A shaped drill bit

Abstract

The utility model discloses a kind of forming drill bits, drill bit includes sequentially connected drill handle, drill rod and drill needle, the front end of the drill needle is equipped with cutting part, the outer peripheral surface of the drill needle rear of cutting part is equipped with at least one hole wall roughening structure, the hole wall roughening structure is the convex structure around the outer peripheral surface of the drill needle, and the circumferential direction of the hole wall roughening structure is equipped with by the discontinuous notch formed by the helical shape of the drill needle is arranged cutting groove truncation. The drill bit can realize drilling and hole wall roughening simultaneously, improve efficiency and plastic adhesion, ensure processing stability and service life.

Description

Technical Field

[0001] This utility model belongs to the field of machining tool technology, and specifically relates to a forming drill bit. Background Technology

[0002] Drill bits are a general term for cutting tools used to drill through holes or blind holes in solid materials, and to enlarge existing holes. Common types include twist drills, flat drills, deep hole drills, reamers, and center drills.

[0003] A Chinese utility model patent with publication number CN 222001969 U discloses a shaped groove twist drill bit, including a shank. One end of the shank is fixedly connected to a drill rod, and one end of the drill rod is provided with a drill tip cutting edge. The surface of the drill rod is provided with a spiral-shaped backing that extends to the surface of the drill tip cutting edge. The backing and the surface of the drill rod form a spiral chip-removing groove, which also extends to the surface of the drill tip cutting edge. The cross-section of the chip-removing groove is a concave semi-circular shape that tapers towards the center of the drill rod. This shaped groove twist drill bit can improve chip-breaking performance and effectively enhance chip breaking and removal.

[0004] However, after drilling with this type of drill bit, the surface of the hole wall is too smooth, making it difficult to treat the hole wall surface. Especially during the injection molding process after drilling, the plastic is difficult to adhere to the hole wall.

[0005] Therefore, it is particularly important to design and manufacture a shaped drill bit that can overcome the above problems. Utility Model Content

[0006] This utility model aims to provide a shaped drill bit that, by setting a protruding structure with specific parameters on the outer peripheral surface of the cutting part, simultaneously roughens the inner wall of the hole during the drilling process, facilitating the treatment of the workpiece hole wall. The drilling and roughening treatment can be completed in one operation with this drill bit without additional processes, while ensuring the strength and chip removal performance of the drill bit, thereby solving the technical problems and defects existing in the prior art.

[0007] This invention proposes a shaped drill bit, comprising a drill shank, a drill rod, and a drill bit connected in sequence. The drill bit has a cutting section at its front end, and at least one hole wall roughening structure is provided on the outer circumferential surface of the drill bit behind the cutting section. The hole wall roughening structure is a raised structure surrounding the outer circumferential surface of the drill bit, and the circumferential direction of the hole wall roughening structure has intermittent notches formed by the spiral chip removal grooves of the drill bit. This shaped drill bit, through the surrounding raised structure behind the cutting section of the drill bit, simultaneously roughens the inner wall of the hole during drilling, eliminating additional steps; the intermittent notches optimize chip removal, ensuring smooth processing, improving efficiency, and enhancing the adhesion of subsequent hole wall treatments.

[0008] Preferably, the roughened hole wall structure is integrally formed with the drill bit. This strengthens the connection between the two, prevents them from falling off during processing due to stress, ensures a stable roughening effect, and extends the overall service life of the drill bit.

[0009] Preferably, the axial distance between the protrusion and the tip of the cutting part is 75%-85% of the diameter of the cutting part. This avoids the main cutting area of ​​the cutting part to prevent interference with cutting accuracy, and also forms effective roughening on the hole wall to meet the machining depth requirements.

[0010] Preferably, the diameter of the protrusion is 1.05-1.15 times the diameter of the cutting part. This size design allows the protrusion to moderately compress the hole wall to form a rough texture, avoiding excessive deformation of the hole wall or a surge in drill torque due to an excessively large diameter, thus ensuring machining stability.

[0011] Preferably, the cross-sectional shape of the protrusion structure is a cone with a flat top. The cone shape facilitates embedding into the hole wall to form deep roughness marks, while the flat top reduces wear on the protrusion tip, balancing the roughening effect with structural durability.

