Spiral groove forming milling cutter

Abstract

The invention provides a spiral groove forming milling cutter which is provided with a plurality of cutting edges and a plurality of main chip flutes corresponding to the cutting edges, each cutting edge is independently provided with a front cutter face, a rear cutter face and a cutting edge, the front cutter face forms a first front angle at each position of the cutting edge, the main chip flutes are spiral grooves, and the rear cutter face forms a second front angle at each position of the cutting edge. An auxiliary chip containing groove is formed in the front cutter face, the auxiliary chip containing groove extends in the length direction in the negative angle face cutting edge direction, the auxiliary chip containing groove is provided with a groove face close to the negative angle face cutting edge, and therefore the groove face, close to the negative angle face cutting edge, of the auxiliary chip containing groove forms a second negative angle face front angle. And the second front angle of the negative angle surface is larger than the corresponding first front angle. The second rake angle is formed by arranging the auxiliary chip flutes, the problem that the negative rake angle or the rake angle of the cutting edge of the spiral groove forming milling cutter is too small can be effectively solved, the negative rake angle is changed into the positive rake 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, and in particular to a spiral groove forming milling cutter and a method for increasing the sharpness of the spiral groove forming milling cutter. Background Art

[0002] Milling cutter is a widely used multi-tooth multi-edge rotary tool. During milling, the milling cutter rotates around its axis as the main motion, and the workpiece performs feed motion. Milling cutters are usually used for high-speed cutting, so they have great impact and vibration during processing. Since the milling cutter is a multi-edge tool, the milling speed is high and there is no idle stroke, so it is a highly efficient cutting method. Forming milling cutter is a type of milling cutter, and its cutting edge profile is designed and calculated according to the shape of the forming surface of the workpiece. Forming milling cutters can not only process planes, grooves, steps, but also threads, splines, gears and other forming surfaces. Forming milling cutters in the prior art have the problem of not being able to take into account both cutting speed and structural strength. In particular, the high-precision blades, blades and impellers of aircraft engine parts and steam turbine parts require extremely high performance of the tool. The tools in the prior art cannot meet the requirements in terms of processing accuracy, cutting speed, service life, etc., which has restricted the production progress of these projects. In the prior art, tools made of high-speed steel and cemented carbide are usually used. High-speed steel has good toughness and the cutting edge is easier to sharpen. However, due to the characteristics of high-speed steel materials, it is difficult to achieve high-speed processing, and the service life of high-speed steel milling cutters is short. Cemented carbide is resistant to high temperatures and suitable for high-speed processing. However, due to the existing tool manufacturing process, it cannot meet the sharp and large rake angle requirements of the cutting edge required for the forming milling cutter. The tool processing accuracy is poor, the cutting efficiency is low, and the service life is short, which cannot meet the needs of the industry. There is an urgent need to improve the processing efficiency, processing accuracy, and processing life of the tool. Summary of the invention

[0003] The present application provides a spiral groove forming milling cutter and a method for increasing the sharpness of the spiral groove forming milling cutter, including the following implementation methods:

[0004] Embodiment 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 rake angle at each 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 a secondary chip groove is arranged 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.

[0005] Embodiment 2. The spiral groove forming milling cutter according to embodiment 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, such as 5 degrees to 35 degrees, such as 3 degrees to 35 degrees.

[0006] Embodiment 3. The spiral groove forming milling cutter according to embodiment 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.

[0007] Embodiment 4. The spiral groove forming milling cutter according to embodiment 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 to less than or equal to 45 degrees, greater than or equal to 10 degrees to less than or equal to 35 degrees, greater than or equal to 15 degrees to less than or equal to 25 degrees, or greater than or equal to 27 degrees to less than or equal to 40 degrees.

[0008] Embodiment 5. The spiral groove 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 spiral groove forming milling cutter according to embodiment 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.

[0010] Embodiment 7. The spiral groove forming milling cutter according to embodiment 1 is characterized in that the groove surface of the secondary chip groove close to the negative angle surface 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, which is connected to the groove surface close to the negative angle surface 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.

