Combined wood drill bit and method of manufacturing the same

Abstract

The application discloses a combined woodworking drill bit and a manufacturing method thereof, and stable assembly of a drill head and a drill seat is realized through a plug-in positioning and welding fixing mode; a cylindrical plug-in block is arranged at the bottom of the drill head; the plug-in block is accurately plugged into a slot of the drill seat; and the drill head and the drill seat are welded after upper chip removal grooves of the drill head are overlapped with lower chip removal grooves of the drill seat; the drill head is arranged with three cutting edges, a positioning tip is formed at the center of the cutting edges, the cutting edges are arranged with arc-shaped curved surfaces, and a breaking tip is arranged at the end of the cutting edges; the breaking tip can be matched with the positioning tip to pre-position a drilling position and prevent the drill bit from deviating; the cutting edges are integrally arranged with a hard alloy pressing structure, the integrally arranged hard alloy pressing structure can guarantee the butt joint precision of the cutting edges and the drill seat; a thinning groove is arranged on one side of the upper chip removal grooves of the cutting edges, the thinning groove can reduce the contact between the cutting edges and wood, and the thinning groove can assist in heat dissipation of the drill head; the upper chip removal grooves are overlapped with the lower chip removal grooves of the drill seat, and smooth chip removal is realized.

Description

Technical Field

[0001] This invention belongs to the field of woodworking drill bit processing technology, specifically relating to a combined woodworking drill bit and its manufacturing method. Background Technology

[0002] In woodworking, drill bits are essential tools for drilling holes in wood, and their performance directly affects drilling accuracy and work efficiency. Traditional woodworking drill bits are mostly one-piece structures, with the drill head and tool holder molded as a single unit. While this structure is relatively stable, over long-term drilling operations, the cutting edge will lose its cutting performance due to wear and chipping. At this point, the entire drill bit must be replaced, resulting in a waste of resources for unworn parts such as the tool holder, significantly increasing the material costs of woodworking. Furthermore, existing drill bits often have straight cutting edges, which experience greater resistance during machining, leading to significant tool vibration and a higher risk of chipping. Additionally, ensuring a long tool life requires high-hardness cemented carbide materials, which are expensive, further increasing the cost of one-piece drill bits.

[0003] Many existing assembled drill bits use threaded connections or snap-fit ​​structures to assemble the drill bit and the tool holder. During high-speed rotation, these connection methods are prone to loosening and misalignment due to vibration, affecting drilling accuracy. Furthermore, the presence of threaded or snap-fit ​​structures occupies the connection space between the drill bit and the tool holder, limiting the design layout of the upper and lower chip removal grooves, resulting in poor chip removal and causing problems such as excessively high chip temperature and rough wood drilling surface.

[0004] Therefore, it is necessary to develop a split-type woodworking drill bit that is stable in assembly, smooth in chip removal, cost-controllable, and has excellent chip-cutting performance in order to solve the relevant technical problems of existing woodworking drill bits. Summary of the Invention

[0005] The purpose of this invention is to provide a combined woodworking drill bit and its manufacturing method. Stable assembly of the drill bit and the drill holder is achieved through plug-in positioning and welding. A cylindrical plug-in block is provided at the bottom of the drill bit, which precisely plugs into the slot of the drill holder. The upper chip removal groove of the drill bit and the lower chip removal groove of the drill holder are overlapped and then welded together. The drill bit has a three-blade layout, with a positioning tip at the center of the blade. The cutting edge is an arc-shaped curved surface, and a breaking tip is provided at the end of the blade. This tip can cooperate with the positioning tip to pre-position the drilling position and prevent the drill bit from deviating, effectively cutting wood fibers. The blade is a one-piece structure pressed from hard alloy, resulting in a more compact overall structure, superior rigidity, and larger chip removal space, while ensuring the alignment accuracy between the blade and the drill holder. A thinning groove is provided on the blade on one side of the upper chip removal groove, which reduces the contact between the blade and the wood and assists in heat dissipation. The upper chip removal groove and the lower chip removal groove of the drill holder overlap vertically, achieving smooth chip removal.

