A drill bit

Abstract

The application discloses a drill bit, and relates to the technical field of machinery, which comprises a drill body, a drill tip arranged on one side of the drill body along the length direction of the drill body, a main cutting edge and a secondary cutting edge arranged on the drill tip, a main spiral groove extended from the side of the main cutting edge away from the tip end of the drill tip, a secondary spiral groove extended from the side of the secondary cutting edge away from the tip end of the drill tip, a single groove formed by the intersection of the main spiral groove and the secondary spiral groove at a first position of the drill body in the direction away from the drill tip, and a second position of the drill body in the direction away from the drill tip, wherein the length between the tip end of the drill tip and the first position is L1, the straight line length between the first position and the second position is L2, and L1 is less than or equal to L2. The structural design effectively expands the chip removal space of the drill bit, prevents chip retention, improves the chip removal smoothness and efficiency, prolongs the service life of the drill bit, reduces the risk of tool breakage, and improves the production efficiency.

Description

Technical Field

[0001] This invention relates to the field of mechanical technology, and in particular to a drill bit. Background Technology

[0002] With the rapid development of the electronics and information industry, the demand for product delivery efficiency has increased dramatically across the industry's upstream and downstream sectors. Printed circuit boards (PCBs), as the carriers of the electronics and information industry, are crucial to ensuring product delivery efficiency. Automotive PCBs, in particular, are vital to vehicle operation and safety performance, and stringent driving standards place extremely high demands on the hole precision and dimensional tolerances of automotive PCBs. Drilling is a critical step in PCB manufacturing, directly determining the delivery efficiency and quality of the PCBs.

[0003] In terms of structural performance comparison, double-edged drill bits have relatively weak overall rigidity, and the hole position accuracy after machining is significantly weaker than that of single-edged drill bits; single-edged drill bits with a single flute structure have excellent rigidity, and the hole position accuracy is significantly better than that of double-edged drill bits, making them perfectly suited for the high-precision hole machining requirements of automotive boards.

[0004] However, in existing technologies, single-flute drills have the characteristic of low cutting temperature during cutting. Therefore, the resin softening in the chips is weak, the risk of chips adhering in the groove is lower, chip removal is smoother, and it is easier to obtain excellent hole wall quality. Therefore, single-flute drills have become one of the mainstream solutions in applications that improve processing efficiency through layering. However, single-flute drills also have their own shortcomings: chips are prone to accumulating in the secondary groove and are difficult to remove, which can easily lead to breakage of the single-flute drill, affecting its service life, and making it inconvenient for processing. Summary of the Invention

[0005] The present invention aims to at least solve one of the aforementioned technical problems existing in the prior art. Therefore, the object of the present invention is to provide a drill bit that effectively expands the chip removal space, prevents chip retention, improves chip removal smoothness and efficiency, extends the service life of the drill bit, reduces the risk of tool breakage, and improves production efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A drill bit includes: a drill body, a drill tip provided on one side along its length, the drill tip having a main cutting edge and a secondary cutting edge, the main cutting edge extending a main helical groove on the side away from the tip of the drill tip, the secondary cutting edge extending a secondary helical groove on the side away from the tip of the drill tip, the main helical groove and the secondary helical groove converging at a first position on the drill body in a direction away from the drill tip to form a single groove, the single groove extending to a second position on the drill body in a direction away from the drill tip; Wherein, the length between the tip of the drill bit and the first position is L1, and the straight line length between the first position and the second position is L2, then L1≤L2 is satisfied.

[0007] The beneficial effects of this invention are as follows: By precisely defining the value of L1, the main helical groove and the secondary helical groove can converge at the first position of the drill body to form a single groove, and the single groove extends to the second position of the drill body in a direction away from the drill tip, thereby effectively expanding the chip removal space of the drill bit, preventing chip retention, effectively improving chip removal smoothness and chip removal efficiency, extending the service life of the drill bit, and reducing the risk of tool breakage; at the same time, by pre-determining the value of L1, it is convenient to process according to a unified standard, improving the convenience and consistency of drill bit processing, thereby improving production efficiency.

[0008] In the drill bit described above, the drill diameter of the drill body is d, L1 is 1 to 5 times the drill diameter, and L2 is 15 to 80 times the drill diameter.

[0009] In the drill bit described above, the main helical groove has a groove width of GW1 in length L1, and the single groove has a groove width of GW2 in length L2. The value of GW1 ranges from 1.5 to 3.5 times the drill diameter, and the value of GW2 ranges from 1 to 2.5 times the drill diameter.

[0010] As described above, the core thickness of the main helical groove near the tip of the drill tip is K1, and the core thickness of the secondary helical groove near the tip of the drill tip is K2, wherein the value of K1 ranges from 15% to 60% of the drill diameter, and the value of K2 ranges from 10% to 70% of the drill diameter.

[0011] The drill bit described above has a drill diameter ranging from 0.01 mm to 0.8 mm.

