Cutting tool

Abstract

The application belongs to the technical field of cutting machining, and discloses a cutting tool, which comprises a cutting section, the cutting section has oppositely arranged first and second ends, the first end is provided with at least two profile cutting edges which are arranged at equal intervals along the circumference of the first end, and a limiting cutting edge corresponding to each profile cutting edge, the limiting cutting edge is connected to one end of the corresponding profile cutting edge close to the second end, and the limiting cutting edge extends along the radial direction of the cutting section. Through the above arrangement, the cutting tool can meet the machining requirements of multi-step blind holes, and improve the machining precision and operation efficiency.

Description

Technical Field

[0001] This invention relates to the field of cutting technology, and more particularly to a cutting tool. Background Technology

[0002] In the powder metallurgy industry, products with multiple stepped blind holes (such as cylindrical holes, conical holes, and spherical holes) are widely used, and the processing of these blind holes is a key production step. Because the dense sintered body after high-temperature sintering has high hardness, blind holes cannot be obtained through machining methods such as drilling with cutting tools or grinding with abrasive wheels. Electrical discharge machining (EDM) is not only inefficient and costly, but also requires materials with good electrical conductivity, making it difficult to guarantee the machining accuracy of the blind holes. Therefore, the industry generally first forms a blank without blind holes, or pre-sintersects the blank at low temperature to obtain a pre-sintered blank with a certain strength. Since the internal particles of the blank and the pre-sintered blank are only mechanically interlocked or have a small amount of weak metallurgical bonding, it is relatively easy to drill to obtain multi-step blind holes with the required dimensions. Finally, the processed blank is sintered at high temperature to obtain a dense product with stepped blind holes.

[0003] However, existing multi-step blind hole machining still has the following problems: First, because multi-step blind holes include various hole types (such as cylindrical holes, conical holes, and spherical holes), multiple tools of different shapes are required for step-by-step machining, or frequent tool changes are required on a single machine tool. This not only leads to frequent adjustments of the machining datum (tool setting), significantly reducing machining efficiency, but also makes it difficult to ensure the consistency of the machining depth accuracy of each step of the blind hole. Especially when the dimensional accuracy of the pre-sintered blank itself is poor, the difference in blank size will directly cause the machining datum to shift, further aggravating the fluctuation of the blind hole depth. Second, in order to improve the datum shift problem, operators generally first perform "regularization" machining on the surface to be machined on the pre-sintered blank to unify the total height of the blank, or use a probe to test the position coordinates of the surface to be machined online to adjust the starting position of the tool. However, "regularization" machining requires additional tools or secondary clamping, which increases the risk of machining defects, increases costs, and reduces machining efficiency. Moreover, due to the softness of the pre-sintered blank and the unevenness of the end face, the probe has insufficient testing accuracy, thus failing to effectively guarantee the consistency of the blind hole machining depth.

[0004] Therefore, there is an urgent need for a cutting tool to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a cutting tool that can adapt to the machining requirements of multi-step blind holes, thereby improving machining accuracy and work efficiency.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A cutting tool includes a cutting section having a first end and a second end disposed opposite to each other.

[0008] The first end is provided with at least two forming cutting edges that are equally spaced along its circumference, and a limiting cutting edge that corresponds to each of the forming cutting edges;

[0009] The limiting cutting edge is connected to the end of the corresponding forming cutting edge near the second end, and the limiting cutting edge extends radially along the cutting segment.

[0010] Optionally, the limiting cutting edge includes a plurality of limiting sub-cutting edges spaced apart along its own extension direction. A first cutting groove is formed between two adjacent limiting sub-cutting edges in the same limiting cutting edge. Among two adjacent limiting cutting edges distributed circumferentially along the cutting segment, the first cutting groove on one limiting cutting edge is complementary to the limiting sub-cutting edge of the other limiting cutting edge. Along the radial direction of the cutting segment, the distance between the inner wall of the first cutting groove and the central axis of the cutting segment is D1. The distance between the two side walls of the limiting sub-cutting edge corresponding to the first cutting groove and the central axis of the cutting segment is a minimum distance L1 and a maximum distance L2, respectively, where L1 < D1 < L2.

[0011] Optionally, the width of the limiting cutting edge along its extension direction is ≥1mm;

[0012] And / or, along the radial direction away from its own central axis, the width of multiple limiting sub-cutting edges of the same limiting cutting edge increases sequentially.

