CN105034076B - A kind of dedicated tool of the efficient drilling of fibre reinforced composites - Google Patents

Abstract

The invention relates to a special tool for high-efficiency hole-making of fiber-reinforced composite materials, belonging to the technical field of drilling tools in mechanical processing, and relates to a special tool for high-efficiency hole-making of fiber composite materials. The special tool has a micro-tooth structure with cross rotation and a multi-edge double-vertex angle with a vibration-suppressing structure. This tool is divided into the first main cutting area formed by the first main cutting edge envelope, the second main cutting edge envelope Six areas are formed: the second main cutting zone, the secondary cutting zone whose envelope is the left-handed helix angle of the final hole size, the variable diameter zone, the clamping zone and the micro-tooth cutting zone. The invention adopts a multi-blade double-vertex structure to realize the integrated processing of drilling, expansion and reaming, reduce the axial force of drilling, and reduce delamination defects. Through the micro-tooth structure with cross-rotation on adjacent cutting edges, the exit and entrance burrs can be effectively removed, the tear damage when forming the final hole is reduced, the quality of the entrance hole wall is improved, and the one-time use of fiber reinforced composite materials is finally realized. Low damage hole making.

Description

A special tool for high-efficiency hole-making of fiber-reinforced composite materials

technical field

The invention belongs to the technical field of drilling tools in mechanical processing, and relates to a special tool for high-efficiency hole making of fiber reinforced composite materials. It is suitable for one-time high-quality and high-efficiency hole-making processing of carbon fiber reinforced composite materials.

Background technique

Fiber-reinforced composite materials generally have excellent mechanical properties. Its overall performance can be designed, and it is easy to manufacture the overall shape synchronously. It is widely used in components in aerospace and other fields, which can reduce structural weight, reduce manufacturing cycle, and improve reliability. sex. In particular, carbon fiber reinforced composite materials, with their high specific strength and high specific stiffness, are often used to manufacture core load-bearing components of aircraft. However, in order to realize the connection and assembly of parts, such materials must be machined accordingly. Among them Machining connection holes is one of the most arduous tasks in machining, for example, a Boeing 747 aircraft has more than three million connection holes. However, since carbon fiber reinforced composite materials are mainly composed of carbon fiber reinforced phases and resin matrix phases in a mixed form, they exhibit obvious anisotropy and lamination characteristics macroscopically, and their interlayer bonding strength is much lower than that in other directions. Due to the weak constraints of the entrance and exit positions during drilling, the drill tip is likely to generate a large axial force, which pushes away the outermost layers of material, resulting in delamination damage, and the fiber cannot be cut to cause the fiber to bend and cause tearing and burrs and other damage. At the same time, because the carbon fiber reinforced phase is extremely hard, it is easy to aggravate the wear of the tool, resulting in an unsharp cutting edge, making it difficult to cut the fiber, and easily causing serious exit and entrance burrs. In order to overcome the above problems and achieve high-quality hole processing on carbon fiber reinforced composite materials, companies generally use expensive diamond-coated tools and adopt multiple processes of "drilling-reaming-rough reaming-fine reaming" to ensure The quality of the hole.

Research at home and abroad has shown that the geometric structure of the tool is an important factor affecting the quality of hole-making of fiber-reinforced composite materials. Therefore, a variety of hole-making tools for carbon fiber-reinforced composite materials with different structural geometric forms have been developed at home and abroad. These tools have their own advantages and disadvantages. . Sandvik Intellectual Property Co., Ltd. discloses a "twist drill for advanced materials", patent application number 201180020931.2, which relates to a twist drill for drilling holes such as carbon fiber reinforced composite materials and glass fiber reinforced composite materials, proposed Having a variable helix with defined start and end helix angles to combine with the primary and secondary relief angles makes the twist drill suitable for thrust minimization. Compared with the twist drill, this kind of drill can reduce the delamination defect to a certain extent, but the burr defect will appear quickly with the wear of the tool, and the service life of the drill is shorter. Jia Zhenyuan of Dalian University of Technology and others disclosed "a high-efficiency special drill bit for carbon fiber composite material hole making", patent application number 201510408743.7, which relates to the double vertices with toothed micro-edges for carbon fiber composite material hole making Structural drill, through the double-vertex structure of the main cutting edge and the micro-tooth structure at the connecting part of the main cutting edge and the auxiliary cutting edge, realizes the function of drilling-expanding-reaming integrated processing, and obtains holes with high dimensional accuracy. However, since the micro-tooth structure is at the cutting edge of the final cutting and forming, it is easy to cause tiny tear damage at the exit and entrance, and reduce the smoothness of the inner wall. Vibration occurs in the middle, causing the outer fiber at the entrance to bulge, and the hole wall is severely scratched.

