Milling cutter for processing composite material based on liquid nitrogen cooling

Abstract

The utility model discloses a milling cutter for composite material processing based on liquid nitrogen cooling, which comprises a cylindrical cutter handle and a cutting part, the cutting part comprises at least two main cutting edges, at least two auxiliary cutting edges and a chip groove, and liquid nitrogen conveying holes for inputting liquid nitrogen are formed in the center of the cutter handle and the center of the cutting part. The liquid nitrogen conveying hole is a blind hole and provided with a large-diameter section and a small-diameter section, the opening end of the liquid nitrogen conveying hole is arranged at the top end of the large-diameter section and located on the end face of the cutter handle, and the closed end of the liquid nitrogen conveying hole is arranged at the bottom end of the small-diameter section and located in the cutting part. Each liquid nitrogen flow guide groove is communicated with the opening end of the liquid nitrogen conveying hole, a plurality of liquid nitrogen conveying bypass holes which are arranged at intervals are formed in the small-diameter section of the liquid nitrogen conveying hole in the length direction, and the liquid nitrogen conveying bypass holes are communicated with the chip groove. According to the utility model, the phenomena of overheat and shrinkage cavity of the milling cutter during long-time milling can be better prevented.

Description

Technical Field

[0001] The utility model relates to a metal cutting tool for composite material processing, in particular to a milling cutter for composite material processing based on liquid nitrogen cooling, belonging to the technical field of machining tool technology. Background Art

[0002] Composite materials are two-phase or multi-phase structural materials made by mixing a soft and viscous matrix material with a high-strength and high-hardness fiber-reinforced material. Their anisotropy, low thermal conductivity, and low interlayer bonding strength make them typical difficult-to-process materials. For example, carbon fiber reinforced composite materials (CFRP), as an advanced composite material, have excellent comprehensive properties such as high specific strength, high specific stiffness, fatigue resistance, corrosion resistance, and excellent designability. They have been widely used in aerospace, automotive and other fields, such as the Airbus A350XWB. The extensive use of composite materials has greatly reduced the weight of aircraft structures and improved the fuel economy of aircraft. However, in order to achieve the connection and assembly of composite parts, a series of mechanical processing is required.

[0003] Since composite materials show obvious anisotropy and stacking in the macroscopic view, as well as low thermal conductivity and high elasticity, the milling cutter is prone to overheating during processing and shrinkage when milling holes. To this end, technicians opened a through hole that runs through the entire milling cutter in the center of the shank and cutting part of the milling cutter, and injected liquid nitrogen into the through hole to reduce the temperature of the milling cutter during processing and prevent shrinkage. However, in actual use, when the milling cutter is used for a long time, the tool still overheats and shrinkage occurs, and the actual use effect is not ideal. Summary of the invention

[0004] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a milling cutter for composite material processing based on liquid nitrogen cooling and having a simple structure, which can better prevent the overheating and shrinkage of the cutter when the milling cutter is used for a long time.

[0005] In order to solve the above technical problems, the utility model adopts such a milling cutter for composite material processing based on liquid nitrogen cooling, including a cylindrical shank and a cutting part, the cutting part including at least two main cutting edges distributed in a spiral shape on the cylindrical surface of the cutting part, at least two secondary cutting edges distributed on the end surface of the cutting part, and a spiral chip groove distributed between the main cutting edges, a liquid nitrogen delivery hole for inputting liquid nitrogen is opened in the center of the shank and the cutting part, the liquid nitrogen delivery hole is a blind hole and has a large diameter section and a small diameter section, the open end of the liquid nitrogen delivery hole is arranged at the top of the large diameter section and is located on the end surface of the shank, the closed end of the liquid nitrogen delivery hole is arranged at the bottom of the small diameter section and is located in the cutting part, at least three liquid nitrogen guide grooves are opened on the end surface of the shank, each liquid nitrogen guide groove is connected to the open end of the liquid nitrogen delivery hole, a plurality of liquid nitrogen delivery bypass holes arranged at intervals are opened on the small diameter section of the liquid nitrogen delivery hole along the length direction, and the liquid nitrogen delivery bypass holes are connected to the chip groove.

[0006] As a preferred embodiment of the utility model, the liquid nitrogen delivery bypass holes at two adjacent chip removal grooves are arranged alternately along the length direction of the cutting portion.