[0013] Optionally, along the axial direction of the cutting section, the cutting edge height of the limiting sub-cutting edge is 0.5mm-1.0mm.

[0014] Optionally, the end corner of the limiting sub-cutting edge is provided with a first chamfer, the first chamfer near the first end is a circular arc structure, the groove width of the first cutting groove is d1, the width of the limiting sub-cutting edge corresponding to the first cutting groove along the radial direction of the cutting segment is d2, D1-L1=L2-D1-d1=(d2-d1) / 2; the radius of the circular arc structure is less than (d2-d1) / 2.

[0015] Optionally, the forming cutting edge includes a first cutting edge, a second cutting edge, and a third cutting edge that are sequentially connected along the direction from the first end to the second end;

[0016] Along the direction from the first end to the second end, the distance between the first cutting edge and the central axis of the cutting segment increases non-linearly, the extension direction of the second cutting edge is parallel to the central axis of the cutting segment, and along the direction from the first end to the second end, the distance between the third cutting edge and the central axis of the cutting segment increases linearly.

[0017] Optionally, the cutting tool further includes a clamping section connected to the second end of the cutting section to form the main structure of the cutting tool. The cutting section and the clamping section are both made of tungsten carbide-based cemented carbide, and the forming cutting edge and the limiting cutting edge are both made of polycrystalline diamond.

[0018] Optionally, the third cutting edge includes a plurality of contoured sub-cutting edges spaced apart along its own extension direction. A second cutting groove is formed between two adjacent contoured sub-cutting edges of the same third cutting edge. Among two adjacent third cutting edges spaced apart circumferentially along the cutting segment, the second cutting groove on one third cutting edge is complementary to the contoured sub-cutting edge of the other third cutting edge. Along the generatrix direction of the third cutting edge, the distance between the intersection of the inner wall of the second cutting groove and the generatrix and the intersection of the second cutting edge and the third cutting edge is D2. The distance between two points on the generatrix of the contoured sub-cutting edge corresponding to the second cutting groove and another intersection of the corresponding second cutting edge and the third cutting edge is a minimum distance L3 and a maximum distance L4, respectively, where L3 < D2 < L4.

[0019] Optionally, the width of the contour-following cutting edge along its own extension direction is ≥1mm;

[0020] And / or, in a direction away from the axis of the cutting segment itself, the width of all the contouring sub-cutting edges of the same forming cutting edge increases sequentially.

[0021] Optionally, the extension direction of the contour cutting edge is set at an angle to the axial direction of the cutting section, and the cutting edge height of the contour cutting edge is 0.5mm-1.0mm along the groove depth direction of the second cutting groove.

[0022] Optionally, the spacing between the second cutting grooves on the generatrix of the third cutting edge is d3, and the width of the contour cutting edge corresponding to the second cutting groove on its own generatrix is ​​d4, D2-L3=L4-D2-d3=(d4-d3) / 2;

[0023] The end corner of the contour cutting edge is provided with a second rounded corner; the radius of the second rounded corner is less than (d4-d3) / 2.

[0024] The beneficial effects of this invention are:

[0025] This invention provides a cutting tool comprising a cutting section having a first end and a second end disposed opposite to each other. At least two shaped cutting edges, evenly spaced along the circumference of the first end, are used to cut the inner surface of a multi-step blind hole. This allows the tool to adapt to the machining requirements of various hole types in multi-step blind holes, eliminating the need for multiple tools of different shapes for step-by-step machining or frequent tool changes on a single machine tool. This improves machining efficiency and avoids inconsistencies in the machining depth accuracy of multi-step blind holes caused by frequent tool changes or reference offsets. Furthermore, by setting limiting cutting edges that are one-to-one connected to the shaped cutting edges to cut the blank, the influence of blank dimensional deviations on the blind hole machining depth can be avoided, further ensuring the consistency of blind hole machining depth accuracy. The limiting cutting edges extending radially along the cutting section enable rapid machining of the blank, improving machining efficiency. Through the above-described configuration, the cutting tool of this application can adapt to the machining requirements of multi-step blind holes, improving machining accuracy and operational efficiency. Attached Figure Description