Contents of the invention

The technical problem to be solved by the present invention is to overcome the problems that carbon fiber composite materials are easy to be exported during hole making, and are prone to damage such as delamination, burrs, tears, etc., and the problem of poor hole wall quality, and to invent a special tool for efficient hole making of fiber reinforced composite materials , especially suitable for hole-making processing of high-performance carbon fiber composite materials. The tool is a multi-blade double-vertex angle drill with a micro-tooth structure with cross-handed directions. The micro-tooth structure, the transition position between the second main cutting edge and the auxiliary cutting edge is designed as a circular arc transition, and the tail end of the auxiliary cutting edge is designed as a variable diameter structure, which can realize one-time low-damage hole making and improve the use of the drill bit. Longer life, lower usage cost.

The technical solution adopted in the present invention is a special tool for high-efficiency hole making of fiber-reinforced composite materials. The first major cutting zone A formed by the envelope of the first major cutting edge 1, the second major cutting zone B formed by the envelope of the second major cutting edge 2, and the secondary cutting with the envelope of the left-handed helix of the final hole size Area C, variable diameter area D, clamping area E, and micro-tooth cutting area G; among them, the first main cutting area A has two first main cutting edges 1, and the apex angle α formed by them is an obtuse angle; The second main cutting area B has four second main cutting edges 2, and the apex angle β formed by it is an acute angle, and the first and second main cutting edges form a multi-edge double-vertex structure; Smaller left-handed helix angle; in the transition zone F in the rear part of the second main cutting zone B, the rear section of the second main cutting edge 2 is connected with the secondary cutting edge 3 by an arc curve; the diameter reduction zone D is in the secondary cutting zone C The tail end is designed as a variable diameter structure, the axial length of the variable diameter area D is 1/2 of the axial length of the auxiliary cutting area C, the diameter of the variable diameter area D is D ₂ ; the diameter of the auxiliary cutting edge 3 is D ₁ , Its end 4 does not exceed the diameter reducing area D;

The four second main cutting edges 2 of the second main cutting zone B are distributed with a micro-tooth cutting zone G, and the micro-tooth cutting zone G is composed of several micro-tooths 5; the micro-tooth 5 is on the same second main cutting edge 2 The contour structure is the same; there are 3-5 micro-teeth 5 distributed along each second main cutting edge 2, and the distribution number on each second main cutting edge 2 is the same, and the axial position is the same; The helical angle of the microtooth axial line 7 of the microtooth 5 on the cutting edge 2 is different from that of the tool axial line 6, and the helical angle of the microtooth 5 on the two opposite second main cutting edges 2 is the same; Wherein, the heeding angle of the micro-tooth 5 on a pair of second main cutting edges 2 is a right-handed angle γ _R is an obtuse angle, and the helical angle of the micro-tooth 5 on another pair of second main cutting edges 2 is a left-handed The angle _{γ L} is an acute angle; they together form the micro-tooth structure with cross-handed directions on adjacent cutting edges; the projected profile of the micro-tooth 5 is elliptical or circular; The upper right inclination δ _R of the two main cutting edges (2) and the lower right inclination ε _R of the lower tooth edge and the second main cutting edge (2 ₎ are obtuse angles; The left upper inclination δ _L of the main cutting edge (2) and the left lower inclination ε _L of the lower tooth edge and the second main cutting edge (2) are acute angles; among the micro teeth 5, the micro teeth farthest from the drill point are located in the second main cutting Below the transition zone F in zone B, the distance between the microteeth 5 distributed on the same second main cutting edge 2 is not less than 1.5 mm, and the tooth width is 0.8-1.5 times the tooth pitch.

The effect and benefit of the present invention is a special tool for high-efficiency hole-making of fiber reinforced composite materials, which adopts a double-vertex structure to realize integrated processing of drilling, expanding and reaming, reduce the axial force of drilling, and reduce delamination defects. . Through the micro-tooth structure with cross-rotation on adjacent cutting edges, the burrs generated during the hole making process can rebound into the micro-tooth structure and be cut by the micro-tooth, which can effectively remove the exit and entry burrs, and reduce the time for forming the final hole. tearing damage; the transition position between the second main cutting edge and the auxiliary cutting edge is designed as a circular arc transition, which can effectively reduce the vibration of the auxiliary cutting edge cutting in, and through the variable diameter structure at the end of the auxiliary cutting edge, the drilling to the end can be effectively controlled. The vibration of the end improves the quality of the entrance hole wall; and finally realizes the one-time low-damage hole making of fiber reinforced composite materials.

