Edge layer, cutting tool, method of manufacture

Abstract

The application discloses a cutting edge layer, a cutter and a preparation method, relates to the technical field of wafer cutting cutters, and the cutting edge layer comprises a first composite layer, a second composite layer and a third composite layer which are sequentially arranged from inside to outside. The first composite layer is composed of coarse-grit diamond abrasive particles and a nickel-based bonding phase, the second composite layer is composed of coarse-fine mixed-grit diamond abrasive particles and a nickel-based bonding phase, and the third composite layer is composed of fine-grit diamond abrasive particles and a nickel-based bonding phase. The preparation method dynamically controls the concentration of diamond micropowder with different particle sizes through an electroforming process, and a gradient structure is constructed in situ. The application takes into account low damage in the early stage of the cutting edge and long service life in the middle and late stages, eliminates interface mutation between layers, improves structural stability and batch consistency, and is suitable for high-end wafer precision cutting scenes.

Description

Technical Field

[0001] This invention relates to the field of wafer dicing tool technology, and more particularly to a cutting edge layer, a cutting tool, and a preparation method. Background Technology

[0002] Wafer cutting tools are crucial for the precision cutting of brittle materials such as semiconductor wafers, compound semiconductor wafers, ceramic substrates, sapphire substrates, and silicon carbide substrates. Their cutting quality directly affects kerf width, chipping size, processing efficiency, yield, and the stability of subsequent packaging processes. Currently, wafer cutting tools typically employ an electroformed cutting edge structure formed by combining diamond abrasive grains with a nickel-based bonding layer. The high hardness and wear resistance of diamond enable high-precision cutting, while the nickel-based electroformed layer embeds and fixes the abrasive grains, ensuring sufficient strength, wear resistance, and service life of the cutting edge.

[0003] In wafer dicing applications, cutting tools typically feature ultra-thinness, small kerf width, high rotational speed, and high precision. The cutting edge layer thickness is generally controlled within the range of 10-40 μm, and the cutting edge must maintain high cutting sharpness throughout its entire lifespan while also minimizing edge chipping, sidewall damage, and long service life. Therefore, the grain size, distribution pattern, embedment depth, exposure height, and functional division of different layers of diamond abrasive grains in the electroformed cutting edge layer have a decisive impact on the overall performance of wafer dicing tools.

[0004] Existing electroforming wafer cutting tool technology mainly uses single-size diamond micropowder to randomly co-deposit in nickel-based electroforming solution to form the working cutting edge, that is, the diamond particle size is basically the same throughout the cutting edge layer (e.g., Figure 1 (as shown), or simply use a two-layer structure, such as first electroforming a coarser abrasive layer and then electroforming a finer abrasive layer, in order to balance cutting efficiency and surface quality (e.g. Figure 2 (As shown). However, with the increasing demands for low chipping, low damage, and high consistency in wafer dicing, traditional single-grain size or simple double-layer grain size structures are no longer sufficient to meet the requirements of current high-end wafer dicing applications.

[0005] The existing electroforming process for preparing the cutting edge of wafer hard tools generally adopts the following technical route: First, the annular metal substrate is pretreated by degreasing, activation, and pre-plating with nickel to ensure good conductivity and coating adhesion on the substrate surface. Then, the substrate is placed as the cathode in a nickel salt electroforming solution, and diamond micro powder of a single particle size is added to the electroforming solution. The diamond micro powder is kept in suspension in the electroforming solution by means of mechanical stirring, circulating stirring, or ultrasonic assistance. The co-deposition of the nickel layer and diamond micro powder is completed under a constant or segmented adjusted current density, and finally an electroformed cutting edge containing diamond abrasive grains is formed on the outer edge of the substrate.

[0006] Traditional solutions of this type typically have the following characteristics: The diamond abrasive grains used in the cutting edge layer have a single particle size, which remains basically unchanged throughout the electroforming process; The distribution of abrasive particles in the coating is mainly random embedding, lacking a clear particle size gradient design; Even if some technologies employ a two-layer granular structure, they often manifest as a simple superposition of "coarse-grained layer + fine-grained layer", with abrupt changes in the interlayer interface. During the electroforming process, the focus is on the total abrasive content, coating thickness, and bonding strength, with less emphasis on targeted design for the functional differences of different layers on the cutting edge. While the resulting cutting edge may meet general cutting requirements, it is often difficult to achieve a balance between sharpness in the initial cutting stage, sustained edge extension in the middle and later stages, quality of the cutting sidewall, and resistance to edge chipping.

[0007] The most similar traditional technical solutions to this patent can be regarded as two types of technical routes: "single-grain size random co-deposition to form electroformed cutting edge" and "coarse and fine double-layer simple superposition of electroformed cutting edge". The former is simple in process but lacks performance uniformity, while the latter, although an improvement over the former, still has problems such as discontinuous interlayer transition, insufficiently smooth gradient change, and unclear functional zoning.

