A high efficiency drill for machining fiber composite materials

Abstract

The application provides a high-efficiency drill bit for processing fiber composite material, which comprises a drill tip part, a chip removal part and a shank part; the drill tip part comprises a rake face, a relief face and a chisel edge; the rake face and the relief face intersect to form a main cutting edge; and the main cutting edge comprises a straight cutting edge and a concave parabolic cutting edge connected with each other. The high-efficiency drill bit for processing fiber composite material provided by the application forms the main cutting edge by the intersection of the straight cutting edge and the concave parabolic cutting edge, can effectively disperse the cutting resistance in the process of processing products, reduce the axial component force generated in the processing process, and can quickly cut off the fibers, thereby effectively reducing the burrs and delamination on the processed products. By using the high-efficiency drill bit for processing fiber composite material provided by the application, the holes obtained by processing the fiber composite material have high surface roughness precision grade, no burrs and delamination, and the product qualification rate and the processing efficiency of the fiber composite material product processing are effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of cutting tools, in particular to a high-efficiency drill bit for machining fiber composite materials. BACKGROUND

[0002] Laminated components composed of carbon fiber composite materials and titanium alloy materials are widely used in aircraft wings and tail rudders, and a large number of riveting holes or screw holes are needed in the assembly process of the laminated components. In the drilling of these aircraft products, the best process is to simultaneously drill the required riveting holes or screw holes in the laminated components composed of carbon fiber composite materials and titanium alloy materials, which is the main means to ensure the connection strength, stiffness and safety of the laminated material components.

[0003] Drilling is an extremely important process in the assembly and machining process of carbon fiber composite parts. Since carbon fiber composite materials have the properties of brittleness, high strength, high hardness, poor heat conduction ability (the thermal conductivity coefficient is only 1 / 10-1 / 5 of austenitic stainless steel), anisotropy, and low interlayer strength, defects such as carbon fiber composite material burn, delamination, tearing and burr are easily generated under the action of cutting force during cutting, and the drill bit is easily worn, which not only makes it difficult to guarantee the hole quality, but also leads to low production efficiency. Therefore, the structure of the drill bit for machining carbon fiber composite materials needs to be further improved. SUMMARY

[0004] To solve the above-mentioned deficiencies in the prior art, the present application provides a high-efficiency drill bit for machining fiber composite materials, which comprises a drill tip part, a chip removal part and a shank part; the chip removal part is provided with a chip removal groove and a secondary cutting edge extending spirally from the drill tip part to the shank part; the drill tip part comprises a rake face, a relief face and a cross edge; the rake face and the relief face intersect to form a primary cutting edge; the primary cutting edge comprises a straight cutting edge and an inner concave parabolic cutting edge connected to each other; the straight cutting edge is located at one end of the drill tip part away from the shank part; and the inner concave parabolic cutting edge is located at one end of the drill tip part close to the shank part.

[0005] Further, the drill tip angle of the drill tip part is 60°-90°.

[0006] Further, the cross edge is in the shape of N.

[0007] Further, the first relief angle of the primary cutting edge is 8°-12°, and the second relief angle of the primary cutting edge is 24°-30°.

[0008] Further, the first relief angle of the secondary cutting edge is 8°-12°, and the second relief angle of the secondary cutting edge is 24°-30°.

[0009] Further, the surfaces of the drill tip part and the chip removal part are coated with a TiSiAl nanocomposite coating.

[0010] The high-efficiency drill bit for processing fiber composite material provided by the application is formed by intersecting straight cutting edges and concave parabolic cutting edges to form main cutting edges, which can effectively disperse cutting resistance in the process of processing products, reduce axial force generated in the processing process, and quickly cut off fibers to effectively reduce burrs and delamination on the processed products. By using the high-efficiency drill bit for processing fiber composite material provided by the application, the holes obtained by processing fiber composite material have high surface roughness precision level, and there are no burrs and delamination at the entrance and exit of the holes, effectively improving the product qualification rate and processing efficiency of fiber composite material product processing. BRIEF DESCRIPTION OF DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor under the premise of the drawings.

[0012] Figure 1 The structure diagram of the high-efficiency drill bit for processing fiber composite material provided by the application is shown in the figure.

[0013] Figure 2 The left view of the drill tip part is shown in the figure. Figure 1 The left view of the drill tip part is shown in the figure.

[0014] Figure 3 The left view of the drill tip part is shown in the figure. Figure 1 The left view of the drill tip part is shown in the figure.

[0015] Figure 4 The left view of the drill tip part is shown in the figure. Figure 1 The left view of the drill tip part is shown in the figure.

