Composite carbon layer for blade surface, method for manufacturing the same, and blade

Abstract

This application provides a composite carbon layer for the surface of a cutting tool, a method for manufacturing the same, and a cutting tool. The composite carbon layer includes alternating low-hardness carbon layers and high-hardness carbon layers deposited outward from the cutting tool surface, with at least two alternating deposition cycles, the hardness of the low-hardness carbon layer being 15 to 35 GPa, the hardness of the high-hardness carbon layer being 40 to 65 GPa, and the thickness ratio of the high-hardness carbon layer to the low-hardness carbon layer being 0.5 to 5.6. In this application, by alternating the low-hardness coating layer and the high-hardness coating layer and periodically embedding the low-hardness carbon layer into the high-hardness carbon layer, the accumulation of stress within the high-hardness carbon layer can be effectively mitigated, maintaining the overall stress of the coating layer at a relatively low level, avoiding the risk of collapse due to thick coating layer deposition, and ensuring high hardness and excellent wear resistance of the composite carbon layer while achieving thick film deposition. The composite carbon layer has a simple structure, stable performance, low cost, and a wide range of applications.

Description

Technical Field

[0001] This application relates to the field of cutting tool coating technology, for example, a composite carbon layer for the surface of a cutting tool, its manufacturing method, and a cutting tool.

Background Art

[0002] With the development of electronic products in the direction of thinning and portability, the dimensions of their printed wiring boards are gradually becoming smaller. However, with the development of information transmission in the direction of high frequency, high speed, and low loss, the ratio of hard fillers in the printed wiring board is gradually increasing, the dimensions of the holes in the printed wiring board are gradually becoming smaller, and the number of micropores is gradually increasing. Therefore, the dimensions of the micro drills for mechanical drilling are constantly breaking through the limit dimensions. As a result, the wear of the micro drills progresses, the discharge of chips becomes difficult, and in severe cases, the cutting tool breaks, affecting the processing efficiency and quality of the printed wiring board. Therefore, in order to improve the service life, it is necessary to improve the wear resistance of the micro cutting tool.

[0003] Coating technology is one of the most effective means to improve the surface performance of materials. The requirements for the performance of the coating layer usually include hardness, wear resistance, friction coefficient, etc. Conventional wear-resistant coating layers are usually metal coating layers or ceramic coating layers, such as TiAlN, CrAlN, or TiSiN. Although these coating layers have high hardness, they have insufficient wear resistance and large wear when machining difficult-to-machine materials. There is also a diamond coating layer in the conventional coating layer, but pretreatment is required for the manufacture of the diamond coating layer, so the strength of the cutting tool is significantly reduced, which may affect its life.

[0004] Diamond-like coating layers are a novel type of coating layer that possesses high hardness, good wear resistance, and a low coefficient of friction, and are widely used for processing the coating layers of cutting tools. However, their internal stress is relatively high, increasing the risk of collapse as the coating layer is thickened, making it impossible to manufacture very thick coating layers. As the dimensions of micro-drills decrease, the dimensions of the interface, which exhibits a unique shape on its surface, also decrease accordingly. The area that supports the growth of the coating layer gradually decreases, and the internal stress of the coating layer becomes excessive, making it prone to collapse and making it more difficult to reach the desired thickness. Therefore, in order to achieve the deposition of very thick coating layers on the surface of micro-drills, it is necessary to control the stress level of the entire coating layer.

[0005] CN104630708A discloses a diamond-like thick film, its manufacturing method, and a workpiece. This diamond-like thick film comprises, in order, a binding layer, a transition layer, and a diamond-like film layer laminated with diamond-like subfilms having different sp3 bond content. The manufacturing method involves depositing the binding layer and the transition layer on the surface of the workpiece, and then further depositing diamond-like subfilms with different sp3 bond content by changing the carbon ion energy or carbon-hydrogen ion energy. Here, the method of changing the ion or carbon-hydrogen ion energy is to apply a different bias voltage or bombard the surface of the already deposited diamond-like subfilm with high-energy inert gas particles. Although this diamond-like film also manufactured a multi-layer diamond-like subfilm, only two layers were arranged alternately, and the difference in sp3 bond content between adjacent two layers remained large, making it unfavorable for overall stress control and difficult to precisely control the manufacturing process.

[0006] CN105152548A discloses a method for manufacturing diamond-like film glass. This method includes the following steps: After placing a glass base sheet into a vacuum coating machine, a vacuum is created, argon gas is introduced to generate plasma, and plasma cleaning is performed. After vacuuming again and introducing argon gas, a carbon target radiation source is activated, and a pulsed DC power supply is turned on to deposit a diamond-like film on the surface of the glass substrate, in which diamond-like films with a high sp2 bond content and diamond-like films with a low sp2 bond content are deposited alternately. Finally, an AF film is deposited to obtain diamond-like film glass. This method only discloses that a pulsed DC power supply is used during the deposition of the diamond-like film, making it difficult to accurately control the ratio of sp2 to sp3 bonds.

[0007] As described above, when selecting a composite carbon layer on the blade surface, based on the characteristic that the internal stress of the diamond-like coating layer is relatively large, it is necessary to control the manufacturing process of the coating layer by alternately depositing carbon layers with low sp3 bond content and carbon layers with high sp3 bond content. This controls the overall stress level of the carbon layer, ensuring hardness and wear resistance while achieving the deposition of a thick coating layer. [Overview of the project] [Problems that the invention aims to solve]

[0008] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0009] The present invention aims to provide a composite carbon layer for the surface of a cutting tool, a method for manufacturing the same, and a cutting tool. The composite carbon layer is constructed by alternately arranging a low-hardness coating layer and a high-hardness coating layer, thereby effectively mitigating stress accumulation in the high-hardness coating layer and maintaining a low stress level throughout the coating layer. In order to ensure the high hardness and high wear resistance of the composite carbon layer, a large-thick film deposition of the composite carbon layer is achieved, making it less likely for the coating layer to break down and providing high stability. [Means for solving the problem]

[0010] In a first aspect, the present application provides a composite carbon layer for a cutting tool surface. The composite carbon layer comprises alternating low-hardness carbon layers and high-hardness carbon layers deposited outward from the cutting tool surface, wherein the alternating deposition is at least twice, for example, two, three, four, or five times. The hardness of the low-hardness carbon layer is 15 to 35 GPa, for example, 15 GPa, 18 GPa, 20 GPa, 22 GPa, 25 GPa, 28 GPa, 30 GPa, 32 GPa, or 35 GPa. The hardness of the high-hardness carbon layer is 40 to 65 GPa, for example, 40 GPa, 42 GPa, 45 GPa, 48 GPa, 50 GPa, 52 GPa, 55 GPa, 58 GPa, 60 GPa, or 65 GPa. The thickness ratio of the high-hardness carbon layer to the low-hardness carbon layer in the composite carbon layer is 0.5 to 5.6, for example, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or 5.6. However, it is not limited to the listed values, and other unlisted values ​​within each numerical range are also applicable.

[0011] In this invention, the structure of the composite carbon layer on the blade surface is selected by periodically alternating low-hardness carbon layers and high-hardness carbon layers according to the performance requirements. The former carbon layer has low sp3 bonding and low internal stress, while the latter carbon layer has high sp3 bonding and high internal stress. By periodically embedding low-hardness carbon layers in the high-hardness carbon layer, stress accumulation in the high-hardness carbon layer can be effectively mitigated, maintaining a low stress level for the entire coating layer. This avoids the risk of the coating layer becoming brittle due to its thickness, enables the deposition of large thickness films, and in particular enables the deposition of large thickness films on the complex surfaces of ultra-fine blades. At the same time, it ensures that the composite carbon layer has high hardness and excellent wear resistance. The composite carbon layer has a simple structure, stable performance, low cost, and a wide range of applications.