[0026] Figure 1 This is a first front view of the cutting tool provided in an embodiment of the present invention;

[0027] Figure 2 This is a first isometric view of the cutting tool provided in an embodiment of the present invention;

[0028] Figure 3 yes Figure 2 A magnified view of a section at point A in the middle;

[0029] Figure 4 This is a second isometric view of the cutting tool provided in an embodiment of the present invention;

[0030] Figure 5 This is a second front view of the cutting tool provided in an embodiment of the present invention;

[0031] Figure 6 yes Figure 5 A magnified view of a section at point B in the middle;

[0032] Figure 7 yes Figure 5 A magnified view of a section at point C;

[0033] Figure 8 This is a partial enlarged view of the cutting tool provided in an embodiment of the present invention;

[0034] Figure 9 This is a cross-sectional view of a multi-step blind hole provided in an embodiment of the present invention.

[0035] In the picture:

[0036] 100. Multi-step blind hole; 1. Cutting section; 11. First end; 12. Second end; 2. Forming cutting edge; 21. First cutting edge; 22. Second cutting edge; 23. Third cutting edge; 231. Contouring cutting edge; 2311. Second rounded corner; 232. Second cutting groove; 3. Limiting cutting edge; 31. Limiting cutting edge; 311. First chamfer; 32. First cutting groove; 4. Clamping section. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0041] In the powder metallurgy industry, products with multiple stepped blind holes (such as cylindrical holes, conical holes, and spherical holes) are widely used, and the processing of these blind holes is a key production step. Because the dense sintered body after high-temperature sintering has high hardness, blind holes cannot be obtained through machining methods such as drilling with cutting tools or grinding with abrasive wheels. Electrical discharge machining (EDM) is not only inefficient and costly, but also requires materials with good electrical conductivity, making it difficult to guarantee the machining accuracy of the blind holes. Therefore, the industry generally first forms a blank without blind holes, or pre-sintersects the blank at low temperature to obtain a pre-sintered blank with a certain strength. Since the internal particles of the blank and the pre-sintered blank are only mechanically interlocked or have a small amount of weak metallurgical bonding, it is relatively easy to drill to obtain multi-step blind holes with the required dimensions. Finally, the processed blank is sintered at high temperature to obtain a dense product with stepped blind holes.

[0042] However, existing multi-step blind hole machining still has the following problems: First, because multi-step blind holes include various hole types (such as cylindrical holes, conical holes, and spherical holes), multiple tools of different shapes are required for step-by-step machining, or frequent tool changes are required on a single machine tool. This not only leads to frequent adjustments of the machining datum (tool setting), significantly reducing machining efficiency, but also makes it difficult to ensure the consistency of the machining depth accuracy of each step of the blind hole. Especially when the dimensional accuracy of the pre-sintered blank itself is poor, the difference in blank size will directly cause the machining datum to shift, further aggravating the fluctuation of the blind hole depth. Second, in order to improve the datum shift problem, operators generally first perform "regularization" machining on the surface to be machined on the pre-sintered blank to unify the total height of the blank, or use a probe to test the position coordinates of the surface to be machined online to adjust the starting position of the tool. However, "regularization" machining requires additional tools or secondary clamping, which increases the risk of machining defects, increases costs, and reduces machining efficiency. Moreover, due to the softness of the pre-sintered blank and the unevenness of the end face, the probe has insufficient testing accuracy, thus failing to effectively guarantee the consistency of the blind hole machining depth.

[0043] Therefore, there is an urgent need for a cutting tool to solve the above-mentioned technical problems.

[0044] like Figures 1-9 As shown, this embodiment provides a cutting tool, which includes a cutting section 1. The cutting section 1 has a first end 11 and a second end 12 arranged opposite to each other. The first end 11 is provided with at least two forming cutting edges 2 arranged at equal intervals along its circumference, and a limiting cutting edge 3 corresponding to each forming cutting edge 2. The limiting cutting edge 3 is connected to the end of the corresponding forming cutting edge 2 near the second end 12, and the limiting cutting edge 3 extends radially along the cutting section 1.

