milling cutter have the same meaning and can be used interchangeably.

[0098] In the present application, "negative angle surface", "positive angle surface" and "side surface" are used to describe different areas of the back cutting edge of a cutting tooth. The "negative angle surface" is located in the area where the first front angle formed at the corresponding cutting edge is a negative angle, the "positive angle surface" is located in the area where the first front angle formed at the corresponding cutting edge is a positive angle, and the "side surface" is the area between the positive angle surface and the negative angle surface. The chip groove in the present application may be a spiral groove or not. The products and methods of the present application have no special restrictions on the specific structure and shape of the chip groove. For the sake of ease of understanding and explanation, the present application uses a spiral groove forming milling cutter for explanation, but those skilled in the art should understand that the specific method of the explanation is also applicable to other forms of chip grooves. The spiral of the spiral groove in the present application can be left-handed or right-handed. Generally, the positions of the negative angle surface and the positive angle surface of the cutting tooth are related to the direction of the spiral groove. When the spiral groove is left-handed, for the selected cutting tooth, the negative angle surface is the paraxial surface, that is, the surface of the cutting tooth closer to the machine tool spindle, and the positive angle surface is the distal surface, that is, the surface of the cutting tooth farther from the machine tool spindle. In the case of right-handed spiral grooves, the opposite is true. The negative angle surface is the distal surface, that is, the surface of the cutting tooth farther from the machine tool spindle, and the positive angle surface is the paraxial surface, that is, the surface of the cutting tooth closer to the machine tool spindle. Those skilled in the art understand that the division of the cutting tooth back face into negative angle surface, positive angle surface, and side surface, as well as the definition of the corresponding negative angle surface cutting edge, positive angle surface cutting edge, and side cutting edge, is only for the convenience of describing the different areas of the cutting tooth and the corresponding cutting edge area, and should not be regarded as a limitation of the present application. For example, the present application defines the side surface as the area between the positive angle surface and the negative angle surface, but should not be regarded as limiting the first rake angle of the side cutting edge to 0 degrees. According to the general understanding of those skilled in the art, the side surface is located between the paraxial surface and the distal axis surface, and the first rake angle of the corresponding side cutting edge may be either a positive angle or a negative angle, and may also gradually transition from a positive angle to a negative angle or from a negative angle to a positive angle. All examples in this application are introduced with reference to left-handed spiral grooves, but those skilled in the art should understand that making similar designs based on the provision of right-handed spiral grooves, or making similar designs on spiral grooves that include both left-handed and right-handed spiral grooves, are fully understood by those skilled in the art and do not require any excessive effort, and are also within the scope of the present application.

[0099] In the present application, the “second rake angle of the negative angle surface” refers to the second rake angle formed at any selected point of the cutting edge corresponding to the negative angle surface.

[0100] The first rake angle of the spiral groove forming milling cutter includes the cases of being greater than 0, equal to 0 and less than 0. When the first rake angle is less than 0, that is, the first rake angle at the corresponding cutting edge is a negative angle in the negative angle surface area, the milling cutter sharpness in this area is not enough, and during the milling process, the corresponding cutting edge part is subjected to greater force and severe wear, resulting in a shorter life of the milling cutter. The present application effectively solves the problem of the negative rake angle or too small rake angle of the cutting edge of the spiral groove forming milling cutter by setting a secondary chip groove extending along the direction of the negative angle surface cutting edge, forming a negative angle surface second rake angle greater than the corresponding first rake angle, so that the sharpness of the spiral groove forming milling cutter is significantly improved, the cutting resistance is reduced, the thermal damage to the workpiece surface is reduced, the cutting efficiency and cutting accuracy are greatly improved, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after long-term use, and thus the life of the milling cutter is also greatly improved. The present application defines the forming milling cutter body as a whole cemented carbide material. The various processing methods in the prior art do not make the direction of sharpness improvement distributed along the cutting edge, so that all cutting edges cannot obtain similar large rake angles, and the tool processing accuracy, processing efficiency, and processing life are poor. Milling cutters made of the same material, due to the lack of secondary chip grooves distributed along the cutting edge in existing technologies, have high cutting resistance, and the Ti alloy will produce a Ti alloy hardened layer, which can easily cause cracks in the workpiece, thus shortening the workpiece life. Furthermore, the presence of a large negative angle increases friction between the tool and the workpiece, not only producing a hardened layer but also causing tool yield, which directly affects machining accuracy and is unacceptable in high-precision machining. However, the profiled milling cutter of the present application can maintain good sharpness without the hardened layer, cracks, or tool yield.