[0012] In this application, since the low-hardness carbon layer and the high-hardness carbon layer are arranged alternately, their thickness is an important factor affecting the performance of the composite carbon layer. In this application, the thickness ratio of the high-hardness carbon layer to the low-hardness carbon layer is controlled to 0.5 to 5.6. If the thickness ratio of the two is less than 0.5, the thickness of the high-hardness carbon layer becomes low, the overall hardness of the coating layer decreases, the wear resistance decreases, and the application requirements cannot be met. If the thickness ratio of the two exceeds 5.6, the thickness of the high-hardness carbon layer is too large, the low-hardness carbon layer cannot play a role in stress relaxation, and the coating layer becomes prone to crumbling during the thickening process.

[0013] In this application, the chemical composition and bonding state of the carbon layer, such as the content of sp3 and sp2 bonds, are analyzed using X-ray photoelectron spectroscopy (XPS). The depth-dependent changes and distribution of sp3 content in the carbon layer are characterized by depth profile analysis using a monochromatic AIX source. The hardness of the carbon layer is measured using a continuous stiffness mode nanoindenter. The radius of curvature of the carbon layer / substrate is determined using a laser device. The internal stress of the carbon layer is further calculated using the Stoney equation.

[0014] The following are preferred technical proposals for the present application, but are not intended to limit the technical proposals related to the present application. According to the following technical proposals, the technical objectives and beneficial effects of the present application can be better achieved and realized.

[0015] In the present invention, a preferred technical solution is one in which the total thickness of the composite carbon layer is 0.5 to 30 μm, for example 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, or 30 μm. However, the invention is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0016] Preferably, the thickness of a single high-hardness carbon layer is 0.03 to 2 μm, for example, 0.03 μm, 0.06 μm, 0.1 μm, 0.3 μm, 0.5 μm, 0.8 μm, 1 μm, 1.2 μm, 1.5 μm, 1.8 μm, or 2 μm, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0017] Preferably, the internal stress in both the low-hardness carbon layer and the high-hardness carbon layer is compressive stress.

[0018] Preferably, the internal stress of the low-hardness carbon layer is 0.2 to 3.8 GPa, such as 0.2 GPa, 0.5 GPa, 1.0 GPa, 1.5 GPa, 2.0 GPa, 2.5 GPa, 3.0 GPa, 3.5 GPa, or 3.8 GPa, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0019] Preferably, the internal stress of the high-hardness carbon layer is 8.3 to 15.6 GPa, such as 8.3 GPa, 9.0 GPa, 10.0 GPa, 11.0 GPa, 12.0 GPa, 13.0 GPa, 14.0 GPa, 15.0 GPa, or 15.6 GPa, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0020] In a preferred technical configuration of the present invention, the low-hardness carbon layer comprises a first low-hardness carbon layer and a second low-hardness carbon layer, wherein the first low-hardness carbon layer is closer to the base body side of the cutting tool, and the hardness of the first low-hardness carbon layer is lower than the hardness of the second low-hardness carbon layer.

[0021] Preferably, the hardness of the first low-hardness carbon layer is 15 to 25 GPa, for example 15 GPa, 16 GPa, 18 GPa, 20 GPa, 22 GPa, 24 GPa, or 25 GPa, and the hardness of the second low-hardness carbon layer is 25 to 35 GPa, for example 25 GPa, 26 GPa, 28 GPa, 30 GPa, 32 GPa, 34 GPa, or 35 GPa. However, the hardness is not limited to the listed values, and other unlisted values ​​within each numerical range are also applicable.

[0022] Preferably, the high-hardness carbon layer includes a first diamond-like coating layer and a second diamond-like coating layer, wherein the first diamond-like coating layer is closer to the base body side of the cutting tool, and the hardness of the first diamond-like coating layer is lower than the hardness of the second diamond-like coating layer.

[0023] Preferably, the hardness of the first diamond-like coating layer is 40 to 55 GPa, for example 40 GPa, 42 GPa, 45 GPa, 48 GPa, 50 GPa, 52 GPa, or 55 GPa, and the hardness of the second diamond-like coating layer is 55 to 65 GPa, for example 55 GPa, 56 GPa, 58 GPa, 60 GPa, 62 GPa, 64 GPa, or 65 GPa. However, the hardness is not limited to the listed values, and other unlisted values ​​within each numerical range are also applicable.

[0024] Preferably, the high-hardness carbon layer is a hydrogen-free diamond-like coating layer.

[0025] In the present application, the low-hardness carbon layer may be divided into an ultra-low-hardness carbon coating layer and a medium-low-hardness diamond-like coating layer, and the high-hardness coating layer may be divided into a medium-high-hardness diamond-like coating layer and an ultra-high-hardness diamond-like coating layer. The high-hardness carbon layer may have the same stress magnitude or may be composed of sub-layers with different stresses. The internal stress of each sub-layer satisfies 8.3 to 15.6 GPa, and the hardness is within the range of 40 to 65 GPa. Similarly, the low-hardness carbon layer may have the same stress or may be composed of sub-layers with different stresses. The internal stress of each sub-layer satisfies 0.2 to 3.8 GPa, and the hardness is within the range of 15 to 35 GPa. Preferably, the composite carbon layer further includes an adhesive layer located between the low-hardness carbon layer and the tool surface.

[0026] Preferably, the material of the adhesive layer includes any one or at least two combinations of a single substance, a nitride of the corresponding single substance, a carbide of the corresponding single substance, or a carbonitride of the corresponding single substance. Typical but non-limiting examples of the combination include a combination of a single substance and a nitride of the corresponding single substance, a combination of a nitride of the corresponding single substance and a carbide of the corresponding single substance, a combination of a carbide of the corresponding single substance and a carbonitride of the corresponding single substance, a combination of a single substance, a nitride of the corresponding single substance, and a carbide of the corresponding single substance, etc.

[0027] Preferably, the single substance includes any one or at least two combinations of chromium, titanium, molybdenum, tungsten, tantalum, vanadium, or silicon. Typical but non-limiting examples of the combination include a combination of chromium and titanium, a combination of tungsten and tantalum, a combination of titanium and silicon, a combination of molybdenum, tungsten, and tantalum, etc.

[0028] Preferably, the number of layers of the adhesive layer is at least one layer, such as 1 layer, 2 layers, or 3 layers, etc. The thickness of the adhesive layer is 0.1 to 5 μm, such as 0.1 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, or 5 μm, etc., but is not limited to the listed numerical values, and other unlisted numerical values within this numerical range are similarly applicable.

[0029] In the present application, an adhesive layer is provided between the composite carbon layer and the tool surface to enhance the bonding force between the two. As for the selection of the adhesive layer, one layer or multiple layers may be provided. In the case of multiple layers, combinations with different materials can be selected.

[0030] As a second aspect, the present application is a method for manufacturing the above-mentioned composite carbon layer, fixing the tool drill and evacuating, introducing a protective gas and controlling the pressure, activating the magnetron sputtering cathode and the magnetic field-controlled multi-arc cathode, controlling the current of the cathode, and depositing a low-hardness carbon layer on the surface of the tool drill in step (1); on the basis of step (1), reducing the current of the magnetron sputtering cathode and increasing the current of the magnetic field-controlled multi-arc cathode to obtain a high-hardness carbon layer by deposition in step (2); repeating the operations of step (1) and step (2), and continuously depositing the low-hardness carbon layer and the high-hardness carbon layer alternately to obtain a composite carbon layer in step (3). A manufacturing method is provided.

[0031] In this application, the content of sp3 and sp2 bonds in the composite carbon layer is adjusted by adjusting the ratio of carbon atoms to carbon ions that reach the blade surface. A higher ratio of carbon atoms results in a higher sp2 bond content in the coating layer, while a higher ratio of carbon ions results in a higher sp3 bond content. Carbon atoms are obtained from a magnetron sputtering cathode by glow discharge, and the higher the current or power of the magnetron sputtering cathode, the greater the amount of carbon atoms produced. Carbon ions are obtained from a magnetically tuned multi-arc cathode by arc discharge, and the higher the current or power of the magnetically tuned multi-arc cathode, the greater the amount of carbon ions produced. In other words, the ratio of carbon atoms to carbon ions needs to be synergistically controlled by the two types of cathodes. The magnetron sputtering cathode and the magnetically tuned multi-arc cathode form a certain angle, and the angle range can be selected from 20 to 180 degrees, for example, 20 degrees, 40 degrees, 60 degrees, 90 degrees, 120 degrees, 135 degrees, 150 degrees, or 180 degrees, and the angle of the central axes of the two intersects near the cutting surface to ensure that carbon atoms and carbon ions reach the surface simultaneously and do not deposit sequentially. In addition, the magnetron sputtering cathode and the magnetically tuned multi-arc cathode are arranged in pairs, and multiple pairs may be arranged and placed on the outer perimeter of the apparatus depending on the structure of the apparatus and the needs of the coating layer.