[0045] In this embodiment, the cutting section 1 has a first end 11 and a second end 12 arranged opposite to each other. At least two forming cutting edges 2, evenly spaced along the circumference of the first end 11, are used to cut the inner surface of the multi-step blind hole 100. This adapts to the machining requirements of various hole types in the multi-step blind hole 100, eliminating the need for multiple cutting tools of different shapes for step-by-step machining or frequent tool changes on a single machine tool. This improves machining efficiency and avoids inconsistencies in the machining depth accuracy of the multi-step blind hole 100 caused by frequent tool changes or reference offsets. Furthermore, by setting limiting cutting edges 3 that are one-to-one connected to the forming cutting edges 2 to cut the blank, the influence of blank size deviations on the blind hole machining depth can be avoided, further ensuring the consistency of the blind hole machining depth accuracy. By extending the limiting cutting edges 3 radially along the cutting section 1, rapid machining of the blank can be achieved, improving machining efficiency. With the above settings, the cutting tool of this embodiment can adapt to the processing requirements of multi-step blind holes 100, improve processing accuracy and work efficiency, thereby solving the problems of poor processing accuracy consistency of complex-shaped step blind holes in pre-sintered blanks, and easy chipping or cracking of pre-sintered blanks and easy chipping of cutting tools caused by large cutting forces.

[0046] The specific structure of the cutting tool is described below:

[0047] Specifically, such as Figure 1 and Figure 2 As shown, the cutting tool also includes a clamping section 4, which is connected to the second end 12 of the cutting section 1 to form the main structure of the cutting tool. This ensures the stability of the connection between the clamping section 4 and the cutting section 1, which helps improve machining accuracy and avoids tool wobble caused by loosening of the connection between the clamping section 4 and the cutting section 1 during machining. Both the clamping section 4 and the cutting section 1 are made of tungsten carbide-based cemented carbide, providing sufficient matrix strength and rigidity to support the cutting force during the cutting process. Furthermore, the clamping section 4 and the cutting section 1 can be integrally formed to improve the strength of the cutting tool itself. The forming cutting edge 2 and the limiting cutting edge 3 are both made of polycrystalline diamond (PCD), which has significantly better wear resistance than traditional cemented carbide, extending the service life of the cutting tool. The forming cutting edge 2, the limiting cutting edge 3, and the cutting section 1 are connected by sintering or welding, thereby improving the connection strength between these components.

[0048] Specifically, in this embodiment, there are two forming cutting edges 2 and two limiting cutting edges 3 respectively. The two forming cutting edges 2 are symmetrically arranged, and the two limiting cutting edges 3 are symmetrically arranged, which enables the cutting force to be evenly distributed on both sides of the cutting section 1 when the cutting tool rotates for machining, thereby improving machining stability and the dimensional accuracy of the blind hole. Moreover, the two limiting cutting edges 3 are connected to the two forming cutting edges 2 in a one-to-one correspondence, which can ensure that the forming cutting edges 2 and the limiting cutting edges 3 participate in the machining operation synchronously, and at the same time improve the connection strength of the above components.

[0049] More specifically, on one side of the forming cutting edge 2 and the limiting cutting edge 3, the cutting section 1 is provided with a chip removal groove. The chip removal groove can be set as a spiral or a straight groove, so as to promptly remove the pre-sintered blank chips generated during the processing from the processing area and avoid chip accumulation.

[0050] To precisely control the consistency of blind hole machining dimensions, the limiting cutting edge 3 can precisely control the total depth of the machined blind holes, thereby ensuring the consistency of the depth of each blind hole during batch machining. This avoids depth deviations caused by manual tool setting errors or blank positioning deviations, reducing the defect rate. The limiting cutting edge 3 can be a continuous cutting edge (such as...) Figure 1 ( ), or it can be a discontinuous cutting edge. Preferably, the limiting cutting edge 3 is a discontinuous cutting edge.