[0101] In some embodiments, the second rake angle of the negative angle surface is greater than the first rake angle by 3 to 65 degrees, for example, 5 to 35 degrees, and for example, 3 to 35 degrees. Those skilled in the art may adjust this as needed. Generally, the smaller the first rake angle of any selected point on the negative angle surface cutting edge, the larger the second rake angle of the negative angle surface formed by providing the secondary chip groove should be, so as to achieve a sharp cutting edge.

[0102] In some embodiments, the angle of the spiral groove is the angle between the spiral direction and the main axis, and the angle of the spiral groove is between 3 and 55 degrees, for example, 15 to 55 degrees, for example, 25 to 50 degrees, for example, 15 to 50 degrees, for example, 25 to 45 degrees; the secondary chip groove also extends in the direction of the side cutting edge in the length direction, and the secondary chip groove has a groove surface close to the side cutting edge, so that the groove surface of the secondary chip groove close to the side cutting edge forms a second side rake angle, and the second side rake angle is greater than the corresponding first rake angle. Generally, the larger the angle of the spiral groove, the faster the first rake angle changes along the cutting edge, and the more obvious the change in sharpness of the milling cutter at different positions on the cutting edge. In order to enable the milling cutter cutting edge to meet the sharpness requirements as a whole, the present application further defines that the secondary chip groove also extends in the direction of the side cutting edge in the length direction, that is, the groove surface close to the negative angle cutting edge continues to extend in the direction of the side cutting edge to form a groove surface close to the side cutting edge, thereby forming a negative angle second rake angle greater than the corresponding first rake angle near the negative angle cutting edge, and forming a side second rake angle greater than the corresponding first rake angle near the side cutting edge, effectively solving the problem of negative rake angle of the spiral groove forming milling cutter cutting edge and the problem of too small cutting edge rake angle, for example, changing the negative rake angle into a positive rake angle. Further improve cutting efficiency and cutting accuracy in a larger range, and extend tool life. The extension direction of the secondary chip groove is consistent with the cutting edge. When the cutting edge is a curve, the secondary chip groove is extended in a curve. In the present application, the length direction of the secondary chip groove refers to the direction consistent with the extension direction of the secondary chip groove. Therefore, the length direction of the secondary chip groove and the extension direction of the secondary chip groove have the same meaning and can be used interchangeably.

[0103] In some embodiments, the secondary chip groove extends along the entire cutting edge, so that all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees, greater than or equal to 10 degrees and less than or equal to 35 degrees, greater than or equal to 15 degrees and less than or equal to 25 degrees, or greater than or equal to 27 degrees and less than or equal to 40 degrees. In order to make the entire cutting edge of the forming milling cutter meet the sharpness requirements, the secondary chip groove can extend along the entire cutting edge, so that the actual rake angle of any selected point on the entire cutting edge meets a specific range. For the cutting edge with a secondary chip groove, its actual rake angle is the second rake angle. Although the present application limits the secondary chip groove to extending along the entire cutting edge, for the chip edge of the spiral groove forming milling cutter, the cutting edge rake angle at different cutting edges is different. For example, the first rake angle of the cutting edge gradually increases from a too small negative angle to a positive angle along the cutting edge. During this change process, the first rake angle of part of the cutting edge is within the required actual rake angle range, and there is no need to set a secondary chip groove near this part of the cutting edge. At this time, the actual rake angle is the first rake angle. Therefore, this application defines the secondary chip groove as extending along the entire cutting edge, including the situation where a secondary chip groove is not provided in a specific area of ​​the cutting edge. Those skilled in the art can reasonably arrange the secondary chip groove based on the rake angle of different cutting edge areas, and ultimately make the actual rake angle of the entire cutting edge fall within the range defined in this application, so that the sharpness is improved along the direction of the cutting edge, while ensuring processing accuracy, improving cutting efficiency, reducing cutting resistance, and extending tool life.

[0104] In some embodiments, the width of the secondary chip groove is 0.15mm to 3mm or 3% to 30% of the milling cutter diameter. For example, the width of the secondary chip groove is 0.3mm to 2.5mm, or 0.5mm to 2mm, or 0.8mm to 1.8mm, or 1mm to 1.5mm, or the width of the secondary chip groove is 3% to 30% of the milling cutter diameter, or 5% to 25%, or 8% to 18%, or 10% to 15%. The secondary chip groove width refers to the dimension of the secondary chip groove on the rake face perpendicular to the direction of extension of the cutting edge, and the milling cutter diameter refers to the diameter of the maximum outer circle of the cutting edge rotation when the milling cutter is in operation.

