Self-sharpening drill bit and machining process thereof
By designing staggered cutting edge groups, main chip removal grooves, and gradient tungsten carbide particles in the self-sharpening drill bit, the problems of strength and rigidity contradiction and insufficient thermal management in existing drill bits during cutting are solved, achieving efficient and stable drilling results.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- QIANJIANG JIANGHAN DRILLING TOOLS CO LTD
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-01
AI Technical Summary
Existing self-sharpening drill bits suffer from a contradiction between strength and rigidity during cutting due to the chip flute design. They also lack stress dispersion and thermal management at the microscopic level, making them prone to unexpected failures such as chipping and thermal softening.
Three sets of cutting edges and the main chip removal groove are evenly distributed and staggered at 120° intervals along the length of the cutter body. Combined with the precise design of the spiral groove and chip removal groove, a continuous cutting and chip removal system is formed. High-hardness tungsten carbide particles are uniformly incorporated into the matrix through gradient material distribution technology to construct self-sharpening features.
It achieves balanced force distribution in all directions when the drill bit rotates at high speed, reduces radial runout and vibration, improves drilling accuracy and hole wall smoothness, extends the service life of the drill bit, and maintains high-efficiency cutting performance in composite material processing.
Smart Images
Figure CN121945845A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of drill bit manufacturing technology, and in particular to a self-sharpening drill bit and its processing technology. Background Technology
[0002] Self-sharpening drill bits, also known as self-tightening drill bits, are drill bits designed to automatically maintain or restore their sharpness after normal wear through specific material design or geometry. Their core principle is to actively guide the wear process, preferentially and controllably removing the relatively softer parts of the drill bit material, thereby continuously exposing new, high-hardness cutting elements or edges. This overcomes the drawback of traditional drill bits that quickly become dull and fail due to pure wear. These drill bits are mainly used in fields with stringent requirements for tool life, machining stability, and efficiency, especially in the machining of certain highly wear-resistant composite materials or homogeneous, difficult-to-machine materials in mechanical manufacturing. They can significantly reduce tool changes and improve overall work efficiency and economy.
[0003] In existing technologies, self-sharpening primarily relies on material composites and macroscopic groove design. One common structure is a matrix-type drill bit manufactured using powder metallurgy: its matrix is composed of metal alloy powders such as iron, copper, and cobalt, possessing a certain degree of toughness and wear resistance. Within the matrix, a large number of high-hardness tungsten carbide or synthetic diamond particles are dispersed as cutting abrasive grains through a sintering process. During operation, the softer metal matrix is preferentially worn, allowing the hard particles to continuously protrude and maintain cutting capability. Another structure focuses on the specific design of macroscopic chip flutes and cutting edges. For example, on the cutting edge of a solid carbide drill bit, a series of regularly distributed chip-breaking grooves, wavy edges, or asymmetrical chip-breaking grooves are created along the cutting edge. These grooves aim to separate chips, reduce cutting forces, and, by creating microscopic discontinuities at the cutting edge, attempt to make wear more uniform and delay the dulling trend. Some drill bits incorporate wear-resistant coatings, using the high hardness of the coating to extend the sharpness retention time.
[0004] Regarding the aforementioned technologies, the increased groove volume in existing technologies to improve chip removal often weakens the rigidity of the tool body, leading to a contradiction between strength and chip removal capacity. At the same time, the lack of effective stress dispersion and thermal management mechanisms at the microscopic level makes the drill bit prone to unexpected failures such as chipping and thermal softening under intermittent cutting or high temperature. Therefore, improvements are needed. Summary of the Invention
[0005] To address the aforementioned problems, this application provides a self-sharpening drill bit and its processing technology.
[0006] This application provides a self-sharpening drill bit and its processing technology, which adopts the following technical solution: A self-sharpening drill bit includes a drill body, which includes a handle, a blade, and a head. The handle is integrally disposed at one end of the blade, and the head is integrally disposed at the end of the blade away from the handle. The drill body is provided with a cutting edge group and a main chip removal groove. There are three sets of each cutting edge group and main chip removal groove, and the cutting edge group and main chip removal groove are staggered along the length of the drill body. The tangential angle of adjacent cutting edge groups and main chip removal grooves is 120°. The cutting edge assembly includes a first cutting edge, a second cutting edge, and a secondary chip removal groove. The secondary chip removal groove is formed between the first cutting edge and the second cutting edge. The first cutting edge has a first spiral groove and a second spiral groove, and multiple sets of the first spiral groove and the second spiral groove are formed at intervals. The second cutting edge has a third spiral groove and a fourth spiral groove, and multiple sets of the third spiral groove and the fourth spiral groove are formed at intervals.
[0007] By adopting the above technical solution, three sets of cutting edges, evenly distributed at 120° intervals along the length of the cutter body and arranged in an alternating pattern, together with the main chip removal groove, form a completely symmetrical cutting and chip removal system. This ensures that the drill bit is subjected to absolutely balanced forces in all directions during high-speed rotation, thereby fundamentally eliminating radial runout and vibration, and significantly improving the positioning accuracy and hole wall smoothness of the drilling. This alternating layout forms a continuous and unobstructed three-dimensional chip removal channel network around the cutter body, enabling the chips generated during cutting to be divided, guided, and discharged from the hole in a multi-stage and rapid manner. This greatly reduces the risk of frictional heating, sudden torque increase, and drill bit jamming caused by chip blockage. At the same time, it provides a stable and reliable macroscopic carrier for the subsequent setting of microscopic self-sharpening features on the cutting edge. Through the synergistic effect of macroscopic flow channels and microscopic features, it ensures that the drill bit can continuously maintain high-efficiency cutting performance and extend its service life during wear.