[0006] This invention is achieved through the following technical solution: A combined woodworking drill bit includes a drill head and a drill holder. The bottom of the drill head has a connecting surface, and at least one plug-in block is provided on the connecting surface. The drill holder has a mounting surface, and a corresponding slot is provided on the mounting surface. The plug-in block and the slot are engaged to position the drill head. The drill head and the drill holder are welded together. The drill head has multiple sets of cutting edges, and an upper chip removal groove is provided between adjacent cutting edges. The drill holder has a corresponding lower chip removal groove. The upper and lower chip removal grooves overlap to form multiple combined chip removal grooves.

[0007] Preferably, the cutting edge of each blade is an arc-shaped curved surface structure, and the curvature of each blade is the same.

[0008] Preferably, the centers of the multiple blades are connected to form a positioning tip; each group of blades is provided with a combined back face, the inclination angle of the combined back face being 3°-25°.

[0009] Preferably, the combined back face includes two first back faces connected to the cutting edge and two second back faces away from the cutting edge; the two first back faces are respectively located on both sides behind the cutting edge, and are smoothly connected at the end closest to the cutting edge; the two second back faces are respectively disposed behind the two first back faces, and are smoothly connected at the end away from the cutting edge; the inclination angle of the first back face is smaller than the inclination angle of the second back face.

[0010] Preferably, a thinning groove is provided on the blade behind the combined back face. The thinning groove can reduce the frictional resistance between the blade and the wood and is used for heat dissipation of the blade tip.

[0011] Preferably, the thinning groove is located on one side edge of the upper chip outlet groove and is configured as a beveled structure.

[0012] Preferably, a breaking tip is provided at the outer end of the thinning groove behind the cutting edge. The breaking tip is used to prevent the drill bit from deviating and to break the wood fibers.

[0013] Preferably, the outer surface of the blade has an arc-shaped structure.

[0014] Preferably, the diameter of the connecting surface on the cutter head is larger than the diameter of the mounting surface on the cutter holder.

[0015] A method for manufacturing a modular woodworking drill bit, comprising the following steps: S1: The cutter head is manufactured using powder metallurgy pressing technology; S2: A slot is machined on the mounting surface of the tool holder; S3: Insert the connector block of the cutter head into the slot, adjust the assembly angle between the cutter head and the tool holder, and make the upper chip groove of the cutter head coincide with the lower chip groove of the tool holder before welding the cutter head.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: In this invention, the cutting edge of the tool has an arc-shaped curved surface structure, which reduces the cutting resistance with the wood when the tool rotates. A thinning groove is also provided behind the combined back face of the cutting edge. The thinning groove can save cemented carbide material and improve the impact resistance and vibration resistance of the cutting edge. The thinning groove can reduce the friction between the back face of the cutting edge and the wood, improve the heat dissipation effect of the cutting head, and avoid the cutting head being damaged by excessive temperature due to cutting heat. At the same time, the thinning groove can reduce the difficulty of machining, improve the stability of the frame structure, and save material costs.

[0017] 2) In this invention, the combined back face design can significantly improve the service life of the cutting head. The small-angle first back face, close to the cutting edge, has an inclination angle of 3° relative to the cutting edge, which can ensure the rigidity of the cutting edge, enhance impact resistance, and is suitable for the force requirements of woodworking drills when frequently cutting into wood, reducing the risk of cutting edge breakage. The large-angle second back face, far from the cutting edge, has an inclination angle of 25° relative to the cutting edge, which can significantly reduce the contact area between the back face and the wood, reduce frictional resistance and cutting heat, and improve chip removal smoothness. As the main wear area, the small-angle design of the first back face increases the allowance for regrinding and extends the total service life of the tool. The large-angle design of the second back face results in a relatively slow wear rate, which can maintain a good chip removal channel for a long time and reduce tool blockage and overheating damage caused by poor chip removal.

