A milling tool capable of inhibiting burr formation in carbon fiber reinforced composites

Abstract

The application discloses a milling tool capable of inhibiting burrs of carbon fiber reinforced composite materials, which comprises upper and lower blade parts, the upper blade part comprises a body provided with two circumferentially distributed upper oblique blade heads mounted at the bottom end of the body, and the body is provided with a central axial hole; the lower blade part comprises a guide rod penetrating into the central axial hole and fixed with the body and capable of being adjusted in axial position; the bottom end of the guide rod is provided with two groups of lower heads each comprising a straight blade head and a lower oblique blade head, the straight blade heads and the lower oblique blade heads are uniformly distributed in a circumferential interval staggered manner; the straight blade head is located between the upper oblique blade head and the lower oblique blade head in the axial direction of the tool, the main cutting edges of the upper oblique blade head and the lower oblique blade head are arranged in an upper-lower opposite manner, and the main cutting edges and the tool axis have an included angle; the lower oblique blade head in the same group of lower heads is located upstream of the straight blade head in the rotating direction of the tool, and the positions of the two upper oblique blade heads and the two lower oblique blade heads are consistent. The tool can realize no burr, tearing and other damages in one-time milling.

Description

Technical Field

[0001] This invention relates to cutting tools for burr suppression during machining of carbon fiber reinforced composite materials, and particularly to milling tools for burr suppression during side milling of carbon fiber reinforced composite materials. Background Technology

[0002] With the increasingly widespread application of carbon fiber reinforced composite materials in aerospace, automotive, and other fields, the demand for high-efficiency, low-damage processing is also constantly growing. In the milling of carbon fiber reinforced composite material sheets, the carbon fibers are difficult to cut due to the semi-constrained state near the upper and lower surfaces, easily generating burrs. Unlike burrs produced by metal milling, burrs in carbon fiber composite materials can also easily cause tearing, requiring a specific deburring process. Therefore, achieving burr-free milling is of great significance for the high-efficiency, low-damage processing of carbon fiber composite materials.

[0003] To address the aforementioned issues, researchers both domestically and internationally have conducted relevant studies. For example, patent document CN114535676A, published on May 27, 2022, discloses a machining tool capable of suppressing burrs. It includes a cutting section and a shank connected together. The free end of the cutting section is designated as the bottom end, and the free end of the shank as the top end. A first cutting edge and a first chip removal groove matching the first cutting edge are spirally arranged from the bottom end to the top end. A second cutting edge is provided between the first cutting edge and the shank. The first chip removal groove extends towards the shank to form a second chip removal groove matching the second cutting edge. The angle between the second cutting edge and the central axis of the shank is -10° to 5°. The spiral structure of the first cutting edge provides radial force to achieve cutting, while the second cutting edge performs horizontal cutting to prevent burrs from escaping being cut, thus suppressing burr formation. This technical solution proposes suppressing burrs by using a structure where different parts of the end mill have different helix angles. However, it only prevents burrs from escaping using a small helix angle cutting edge and does not improve the semi-constrained state of the upper and lower surface materials. For example, patent document CN106312156A, published on January 11, 2017, discloses a method for obtaining the cutting angle to suppress milling burrs in carbon fiber laminates. This method mainly involves constructing a calculation model of the milling burr angle and cutting force angle in carbon fiber laminates, obtaining the cutting angle where the cutting force is parallel to the carbon fiber layer, and then designing orthogonal experiments to compare burr defects under specified process conditions to select the effective cutting angle for suppressing milling burrs in carbon fiber laminates. This technical solution uses a side-tilt milling method to suppress burr generation, but the presence of the side-tilt angle results in a large inclined surface on the workpiece. Eliminating the machining inclination angle requires adding a process step, reducing machining efficiency, and the introduction of the new process may also generate burrs. Therefore, there is still a lack of cutting tools for high-efficiency milling of carbon fiber reinforced composite materials with few or no burrs. Summary of the Invention

[0004] In view of the above-mentioned prior art, the present invention aims to solve the problem that existing milling tools for carbon fiber composite materials are prone to burrs, tears and other damage, which seriously affect processing efficiency and processing quality. The invention provides a milling tool that can suppress burrs in carbon fiber reinforced composite materials and can achieve burr-free, tear-free and other damage-free milling in one pass.

