Cemented carbide milling cutter

Abstract

The utility model relates to cutter technical field, and disclose a kind of metal ceramic milling cutter, including coaxially fixed connection's shank assembly and cutter body assembly: cutter body assembly is based on metal ceramic base material layer, blade edge position composite tough coating (include aluminium titanium nitride transition layer and nanometer composite ceramic function layer), the variable parameter chip flute of spiral angle and groove depth gradual change is set in week surface, and slot wall evenly distributed heat dissipation hole;Shank assembly adopts 40CrNiMoA alloy steel material and is treated by nitriding, and inside along the axis is set with the cooling oil channel that is communicated with heat dissipation hole. Through composite coating, the impact resistance of blade edge is promoted, the chip removal efficiency is optimized by variable parameter chip flute, cooling oil channel and heat dissipation hole form high-efficiency heat dissipation system, positioning keyway, taper cooperation surface and end face positioning ring collaborative guarantee installation precision. The utility model structure design is reasonable, can extend cutter service life more than 50%, machining surface roughness is reduced to Ra0.8 μm below, radial runout is controlled within 0.005mm, effectively promote cutting efficiency and machining accuracy.

Description

Technical Field

[0001] This utility model relates to the field of cutting tool technology, specifically to a metal-ceramic end mill. Background Technology

[0002] Milling cutters are commonly used cutting tools in machining for milling operations. As industrial manufacturing develops towards higher precision, higher efficiency, and longer lifespan, the performance requirements for milling cutters are becoming increasingly stringent. Ceramic materials, possessing both the toughness of metals and the high hardness and wear resistance of ceramics, have become an important base material for high-end milling cutters. However, existing cermet milling cutters still have the following drawbacks in practical applications: Insufficient impact resistance: Most existing metal-ceramic end mills use a single metal-ceramic substrate, which has high hardness but poor toughness at the cutting edge. When cutting at high speed or machining hard and brittle materials, the cutting edge is prone to chipping or breakage due to impact load, which shortens the tool life and increases machining costs.

[0003] Low chip removal efficiency: Traditional milling cutters have chip grooves with equal depth and equal helix angle, which cannot adapt to the chip shape under different cutting parameters. This can easily lead to chip clogging of the chip grooves, which not only affects the surface roughness of the machined surface, but may also cause high temperature due to chip friction, thus aggravating tool wear.

[0004] Poor heat dissipation: The thermal conductivity of cermet materials is lower than that of metal cutting tools. Existing milling cutters lack targeted heat dissipation structures, making it difficult to quickly dissipate the heat generated during cutting. This results in excessively high cutting edge temperatures, which not only reduces the hardness of the tool but may also cause thermal deformation of the workpiece, affecting machining accuracy.

[0005] Low installation and positioning accuracy: The connection between the milling cutter and the tool holder often relies on tapered surface fit or simple keyway positioning. When rotating at high speed, radial runout or axial movement is prone to occur, which leads to increased cutting vibration, which not only reduces machining accuracy but also further shortens tool life.

[0006] Therefore, it is necessary to develop a new type of metal-ceramic end mill to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a metal-ceramic end mill to solve the problems mentioned in the background art.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a metal-ceramic end mill, comprising a shank assembly and a cutter body assembly, wherein one end of the shank assembly is fixedly connected to the cutter body assembly, and the shank assembly and the cutter body assembly are coaxially arranged; the cutter body assembly comprises a metal-ceramic substrate layer, the cutting edge of the metal-ceramic substrate layer is coated with a toughening coating, and a variable-parameter chip-receiving groove is formed on the peripheral surface of the cutter body assembly, the groove wall of the variable-parameter chip-receiving groove is provided with heat dissipation holes; the peripheral surface of the shank assembly is provided with a positioning keyway, and a cooling oil passage is formed at the end of the shank assembly away from the cutter body assembly, the cooling oil passage being connected to the heat dissipation holes.

[0009] Furthermore, the metal-ceramic substrate layer is composed of titanium carbide, titanium nitride, and a nickel-cobalt alloy binder phase, wherein the mass ratio of titanium carbide to titanium nitride is 7:3, and the mass ratio of the nickel-cobalt alloy binder phase is 15%-20%. This ratio can improve the toughness of the substrate while ensuring its hardness, thus preventing the substrate from easily breaking due to excessive hardness and brittleness.