[0011] Embodiment 8. The spiral groove forming milling cutter according to embodiment 1 is characterized in that 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, 10 mm to 30 mm.

[0012] Embodiment 9. The spiral groove 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 spiral groove 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 spiral groove forming milling cutter,

[0015] The spiral groove forming milling cutter 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 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 comprises at least one cutting tooth, the flank 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,

[0016] The method includes: forming a secondary chip groove on the front cutting edge, wherein the secondary chip groove extends in the length direction along the direction of the negative angle surface edge, and the secondary chip groove has a groove surface close to the negative angle surface edge, so that the groove surface of the secondary chip groove close to the negative angle surface 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.

[0017] Embodiment 12. The method according to embodiment 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.

[0018] Embodiment 13. The method according to embodiment 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 40 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.

[0019] Embodiment 14. The method according to embodiment 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 25 degrees and less than or equal to 40 degrees.

[0020] Embodiment 15. The method according to embodiment 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 diameter of the milling cutter.

[0021] Embodiment 16. The method according to embodiment 11, characterized in that the depth of the secondary chip groove is 0.1 to 2 mm, or 0.3 to 1.5 mm.

[0022] Embodiment 17. The method according to embodiment 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 in 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.

[0023] Embodiment 18. The method according to embodiment 11 is characterized in that the diameter of the milling cutter is 5 mm to 80 mm, for example, 5 mm to 50 mm, for example, 8 mm to 40 mm, 10 mm to 30 mm.

[0024] 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.

[0025] 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.

[0026] The present application sets a secondary chip groove and makes the secondary chip groove extend along the negative angle surface edge, or also extend along the direction of the side edge, or extend along the entire edge, so that the groove surface of the secondary chip groove close to the negative angle surface edge forms a negative angle surface second rake angle greater than the corresponding first rake angle, forms a side second rake angle on the groove surface close to the side 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 face 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 the 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 setting a wavy extending groove surface and / or a wavy undulating groove bottom surface, thereby improving the processing efficiency. The test 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

[0027] 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 in the following description only relate to some embodiments of the present disclosure, but are not limitations of the present disclosure.

[0028] Figure 1 A three-dimensional diagram of a spiral groove forming milling cutter;

[0029] Figure 2 A schematic diagram of a main body of a spiral groove forming milling cutter;

[0030] Figure 3 This is the front view of the main body of the spiral groove forming milling cutter;

[0031] Figure 4 It is a partial cross-sectional view of the spiral groove forming milling cutter;

[0032] Figure 5 for Figure 4 AA section view of the spiral groove forming milling cutter;

[0033] Figure 6 for Figure 5 The partially enlarged schematic diagram in the dotted box;

[0034] Figure 7 for Figure 4 The partially enlarged schematic diagram in the dashed box;

[0035] Figure 8 for Figure 7 BB section view of the cutting teeth of the spiral groove forming milling cutter;

[0036] Fig. 9 A schematic diagram of providing a wavy groove surface and a groove bottom in Example 3;

[0037] Fig.10 Schematic diagram of the main body of the spiral groove forming milling cutter of Example 5;

[0038] Fig.11 It is a schematic diagram for explaining that “the front cutting surface is formed by a radius perpendicularly passing through the axis of the forming milling cutter”.

[0039] Description of the drawings: 10 - secondary chip groove, 11 - groove surface, 12 - groove bottom surface, 20 - 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 surface, 130 - cutting edge, 131 - negative angle surface cutting edge, 132 - positive angle surface cutting edge, 133 - side cutting edge, 200 - main chip groove, 300 - cutting tooth. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the 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.

[0041] The present application discloses 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 integral hard alloy, the forming milling cutter body 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 front cutting face, a back cutting face and a cutting edge, the front cutting 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 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 a secondary chip groove is arranged 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.