[0032] In a preferred technical application of the present invention, the cutting tool drill in step (1) is formed by grinding the surface of a cylindrical base body with a grinding wheel, and the material of the cylindrical base body includes hard alloys, high-speed steel, alloy steel, etc.

[0033] In one embodiment, cleaning, including ultrasonic cleaning, is performed before fixing the cutting tool drill in step (1).

[0034] In one embodiment, the medium used for cleaning comprises a liquid metal cleaning agent and water, and both are used in sequence.

[0035] In one embodiment, the liquid metal cleaning agent comprises one of the following: a sodium carbonate solution, a sodium hydroxide solution, a sodium phosphate solution, anisole solution, or an activated carbon solution.

[0036] In this invention, during cleaning, the cutting tool drills are sequentially immersed in a liquid metal cleaning agent and water. During the immersion process, ultrasonic waves are introduced into the container containing the metal cleaning agent and water, causing the liquid inside the container to vibrate and thoroughly clean impurities in the irregular and complex structures on the cutting tool surface. After that, the tool is placed in a dryer and dried.

[0037] In this application, the solutes of the above-mentioned liquid metal cleaning agent are divided into different types of substances. Among them, alkalis and sodium salts primarily utilize their alkalinity, anisole primarily utilizes its compatibility with organic substances, and activated carbon primarily utilizes its adsorption properties to perform the cleaning action on cutting tools and drills. Substances that do not undergo a chemical reaction when mixed with the above-mentioned substances may also be used in combination.

[0038] In one embodiment, the washing time is independently 10 to 40 minutes, for example, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, or 40 min, and is not limited to the listed numbers; other unlisted numbers within this range are also applicable.

[0039] In one embodiment, the cutting tool drill is cleaned and then dried.

[0040] In one embodiment, the cutting tool drill in step (1) is placed in a vacuum chamber and fixed to a jig.

[0041] In one embodiment, the pressure after the vacuuming in step (1) is reduced to 5.0 × 10⁻³ Pa or less, such as 5.0 × 10⁻³ Pa, 4.0 × 10⁻³ Pa, 3.0 × 10⁻³ Pa, 2.0 × 10⁻³ Pa, 1.0 × 10⁻³ Pa, or 8.0 × 10⁻⁴ Pa, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0042] In one embodiment, the protective gas in step (1) includes an inert gas.

[0043] In one embodiment, ion washing is performed before the deposition of the low-hardness carbon layer in step (1).

[0044] In one embodiment, the ion cleaning includes sputter cleaning of the blade surface with inert gas ions by glow discharge.

[0045] In one embodiment, during the washing of the ions, the pressure of the inert gas is controlled to 0.05 to 10 Pa, for example 0.05 Pa, 0.1 Pa, 0.5 Pa, 1 Pa, 3 Pa, 5 Pa, 8 Pa, or 10 Pa, the bias voltage is controlled to 100 to 10000 V, for example 100 V, 500 V, 1000 V, 2000 V, 3000 V, 5000 V, 6000 V, 8000 V, or 10000 V, and the current is controlled to 0.1 to 50 A, for example 0.1 A, 0.5 A, 1 A, 5 A, 10 A, 15 A, 20 A, 25 A, 30 A, 40 A, or 50 A, but the values ​​are not limited to those listed, and other unlisted values ​​within each numerical range are also applied.

[0046] In one embodiment, after washing the ions, the area is vacuumed again and an inert gas is introduced.

[0047] In this application, the ion cleaning mainly utilizes inert gas ions to thoroughly clean impurities and adsorbed air from the surface of the blade.

[0048] In one embodiment, the current of the magnetron sputtering cathode in step (1) is 20 to 50 A, such as 20 A, 25 A, 28 A, 30 A, 32 A, 36 A, 40 A, 45 A, or 50 A, and is not limited to the listed values, but other unlisted values ​​within this range are also applicable.

[0049] In one embodiment, the power of the magnetron sputtering cathode in step (1) is 5 to 20 kW, such as 5 kW, 6 kW, 8 kW, 10 kW, 12 kW, 14.5 kW, 16 kW, 17 kW, 18.5 kW, or 20 kW, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0050] In one embodiment, the current of the magnetically tuned multi-arc cathode in step (1) is 0.1 to 100 A, such as 0.1 A, 0.5 A, 1 A, 5 A, 10 A, 15 A, 20 A, 30 A, 50 A, 60 A, 80 A, or 100 A, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0051] In one embodiment, the power of the magnetically tuned multi-arc cathode in step (1) is 0.5 to 5 kW, such as 0.5 kW, 1 kW, 1.5 kW, 2 kW, 2.5 kW, 3 kW, 3.5 kW, 4 kW, 4.5 kW, or 5 kW, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0052] In one embodiment, when depositing the low-hardness carbon layer in step (1), the pressure is controlled to 0.1 to 5 Pa, for example, 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa, or 5 Pa, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0053] In one embodiment, the deposition time of the low-hardness carbon layer in step (1) is 1 to 300 min, such as 1 min, 3 min, 5 min, 10 min, 30 min, 50 min, 80 min, 120 min, 150 min, 200 min, 250 min, or 300 min, and is not limited to the listed numbers, but other unlisted numbers within this range are also applicable.

[0054] As a preferred technical method of the present invention, before depositing the low-hardness carbon layer in step (1), an adhesive layer is first deposited on the surface of the cutting tool drill.

[0055] In one embodiment, depending on the material of the adhesive layer, a magnetically adjustable multi-arc cathode is selected to control different atmospheric conditions and currents.

[0056] In one embodiment, when depositing the adhesive layer, the current of the magnetically tuned multi-arc cathode is 20 to 300 A, for example 20 A, 50 A, 70 A, 100 A, 120 A, 150 A, 180 A, 200 A, 220 A, 250 A, 270 A, or 300 A, and the pressure is controlled to 0.1 to 5 Pa, for example 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa, or 5 Pa, but is not limited to the listed values, and other unlisted values ​​within each numerical range are also applicable.

[0057] In one embodiment, when the adhesive layer is made of a single material, a protective gas is introduced to control the pressure.

[0058] In one embodiment, if the material of the adhesive layer is the nitride in question, nitrogen gas is introduced to control the pressure.

[0059] In one embodiment, when the material of the adhesive layer is the carbide of the relevant element, a carbon-containing gas is introduced to control the pressure.

[0060] In one embodiment, when the material of the adhesive layer is the carbonitride in question, a mixed gas of carbon-containing gas and nitrogen gas is introduced to control the pressure.

[0061] In one embodiment, the carbon-containing gas includes acetylene and / or methane.

[0062] In one embodiment, if there are two or more adhesive layers, the single-layer deposition processes described above are combined and superimposed.

[0063] In this application, the target material is added according to the type of adhesive layer, and the nitride, carbide, or carbonitride requires corresponding atmospheric conditions, such as a nitrogen-containing gas or a carbon-containing gas. For the former, nitrogen gas can be selected, and for the latter, a simple organic gas such as methane or acetylene can be selected.