[0005] To address the aforementioned technical problems, this invention proposes a milling cutter capable of suppressing burrs on carbon fiber reinforced composite materials. The cutter comprises an upper cutting edge and a lower cutting edge. The upper cutting edge includes a body, with a first cutter head mounting seat at its bottom. Two circumferentially distributed upper beveled cutter heads are mounted on the first cutter head mounting seat. A central axial hole is provided within the body, extending from the bottom of the first cutter head mounting seat to the upper-middle portion of the body. The lower cutting edge includes a guide rod that passes through the central axial hole, is fixed to the body of the upper cutting edge, and its axial position can be adjusted. A second cutter head mounting seat is located at the bottom of the guide rod, with two sets of lower cutter heads mounted on the second cutter head mounting seat. Each set of lower cutter heads includes one straight-edged cutter head and one lower beveled cutter head. The two straight-edged cutter heads and two lower beveled cutter heads in the two sets of lower cutter heads are evenly distributed circumferentially at alternating intervals.

[0006] In the axial direction of the milling cutter, the straight-edged cutter head is located between the upper-heeled cutter head and the lower-heeled cutter head. The main cutting edges of the upper-heeled cutter head and the lower-heeled cutter head are arranged vertically opposite each other, and the angle between the main cutting edges and the tool axis is θ, where θ = 45°~60°. In the rotation direction of the milling cutter, in the same group of lower cutter heads, the lower-heeled cutter head is located upstream of the straight-edged cutter head, and the two upper-heeled cutter heads are in the same position as the two lower-heeled cutter heads.

[0007] Furthermore, in the milling tool described in this invention, wherein:

[0008] On the outer surface of the body, above the central axial hole, there is a plane parallel to the axis. Two first threaded holes, radially communicating with the central axial hole, are provided on this plane. On the body, above the first cutter head mounting seat, there are two circumferentially distributed guide grooves and two circumferentially distributed rectangular grooves. The straight-edged cutter head is embedded in the guide grooves. The bottom of each rectangular groove has a second threaded hole radially communicating with the central axial hole. Fastening bolts are provided in both the first and second threaded holes, and these bolts are tightened against the guide rod, thereby fixing the lower and upper cutting edges. Simultaneously, the axial position of the lower cutting edge can be adjusted.

[0009] The front surfaces of the upper and lower oblique cutting edges are arc-shaped.

[0010] The guide rod is provided with scales along the axial direction, which are used to adjust and determine the axial position of the lower cutting edge part.

[0011] The radius from the lower cutting tip of the upper oblique blade bit to the axis of the guide rod is R1, the radius from the upper cutting tip of the lower oblique blade bit to the axis of the guide rod is R1, the radius from the main cutting edge of the straight blade bit to the axis of the guide rod is R2, R1-R2=t, and t=0.1~0.7mm; the length of the straight blade bit is L, and L=10-30mm.

[0012] The upper cutting edge part is equipped with a variety of upper oblique blade bits with different R2 values, and the lower cutting edge part is equipped with a variety of straight blade bits with different R2 values and a variety of lower oblique blade bits with different R1 values; in the same milling process, the R1 values of the upper oblique blade bit and the lower oblique blade bit are the same.

[0013] The upper oblique blade bit is mounted on the first bit mounting seat by a mechanical clamping method; both the lower oblique blade bit and the straight blade bit are respectively mounted on the second bit mounting seat by a mechanical clamping method.