[0105] In some embodiments, the depth of the secondary chip flute is 0.1 to 2 mm, or 0.3 to 1.5 mm. For example, the depth of the secondary chip flute is 0.5 to 1.2 mm, or 0.6 to 1 mm.

[0106] In some embodiments, the flute surface of the secondary chip groove near the negative angle cutting edge and / or the flute surface near the side cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a flute bottom surface, the flute bottom surface is connected to the flute surface near the negative angle cutting edge and / or the flute surface near the side cutting edge and is substantially parallel to the rake face, and the flute bottom surface is wavy. The wavy extension of the flute surface or the wavy undulation of the flute bottom surface can act as a reinforcing rib, improve the cutting edge strength without reducing the sharpness of the cutting edge, improve the durability of the cutting edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after long-term use, reduce thermal damage to the workpiece surface, and further increase the linear speed during milling. Practice has shown that when the flute surface near the cutting edge of the secondary chip groove is wavy, the tool can be processed at a higher linear speed, the performance of the tool is stable, and the accuracy of the workpiece can also be guaranteed, thereby improving the processing efficiency.

[0107] In some embodiments, the diameter of the milling cutter is 5 mm to 80 mm, such as 5 mm to 50 mm, such as 8 mm to 40 mm, or 10 mm to 30 mm.

[0108] In some embodiments, the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0109] In some embodiments, the secondary chip grooves are fabricated using a femtosecond pulse laser processing method. During femtosecond pulse laser processing, the total amount of heat provided each time is small and concentrated. Before the heat generated by processing is transferred to the workpiece, the cutting chips have already vaporized, removing a large amount of heat. In other words, the rate at which the cutting chips vaporize and remove heat is greater than the rate at which heat is transferred within the workpiece, thus preventing thermal damage to the workpiece surface. In contrast, other existing laser processing methods provide a larger amount of heat at a time, which can easily cause thermal damage to the workpiece surface.

[0110] The preparation method of the spiral groove forming milling cutter in the prior art is known to those skilled in the art, and includes the following steps: 1. Calculating the shape of the spiral groove forming milling cutter according to actual needs and selecting a suitable cemented carbide rod; 2. Starting from the cemented carbide rod, the cemented carbide rod is ground to form a blank of the spiral groove forming milling cutter; 3. A semi-finished product of the spiral groove forming milling cutter is formed by fine grinding; 4. The semi-finished product is PVD-coated to form a finished product of the spiral groove forming milling cutter.

[0111] The present application provides a method for increasing the sharpness of a spiral groove forming milling cutter, which primarily involves machining a secondary chip groove on a semi-finished product, and then subjecting the semi-finished product with the secondary chip groove to a PVD coating. Furthermore, the present application also provides a method for processing a spiral groove forming milling cutter (the spiral groove forming milling cutter being scrapped or non-scrapped), comprising optionally grinding the rake face of the spiral groove forming milling cutter, providing the spiral groove forming milling cutter with a secondary chip groove, and then subjecting the spiral groove forming milling cutter provided with the secondary chip groove to a PVD coating.

[0112] Therefore, the present application also discloses a method for increasing the sharpness of a spiral groove forming milling cutter, wherein the spiral groove forming milling cutter comprises a forming milling cutter body portion and an optional connecting portion for directly or indirectly connecting to a machine tool, at least the forming milling cutter body portion is made of a solid carbide material, the forming milling cutter body portion has a plurality of cutting edges and a plurality of main chip grooves corresponding to the cutting edges, the cutting edges each independently have a rake face, a flank face and a cutting edge, the rake face forms a first rake angle at each location of the cutting edge, the main chip groove is a spiral groove, each of the The cutting edge includes at least one cutting tooth, the back face of the cutting tooth is divided into a negative angle face, a positive angle face and a side face, thereby corresponding to three types of cutting edges, namely a negative angle face cutting edge, a positive angle face cutting edge and a side face cutting edge, and is characterized in that the method includes: forming a secondary chip groove on the front cutting edge, the secondary chip groove extending in the length direction along the direction of the negative angle face cutting edge, the secondary chip groove having a groove face close to the negative angle face cutting edge, so that the groove face of the secondary chip groove close to the negative angle face cutting edge forms a second negative angle face rake angle, and the second negative angle face rake angle is greater than the corresponding first rake angle. The present application effectively solves the problem of the negative rake angle of the cutting edge of the spiral groove forming milling cutter by providing a secondary chip groove extending in the direction of the negative angle face cutting edge to form a second negative angle face rake angle greater than the corresponding first rake angle, thereby significantly improving the sharpness of the spiral groove forming milling cutter, reducing cutting resistance, reducing thermal damage to the workpiece surface, greatly improving cutting efficiency and cutting accuracy, thereby improving processing accuracy, and enabling the tool to maintain processing accuracy even under long-term use, thereby greatly improving the life of the milling cutter. Various processing methods in the prior art do not distribute the direction of sharpness improvement along the cutting edge, so that all cutting edges cannot obtain similar large rake angles, resulting in poor tool processing accuracy, processing efficiency, and processing life.