[0008] The shortcomings of existing technologies can be summarized as follows: It is difficult to balance initial cutting sharpness with mid-to-late-stage lifespan: a single-grit cutting edge tends to perform similarly in the initial and mid-to-late stages of use, making it impossible to optimize for the needs of different cutting stages. Using finer-grit abrasives, while beneficial for reducing edge chipping and improving surface quality, results in relatively low cutting efficiency and insufficient abrasive grain extension. Conversely, using coarser-grit abrasives leads to higher cutting efficiency but can easily result in increased edge chipping, rougher kerf sidewalls, and decreased cutting stability.

[0009] The abrupt transition between layers in a simple double-layer structure can easily cause stress concentration and abrupt changes in cutting edge performance: Existing coarse and fine double-layer structures are usually two layers directly superimposed, with a lack of a continuous transition zone between the coarse and fine layers. This results in significant variations in the interlayer embedding depth, coating density, and internal stress distribution, which can easily lead to problems such as unstable bonding, local stress concentration, abrasive grain shedding, or sudden changes in cutting performance during use.

[0010] The embedding depth and exposure height of abrasive grains are difficult to control in a coordinated manner: In the traditional random co-deposition process, the embedding state of a single-size abrasive grains in the entire cutting edge layer is approximately the same. It is impossible to design different embedding ratios and exposure heights for the bearing layer near the substrate and the finishing layer near the outer surface, which may result in the cutting edge being too "dull" in the early stage of cutting, and then easily wearing out too quickly in the later stage due to insufficient support.

[0011] The unclear division of functions in the cutting edge layer makes it difficult to meet the requirements of high-precision wafer cutting: the cutting edge layer closer to the substrate needs stronger load-bearing capacity and abrasive grain holding force, while the cutting edge layer closer to the outer surface needs higher surface fineness and lower cutting damage. However, in the existing technology, the overall grain size and structure of the cutting edge layer are approximately the same, which cannot form a functional structure of "inner layer support, middle layer transition, and outer layer finishing".

[0012] Product consistency is greatly affected by process fluctuations: single-particle-size processes are sensitive to parameters such as abrasive concentration in the plating solution, stirring uniformity, and deposition time. Once local particles agglomerate, settle, or become unstable in suspension, it can easily cause local particle accumulation or particle loss in the cutting edge layer, resulting in increased batch-to-batch differences in tool cutting performance.

[0013] The reasons for this are as follows: existing technologies lack a layered grain size gradient design for the cutting edge: they only focus on abrasive deposition and do not match functional requirements according to the cutting edge depth; the grain size is single or double-layered abrupt, resulting in no smooth transition in cutting performance; abrasive grains are added in a coarse manner and the coating only controls the total thickness, without constructing a hierarchical microstructure; and the lack of an independent transition zone design exacerbates interlayer interface problems.

[0014] Therefore, it is necessary to develop a cutting edge layer, a cutting tool, and a preparation method to solve the above problems. Summary of the Invention

[0015] The purpose of this invention is to design a cutting edge layer, a cutting tool, and a preparation method to solve the above-mentioned problems.

[0016] The present invention achieves the above objectives through the following technical solutions: The cutting edge layer, consisting of layers arranged sequentially from the inside out: The first composite layer is used to enhance the overall load-bearing capacity and the continuous cutting capability in the middle and later stages; the first composite layer is formed by combining coarse-grained abrasive particles with a nickel-based bonding phase. A second composite layer is used to achieve a smooth transition in particle size; the second composite layer is formed by combining coarse and fine mixed-size abrasive particles with a nickel-based bonding phase; The third composite layer is used to reduce edge chipping in the early stage of cutting, improve the quality of the kerf sidewall and surface accuracy: The third composite layer is formed by combining fine-grained abrasive particles with a nickel-based bonding phase; the coarse and fine mixed-grained abrasive particles include coarse-grained abrasive particles and fine-grained abrasive particles.

[0017] Preferably, both the coarse and fine abrasive grains are diamond micron powder.

[0018] Preferably, the average particle size of the coarse abrasive grains is 2.5-4.0 μm; the average particle size of the fine abrasive grains is 0.8-2.0 μm; and the average particle size of the mixed coarse and fine abrasive grains is 1.2-3.0 μm.

[0019] Preferably, the thickness ratio of the first composite layer, the second composite layer, and the third composite layer is (2-4):(1-2):(0.5-1.5).

[0020] Preferably, the ratio of the average exposed edge height of the fine abrasive grains to the average particle size of the fine abrasive grains in the third composite layer is 20%-45%.