Description of drawings

Fig. 1 is a front view of a special tool for high-efficiency hole making of fiber-reinforced composite materials, Fig. 2(a) is a partial enlarged view of a right-handed micro-tooth, and Fig. 2(b) is a view of Fig. 2(a) along the micro-tooth axis Line direction oblique view, Figure 3(a) is a partially enlarged view of a left-handed micro-tooth, Figure 3(b) is an oblique view of Figure 3(a) along the line direction of the micro-tooth axis, Figure 4(a) is a left-handed micro-tooth The schematic diagram of the upper tooth edge cutting the entrance burr; Fig. 4(b) is the schematic diagram of the lower tooth edge of the right-handed microtooth cutting the exit burr. Among them, A-the first main cutting zone, B-the second main cutting zone, C-sub-cutting zone, D-diameter reducing zone, E-clamping zone, F-transition zone, G-micro-tooth cutting zone, 1- The first main cutting edge, 2-the second main cutting edge, 3-the secondary cutting edge, 4-the end of the secondary cutting edge, 5-micro-tooth, 6-tool axial line, 7-micro-tooth axial line, 8-burr , 9-workpiece entrance side, 10-workpiece exit side, α-first vertex angle, β-second vertex angle, γ _R -micro-tooth right-handed angle, γ _L -micro-tooth left-handed angle, δ _R -upper right Inclination angle, δ _L - up-left inclination, ε _R - down-right inclination, ε _L - down-left inclination, D ₁ - shaft diameter of secondary cutting area C, D ₂ - shaft diameter of reducing area D.

detailed description

The specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings and technical solutions. A fiber-reinforced composite material high-efficiency hole-making tool, the specific embodiment of the tool is shown in Figure 1, the tool is divided into a first main cutting zone A formed by the envelope of the first main cutting edge 1, a second main cutting edge 2 The second main cutting zone B formed by the envelope, the secondary cutting zone C with the left-handed helix angle whose envelope is the size of the final hole, the variable diameter zone D, the clamping zone E and the micro-tooth cutting zone G six areas. Among them, the first main cutting area A has two first main cutting edges 1, and the apex angle α formed by them is an obtuse angle, so that the first main cutting edge 1 has high rigidity and can better center after drilling. function, to ensure the smooth progress of the drilling subsequent drilling process, this embodiment adopts α=118°; the second main cutting zone B has 4 second main cutting edges 2, and the vertex angle β formed by it is an acute angle, so that the second The main cutting edge 2 is sharp, the axial component force is small, and it is not easy to cause delamination damage. The small left-handed helix angle of the secondary cutting edge 3 is beneficial to reduce the axial force and realize reaming with a large rake angle.

As shown in FIG. 1 , microtooth cutting zones G are distributed on the four second main cutting edges 2 of the second main cutting zone A; the microtooth cutting zone G is composed of several microtooths 5 . As shown in Figure 2a) and Figure 3a), the micro-tooth 5 has the same profile structure on the same second main cutting edge 2; three micro-tooth 5 are distributed along the direction of each second main cutting edge 2, and on each second main cutting edge 2 The number of distributions on the two major cutting edges 2 is the same and the axial positions are the same. The micro-tooth axial line 7 of the micro-tooth 5 on the adjacent second main cutting edge 2 is different from the tool axial line 6. In the cutting area G of the two symmetrical second main cutting edges 2 The helical angles of the microtooth 5 inside are the same; the right-handed angle γ _R of the microtooth 5 on one pair of second main cutting edges 2 is an obtuse angle of 120°, which is right-handed, and the other pair of second main cutting edges The left-handed angle γ _L of the micro-tooth 5 on the cutting edge 2 is an acute angle of 70°, which is left-handed; the projected profile of the micro-tooth 5 is elliptical; the right-handed angle γ _R of the micro-tooth is an obtuse angle on the upper tooth edge The inclination angle δ _R with the second main cutting edge 2 is 120°, the _inclination angle ε _R between the lower tooth edge and the second main cutting edge 2 is 130°; The inclination angle δ _L of the cutting edge 2 is 75°, and the inclination angle ε _L between the lower tooth edge and the second main cutting edge 2 is an acute angle of 85°, see Fig. 2b) and Fig. 3b).

During the drilling process, when the micro-tooth at the second main cutting edge cuts into the material, the burrs 8 at the exit and entrance will spring back into the micro-tooth 5, because the rotation speed in drilling is much higher than the feed speed, as shown in Figure 4a ), 4b); at the entrance, the upper tooth edge of the left-handed micro-tooth 5 moves relative to the workpiece inlet side 9, forming a scissors structure, and cuts off the burr 8; when exiting; the lower tooth edge of the right-handed micro-tooth 5 is relative to the workpiece exit The side 10 moves to form a scissors structure to cut off the burrs 8 . The micro-teeth 5 of different rotation directions are arranged along the cutting edge in the same way, which can ensure the effective shear removal of the exit and entrance burrs in stages during the cutting process; the micro-teeth 5 distributed on the same second main cutting edge 2 The distance between them is 1.5mm, and the tooth width is 1.5 times the tooth pitch. During the drilling process, the rigidity of the micro-tooth can be better guaranteed to avoid damage to the micro-tooth.