[0007] As a preferred embodiment of the utility model, a plurality of chip breaking grooves arranged at intervals are provided on the main cutting edge.

[0008] As a preferred embodiment of the present utility model, the at least three liquid nitrogen guide grooves are evenly distributed radially on the end surface of the shank.

[0009] As a preferred embodiment of the present invention, the helix angle of the main cutting edge is 5° to 8°.

[0010] After adopting the above structure, the utility model has the following beneficial effects:

[0011] The liquid nitrogen delivery hole of the utility model is a blind hole and has a large diameter section and a small diameter section. The open end of the liquid nitrogen delivery hole is arranged at the top of the large diameter section and is located on the end face of the tool handle. The closed end of the liquid nitrogen delivery hole is arranged at the bottom of the small diameter section and is located in the cutting part. At least three liquid nitrogen guide grooves are provided on the end face of the tool handle, each of which is connected to the open end of the liquid nitrogen delivery hole. A plurality of liquid nitrogen delivery side holes arranged at intervals are provided on the small diameter section of the liquid nitrogen delivery hole along the length direction, and the liquid nitrogen delivery side holes are connected to the chip removal groove. During operation, when liquid nitrogen enters the open end of the liquid nitrogen delivery hole from the liquid nitrogen guide groove on the end face of the tool handle, the liquid nitrogen cooling is pressurized for the first time. After the liquid nitrogen enters the large diameter section and the small diameter section in turn from the open end of the liquid nitrogen delivery hole, the liquid nitrogen cooling pressure is increased for the second time. When the liquid nitrogen is output from the chip groove through the liquid nitrogen delivery bypass hole, the pressure is higher, thereby effectively reducing the tool overheating, the overtemperature of the processed composite material and the shrinkage cavity phenomenon that occur when the milling cutter is used for a long time. In addition, the higher pressure liquid nitrogen can better prevent dirt on the surface of the composite material and avoid secondary cleaning.

[0012] The liquid nitrogen conveying side holes at two adjacent chip removal grooves of the utility model are arranged in a staggered manner along the length direction of the cutting part. Such a structure can achieve a better cooling effect of the milling cutter and can better reduce the temperature of the processed composite material.

[0013] The utility model has a plurality of chip breaking grooves arranged at intervals on the main cutting edge, and such a structure can further reduce the shrinkage cavity phenomenon caused by the low thermal conductivity of the composite material.

[0014] The main cutting edge helix angle of the utility model is 5° to 8°. The small helix angle can increase the discharge of composite material cutting chips, thereby being more conducive to preventing the tool overheating, the overheating of the processed composite material and the shrinkage phenomenon caused by the long-term use of the milling cutter. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The specific implementation of the utility model is further described in detail below in conjunction with the accompanying drawings.

[0016] Figure 1 The utility model is a structural schematic diagram of a milling cutter for machining composite materials based on liquid nitrogen cooling.

[0017] Figure 2 for Figure 1 Schematic top view of .

[0018] Figure 3 for Figure 1 A three-dimensional schematic diagram of . DETAILED DESCRIPTION

[0019] See also Figures 1 to 3The milling cutter for machining composite materials based on liquid nitrogen cooling shown in the figure comprises a cylindrical tool handle 1 and a cutting part 2, the tool handle 1 and the cutting part 2 are coaxially arranged and made in one piece, the cutting part 2 comprises at least two main cutting edges 2-1 distributed on the cylindrical surface of the cutting part 2 in a spiral shape, at least two secondary cutting edges 2-2 distributed on the end surface of the cutting part 2, and spiral chip grooves 2-3 distributed between the main cutting edges 2. The main cutting edges 2-1 of the utility model preferably have six, i.e., a six-edge milling cutter, corresponding to the six main cutting edges 2-1, and the chip grooves 2-3 also have six and are distributed at intervals, and a liquid nitrogen conveying port for inputting liquid nitrogen is provided in the center of the tool handle 1 and the cutting part 2. Hole 3, the liquid nitrogen delivery hole 3 is a blind hole and has a large diameter section 3-1 and a small diameter section 3-2, the open end 3a of the liquid nitrogen delivery hole 3 is arranged at the top of the large diameter section 3-1 and is located on the end surface of the tool handle 1, the closed end 3b of the liquid nitrogen delivery hole 3 is arranged at the bottom of the small diameter section 3-2 and is located in the cutting part 2, at least three liquid nitrogen guide grooves 1a are opened on the end surface of the tool handle 1, each liquid nitrogen guide groove 1a is connected to the open end 3a of the liquid nitrogen delivery hole 3, and a plurality of liquid nitrogen delivery bypass holes 3c arranged at intervals are opened on the small diameter section 3-2 of the liquid nitrogen delivery hole 3 along the length direction, and the liquid nitrogen delivery bypass hole 3c is connected to the chip removal groove 2-3.