[0014] The radius from the lower cutting tip of the upper oblique blade bit to the axis of the guide rod is R1, the radius from the upper cutting tip of the lower oblique blade bit to the axis of the guide rod is R1, the distance between the outer cutting tips of the upper oblique blade bit and the lower oblique blade bit is H, the thickness of the workpiece to be machined is T, and T<H≤T+(R2-R1)·ctgθ; by adjusting the axial position of the lower cutting edge part, burr-free edge milling of plate parts with different thicknesses is realized.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0016] Since the milling cutter of the present invention is designed with straight blades and oblique blades, when the cutter is used for edge milling of thin plate parts such as composite materials, the straight blades and the oblique blades perform cutting alternately, and two methods can be adopted for milling. The first method is: first use the straight blade to cut the material to be removed, at this time, burrs will appear on the upper and lower edges, and then use the oblique blade to perform chamfering within the range of the upper and lower edges to remove the burrs. The second method is: first use the oblique blade to complete the chamfering of the area to be cut, and then use the straight blade to remove the remaining material to be removed. Since the chamfer width of the edge is slightly larger than the milling width, no burrs will be generated while ensuring the chamfered surface. The straight blade of the cutter of the present invention can remove most of the material to be removed, and the oblique blade can remove the burrs on the edge, which can meet the burr-free edge milling requirements of thin-walled and thin-plate parts in one process. In addition, the distance between the two oblique blades can be adjusted according to the different thicknesses of the workpiece, so that the cutter has the function of one cutter for multiple uses. Brief Description of the Drawings

[0017] Figure 1 is a schematic diagram of the overall structure of the milling cutter of the present invention;

[0018] Figure 2 yes Figure 1 A three-dimensional structural diagram of the upper cutting edge of the knife shown in the figure;

[0019] Figure 3 yes Figure 2 A three-dimensional structural diagram of the upper blade from another perspective;

[0020] Figure 4 yes Figure 2 The front view of the upper blade shown;

[0021] Figure 5 yes Figure 4 The side view of the upper blade shown;

[0022] Figure 6 yes Figure 1 A schematic diagram of the structure of the lower blade shown in the figure;

[0023] Figure 7 yes Figure 6 Enlarged cross-sectional view of the lower blade shown;

[0024] Figure 8 This is a schematic diagram of two cutting states that exist when a milling cutter uses its beveled edge to remove burrs from the upper and lower edges of a workpiece.

[0025] Figure 9 This is a schematic diagram of two cutting states when a milling cutter is cutting with its straight cutting edge.

[0026] In the picture:

[0027] 1-Upper cutting edge 11-Upper oblique cutting head 12-Guide groove

[0028] 13-First threaded hole; 14-Fasting bolt; 15-Central axial hole

[0029] 16-First cutter head mounting base 2-Lower cutting edge 21-Lower oblique cutting edge

[0030] 22-Straight blade tip 23-Guide rod 24-Rectangular groove

[0031] 25-Second threaded hole; 26-Second cutter head mounting seat Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention.

[0033] This invention proposes a milling tool for suppressing burrs in carbon fiber reinforced composite materials, comprising an upper cutting edge 1 and a lower cutting edge 2. For example... Figure 1 and Figure 2As shown, the upper cutting edge 1 includes a body, and a first cutting head mounting seat 16 is provided at the bottom end of the body. Two circumferentially distributed upper oblique cutting heads 11 are mounted on the first cutting head mounting seat 16. A central axial hole 15 is provided in the body from the bottom of the first cutting head mounting seat 16 to the upper middle part of the body. A plane parallel to the axis is provided on the outer surface of the body above the central axial hole 15. Two first threaded holes 13 are provided on the plane that radially penetrate the central axial hole 15.

[0034] like Figure 6 and Figure 7 As shown, the lower cutting edge 2 includes a guide rod 23, which is inserted into the central axial hole 15, fixed to the body of the upper cutting edge 1, and whose axial position can be adjusted; the bottom end of the guide rod 23 is provided with a second cutter head mounting seat 26, on which two sets of lower cutter heads are mounted, each set of lower cutter heads including a straight-edged cutter head 22 and a lower oblique-edged cutter head 21; the two straight-edged cutter heads 22 and the two lower oblique-edged cutter heads 21 in the two sets of lower cutter heads are evenly distributed in a staggered manner along the circumferential direction.