[0012] In the drill bit described above, the helix angle between the main helical groove in length L1 and the central axis of the drill body is β1, and β1 gradually increases along the direction of the drill tip approaching the first position; the helix angle between the main helical groove in length L2 and the central axis of the drill body is β2, and β2 gradually decreases along the direction of the first position approaching the second position and then remains constant; wherein, the value range of β1 is 20°~70°, and the value range of β2 is 35°~65°.

[0013] In the drill bit described above, the apex angle α at the drill tip ranges from 90° to 150°.

[0014] As described above, the cutting length of the drill bit is L3, where L3 = L1 + L2, and the value of L3 ranges from 1mm to 20mm.

[0015] As described above, in a drill bit, the main helical groove has a width angle γ on both sides of the drill body along the length direction, and the width angle γ satisfies: 110° ≤ γ ≤ 160°.

[0016] The present invention provides a drill bit, comprising a drill body, wherein the drill diameter of the drill body is in the range of 0.01mm to 0.8mm, so as to be suitable for processing holes with a diameter of 0.01mm to 0.8mm on circuit boards. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a conventional single-flute drill bit; Figure 2 A schematic diagram illustrating the blockage of the secondary spiral groove and the wear of the main and secondary cutting edges; Figure 3 A schematic diagram of a broken drill bit and a coarse hole. Figure 4 This is a schematic diagram of the structure of an embodiment of the present invention; Figure 5 This is a structural schematic diagram corresponding to the included angle of the main spiral groove width in an embodiment of the present invention; Figure 6 This is a schematic diagram showing the helix angle between the helix of the main helical groove and the central axis of the drill body, corresponding to an embodiment of the present invention. Figure 7 This is a structural schematic diagram showing the groove width of the main spiral groove and the groove width of a single groove in an embodiment of the present invention. Figure 8 This is a structural schematic diagram of the main spiral groove core thickness and the secondary spiral groove core thickness corresponding to an embodiment of the present invention.

[0018] Figure label: 100-Drill body, 110-Drill tip, 111-Main cutting edge, 1111-Main spiral groove, 112-Secondary cutting edge, 1121-Secondary spiral groove, 200-Hole. Detailed Implementation

[0019] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0020] In the description of this application, it should be understood that if directional descriptions are involved, such as up, down, front, back, left, right, etc., indicating the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings, it is only for the convenience of describing this application and simplifying the description, and does 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, and therefore should not be construed as a limitation of this application.

[0021] In the description of this application, if words such as several, greater than, less than, exceeding, above, below, or within appear, "several" means one or more, "more than" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the number itself, and "above," "below," "within," etc. are understood to include the number itself.

[0022] In the description of this application, the use of terms such as "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0023] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0024] like Figures 1-8 As shown, an embodiment of the present invention provides a drill bit, comprising: The drill body 100 has a drill tip 110 on one side along its length. The drill tip 110 has a main cutting edge 111 and a secondary cutting edge 112. The main cutting edge 111 extends a main spiral groove 1111 on the side away from the tip of the drill tip 110, and the secondary cutting edge 112 extends a secondary spiral groove 1121 on the side away from the tip of the drill tip 110. The main spiral groove 1111 and the secondary spiral groove 1121 converge at a first position of the drill body 100 in a direction away from the drill tip 110 to form a single groove. The single groove extends to a second position of the drill body 100 in a direction away from the drill tip 110. Wherein, the length between the tip of drill tip 110 and the first position is L1, and the straight line length between the first position and the second position is L2, then the following condition is satisfied: L1≤L2.

[0025] Specifically, the drill bit also includes a drill shank, which is connected to the side of the drill body 100 away from the drill tip 110, so as to facilitate connection with drilling equipment via the drill shank.

[0026] Specifically, the L1≤L2 design ensures that the single groove has sufficient length to guide the chips out, reducing the torque increase, hole wall scratches, and drill bit breakage caused by chip accumulation in the hole, thereby improving machining quality and extending the service life of the drill bit.

[0027] Specifically, by precisely defining the value of L1, this application enables the main helical groove 1111 and the secondary helical groove 1121 to converge at the first position of the drill body 100 to form a single groove, and the single groove extends to the second position of the drill body 100 in a direction away from the drill tip 110. This effectively expands the chip removal space of the drill bit, prevents chip retention, effectively improves chip removal smoothness and efficiency, extends the service life of the drill bit, and reduces the risk of tool breakage. At the same time, by pre-determining the value of L1, it is convenient to process according to a unified standard, which improves the convenience and consistency of drill bit processing, thereby improving production efficiency.

[0028] In some embodiments, such as Figures 4-7 As shown, the drill diameter of drill body 100 is d, L1 is 1 to 5 times the drill diameter, and L2 is 15 to 80 times the drill diameter.

[0029] Specifically, L1 is 1 to 5 times the drill diameter, so that the main spiral groove 1111 and the secondary spiral groove 1121 can intersect within a shorter distance, reducing the core thickness reduction problem caused by the excessive length of the double groove section; in this embodiment, when L1 is 2 to 4 times the drill diameter, the rigidity of the drill bit can be better ensured and the drill bit's anti-breakage ability can be improved.