[0113] In some embodiments, the second rake angle of the negative angle surface is greater than the first rake angle by 3 to 65 degrees, for example, 5 to 35 degrees, and for example, 3 to 35 degrees. Those skilled in the art may adjust this as needed. Generally, the smaller the first rake angle of any selected point on the negative angle surface cutting edge, the larger the second rake angle of the negative angle surface formed by providing the secondary chip groove should be, so as to achieve a sharp cutting edge.

[0114] In some embodiments, the angle of the spiral groove is the angle between the direction of the spiral and the main axis, and the angle of the spiral groove is between 3 and 55 degrees, for example, 15 to 50 degrees, for example, 25 to 45 degrees, for example, 15 to 50 degrees, for example, 25 to 45 degrees; the secondary chip groove also extends in the direction of the side cutting edge in the length direction, and the secondary chip groove has a groove surface close to the side cutting edge, so that the groove surface of the secondary chip groove close to the side cutting edge forms a second side rake angle, and the second side rake angle is greater than the corresponding first rake angle. Generally, the larger the angle of the spiral groove, the faster the first rake angle changes along the cutting edge, and the more obvious the change in sharpness of the milling cutter at different positions on the cutting edge. In order to ensure that the cutting edge of the milling cutter can meet the sharpness requirements as a whole, the present application further stipulates that the secondary chip groove also extends in the direction of the side cutting edge in the length direction, that is, the groove surface close to the negative angle cutting edge continues to extend along the direction of the side cutting edge to form a groove surface close to the side cutting edge, thereby forming a negative angle surface second rake angle greater than the corresponding first rake angle near the negative angle cutting edge, and forming a side second rake angle greater than the corresponding first rake angle near the side cutting edge, effectively solving the problem of negative rake angle of the spiral groove forming milling cutter cutting edge and the problem of too small cutting edge rake angle. Further improve cutting efficiency and cutting accuracy in a wider range, and extend tool life.

[0115] In some embodiments, the secondary chip groove extends along the entire cutting edge, so that all actual rake angles are greater than or equal to 5 degrees and less than or equal to 45 degrees, greater than or equal to 10 degrees and less than or equal to 35 degrees, greater than or equal to 15 degrees and less than or equal to 25 degrees, or greater than or equal to 27 degrees and less than or equal to 40 degrees. In order to make the entire cutting edge of the forming milling cutter meet the sharpness requirements, the secondary chip groove can extend along the entire cutting edge, so that the actual rake angle of any selected point on the entire cutting edge meets a specific range. For the cutting edge with a secondary chip groove, its actual rake angle is the second rake angle. Although the present application limits the secondary chip groove to extending along the entire cutting edge, for the chip edge of the spiral groove forming milling cutter, the cutting edge rake angle at different cutting edges is different. For example, the first rake angle of the cutting edge gradually increases from a too small negative angle to a positive angle along the cutting edge. During this change process, the first rake angle of part of the cutting edge is within the required actual rake angle range, and there is no need to set a secondary chip groove near this part of the cutting edge. At this time, the actual rake angle is the first rake angle. Therefore, this application defines the secondary chip groove as extending along the entire cutting edge, including the situation where a secondary chip groove is not provided in a specific area of ​​the cutting edge. Those skilled in the art can reasonably arrange the secondary chip groove based on the rake angle of different cutting edge areas, and ultimately make the actual rake angle of the entire cutting edge fall within the range defined in this application, so that the sharpness is improved along the direction of the cutting edge, while ensuring processing accuracy, improving cutting efficiency, reducing cutting resistance, and extending tool life.