[0010] Furthermore, the toughening coating includes a transition layer and a functional layer. The transition layer is an aluminum titanium nitride coating, which is attached to the surface of the metal ceramic substrate layer by physical vapor deposition to improve the bonding strength between the coating and the substrate. The functional layer is a nano-composite ceramic coating composed of alumina and zirconium oxide in a mass ratio of 8:2. It is covered on the surface of the transition layer by plasma spraying, which can improve the impact resistance of the cutting edge and reduce the friction coefficient of the cutting edge.

[0011] Furthermore, the variable parameter chip grooves are spirally distributed along the axial direction of the tool body assembly, and the spiral angle of the variable parameter chip grooves gradually increases from the tool holder assembly towards the cutting edge, with an angle range of 30°-45°. The groove depth gradually increases from the tool holder assembly towards the cutting edge, with a depth range of 2-4mm. This design can adapt the chip space according to the change in chip volume during the cutting process, avoiding chip clogging. At the same time, the gradual change in spiral angle can reduce cutting resistance and improve chip removal efficiency.

[0012] Furthermore, the heat dissipation holes are evenly distributed on the groove wall of the variable parameter chip groove, with a hole diameter of 1-1.5mm. The heat dissipation holes are connected to the oil guide branch inside the tool body assembly, and the oil guide branch is connected to the cooling oil channel. During cutting, the external cooling system supplies oil to the oil guide branch through the cooling oil channel. The lubricating oil is sprayed to the cutting area through the heat dissipation holes, which can quickly remove heat (which can reduce the cutting edge temperature by 80-120℃) and also achieve cutting edge lubrication, reducing wear.

[0013] Furthermore, the positioning keyway is a rectangular structure, with two symmetrically arranged on the circumferential surface of the tool holder assembly. The depth of the positioning keyway is 1 / 5 to 1 / 4 of the diameter of the tool holder assembly, and the width is 1.2 times the depth. The positioning keyway cooperates with the positioning key on the tool holder to limit the radial runout of the milling cutter (≤0.005mm). At the same time, the end of the tool holder assembly is provided with an end face positioning ring. The flatness of the end face positioning ring is ≤0.002mm, which can limit the axial movement of the milling cutter and improve the installation and positioning accuracy.

[0014] Furthermore, the tool holder assembly is made of 40CrNiMoA alloy steel, and the surface is nitrided (nitrided layer thickness 0.1-0.2mm, surface hardness HV≥800). The peripheral surface of the tool holder assembly is provided with a tapered mating surface (taper of 7:24), and the surface roughness Ra of the tapered mating surface is ≤0.4μm. The high-hardness nitrided layer can improve the wear resistance of the tool holder, and the 7:24 tapered mating surface is compatible with standard tool holders, ensuring stability during high-speed rotation.

[0015] Compared with the prior art, this utility model provides a top-mounted exhaust cooling device for electrical cabinets, which has the following beneficial effects: This cermet end mill uses a composite structure of "cermet substrate layer + toughening coating". The cermet substrate layer ensures the overall hardness and wear resistance of the tool, while the toughening coating improves the impact resistance of the cutting edge. This solves the problem of existing cermet end mills having insufficient impact resistance, which leads to easy chipping of the cutting edge and short life. It can extend the tool's service life by more than 50%.

[0016] This metal-ceramic end mill, through the design of a variable parameter chip flute, with the helix angle and flute depth gradually changing with the cutting area, adapts to the chip volume at different positions. At the same time, in conjunction with the cooling and lubrication effect of the heat dissipation holes, it solves the problems of low chip removal efficiency and easy clogging of existing end mills. It can improve chip removal efficiency by 40%, reduce chip scratches on the machined surface, and reduce the surface roughness Ra of the machined surface to below 0.8μm.

[0017] This cermet end mill, through a heat dissipation system consisting of cooling oil channels, oil guide branches, and heat dissipation holes, can quickly dissipate cutting heat, solving the problem of poor heat dissipation in existing cermet end mills that leads to high cutting edge temperature and decreased hardness. At the same time, the lubricating oil can reduce friction between the cutting edge and the chips, further reducing tool wear.

[0018] This metal-ceramic end mill, through a dual positioning structure of positioning keyway and end face positioning ring, combined with the high-precision tapered mating surface of the tool holder assembly, solves the problems of low installation positioning accuracy and easy runout during high-speed rotation of existing end mills. It can control radial runout within 0.005mm, improve machining accuracy, and avoid additional wear on the cutting edge caused by vibration. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the tool holder assembly structure of this utility model; Figure 3 This is a schematic diagram of the blade assembly structure of this utility model; Figure 4 This is a schematic diagram of the toughening coating structure of this utility model.