[0018] 3) In this invention, by improving the structure of the cutting head and the cutting edge, the smoothness of chip drilling can be significantly improved. The cutting head is made of cemented carbide material by pressing and sintering, and the tool holder can be a finished tool holder made of ordinary metal material. It is highly practical. The tool processed by this method can significantly save the cost of cemented carbide material while ensuring the strength and service life of the cutting edge. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the overall structure of the drill bit in this invention.

[0021] Figure 2 This is a schematic diagram of the cutter head in this invention.

[0022] Figure 3 This is a schematic diagram of the tool holder structure in this invention.

[0023] Wherein: 1-cutter head, 11-positioning tip, 12-upper chip groove, 2-cutting edge, 21-cutting edge, 22-combined flank face, 221-first flank face, 222-second flank face, 23-thinning groove, 24-connecting block, 3-breaking tip, 4-tool holder, 41-lower chip groove, 42-mounting surface, 43-slot. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. Example 1:

[0025] A combination woodworking drill bit, such as Figure 1 , Figure 2 and Figure 3 As shown, the device includes a cutter head 1 and a cutter holder 4. The bottom of the cutter head 1 has a connecting surface, which is planar. A plug-in block 24, which is cylindrical, is located at the geometric center of the connecting surface. The cutter holder 4 has a mounting surface 42, on which a corresponding slot 43 is provided. The plug-in block 24 and the slot 43 are engaged to position the cutter head 1. The cutter head 1 and the cutter holder 4 are welded together. The cutter head 1 has three sets of cutting edges 2, with an included angle of 120° between them. An upper chip discharge groove 12 is provided between adjacent cutting edges 2, and a corresponding lower chip discharge groove 41 is provided on the cutter holder 4. The upper chip discharge groove 12 and the lower chip discharge groove 41 overlap to form a combined chip discharge groove. During the drilling process, the sawdust is discharged through the combined chip discharge groove.

[0026] Each cutting edge 21 of the cutting edge 2 has an arc-shaped curved surface structure, and the curvature of each cutting edge 2 is the same. The arc-shaped curved surface of the cutting edge 21 creates a progressive cutting effect with the wood, which can significantly reduce cutting resistance. In the initial stage of drilling, the contact area between the cutting edge 21 and the wood gradually increases from point to surface, achieving progressive entry. Compared with the instantaneous full contact of the straight cutting edge 21, this can reduce cutting resistance and reduce drill runout and vibration. During the cutting process, the arc-shaped cutting edge 21 will cause the wood chips to naturally form a spiral curl. Compared with the sheet-like or strip-like wood chips produced by the straight cutting edge 21, the spiral chips are easier to be discharged through the chip groove, avoiding blockage of the drill bit. The spiral chips have less friction on the hole wall, which can effectively reduce the drilling temperature.

[0027] Multiple cutting edges 2 are connected at their centers to form a positioning tip 11. Each set of cutting edges 2 is provided with a combined back face 22, and the inclination angle of the combined back face 22 is 3°-25°.

[0028] The combined flank face 22 includes two first flank faces 221 connected to the cutting edge 21 and two second flank faces 222 away from the cutting edge 21. The two first flank faces 221 are located on both sides behind the cutting edge 21 and are smoothly connected at the end near the cutting edge 21. The inclination angle of the first flank face 221 relative to the cutting edge 21 is 3°. The two second flank faces 222 are respectively located behind the two first flank faces 221 and are smoothly connected at the end away from the cutting edge 21. The inclination angle of the second flank face 222 relative to the cutting edge 21 is 25°. The inclination angle of the first flank face 221 is smaller than the inclination angle of the second flank face 222.

[0029] The small angle of the first flank face 221 ensures the rigidity of the cutting edge 21, enhances its impact resistance, and is suitable for the force requirements of woodworking drills when frequently cutting into wood, reducing the risk of chipping of the cutting edge 21. As the main wear area, the small angle design of the first flank face 221 increases the allowance for resharpening, extending the overall service life of the tool. The second flank face 222 significantly reduces the contact area between the flank face and the wood, reducing frictional resistance and cutting heat, and improving chip removal smoothness. The large angle design of the second flank face 222 results in a relatively slow wear rate, maintaining a good chip removal channel for a long time and reducing tool blockage and overheating damage caused by poor chip removal.