[0051] Specifically, such as Figures 2-8 As shown, the limiting cutting edge 3 includes multiple limiting sub-cutting edges 31 spaced apart along its own extension direction. This arrangement reduces the cutting resistance of the limiting cutting edge 3. A first cutting groove 32 is formed between two adjacent limiting sub-cutting edges 31 in the same limiting cutting edge 3. Among two adjacent limiting cutting edges 3 distributed circumferentially along the cutting segment 1, the first cutting groove 32 on one limiting cutting edge 3 is complementary to the limiting sub-cutting edge 31 of the other limiting cutting edge 3. Let the included angle between two adjacent limiting cutting edges be ω. The complementary arrangement means that when one limiting cutting edge 3 is rotated by an angle ω along the central axis of the cutting segment 1 to coincide with the other limiting cutting edge 3, the position of the first cutting groove 32 of one limiting cutting edge 3 corresponds to the position of the limiting sub-cutting edge 31 of the other limiting cutting edge 3, thereby realizing complementary cutting operations and avoiding blind spots in the machining process. Along the radial direction of the cutting section 1, the distance between the inner wall of the first cutting groove 32 and the central axis of the cutting section 1 is D1. The distance between the two side walls of the limiting cutting edge 31 corresponding to the first cutting groove 32 and the central axis of the cutting section 1 is the minimum distance L1 and the maximum distance L2, respectively, where L1 < D1 < L2. This ensures that the cutting area of ​​all limiting cutting edges 3 completely covers the end face of the blank, avoiding the presence of unprocessed parts on the end face of the blank due to the cutting blind zone.

[0052] Because many machined surfaces have a large width in a single pass, the cutting edge of the tool on the corresponding machined surface needs to be relatively long. Even with a small depth of cut, a large cutting resistance will be generated, which can easily lead to chipping, cracking, and tool breakage in the pre-sintered blank. However, reducing the depth of cut will reduce the machining efficiency. To address this, by using multiple spaced limiting cutting edges 31, the cutting resistance of the limiting cutting edges 3 can be reduced, making it less likely for the pre-sintered blank to chip or crack, and the tool to break, thereby improving machining efficiency.

[0053] Specifically, the width of the limiting cutting edge 31 along the extension direction of the limiting cutting edge 3 is ≥1mm, so that the limiting cutting edge 31 has sufficient edge strength to avoid chipping when the width of the limiting cutting edge 31 is less than 1mm.

[0054] And / or, along the radial direction of the cutting segment 1 away from its own central axis, the widths of multiple limiting sub-cutting edges 31 of the same limiting cutting edge 3 increase sequentially, so that the strength of the limiting sub-cutting edges 31 at each radial position matches the force, ensuring that the limiting sub-cutting edges 31 located on the radially outer side of the cutting segment 1 also have sufficient anti-chipping ability. It can be understood that, since the linear velocity of the cutting tool rotation is greater the further away from its own central axis along the radial direction of the cutting segment 1, and the corresponding force on the limiting sub-cutting edges 31 is greater, it is necessary to increase the width of the limiting sub-cutting edges 31 sequentially to prevent them from chipping.

[0055] Specifically, along the axial direction of the cutting section 1, the cutting edge height of the limiting cutting edge 31 is 0.5mm-1.0mm. The "cutting edge height" refers to the distance between the top and bottom ends of the limiting cutting edge 31 along the axial direction. By setting it as described above, the single cutting depth and cutting resistance are balanced, which can ensure both a certain processing efficiency and the safety of the processing operation. It avoids the cutting resistance from surging due to excessive cutting edge height, and prevents the blank from chipping or the cutting tool from chipping due to excessive cutting resistance.

[0056] Specifically, a first chamfer 311 is provided at the end corner of the limiting cutting edge 31 to improve the strength of the limiting cutting edge 31 and reduce stress concentration at the end corner of the limiting cutting edge 31. The first chamfer 311 near the first end 11 is an arc structure. The groove width of the first cutting groove 32 is d1, and the width of the limiting cutting edge 31 corresponding to the first cutting groove 32 along the radial direction of the cutting section 1 is d2. D1-L1=L2-D1-d1=(d2-d1) / 2; the radius of the arc structure is less than (d2-d1) / 2 to avoid the arc structure being too large and generating a cutting blind zone, resulting in unprocessed parts remaining on the end face of the blank.

[0057] Specifically, in order to process and obtain such Figure 9The stepped blind hole shown (a multi-step structure consisting of a spherical hole, a cylindrical hole, and a conical hole from bottom to top) is as follows: Figures 1-8 As shown, the forming cutting edge 2 includes a first cutting edge 21, a second cutting edge 22, and a third cutting edge 23 connected sequentially along the direction from the first end 11 to the second end 12. Along the direction from the first end 11 to the second end 12, the distance between the first cutting edge 21 and the central axis of the cutting segment 1 increases non-linearly. The extension direction of the second cutting edge 22 is parallel to the central axis of the cutting segment 1. Along the direction from the first end 11 to the second end 12, the distance between the third cutting edge 23 and the central axis of the cutting segment 1 increases linearly. This configuration improves machining efficiency and enables one-time forming of the multi-step blind hole 100 without the need to change cutting tools or adjust the machining position.