[0064] In a preferred technical application of the present invention, the current of the magnetron sputtering cathode in step (2) is 0.1 to 20 A, such as 0.1 A, 0.5 A, 1 A, 3 A, 5 A, 8 A, 10 A, 12 A, 15 A, or 20 A, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0065] In one embodiment, the power of the magnetron sputtering cathode in step (2) is 0.5 to 5 kW, for example 0.5 kW, 1 kW, 1.5 kW, 2 kW, 2.5 kW, 3 kW, 3.5 kW, 4 kW, 4.5 kW, or 5 kW, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0066] In one embodiment, the current of the magnetically tuned multi-arc cathode in step (2) is 100 to 300 A, such as 100 A, 120 A, 150 A, 180 A, 200 A, 230 A, 250 A, 270 A, or 300 A, and is not limited to the listed values, but other unlisted values ​​within this range are also applicable.

[0067] In one embodiment, the power of the magnetically tuned multi-arc cathode in step (2) is 5 to 20 kW, such as 5 kW, 6 kW, 8 kW, 10 kW, 12 kW, 14 kW, 16 kW, 18 kW, or 20 kW, and is not limited to the listed values, but other unlisted values ​​within this range are also applicable.

[0068] In one embodiment, when depositing the high-hardness carbon layer in step (2), the pressure is controlled to 0.1 to 5 Pa, for example, 0.1 Pa, 0.5 Pa, 1 Pa, 1.5 Pa, 2 Pa, 2.5 Pa, 3 Pa, 4 Pa, or 5 Pa, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0069] In one embodiment, the deposition time of the high-hardness carbon layer in step (2) is 1 to 300 min, such as 1 min, 3 min, 5 min, 10 min, 30 min, 50 min, 80 min, 120 min, 150 min, 200 min, 250 min, or 300 min, and is not limited to the listed numbers, but other unlisted numbers within this range are also applicable.

[0070] In one embodiment, step (3) further involves alternately depositing a low-hardness carbon layer and a high-hardness carbon layer at least once, for example, once, twice, or three times.

[0071] In a third aspect, the present invention provides a cutting tool comprising a drill and the composite carbon layer, wherein the drill comprises a spiral groove, a peripheral edge and a drill tip, the spiral groove extending spirally from the drill tip toward the end of the drill, and the composite carbon layer is divided into three cases: completely covering the drill area, partially covering the drill area, or partially covering and then adding a lubricating coating layer.

[0072] In the present invention, a preferred technical example is a drill with a diameter of 0.075 to 6 mm, such as 0.075 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 6 mm, and is not limited to the listed values. Other unlisted values ​​within this range are also applicable, preferably 0.075 to 0.5 mm.

[0073] In one embodiment, the axial length of the helical groove is 80% or more of the length of the drill, such as 80%, 85%, 90%, 95%, or 100%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0074] In one embodiment, the number of helical grooves is at least one, for example, one, two, or three.

[0075] In one embodiment, the depth of the helical groove is 5 to 50% of the drill diameter, such as 5%, 10%, 15%, 20%, 25%, 30%, 40%, or 50%, but is not limited to the listed values, and other unlisted values ​​within this range are also applicable.

[0076] In the present invention, a preferred technical solution is that the composite carbon layer completely covers the drill area, meaning that it covers the helical groove, the outer cutting edge, and the drill tip.

[0077] In this application, this method requires the drill area to be completely covered. If the dimensions of the cutting tool are small and the coating layer that completely covers it, especially if the thickness of the coating layer is large, it will have a significant impact on the diameter of the drill, that is, on the chip evacuation capacity, and will easily cause the cutting tool to break. For this reason, this coating method is mainly applied to the processing of printed circuit boards, where the requirements for wear resistance are high and the requirements for chip evacuation are somewhat lower.

[0078] In one embodiment, the composite carbon layer partially covering the drill region means covering the outer cutting edge in the drill region.

[0079] In one embodiment, the length of the outer circumferential cutting edge covered with the composite carbon layer is 5 to 100% of the length of the helical groove, such as 5%, 10%, 20%, 30%, 40%, 50%, 60%, 80%, or 100%, and is not limited to the listed values; other unlisted values ​​within this range are also applicable.

[0080] In this invention, the composite carbon layer covers only the outer cutting edge of the drill. Depending on the workpiece material and drill structure, the length of the coating applied to the outer cutting edge extends from the drill tip towards the end of the helical groove, with a constant length ratio, and the composite carbon layer is not present on the surface of the helical groove or the drill tip. This coating method is mainly used for machining difficult-to-process printed circuit boards where the coating layer thickness is large and there are certain requirements for chip evacuation, improving wear resistance without affecting the chip evacuation capacity of the drill during deep hole drilling.

[0081] In one embodiment, adding a lubricating coating layer after partial covering means covering the outer cutting edge in the drill area and then depositing a single lubricating coating layer over the entire area.

[0082] In one embodiment, the thickness of the lubricating coating layer is 0.1 to 0.5 μm, for example, 0.1 μm, 0.15 μm, 0.2 μm, 0.25 μm, 0.3 μm, 0.35 μm, 0.4 μm, 0.45 μm, or 0.5 μm.

[0083] In this invention, a carbon layer with an ultra-low coefficient of friction that also provides wear resistance is deposited over the drill area in addition to the second type of coating layer application method. The coefficient of friction of this carbon layer is much lower than that of ordinary hard alloys (0.6-0.8). Such a structural design is mainly used for difficult-to-machine, high-grade printed circuit boards where the requirements for both the wear resistance and chip evacuation performance of the drill are extremely high. This low-friction coating layer has a small thickness and hardly affects the core thickness, and can effectively improve chip evacuation capacity.

[0084] In this application, the cutting tool is not limited to a double-edged micro-drill, but is also applicable to various commercially available standard and non-standard micro-drills, and can be selected for applications requiring high wear resistance and lubricity, such as milling cutters, reamers, broaches, molds, and gears. [Effects of the Invention]

[0085] Compared to related technologies, this invention has the following beneficial effects. (1) In this invention, by alternately arranging low-hardness coating layers and high-hardness coating layers and periodically embedding the low-hardness carbon layer in the high-hardness carbon layer, the accumulation of stress within the high-hardness carbon layer can be effectively alleviated, and the stress of the entire coating layer can be maintained at a relatively low level. This avoids the risk of the coating layer becoming easily broken down due to its thickness, and ensures that the composite carbon layer has high hardness and excellent wear resistance while achieving large film deposition.

[0086] (2) The composite carbon layer and cutting tools according to the present invention have a simple structure, stable performance, and can effectively solve the processing problems of difficult-to-process high-frequency printed circuit boards, high-speed printed circuit boards, and high-performance package substrates, and have a wide range of applications.

[0087] After reviewing and understanding the drawings and detailed descriptions, other embodiments can also be understood. [Brief explanation of the drawing]

[0088] The drawings provide a further understanding of the technical proposal described herein, constitute part of the explanatory document, and are used to illustrate the technical proposal described herein together with the embodiments of the present application, and are not intended to limit the technical proposal described herein.

[0089] [Figure 1] This is a schematic diagram of the structure of the composite carbon layer according to Example 1 of the present application. [Figure 2] This is a schematic diagram of the structure of the drill according to Embodiment 3 of the present application. [Figure 3] This is a cross-sectional view of the region near the tip of the drill in the drill structure according to Embodiment 3 of the present application. [Modes for carrying out the invention]

[0090] To better explain this application and facilitate understanding of its proposed technology, the application will be described in more detail below. However, the following examples are merely simplified illustrations of the application and do not represent or limit the scope of the claims; the scope of protection is governed by the claims.

[0091] The following are typical but non-limiting embodiments of the present invention. [Examples]

[0092] This embodiment provides a composite carbon layer for the surface of a cutting tool and a cutting tool. As shown in Figure 1, the schematic structure of the composite carbon layer includes, in order from the cutting tool surface outward, alternatingly deposited low-hardness carbon layer 1 and high-hardness carbon layer 2, with the number of alternating depositions being 2. The hardness of the low-hardness carbon layer 1 is 31 GPa, and the hardness of the high-hardness carbon layer 2 is 52 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 1.0.

[0093] The total thickness of the composite carbon layer is 1.1 μm.

[0094] The thickness of the single high-hardness carbon layer 2 is 0.25 μm.