[0030] Specifically, L2 is 15 to 80 times the drill diameter, enabling the single groove to extend stably over a longer distance, thereby reducing the probability of chip clogging. At the same time, the single groove can cover a longer chip removal path, which is beneficial for maintaining smooth chip removal when small diameter drills are used to process deep holes or deep circuit board holes, especially suitable for processing multiple circuit boards stacked together.

[0031] Specifically, the main spiral groove 1111 and the secondary spiral groove 1121 run parallel along the length L2 to the end of the drill body 100 away from the drill tip 110. The groove lengths of the main spiral groove 1111 and the secondary spiral groove 1121 can be equal or unequal. When the groove lengths of the main spiral groove 1111 and the secondary spiral groove 1121 are unequal, the main spiral groove 1111 needs to be extended to the end of the drill body 100 away from the drill tip 110. In this embodiment, it is better when the groove lengths of the main spiral groove 1111 and the secondary spiral groove 1121 are equal, which also facilitates the improvement of processing consistency.

[0032] In some embodiments, such as Figures 4-7 As shown, the groove width of the main spiral groove 1111 in length L1 is GW1, and the groove width of the single groove in length L2 is GW2. The value of GW1 ranges from 1.5 times to 3.5 times the drill diameter, and the value of GW2 ranges from 1 times to 2.5 times the drill diameter.

[0033] Specifically, in this embodiment, when GW1 is 1.5 to 3.5 times the drill diameter, it can better meet the requirements of chip containment and chip removal in length L1, and reduce the accumulation of chips near the drill tip 110.

[0034] Specifically, in this embodiment, when GW2 is 1 to 2.5 times the drill diameter, it can better meet the requirements for chip containment and removal in length L2, while avoiding excessively wide grooves that would result in a smaller core thickness of the drill body, leading to a decrease in strength and improving the strength of the drill body.

[0035] In some embodiments, such as Figures 4-7 As shown, the core thickness of the main spiral groove 1111 near the tip of the drill tip 110 is K1, and the core thickness of the secondary spiral groove 1121 near the tip of the drill tip 110 is K2. The value of K1 ranges from 15% to 60% of the drill diameter, and the value of K2 ranges from 10% to 70% of the drill diameter. By reasonably setting K1 and K2, sufficient support strength can be provided near the main cutting edge 111 and the secondary cutting edge 112 to prevent the micro drill bit from bending or breaking during high-speed drilling and improve the reliability of the drill bit.

[0036] Specifically, core thickness is the solid material dimension in the central region of the drill bit, between the two helical grooves on the cross-section of the drill bit, to reflect how much material remains in the central part of the drill bit to withstand force and torque.

[0037] Specifically, since the main spiral groove 1111 and the secondary spiral groove 1121 are not necessarily completely symmetrical, K1 is the core thickness of the main spiral groove 1111 near the drill tip 110, and K2 is the core thickness of the secondary spiral groove 1121 near the drill tip 110; at a position about 1 mm from the drill tip 110, the core thickness of the secondary spiral groove 1121 is 50% to 130% of the core thickness of the main spiral groove 1111; at a position about 50% of the length of the drill body 100, the core thickness of the secondary spiral groove 1121 is 50% to 180% of the core thickness of the main groove; at a position about 1 mm from the end of the single groove towards the drill tip 110, the core thickness of the secondary spiral groove 1121 is 70% to 150% of the core thickness of the main groove.

[0038] Specifically, within length L2, when K1=K2, the core thickness is 25%~60% of the drill diameter; when K1>K2, the value of K1 ranges from 30%~60% of the drill diameter, and the value of K2 ranges from 20%~50% of the drill diameter; when K1<K2, the value of K1 ranges from 20%~50% of the drill diameter, and the value of K2 ranges from 30%~90% of the drill diameter. This improves the flexibility of the drill bit in different applications.

[0039] Specifically, when K1 is 25% to 50% of the drill diameter, it can better balance the chip removal capacity and stiffness of the drill body 100 in the length L1, and further improve the working stability of the drill bit.

[0040] Specifically, the core thickness near the drill tip 110 increases towards the second position. This increase can be segmented or continuous. If it is continuous, it can be linear or non-linear to improve the drill bit's resistance to breakage.

[0041] In some embodiments, the drill body 100 has a drill diameter range of 0.01mm to 0.8mm, making it suitable for machining micro-holes in circuit boards, electronic packaging holes, and small holes in precision parts. Meanwhile, the drill bit, through the combination of a double groove of length L1 and a single groove of length L2, can achieve smooth chip removal in small holes, reduce tool breakage and hole position deviation, and effectively improve hole wall quality and machining efficiency.