[0008] Optionally, multiple sets of first spiral grooves and second spiral grooves on the first cutting edge are formed along the same spiral line on the first cutting edge, and multiple sets of third spiral grooves and fourth spiral grooves on the second cutting edge are formed along the same spiral line on the second cutting edge. The spiral angles of the first spiral grooves and second spiral grooves are the same as those of the third spiral grooves and fourth spiral grooves, and the spiral directions of the first spiral grooves and second spiral grooves are opposite to those of the third spiral grooves and fourth spiral grooves.
[0009] By adopting the above technical solution, the first and second helical grooves on the first cutting edge, and the third and fourth helical grooves on the second cutting edge are precisely opened along two helical lines with the same helical angle but opposite directions. This allows multiple sets of micro-grooves to form two continuous and precise macroscopic guiding trajectories. These trajectories work in conjunction with the direction of the main cutting force, which not only smoothly disperses the cutting resistance but also guides the chips to curl and break in an orderly manner along a predetermined path, effectively reducing the local load and heat accumulation on the cutting edge. Furthermore, since the helical directions of the first and second helical grooves on the first cutting edge and the third and fourth helical grooves on the second cutting edge are opposite, a pair of micro-mechanical vortices with opposite directions and mutual constraints will be generated in the cutting area during drilling. This vortex effect can, on the one hand, perform secondary fine crushing of the formed chips to prevent long chips from entangled, and on the other hand, it is like applying a dynamic "mechanical stabilizing ring" in the tool tip area, which significantly enhances the drill bit's anti-yawing ability and dynamic rigidity at the moment of entry and penetration. Thus, when processing composite materials, laminated materials, and other conditions that are prone to delamination or burrs at the hole opening, cleaner and more precise drilling quality can be obtained.
[0010] Optionally, the spacing between adjacent first and second spiral grooves increases sequentially along the direction of the blade body towards the handle, and the third and fourth spiral grooves are configured with the same as the first and fourth spiral grooves.
[0011] By adopting the above technical solution, the spacing between adjacent first and second, third and fourth spiral grooves increases sequentially along the tool holder direction. This gradual design conforms to the natural distribution law of stress on the drill bit gradually decreasing from the tip to the tool holder during drilling. In the high-stress, high-wear area near the tip, the smaller groove spacing provides a higher micro-edge density and a more active chip-splitting ability, thereby enhancing the initial sharpness and penetration performance of the cutting edge. Towards the tool holder, as the groove spacing gradually increases, the material continuity of the cutting edge body is enhanced, and the structural stiffness is significantly improved. This effectively avoids the risk of microcrack initiation and propagation caused by stress concentration. This gradient layout from dense to sparse achieves a unity of sharp cutting edge tip and strong root, thereby improving the overall reliability and fatigue life of the drill bit under harsh working conditions such as intermittent cutting or lateral force.
[0012] Optionally, the width of the second spiral groove is greater than that of the first spiral groove, and the third and fourth spiral grooves are configured the same as the first and second spiral grooves.
[0013] By adopting the above technical solution, the width of the second spiral groove is designed to be greater than that of the first spiral groove. This stepped microstructure with alternating widths creates a collaborative division of labor mechanism between "pilot cutting" and "main chip containment" on a single cutting edge. The narrower first spiral groove acts as the "pilot cutting edge," responsible for the initial fine cutting of the workpiece material and forming an initial fine chip flow. The subsequent wider second spiral groove acts as the "main chip containment groove," providing ample space for further expansion, curling, and detachment of the chips, ensuring that the chips can be smoothly discharged without being squeezed and stuck in the groove. This application not only optimizes the chip removal smoothness within a single cutting edge unit, but the periodic cutting force changes it generates also help the workpiece material to produce beneficial micro-vibrations, thereby reducing the average cutting force and cutting heat. When machining tough materials such as stainless steel and titanium alloys, it can effectively promote chip breaking and avoid the formation of difficult-to-handle continuous ribbon-like chips that wrap around the drill bit.
[0014] Optionally, the width of the main chip removal groove gradually increases on the side near the cutter head, and the width of the main chip removal groove gradually increases on the side near the cutter shank. The width of the secondary chip removal groove gradually decreases on the side near the cutter head, and the width of the secondary chip removal groove gradually decreases on the side near the cutter shank. The narrowest point of the main chip removal groove and the widest point of the secondary chip removal groove are located on the same cross section.
[0015] By adopting the above technical solution, the width of the main chip removal groove gradually increases from its narrowest point in the middle towards both ends of the cutter head and the tool holder, while the width of the secondary chip removal groove gradually decreases from its widest point in the middle towards both ends. Furthermore, the narrowest and widest points of both are located on the same radial cross-section, constructing a highly optimized cross-sectional flow channel coupling system. On any cross-section of the drill bit, the sum of the cross-sectional areas of the main and secondary chip removal grooves remains relatively stable, providing a bottleneck-free and abrupt three-dimensional flow channel for chips and coolant. More importantly, this alternating and complementary spatial layout of "main wide, secondary narrow" and "main narrow, secondary wide" allows the overall chip removal channel to exhibit a natural contraction and expansion wave shape. This shape generates fluid dynamic characteristics similar to the "Venturi effect," not only accelerating the delivery and penetration of coolant to the high-temperature cutting tip region but also using pressure changes to efficiently push chips out of the hole. This achieves synergy between cooling, lubrication, and chip removal, making it suitable for drilling deep holes and high-profile materials with difficult chip removal.