[0042] In some embodiments, the front cutting face is formed by a radius that passes perpendicularly through the axis of the forming milling cutter. In the present application, the expression "the front cutting face is formed by a radius that passes perpendicularly through the axis of the forming milling cutter" means that a perpendicular line drawn from any point of the cutting edge perpendicular to the axis of the forming milling cutter falls on the front cutting face. Fig.11As shown in the figure, the points shown in the figure are the points on the cutting edge and the front cutting face, and the inclined straight line is the axis of the forming milling cutter, wherein, a vertical line perpendicular to the axis of the forming milling cutter is drawn from any point of the cutting edge, and these vertical lines constitute the front cutting face, or in other words, these vertical lines all fall into the front cutting face. Such a design makes the position of the cutting edge on the vertical line, and the scaling of the cutting edge position is the scaling amount of the radius at that place, which can effectively ensure the accuracy of the tool contour line. In some embodiments, the accuracy of the tool itself can reach 0.002-0.003mm, that is, 2-3 microns. This is because the sharpness of the tool in this application does not entirely depend on the setting of the front cutting face. After setting the precise front cutting face, the sharpness of the tool can also be improved by the auxiliary chip groove. The precise front cutting face is not only easy to manufacture, but also can ensure the accuracy of the tool contour line, which is related to the accuracy of the workpiece being processed. At the same time, the auxiliary chip groove is used to improve the sharpness, so that both accuracy and sharpness are ensured. However, in the prior art, by grinding the entire front cutting edge into a sharper acute angle, it is actually impossible to make all the front angles acute, and such grinding causes the perpendicular line from the contour line of the tool edge to the axis to not be on the front cutting edge, which not only makes the contour line more complicated and the processing more complicated, but more seriously, makes the control of accuracy more difficult, easily deteriorates the accuracy of the tool and the workpiece after processing, and does not comprehensively improve the sharpness.

[0043] In this application, a milling cutter used for machining a shaped surface and having a cutting edge profile designed according to the workpiece profile is referred to as a shaped milling cutter.

[0044] The "first rake angle" in this application refers to the value obtained by subtracting the angle between the front blade face and the back blade face without a clearance design from 90 degrees. The larger the value of the first rake angle, the sharper the cutting edge. A plane perpendicular to the cutting edge is drawn at the cutting edge. The angle between the plane and the intersection of the front blade face and the back blade face at the cutting edge is the angle between the front blade face and the back blade face without a clearance design.

[0045] The "second rake angle" in this application refers to the value obtained by subtracting the angle between the groove surface of the secondary chip groove near the cutting edge and the back cutting edge when there is no air avoidance design from 90 degrees. A plane perpendicular to the cutting edge is made at the cutting edge where the secondary chip groove is provided. The angle between the intersection of the plane and the groove surface of the secondary chip groove near the cutting edge and the back cutting edge at the cutting edge is the angle between the groove surface of the secondary chip groove near the cutting edge and the back cutting edge when there is no air avoidance 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.

[0046] 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 spiral of the spiral groove in the present application can be left-handed or right-handed. Usually, 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. When the spiral groove is right-handed, it is just the opposite. 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 edge, positive angle surface edge, and side edge, is only for the convenience of describing the different areas of the cutting tooth and the corresponding 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 it should not be regarded as limiting the first rake angle of the side edge to 0 degrees. According to the common understanding of those skilled in the art, the side surface is located between the proximal axis surface and the distal axis surface, and the first rake angle of the corresponding side edge may be either a positive angle or a negative angle, and may gradually transition from a positive angle to a negative angle or from a negative angle to a positive angle. All examples of the present application are introduced with a left-handed spiral groove, but those skilled in the art should understand that making a similar design on the basis of setting a right-handed spiral groove, or making a similar design on a spiral groove that includes both left-handed and right-handed, is fully understood by those skilled in the art and does not require any excessive labor, and is also within the scope of the present application.

[0047] 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.

[0048] 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 set 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.