[0016] Figure 5 The left view of the drill tip part is shown in the figure. Figure 3 The left view of the drill tip part is shown in the figure.

[0017] Reference signs:

[0018] 10 drill tip part 11 rake face 12 flank face

[0019] 13 cross blade 14 main cutting edge 20 chip removal part

[0020] 21 chip removal groove 22 secondary cutting edge 30 shank part

[0021] 141 straight cutting edge 142 concave parabolic cutting edge DETAILED DESCRIPTION

[0022] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] As shown in Figures 1 to 5 , the present application provides a high-efficiency drill bit for machining fiber composite materials, which comprises a drill tip part 10, a chip removal part 20 and a shank part 30; the chip removal part 20 is provided with a chip removal groove 21 and a secondary cutting edge 22 which extend spirally from the drill tip part 10 to the shank part 30; the drill tip part 10 comprises a rake face 11, a relief face 12 and a cross edge 13; the rake face 11 and the relief face 12 intersect to form a primary cutting edge 14; the primary cutting edge 14 comprises a straight cutting edge 141 and a concave parabolic cutting edge 142 which are connected; the straight cutting edge 141 is located at one end of the drill tip part 10 away from the shank part 30; and the concave parabolic cutting edge 142 is located at one end of the drill tip part 10 close to the shank part 30.

[0025] In specific implementation, as shown in Figure 1 , the present application provides a high-efficiency drill bit for machining fiber composite materials, which is made of hard alloy as a whole, and comprises a drill tip part 10, a chip removal part 20 and a shank part 30 which are integrally and coaxially formed; as shown in Figure 1 , the chip removal part 20 is provided with a chip removal groove 21 and a secondary cutting edge 22 which extend spirally from the drill tip part 10 to the shank part 30, wherein the chip removal groove 21 is used for discharging cutting chips generated during cutting, and the secondary cutting edge 22 is used for trimming the hole wall of a hole made by the drill tip part 10 and has a certain guiding effect during cutting; as shown in Figure 4 , the first relief angle of the secondary cutting edge 22 is 8°-12°, and the second relief angle of the secondary cutting edge 22 is 24°-30°.

[0026] As shown in Figure 2 ,Figure 3 As shown in the figure, the drill tip angle of the drill tip part 10 is 60°-90°; the drill tip part 10 comprises a rake face 11, a flank face 12 and a chisel edge 13; wherein the chisel edge 13 is located at the drill tip and is in the shape of N; in this embodiment, the length of the chisel edge 13 is 0.02 times of the diameter of the drill bit, and the shorter chisel edge 13 can greatly reduce the axial force during cutting, and reduce the defects such as delamination, tearing and burr during the processing of carbon fiber composite materials; the main cutting edge 14 is formed by the intersection of the rake face 11 and the flank face 12, and the main cutting edge 14 comprises a straight cutting edge 141 and an inner concave parabolic cutting edge 142 connected thereto, wherein the straight cutting edge 141 is located at one end of the drill tip part 10 away from the shank part 30; the inner concave parabolic cutting edge 142 is located at one end of the drill tip part 10 close to the shank part 30, and the end of the inner concave parabolic cutting edge 142 away from the straight cutting edge 141 intersects with the secondary cutting edge 22; the main cutting edge 14 formed by the intersection of the straight cutting edge 141 and the inner concave parabolic cutting edge 142 can effectively disperse the cutting resistance during the processing of the product, reduce the axial force generated during the processing, and quickly cut off the fibers, thereby effectively reducing the burr and delamination on the processed product; as shown in the figure, Figure 5 As shown in the figure, the first clearance angle of the main cutting edge 14 is 8°-12°, and the second clearance angle of the main cutting edge 14 is 24°-30°.

[0027] The specific working mode of the high-efficiency drill bit for processing fiber composite materials provided by the embodiment of the present application is described as follows:

[0028] In the first stage, the chisel edge 13 contacts and extrudes the surface of the workpiece, and due to the extrusion effect of the chisel edge 13, the axial force rapidly increases; in the second stage, the straight cutting edge 141 of the main cutting edge 14 enters the workpiece and starts to cut the workpiece, and the axial force increases at a smaller amplitude; in the third stage, the inner concave parabolic cutting edge 142 of the main cutting edge 14 enters the workpiece and starts to remove burrs; in the fourth stage, the chisel edge 13 reaches the bottom of the workpiece, and since the chisel edge 13 drills away from the lower surface of the workpiece, the axial force suddenly decreases, at this time, delamination phenomenon is easily generated at the outlet of the hole, but the main cutting edge 14 formed by the intersection of the straight cutting edge 141 and the inner concave parabolic cutting edge 142 can effectively disperse the cutting resistance during the processing, and reduces the axial force generated during the processing, after the chisel edge 13 drills away from the lower surface of the workpiece, the axial force does not suddenly change, thereby reducing the generation of delamination phenomenon, and at the same time, the inner concave parabolic cutting edge 142 can quickly cut off the fibers, thereby effectively avoiding the generation of burrs on the processed product; in the fifth stage, the main cutting edge 14 drills away from the workpiece, and the secondary cutting edge 22 enters the workpiece and starts to ream the hole.