[0016] Optionally, the cutting head includes a main cutting edge and a secondary cutting edge. The main cutting edge is pointed and includes three cutting surfaces. The tangential angle between adjacent cutting surfaces is 120°. Multiple sets of connecting grooves are formed on multiple sets of main cutting edges corresponding to multiple sets of cutting edge groups. Multiple sets of secondary cutting edges are provided. The multiple sets of secondary cutting edges are respectively located on the side of the multiple sets of connecting grooves away from the main cutting edge. The side of the secondary cutting edge close to the main cutting edge is inclined. The two ends of the connecting groove are respectively connected to two adjacent sets of main chip removal grooves. The side wall of the connecting groove away from the main cutting edge is connected to the secondary chip removal groove.
[0017] By adopting the above technical solution, the triangular pyramid-shaped main cutting edge, evenly distributed at 120°, can achieve rapid centering with minimal cutting resistance and maximum geometric stability, effectively preventing slippage during the initial drilling stage. The connecting groove on the main cutting edge directly connects the adjacent main chip removal grooves behind the drill tip, allowing the chips to be diverted and guided into the two main chip removal channels the instant they are generated, greatly alleviating the chip removal pressure and heat concentration in the core area of the drill tip. The inclined secondary cutting edge set behind the connecting groove has a dual function: on the one hand, it performs secondary finishing on the hole wall formed by the main cutting edge, significantly improving the surface quality and dimensional accuracy of the hole wall; on the other hand, it shares the load of the main cutting edge during normal operation and can immediately take over to participate in the main cutting after the main cutting edge wears out, thus ensuring the consistency of the hole diameter and the processing stability throughout the entire life cycle of the drill bit. This drill tip structure integrates rapid centering, efficient chip separation, smooth chip guidance, and continuous finishing, comprehensively improving the drill bit's penetration efficiency and hole quality.
[0018] Optionally, the tool body uses a matrix formed from Fe-based pre-alloyed powder as the main substrate, with a relatively low hardness of HRC45, which serves as a controllable wear phase. In the main substrate, the main cutting edge, secondary chip cutting edge, and cutting edge assembly are uniformly doped with submicron-sized tungsten carbide particles with a mass fraction of 15%-25% and a particle size of 0.8-2μm as a hard phase through gradient material distribution technology. The hard phase has a hardness of up to HRC80 or higher.
[0019] By adopting the above technical solution, during the cutting process, the softer Fe-based matrix preferentially undergoes uniform and controllable micro-wear, thereby ensuring that the high-hardness tungsten carbide particles can continuously and stably protrude from the cutting surface, like countless tiny "permanent cutting edges," allowing the drill bit to maintain its sharpness for a long time without resharpening throughout its entire lifespan. At the same time, the Fe-based matrix with good toughness effectively absorbs the impact and vibration during cutting, preventing the hard phase particles from collapsing over a large area due to brittleness. This gradient composite material design of "soft matrix wrapping hard points" perfectly reconciles the contradiction between high wear resistance and high toughness in tool materials, enabling the drill bit to simultaneously handle high-impact conditions and the machining of highly abrasive materials. It exhibits excellent durability and stability, especially in difficult-to-machine fields such as heterogeneous materials and composite materials. In addition, the gradient distribution of tungsten carbide particles ensures a smooth transition of wear resistance from the tip to the body, avoiding the scrapping of the entire drill bit due to premature local wear failure, making the service life of the drill bit predictable and long-lasting.
[0020] This application also includes a self-sharpening drill bit manufacturing process, comprising the following steps: S1: Fe-based alloy powder and submicron tungsten carbide particles with a mass fraction of 15-25% are layered and distributed in layers according to the areas of the cutting head, cutting body, and cutting handle; then, the material is sintered and densified in one go at a temperature and pressure exceeding 1000°C. The resulting blank has a hardness gradient that decreases from the cutting head to the cutting handle, and the macroscopic outline of three sets of 120° evenly distributed cutting edge groups and the main chip removal groove is initially pressed out on the outside. S2: Grind three sets of high-precision main chip removal grooves that extend along the tool body and whose cross-sectional width gradually increases from the narrowest point in the middle to both ends of the tool head and the tool holder. Between each set of main chip removal grooves, grind a complete tool edge group macro-edge surface including the first cutting edge, the second cutting edge, and the secondary chip removal groove. S3: A high-precision secondary chip removal groove is machined between the already formed first and second cutting edges, with the cross-sectional width gradually narrowing towards both ends of the tool head and tool holder. Then, a connecting groove is machined on the main cutting edge to form the required three-dimensional chip removal channel network. S4: Using a femtosecond ultrafast laser processing system, etching is performed by a high-precision scanning galvanometer to etch multiple sets of first and second spiral grooves on the first cutting edge; and multiple sets of third and fourth spiral grooves are etched on the second cutting edge. S5: Micro-blasting technology is used to passivate the main cutting edge and the secondary cutting edge in a consistent manner to eliminate micro-defects; then, selective electrolytic polishing is performed on the edge of the laser-etched spiral groove to further enhance its resistance to micro-chipping; finally, an AlTiN nanocomposite coating with a thickness of about 3 micrometers is deposited on the overall surface of the tool head through pulsed arc ion plating technology.