[0030] A thinning groove 23 is provided on the cutting edge 2 behind the combined flank face 22. The thinning groove 23 reduces the frictional resistance between the cutting edge 2 and the wood, and also serves to dissipate heat from the cutting head 1. By reducing the contact area between the flank face and the wood, the thinning groove 23 reduces cutting frictional resistance, making the drilling process smoother. Especially when machining hardwood or deep holes, it can significantly reduce the motor load and increase drilling speed. The air channel formed by the thinning groove 23 can accelerate the dissipation of cutting heat, lowering the tool's operating temperature and effectively reducing tool wear and softening caused by overheating, thus extending tool life. The design of the thinning groove 23 optimizes the stress distribution of the tool, reduces vibration and noise during drilling, improves the roundness and dimensional accuracy of the drilled hole, and reduces the risk of tool breakage.

[0031] The thinning groove 23 is located on one side edge of the upper chip removal groove 12 and is set as a bevel structure. The bevel structure is mainly used to disperse the stress of the cutting edge 2 to improve the fracture resistance of the cutting edge 2. The angle between the bevel and the bottom of the thinning groove 23 is 35°. The bevel structure can disperse and transmit the cutting force along the bevel direction, avoid stress concentration at the root of the cutting edge 21, and reduce the risk of the cutting edge 2 breaking. At the same time, it can prevent wood chips from accumulating in the thinning groove 23 and affecting the rotational balance of the tool.

[0032] A breaking tip 3 is provided at the outer end of the thinning groove 23 behind the cutting edge 2. The breaking tip 3 is used to prevent the drill bit from deviating. The height of the top of the breaking tip 3 is less than the height of the top of the positioning tip 11. The breaking tip 3 and the positioning tip 11 cooperate to form a dual positioning system. The positioning tip 11 is used for the initial positioning of the tool, and the breaking tip 3 is used to break the surface of the wood to form the tool entry point on the surface of the wood. The combination of the breaking tip 3 and the positioning tip 11 can reduce the amount of deviation during the drilling process and effectively prevent the drill bit from slipping and deviating on the surface of complex materials such as hardwood and knots. It is especially suitable for direct drilling scenarios without pre-drilling.

[0033] The outer surface of the cutting edge 2 has an arc-shaped structure. The diameter of the connecting surface on the cutting head 1 is larger than the diameter of the mounting surface 42 on the tool holder 4. During drilling, this allows the circumferential sidewall of the tool holder 4 to maintain a gap with the machining hole in the wood, avoiding direct friction between the tool holder 4 and the hole wall. This significantly reduces cutting resistance, decreases motor load, and increases drilling speed. Simultaneously, the gap between the tool holder 4 and the hole wall creates an additional chip removal channel, which can accommodate more wood chips. Especially in deep hole drilling, this effectively prevents wood chip blockage. Furthermore, air can enter the drilling cavity through the gap, accelerating the dissipation of cutting heat and reducing the tool's operating temperature. Example 2:

[0034] A method for manufacturing a modular woodworking drill bit, such as Figure 1 , Figure 2 and Figure 3 As shown, when manufacturing the above-mentioned combined woodworking drill bit, the drill head 1 is first manufactured using a powder metallurgy pressing process. The raw material for the drill head 1 is tungsten carbide (WC)-cobalt (Co) series cemented carbide powder. After the raw material is uniformly mixed by a powder mixing device, it is loaded into a high-precision mold. A servo forming machine is used for pressing to ensure uniform density of the blank. Subsequently, it is sintered in a vacuum sintering furnace at a temperature of 1400-1450℃. After sintering, it undergoes deep cryogenic treatment to ensure that the hardness and bending strength of the drill head 1 meet the standards. The complex structures on the drill head 1, such as the thinning groove 23, the combined back face 22, and the arc-shaped cutting edge 21, are all pre-machined in the mold and do not require subsequent secondary processing.

