A monolithic micro-ceramic internal-cooling milling cutter for milling titanium alloys

Abstract

The present application relates to titanium alloy milling processing technical field, specifically relates to a kind of whole micro ceramic internal cooling milling cutter for milling titanium alloy.The material is titanium carbonitride-based micro-nano composite ceramic cutter material;The milling cutter is vertical milling cutter structure, including milling cutter body, milling cutter edge and milling cutter handle;In the milling cutter edge, radial rake angle is 8°~15°, axial rake angle is 8°~15°, first clearance angle is 10°~20°, second clearance angle is 20°~30°, the included angle between side cutting edge is unequal helix angle structure, the adjacent two end tooth cutter edges between bottom cutting edge are unequal tooth structure;Milling cutter axial center is internally arranged with internal cooling liquid passage.The milling cutter provided in the present application is beneficial to the reduction of cutting temperature in milling titanium alloy, reduces tool wear, can greatly improve tool life and processing efficiency.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy milling technology, and specifically to a solid micro-ceramic internal cooling milling cutter for milling titanium alloys. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] Titanium alloys are widely used in defense industry, aerospace and other fields due to their excellent properties such as high strength, lightweight and heat resistance. However, the excellent properties of titanium alloys also lead to poor machinability. For example, the ability of titanium alloys to maintain high strength at high temperatures poses a great challenge to cutting tools, making titanium alloys a typical difficult-to-machine material. The following problems exist when machining titanium alloys: (1) Due to the high yield strength and tensile strength of titanium alloys, the cutting force required during machining is greater, resulting in higher cutting temperatures. Compared with steel, at the same cutting speed, the cutting temperature of titanium alloys is more than twice that of steel; (2) Due to the high high-temperature chemical activity of titanium alloys, titanium will react chemically with most tool materials under high-temperature cutting, thereby aggravating adhesion and oxidative wear during the cutting process; (3) Due to the low thermal conductivity of titanium alloys, the tool-chip contact length is short, and the cutting heat is concentrated near the cutting edge and cannot be dissipated. Not only will it accelerate tool wear, but it will also affect the surface quality of the machined parts; (4) During milling, chips and fractures often appear on the cutting edge, and the cutting edge is subjected to dynamic impact, which will accelerate tool wear; (5) The low elastic modulus of titanium alloys makes the workpiece prone to elastic deformation during the machining process, resulting in a "springback" phenomenon, which causes chatter in the tool system; (6) In actual production, the cutting speed for machining titanium alloys is mostly between 30 and 60 m / min, which greatly limits the machining efficiency of titanium alloys. Therefore, how to reduce the cutting temperature of titanium alloys, reduce vibration, reduce tool wear, improve machining quality and efficiency, and achieve high-speed, high-quality and high-efficiency machining of titanium alloy materials has become an urgent technical problem to be solved.

[0004] Therefore, selecting appropriate tool structures and materials is crucial for machining titanium alloys. Current research indicates that ceramic tool materials possess high hardness and chemical stability; however, research on machining titanium alloys using integral micro-ceramic tools is scarce. This is primarily because ceramic tools have low fracture toughness, making them prone to fracture failure and unsuitable for cutting difficult-to-machine materials like titanium alloys. Furthermore, current titanium alloy machining tools often feature simple structures and rely heavily on external cooling, which hinders the reduction of cutting temperature in the tool-workpiece contact area. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a solid micro-ceramic internal cooling milling cutter for milling titanium alloys. This milling cutter is beneficial for reducing cutting temperature, minimizing tool wear, and improving tool life and machining efficiency.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] On one hand, a solid micro-ceramic internal coolant end mill for milling titanium alloys comprises, by weight percentage, the following raw materials: WC 10.0~30.0%, 3Y-ZrO2 5.0~25.0%, sintering aid 3.0~5.0%, and the balance being Ti(C) 0.7 N 0.3 ); among which, WC, sintering aid, Ti(C) 0.7 N 0.3 The particles of ) are in the micron range, while the particles of 3Y-ZrO2 are in the nano range. The sintering aids are Ni and Co. 3Y-ZrO2 is uniformly dispersed by a silane coupling agent.

[0008] The milling cutter is an end mill structure, including a cutter body, a cutting edge, and a shank. The cutting edge has a radial rake angle of 8°~15°, an axial rake angle of 8°~15°, a first clearance angle of 10°~20°, a second clearance angle of 20°~30°, and the included angle between the side cutting edges is an unequal helix angle structure. The bottom cutting edge has an unequal tooth splitting structure between two adjacent end teeth. An internal coolant channel is provided at the axial center of the milling cutter.