[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. Three sets of cutting edges, evenly distributed at 120° intervals along the length of the cutter body and arranged in an alternating pattern, together with the main chip removal groove, form a completely symmetrical cutting and chip removal system. This ensures that the drill bit is subjected to absolutely balanced forces in all directions when rotating at high speed, thereby fundamentally eliminating radial runout and vibration, and significantly improving the positioning accuracy and hole wall smoothness of the drilling. This staggered layout forms a continuous and unobstructed three-dimensional chip removal channel network around the cutter body, which allows the chips generated by cutting to be divided, guided and discharged from the hole in multiple stages and quickly, greatly reducing the risk of frictional heating, sudden torque increase and drill bit jamming caused by chip blockage.
[0022] 2. The first and second helical grooves on the first cutting edge, and the third and fourth helical grooves on the second cutting edge, are precisely opened along two helical lines with the same helical angle but opposite directions. This allows multiple sets of micro-grooves to form two continuous and precise macroscopic guiding trajectories. These trajectories work in conjunction with the direction of the main cutting force, which not only smoothly disperses the cutting resistance but also guides the chips to curl and break in an orderly manner along a predetermined path, effectively reducing the local load and heat accumulation on the cutting edge. Furthermore, the helical directions of the first and second helical grooves on the first cutting edge, and the third and fourth helical grooves on the second cutting edge, are opposite. During drilling, a pair of micro-mechanical vortices with opposite directions and mutual constraints are generated in the cutting area. This vortex effect can, on the one hand, perform secondary fine crushing of the formed chips to prevent long chips from entangled, and on the other hand, it is like applying a dynamic "mechanical stabilization ring" to the tip area, which significantly enhances the drill bit's anti-yawing ability and dynamic rigidity at the moment of entry and penetration. Thus, when processing composite materials, laminated materials, and other conditions that are prone to delamination or burrs at the hole opening, cleaner and more precise drilling quality can be obtained. 3. The spacing between adjacent first, second, third, and fourth spiral grooves increases sequentially along the tool holder direction. This gradual design conforms to the natural distribution law of stress on the drill bit gradually decreasing from the tip to the tool holder during drilling. In the high-stress, high-wear area near the tip, the smaller groove spacing provides a higher micro-edge density and a more aggressive chip-splitting capability, thereby enhancing the initial sharpness and penetration performance of the cutting edge. Towards the tool holder, as the groove spacing gradually increases, the material continuity of the cutting edge body is enhanced, and the structural rigidity is significantly improved. 4. The width of the second spiral groove is designed to be greater than that of the first spiral groove. This stepped microstructure with alternating widths creates a collaborative division of labor mechanism between "pilot cutting" and "main chip containment" on a single cutting edge. The narrower first spiral groove acts as the "pilot cutting edge," responsible for the initial fine cutting of the workpiece material and forming the initial fine chip flow. The wider second spiral groove that follows acts as the "main chip containment groove," providing ample space for the further expansion, curling, and detachment of the chips, ensuring that the chips can be smoothly discharged without being squeezed and stuck in the groove. 5. The width of the main chip removal groove gradually increases from its narrowest point in the middle towards both ends of the cutter head and shank, while the width of the secondary chip removal groove gradually decreases from its widest point in the middle towards both ends. Furthermore, the narrowest and widest points of both are located on the same radial cross-section, creating a highly optimized cross-sectional flow channel coupling system. On any cross-section of the drill bit, the total cross-sectional area of the main and secondary chip removal grooves remains relatively stable, providing a bottleneck-free and abrupt three-dimensional flow channel for chips and coolant. More importantly, this alternating and complementary spatial layout of "main wide, secondary narrow" and "main narrow, secondary wide" creates a natural contraction and expansion wave pattern in the overall chip removal channel. This pattern generates fluid dynamics similar to the "Venturi effect," accelerating the delivery and penetration of coolant to the high-temperature cutting tip region while simultaneously using pressure changes to efficiently push chips out of the hole. This achieves synergy in cooling, lubrication, and chip removal, making it suitable for drilling deep holes and high-profile materials with difficult chip removal. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 yes Figure 1 The front view; Figure 3 yes Figure 1 Side view; Figure 4 yes Figure 1 Top view.
[0025] Reference numerals: 1. Tool body; 11. Tool holder; 12. Tool body; 13. Tool tip; 131. Main cutting edge; 132. Secondary cutting edge; 133. Connecting groove; 2. Tool edge group; 21. First cutting edge; 211. First helical groove; 212. Secondary helical groove; 22. Secondary cutting edge; 221. Third helical groove; 222. Fourth helical groove; 23. Secondary chip removal groove; 3. Main chip removal groove. Detailed Implementation
[0026] The following is in conjunction with the appendix Figure 1-4 This application will be described in further detail.
[0027] This application discloses a self-sharpening drill bit and its processing technology, referring to... Figures 1-4A self-sharpening drill bit includes a drill body 1, which is made of a φ10 metal rod. The drill body 1 includes a handle 11, a blade 12, and a head 13. The handle 11 is integrally disposed at one end of the blade 12, and the head 13 is integrally disposed at the end of the blade 12 away from the handle 11. The drill body 1 is provided with a cutting edge group 2 and a main chip removal groove 3. There are three sets of cutting edge group 2 and main chip removal groove 3. The cutting edge group 2 and the main chip removal groove 3 are staggered along the length of the drill body 1. The tangential angle of adjacent cutting edge group 2 and main chip removal groove 3 is 120°. The cutting edge assembly 2 includes a first cutting edge 21, a second cutting edge 22, and a secondary chip removal groove 23. The secondary chip removal groove 23 is formed between the first cutting edge 21 and the second cutting edge 22. The first cutting edge 21 has a first spiral groove 211 and a second spiral groove 212, and multiple sets of the first spiral groove 211 and the second spiral groove 212 are formed at intervals. The second cutting edge 22 has a third spiral groove 221 and a fourth spiral groove 222, and multiple sets of the third spiral groove 221 and the fourth spiral groove 222 are formed at intervals.