[0042] In some embodiments, such as Figures 4-7 As shown, the helix angle between the main helical groove 1111 in length L1 and the central axis of the drill body 100 is β1, and β1 gradually increases along the direction of the tip of the drill tip 110 towards the first position; the helix angle between the main helical groove 1111 in length L2 and the central axis of the drill body 100 is β2, and β2 gradually decreases along the direction of the first position towards the second position and then remains constant; wherein, the value range of β1 is 20°~70°, and the value range of β2 is 35°~65°.

[0043] Specifically, β1 gradually increases along the direction of the tip of the drill tip 110 towards the first position, which helps the chips to quickly enter the main spiral groove 1111 and the secondary spiral groove 1121 from the drill tip 110; β2 gradually decreases along the direction of the first position towards the second position and then remains constant, which helps to reduce the friction and blockage of chips in the single groove and improve the smoothness of chip removal from the drill bit.

[0044] Specifically, in this embodiment, the value of β1 is in the range of 35°~50°, so that the helical lines of the main helical groove 1111 and the secondary helical groove 1121 do not change too drastically, and the intersection is smoother, reducing abrupt changes in the groove shape, which is conducive to maintaining the rigidity of the drill bit near the drill tip 110 and ensuring the cutting performance of the drill bit.

[0045] Specifically, the value of β2 is in the range of 40°~55°, which is conducive to the rapid backward conveying of chips by the single groove, reducing the accumulation of chips in the hole. This not only reduces the secondary scraping of the hole wall by chips in the hole, but also reduces the cutting torque, effectively ensuring the chip removal performance of the drill bit.

[0046] Specifically, the change from β1 in length L1 to β2 in length L2 can be a piecewise change or a continuous change; if it is a continuous change, the amount of change can be linear or nonlinear, in order to improve the applicability of the drill bit.

[0047] In some embodiments, such as Figures 4-7 As shown, the apex angle α at the drill tip 110 ranges from 90° to 150°, ensuring that the drill tip 110 maintains both sufficient sharpness and good structural strength. For micro drill bits, this helps reduce entry offset and chipping, and improves hole positioning accuracy.

[0048] Specifically, in this embodiment, the apex angle α ranges from 110° to 150° to improve the resistance to tool breakage, while reducing local overheating, reducing drill bit wear, and extending the service life of the drill bit.

[0049] In some embodiments, the cutting length of the drill bit is L3, where L3 = L1 + L2, and the value of L3 ranges from 1mm to 20mm, so that the length L1 region and the length L2 region of the drill body 100 form a continuous whole, which is beneficial to maintain the integrity of the chip removal channel under small drill diameter and ensure smooth chip removal.

[0050] Specifically, the value of L3 ranges from 1mm to 20mm. During manufacturing, the cutting length can be adjusted by controlling L1 and L2 to adapt the drill bit to different processing equipment, clamping methods and drilling depth requirements. This is beneficial to improving the versatility and production efficiency of the drill bit, while also facilitating quality inspection and specification management.

[0051] In some embodiments, such as Figures 4-8 As shown, the main spiral groove 1111 has a width angle γ on both sides of the drill body 100 along the length direction. The width angle γ satisfies: 110° ≤ γ ≤ 160°, so that the main spiral groove 1111 has sufficient opening width and can maintain the strength of the groove wall structure, which is beneficial to the stable chip removal of the drill bit in high-speed drilling.

[0052] like Figures 1-8 As shown, an embodiment of the present invention provides a drill bit, including a drill body 100, the drill body 100 having a drill diameter range of 0.01mm to 0.8mm, suitable for processing holes with a diameter of 0.01mm to 0.8mm on circuit boards.

[0053] Specifically, the drilling diameter of the drill body 100 ranges from 0.01mm to 0.8mm, covering both micro-holes and conventional micro-holes. The drill body 100 adopts a micro-diameter structure, which can meet the requirements of high-density circuit boards for hole diameter accuracy, hole position accuracy, and hole wall quality, and is conducive to improving processing yield and production efficiency.

[0054] Specifically, the drill bit surface is coated with a coating, which is one of diamond coating, diamond-like coating, nitride coating or a composite coating thereof.

[0055] Specifically, when the coating is a nitride coating, the coating hardness is ≥30GPa and the thickness is ≥1.0μm, which enables the coating to more effectively resist abrasive wear, maintain the sharpness of the main cutting edge 111 and the secondary cutting edge 112, reduce the chipping of the main cutting edge 111 and the secondary cutting edge 112, and extend the service life of the drill bit.

[0056] Specifically, in this embodiment, the diamond-like carbon coating is a ta-C coating (tetrahedral amorphous carbon coating) with a friction coefficient of less than 0.1 and a thickness of ≥0.3μm. This ensures that the frictional resistance between the chips and the walls of the main spiral groove 1111 and the secondary spiral groove 1121 is significantly reduced, allowing the chips to be discharged more smoothly along the main spiral groove 1111 and the secondary spiral groove 1121, reducing the risk of blockage caused by the accumulation of chips in the main spiral groove 1111 and the secondary spiral groove 1121.