[0009] Previous research has provided a titanium carbonitride-based micro / nano composite ceramic cutting tool material, which possesses high hardness and high fracture toughness, effectively improving cutting performance and tool life; it also enhances the wear resistance and high-temperature chemical stability of milling tools. However, further research revealed that milling cutters formed using this material as a carrier struggle to achieve good machined surfaces on titanium alloys and still suffer from low tool life. Therefore, this invention further improves the structure of this cutting tool material.

[0010] First, because the material used in this invention has high hardness, it can effectively improve the wear resistance of the tool. Although its fracture toughness is high, the milling cutter without structural design still has chipping during the machining of titanium alloys, which leads to the milling cutter life not reaching the expected level. Therefore, this invention redesigns the radial rake angle γ, axial rake angle λ0, first clearance angle α1, and second clearance angle α2. This angle structure design can effectively suppress chipping and improve tool life while ensuring the sharpness of the cutting edge.

[0011] Secondly, due to the low elastic modulus of titanium alloys, chatter is prone to occur during machining after the above-mentioned angle design is adopted. Therefore, this invention sets the included angle between the side cutting edges to an unequal helix angle structure and the two adjacent end teeth of the bottom cutting edge to an unequal tooth division structure, so as to form a ceramic milling cutter with an unequal division and unequal helix angle structure. By changing the tooth pitch and helix angle distribution, the feed per tooth and the entry and exit cycles of each cutting tooth of the milling cutter are changed, thereby disrupting the distribution of the excitation force in the frequency domain, making the frequency domain energy of the milling cutter relatively dispersed, so as to reduce cutting vibration, improve cutting efficiency, and thus improve the surface quality of the machining.

[0012] Furthermore, although the above-mentioned angle design and unequal division helical angle structure can achieve the machining of titanium alloys, the high strength of titanium alloys leads to high cutting temperatures, resulting in severe tool wear and reduced tool life. Therefore, this invention sets an internal coolant channel in the axial center of the milling cutter, which can not only effectively increase the cooling rate, reduce the cutting temperature, reduce tool wear, and improve tool life, but also reduce the environmental pollution caused by the cooling and lubrication process.

[0013] On the other hand, an apparatus for milling titanium alloys includes the aforementioned milling cutter and milling machine, wherein the milling machine is a machine tool used to mill a workpiece with the milling cutter.

[0014] The beneficial effects of this invention are as follows:

[0015] (1) The present invention uses a new type of ceramic cutting tool material, which can improve the wear resistance and high temperature chemical stability of milling tools, effectively improve the milling performance of titanium alloys in precision machining, and help improve tool life and machining efficiency.

[0016] (2) Based on the use of a new type of ceramic cutting tool material, the present invention adopts a structure with unequal helix angle and unequal tooth pitch to suppress chatter during milling of titanium alloy, thereby reducing cutting force and making it easier to obtain a good machining surface.

[0017] (3) Based on the use of a novel ceramic tool material, this invention incorporates an internal cooling channel, which can effectively lubricate and cool the tool-workpiece contact area. This not only effectively increases the cooling rate, reduces cutting temperature, decreases tool wear, and improves tool life, but also reduces environmental pollution caused by the cooling and lubrication process. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0019] Figure 1This is a schematic diagram of the integral micro-ceramic internal cooling milling cutter structure for milling titanium alloys according to an embodiment of the present invention;

[0020] Figure 2 for Figure 1 Cross-sectional view of the end face geometry of the milling cutter;

[0021] Figure 3 This is a cross-sectional view of the end face of the unequal tooth pitch angle in an embodiment of the present invention;

[0022] Among them, 1. internal coolant channel, 2. milling cutter body, 3. milling cutter shank, 4. milling cutter cutting edge, 5. side cutting edge, 6. chip groove, 7. bottom cutting edge. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0025] In view of the problems of high cutting temperature, chatter, large tool wear and low machining rate in milling titanium alloys, this invention proposes an integral micro-ceramic internal cooling milling cutter for milling titanium alloys.

[0026] A typical embodiment of the present invention provides a solid micro-ceramic internal coolant milling cutter for milling titanium alloys. The material of the milling cutter, by weight percentage, comprises the following raw materials: WC 10.0~30.0%, 3Y-ZrO2 5.0~25.0%, sintering aid 3.0~5.0%, and the balance being Ti(C) 0.7 N 0.3 ); among which, WC, sintering aid, Ti(C) 0.7 N 0.3 The particles of ) are in the micron range, while the particles of 3Y-ZrO2 are in the nano range. The sintering aids are Ni and Co. 3Y-ZrO2 is uniformly dispersed by a silane coupling agent.