[0028] Three sets of cutting edge groups 2, evenly distributed and staggered at 120° intervals along the length of the cutter body 1, together with the main chip removal groove 3, constitute a completely symmetrical cutting and chip removal system. This ensures that the drill bit is subjected to absolutely balanced forces in all directions during high-speed rotation, thereby fundamentally eliminating radial runout and vibration, and significantly improving the positioning accuracy and hole wall smoothness of the drilling. This staggered layout forms a continuous and unobstructed three-dimensional chip removal channel network around the cutter body 1, enabling the chips generated during cutting to be segmented, guided, and discharged from the hole in a multi-stage and rapid manner. This greatly reduces the risk of frictional heating, sudden torque increase, and drill bit jamming caused by chip blockage. At the same time, it provides a stable and reliable macroscopic carrier for the subsequent setting of microscopic self-sharpening features on the cutting edge. Through the synergistic effect of macroscopic flow channels and microscopic features, it ensures that the drill bit can maintain high-efficiency cutting performance and extend its service life during wear.
[0029] Reference Figure 1 , Figure 2 and Figure 3 Multiple sets of first cutting edges 21 have first spiral grooves 211 and second spiral grooves 212 formed along the same spiral line on the first cutting edge 21. Multiple sets of second cutting edges 22 have third spiral grooves 221 and fourth spiral grooves 222 formed along the same spiral line on the second cutting edge 22. The spiral angles of the first spiral grooves 211 and second spiral grooves 212 are the same as those of the third spiral grooves 221 and fourth spiral grooves 222. The spiral directions of the first spiral grooves 211 and second spiral grooves 212 are opposite to those of the third spiral grooves 221 and fourth spiral grooves 222. In this embodiment, the spiral angle of the first spiral grooves 211 and second spiral grooves 212 is +5°, and the spiral angle of the third spiral grooves 221 and fourth spiral grooves 222 is -5°.
[0030] The first helical groove 211 and the second helical groove 212 on the first cutting edge 21, and the third helical groove 221 and the fourth helical groove 222 on the second cutting edge 22 are precisely opened along two helical lines with the same helical angle but opposite directions. This allows multiple sets of micro-grooves to form two continuous and precise macroscopic guiding trajectories. These trajectories work in conjunction with the direction of the main cutting force, which not only smoothly disperses the cutting resistance but also guides the chips to curl and break in an orderly manner along a predetermined path, effectively reducing the local load and heat accumulation on the cutting edge. Furthermore, the first helical groove 211 and the second helical groove 212 on the first cutting edge 21, along with the third helical groove 221 and the fourth helical groove 222 on the second cutting edge 22, are precisely opened along two helical lines with the same helical angle but opposite directions. The third spiral groove 221 and the fourth spiral groove 222 on the second cutting edge 22 have opposite spiral directions. During drilling, they generate a pair of micro-mechanical vortices in opposite directions that are mutually restrictive in the cutting area. This vortex effect can, on the one hand, perform secondary fine crushing of the formed chips to prevent long chips from entangled, and on the other hand, it is like applying a dynamic "mechanical stabilizing ring" in the tip area, which significantly enhances the drill bit's anti-yawing ability and dynamic rigidity at the moment of entry and penetration. Thus, when processing composite materials, laminated materials, and other conditions that are prone to delamination or burrs at the hole opening, cleaner and more accurate drilling quality can be obtained.
[0031] Reference Figure 1 , Figure 2 and Figure 3 The spacing between adjacent first spiral grooves 211 and second spiral grooves 212 increases sequentially along the direction of the cutter body 1 towards the handle 11. The third spiral groove 221 and the fourth spiral groove 222 are set with the same as the first spiral groove 211 and the second spiral groove 212. In this embodiment, the minimum spacing between the first spiral groove 211 and the second spiral groove 212, the third spiral groove 221 and the fourth spiral groove 222 is 1mm, and then gradually increases in a gradient of 0.5mm. The spacing between adjacent first spiral grooves 211 and second spiral grooves 212, third spiral grooves 221 and fourth spiral grooves 222 increases sequentially along the direction of the tool holder 11. This gradual design conforms to the natural distribution law of the stress on the drill bit during drilling, which gradually decreases from the tip to the tool holder 11. In the high-stress, high-wear area near the tip, the smaller groove spacing provides a higher micro-edge density and a more active chip-splitting ability, thereby enhancing the initial sharpness and penetration performance of the cutting edge. Towards the tool holder 11, as the groove spacing gradually increases, the material continuity of the cutting edge body is enhanced, and the structural stiffness is significantly improved. This effectively avoids the risk of microcrack initiation and propagation caused by stress concentration. This gradient layout from dense to sparse achieves a unity of sharp cutting edge tip and strong root, thereby improving the overall reliability and fatigue life of the drill bit under harsh working conditions such as intermittent cutting or lateral force.