[0095] The internal stresses of both the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are compressive stresses.

[0096] The internal stress of the low-hardness carbon layer 1 is 3.6 GPa, and the internal stress of the high-hardness carbon layer 2 is 12.6 GPa.

[0097] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12, wherein the first low-hardness carbon layer 11 is closer to the base body side of the blade, and the hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12. The hardness of the first low-hardness carbon layer 11 is 25 GPa, and the hardness of the second low-hardness carbon layer 12 is 35 GPa.

[0098] The high-hardness carbon layer 2 includes a first diamond-like coating layer 21 and a second diamond-like coating layer 22, wherein the first diamond-like coating layer 21 is closer to the base body side of the cutting tool, and the hardness of the first diamond-like coating layer 21 is lower than the hardness of the second diamond-like coating layer 22. The hardness of the first diamond-like coating layer 21 is 45 GPa, and the hardness of the second diamond-like coating layer 22 is 55 GPa.

[0099] The composite carbon layer further includes an adhesive layer 3 located between the low-hardness carbon layer 1 and the blade surface.

[0100] The material of the adhesive layer 3 is chromium, and the thickness of the adhesive layer 3 is 0.1 μm.

[0101] The cutting tool comprises a drill and a composite carbon layer on the surface of the drill, the drill comprises a helical groove 4, an outer cutting edge 5 and a drill tip 6, the helical groove 4 extends spirally from the drill tip 6 toward the end of the drill, and the composite carbon layer completely covers the drill area, i.e., covers the helical groove 4, the outer cutting edge 5 and the drill tip 6.

[0102] The diameter of the drill is 0.2 mm.

[0103] The axial length of the helical groove 4 is 100% of the drill length, there are two helical grooves 4, and the depth of the helical groove 4 is 28% of the drill diameter. [Examples]

[0104] This embodiment provides a composite carbon layer for the surface of a cutting tool and a cutting tool. The composite carbon layer includes, in order from the cutting tool surface outward, alternatingly deposited low-hardness carbon layer 1 and high-hardness carbon layer 2, with the number of alternating depositions being 3. The hardness of the low-hardness carbon layer 1 is 26 GPa, and the hardness of the high-hardness carbon layer 2 is 59 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 3.0.

[0105] The total thickness of the composite carbon layer is 1.2 μm.

[0106] The thickness of the single high-hardness carbon layer 2 is 0.3 μm.

[0107] The internal stresses of both the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are compressive stresses.

[0108] The internal stress of the low-hardness carbon layer 1 is 3.2 GPa, and the internal stress of the high-hardness carbon layer 2 is 13.1 GPa.

[0109] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12, wherein the first low-hardness carbon layer 11 is closer to the base body side of the blade, and the hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12. The hardness of the first low-hardness carbon layer 11 is 20 GPa, and the hardness of the second low-hardness carbon layer 12 is 30 GPa.

[0110] The high-hardness carbon layer 2 includes a first diamond-like coating layer 21 and a second diamond-like coating layer 22, wherein the first diamond-like coating layer 21 is closer to the base body side of the cutting tool, and the hardness of the first diamond-like coating layer 21 is lower than the hardness of the second diamond-like coating layer 22. The hardness of the first diamond-like coating layer 21 is 55 GPa, and the hardness of the second diamond-like coating layer 22 is 64 GPa.

[0111] The cutting tool comprises a drill and a composite carbon layer on the surface of the drill, the drill comprises a helical groove 4, an outer cutting edge 5 and a drill tip 6, the helical groove 4 extends spirally from the drill tip 6 toward the end of the drill, and the composite carbon layer completely covers the drill area, i.e., covers the helical groove 4, the outer cutting edge 5 and the drill tip 6.

[0112] The diameter of the drill is 0.25 mm.

[0113] The axial length of the helical groove 4 is 95% of the drill length, there are two helical grooves 4, and the depth of the helical groove 4 is 30% of the drill diameter. [Examples]

[0114] This embodiment provides a composite carbon layer for the surface of a cutting tool and a cutting tool. The composite carbon layer includes, in order from the cutting tool surface outward, alternatingly deposited low-hardness carbon layer 1 and high-hardness carbon layer 2, with the number of alternating depositions being 3. The hardness of the low-hardness carbon layer 1 is 20 GPa, and the hardness of the high-hardness carbon layer 2 is 55 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 4.0.

[0115] The total thickness of the composite carbon layer is 2.1 μm.

[0116] The thickness of the single high-hardness carbon layer 2 is 0.56 μm.

[0117] The internal stresses of both the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are compressive stresses.

[0118] The internal stress of the low-hardness carbon layer 1 is 2.8 GPa, and the internal stress of the high-hardness carbon layer 2 is 12.7 GPa.

[0119] The cutting tool comprises a drill and a composite carbon layer on the surface of the drill. A schematic diagram of the drill structure, as shown in Figure 2, includes a helical groove 4, an outer cutting edge 5, and a drill tip 6. A cross-sectional view of the region of the drill structure near the drill tip, as shown in Figure 3, shows that the helical groove 4 extends spirally from the drill tip 6 toward the end of the drill. After the composite carbon layer partially covers the drill region, a lubricating coating layer 7 is added, that is, after covering the outer cutting edge 5 in the drill region, the lubricating coating layer 7 is deposited over the entire surface.

[0120] The diameter of the drill is 0.36 mm.

[0121] The axial length of the helical groove 4 is 90% of the drill length, there are two helical grooves 4, and the depth of the helical groove 4 is 25% of the drill diameter.

[0122] Outer blade coated with the aforementioned composite carbon layer 5 The length is the spiral groove 4 It is 80% of the length.

[0123] The lubricating coating layer 7 had a thickness of 0.2 μm and covered the entire surface of the drill area. [Examples]

[0124] This embodiment provides a composite carbon layer for the surface of a cutting tool and a cutting tool. The composite carbon layer includes, in order from the cutting tool surface outward, alternatingly deposited low-hardness carbon layer 1 and high-hardness carbon layer 2, with four alternating deposition cycles. The hardness of the low-hardness carbon layer 1 is 17 GPa, and the hardness of the high-hardness carbon layer 2 is 50 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 5.5.

[0125] The total thickness of the composite carbon layer is 3.0 μm.

[0126] The thickness of the single high-hardness carbon layer 2 is 0.55 μm.

[0127] The internal stresses of both the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are compressive stresses.

[0128] The internal stress of the low-hardness carbon layer 1 is 1.5 GPa, and the internal stress of the high-hardness carbon layer 2 is 11.3 GPa.

[0129] The low-hardness carbon layer 1 includes a first low-hardness carbon layer 11 and a second low-hardness carbon layer 12, wherein the first low-hardness carbon layer 11 is closer to the base body side of the blade, and the hardness of the first low-hardness carbon layer 11 is lower than the hardness of the second low-hardness carbon layer 12. The hardness of the first low-hardness carbon layer 11 is 15 GPa, and the hardness of the second low-hardness carbon layer 12 is 25 GPa.

[0130] The high-hardness carbon layer 2 includes a first diamond-like coating layer 21 and a second diamond-like coating layer 22, wherein the first diamond-like coating layer 21 is closer to the base body side of the cutting tool, and the hardness of the first diamond-like coating layer 21 is lower than the hardness of the second diamond-like coating layer 22. The hardness of the first diamond-like coating layer 21 is 40 GPa, and the hardness of the second diamond-like coating layer 22 is 55 GPa.

[0131] The composite carbon layer further includes an adhesive layer 3 located between the low-hardness carbon layer 1 and the blade surface.

[0132] The adhesive layer 3 comprises a chromium adhesive layer and a chromium nitride adhesive layer in that order, with the chromium adhesive layer having a thickness of 0.2 μm and the chromium nitride adhesive layer having a thickness of 0.2 μm.

[0133] The cutting tool comprises a drill and a composite carbon layer on the surface of the drill, the drill comprises a helical groove 4, an outer cutting edge 5 and a drill tip 6, the helical groove 4 extends spirally from the drill tip 6 toward the end of the drill, and the composite carbon layer partially covers the drill region, i.e., covers the outer cutting edge 5 in the drill region.