[0029] The same process parameters and hole forming mode are adopted to form holes in the carbon fiber composite material by using the high-efficiency drill for machining the fiber composite material provided in the embodiment of the application, referred to as drill 1, and a conventional drill for carbon fiber composite material on the market, referred to as drill 2. After the hole forming, the hole quality of the exit surface is measured by using an ultra-depth microscope, and the roughness of the hole wall is measured by using a roughness meter. The comparison results of drill 1 and drill 2 are specifically described as follows:

[0030] The burr of drill 2 is small when the first hole is machined, and there is slight delamination. With the increase of the number of holes, the burr increases rapidly, and the delamination also begins to intensify. The burr and delamination phenomenon are very serious when the fifth hole is machined. The average roughness value Ra of the first five holes machined by drill 2 is greater than 0.8 μm.

[0031] There is no delamination and burr when the first hole is machined by drill 1, and the quality is very good. The quality is still very good when the fifth hole is machined. The hole forming experiment is continued, and it is finally found that drill 1 can machine at least 20 high-quality holes without delamination and burr. The average roughness value Ra of the first five holes machined by drill 1 is less than or equal to 0.48 μm.

[0032] The high-efficiency drill for machining the fiber composite material provided in the embodiment of the application is formed by the intersection of the straight cutting edge and the concave parabolic cutting edge to form the main cutting edge. The cutting resistance can be effectively dispersed in the machining process, the axial component force generated in the machining process is reduced, and the fiber can be quickly cut off to effectively reduce the burr and delamination on the machined product. The holes obtained by using the high-efficiency drill for machining the fiber composite material provided in the embodiment of the application to machine the carbon fiber composite material have high surface roughness precision level, and there is no burr and delamination at the entrance and exit of the hole, thereby effectively improving the product qualification rate and machining efficiency of the carbon fiber composite material product machining.

[0033] Preferably, the surface of the drill tip 10 and the chip removal portion 20 is coated with a TiSiAl nano-composite coating. In specific implementation, the surface of the drill tip 10 and the chip removal portion 20 is coated with a TiSiAl nano-composite coating, so that it has better heat insulation performance and better wear resistance, thereby further improving the service life of the drill.

[0034] Although terms such as drill tip, rake face, flank face, chisel edge, main cutting edge, chip removal portion, chip removal groove, secondary cutting edge, shank, straight cutting edge, concave parabolic cutting edge, etc. are used more in this document, the possibility of using other terms is not excluded. The use of these terms is only for the convenience of describing and explaining the essence of the application; any kind of additional limitation is contrary to the spirit of the application.

[0035] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A high performance drill for machining fibre composite materials, comprising a tip portion (10), a chip removal portion (20) and a shank portion (30), the chip removal portion (20) being provided with chip flutes (21) and secondary cutting edges (22) which extend helically from the tip portion (10) to the shank portion (30); characterized in that: The drill tip (10) comprises a rake face (11), a flank face (12) and a chisel edge (13); the rake face (11) and the flank face (12) intersect to form a main cutting edge (14); the main cutting edge (14) comprises a straight cutting edge (141) and a concave parabolic cutting edge (142) connected; wherein the straight cutting edge (141) is located at one end of the drill tip (10) away from the shank (30); the concave parabolic cutting edge (142) is located at one end of the drill tip (10) close to the shank (30), and the end of the concave parabolic cutting edge (142) away from the straight cutting edge (141) intersects with the secondary cutting edge (22); The drill tip angle of the drill tip (10) is 60°-90°; The first clearance angle of the main cutting edge (14) is 8°-12°, and the second clearance angle of the main cutting edge (14) is 24°-30°; The chisel edge (13) is N-shaped, and the length of the chisel edge (13) is 0.02 times the diameter of the drill bit.

2. The high performance drill bit for machining fiber composite materials according to claim 1, characterized in that The first clearance angle of the secondary cutting edge (22) is 8°-12°, and the second clearance angle of the secondary cutting edge (22) is 24°-30°.

3. The high performance drill bit for machining fiber composite materials according to claim 1, characterized in that The surfaces of the drill tip (10) and the chip removal portion (20) are coated with a TiSiAl nanocomposite coating.

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