[0035] like Figures 1 to 5 The main body is provided with two circumferentially distributed guide grooves 12 and two circumferentially distributed rectangular grooves 24 located above the first cutter head mounting seat 16; the straight-bladed cutter head 22 is embedded in the guide groove 12, and the bottom of the rectangular groove 24 is provided with a second threaded hole 25 that radially communicates with the central axial hole 15.

[0036] After inserting the guide rod 23 into the central axial hole 15, fastening bolts 14 are screwed into the two first threaded holes 13 respectively. The fastening bolts 14 are tightened onto the guide rod 23. A fastening bolt is screwed into the second threaded hole 25, which is tightened onto the straight cutting head, thereby fixing the lower cutting edge 2 and the upper cutting edge 1. Since the guide rod 23 can be adjusted according to the thickness of the workpiece during installation, the position of the lower cutting edge 2 can be easily determined.

[0037] In the axial direction of the milling cutter, the straight cutting head 22 is located between the upper oblique cutting head 11 and the lower oblique cutting head 21. The main cutting edges of the upper oblique cutting head 11 and the lower oblique cutting head 21 are arranged opposite each other, and the included angle between the main cutting edge and the tool axis is θ, where θ = 45°~60°.

[0038] In the rotation direction of the milling cutter, in the same group of lower cutter heads, the lower helical cutter head 21 is located upstream of the straight cutter head 22, and the two upper helical cutter heads 11 are in the same position as the two lower helical cutter heads 21.

[0039] like Figure 6as shown, the guide rod 23 is provided with scales along the axial direction, for adjusting and determining the axial position of the lower cutting portion 2. As Figure 7 as shown, the rake faces of the upper oblique cutting tip 11 and the lower oblique cutting tip 21 are arc-shaped surfaces.

[0040] As Figure 8 and Figure 9 as shown, the radius from the lower side tool tip of the upper oblique cutting tip 11 to the axis of the guide rod 23 is R1, the radius from the upper side tool tip of the lower oblique cutting tip 21 to the axis of the guide rod 23 is R1, the radius from the main cutting edge of the straight cutting tip 22 to the axis of the guide rod 23 is R2, R1-R2=t, t=0.1~0.7mm; the length of the straight cutting tip 22 is L, L=10-30mm. The distance between the outer tool tips of the upper oblique cutting tip 11 and the lower oblique cutting tip 21 is H, the thickness of the workpiece to be machined is T, T<H≤T+(R2-R1)·ctgθ; by adjusting the axial position of the lower cutting portion 2, burr-free edge milling of plate parts with different thicknesses is achieved.

[0041] In the present invention, the upper cutting portion 1 may be equipped with a plurality of upper oblique cutting tips 11 having different R2 values, and the lower cutting portion 2 is equipped with a plurality of straight cutting tips 22 having different R2 values and a plurality of lower oblique cutting tips 21 having different R1 values; during the same milling process, the R1 values of the upper oblique cutting tip 11 and the lower oblique cutting tip 21 are the same.

[0042] In the present invention, the upper oblique cutting tip 11 is mounted on the first tip mounting seat 16 in a mechanically clamped manner; both the lower oblique cutting tip 21 and the straight cutting tip 22 are respectively mounted on the second tip mounting seat 26 in a mechanically clamped manner.

[0043] Example: Taking the burr-free milling of the side surfaces of thin-walled and thin-plate parts made of carbon fiber reinforced composite material as an example,