[0049] 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 cutting edge direction of the negative angle surface to form 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, and the processing accuracy is improved, so that the tool can maintain the processing accuracy even after long-term use, so the life of the milling cutter is also greatly improved. The present application defines the forming milling cutter body as a whole carbide material. The various processing methods in the prior art do not make the direction of improving sharpness 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. For milling cutters made of the same material, since there is no secondary chip groove distributed along the cutting edge in the prior art, the cutting resistance is large, and the Ti alloy will produce a Ti alloy hardened layer, which is easy to cause cracks in the workpiece, thus affecting the life of the workpiece. In addition, due to the presence of a large negative angle, the friction between the tool and the workpiece increases, and in addition to the hardened layer, the tool will also give way, which directly affects the processing accuracy, which is unacceptable in high-precision processing. However, the shaped milling cutter of the present application can maintain good sharpness, and there will be no hardened layer, cracks, and tool giving way.

[0050] The cemented carbide in this application 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 800-1000°C, and the allowed cutting speed is about 4-10 times that of high-speed steel. The hardness is very high, reaching (89-91) HRA, and some are as high as 93HRA; but its bending strength is 1.1-1.5GPa, which is only half of that of high-speed steel; the impact toughness is 0.04MJ / m 2About, 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 complicated blade shapes. The cemented carbide described in the present 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 carbide, or TiC-based cemented carbide, fine-grained ultrafine-grained cemented carbide, steel-bonded cemented carbide, coated cemented carbide, etc.

[0051] In some embodiments, the second rake angle of the negative angle surface is 3 to 65 degrees greater than the first rake angle, such as 5 to 35 degrees, such as 3 to 35 degrees. Those skilled in the art can make adjustments as needed. Generally, the smaller the first rake angle of any selected point of the negative angle surface cutting edge, the larger the second rake angle of the negative angle surface formed by setting the secondary chip groove should be, so as to achieve the effect of a sharp cutting edge.

[0052] 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, such as 15 to 55 degrees, such as 25 to 50 degrees, such as 15 to 50 degrees, such as 25 to 45 degrees; the secondary chip groove also extends in the direction of the side edge in the length direction, and the secondary chip groove has a groove surface close to the side edge, so that the groove surface of the secondary chip groove close to the side 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 sharpness change of the milling cutter at different positions of the cutting edge. In order to make the milling cutter cutting edge 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 surface 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 surface 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, so 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.

[0053] 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 stipulates that the secondary chip groove extends along the entire cutting edge, for the chip edge of the spiral groove forming milling cutter, the cutting edge rake angles at different cutting edges are 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, 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 the part of the cutting edge. At this time, the actual rake angle is the first rake angle. Therefore, the present application defines that the secondary chip groove extends along the entire cutting edge, including the case where the secondary chip groove is not provided in a specific area of ​​the cutting edge. 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 the present application, so that the sharpness is improved along the direction of the cutting edge distribution, while ensuring the processing accuracy, improving the cutting efficiency, reducing the cutting resistance, and extending the tool life.

[0054] 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 extension direction 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 working.

[0055] In some embodiments, the depth of the secondary chip groove is 0.1 to 2 mm, or 0.3 to 1.5 mm. For example, the depth of the secondary chip groove is 0.5 to 1.2 mm, or 0.6 to 1 mm.

[0056] In some embodiments, the groove surface of the secondary chip groove near the negative angle edge and / or the groove surface near the side edge is wavy and extends in 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 near the negative angle edge and / or the groove surface near the side edge and is basically parallel to the rake face, 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 edge strength and durability of the edge without reducing the sharpness of the edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after long-term use, reduce the thermal damage of the workpiece surface, and further improve the linear speed during milling. Practice shows that when the groove surface near the 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.

[0057] 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, 10 mm to 30 mm.

[0058] In some embodiments, the secondary chip groove is prepared by a processing method that does not cause thermal damage.