[0058] In this embodiment, the cutting profile of the first cutting edge 21 is a spherical arc segment that matches the inner spherical surface profile of the spherical hole in the multi-step blind hole 100 to be machined, and the radius of curvature of the spherical arc segment is consistent with the radius of curvature of the inner spherical surface of the spherical hole, so as to form the inner surface of the spherical hole that meets the dimensional requirements by rotating the cutting tool; the cutting profile of the second cutting edge 22 is a straight line segment or a cylindrical generatrix segment that matches the inner cylindrical surface profile of the cylindrical hole in the multi-step blind hole 100 to be machined, and the profile segment... The extension direction is parallel to the rotation axis of the cutting tool, so that a cylindrical inner surface of the hole with an axis coaxial with the rotation axis of the cutting tool can be formed by rotating the cutting tool; the cutting working profile of the third cutting edge 23 is an inclined generatrix segment that matches the inner conical surface profile of the conical hole in the multi-step blind hole 100 to be machined, and the angle between the inclined generatrix segment and the rotation axis of the cutting tool is equal to the angle between the generatrix of the inner conical surface of the conical hole and its own axis, so that a conical inner surface of the hole with the required taper can be formed by rotating the cutting tool. During drilling, the inner surface of the hole can be obtained by rotating the cutting tool one revolution along its own axis. Figure 9 The multi-step blind hole 100 shown improves machining accuracy and work efficiency.

[0059] More specifically, such as Figures 2-8As shown, due to the long generatrix of the conical structure in the stepped blind hole, the cutting resistance of the third cutting edge 23 is relatively large. Therefore, in order to reduce the cutting resistance, the third cutting edge 23 includes multiple contoured sub-cutting edges 231 spaced apart along its own extension direction. A second cutting groove 232 is formed between two adjacent contoured sub-cutting edges 231 of the same third cutting edge 23. Among two adjacent third cutting edges 23 spaced apart along the circumference of the cutting section 1, the second cutting groove 232 on one third cutting edge 23 is complementary to the contoured sub-cutting edge 231 of the other third cutting edge 23. Let the included angle between two adjacent third cutting edges 23 be ω'. The complementary arrangement means that when one third cutting edge 23 is rotated along the central axis of the cutting section 1 by an angle ω' to coincide with another third cutting edge 23, the position of the second cutting groove 232 of one third cutting edge 23 corresponds to the position of the contoured sub-cutting edge 231 of the other third cutting edge 23, thereby realizing complementary cutting operations and avoiding blind spots in the machining process. Along the generatrix direction of the third cutting edge 23, the intersection points of the second cutting edge 22 and the corresponding third cutting edge 23 are O and O'. The distance between the intersection point E of the inner wall of the second cutting groove 232 and the generatrix and the intersection point O of the second cutting edge 22 and the third cutting edge 23 is D2. The distances between the two points F and G of the contour cutting edge 231 corresponding to the second cutting groove 232 on the generatrix and the other intersection point O' of the corresponding second cutting edge 22 and the third cutting edge 23 are the minimum distance L3 and the maximum distance L4, respectively, where L3 < D2 < L4. This ensures that the cutting area of ​​all the third cutting edges 23 completely covers the end face of the blank, avoiding the presence of unprocessed parts on the end face of the blank due to the cutting blind zone.

[0060] Specifically, the width of the contour cutting edge 231 along its own extension direction is ≥1mm, so that the contour cutting edge 231 has sufficient edge strength to avoid chipping when the width of the contour cutting edge 231 is less than 1mm.

[0061] And / or, in a direction away from the axis of the cutting section 1, the width of all the contouring sub-cutting edges 231 of the same forming cutting edge 2 increases sequentially, so that the strength of the contouring sub-cutting edges 231 at each radial position matches the force, ensuring that the contouring sub-cutting edges 231 located on the radially outer side of the cutting section 1 also have sufficient anti-chipping ability. It can be understood that, since the linear velocity of the cutting tool rotation is greater the further away from the axis of the cutting section 1, and the greater the force on the corresponding contouring sub-cutting edges 231, it is necessary to increase the width of the contouring sub-cutting edges 231 sequentially to prevent chipping.