[0027] The milling cutter is an end mill structure, including a cutter body, a cutting edge, and a shank. The cutting edge has a radial rake angle of 8°~15°, an axial rake angle of 8°~15°, a first clearance angle of 10°~20°, a second clearance angle of 20°~30°, and the included angle between the side cutting edges is an unequal helix angle structure. The bottom cutting edge has an unequal tooth splitting structure between two adjacent end teeth. An internal coolant channel is provided at the axial center of the milling cutter.

[0028] In some embodiments, in the unequal helix angle structure, the angle between the helix angle and its adjacent helix angle is 35°~40° and 36°~41°, respectively. This angle of the unequal helix angle structure works better in conjunction with the unequal tooth structure.

[0029] In some embodiments, in the unequally divided tooth structure, the angle between the tooth and its adjacent tooth angle is 90°~100° and 80°~90°, respectively. This angle of the unequally divided tooth structure works better with the unequal helix angle structure.

[0030] In some embodiments, a helical chip groove is provided between the bottom cutting edge and the side cutting edge. The chip groove provides sufficient space for chip removal.

[0031] In one or more embodiments, the ratio of the outer diameter to the core diameter is 0.58 to 0.62. This configuration ensures sufficient chip space.

[0032] In some embodiments, the diameter of the milling cutter is 2-6 mm. It can be used for the finishing of micro-sized workpieces.

[0033] In some embodiments, the internal coolant channel is a single channel, and the diameter of the internal coolant channel is 9-11% of the diameter of the milling cutter. This configuration ensures that the milling cutter can mill titanium alloys normally while reducing the cutting temperature.

[0034] In some embodiments, the outlet of the internal coolant channel is located at the center of the end of the milling cutter.

[0035] In some embodiments, the milling cutter is a four-flute milling cutter.

[0036] Specifically, in the materials of this invention, WC 10.0~20.0% (preferably 13.0~17.0%), 3Y-ZrO2 5.0~15.0% (preferably 8.0~12.0%), sintering aid 3.0~5.0%, and the balance is Ti(C) 0.7 N 0.3The particle size of WC is 0.2~0.5μm, the particle size of the sintering aid is 1~2μm, and the particle size of 3Y-ZrO2 is 40~60 nm. The amount of silane coupling agent added is 0.5~1.5% of the weight of 3Y-ZrO2. The preparation process is as follows: 3Y-ZrO2 is added to the dispersion medium to form a suspension, then the silane coupling agent is added and stirred and / or ultrasonically dispersed to obtain a uniformly dispersed 3Y-ZrO2 dispersion; then Ti(C) is added... 0.7 N 0.3 WC and sintering aid are added to a 3Y-ZrO2 dispersion and stirred and / or ultrasonically dispersed to obtain a composite ceramic slurry. The composite ceramic slurry is then dried and sieved to obtain composite ceramic powder. The composite ceramic powder is pressed into shape and then vacuum hot-pressed for 30-75 min under the conditions of sintering pressure of 30-35 MPa, heating rate of 5-15℃ / min, and temperature of 1400-1600℃ to obtain the final product.

[0037] Another embodiment of the present invention provides an apparatus for milling titanium alloys, including the above-described milling cutter and milling machine, wherein the milling machine is a machine tool used to mill a workpiece using the milling cutter.

[0038] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below with reference to specific embodiments.

[0039] The following embodiments use a method for preparing the cutting tool material, and the steps are as follows:

[0040] (1) Using 0.5μm titanium carbonitride (Ti(C) 0.7 N 0.3 Using 0.25μm tungsten carbide (WC), 50nm zirconium oxide (3Y-ZrO2), 1μm cobalt (Co), and 1μm nickel (Ni) as raw materials, and based on 70.0Ti (C 0.7 N 0.3 The mass percentage mixture of 15.0WC-10.0(3Y)-ZrO2-3.0Co-2.0Ni was prepared; the nano-3Y-ZrO2 powder was weighed according to the proportion and anhydrous ethanol was used as the dispersion medium to prepare a suspension of nano-3Y-ZrO2 with a suspension concentration of 2.0 vol.%; then 1.0% of the mass of nano-3Y-ZrO2 silane coupling agent was added to the suspension as a dispersant; then it was mechanically stirred and ultrasonically dispersed for 30 min; then the micron-sized Ti(C) was weighed. 0.7 N 0.3 WC and sintering aid are added to a uniformly dispersed 3Y-ZrO2 suspension and ultrasonically stirred for 30 min; then loaded into a ball mill and wet-milled with zirconia balls for 48 h to obtain a uniformly dispersed composite ceramic slurry.

[0041] (2) The composite ceramic slurry obtained in step (1) is placed in a vacuum drying oven and dried at 120°C for 6 hours. Then it is cooled to room temperature and sieved through a 200-mesh sieve to obtain composite ceramic powder, which is then packaged for later use.