[0057] Specifically, the coating may be applied only within the main helical groove 1111 and the secondary helical groove 1121, or only on the periphery of the main cutting edge 111 and the secondary cutting edge 112, or within the main helical groove 1111 and the secondary helical groove 1121 and on the periphery of the main cutting edge 111 and the secondary cutting edge 112, or applied to the entire drill body 100, to improve the applicability of the drill bit.

[0058] Specifically, when the coating is a diamond-like carbon-nitride composite coating, the coating has the following distribution pattern: (1) The coating covers the drill body 100, the nitride coating is in direct contact with the drill body 100, and the ta-C coating covers the surface of the nitride coating.

[0059] (2) The coating covers the drill body 100. The main spiral groove 1111 and the secondary spiral groove 1121 are coated with only ta-C coating. The peripheral edges of the main cutting edge 111 and the secondary cutting edge 112, as well as the drill tip 110, are first coated with nitride coating, and then covered with ta-C coating on the surface of the nitride coating.

[0060] (3) The coating does not cover the entire drill body 100. The main spiral groove 1111 and the secondary spiral groove 1121 are coated with ta-C coating. The peripheral edges of the main cutting edge 111 and the secondary cutting edge 112 are coated with nitride coating that directly contacts the drill body 100. Then the ta-C coating is covered on the surface of the nitride coating.

[0061] (4) The coating covers the entire drill body 100. The main spiral groove 1111 and the secondary spiral groove 1121 and the drill tip 110 are coated with ta-C coating. The main cutting edge 111 and the secondary cutting edge 112 are coated with nitride coating that directly contacts the drill body 100. Then the ta-C coating is covered on the surface of the nitride coating.

[0062] This embodiment effectively improves the applicability of the drill bit by adopting the above distribution method.

[0063] The test comparison is as follows: Test 1: Comparison of drill bit and blade in this embodiment: Drill bit in this embodiment: The drill bit selected for layer-stacking efficiency improvement (in this embodiment) has a drill diameter of 0.3 mm and a drill body 100 length of 6.5 mm. The drill body 100 has a main cutting edge 111 and a secondary cutting edge 112 in the drill tip 110 region. A main helical groove 1111 and a secondary helical groove 1121 extend from the tip of the main cutting edge 111 and the secondary cutting edge 112 away from the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 converge at a first position to form a single groove, which extends along the direction away from the drill tip 110 to a second position of the drill body 100. The length of L1 is 1 mm. The core thickness of the main spiral groove 1111 in the drill tip 110 region is 0.09 mm, and the core thickness of the secondary spiral groove 1121 is 0.11 mm. In length L1, β1 is 36° and α is 130°. The length of L2 is 5.3 mm. In the second position, the core thickness of the main spiral groove 1111 is 0.255 mm, and the core thickness of the secondary spiral groove 1121 is 0.26 mm. The β2 in the second position is 45°. The change from β1 in length L1 to β2 in length L2 is linear. The core thickness near the drill tip 110 increases segmentally towards the second position.

[0064] Comparison 1: A conventional single-flute drill bit with a diameter of 0.3 mm and a drill body 100 length of 6.5 mm is selected. The drill body 100 has a main cutting edge 111 and a secondary cutting edge 112 in the drill tip 110 area. A main helical groove 1111 extends from the tip of the main cutting edge 111 away from the drill tip 110, and the secondary cutting edge 112 extends to 1.0 mm from the tip of the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 do not intersect. The main helical groove 1111 has a length of 6.5 mm, and the secondary helical groove 1112... The length of 21 is 1.0 mm. The front core thickness of the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip 110 is 0.10 mm. The front helix angle of the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip is 35°, and α is 130°. The rear core thickness of the end of the main spiral groove 1111 away from the drill tip 110 is 0.26 mm. The rear core thickness of the end of the secondary spiral groove 1121 away from the drill tip 110 is 0.125 mm. The rear helix angle of the end of the main spiral groove 1111 away from the drill tip 110 is 45°. The back helix angle of the end of the secondary helical groove 1121 away from the drill tip 110 is 35°. The change of the front helix angle and the back helix angle of the main helical groove 1111 and the secondary helical groove 1121 is segmented. The core thickness of the main helical groove 1111 increases segmentally from front to back, and the core thickness of the secondary helical groove 1121 increases segmentally from front to back.

[0065] Test information: Printed circuit board material: standard FR4 (epoxy glass cloth laminate), single board thickness 1.6mm, 3 boards stacked, total thickness 4.8mm. Test results show: ① The total porosity is reduced from 6000H (after 3 grinding cycles, 4 uses, and 1500H) compared to the conventional design. Increase from 4=6000H to 12000H (grind 3 times, use 4 times, 2500 H) 4 = 12000 H).

[0066] ②The pore size of Hole 200 is reduced from 24um to 11um compared to the conventional design.