[0035] Traditional woodworking drills are limited by the difficulty of the processing technology. In addition, the rake face of traditional woodworking drills is a planar structure, resulting in poor cutting resistance and chip removal. However, the combined woodworking drill in this embodiment of the invention uses an alloy pressing blank to design the rake face into a complex helical curved surface, thereby significantly improving chip removal capability and reducing cutting resistance and cutting heat.

[0036] The semi-finished tool holder 4 is made of low-to-medium carbon steel, commonly 45# steel. The semi-finished tool holder 4 is fixed on a fixture, and a slot 43 is machined on the tool holder 4 using a CNC machine tool. The tool head 1 is inserted and positioned into the tool holder 4. The upper chip groove 12 of the tool head 1 is rotated and adjusted so that the upper chip groove 12 aligns with the lower chip groove 41, and the position is fixed with a special clamp. Then, high-frequency welding is used to connect the two into a whole. After welding, stress-relieving annealing is performed to avoid thermal deformation. After welding, the weld joint needs to be ground smooth to avoid affecting drilling accuracy. Other parts of this embodiment are the same as those in the above embodiment and will not be repeated here.

[0037] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., used to indicate the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of this invention is usually placed in during use. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0038] Furthermore, the use of terms such as "horizontal" and "vertical" in the description of this invention does not imply that the components are required to be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0039] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A combined woodworking drill bit, characterized in that, The tool includes a cutting head and a tool holder. The cutting head has a connecting surface at its bottom, and at least one plug-in block is provided on the connecting surface. The tool holder has a mounting surface, and a corresponding slot is provided on the mounting surface. The plug-in block and the slot are plugged in and engaged to position the cutting head. The cutting head and the tool holder are welded together. The cutting head has multiple sets of cutting edges, and an upper chip removal groove is provided between adjacent cutting edges. The tool holder has a corresponding lower chip removal groove. The upper and lower chip removal grooves overlap to form multiple combined chip removal grooves.

2. The combined woodworking drill bit as described in claim 1, characterized in that, Each blade has an arc-shaped curved surface, and the curvature of each blade is the same.

3. The combined woodworking drill bit as described in claim 1, characterized in that, The centers of multiple blades are connected to form a positioning tip; each set of blades is provided with a combined back face, the inclination angle of which is 3°-25°.

4. The combined woodworking drill bit as described in claim 3, characterized in that, The combined back face includes two first back faces connected to the cutting edge and two second back faces away from the cutting edge; the two first back faces are located on both sides behind the cutting edge and are smoothly connected at the end closest to the cutting edge; the two second back faces are respectively located behind the two first back faces and are smoothly connected at the end away from the cutting edge; the inclination angle of the first back face is smaller than the inclination angle of the second back face.

5. The combined woodworking drill bit as described in claim 3, characterized in that, A thinning groove is provided on the blade behind the combined back face. The thinning groove can reduce the frictional resistance between the blade and the wood and is used for heat dissipation of the blade tip.

6. The combined woodworking drill bit as described in claim 5, characterized in that, The thinning groove is located on one side edge of the upper chip outlet groove and is designed with a sloping structure.

7. The combined woodworking drill bit as described in claim 5, characterized in that, A breaking tip is provided at the outer end of the thinning groove behind the cutting edge. The breaking tip is used to prevent the drill bit from deviating and to break the wood fibers.

8. The combined woodworking drill bit as described in claim 5, characterized in that, The outer surface of the blade has an arc-shaped structure.

9. The combined woodworking drill bit as described in claim 1, characterized in that, The diameter of the connecting surface on the cutter head is larger than the diameter of the mounting surface on the cutter holder.

10. A method for manufacturing a combined woodworking drill bit, characterized in that, Manufacturing the combined woodworking drill bit as described in any one of claims 1-9 includes the following steps: S1: The cutter head is manufactured using powder metallurgy pressing technology; S2: A slot is machined on the mounting surface of the tool holder; S3: Insert the connector block of the cutter head into the slot, adjust the assembly angle between the cutter head and the tool holder, and make the upper chip groove of the cutter head coincide with the lower chip groove of the tool holder before welding the cutter head.

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