[0116] In some embodiments, the width of the secondary chip groove is 0.15mm to 3mm or 3% to 30% of the milling cutter diameter. For example, the width of the secondary chip groove is 0.3mm to 2.5mm, or 0.5mm to 2mm, or 0.8mm to 1.8mm, or 1mm to 1.5mm, or the width of the secondary chip groove is 3% to 30% of the milling cutter diameter, or 5% to 25%, or 8% to 18%, or 10% to 15%. The secondary chip groove width refers to the dimension of the secondary chip groove on the rake face perpendicular to the direction of extension of the cutting edge, and the milling cutter diameter refers to the diameter of the maximum outer circle of the cutting edge rotation when the milling cutter is in operation.

[0117] In some embodiments, the depth of the secondary chip flute is 0.1 to 2 mm, or 0.3 to 1.5 mm. For example, the depth of the secondary chip flute is 0.5 to 1.2 mm, or 0.6 to 1 mm.

[0118] In some embodiments, the groove surface of the secondary chip groove close to the negative angle cutting edge and / or the groove surface close to the side cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, the groove bottom surface is connected to the groove surface close to the negative angle cutting edge and / or the groove surface close to the side cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy. The wavy extension of the groove surface or the wavy undulation of the groove bottom surface can act as a reinforcing rib, improve the edge strength without reducing the sharpness of the cutting edge, improve the durability of the cutting edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even under long-term use, and reduce thermal damage to the workpiece surface. It can also further increase the linear speed during milling, thereby improving processing efficiency.

[0119] In some embodiments, the diameter of the milling cutter is 5 mm to 80 mm, such as 5 mm to 50 mm, such as 8 mm to 40 mm, or 10 mm to 30 mm.

[0120] In some embodiments, the secondary chip groove is manufactured using a processing method that does not cause thermal damage, so that no thermal damage layer exists at the secondary chip groove, and the tool strength will not be degraded due to thermal damage after the secondary chip groove is provided.

[0121] In some embodiments, the secondary chip groove is prepared by a femtosecond pulse laser processing method.

[0122] The present application provides a secondary chip groove and extends the secondary chip groove along the negative angle cutting edge, or also extends along the direction of the side cutting edge, or extends along the entire cutting edge, so that the secondary chip groove forms a negative angle second rake angle greater than the corresponding first rake angle on the groove surface close to the negative angle cutting edge, forms a side second rake angle on the groove surface close to the side cutting edge, or makes all actual rake angles within a specific range, effectively solving the problem of negative rake angle or too small rake angle of the cutting edge of the spiral groove forming milling cutter, and by increasing the rake angle of the cutting edge, the cutting is made lighter, the cutting resistance is effectively reduced, the processing accuracy is higher, the tool life is longer, and the tool can maintain processing accuracy even after long-term use. The present application also further strengthens the overall strength of the milling cutter and the linear speed during processing by providing a wavy groove surface and / or a wavy groove bottom surface, thereby improving processing efficiency. The tested life of the milling cutter using the technical solution of the present application is 2-5 times that of the tool life of the prior art.

[0123] The above ranges can be used alone or in combination. The present application can be more easily understood through the following examples.

[0124] Example

[0125] Example 1

[0126] This embodiment discloses a solid carbide forming milling cutter with auxiliary chip grooves, such as Figures 1 to 6 As shown, it includes a working part 20 and a connecting part 30 for connecting to a machine tool, wherein the working part is made of cemented carbide, and the working part has four cutting edges 100 and four main chip grooves 200 corresponding to the cutting edges, and the cutting edges each independently have a front cutting face 110, a back cutting face 120 and a cutting edge 130 formed by the intersection of the front cutting face and the back cutting face, and the front cutting face forms a first rake angle of -5 degrees at each location of the cutting edge, and is characterized in that a secondary chip groove 10 is provided on the front cutting face, and the secondary chip groove extends in the length direction along the direction of the cutting edge, and the secondary chip groove has a groove surface 11 close to the cutting edge.

[0127] Figure 5 The figure shows the Figure 2 The auxiliary chip groove 10 is set on the cutting edge on the AA section in the middle, the diameter of the milling cutter is 20mm, the width of the auxiliary chip groove is 0.6mm, and the depth of the auxiliary chip groove is 0.3mm. Figure 6 for Figure 5 The partial enlarged view in the dotted frame shows the groove surface 11 of the secondary chip groove, and the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle of 25 degrees, which is greater than the corresponding first rake angle.