As shown in Figure 1, the transition zone F between the second main cutting zone B and the secondary cutting zone C is a circular arc, and the circular arc edge formed can effectively reduce the severe vibration of the secondary cutting edge 3 in the initial stage of cutting, and give the hole at the entrance of the hole The wall is scratched. At the same time, the axial length of the auxiliary cutting zone C is 20mm, the diameter D ₁ =8mm, the axial length of the variable diameter zone D is 10mm, and the diameter becomes smaller to D ₂ =7.2mm, which can ensure that when the tool is machining a thicker hole , will not reduce the quality of the hole wall at the entrance of the hole due to the friction between the longer secondary cutting edge 3 and the hole wall, or even vibration.

A high-efficiency hole-making tool for fiber-reinforced composite materials of the present invention is specially designed for the hole-making process of fiber-reinforced composite materials. The tearing of the entrance; at the same time, it can reduce the vibration of the tool, improve the quality of the hole wall, and form a high-quality final hole at one time.

Claims (1)

1. a dedicated tool for the efficient drilling of fibre reinforced composites, is characterized in that, dedicated tool has micro-toothing of intersection rotation direction and presses down the multiple-cutting-edge Double Tops angle of structure of shaking；This cutter is divided into the first main cutting district (A) of being formed by the first main cutting edge (1) envelope, the second main cutting edge (2) envelope is formed the second main cutting district (B), envelope are the whole secondary cutting region (C) of left-handed Luo Jiao of hole dimension, reducing district (D), clamp area (E) and region, six, micro-tooth cutting region (G)；Wherein, there are 2 the first main cutting edges (1) in the first main cutting district (A), and the drift angle (α) of its formation is obtuse angle；There are 4 the second main cutting edges (2) in second main cutting district (B), and the drift angle (β) of its formation is acute angle, and first, second main cutting edge constitutes multiple-cutting-edge Double Tops corner structure；The front cutting edge (3) of secondary cutting region (C) adopts less left-turn spiral angle；The second main cutting edge (2) back segment in the transition region (F) of the second main cutting district (B) rear section adopts circular curve to be connected with front cutting edge (3)；Reducing district (D) is designed as variable-diameter structure at the tail end of secondary cutting region (C), and the axial length of reducing district (D) is the 1/2 of secondary cutting region (C) axial length, and the diameter of reducing district (D) is (D₂)；The diameter of front cutting edge (3) is (D₁), its end (4) is less than reducing district (D)；

The upper distribution of 4 second main cutting edges (2) in the second main cutting district (B) has micro-tooth cutting region (G), and micro-tooth cutting region (G) is made up of several micro-teeth (5)；Micro-tooth (5) is identical at the upper contour structure of same the second main cutting edge (2)；Micro-tooth (5) has 3-5 along the upper distribution of every second main cutting edge (2), identical at the upper distributed quantity of every second main cutting edge (2), and axial location is identical；Micro-tooth axial line (7) of the micro-tooth (5) on adjacent the second main cutting edge (2) is different from the rotation direction angle that cutter axial line (6) is, identical at the rotation direction angle of micro-tooth (5) of two relative the second main cutting edges (2)；Wherein, the rotation direction angle of the micro-tooth (5) on a pair second main cutting edges (2) is dextrorotation to angle (γ_R) it is obtuse angle, the rotation direction angle of the micro-tooth (5) on the second main cutting edge (2) is left-handed to angle (γ by another_L) it is acute angle；Collectively form and adjacent cutting sword intersects micro-toothing of rotation direction；The projected outline of micro-tooth (5) is oval or circular；Micro-tooth dextrorotation is to angle (γ_R) the upper right inclination angle (δ of upper tooth limit and the second main cutting edge (2)_R) and inclination angle, the bottom right (ε of lower tooth limit and the second main cutting edge (2)_R) for obtuse angle；Micro-tooth is left-handed to angle γ_LInclination angle, upper left (δ for upper tooth limit and second main cutting edge (2) of acute angle_L) and inclination angle, the lower-left (ε of lower tooth limit and the second main cutting edge (2)_L) for acute angle；In micro-tooth (5), micro-tooth of distance apex point farthest is arranged in the second main cutting district (B) transition region (F) below, in micro-tooth (5) of the upper distribution of same the second main cutting edge (2), the distance between each micro-tooth is not less than 1.5mm, and the facewidth is 0.8-1.5 times of space width.