[0012] More preferably, the width of the plane is within the range of 0.01-0.02 mm. This dimension ensures the strength of the protrusion top, preventing breakage due to stress concentration during processing, and also allows the micro-plane to form a uniform rough texture through contact with the hole wall, improving the adhesion of the plastic during the injection molding process after drilling.

[0013] More preferably, the angle of the cone is 60°±1°. This angle allows the protrusion to effectively cut into the material to form a distinct roughening texture, while avoiding an angle that is too small, resulting in a fragile and easily broken structure, or an angle that is too large, reducing the roughening effect, thus ensuring machining quality and tool life.

[0014] Preferably, the connection between the protrusion structure and the outer circumference of the drill bit is achieved through a rounded corner, with the radius R of the rounded corner not exceeding 0.02 mm. This reduces stress concentration and prevents breakage at the root of the protrusion, while the small radius rounded corner avoids weakening the roughening effect, ensuring structural strength and processing reliability.

[0015] Preferably, the groove width ratio of the formed drill bit is taken in the range of 1.4-1.8, and the groove width is taken in the range of 0.165-0.175mm. This combination of parameters can ensure unobstructed chip removal channels, balance drill bit rigidity and chip removal efficiency, avoid the impact of protruding structure settings on processing stability, and ensure continuous and efficient operation.

[0016] Preferably, the core thickness taper of the formed drill bit is 0.02 / 1. That is, for every 1mm increase in axial length, the core thickness increases by 0.02mm. This design can balance the rigidity and elasticity of the drill bit, avoid local strength deficiency caused by the addition of the protruding structure, and ensure bending resistance and machining accuracy during drilling.

[0017] Compared with the prior art, the beneficial results of this utility model are as follows:

[0018] The protruding structure behind the cutting part enables simultaneous drilling and hole wall roughening, eliminating extra steps and significantly improving processing efficiency. The protruding structure is designed to adapt to drill bit parameters, combined with integrated molding process and detailed optimization, ensuring smooth chip removal, drill bit strength and durability, and forming a uniform and effective rough surface. This greatly enhances the adhesion of plastic to the hole wall during subsequent injection molding after drilling, making it widely applicable and highly practical. Attached Figure Description

[0019] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments and, together with the description, serve to explain the principles of the present invention. Other embodiments and many anticipated advantages of the embodiments will be readily recognized as they become better understood through reference to the following detailed description. Elements in the drawings are not necessarily to scale. The same reference numerals refer to corresponding similar parts.

[0020] Figure 1 A schematic diagram of the overall structure according to an embodiment of the present utility model is shown;

[0021] Figure 2 A front view according to an embodiment of the present utility model is shown;

[0022] Figure 3 for Figure 2 A magnified structural diagram of part A in the middle;

[0023] Figure 4 A schematic diagram showing the dimensions and structure according to a specific embodiment of the present invention is shown;

[0024] Figure 5 for Figure 4 A magnified structural diagram of part B.

[0025] The meanings of the numbers in the diagram are as follows: 1. Drill shank; 2. Drill rod; 3. Drill bit; 4. Cutting section; 5. Protruding structure. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the relevant utility model and not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings.

[0027] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] This utility model proposes a shaped drill bit. Figure 1 A schematic diagram of the overall structure of a forming drill bit according to an embodiment of the present invention is shown. Figure 2 A front view according to an embodiment of the present utility model is shown, as follows: Figure 1 and 2 As shown, the forming drill bit includes a drill shank 1, a drill rod 2, and a drill bit 3 connected in sequence. The drill bit 3 has a cutting section 4 at its front end, and at least one hole wall roughening structure on the outer circumferential surface of the drill bit 3 behind the cutting section 4. The hole wall roughening structure is a raised structure surrounding the outer circumferential surface of the drill bit 3, and the circumferential direction of the hole wall roughening structure has intermittent notches formed by the spiral chip removal grooves of the drill bit 3. This forming drill bit, through the surrounding raised structure behind the cutting section 4 of the drill bit 3, simultaneously roughens the inner wall of the hole during drilling, eliminating additional steps; the intermittent notches optimize chip removal, ensuring smooth processing, improving efficiency, and enhancing the adhesion of subsequent hole wall treatments.