[0044] As Figure 8 and 9As shown, the diameter of the circle where the outer tool tip of the lower oblique blade bit 21 is located is R1, the diameter of the circle where the cutting edge of the straight blade bit 22 is located is R2, the length of the straight blade is L, the straight blade bit 22 of the lower blade part 2 is inserted into the guide groove 12 of the upper blade part 1 under the guiding action of the guide rod 23, and the surface of the guide rod 23 is provided with scales; the included angle between the upper oblique blade bit 11 and the tool axis and the included angle between the lower oblique blade bit 21 and the tool axis are both θ, the directions of the upper oblique blade bit 11 and the lower oblique blade bit 21 are opposite and symmetrical, and the length L of the straight blade bit is 20 mm; the two lower oblique blade bits 21 and the two straight blade bits 22 are evenly distributed in a staggered manner along the circumferential direction. The upper oblique blade bit 11 in the upper blade part 1 is mounted on the main body of the upper blade part 1 in a clamped manner. Similarly, the lower oblique blade bit 21 and the straight blade bit 22 in the lower blade part 2 are also mounted on the main body of the lower blade part 2 in a clamped manner. In this embodiment, θ=60°. There is the following relationship between R1, the diameter of the circle where the outer tool tip of the lower oblique blade bit 21 is located, and R2, the diameter of the circle where the cutting edge of the straight blade bit 22 is located: R1-R2=0.2 mm; the distance between the outer tool tips of the upper oblique blade bit 11 and the lower oblique blade bit 21 is H, and there is the following relationship between H and the thickness T of the machined workpiece: T<H≤T+(R2-R1)·ctgθ. By changing the relative axial positions of the upper blade part 1 and the lower blade part 2, burr-free milling of plates with different thicknesses is realized.

[0045] In this embodiment, the oblique blade of the upper blade part 1 and the oblique blade and straight blade of the lower blade part 2 are all symmetrically arranged in the three-dimensional space, so that while completing the side material removal of thin-walled and thin-plate parts, the axial force of the milling cutter on the workpiece during the milling process can also be counteracted, thereby reducing the generation of burrs. When the milling cutter of the present invention machines the side surfaces of thin-walled and thin-plate parts made of carbon fiber reinforced composite materials, the straight blades and the oblique blades perform cutting in a staggered manner. There are two situations: the first one is as shown in Figure 9 Situation 1a shown on the right, the straight blade bit 22 first cuts the material to be removed, and at this time, burrs will appear on the upper and lower edges of the workpiece; the next step is as shown in Figure 8 Situation 1b shown on the right, the upper and lower oblique blade bits 11 and 21 perform chamfering on a tiny range of the upper and lower edges of the workpiece to remove burrs. The second situation is as shown in Figure 8 Situation 2a shown on the left, the upper and lower oblique blade bits 11 and 21 first complete the chamfering of the cutting zone, and the next step is as shown in Figure 9In scenario 2b shown on the left, the straight-edged cutter head 22 removes the remaining material. Since the chamfer width is slightly larger than the milling width, no burrs or large chamfer surfaces are generated. Therefore, the beveled cutter heads of the upper cutting edge 1 and lower cutting edge 2 of the tool of this invention complete the minor removal of the upper and lower edges of the side surface during burr-free milling of thin-walled and thin-plate parts made of carbon fiber reinforced composite materials. The straight-edged cutter head 22 of the lower cutting edge 2 completes the removal of the remaining material. This one-time processing can meet the burr-free milling requirements of thin-walled and thin-plate parts in a single operation, improving milling efficiency. This invention allows the distance between the beveled cutters to be adjusted according to the thickness of the workpiece, providing a multi-purpose function.

[0046] Although the present invention has been described above in conjunction with the accompanying drawings, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many modifications under the guidance of the present invention without departing from the spirit of the present invention, and these modifications are all within the protection scope of the present invention.