[0042] (3) Calculate the weight of the composite ceramic powder obtained in step (2) according to the size of the mold and the thickness of the sintered ceramic sample. Place the weighed composite ceramic powder into the mold, flatten it, and press it for 30 minutes in a cold press to form the shape.

[0043] (4) Place the pressed blank and mold obtained in step (3) into the hot pressing sintering furnace, and maintain the vacuum degree of the hot pressing sintering furnace at 10. -4 Below Pa, under a sintering pressure of 32 MPa, the temperature is increased to 1500℃ at 10℃ / min, held at that temperature and pressure for 45 min, and then cooled to room temperature with the furnace to obtain titanium carbonitride-based micro-nano composite ceramic cutting tool material.

[0044] Example

[0045] A solid micro-ceramic internal coolant milling cutter for milling titanium alloys, such as Figures 1-3 As shown, the integral micro-milling cutter comprises: a cutter body (2), a cutter shank (3), and a cutter cutting edge (4). The integral micro-milling cutter has a radial rake angle γ, an axial rake angle λ0, a first clearance angle α1, and a second clearance angle α2; wherein the radial rake angle is 8°-15°, the axial rake angle is 8°-15°, the first clearance angle is 10°-20°, and the second clearance angle is 20°-30°. A spiral-shaped chip groove (6) is provided between the bottom cutting edge (7) and the side cutting edge (5) of the integral micro-milling cutter. The cutter diameter D is 2mm-6mm, the ratio of the shank diameter (D) to the core diameter (d) is 0.6, and the cutter has an internal coolant channel (1) at the center position, the outlet of which is located at the center position of the cutter end, and the diameter of the internal coolant channel is D / 10. The included angle between the side cutting edges (5) of the integral micro milling cutter adopts an unequal helix angle structure, and the two adjacent end teeth of the bottom cutting edge (7) adopt an unequal tooth splitting structure, wherein the helix angles β1 and β3 are 35°-40°, and β2 and β4 are 36°-41°; the tooth angles θ1 and θ3 are 90°-100°, and the adjacent tooth angles θ2 and θ4 are 80°-90°. By adopting a new ceramic tool material, the tool structure is designed to address the difficult machining characteristics of titanium alloys. The tool structure with unequal helix angles and unequal tooth pitches is used to reduce chatter generated during the machining of titanium alloys. By designing a coolant channel inside the tool body, the cutting temperature and cutting force during the machining process are reduced. Combining the above design contents, the purpose of reducing tool wear, improving machining efficiency and tool life is achieved, and good cutting performance is realized.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A solid micro-ceramic internal cooling end mill for milling titanium alloys, characterized in that, The material of the milling cutter, by weight percentage, includes the following raw materials: WC 10.0~30.0%, 3Y-ZrO2 5.0~25.0%, sintering aid 3.0~5.0%, balance Ti(C) 0.7 N 0.3 ); among which, WC, sintering aid, Ti(C) 0.7 N 0.3 The particles of ) are in the micron range, while the particles of 3Y-ZrO2 are in the nano range. The sintering aids are Ni and Co. 3Y-ZrO2 is uniformly dispersed by a silane coupling agent. The milling cutter is an end mill structure, including a cutter body, a cutting edge, and a shank. The cutting edge has a radial rake angle of 8°~15°, an axial rake angle of 8°~15°, a first clearance angle of 10°~20°, a second clearance angle of 20°~30°, and the included angle between the side cutting edges is an unequal helix angle structure. The bottom cutting edge has an unequal tooth splitting structure between two adjacent end teeth. An internal coolant channel is provided at the axial center of the milling cutter.

2. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, In the unequal helix angle structure, the angles between the helix angle and its adjacent helix angle are 35°~40° and 36°~41°, respectively.

3. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, In the unequal tooth structure, the angle between the teeth and the angle between the adjacent teeth are 90°~100° and 80°~90°, respectively.

4. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, A helical chip groove is provided between the bottom cutting edge and the side cutting edge.

5. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 4, characterized in that, The ratio of the outer diameter to the core diameter is 0.58 to 0.

62.

6. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, The diameter of the milling cutter is 2~6 mm.

7. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, The internal coolant channel is a single channel, and the diameter of the internal coolant channel is 9-11% of the diameter of the milling cutter.

8. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, The outlet of the internal coolant channel is located at the center of the end of the milling cutter.

9. The integral micro-ceramic internal cooling milling cutter for milling titanium alloys as described in claim 1, characterized in that, The milling cutter is a four-flute milling cutter.

10. An apparatus for milling titanium alloys, characterized in that, The milling cutter and milling machine according to any one of claims 1 to 9, wherein the milling machine is a machine tool used to mill a workpiece using the milling cutter.

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