[0021] Cutting tools, including: Matrix; Electroforming the underlayer; the electroforming underlayer is formed on the working outer edge of the substrate; The cutting edge layer is formed on the outer side of the electroforming underlayer.

[0022] The method for preparing the cutting edge layer includes the following steps: S1. Tool substrate pretreatment: The tool substrate is mechanically shaped, degreased, activated and pre-plated with nickel in sequence to obtain the pretreated tool substrate; S2. Prepare gradient particle size electroforming solution: Prepare the basic electroforming solution of nickel salt system, and at the same time prepare coarse-grained abrasive and fine-grained abrasive. The coarse-grained abrasive is the first diamond micro powder, and the fine-grained abrasive is the second diamond micro powder. The two types of micro powder are pretreated and set aside. S3. Preparation of abrasive-free underlayer: The pretreated tool substrate is used as the cathode, and a pure nickel plate or nickel-containing anode is used as the anode. It is placed in an electroforming tank and abrasive-free electroforming deposition is carried out under preset temperature and current density conditions to form a pure nickel underlayer. S4. Preparation of the first composite layer: Add the first diamond micro powder to the nickel salt system basic electroforming solution, and co-deposit under preset temperature, current density, abrasive concentration and stirring conditions to form a first composite layer mainly composed of the first diamond abrasive. S5. Preparation of the second composite layer: While keeping the electroforming process continuous, gradually reduce the concentration of the first diamond powder in the basic electroforming solution of the nickel salt system and simultaneously increase the concentration of the second diamond powder. Co-deposit under preset temperature, current density and stirring conditions to form a second composite layer containing two types of diamond abrasive particles. S6. Preparation of the third composite layer: Adjust the proportion of abrasive particles in the basic electroforming solution of the nickel salt system, with the second diamond micro powder as the main component, and co-deposit under preset temperature, current density, abrasive particle concentration and stirring conditions to form a third composite layer with the second diamond abrasive particles as the main component. S7. Post-processing and shaping: The deposited cutting edge is slowly cooled, cleaned, shaped and its performance is tested to obtain a gradient particle size electroformed cutting edge layer.

[0023] Specifically, in step S1, the tool substrate is a metal substrate with good conductivity and dimensional stability; the surface roughness Ra of the area to be plated after mechanical shaping is controlled at 0.10-0.30μm; degreasing includes sequentially degreasing the tool substrate with organic solvent and alkaline degreasing; the degreased tool substrate is placed in an acidic activation solution for activation; the activated tool substrate is subjected to thin-layer pre-plating nickel treatment to form a transition conductive layer.

[0024] Preferably, in step S2, the nickel salt system basic electroforming solution comprises: Nickel sulfate: 280-320 g / L; Nickel chloride: 35-55 g / L; Boric acid: 35-45 g / L; Stress modifier: 0.5-2.0 g / L; Wetting agent: 0.03-0.20 g / L; Dispersant: 0.5-1.5 g / L; The pH value is controlled between 3.8 and 4.5; the average particle size of the first diamond micro powder is 2.5-4.0 μm; and the average particle size of the second diamond micro powder is 0.8-2.0 μm.

[0025] Furthermore, in step S4, the process conditions for preparing the first composite layer are as follows: Temperature: 38-42℃; Current density: 2.5-3.8 A / dm²; First diamond micron powder concentration: 10-25 g / L; Stirring method: a combination of mechanical stirring and intermittent ultrasonic dispersion; Deposition time: 20-50 min.

[0026] The thickness of the first composite layer formed during this stage is 5-12 μm.

[0027] In step S5, the process conditions for preparing the second composite layer are as follows: During the transition period of 10-40 minutes, the concentration of the first diamond micro powder was gradually reduced from 10-25 g / L to 3-10 g / L; at the same time, the concentration of the second diamond micro powder was gradually increased from 0-5 g / L to 8-18 g / L. Current density: 2.8-3.8 A / dm²; Temperature: 38-42℃; Stirring method: Maintain medium stirring intensity; The thickness of the second composite layer formed in this stage is 3-8 μm; In step S6, the process conditions for preparing the third composite layer are as follows: Second diamond powder concentration: 10-20 g / L; First diamond micron powder concentration: 0-5g / L; Temperature: 36-40℃; Current density: 2.0-3.0 A / dm²; Mixing method: Low-speed mechanical mixing; Deposition time: 10-30 min.

[0028] The thickness of the third composite layer formed in this stage is 1-5 μm.