[0032] Reference Figure 1 , Figure 2 and Figure 3The second spiral groove 212 is wider than the first spiral groove 211. The third spiral groove 221 and the fourth spiral groove 222 are the same as the first spiral groove 211 and the second spiral groove 212. In this embodiment, the width of the first spiral groove 211 and the third spiral groove 221 is 1±0.05mm, and the width of the second spiral groove 212 and the fourth spiral groove 222 is 1.5+0.05mm. The width of the second spiral groove 212 is designed to be greater than that of the first spiral groove 211. This stepped microstructure with alternating widths creates a collaborative division of labor mechanism between "pilot cutting" and "main chip containment" on a single cutting edge. The narrower first spiral groove 211 acts as the "pilot cutting edge," responsible for the initial fine cutting of the workpiece material and forming an initial fine chip flow. The subsequent wider second spiral groove 212 acts as the "main chip containment groove," providing ample space for further expansion, curling, and detachment of the chips, ensuring that the chips can be smoothly discharged without being squeezed and stuck in the groove. This embodiment not only optimizes the chip removal smoothness within a single cutting edge unit, but the periodic cutting force changes it generates also help the workpiece material to produce beneficial micro-vibrations, thereby reducing the average cutting force and cutting heat. When machining tough materials such as stainless steel and titanium alloys, it can effectively promote chip breaking and avoid the formation of continuous, difficult-to-handle ribbon-like chips that wrap around the drill bit.
[0033] Reference Figure 1 , Figure 2 and Figure 3 The width of the main chip removal groove 3 gradually increases on the side near the cutter head 13, and the width of the main chip removal groove 3 on the side near the cutter shank 11 also gradually increases. The width of the secondary chip removal groove 23 gradually decreases on the side near the cutter head 13, and the width of the secondary chip removal groove 23 on the side near the cutter shank 11 also gradually decreases. The narrowest point of the main chip removal groove 3 and the widest point of the secondary chip removal groove 23 are located on the same cross section. In this embodiment, the maximum width of the main chip removal groove 3 is 4mm and the minimum width is 2mm, and the maximum width of the secondary chip removal groove 23 is 3mm and the minimum width is 2mm. The width of the main chip removal groove 3 gradually increases from its narrowest point in the middle towards both ends of the cutter head 13 and the tool holder 11, while the width of the secondary chip removal groove 23 gradually decreases from its widest point in the middle towards both ends. Furthermore, the narrowest and widest points of both are located on the same radial cross-section, creating a highly optimized cross-sectional flow channel coupling system. On any cross-section of the drill bit, the sum of the cross-sectional areas of the main chip removal groove 3 and the secondary chip removal groove 23 remains relatively stable, providing a bottleneck-free and abrupt three-dimensional flow channel for chips and coolant. More importantly, this alternating and complementary spatial layout of "main wide, secondary narrow" and "main narrow, secondary wide" creates a natural contraction and expansion wave pattern in the overall chip removal channel. This pattern generates fluid dynamic characteristics similar to the "Venturi effect," accelerating the delivery and penetration of coolant to the high-temperature cutting tip region. Simultaneously, it utilizes pressure changes to efficiently push chips out of the hole, thus achieving synergy in cooling, lubrication, and chip removal. This is suitable for drilling deep holes and materials with difficult chip removal in length-to-diameter ratio operations.
[0034] Reference Figure 2 , Figure 3 and Figure 4 The cutting head 13 includes a main cutting edge 131 and a secondary cutting edge 132. The main cutting edge 131 is pointed and has three cutting surfaces. The tangential angle between adjacent cutting surfaces is 120°. Multiple sets of connecting grooves 133 are provided on multiple sets of cutting edge groups 2. Multiple sets of secondary cutting edges 132 are provided. The multiple sets of secondary cutting edges 132 are respectively located on the side of the multiple sets of connecting grooves 133 away from the main cutting edge 131. The side of the secondary cutting edge 132 close to the main cutting edge 131 is inclined. The two ends of the connecting groove 133 are respectively connected to two adjacent sets of main chip removal grooves 3. The side wall of the connecting groove 133 away from the main cutting edge 131 is connected to the secondary chip removal groove 23. In this embodiment, the length of the main cutting edge 131 is 5mm and the length of the secondary cutting edge 132 is 1.5mm.
[0035] The triangular pyramidal main cutting edge 131, evenly distributed at 120°, enables rapid centering with minimal cutting resistance and maximum geometric stability, effectively preventing slippage during the initial drilling stage. A connecting groove 133 on the main cutting edge 131 directly connects the adjacent main chip removal groove 3 behind the drill tip, allowing chips to be diverted and guided into two main chip removal channels instantly upon generation, greatly alleviating chip removal pressure and heat concentration in the core area of the drill tip. The inclined secondary cutting edge 132, located behind the connecting groove 133, performs a dual function: firstly, it performs secondary finishing on the hole wall formed by the main cutting edge 131, significantly improving the surface quality and dimensional accuracy of the hole wall; secondly, it shares the load of the main cutting edge 131 during normal operation and can immediately take over the main cutting after wear, thus ensuring the consistency of the hole diameter and processing stability throughout the entire lifespan of the drill bit 13. This drill tip structure integrates rapid centering, efficient chip separation, smooth chip guidance, and continuous finishing, comprehensively improving the drill bit's penetration efficiency and hole quality.
[0036] In this embodiment, the cutter body 1 uses a matrix formed from Fe-based pre-alloyed powder as the main substrate, with a relatively low hardness of HRC45, which serves as a controllable wear phase. In the main substrate, the main cutting edge 131, the secondary chip cutting edge, and the cutting edge group are uniformly doped with submicron-sized tungsten carbide particles with a mass fraction of 15%-25% and a particle size of 0.8-2μm as a hard phase through gradient material distribution technology. The hard phase has a hardness of up to HRC80 or higher.