[0059] In some embodiments, the secondary chip groove is prepared by 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 the processing is transferred to the inside of the workpiece, the cutting chips have already vaporized and taken away a large amount of heat. That is, the speed at which the cutting chips vaporize and take away heat is greater than the speed at which the heat is transferred inside the workpiece, so that the surface of the workpiece is not thermally damaged. However, using other laser processing methods in the prior art, the heat provided at one time is large, which is easy to cause thermal damage to the surface of the workpiece.

[0060] The preparation method of the spiral groove forming milling cutter in the prior art is known to those skilled in the art, and comprises 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. forming a semi-finished product of the spiral groove forming milling cutter by fine grinding; 4. performing PVD coating on the semi-finished product to form a finished product of the spiral groove forming milling cutter.

[0061] A method for increasing the sharpness of a spiral groove forming milling cutter in the present application mainly comprises machining a secondary chip groove on the basis of the semi-finished product, and then performing a PVD coating treatment on the semi-finished product with the secondary chip groove. In addition, the present application also provides a method for treating a spiral groove forming milling cutter (the spiral groove forming milling cutter is waste or non-waste), comprising optionally grinding the front cutting face of the spiral groove forming milling cutter, setting a secondary chip groove on the spiral groove forming milling cutter, and then performing a PVD coating treatment on the spiral groove forming milling cutter provided with the secondary chip groove.

[0062] 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 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 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, and each of the The cutting edge comprises 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, so as to correspond 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 the method comprises: forming a secondary chip groove on the front face, 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 negative angle face second rake angle, and the negative angle face second 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 negative angle face 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 machining accuracy, so that the tool can maintain the machining accuracy even after long-term use, and thus the life of the milling cutter is also greatly improved. Various processing methods in the prior art do not make the direction of improving sharpness 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.

[0063] In some embodiments, the second rake angle of the negative angle surface is 3 to 65 degrees greater than the first rake angle, such as 5 to 35 degrees, such as 3 to 35 degrees. Those skilled in the art can make adjustments as needed. Generally, the smaller the first rake angle of any selected point of the negative angle surface cutting edge, the larger the second rake angle of the negative angle surface formed by setting the secondary chip groove should be, so as to achieve the effect of a sharp cutting edge.

[0064] 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, such as 15 to 50 degrees, such as 25 to 45 degrees, such as 15 to 50 degrees, such as 25 to 45 degrees; the secondary chip groove also extends in the direction of the side edge in the length direction, and the secondary chip groove has a groove surface close to the side edge, so that the groove surface of the secondary chip groove close to the side 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 sharpness change of the milling cutter at different positions of the cutting edge. In order to make the milling cutter cutting edge 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 edge in the length direction, that is, the groove surface close to the negative angle surface edge continues to extend along the direction of the side edge edge to form a groove surface close to the side edge edge, thereby forming a negative angle surface second rake angle greater than the corresponding first rake angle near the negative angle surface edge, and forming a side second rake angle greater than the corresponding first rake angle near the side edge edge, effectively solving the problem of negative rake angle of the spiral groove forming milling cutter cutting edge and the problem of too small rake angle of the cutting edge. Further improve cutting efficiency and cutting accuracy in a wider range, and extend tool life.

[0065] 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 stipulates that the secondary chip groove extends along the entire cutting edge, for the chip edge of the spiral groove forming milling cutter, the cutting edge rake angles at different cutting edges are 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, 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 the part of the cutting edge. At this time, the actual rake angle is the first rake angle. Therefore, the present application defines that the secondary chip groove extends along the entire cutting edge, including the case where the secondary chip groove is not provided in a specific area of ​​the cutting edge. 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 the present application, so that the sharpness is improved along the direction of the cutting edge distribution, while ensuring the processing accuracy, improving the cutting efficiency, reducing the cutting resistance, and extending the tool life.

[0066] 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 extension direction 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 working.

[0067] In some embodiments, the depth of the secondary chip groove is 0.1 to 2 mm, or 0.3 to 1.5 mm. For example, the depth of the secondary chip groove is 0.5 to 1.2 mm, or 0.6 to 1 mm.