[0067] ③ The intersection of the main spiral groove 1111 and the secondary spiral groove 1121 overcomes the problem of drill bit breakage caused by chip accumulation in the secondary spiral groove 1121, reducing the breakage rate from the original 1% to 0.01%.

[0068] ④ The hole position accuracy is improved by 0.5 compared with the conventional design, and the detection standard is ±3mil.

[0069] This embodiment solves the industry pain point of tool breakage caused by chip clogging in the secondary spiral groove 1121 of conventional single-flute drill bits by integrating the design of key structural parameters in the length L1 and length L2 regions.

[0070] Test 2: This embodiment compares drill bits coated with a wear-resistant coating with conventional white-bladed drill bits: Drill bit in this embodiment: The drill bit selected for layer enhancement and efficiency improvement has a diameter of 0.25 mm and a length of 6.2 mm for the drill body 100. The drill tip 110 region of the drill body 100 has a main cutting edge 111 and a secondary cutting edge 112. A main helical groove 1111 and a secondary helical groove 1121 extend from the tip of the main cutting edge 111 and the secondary cutting edge 112 away from the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 converge at a first position to form a single groove, which extends along the direction away from the drill tip 110 to a second position of the drill body 100. The length of L1 is 1.0 mm, and the core of the main helical groove 1111 in the drill tip 110 region... The core thickness of the secondary spiral groove 1121 is 0.095 mm, with a thickness of 0.08 mm. β1 in length L1 is 38° and α is 130°. The length of L2 is 5.2 mm. The core thickness of the main spiral groove 1111 in the second position is 0.245 mm, and the core thickness of the secondary spiral groove 1121 is 0.255 mm. β2 in the second position is 45°. The change of β1 in length L1 towards β2 in length L2 is linear. The core thickness near the drill tip 110 increases segmentally towards the second position. Furthermore, the peripheral cutting edges of the main cutting edge 111 and the secondary cutting edge 112 of this embodiment are coated with a ta-C coating.

[0071] Comparison 2: A conventional single-flute drill bit with a diameter of 0.25 mm and a drill body length of 6.2 mm is selected. The drill body 100 has a main cutting edge 111 and a secondary cutting edge 112 in the drill tip 110 area. A main helical groove 1111 extends from the tip of the main cutting edge 111 away from the drill tip 110, and the secondary cutting edge 112 extends to 0.9 mm from the tip of the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 do not intersect. The main helical groove 1111 has a length of 6.2 mm, and the secondary helical groove 1121 has a length of 0.9 mm. The front core thickness of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip 110 is 0.085 mm. The front helix angle of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip is 35°, and α is 130°. The rear core thickness of the end of the main spiral groove 1111 away from the drill tip 110 is 0.25 mm, and the rear core thickness of the end of the secondary spiral groove 1121 away from the drill tip 110 is 0.115 mm. The rear helix angle of the end of the main spiral groove 1111 away from the drill tip 110 is 45°. The rear helix angle of the end of the secondary spiral groove 1121 away from the drill tip 110 is 35°. The change in the front helix angle and the rear helix angle of the main spiral groove 1111 and the secondary spiral groove 1121 is segmented. The core thickness of the main spiral groove 1111 increases segmentally from front to rear, and the core thickness of the secondary spiral groove 1121 increases segmentally from front to rear.

[0072] Test information: Printed circuit board material: Medium TG PCB (high glass transition temperature printed circuit board), single board thickness 1.5mm, stacked 3 boards, total thickness 4.5mm. Test results show: ① The total porosity is reduced by 3000H (after 2 grinding cycles, 3 uses, and 1000) compared to the conventional design. 3=3000H) increased to 18000H (grinding 3 times, use 4 times, 4500) 4 = 18000H).

[0073] ②The pore size of Hole 200 is reduced from 22um to 15um compared to the conventional design.

[0074] ③ The intersection of the main spiral groove 1111 and the secondary spiral groove 1121 overcomes the problem of drill bit breakage caused by chip accumulation in the secondary spiral groove 1121, reducing the breakage rate from the original 1% to 0.05%.

[0075] ④ The hole position accuracy is improved by 0.5 compared with the conventional design, and the detection standard is ±3mil.

[0076] This embodiment solves the industry pain point of tool breakage caused by chip clogging in the secondary spiral groove 1121 of conventional single-flute drill bits by integrating the design of key structural parameters in the length L1 and length L2 regions.