Claims

1. A milling cutter for suppressing burrs on carbon fiber reinforced composite materials, comprising an upper cutting edge (1) and a lower cutting edge (2). The upper blade (1) includes a body, and a first blade mounting seat (16) is provided at the bottom end of the body. Two circumferentially distributed upper oblique blades (11) are mounted on the first blade mounting seat (16). A central axial hole (15) is provided in the body from the bottom of the first blade mounting seat (16) to the upper middle part of the body. The lower cutting edge (2) includes a guide rod (23), which is inserted into the central axial hole (15), fixed to the body of the upper cutting edge (1), and can be adjusted in axial position; the bottom end of the guide rod (23) is provided with a second cutter head mounting seat (26), and two sets of lower cutter heads are mounted on the second cutter head mounting seat (26). Each set of lower cutter heads includes a straight-edged cutter head (22) and a lower oblique-edged cutter head (21); the two straight-edged cutter heads (22) and the two lower oblique-edged cutter heads (21) in the two sets of lower cutter heads are evenly distributed in a staggered manner along the circumferential direction; In the axial direction of the milling cutter, the straight cutting head (22) is located between the upper oblique cutting head (11) and the lower oblique cutting head (21). The main cutting edges of the upper oblique cutting head (11) and the lower oblique cutting head (21) are arranged opposite each other, and the included angle between the main cutting edge and the tool axis is θ, where θ = 45°~60°. In the rotation direction of the milling cutter, in the same set of lower cutter heads, the lower helical cutter head (21) is located upstream of the straight cutter head (22), and the two upper helical cutter heads (11) are in the same position as the two lower helical cutter heads (21).

2. The milling tool according to claim 1, characterized in that, On the outer surface of the body, above the central axial hole (15), there is a plane parallel to the axis. On the plane, there are two first threaded holes (13) that are radially connected to the central axial hole (15). On the body, above the first cutter head mounting seat (16), there are two guide grooves (12) and two rectangular grooves (24) that are evenly distributed in the circumferential direction. The straight-edged cutter head (22) is embedded in the guide groove (12). The bottom of the rectangular groove (24) is provided with a second threaded hole (25) that is radially connected to the central axial hole (15). Fastening bolts are provided in the first threaded hole (13) and the second threaded hole (25). The fastening bolts are all pressed against the guide rod (23), thereby fixing the lower cutting edge (2) and the upper cutting edge (1). At the same time, the axial position of the lower cutting edge (2) can be adjusted.

3. The milling tool according to claim 1, characterized in that, The front surfaces of the upper oblique blade (11) and the lower oblique blade (21) are arc-shaped.

4. The milling tool according to claim 1, characterized in that, The guide rod (23) has a scale along the axial direction for adjusting and determining the axial position of the lower blade (2).

5. The milling tool according to claim 1, characterized in that, The radius from the lower side tool tip of the upper oblique edge tool bit (11) to the axis of the guide rod (23) is R1, the radius from the upper side tool tip of the lower oblique edge tool bit (21) to the axis of the guide rod (23) is R1, the radius from the main cutting edge of the straight edge tool bit (22) to the axis of the guide rod (23) is R2, R1-R2=t, and t=0.1~0.7mm; the length of the straight edge tool bit (22) is L, and L=10-30mm.

6. The milling tool according to claim 1, characterized in that, The upper edge portion (1) is equipped with a variety of upper oblique edge tool bits (11) with different R2 values, and the lower edge portion (2) is equipped with a variety of straight edge tool bits (22) with different R2 values and a variety of lower oblique edge tool bits (21) with different R1 values; during the same milling process, the R1 values of the upper oblique edge tool bit (11) and the lower oblique edge tool bit (21) are the same.

7. The milling tool according to claim 1, characterized in that, The upper oblique edge tool bit (11) is mounted on the first tool bit mounting seat (16) in a clamped manner; both the lower oblique edge tool bit (21) and the straight edge tool bit (22) are respectively mounted on the second tool bit mounting seat (26) in a clamped manner.

8. The milling tool according to claim 1, characterized in that, The radius from the lower side tool tip of the upper oblique edge tool bit (11) to the axis of the guide rod (23) is R1, the radius from the upper side tool tip of the lower oblique edge tool bit (21) to the axis of the guide rod (23) is R1, the distance between the outer side tool tips of the upper oblique edge tool bit (11) and the lower oblique edge tool bit (21) is H, the thickness of the workpiece to be machined is T, and T<H≤T+(R2-R1)·ctgθ; by adjusting the axial position of the lower edge portion (2), burr-free edge milling of plate parts with different thicknesses is realized.

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