[0029] The roughened hole wall structure is integrally formed with the drill bit 3. This strengthens the connection between the two, prevents them from falling off due to stress during machining, ensures stable roughening effect, and extends the overall service life of the drill bit.

[0030] Specifically, Figure 3 for Figure 2 An enlarged structural diagram of part A is shown below. Figure 2 and 3 As shown, the cross-sectional shape of the protrusion structure 5 is a cone with a flat top. The width of the flat surface is within the range of 0.01-0.02 mm. The cone shape facilitates embedding into the hole wall to form deep roughness marks, while the flat top reduces wear on the protrusion tip, balancing the roughening effect with structural durability. The width of this flat surface ensures the strength of the protrusion top, preventing breakage due to stress concentration during processing, and also allows for the formation of a uniform rough texture through contact with the hole wall via the micro-plane, improving the adhesion of the plastic during the injection molding process after drilling.

[0031] Furthermore, the angle of the cone is 60°±1°. This angle allows the protrusion to effectively cut into the material to form a distinct roughening texture, while avoiding an angle that is too small, resulting in a fragile and easily broken structure, or too large, reducing the roughening effect, thus ensuring machining quality and tool life.

[0032] The connection between the protruding structure 5 and the outer circumference of the drill bit 3 is achieved through a fillet, with a radius R not exceeding 0.02 mm. This reduces stress concentration and prevents breakage at the root of the protrusion. Simultaneously, the small radius fillet avoids weakening the roughening effect, ensuring structural strength and machining reliability.

[0033] In other embodiments, the cross-sectional shape of the protrusion structure 5 can also be triangular, rectangular, trapezoidal, or arc-shaped. Different shapes can adapt to different roughness requirements; triangles are conducive to forming deeper marks, while arcs are more likely to guide chip removal. The maximum height of the protrusion structure 5 is 0.01–0.05 mm. This range can effectively roughen the hole wall by moderately protruding, while avoiding damage to the protrusion or interference with normal cutting and chip removal of the drill bit due to excessive height.

[0034] In one specific embodiment, the cross-sectional shape of the protrusion structure 5 is triangular (serrated), the maximum height of the protrusion is 0.02 mm, the tooth tip width is 0.02 mm, the axial spacing between adjacent protrusions is 0.3 mm, and the spacing is evenly distributed along the axial direction of the drill bit 3. The outer diameter of the protrusion structure 5 is 0.46 mm, which is smaller than the maximum outer diameter of the drill bit 3.175 mm, to avoid excessive interference with the hole wall during machining.

[0035] Specifically, the diameter of the protrusion 5 is 1.05-1.15 times the diameter of the cutting part 4. This size design allows the protrusion to moderately compress the hole wall, forming a rough texture, avoiding excessive deformation of the hole wall or a surge in drill torque due to an excessively large diameter, thus ensuring machining stability. The axial distance between the protrusion 5 and the tip of the cutting part 4 is 75%-85% of the diameter of the cutting part 4. This avoids the main cutting area of ​​the cutting part to prevent interference with cutting accuracy, while also effectively roughening the hole wall to meet machining depth requirements.

[0036] In one specific embodiment, the protruding structure 5 and the drill bit 3 are integrally formed using a laser cladding process. The drill bit 3 substrate is YG8 cemented carbide (hardness HRA89), and the protruding structure 5 is a tungsten carbide reinforcing layer (hardness HRA93), with a higher hardness than the substrate, ensuring wear resistance. Because the drill bit 3 has a spiral chip removal groove, the circumference of the protruding structure 5 is interrupted by the chip removal groove to form an intermittent notch with a width of 0.1 mm, which guides the chips to quickly enter and be discharged from the chip removal groove.

[0037] Furthermore, the groove ratio of the shaped drill bit is taken within the range of 1.4-1.8, and the groove width is taken within the range of 0.165-0.175mm. This combination of parameters ensures unobstructed chip removal channels, balances drill bit rigidity and chip removal efficiency, avoids the impact of raised structures on machining stability, and ensures continuous and efficient operation. The core thickness taper of the shaped drill bit is 0.02 / 1. That is, for every 1mm increase in axial length, the core thickness increases by 0.02mm. This design balances drill bit rigidity and elasticity, avoids insufficient local strength due to the addition of raised structures, and ensures bending resistance and machining accuracy during drilling.