[0128] Example 2

[0129] This embodiment discloses an integral carbide forming milling cutter with a secondary chip groove, which is basically the same as the forming milling cutter in Example 1, with the difference that: in this embodiment, the groove surface of the secondary chip groove close to the cutting edge is wavy and extends along the direction of the cutting edge, and the secondary chip groove has a groove bottom surface 12, which is connected to the groove surface close to the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy. Figure 7 The groove surface 11 extending in a wave shape along the cutting edge direction and the groove bottom surface 12 undulating in a wave shape are shown.

[0130] The cutting tools in Examples 1 and 2 of the present application were used to test the machining of aircraft blade disks. A cutting tool without a secondary chip groove was used as a control. The material was titanium alloy, and the milling machine used a C42 milling cutter from Hammer to conduct the test machining. The results are as follows:

[0131] Table 1

[0132] Knives comparison Example 1 Example 2 Processing accuracy (mm) 0.003 0.003 0.003 Processing speed (m / s) 75 75 90 Processing life (number of workpieces) 1 4 3

[0133] As can be seen from the table above, compared to the control without auxiliary chip grooves, the solution of the present application with auxiliary chip grooves can process up to four workpieces, resulting in a longer tool life and the ability to maintain machining accuracy even after long-term use. With the wavy groove surface and groove bottom, the tool processing speed can reach 90m / s, and the number of workpieces processed reaches 3, indicating that the use of the wavy groove surface and groove bottom further enhances the overall strength of the milling cutter and the linear speed during machining, thereby improving machining efficiency.

[0134] Example 3

[0135] This embodiment discloses a solid carbide forming milling cutter with a secondary chip groove, which is a spiral groove forming milling cutter, such as Figures 8 to 14 As shown, it includes a working part 20 and a connecting part 30 for connecting to a machine tool, the working part is made of solid carbide, the working part has four cutting edges 100 and four main chip grooves 200 corresponding to the cutting edges, the cutting edges 100 each independently have a front cutting face 110, a back cutting face 120 and a cutting edge 130 formed by the intersection of the front cutting face and the back cutting face, the front cutting face forms a first rake angle at each location of the cutting edge, it is characterized in that a secondary chip groove 10 is provided on the front cutting face, the secondary chip groove extends in the length direction along the direction of the cutting edge, the secondary chip groove has a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle.

[0136] The main chip groove 200 is a spiral groove, and each cutting edge includes three cutting teeth 300. Figure 10As shown, the back cutting surface 120 of the cutting tooth is divided into a negative angle surface 121, a positive angle surface 122 and a side surface 123, which corresponds to three cutting edges, namely the negative angle cutting edge 131, the positive angle cutting edge 132 and the side cutting edge 133, and the secondary chip groove is at least arranged on the front cutting surface with a first rake angle less than 0 degrees formed at the cutting edge, that is, the secondary chip groove 10 extends in the length direction along the direction of the negative angle cutting edge 131.

[0137] The angle of the spiral groove is 25 degrees, and the angle of the spiral groove is the angle between the direction of the spiral and the main axis. Figure 10 The angle ω of the spiral groove is shown.

[0138] The secondary chip groove 10 also extends in the direction of the side cutting edge 133 in the length direction, and the secondary chip groove has a groove surface close to the side cutting edge. Figure 12 A selected point along the side cutting edge 133 (ie Figure 11 The secondary chip groove is set on the side cutting edge of the AA section. Figure 13 for Figure 12 The partially enlarged view of the portion shown in the dotted box shows the groove surface 11 close to the side cutting edge, so that the groove surface of the secondary chip groove close to the side cutting edge forms a second side rake angle, and the second side rake angle is greater than the corresponding first rake angle.

[0139] Figure 14 for Figure 11 The partial enlarged view of the cross-sectional view of the cutting edge in the dotted line frame shows that the auxiliary chip groove 10 extends in a curve on the paraxial surface and the corresponding cutting edge of the side of the three chip teeth 300, wherein the cutting edge corresponding to the paraxial surface is the negative angle cutting edge 131, and the corresponding cutting edge on the side is the side cutting edge 133. The side cutting edge includes Figure 14 The convex arc-shaped cutting edge is located at the wave crest and the concave arc-shaped cutting edge is located at the wave trough.