[0134] The diameter of the drill is 0.4 mm.

[0135] The axial length of the helical groove 4 is 85% of the drill length, there is one helical groove 4, and the depth of the helical groove 4 is 40% of the drill diameter.

[0136] The length of the outer blade 5 covered with the composite carbon layer is 50% of the length of the helical groove 4. [Examples]

[0137] This embodiment provides a composite carbon layer for the surface of a cutting tool and a cutting tool. The composite carbon layer includes, in order from the cutting tool surface outward, alternatingly deposited low-hardness carbon layer 1 and high-hardness carbon layer 2, with four alternating deposition cycles. The hardness of the low-hardness carbon layer 1 is 15 GPa, and the hardness of the high-hardness carbon layer 2 is 40 GPa. The thickness ratio of the high-hardness carbon layer 2 to the low-hardness carbon layer 1 in the composite carbon layer is 0.5.

[0138] The total thickness of the composite carbon layer is 9.6 μm.

[0139] The thickness of the single high-hardness carbon layer 2 is 0.8 μm.

[0140] The internal stresses of both the low-hardness carbon layer 1 and the high-hardness carbon layer 2 are compressive stresses.

[0141] The internal stress of the low-hardness carbon layer 1 is 1.0 GPa, and the internal stress of the high-hardness carbon layer 2 is 9.8 GPa.

[0142] The cutting tool comprises a drill and a composite carbon layer on the surface of the drill, the drill comprises a helical groove 4, an outer cutting edge 5 and a drill tip 6, the helical groove 4 is the drill tip 6 The composite carbon layer extends spirally from the drill towards the end of the drill, and after the composite carbon layer partially covers the drill area, a lubricating coating layer 7 is added, that is, after covering the outer cutting edge 5 in the drill area, the lubricating coating layer 7 is deposited over the entire surface.

[0143] The diameter of the drill is 6 mm.

[0144] The axial length of the helical groove 4 is 80% of the drill length, there are two helical grooves 4, and the depth of the helical groove 4 is 20% of the drill diameter.

[0145] The length of the outer blade 5 covered with the composite carbon layer is 100% of the length of the helical groove 4.

[0146] The lubricating coating layer 7 has a thickness of 0.5 μm and covers the entire surface of the drill area. [Examples]

[0147] This embodiment provides a method for manufacturing a composite carbon layer for the surface of a cutting tool. The composite carbon layer is the composite carbon layer in Example 1, and the method includes the following steps.

[0148] (1) First, the drill bit was ultrasonically cleaned. The cleaning media used were sodium carbonate solution and water, both liquid metal cleaning agents. The two media were used in sequence, and the cleaning time for each was 30 minutes. After cleaning, the drill bit was dried, then placed in a vacuum chamber, fixed to a jig, and vacuum was created to reduce the pressure to 5.0 × 10⁻³ Pa. Argon gas was introduced, and the surface of the drill bit was ionically cleaned with argon ions using the glow discharge method. During ion cleaning, the argon gas pressure was controlled to 2.0 Pa, the bias voltage to 1000 V, and the current to 10 A.

[0149] After the ion cleaning, the system was vacuumed again, argon gas was introduced, the pressure was controlled to 2.0 Pa, a magnetically adjustable multi-arc cathode was started, the current of the magnetically adjustable multi-arc cathode was controlled to 60 A, and deposition was carried out on the surface of the cutting tool drill for 10 minutes to obtain a chromium adhesive layer.

[0150] Next, the pressure was controlled to 0.8 Pa, and the magnetron sputtering cathode and magnetically adjustable multi-arc cathode were activated. The current of the magnetron sputtering cathode was controlled to 10 A and the power to 12 kW, and the current of the magnetically adjustable multi-arc cathode was controlled to 50 A and the power to 1 kW. Deposition was carried out on the surface of the cutting tool drill for 4 minutes to obtain the first low-hardness carbon layer. Subsequently, the pressure was controlled to 0.8 Pa, and the current of the magnetron sputtering cathode was controlled to 8 A and the power to 10 kW, and the current of the magnetically adjustable multi-arc cathode was controlled to 80 A and the power to 2 kW. Deposition was carried out for 8 minutes to obtain the second low-hardness carbon layer.

[0151] (2) On the same basis as in step (1), the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled to 1A and 1kW for the magnetron sputtering cathode, and 250A and 12kW for the magnetically tuned multi-arc cathode. Deposition was carried out for 4 minutes to obtain the first diamond-like coating layer. Subsequently, the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled to 1A and 1kW for the magnetron sputtering cathode, and 280A and 15kW for the magnetically tuned multi-arc cathode. Deposition was carried out for 10 minutes to obtain the second diamond-like coating layer.

[0152] (3) The operations of steps (1) and (2) were repeated, and low-hardness carbon layers and high-hardness carbon layers were deposited alternately once to obtain a composite carbon layer that completely covered the drill area of ​​the cutting tool.

[0153] The cutting tool covered with a composite carbon layer was used to process HTG copper-clad sheet material, achieving a processing hole count of 30,000 mesh, while the cutting tool without the composite carbon layer could process to 3,000 mesh. In this embodiment, the processing life of the cutting tool covered with the composite carbon layer was improved to 10 times that of conventional tools. [Examples]

[0154] This embodiment provides a method for manufacturing a composite carbon layer for the surface of a cutting tool. The composite carbon layer is the composite carbon layer in Example 2, and the method includes the following steps.

[0155] (1) First, the drill bit was ultrasonically cleaned. The cleaning media used were sodium phosphate solution and water, both liquid metal cleaning agents. The two media were used in sequence, and the cleaning time for each was 20 minutes. After cleaning, the drill bit was dried, then placed in a vacuum chamber, fixed to a jig, and vacuum was created to reduce the pressure to 4.0 × 10⁻³ Pa. Argon gas was introduced, and the surface of the drill bit was ion-cleaned with argon ions using the glow discharge method. During ion cleaning, the argon gas pressure was controlled to 0.5 Pa, the bias voltage to 200 V, and the current to 50 A.

[0156] After the ion cleaning, the surface was vacuumed again, argon gas was introduced, and the pressure was controlled to 0.5 Pa. The magnetron sputtering cathode and the magnetically adjustable multi-arc cathode were started simultaneously. The current of the magnetron sputtering cathode was controlled to 50 A and the power to 20 kW, and the current of the magnetically adjustable multi-arc cathode was controlled to 100 A and the power to 0.5 kW. Deposition was carried out on the surface of the cutting tool drill for 25 minutes to obtain a first low-hardness carbon layer. Subsequently, the pressure was controlled to 0.5 Pa, the current of the magnetron sputtering cathode was controlled to 35 A and the power to 10 kW, and the current of the magnetically adjustable multi-arc cathode was controlled to 80 A and the power to 4 kW. Deposition was carried out for 35 minutes to obtain a second low-hardness carbon layer.

[0157] (2) Step ( 1 On the same surface, the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled, with the magnetron sputtering cathode current set to 0.5A and power to 0.5kW, and the magnetically tuned multi-arc cathode current set to 250A and power to 10kW. Deposition was carried out for 40 minutes to obtain the first diamond-like coating layer. Subsequently, the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled, with the magnetron sputtering cathode current set to 0.1A and power to 1kW, and the magnetically tuned multi-arc cathode current set to 300A and power to 20kW. Deposition was carried out for 60 minutes to obtain the second diamond-like coating layer.

[0158] (3) The operations of steps (1) and (2) were repeated, and low-hardness carbon layers and high-hardness carbon layers were deposited alternately twice to obtain a composite carbon layer that completely covered the drill area of ​​the cutting tool.