[0068] In some embodiments, 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 in 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. The wavy extension of the groove surface or the wavy undulation of the groove bottom surface can play the role of reinforcing ribs, improve the edge strength without reducing the sharpness of the edge, and improve the durability of the edge, thereby improving the processing accuracy, so that the tool can maintain the processing accuracy even after 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.

[0069] 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, 10 mm to 30 mm.

[0070] In some embodiments, the secondary chip groove is prepared by a processing method that does not cause thermal damage, so that there is no thermal damage layer at the secondary chip groove, and the tool strength will not be deteriorated due to thermal damage after the secondary chip groove is provided.

[0071] 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 at the secondary chip groove, 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 this 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 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 high 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 machining. 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 life of the tool is increased by 2-5 times, achieving high-precision, high-flexibility and high-efficiency machining.

[0072] The above ranges can be used alone or in combination. The present application can be more easily understood through the following examples.

[0073] Example

[0074] Example 1

[0075] This embodiment discloses a spiral groove forming milling cutter, such as Figures 1 to 8 As shown, it comprises a forming milling cutter body part 20 and a connecting part 30 for directly connecting to a machine tool, the forming milling cutter body part is made of solid carbide, the forming milling cutter body 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 rake face 110, a flank face 120 and a cutting edge 130, the rake face forms a first rake angle at each location of the cutting edge, the main chip groove 200 is a spiral groove, and each of the cutting edges comprises three cutting teeth 300, as shown in FIG. Figure 3As shown, the back cutting edge 120 of the cutting tooth is divided into a negative angle surface 121, a positive angle surface 122 and a side surface 123, corresponding to three cutting edges, namely a negative angle surface cutting edge 131, a positive angle surface cutting edge 132 and a side cutting edge 133, and is characterized in that a secondary chip groove 10 is arranged 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 131, and 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 negative angle second rake angle, and the negative angle second rake angle is greater than the corresponding first rake angle.

[0076] 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 3 The angle ω of the spiral groove is shown.

[0077] 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 5 A selected point along the side cutting edge 133 (i.e. Figure 4 The secondary chip groove is set on the side cutting edge of the AA section. Figure 6 for Figure 5 The partially enlarged view of the portion shown in the dotted frame 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.

[0078] Figure 7 for Figure 4 The partial enlarged view of the cross-sectional view at the cutting edge in the middle dashed frame shows that the secondary chip groove 10 extends in a curve on the paraxial surface and the corresponding cutting edges on the side of the three chip teeth 300, wherein the corresponding cutting edge on the paraxial surface is the negative angle cutting edge 131, and the corresponding cutting edge on the side is the side cutting edge 133, and the side cutting edge includes Figure 7 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.

[0079] Figure 8 for Figure 7 BB section view of the cutting tooth in the middle. Figure 7 The BB section plane in is perpendicular to the section edge located on the paraxial plane. Figure 8The first rake angle 1 and the second rake angle 2 at the cutting edge 130 are exemplarily marked in the case where 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 BB section plane (i.e., the plane perpendicular to the cutting edge at the section view point) and the intersection of the front cutting edge and the back cutting edge 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 BB section plane (i.e., the plane perpendicular to the cutting edge at the section view point) and the intersection of the groove surface and the back cutting edge of the secondary chip groove near the cutting edge at the cutting edge (marked a2 in the figure), that is, the value obtained by 90-a2, which is 25 degrees. Figure 8 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 clearance design. Figure 8 At the selected point edge 130 of the middle cutting edge, -15 degrees is the second rake angle of the negative angle surface, and 25 degrees is the corresponding first rake angle. The actual rake angle at this point is 25 degrees.

[0080] By providing a secondary chip groove extending along the cutting edge direction, a negative surface second rake angle and a side second rake angle 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 machining accuracy and enabling the tool to maintain machining accuracy even after long-term use.

[0081] 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, 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 molding, 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.

[0082] Example 2

[0083] This embodiment discloses a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Example 1, except 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.