[0062] Specifically, the extension direction of the contour cutting edge 231 is set at an angle to the axial direction of the cutting section 1 to adapt to the inclination angle of the generatrix of the tapered hole in the multi-step blind hole 100, thereby improving the accuracy of the cutting process. Along the groove depth direction of the second cutting groove 232, the cutting edge height of the contour cutting edge 231 is 0.5mm-1.0mm. The "cutting edge height" refers to the distance between the top and bottom of the contour cutting edge 231 along the groove depth direction of the second cutting groove 232. Through the above settings, the single cutting depth and cutting resistance are balanced, which can ensure a certain processing efficiency and the safety of the processing operation. It avoids the cutting resistance from surging due to excessive cutting edge height, thereby preventing the blank from chipping or the cutting tool from chipping due to excessive cutting resistance.

[0063] Specifically, the distance between the second cutting groove 232 and the generatrix of the third cutting edge 23 is d3, and the width of the contour cutting edge 231 corresponding to the second cutting groove 232 on its own generatrix is ​​d4, where D2-L3=L4-D2-d3=(d4-d3) / 2; a second rounded corner 2311 is provided at the end corner of the contour cutting edge 231 to improve the strength of the contour cutting edge 231, reduce stress concentration at the end corner of the contour cutting edge 231, and improve the impact resistance of the cutting edge. The radius of the second rounded corner 2311 is less than (d4-d3) / 2 to avoid the radius of the arc structure of the second rounded corner 2311 being too large, which would create a cutting blind zone and result in unprocessed parts remaining on the end face of the blank.

[0064] It should be noted that for two blanks of different heights, when the rear ends of the two blanks are positioned in the same way (the bottom of the blanks is fixed to the same reference surface by a tooling fixture), the positions of the machined end faces of the two blanks will be inconsistent. In this case, when the machining distance of the cutting tool is the same, the depth of the blind hole machined in the two blanks will inevitably be inconsistent. Moreover, since the opening diameter of the tapered hole in the multi-step blind hole 100 is related to the machining depth, the opening diameter of the tapered hole will also be different. Based on this, the cutting tool in this embodiment solves the above-mentioned technical problems by setting a limiting cutting edge 3. When the machining distance of the cutting tool is the same, the limiting cutting edge 3 removes a portion of the ends of the two blanks, thereby ensuring the consistency of the blind hole machining depth. Moreover, after machining, the height of the two blanks can also be kept consistent, avoiding the inconsistency between the blind hole depth and the finished blank height due to the deviation of the original height of the blanks. No additional adjustment of machining parameters or replacement of tooling is required, thus solving the problem of poor machining accuracy consistency of complex-shaped step blind holes in (pre-sintered) blanks.

[0065] It should be further explained that the end face obtained by rotating the limiting cutting edge 3 along the central axis of the cutting section 1 is not limited to the planar structure of this embodiment. The shape of the limiting cutting edge 3 can be changed accordingly according to the requirements of the rotation axis symmetry shape of the end face of the pre-burned workpiece.

[0066] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A cutting tool, characterized in that, It includes a cutting section (1), which has a first end (11) and a second end (12) disposed opposite to each other. The first end (11) is provided with at least two forming cutting edges (2) arranged at equal intervals along its circumference, and a limiting cutting edge (3) corresponding to each of the forming cutting edges (2). The limiting cutting edge (3) is connected to the end of the corresponding forming cutting edge (2) near the second end (12), and the limiting cutting edge (3) extends radially along the cutting section (1); The limiting cutting edge (3) includes a plurality of limiting sub-cutting edges (31) spaced apart along its own extension direction. A first cutting groove (32) is formed between two adjacent limiting sub-cutting edges (31) in the same limiting cutting edge (3). Among two adjacent limiting cutting edges (3) distributed circumferentially along the cutting segment (1), the first cutting groove (32) provided on one of the limiting cutting edges (3) is complementary to the limiting sub-cutting edge (31) of the other limiting cutting edge (3).