[0159] In this embodiment, the cutting tool covered with the composite carbon layer was used to process the low-CET package substrate HL 832NSF, and was able to process to 10,000 mesh with almost no wear on the drill tip after processing. However, the cutting tool without the coating layer experienced severe wear on the drill tip after processing to 4,000 mesh, which means the service life of the cutting tool is improved to 2.5 times that of conventional tools. [Examples]

[0160] This embodiment provides a method for manufacturing a composite carbon layer for the surface of a cutting tool. The composite carbon layer is the composite carbon layer in Example 3, and the method includes the following steps.

[0161] (1) First, the drill bit was ultrasonically cleaned. The cleaning mediums used were anisole solution, a liquid metal cleaner, and water. The two mediums were used in sequence, and the cleaning time for each was 20 minutes. After cleaning, the drill bit was dried, and then the drill bit was placed in a vacuum chamber, fixed to a jig, and vacuum was created to reduce the pressure to 5.0 × 10⁻³ Pa. Argon gas was introduced, and the surface of the drill bit was ion-cleaned with argon ions using the glow discharge method. During ion cleaning, the argon gas pressure was controlled to 5.0 Pa, the bias voltage to 2000 V, and the current to 1 A.

[0162] After the ion cleaning described above, the area was vacuumed again, argon gas was introduced, and the pressure was controlled to 0.2 Pa. A magnetron sputtering cathode and a magnetically adjustable multi-arc cathode were activated. The current of the magnetron sputtering cathode was controlled to 40 A and the power to 20 kW, and the current of the magnetically adjustable multi-arc cathode was controlled to 50 A and the power to 2 kW. Deposition was carried out on the surface of the cutting tool drill for 54 minutes to obtain a low-hardness carbon layer.

[0163] (2) In step (1), the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled, with the current of the magnetron sputtering cathode set to 3A and the power set to 1kW, and the current of the magnetically tuned multi-arc cathode set to 200A and the power set to 10kW. Deposition was carried out for 100 minutes to obtain a high-hardness carbon layer.

[0164] (3) The operations of step (1) and step (2) were repeated, and a low-hardness carbon layer and a high-hardness carbon layer were deposited alternately twice to obtain a composite carbon layer.

[0165] The composite carbon layer covered the position of the outer cutting edge in the drill region, followed by the deposition of a lubricating coating layer. The lubricating coating layer completely covered the drill region, and argon gas was introduced and the pressure controlled to 0.1 Pa. The currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled, with the current of the magnetron sputtering cathode controlled to 15 A and the power to 7.5 kW, and the current of the magnetically tuned multi-arc cathode controlled to 100 A and the power to 2 kW. Deposition was carried out for 10 minutes to obtain the lubricating coating layer.

[0166] In this embodiment, the blade covered with the composite carbon layer is used to process 6063 aluminum alloy and can process to 40,000 mesh. However, blades without the coating layer break after processing to 1,000 mesh due to thread winding and dust collection. This means that the service life of the blade is improved to 40 times that of conventional blades. [Examples]

[0167] This embodiment provides a method for manufacturing a composite carbon layer for the surface of a cutting tool. The composite carbon layer is the composite carbon layer in Example 4, and the method includes the following steps.

[0168] (1) First, the drill bit is ultrasonically cleaned. The cleaning media used are activated carbon solution and water, both liquid metal cleaning agents. The two media are used in sequence, and the cleaning time for each is 20 minutes. After cleaning, it is dried, and then the drill bit is placed in a vacuum chamber, fixed to a jig, and vacuum is created to reduce the pressure to 5.0 × 10⁻³ Pa. Krypton gas is introduced, and the surface of the drill bit is ionically cleaned with krypton ions using the glow discharge method. During ion cleaning, krypton The gas pressure was controlled to 3.0 Pa, the bias voltage to 5000 V, and the current to 0.1 A.

[0169] After the ion cleaning, the area was vacuumed again, krypton gas was introduced, the pressure was controlled to 3.0 Pa, and a magnetically adjustable multi-arc cathode was activated. The current of the magnetically adjustable multi-arc cathode was controlled to 90 A, and deposition was carried out on the surface of the cutting tool drill for 20 minutes to obtain a chromium adhesive layer. The gas introduced was adjusted to nitrogen gas, the pressure was controlled to 3.5 Pa, and the current of the magnetically adjustable multi-arc cathode was controlled to 90 A. Deposition was carried out for 15 minutes to obtain a chromium nitride adhesive layer.

[0170] Subsequently, the pressure was controlled to 0.3 Pa, and the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were started simultaneously. The current of the magnetron sputtering cathode was controlled to 30 A and the power to 8 kW, and the current of the magnetically tuned multi-arc cathode was controlled to 50 A and the power to 3 kW. Deposition continued for 10 minutes to obtain the first low-hardness carbon layer. Next, the pressure was controlled to 0.3 Pa, and the current of the magnetron sputtering cathode was controlled to 20 A and the power to 5 kW, and the current of the magnetically tuned multi-arc cathode was controlled to 70 A and the power to 5 kW. Deposition continued for 40 minutes to obtain the second low-hardness carbon layer.

[0171] (2) On the same basis as in step (1), the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled to set the current of the magnetron sputtering cathode to 0.8A and the power to 2.5kW, and the current of the magnetically tuned multi-arc cathode to 200A and the power to 8kW, and deposition was carried out for 12 minutes to obtain the first diamond-like coating layer. Subsequently, the currents of the magnetron sputtering cathode and the magnetically tuned multi-arc cathode were controlled to set the current of the magnetron sputtering cathode to 0.5A and the power to 1.8kW, and the current of the magnetically tuned multi-arc cathode to 250A and the power to 20kW, and deposition was carried out for 60 minutes to obtain the second diamond-like coating layer.

[0172] (3) The operations of steps (1) and (2) were repeated, and low-hardness carbon layers and high-hardness carbon layers were deposited alternately three times to obtain a composite carbon layer covering the outer cutting edge in the drill region.

[0173] In this embodiment, when a cutting tool covered with a composite carbon layer is used to process EM390 printed circuit boards, it can process to a mesh size of 2000. This is five times longer than conventional cutting tools that are only able to process to a mesh size of 400.

[0174] To summarize the above-described embodiment, the present invention alternately arranges low-hardness and high-hardness coating layers and periodically embeds the low-hardness carbon layer in the high-hardness carbon layer. This effectively alleviates stress accumulation within the high-hardness carbon layer, maintaining the overall stress level of the coating layer at a relatively low level. This avoids the risk of the coating layer becoming easily damaged due to its thickness, and ensures that the composite carbon layer has high hardness and excellent wear resistance while achieving large film deposition. The composite carbon layer and cutting tool have a simple structure, stable performance, and can effectively solve the processing problems of difficult-to-process high-frequency printed circuit boards, high-speed printed circuit boards, and high-performance package substrates, thus having a wide range of applications.

[0175] While the present application describes the detailed products and methods relating to this application with respect to the above-described embodiments, the applicant declares that this application is not limited to these detailed products and methods, meaning that this application cannot be implemented without relying on these detailed products and methods. Those skilled in the art should understand that any improvements to this application, equivalent substitutions to the products relating to this application, additions of auxiliary structures, and selection of specific methods are all included within the scope of protection and disclosure of this application. [Explanation of Symbols]

[0176] 1: Low-hardness carbon layer; 11: First low-hardness carbon layer; 12: Second low-hardness carbon layer; 2: High-hardness carbon layer; 21: First diamond-like coating layer; 22: Second diamond-like coating layer; 3: Adhesive layer; 4: Helical groove; 5: Outer edge; 6: Drill tip; 7: Lubricating coating layer.

Claims

1. A composite carbon layer for the surface of a cutting tool, The composite carbon layer comprises alternating layers of low-hardness carbon and high-hardness carbon deposited outward from the surface of the blade, wherein the alternating deposition is performed at least twice, the hardness of the low-hardness carbon layer is 15 to 35 GPa, the hardness of the high-hardness carbon layer is 40 to 65 GPa, and the thickness ratio of the high-hardness carbon layer to the low-hardness carbon layer in the composite carbon layer is 0.5 to 5.