[0037] During the cutting process, the softer Fe-based matrix preferentially undergoes uniform and controllable micro-wear, ensuring that the high-hardness tungsten carbide particles can continuously and stably protrude from the cutting surface, acting like countless tiny "permanent cutting edges." This allows the drill bit to maintain its sharpness for an extended period without needing resharpening throughout its lifespan. Simultaneously, the Fe-based matrix, with its excellent toughness, effectively absorbs the impact and vibration during cutting, preventing the hard phase particles from collapsing over a large area due to brittleness. This gradient composite material design, where a "soft matrix envelops hard points," perfectly reconciles the inherent contradiction between high wear resistance and high toughness in tool materials. This allows the drill bit to handle both high-impact conditions and the machining of highly abrasive materials, exhibiting exceptional durability and stability, particularly in challenging applications such as heterogeneous materials and composite materials. Furthermore, the gradient distribution of tungsten carbide particles ensures a smooth transition in wear resistance from the tip to the body, preventing premature wear failure and thus ensuring a predictable and long-lasting service life for the drill bit.
[0038] The implementation principle of a self-sharpening drill bit in this application embodiment is as follows: At the material level, this embodiment employs a gradient composite material with a soft matrix encapsulating hard points. During cutting, the soft matrix is preferentially and uniformly abraded, causing high-hardness tungsten carbide particles to continuously protrude from the surface, forming dynamically renewed microscopic cutting edges and achieving inherent self-sharpening. At the structural level, three sets of staggered main chip removal grooves 3 and secondary chip removal grooves 23, evenly distributed at 120°, constitute a macroscopic carrier with absolutely balanced force and unobstructed chip removal. Among them, the spatial complementary coupling of the cross-sectional widths of the main chip removal grooves 3 and secondary chip removal grooves 23 forms a flow channel with a Venturi effect, efficiently coordinating cooling and chip removal; on the cutting edge, the first spiral groove 211 and the second spiral groove 212, the third spiral groove 221 and the fourth spiral groove 222, precisely distributed along opposite spiral lines, not only guide the orderly curling and breaking of chips, but also, through their gradient-changing spacing, microscopically programmatically guide controllable wear, keeping the tip area sharp while the body area 12 remains strong and tough.
[0039] This application also includes a self-sharpening drill bit manufacturing process: S1: Fe-based alloy powder and submicron tungsten carbide particles with a mass fraction of 15-25% are layered and distributed in the areas of the cutting head 13, the cutting body 12, and the shank 11. Then, the material is sintered and densified in one go at a temperature of over 1000°C and under high pressure. The resulting blank has a hardness gradient that decreases from the cutting head 13 to the shank 11. The macroscopic outline of the three sets of 120° evenly distributed cutting edge groups 2 and the main chip removal groove 3 is initially pressed out on the outside. S2: Grind three sets of high-precision main chip removal grooves 3 that extend along the cutter body 1 and whose cross-sectional width gradually increases from the narrowest point in the middle to both ends of the cutter head 13 and the handle 11. Between each set of main chip removal grooves 3, grind a complete cutting edge group 2 macro-cutting surface containing the first cutting edge 21, the second cutting edge 22 and the secondary chip removal groove 23. S3: A high-precision secondary chip removal groove 23 is machined between the already formed first cutting edge 21 and second cutting edge 22. The cross-sectional width gradually narrows towards both ends of the tool head 13 and tool holder 11. Then, a connecting groove 133 is machined on the main cutting edge 131 to form the required three-dimensional chip removal channel network. S4: Using a femtosecond ultrafast laser processing system, etching is performed by a high-precision scanning galvanometer to etch multiple sets of first spiral grooves 211 and second spiral grooves 212 on the first cutting edge 21; and multiple sets of third spiral grooves 221 and fourth spiral grooves 222 are etched on the second cutting edge 22. S5: Micro-blasting technology is used to uniformly passivate the main cutting edge 131 and the secondary cutting edge 132 to eliminate micro-defects; then, selective electrolytic polishing is performed on the edge of the laser-etched spiral groove to further enhance its resistance to micro-chipping; finally, an AlTiN nanocomposite coating of about 3 micrometers thick is deposited on the overall surface of the tool head 13 by pulsed arc ion plating technology.
[0040] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar words used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "a" or "an," and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising," "including," and similar words mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, but do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0041] The above are all optional embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A self-sharpening drill bit, characterized in that: The blade includes a blade body (1), which includes a handle (11), a blade (12), and a blade head (13). The handle (11) is integrally disposed at one end of the blade (12), and the blade head (13) is integrally disposed at the end of the blade (12) away from the handle (11). The blade body (1) is provided with a blade assembly (2) and a main chip removal groove (3). The blade assembly (2) and the main chip removal groove (3) are each provided with three sets. The blade assembly (2) and the main chip removal groove (3) are staggered along the length direction of the blade body (1). The sectional angle of adjacent blade assemblies (2) and main chip removal grooves (3) is 120°. The cutting edge assembly (2) includes a first cutting edge (21), a second cutting edge (22), and a secondary chip removal groove (23). The secondary chip removal groove (23) is located between the first cutting edge (21) and the second cutting edge (22). The first cutting edge (21) has a first spiral groove (211) and a second spiral groove (212). The first spiral groove (211) and the second spiral groove (212) are provided in multiple sets at intervals. The second cutting edge (22) has a third spiral groove (221) and a fourth spiral groove (222). The third spiral groove (221) and the fourth spiral groove (222) are provided in multiple sets at intervals.