[0038] In this embodiment, the drill bit has a groove width ratio of 1.6, a core thickness taper of 0.02 / 1, and a groove width (WO) of 0.17 mm. The protrusion structure 5 does not change the above parameters, ensuring unobstructed chip removal channels and drill bit strength. The protrusion structure 5 is only distributed in the effective machining section (5 mm in length) of the cutting part 4; there are no protrusions in the positioning section of the drill bit 3 and the drill shank 1.

[0039] When using this drill bit to process GU25UF aluminum alloy workpieces, the surface roughness Ra value of the inner wall of the hole is stable at 6.3μm, without the need for additional roughening process. Compared with traditional drill bit processing, it improves the adhesion of plastic. Moreover, after the drill bit has processed several holes in a row, the raised structure 5 shows no obvious wear, thus extending its service life.

[0040] In one specific embodiment, refer to 4 and Figure 5 The overall length of the drill bit is 38.1±0.1mm, the maximum outer diameter is 3.175~3.180mm, the total length of the drill rod 2 is 3.0~3.2mm, and the length of the cutting part 4, i.e. the effective machining length of the drill bit 3, is 2.5~2.7mm. The angle between the spiral chip removal groove of the drill bit 3 and the transverse axis is 30°±1°, and the tooth positioning dimension is 0.32~0.35mm.

[0041] The ratio of the trench width to the core thickness, i.e., the trench width ratio, is 1.6 ± 0.2; the rate of change of the core thickness along the axial direction, i.e., the core thickness taper, is 0.02 / 1; the trench width WO is 0.17 ± 0.005; the minute rate of change of the drill bit outer diameter along the axial direction, i.e., the range of the outer diameter taper, is 0.001 / 1 to 0.002 / 1.

[0042] The drill bit is suitable for workpieces made of aluminum alloy GU25UF. The tooth positioning dimension is 0.32 to 0.35, root cleaning is omitted, and the root radius (R) is ≤0.02.

[0043] The specific embodiments of this utility model have been described above, but the scope of protection of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the scope of protection of this utility model. Therefore, the scope of protection of this utility model should be determined by the scope of the claims.

[0044] In the description of this utility model, it should be understood that the terms "upper," "lower," "inner," "outer," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used for improvement. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. A shaped drill bit, comprising a drill shank, a drill rod, and a drill bit connected in sequence, characterized in that, The drill bit has a cutting part at its front end, and at least one hole wall roughening structure is provided on the outer peripheral surface of the drill bit behind the cutting part. The hole wall roughening structure is a protrusion structure surrounding the outer peripheral surface of the drill bit, and the hole wall roughening structure has an intermittent notch formed by the spiral cutting groove of the drill bit in the circumferential direction.

2. The forming drill bit according to claim 1, characterized in that, The roughened hole wall structure is integrally formed with the drill bit.

3. The forming drill bit according to claim 1, characterized in that, The axial distance between the protrusion and the tip of the cutting part is 75%-85% of the diameter of the cutting part.

4. The forming drill bit according to claim 1, characterized in that, The diameter of the protrusion is 1.05-1.15 times the diameter of the cutting part.

5. The forming drill bit according to claim 1, characterized in that, The cross-sectional shape of the protruding structure is a cone with a flat surface at the top.

6. The forming drill bit according to claim 5, characterized in that, The width of the plane is within the range of 0.01-0.02 mm.

7. The forming drill bit according to claim 5, characterized in that, The angle of the cone is 60°±1°.

8. The forming drill bit according to claim 1, characterized in that, The connection between the protruding structure and the outer circumference of the drill bit is made by a rounded corner, and the radius R of the rounded corner is no greater than 0.02 mm.

9. The forming drill bit according to claim 1, characterized in that, The groove width ratio of the formed drill bit is taken in the range of 1.4-1.8, and the groove width value is taken in the range of 0.165-0.175mm.

10. The forming drill bit according to claim 1, characterized in that, The core thickness taper of the shaped drill bit is 0.02 / 1.

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