[0020] In the figure: 1. Tool holder assembly; 11. Locating keyway; 12. Cooling oil passage; 13. End face locating ring; 14. Tapered mating surface; 15. Oil guide branch; 2. Tool body assembly; 21. Metal-ceramic substrate layer; 22. Toughening coating; 221. Transition layer; 222. Functional layer; 23. Variable parameter chip groove; 24. Heat dissipation hole. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances. Example:

[0023] Please see Figure 1-4This utility model provides a technical solution: a metal ceramic end mill, including a shank assembly 1 and a cutter body assembly 2. One end of the shank assembly 1 is fixedly connected to the cutter body assembly 2 by vacuum welding. The coaxiality of the weld is ≤0.003mm, ensuring stability during high-speed rotation. The shank assembly 1 is made of 40CrNiMoA alloy steel, and its surface is nitrided with a nitriding layer thickness of 0.15mm and a surface hardness of HV850, which can improve the wear resistance of the shank and avoid wear on the mating surfaces caused by long-term installation and disassembly. The peripheral surface of the shank assembly 1 is provided with a tapered mating surface 14 with a taper of 7:24 and a surface roughness Ra of 0.2μm, which is compatible with standard shanks and ensures fitting accuracy.

[0024] The blade assembly 2 includes a cermet substrate layer 21, which is composed of titanium carbide (TiC), titanium nitride (TiN), and a nickel-cobalt alloy binder phase. The mass ratio of titanium carbide to titanium nitride is 7:3, and the mass ratio of the nickel-cobalt alloy binder phase is 18%. The substrate has a hardness of HRA93 and a toughness σ_b≥1200MPa, balancing hardness and fracture resistance. The cutting edge of the cermet substrate layer 21 is coated with a toughening coating 22, which includes a transition layer 221 and a functional layer 222. The transition layer 221 is an aluminum titanium nitride (AlTiN) coating with a thickness of 4μm, which is attached to the substrate surface by physical vapor deposition (PVD) and has a bonding strength ≥80MPa. The functional layer 222 is a nanocomposite ceramic coating composed of alumina and zirconium oxide in a mass ratio of 8:2, with a thickness of 2.5μm, which is covered by plasma spraying. The cutting edge impact resistance can reach 350MPa, and the friction coefficient is 0.28, which can effectively prevent the cutting edge from chipping.

[0025] The peripheral surface of the tool body assembly 2 has three variable-parameter chip grooves 23, which are spirally distributed along the axial direction. The spiral angle gradually changes from 30° to 45° from the tool holder assembly 1 towards the cutting edge, and the groove depth gradually changes from 2mm to 4mm. The variable parameter design can adapt to the chip space according to the change of chips from "thin and narrow" to "thick and wide" during the cutting process, and avoid chip blockage. The groove walls of the variable-parameter chip grooves 23 have heat dissipation holes 24 with a diameter of 1.2mm. Four heat dissipation holes 24 are evenly distributed on each chip groove wall. The heat dissipation holes 24 are connected to the oil guide branch 15 inside the tool body assembly 2. The oil guide branch 15 is connected to the cooling oil passage 12 of the tool holder assembly 1. During cutting, the external cooling system injects cutting oil into the oil guide branch 15 through the cooling oil passage 12. The cutting oil is sprayed onto the contact area between the cutting edge and the chips through the heat dissipation holes 24, which can reduce the cutting edge temperature from 600℃ to below 480℃ and lubricate the cutting edge to reduce friction and wear.

[0026] The tool holder assembly 1 has two symmetrically arranged locating keyways 11 on its circumferential surface. The locating keyways 11 are rectangular in structure, with a depth of 3mm (the depth is 1 / 5 of the diameter when the tool holder diameter is 15mm) and a width of 3.6mm. They cooperate with the locating key on the tool holder to limit the radial runout of the milling cutter to 0.004mm. The end of the tool holder assembly 1 away from the tool body assembly 2 has a cooling oil passage 12 with a diameter of 2mm. The end has an end face locating ring 13 with a flatness of 0.001mm. After it fits against the end face of the tool holder, it can limit the axial movement of the milling cutter and further improve the installation and positioning accuracy.