6. Composite carbon layer.

2. The total thickness of the composite carbon layer is 0.5 to 30 μm. The composite carbon layer according to claim 1.

3. The thickness of the single high-hardness carbon layer is 0.03 to 2 μm. The composite carbon layer according to claim 1 or 2.

4. The internal stress in both the low-hardness carbon layer and the high-hardness carbon layer is compressive stress. A composite carbon layer according to any one of claims 1 to 3.

5. The internal stress of the low-hardness carbon layer is 0.2 to 3.8 GPa. Preferably, the internal stress of the high-hardness carbon layer is 8.3 to 15.6 GPa. A composite carbon layer according to any one of claims 1 to 4.

6. The low-hardness carbon layer comprises a first low-hardness carbon layer and a second low-hardness carbon layer, wherein the first low-hardness carbon layer is closer to the base body side of the blade, and the hardness of the first low-hardness carbon layer is lower than the hardness of the second low-hardness carbon layer. Preferably, the hardness of the first low-hardness carbon layer is 15 to 25 GPa, and the hardness of the second low-hardness carbon layer is 25 to 35 GPa. Preferably, the high-hardness carbon layer includes a first diamond-like coating layer and a second diamond-like coating layer, wherein the first diamond-like coating layer is closer to the base body side of the cutting tool, and the hardness of the first diamond-like coating layer is lower than the hardness of the second diamond-like coating layer. Preferably, the hardness of the first diamond-like coating layer is 40 to 55 GPa, and the hardness of the second diamond-like coating layer is 55 to 65 GPa. Preferably, the high-hardness carbon layer is a hydrogen-free diamond-like coating layer. Preferably, the composite carbon layer further includes an adhesive layer located between the low-hardness carbon layer and the blade surface. Preferably, the material of the adhesive layer includes one or at least two of the following: the element itself, a nitride of the element, a carbide of the element, or a carbonitride of the element. Preferably, the element comprises one or at least two of the following: chromium, titanium, molybdenum, tungsten, tantalum, vanadium, or silicon. Preferably, the number of adhesive layers is at least one, and the thickness of the adhesive layer is 0.1 to 5 μm. A composite carbon layer according to any one of claims 1 to 5.

7. A method for producing a composite carbon layer according to any one of claims 1 to 6, Step (1) involves fixing the cutting tool drill and creating a vacuum, introducing a protective gas to control the pressure, activating the magnetron sputtering cathode and magnetically tuned multi-arc cathode, and controlling the cathode current to deposit a low-hardness carbon layer on the surface of the cutting tool drill, Step (1) is followed by step (2), in which the current of the magnetron sputtering cathode is reduced and the current of the magnetically tuned multi-arc cathode is increased to obtain a high-hardness carbon layer by deposition. Step (3) includes repeating the operations of steps (1) and (2), and continuing to alternately deposit low-hardness carbon layers and high-hardness carbon layers to obtain a composite carbon layer. A method for manufacturing a composite carbon layer.

8. The cutting tool drill in step (1) is formed by grinding the surface of a cylindrical base body with a grinding wheel. The manufacturing method according to claim 7.

9. Before fixing the cutting tool drill in step (1), cleaning including ultrasonic cleaning is performed. Preferably, the medium used for the cleaning comprises a liquid metal cleaning agent and water, and both are used in sequence. Preferably, the liquid metal cleaning agent comprises one of the following: sodium carbonate solution, sodium hydroxide, sodium phosphate solution, anisole solution, or activated carbon solution. Preferably, the washing time is independently 10 to 40 minutes. Preferably, after cleaning the cutting tool drill, dry it. Preferably, the cutting tool drill in step (1) is placed in a vacuum chamber and fixed to a jig, Preferably, the pressure after the vacuuming in step (1) is reduced to 5.0 × 10⁻³ Pa or less. Preferably, the protective gas in step (1) includes an inert gas. Preferably, ion washing is performed before depositing the low-hardness carbon layer in step (1), Preferably, the ion cleaning includes sputter cleaning of the blade surface with inert gas ions by glow discharge, Preferably, during the ion cleaning, the pressure of the inert gas is controlled to 0.05 to 10 Pa, the bias voltage to 100 to 10000 V, and the current to 0.1 to 50 A. Preferably, after the ion cleaning, the system is vacuumed again and an inert gas is introduced. Preferably, the current of the magnetron sputtering cathode in step (1) is 20 to 50 A. Preferably, the power of the magnetron sputtering cathode in step (1) is 5 to 20 kW. Preferably, the current of the magnetically tuned multi-arc cathode in step (1) is 0.1 to 100 A. Preferably, the power of the magnetically tuned multi-arc cathode in step (1) is 0.5 to 5 kW. Preferably, during the deposition of the low-hardness carbon layer in step (1), the pressure is controlled to 0.1 to 5 Pa. Preferably, the deposition time of the low-hardness carbon layer in step (1) is 1 to 300 min. The manufacturing method according to claim 7 or 8.

10. Before depositing the low-hardness carbon layer in step (1), an adhesive layer is deposited on the surface of the cutting tool drill. Preferably, depending on the material of the adhesive layer, a magnetically adjustable multi-arc cathode is selected, and different atmospheric conditions and currents are controlled. Preferably, when depositing the adhesive layer, the current of the magnetically tuned multi-arc cathode is 20 to 300 A, and the pressure is controlled to 0.1 to 5 Pa. Preferably, if the adhesive layer is made of a single material, a protective gas is introduced to control the pressure. Preferably, if the material of the adhesive layer is the nitride in question, nitrogen gas is introduced and the pressure is controlled. Preferably, if the material of the adhesive layer is the carbide in question, a carbon-containing gas is introduced to control the pressure. Preferably, when the material of the adhesive layer is the carbonitride in question, a mixed gas of carbon-containing gas and nitrogen gas is introduced to control the pressure. Preferably, the carbon-containing gas includes acetylene and / or methane. Preferably, if the adhesive layer consists of two or more layers, the single-layer deposition processes described above are combined and superimposed. The manufacturing method according to any one of claims 7 to 9.

11. In step (2), the current of the magnetron sputtering cathode is 0.1 to 20 A. Preferably, the power of the magnetron sputtering cathode in step (2) is 0.5 to 5 kW. Preferably, the current of the magnetically tuned multi-arc cathode in step (2) is 100 to 300 A. Preferably, the power of the magnetically tuned multi-arc cathode in step (2) is 5 to 20 kW. Preferably, when depositing the low-hardness carbon layer in step (2), the pressure is controlled to 0.1 to 5 Pa. Preferably, the deposition time of the low-hardness carbon layer in step (2) is 1 to 300 min. Preferably, in step (3), a low-hardness carbon layer and a high-hardness carbon layer are subsequently deposited alternately at least once. The manufacturing method according to any one of claims 7 to 10.

12. A cutting tool comprising a drill and a composite carbon layer according to any one of claims 1 to 6, The drill includes a helical groove, an outer cutting edge, and a drill tip, wherein the helical groove extends spirally from the drill tip toward the end of the drill. The composite carbon layer can be divided into three cases: completely covering the drill area, partially covering the drill area, or partially covering the area and then adding a lubricating coating layer. Bladed weapon.

13. The diameter of the drill is 0.075 to 6 mm. Preferably, it is 0.075 to 0.5 mm. The blade according to claim 12.

14. The axial length of the helical groove is 80% or more of the length of the drill. Preferably, the number of helical grooves is at least one. Preferably, the depth of the helical groove is 5 to 50% of the diameter of the drill. The blade according to claim 12 or 13.

15. The composite carbon layer completely covering the drill area means that it covers the helical groove, the outer cutting edge, and the drill tip. Preferably, the composite carbon layer partially covering the drill region means covering the outer cutting edge in the drill region. Preferably, the length of the outer blade covered with the composite carbon layer is 5 to 100% of the length of the helical groove. Preferably, adding a lubricating coating layer after partial covering means that after covering the outer cutting edge in the drill area, one layer of lubricating coating is deposited over the entire area. Preferably, the thickness of the lubricating coating layer is 0.1 to 0.5 μm. A cutting tool according to any one of claims 12 to 14.

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