[0084] Example 3

[0085] This embodiment discloses a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Embodiment 1, except that: the secondary chip groove in this embodiment is only provided at the negative angle surface edge, which is located on the paraxial surface of the tool. In this embodiment, the groove surface of the secondary chip groove close to the negative angle surface edge is wavy and extends along the direction of the edge, and the secondary chip groove has a groove bottom surface 12, which is connected to the groove surface close to the negative angle surface edge and is basically parallel to the front cutting edge, and the groove bottom surface is wavy. Fig. 9 The figure shows a groove surface 11 extending in a wave shape along the edge direction and a groove bottom surface 12 undulating in a wave shape at the negative angle edge.

[0086] Example 4

[0087] The present embodiment discloses a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Embodiment 1, with the difference that: in the present embodiment, the groove surface of the secondary chip groove close to the negative angle surface cutting edge and the groove surface close to the side cutting edge are wavy and extend along the cutting edge direction, 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 surface cutting edge and 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.

[0088] Example 5

[0089] like Fig.10 As shown, this embodiment discloses a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Example 1, 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.

[0090] Example 6

[0091] This embodiment discloses a spiral groove forming milling cutter, which is basically the same as the forming milling cutter in Example 1, except 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.

[0092] A tool without a secondary chip groove was used as a control and the tool in Examples 1 to 6 of the present application was used to perform an aircraft blade processing test. The material was titanium alloy, and the milling machine used a C42 milling cutter from Hammer Company for trial processing. The results are as follows:

[0093] Table 1

[0094]

[0095] The applicant unexpectedly found that, compared with the profiled milling cutter without the secondary chip groove, the profiled milling cutter of the present application can process more workpieces, while the milling cutter of the same material, due to the absence of the secondary chip groove, will produce a Ti alloy hardened layer when processing the second workpiece, thereby causing cracks, thereby affecting the life of the engine blade disk, and due to the presence of a large negative angle, the friction between the tool and the workpiece increases, in addition to the hardened layer, the tool will also produce a phenomenon of tool yielding, which directly affects the processing accuracy, which is unacceptable in high-precision processing. Even after producing 3-5 workpieces, the profiled milling cutter of the present application can still maintain good sharpness, and no hardened layer, cracks and tool yielding will occur. When the groove surface of the secondary chip groove close to the cutting edge 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 the processing efficiency.

[0096] The above description is merely an exemplary embodiment of the present disclosure and is not intended to limit the protection scope of the present disclosure. The protection scope of the present disclosure is determined by the appended claims.

Claims

1. A spiral groove forming milling cutter, comprising 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 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 comprises at least one cutting tooth, the flank 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 The front cutting edge is formed by a radius that passes vertically through the axis of the forming milling cutter. A secondary chip groove is arranged on the front cutting edge. 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. The second front angle of the negative angle surface is greater than the corresponding first front angle, and the actual front angle of the negative angle surface cutting edge is the second front angle of the negative angle surface.

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

3. The spiral groove forming milling cutter according to claim 1, 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.

4. The spiral groove forming milling cutter according to claim 2, 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.

5. The spiral groove 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.

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

7. The spiral groove forming milling cutter according to claim 1, 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 in 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.

8. The spiral groove forming milling cutter according to claim 1, characterized in that: The diameter of the milling cutter is 5 mm to 80 mm, or 8 mm to 40 mm, or 10 mm to 30 mm.

9. A method for increasing the sharpness of a spiral groove forming milling cutter, The spiral groove forming milling cutter 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 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 comprises at least one cutting tooth, the flank 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, The method includes: making the front cutting edge formed by a radius that passes perpendicularly through the axis of the forming milling cutter, 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 surface edge, the secondary chip groove having a groove surface close to the negative angle surface edge, so that the groove surface of the secondary chip groove close to the negative angle surface 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, thereby forming a spiral groove forming milling cutter as described in any one of claims 1 to 8.

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

11. The method according to claim 9, characterized in that The auxiliary chip groove is prepared by a femtosecond pulse laser processing method.

Images