[0140] Figure 15 for Figure 14 BB cross-section view of the cutting tooth in the middle. Figure 14 The BB section plane in the figure is perpendicular to the section edge located on the paraxial plane. Figure 15The figure shows, by way of example, the first rake angle 1 and the second rake angle 2 at the cutting edge 130 when the secondary chip groove 10 is provided. The first rake angle 1 is a negative angle, and its value is equal to 90 degrees minus the angle between the intersection of the BB section plane (i.e., the plane perpendicular to the cutting edge at the section point) and the front and rear cutting edges at the cutting edge (marked a1 in the figure), that is, the value obtained by 90-a1, which is -15 degrees. The second rake angle 2 is 25 degrees, and its value is equal to 90 degrees minus the angle between the intersection of the BB section plane (i.e., the plane perpendicular to the cutting edge at the section point) and the groove surface of the secondary chip groove close to the cutting edge and the rear cutting edge at the cutting edge (marked a2 in the figure), that is, the value obtained by 90-a2, which is 25 degrees. Figure 15 The dotted line that forms the common edge of a1 and a2 is the intersection line of the BB section plane and the back face without the air gap design. Figure 15 The selected point edge 130 of the middle cutting edge, 25 degrees is the second rake angle of the negative angle surface, and -15 degrees is the corresponding first rake angle. The actual rake angle at this point is 25 degrees.

[0141] By setting a secondary chip groove extending along the cutting edge direction, a negative second rake angle of the surface and a second rake angle of the side surface that are greater than the corresponding first rake angle are formed, which effectively solves the problem of negative rake angle or too small rake angle of the cutting edge of the spiral groove forming milling cutter, improves cutting efficiency and cutting accuracy, thereby improving processing accuracy, and enables the tool to maintain processing accuracy even after long-term use.

[0142] The diameter of the milling cutter is 20 mm, the width of the secondary chip groove is 2 mm, and the depth of the secondary chip groove is 0.3 mm. The spiral groove forming milling cutter of the embodiment of the present application is prepared as follows: a spiral groove forming milling cutter blank is purchased from the market, and a semi-finished product of the spiral groove forming milling cutter is formed by fine grinding, and then the spiral groove forming milling cutter is provided with a secondary chip groove, and finally the semi-finished product is subjected to PVD coating treatment to form a finished product of the spiral groove forming milling cutter. The step of fine grinding to form the semi-finished product of the spiral groove forming milling cutter is completed by a grinder. The PVD coating treatment is prepared by the method of the prior art. The secondary chip groove described in the present application is prepared by femtosecond pulse laser processing and forming, for example, a precision CNC laser machine purchased from DMG Mori Seiki Co., Ltd. under the trade name LASERTEC 50Shape can be used.

[0143] Example 4

[0144] This embodiment discloses an integral carbide forming milling cutter with a secondary chip groove, which is a spiral groove forming milling cutter. It is basically the same as the forming milling cutter in Example 3, with the difference that: the secondary chip groove in this embodiment is only arranged at the negative angle edge, which is located on the near-axial surface of the tool.

[0145] Example 5

[0146] This embodiment discloses a solid carbide profile milling cutter with a secondary chip flute. This is a spiral flute profile milling cutter, which is substantially identical to the profile milling cutter of Example 3, except that the secondary chip flute in this embodiment is provided only at the negative cutting edge, located on the paraxial surface of the cutter. Furthermore, in this embodiment, the flute surface of the secondary chip flute near the negative cutting edge is wavy and extends in the direction of the cutting edge. The secondary chip flute has a flute bottom surface 12, which is connected to the flute surface near the negative cutting edge and is substantially parallel to the rake face, and the flute bottom surface is wavy and undulating. Figure 16 The figure shows a groove surface 11 extending in a wave shape along the direction of the cutting edge at the negative angle surface, and a groove bottom surface 12 undulating in a wave shape.

[0147] Example 6

[0148] This embodiment discloses an integral carbide forming milling cutter with a secondary chip groove, which is a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Example 3, with the difference that: in this embodiment, the groove surface of the secondary chip groove close to the negative angle edge and the groove surface close to the side edge are wavy and extend along the direction of the edge, or, the secondary chip groove has a groove bottom surface, and the groove bottom surface is connected to the groove surface close to the negative angle edge and the groove surface close to the side edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

[0149] Example 7

[0150] like Figure 17 As shown, this embodiment discloses an integral carbide forming milling cutter with a secondary chip groove, which is a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Example 3, with the difference that: the angle of the spiral groove in this embodiment is 20 degrees, and the secondary chip groove extends along the entire cutting edge, so that all actual front angles are 25 degrees.