[0077] Test 3: This embodiment compares the composite coating applied to the drill bit with a conventional white-bladed drill bit: Drill bit in this embodiment: The drill bit selected for layer enhancement and efficiency improvement has a diameter of 0.225 mm and a length of 5.0 mm for the drill body 100. The drill tip 110 region of the drill body 100 has a main cutting edge 111 and a secondary cutting edge 112. A main helical groove 1111 and a secondary helical groove 1121 extend from the tip of the main cutting edge 111 and the secondary cutting edge 112 away from the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 converge at a first position to form a single groove, which extends in a direction away from the drill tip 110 to a second position on the drill body 100. The length of L1 is 0.8 mm, the core thickness of the main helical groove 1111 in the drill tip 110 region is 0.075 mm, and the core thickness of the secondary helical groove 1121 is 0.0 mm. 90mm, β1 is 38° and α is 130° in length L1; the length of L2 is 4.2mm, the core thickness of the main spiral groove 1111 at the second position is 0.215mm, the core thickness of the secondary spiral groove 1121 is 0.235mm, and β2 at the second position is 48°; the change of β1 in length L1 towards β2 in length L2 is linear; the core thickness near the drill tip 110 increases segmentally towards the second position, and in this embodiment, a coating is used to cover the entire drill body 100, and a composite coating of diamond-like carbon coating + nitride coating is applied to the surface of the drill body 100.

[0078] Comparison 3: A conventional single-flute drill bit with a diameter of 0.225 mm and a drill body length of 5.8 mm is selected. The drill body 100 has a main cutting edge 111 and a secondary cutting edge 112 in the drill tip 110 area. A main helical groove 1111 extends from the tip of the main cutting edge 111 away from the drill tip 110, and the secondary cutting edge 112 extends to 0.9 mm from the tip of the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 do not intersect. The main helical groove 1111 has a length of 5.8 mm, and the secondary helical groove 1121 has a length of 0.9 mm. The front core thickness of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip 110 is 0.085 mm. The front helix angle of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip is 38°, and α is 130°. The rear core thickness of the end of the main spiral groove 1111 away from the drill tip 110 is 0.245 mm, and the rear core thickness of the end of the secondary spiral groove 1121 away from the drill tip 110 is 0.115 mm. The rear helix angle of the end of the main spiral groove 1111 away from the drill tip 110 is 48°. The rear helix angle of the end of the secondary spiral groove 1121 away from the drill tip 110 is 38°. The change in the front helix angle and the rear helix angle of the main spiral groove 1111 and the secondary spiral groove 1121 is segmented. The core thickness of the main spiral groove 1111 increases segmentally from front to rear, and the core thickness of the secondary spiral groove 1121 increases segmentally from front to rear.

[0079] Test information: Printed circuit board material: standard FR4, single board thickness 1.9mm, 2 stacked boards, total thickness 3.8mm. Test results show: ① The total porosity is reduced from 4500H (after 2 grinding cycles and 3 uses, to 1500H) compared to the conventional design. 3=4500H) increased to 12000H (grinding 3 times, use 4 times, 3000H) 4 = 12000H).

[0080] ②The pore size of Hole 200 is reduced from 24um to 9um compared to the conventional design.

[0081] ③ The intersection of the main spiral groove 1111 and the secondary spiral groove 1121 overcomes the problem of drill bit breakage caused by chip accumulation in the secondary spiral groove 1121, reducing the breakage rate from the original 0.5% to 0.005%.

[0082] ④ The hole position accuracy is improved by 0.6 compared to the conventional design, and the detection standard is ±3mil.

[0083] This embodiment solves the industry pain point of tool breakage caused by chip clogging in the secondary spiral groove 1121 of conventional single-flute drill bits by integrating the design of key structural parameters in the length L1 and length L2 regions.

[0084] Test 4: This embodiment compares the composite coating applied to the drill bit with a conventional white-bladed drill bit: Drill bit in this embodiment: The drill bit selected for layer enhancement and efficiency improvement has a drill diameter of 0.50 mm and a drill body 100 length of 7.0 mm. The drill tip 110 region of the drill body 100 has a main cutting edge 111 and a secondary cutting edge 112. A main helical groove 1111 and a secondary helical groove 1121 extend from the tip of the main cutting edge 111 and the secondary cutting edge 112 away from the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 converge at a first position to form a single groove, which extends in a direction away from the drill tip 110 to a second position of the drill body 100. The length of L1 is 1.5 mm, the core thickness of the main helical groove 1111 in the drill tip 110 region is 0.135 mm, and the core thickness of the secondary helical groove 1121 is 0. The length of L1 is 155mm, with β1 being 35° and α being 130°. The length of L2 is 5.5mm. The core thickness of the main spiral groove 1111 at the second position is 0.39mm, the core thickness of the secondary spiral groove 1121 is 0.42mm, and the β2 at the second position is 45°. The change of β1 in length L1 towards β2 in length L2 is linear. The core thickness near the drill tip 110 increases segmentally towards the second position. In this embodiment, a composite coating of diamond-like carbon coating and nitride coating is applied to the surface of the drill body 100, covering the entire drill body 100.