[0027] Working principle: When the metal-ceramic end mill is performing high-strength alloy cutting, it first mates with the standard tool holder through the tapered mating surface 14 of the tool holder assembly 1, the positioning keyway 11 mates with the tool holder positioning key, and the end face positioning ring 13 fits against the end face of the tool holder, achieving high-precision installation of the end mill and ensuring radial runout ≤0.005mm and axial runout ≤0.002mm. After starting the machining equipment, the external cooling system supplies oil through the cooling oil passage 12 and the guide oil branch 15. The lubricating oil is sprayed onto the cutting area through the heat dissipation hole 24. At the same time, the tool body assembly 2 rotates at high speed (up to 8000r / min), and the variable parameter chip groove 23... As it rotates, it generates a helical chip-removing force. Due to the gradual change in helix angle and groove depth, it can adapt to the volume change of the chip from the cutting edge to the tool holder, quickly removing the chip and avoiding blockage. During the cutting process, the functional layer 222 of the toughening coating 22 bears the impact load, the transition layer 221 ensures the bonding stability between the coating and the metal ceramic substrate layer 21, and the metal ceramic substrate layer 21 provides high hardness support. The three work together to ensure cutting accuracy (machined surface roughness Ra0.6μm) and extend tool life (60% longer than traditional metal ceramic end mills), making it suitable for precision machining scenarios of high-strength alloys in the aerospace field.

[0028] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. A metal-ceramic end mill, characterized in that, The tool includes a handle assembly (1) and a blade assembly (2). One end of the handle assembly (1) is fixedly connected to the blade assembly (2) and coaxially arranged. The blade assembly (2) includes a metal-ceramic substrate layer (21). The cutting edge of the metal-ceramic substrate layer (21) is coated with a toughening coating (22). A variable parameter chip-receiving groove (23) is provided on the peripheral surface of the blade assembly (2). A heat dissipation hole (24) is provided on the groove wall of the variable parameter chip-receiving groove (23). A positioning keyway (11) is provided on the peripheral surface of the handle assembly (1). A cooling oil passage (12) is provided at the end of the handle assembly (1) away from the blade assembly (2). The cooling oil passage (12) is connected to the heat dissipation hole (24).

2. The metal-ceramic end mill according to claim 1, characterized in that, The metal ceramic substrate layer (21) is composed of titanium carbide, titanium nitride and nickel-cobalt alloy binder phase, with the mass ratio of titanium carbide to titanium nitride being 7:3, the mass ratio of nickel-cobalt alloy binder phase being 15%-20%, and the substrate hardness HRA≥92.

3. The metal-ceramic end mill according to claim 1, characterized in that, The toughening coating (22) includes a transition layer (221) and a functional layer (222). The transition layer (221) is an aluminum titanium nitride coating with a thickness of 3-5 μm, which is attached to the surface of the metal ceramic substrate layer (21) by physical vapor deposition. The functional layer (222) is a nanocomposite ceramic coating composed of alumina and zirconium oxide in a mass ratio of 8:2, with a thickness of 2-3 μm, which is covered on the surface of the transition layer (221) by plasma spraying.

4. A metal-ceramic end mill according to claim 1, characterized in that, The variable parameter chip grooves (23) are spirally distributed along the axial direction of the cutter body assembly (2), and there are 3-4 of them. The spiral angle of the variable parameter chip grooves (23) gradually increases from the handle assembly (1) towards the cutting edge, with an angle range of 30°-45°. The groove depth gradually increases from the handle assembly (1) towards the cutting edge, with a depth range of 2-4mm.

5. A metal-ceramic end mill according to claim 1, characterized in that, The heat dissipation holes (24) are evenly distributed on the groove wall of the variable parameter chip groove (23), with a diameter of 1-1.5mm. The heat dissipation holes (24) are connected to the oil guide branch (15) inside the cutter body assembly (2), and the oil guide branch (15) is connected to the cooling oil channel (12).

6. A metal-ceramic end mill according to claim 1, characterized in that, The positioning keyway (11) is a rectangular structure, and there are two of them, which are symmetrically opened on the circumferential surface of the tool holder assembly (1). The depth of the positioning keyway (11) is 1 / 5 to 1 / 4 of the diameter of the tool holder assembly (1), and the width is 1.2 times the depth. The end of the tool holder assembly (1) is provided with an end face positioning ring (13), and the flatness of the end face positioning ring (13) is ≤0.002mm.

7. A metal-ceramic end mill according to claim 1, characterized in that, The tool holder assembly (1) is made of 40CrNiMoA alloy steel and its surface is nitrided. The thickness of the nitrided layer is 0.1-0.2mm and the surface hardness is HV≥800. The peripheral surface of the tool holder assembly (1) is provided with a tapered mating surface (14) with a taper of 7:24 and a surface roughness Ra≤0.4μm.

8. A metal-ceramic end mill according to claim 1, characterized in that, The handle assembly (1) and the blade body assembly (2) are fixedly connected by vacuum welding, and the coaxiality of the weld is ≤0.003mm.

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