[0151] Example 8

[0152] This embodiment discloses an integral carbide forming milling cutter with a secondary chip groove, which is a spiral groove forming milling cutter. It is basically the same as the forming milling cutter in Example 3, with the difference that: the angle of the spiral groove in this embodiment is 25 degrees, and the secondary chip groove extends along the entire cutting edge, so that all actual front angles are 27 degrees.

[0153] The cutting tools in Examples 3 to 8 of the present application were used to test the machining of aircraft blade disks. A cutting tool without a secondary chip groove was used as a control. The material was titanium alloy, and the milling machine used a C42 milling cutter from Hammer to conduct the test machining. The results are as follows:

[0154] Table 2

[0155]

[0156] The applicant unexpectedly discovered that, compared to a control without a secondary chip groove, the profiled milling cutter of the present application can process more workpieces. However, a milling cutter of the same material, without a secondary chip groove, will produce a Ti alloy hardened layer when processing the second workpiece, resulting in cracks, which affects the life of the engine blade disc. In addition, due to the presence of a large negative angle, the friction between the tool and the workpiece increases. In addition to producing a hardened layer, it also causes a tool yield phenomenon, which directly affects the processing accuracy, which is unacceptable in high-precision processing. However, the profiled milling cutter of the present application can still maintain good sharpness even after producing 3-5 workpieces, and does not produce a hardened layer, cracks, or tool yield phenomenon. When the groove surface near the cutting edge of the secondary chip groove is formed into a wavy shape, the tool can be processed at a higher linear speed of 90 meters per second, the performance of the tool is stable, and the accuracy of the workpiece can also be guaranteed, which improves processing efficiency.

[0157] The foregoing description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. The scope of protection of the present disclosure is determined by the appended claims.

Claims

1. A solid carbide forming milling cutter with secondary chip grooves, comprising a working part and an optional connecting part for directly or indirectly connecting to a machine tool, wherein at least the working part is made of carbide, the working part has a plurality of cutting edges and a plurality of primary chip grooves corresponding to the cutting edges, the cutting edges each independently have a rake face, a flank face and a cutting edge formed by the intersection of the rake face and the flank face, the rake face forms a first rake angle at each location of the cutting edge, characterized in that A secondary chip groove is provided on the front cutting edge, the secondary chip groove extends in the length direction along the direction of the cutting edge, and the secondary chip groove has a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle. The first rake angle is always 0 degree.

2. The solid carbide forming milling cutter according to claim 1, characterized in that: The second rake angle is greater than the corresponding first rake angle by 3 to 65 degrees, such as 10 to 60 degrees, such as 20 to 40 degrees.

3. The solid carbide forming milling cutter according to claim 2, characterized in that: The second rake angle is greater than 7 degrees, greater than 10 degrees, greater than 15 degrees, or greater than 35 degrees.

4. The solid carbide forming milling cutter according to claim 1, characterized in that: The width of the secondary chip groove is 0.15 mm to 3 mm or 3% to 30% of the diameter of the milling cutter.

5. The solid carbide forming milling cutter according to claim 1, characterized in that: The depth of the secondary chip groove is 0.1 to 1.5 mm.

6. The solid carbide forming milling cutter according to claim 1, characterized in that: The groove surface of the secondary chip groove close to the cutting edge is wavy and extends in the direction of the cutting edge, or the secondary chip groove has a groove bottom surface, which is connected to the groove surface close to the cutting edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy.

7. The solid carbide forming milling cutter according to claim 1, characterized in that: The diameter of the milling cutter is 5 mm to 50 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

8. A method for increasing the sharpness of a solid carbide forming milling cutter, The solid carbide forming milling cutter comprises a working part and an optional connecting part for directly or indirectly connecting with a machine tool, wherein at least the working part is made of carbide, the working part has a plurality of cutting edges and a plurality of main chip grooves corresponding to the cutting edges, the cutting edges each independently have a rake face, a flank face and a cutting edge formed by the intersection of the rake face and the flank face, the rake face forms a first rake angle at each location of the cutting edge, The method comprises: A secondary chip groove is formed on the front cutting edge, the secondary chip groove extends in the length direction along the direction of the cutting edge, and the secondary chip groove has a groove surface close to the cutting edge, so that the groove surface of the secondary chip groove close to the cutting edge forms a second rake angle, and the second rake angle is greater than the corresponding first rake angle. The first rake angle is always 0 degree.

9. The method according to claim 8, characterized in that The secondary chip groove is prepared by a processing method that does not cause thermal damage.

10. The method according to claim 8, characterized in that The auxiliary chip groove is prepared by a femtosecond pulse laser processing method.

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