[0020] As a preferred embodiment of the present invention, Figure 1 As shown, the liquid nitrogen delivery bypass holes 3 c at two adjacent chip removal grooves 2 - 3 are arranged alternately along the length direction of the cutting portion 2 .

[0021] As a preferred embodiment of the present invention, Figure 1 , 3 As shown, a plurality of spaced chip breaker grooves 2a are provided on the main cutting edge 2-1. The chip breaker grooves 2a of the utility model are preferably evenly distributed along the length direction of the main cutting edge 2-1. Such a structure can further reduce the shrinkage cavity phenomenon caused by the low thermal conductivity of the composite material.

[0022] As a preferred embodiment of the present invention, Figure 2 As shown, the at least three liquid nitrogen guide grooves 1a are evenly distributed along the radial direction on the end surface of the handle 1. The liquid nitrogen guide grooves 1a of the utility model preferably have six and are evenly distributed along the radial direction on the end surface of the handle 1.

[0023] As a preferred embodiment of the present invention, the helix angle of the main cutting edge 2-1 is 5° to 8°. The optimal helix angle of the main cutting edge 2-1 of the present invention is 5°. The small helix angle can increase the discharge of composite material chips, thereby being more conducive to preventing the milling cutter from overheating during long-term milling, excessive temperature of the processed composite material, and shrinkage.

[0024] After trial, the utility model can better prevent the overheating and shrinkage of the cutter during long-term milling processing, and has achieved good practical effect.

Claims

1. A milling cutter for machining composite materials based on liquid nitrogen cooling, comprising a cylindrical tool holder (1) and a cutting portion (2), the cutting portion (2) comprising at least two main cutting edges (2-1) distributed in a spiral shape on the cylindrical surface of the cutting portion (2), at least two secondary cutting edges (2-2) distributed on the end surface of the cutting portion (2), and a chip groove (2-3) distributed in a spiral shape between the main cutting edges (2-1), a liquid nitrogen delivery hole (3) for inputting liquid nitrogen is opened in the center of the tool holder (1) and the cutting portion (2), characterized in that: The liquid nitrogen delivery hole (3) is a blind hole and has a large diameter section (3-1) and a small diameter section (3-2); the open end (3a) of the liquid nitrogen delivery hole (3) is arranged at the top of the large diameter section (3-1) and is located on the end surface of the tool handle (1); the closed end (3b) of the liquid nitrogen delivery hole (3) is arranged at the bottom of the small diameter section (3-2) and is located in the cutting portion (2); at least three liquid nitrogen guide grooves (1a) are provided on the end surface of the tool handle (1); each liquid nitrogen guide groove (1a) is connected to the open end (3a) of the liquid nitrogen delivery hole (3); a plurality of liquid nitrogen delivery side holes (3c) arranged at intervals are provided on the small diameter section (3-2) of the liquid nitrogen delivery hole (3) along the length direction; the liquid nitrogen delivery side holes (3c) are connected to the chip removal groove (2-3).

2. The milling cutter for composite material processing based on liquid nitrogen cooling according to claim 1, characterized in that: The liquid nitrogen conveying bypass holes (3c) at two adjacent chip removal grooves (2-3) are arranged in a staggered manner along the length direction of the cutting portion (2).

3. The milling cutter for composite material processing based on liquid nitrogen cooling according to claim 1, characterized in that: A plurality of chip breaking grooves (2a) arranged at intervals are provided on the main cutting edge (2-1).

4. The milling cutter for composite material processing based on liquid nitrogen cooling according to claim 1, characterized in that: The at least three liquid nitrogen guide grooves (1a) are evenly distributed along the radial direction on the end surface of the shank (1).

5. The milling cutter for composite material processing based on liquid nitrogen cooling according to any one of claims 1 to 4, characterized in that: The helix angle of the main cutting edge (2-1) is 5° to 8°.

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