2. A self-sharpening drill bit according to claim 1, characterized in that: Multiple sets of first spiral grooves (211) and second spiral grooves (212) on the first cutting edge (21) are opened along the same spiral line on the first cutting edge (21), and multiple sets of third spiral grooves (221) and fourth spiral grooves (222) on the second cutting edge (22) are opened along the same spiral line on the second cutting edge (22). The spiral angle of the first spiral groove (211) and the second spiral groove (212) is set with the same spiral angle as the third spiral groove (221) and the fourth spiral groove (222). The spiral direction of the first spiral groove (211) and the second spiral groove (212) is opposite to the spiral direction of the third spiral groove (221) and the fourth spiral groove (222).
3. A self-sharpening drill bit according to claim 2, characterized in that: The spacing between adjacent first spiral grooves (211) and second spiral grooves (212) increases sequentially along the direction of the blade body (1) near the handle (11), and the third spiral groove (221) and the fourth spiral groove (222) are provided with the same as the first spiral groove (211) and the fourth spiral groove (222).
4. A self-sharpening drill bit according to claim 2, characterized in that: The width of the second spiral groove (212) is greater than that of the first spiral groove (211), and the third spiral groove (221) and the fourth spiral groove (222) are the same as the first spiral groove (211) and the second spiral groove (212).
5. A self-sharpening drill bit according to claim 1, characterized in that: The width of the main chip removal groove (3) gradually increases on the side near the cutter head (13), and the width of the main chip removal groove (3) also gradually increases on the side near the cutter handle (11). The width of the secondary chip removal groove (23) gradually decreases on the side near the cutter head (13), and the width of the secondary chip removal groove (23) also gradually decreases on the side near the cutter handle (11). The narrowest point of the main chip removal groove (3) and the widest point of the secondary chip removal groove (23) are located on the same cross section.
6. A self-sharpening drill bit according to claim 1, characterized in that: The cutting head (13) includes a main cutting edge (131) and a secondary cutting edge (132). The main cutting edge (131) is set in a pointed shape and includes three cutting surfaces. The sectional angle between adjacent cutting surfaces is 120°. Multiple sets of connecting grooves (133) are opened on multiple sets of cutting edge groups (2) corresponding to multiple sets of cutting edge groups. Multiple sets of secondary cutting edges (132) are provided. The multiple sets of secondary cutting edges (132) are respectively set on the side of the multiple sets of connecting grooves (133) away from the main cutting edge (131). The side of the secondary cutting edge (132) close to the main cutting edge (131) is inclined. The two ends of the connecting groove (133) are respectively connected to two adjacent sets of main chip removal grooves (3). The side wall of the connecting groove (133) away from the main cutting edge (131) is connected to the secondary chip removal groove (23).
7. A self-sharpening drill bit according to claim 2, characterized in that: The cutter body (1) uses a matrix formed by Fe-based pre-alloyed powder as the main substrate, with a relatively low hardness of HRC45, which is used as a controllable wear phase. In the main substrate, the main cutting edge (131), the secondary chip cutting edge and the cutting edge group are uniformly doped with submicron-sized tungsten carbide particles with a mass fraction of 15%-25% and a particle size of 0.8-2μm as a hard phase through gradient material distribution technology. The hard phase has a hardness of up to HRC80 or higher.
8. A self-sharpening drill bit manufacturing process, wherein the self-sharpening drill bit according to claim 7 is characterized in that: Includes the following steps: S1: Fe-based alloy powder and submicron tungsten carbide particles with a mass fraction of 15-25% are layered and distributed in the areas of the cutting head (13), the cutting body (12), and the shank (11); then, the material is sintered and densified in one go at a temperature of over 1000°C and under high pressure. The resulting blank has a hardness gradient that decreases from the cutting head (13) to the shank (11) inside, and the macroscopic outline of three sets of 120° evenly distributed cutting edge groups (2) and the main chip removal groove (3) is initially pressed out on the outside. S2: Grind three sets of high-precision main chip removal grooves (3) that extend along the cutter body (1) and whose cross-sectional width gradually increases from the narrowest point in the middle to both ends of the cutter head (13) and the shank (11). Between each set of main chip removal grooves (3), grind a complete cutting edge group (2) macro-cutting surface containing the first cutting edge (21), the second cutting edge (22) and the secondary chip removal groove (23). S3: A high-precision secondary chip removal groove (23) is machined between the already formed first cutting edge (21) and second cutting edge (22), with the cross-sectional width gradually narrowing towards both ends of the tool head (13) and tool holder (11). Then, a connecting groove (133) is machined on the main cutting edge (131) to form the required three-dimensional chip removal channel network. S4: Using a femtosecond ultrafast laser processing system, etching is performed by a high-precision scanning galvanometer to etch multiple sets of first spiral grooves (211) and second spiral grooves (212) on the first cutting edge (21); and multiple sets of third spiral grooves (221) and fourth spiral grooves (222) are etched on the second cutting edge (22). S5: Micro-blasting technology is used to passivate the main cutting edge (131) and the secondary cutting edge (132) in a consistent manner to eliminate micro-defects; then, selective electropolishing is performed on the edge of the laser-etched spiral groove to further enhance its resistance to micro-chipping; finally, an AlTiN nanocomposite coating of about 3 micrometers thick is deposited on the overall surface of the drill bit through pulsed arc ion plating technology.