2. The cutting tool according to claim 1, characterized in that, Along the radial direction of the cutting segment (1), the distance between the inner wall of the first cutting groove (32) and the central axis of the cutting segment (1) is D1. The distance between the two side walls of the limiting sub-cutting edge (31) corresponding to the first cutting groove (32) and the central axis of the cutting segment (1) is the minimum distance L1 and the maximum distance L2, respectively, where L1 < D1 < L2.

3. The cutting tool according to claim 2, characterized in that, The width of the limiting cutting edge (31) along the extension direction of the limiting cutting edge (3) is ≥1mm; And / or, along the radial direction away from its own central axis, the width of the plurality of the limiting sub-cutting edges (31) of the same limiting cutting edge (3) increases sequentially.

4. The cutting tool according to claim 2, characterized in that, Along the axial direction of the cutting section (1), the cutting edge height of the limiting cutting edge (31) is 0.5mm-1.0mm.

5. The cutting tool according to claim 2, characterized in that, The end corner of the limiting sub-cutting edge (31) is provided with a first chamfer (311). The first chamfer (311) near the first end (11) is an arc structure. The groove width of the first cutting groove (32) is d1. The width of the limiting sub-cutting edge (31) corresponding to the first cutting groove (32) along the radial direction of the cutting segment (1) is d2. D1-L1=L2-D1-d1=(d2-d1) / 2; the radius of the arc structure is less than (d2-d1) / 2.

6. The cutting tool according to any one of claims 1-5, characterized in that, The forming cutting edge (2) includes a first cutting edge (21), a second cutting edge (22) and a third cutting edge (23) connected sequentially along the direction from the first end (11) to the second end (12). Along the direction from the first end (11) to the second end (12), the distance between the first cutting edge (21) and the central axis of the cutting segment (1) increases nonlinearly, the extension direction of the second cutting edge (22) is parallel to the central axis of the cutting segment (1), and along the direction from the first end (11) to the second end (12), the distance between the third cutting edge (23) and the central axis of the cutting segment (1) increases linearly. The cutting tool also includes a clamping section (4), which is connected to the second end (12) of the cutting section (1) to form the main structure of the cutting tool. The cutting section (1) and the clamping section (4) are both made of tungsten carbide-based cemented carbide, and the forming cutting edge (2) and the limiting cutting edge (3) are both made of polycrystalline diamond.

7. The cutting tool according to claim 6, characterized in that, The third cutting edge (23) includes a plurality of contoured sub-cutting edges (231) spaced apart along its own extension direction. A second cutting groove (232) is formed between two adjacent contoured sub-cutting edges (231) of the same third cutting edge (23). Among two adjacent third cutting edges (23) distributed circumferentially along the cutting segment (1), the second cutting groove (232) on one third cutting edge (23) is connected to the contoured sub-cutting edge (231) of the other third cutting edge (23). The complementary arrangement is such that, along the generatrix direction of the third cutting edge (23), the distance between the intersection of the inner wall of the second cutting groove (232) and the generatrix and the intersection of the second cutting edge (22) and the third cutting edge (23) is D2. The distance between the two points of the contoured sub-cutting edge (231) corresponding to the second cutting groove (232) on the generatrix and the other intersection of the corresponding second cutting edge (22) and the third cutting edge (23) is a minimum distance of L3 and a maximum distance of L4, respectively, where L3 < D2 < L4.

8. The cutting tool according to claim 7, characterized in that, The width of the contour cutting edge (231) along its own extension direction is ≥1mm; And / or, in a direction away from the axis of the cutting segment (1), the width of all the contouring sub-cutting edges (231) of the same forming cutting edge (2) increases sequentially.

9. The cutting tool according to claim 7, characterized in that, The extension direction of the contour cutting edge (231) is set at an angle to the axial direction of the cutting section (1), and the cutting edge height of the contour cutting edge (231) is 0.5mm-1.0mm along the groove depth direction of the second cutting groove (232).

10. The cutting tool according to claim 7, characterized in that, The distance between the second cutting groove (232) and the generatrix of the third cutting edge (23) is d3, and the width of the contour cutting edge (231) corresponding to the second cutting groove (232) on its own generatrix is ​​d4, D2-L3=L4-D2-d3=(d4-d3) / 2; The end corner of the contour cutting edge (231) is provided with a second rounded corner (2311); the radius of the second rounded corner (2311) is less than (d4-d3) / 2.

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