[0085] Comparison 4: A conventional single-flute drill bit with a diameter of 0.45 mm and a drill body 100 length of 7.0 mm is selected. The drill body 100 has a main cutting edge 111 and a secondary cutting edge 112 in the drill tip 110 area. A main helical groove 1111 extends from the tip of the main cutting edge 111 away from the drill tip 110, and the secondary cutting edge 112 extends to 1.2 mm from the tip of the drill tip 110. The main helical groove 1111 and the secondary helical groove 1121 do not intersect. The main helical groove 1111 has a length of 7.0 mm, and the secondary helical groove 1121 has a length of 1.2 mm. The front core thickness of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip 110 is 0.145 mm. The front helix angle of both the main spiral groove 1111 and the secondary spiral groove 1121 near the drill tip is 35°, and α is 130°. The rear core thickness of the end of the main spiral groove 1111 away from the drill tip 110 is 0.405 mm, and the rear core thickness of the end of the secondary spiral groove 1121 away from the drill tip 110 is 0.155 mm. The rear helix angle of the end of the main spiral groove 1111 away from the drill tip 110 is 45°. The change in the front helix angle and the rear helix angle of the main spiral groove 1111 and the secondary spiral groove 1121 is segmented. The core thickness of the main spiral groove 1111 increases segmentally from front to rear, and the core thickness of the secondary spiral groove 1121 increases segmentally from front to rear.

[0086] Test information: Printed circuit board material: standard FR4, single board thickness 1.8mm, 3 stacked boards, total thickness 6.4mm. Test results show: ① The total porosity is reduced from 18000H (after 3 grinding cycles, 4 uses, and 4500) compared to the conventional design. 4=18000H) increased to 40000H (grinding 4 times, use 5 times, 8000) 5 = 40000H).

[0087] ② The pore size of Hole 200 is reduced from 24um to 15um compared to the conventional design.

[0088] ③ The intersection of the main spiral groove 1111 and the secondary spiral groove 1121 overcomes the problem of drill bit breakage caused by chip accumulation in the secondary spiral groove 1121, reducing the breakage rate from the original 0.5% to 0.005%.

[0089] ④ The hole position accuracy is improved by 0.5 compared to the conventional design, and the inspection standard is ±3mil.

[0090] This embodiment solves the industry pain point of tool breakage caused by chip clogging in the secondary spiral groove 1121 of conventional single-flute drill bits by integrating the design of key structural parameters in the length L1 and length L2 regions.

[0091] In summary, by integrating the design of key structural parameters in length regions L1 and L2, and by applying a coating to the drill body 100, the industry pain point of chip clogging in the secondary spiral groove 1121 of conventional single-flute drill bits can be effectively solved, thus extending the service life of the drill bit.

[0092] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A drill bit, characterized in that, include: A drill body has a drill tip on one side along its length. The drill tip has a main cutting edge and a secondary cutting edge. The main cutting edge extends a main helical groove on the side away from the tip of the drill tip. The secondary cutting edge extends a secondary helical groove on the side away from the tip of the drill tip. The main helical groove and the secondary helical groove converge at a first position on the drill body in a direction away from the drill tip to form a single groove. The single groove extends to a second position on the drill body in a direction away from the drill tip. Wherein, the length between the tip of the drill bit and the first position is L1, and the straight line length between the first position and the second position is L2, then L1≤L2 is satisfied.

2. A drill bit according to claim 1, characterized in that, The drill diameter of the drill body is d, L1 is 1 to 5 times the drill diameter, and L2 is 15 to 80 times the drill diameter.

3. A drill bit according to claim 2, characterized in that, The main spiral groove has a groove width of GW1 in length L1, and the single groove has a groove width of GW2 in length L2. The value of GW1 ranges from 1.5 to 3.5 times the drill diameter, and the value of GW2 ranges from 1 to 2.5 times the drill diameter.

4. A drill bit according to claim 2, characterized in that, The core thickness of the main spiral groove near the tip of the drill tip is K1, and the core thickness of the secondary spiral groove near the tip of the drill tip is K2. The value of K1 ranges from 15% to 60% of the drill diameter, and the value of K2 ranges from 10% to 70% of the drill diameter.

5. A drill bit according to claim 2, characterized in that, The drill diameter range of the drill body is 0.01mm to 0.8mm.

6. A drill bit according to claim 1, characterized in that, The helix angle between the main helical groove in length L1 and the central axis of the drill body is β1, and β1 gradually increases along the direction of the drill tip towards the first position; the helix angle between the main helical groove in length L2 and the central axis of the drill body is β2, and β2 gradually decreases along the direction of the first position towards the second position and then remains constant; wherein, the value range of β1 is 20°~70°, and the value range of β2 is 35°~65°.

7. A drill bit according to claim 1, characterized in that, The apex angle α at the drill tip ranges from 90° to 150°.

8. A drill bit according to claim 1, characterized in that, The cutting length of the drill bit is L3, where L3 = L1 + L2, and the value of L3 ranges from 1mm to 20mm.

9. A drill bit according to claim 1, characterized in that, The main spiral groove has a width angle γ on both sides of the drill body along the length direction, and the width angle γ satisfies: 110° ≤ γ ≤ 160°.

10. A drill bit, characterized in that, Includes a drill body with a drill diameter ranging from 0.01 mm to 0.8 mm, suitable for processing holes with a diameter of 0.01 mm to 0.8 mm on circuit boards.

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