[0029] The beneficial effects of this invention are as follows: Balancing initial cutting precision with mid-to-late-stage lifespan, this design solves the performance balancing problem: The cutting edge features a three-layer composite structure from the inside out, consisting of coarse, mixed, and fine grains. The inner coarse grain provides strong support and continuous cutting capability, while the outer fine grain ensures low edge chipping and low sidewall damage during initial cutting. As the cutting edge wears, the inner coarse grain gradually becomes visible, exhibiting excellent self-sharpening properties. This effectively solves the problem of not being able to balance the sharpness and lifespan of a single grain cutting edge, making it suitable for the high-precision, long-life cutting needs of high-end wafers.

[0030] Eliminating abrupt changes at the interlayer interface and improving the stability and reliability of the cutting edge structure: An independent mixed-grain transition layer is set between the coarse-grained layer and the fine-grained layer. Through the gradual change of abrasive concentration during the electroforming process, a continuous transition of grain size, coating density, and internal stress is achieved. This avoids the problems of stress concentration, unstable bonding, abrasive shedding, and sudden changes in cutting performance caused by abrupt changes at the interface of traditional double-layer structures, and significantly improves the overall stability and wear resistance of the cutting edge.

[0031] In-situ gradient structure construction improves batch consistency: By dynamically controlling the concentration ratio of diamond micro powder with different particle sizes during electroforming, gradient particle size cutting edges are formed in-situ without the need for subsequent processing and modification. Compared with the traditional coarse process with fixed particle size and fixed concentration, it effectively reduces the risks of abrasive agglomeration, sedimentation and uneven distribution, reduces the impact of process fluctuations on cutting edge performance, and significantly improves batch consistency of tool cutting performance.

[0032] Achieving precise coordination between grain size gradient and cutting edge function to adapt to high-precision cutting scenarios: Clearly defining the functional positioning of each layer of the cutting edge: the inner layer focuses on load-bearing and support, the middle layer focuses on smooth transition, and the outer layer focuses on fine cutting, so that the grain size gradient change matches the functional requirements in the cutting edge depth direction, forming a functional structure of "inner layer support - middle layer transition - outer layer fine cutting", which accurately meets the high-end scribing requirements of ultra-thin wafers, narrow kerf, and low damage.

[0033] Key parameters are controlled in synergy to balance abrasive grain retention force and cutting sharpness: By limiting the thickness ratio of the three-layer composite layer and the ratio of the exposed edge height of the outer abrasive grain to the grain size, the abrasive grain embedding depth and exposure height can be precisely controlled. This ensures that the nickel-based coating has a strong retention force on the abrasive grain, preventing premature abrasive grain detachment, while also ensuring that the cutting edge has excellent initial sharpness, further optimizing cutting quality and service life. Attached Figure Description

[0034] Figure 1 A schematic diagram of the cutting edge layer in existing technology 1; Figure 2 This is a schematic diagram of the cutting edge layer in the prior art 2; Figure 3 This is a schematic diagram of the cutting edge layer in this application; Figure 4 This is a schematic diagram of the structure of the first composite layer, the second composite layer, and the third composite layer in this application; Figure 5 This is a schematic diagram of the method for preparing the cutting edge layer in this application; Figure 6 This is a graph showing the concentration variation of diamond micron powder with different particle sizes during the electroforming process.

[0035] The markings in the diagram are explained as follows: 1. Matrix; 2. Cutting edge layer; 3. First composite layer; 4. Second composite layer; 5. Third composite layer; 6. Coarse abrasive grains; 7. Mixed coarse and fine abrasive grains; 8. Fine abrasive grains. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0040] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0041] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] like Figure 4 As shown, the cutting edge layer 2 includes the following components arranged sequentially from the inside out: The first composite layer 3 is used to enhance the overall load-bearing capacity and the continuous cutting capability in the middle and later stages; the first composite layer 3 is formed by combining coarse-grained abrasive grains 6 with a nickel-based bonding phase, and is used to enhance the overall load-bearing capacity and the continuous cutting capability in the middle and later stages; the first composite layer 3 is set close to the tool substrate 1 and serves as a load-bearing support layer; The second composite layer 4 is used to achieve a smooth transition in particle size variation; the second composite layer 4 is formed by combining coarse and fine mixed-size abrasive particles 7 with a nickel-based bonding phase; the second composite layer 4 is located outside the first composite layer 3 and is a gradient transition layer; The third composite layer 5, used to reduce edge chipping in the early stages of cutting and improve the quality of the kerf sidewalls and surface finish, is formed by combining fine-grained abrasive grains 8 with a nickel-based bonding phase. The mixed-grained abrasive grains 7 include coarse-grained abrasive grains 6 and fine-grained abrasive grains 8. The third composite layer 5 is located on the outermost side and serves as the finishing cutting layer. In some embodiments, both the coarse-grained abrasive grains 6 and the fine-grained abrasive grains 8 are diamond micron powder. The average particle size of the coarse-grained abrasive grains 6 is 2.5-4.0 μm; the average particle size of the fine-grained abrasive grains 8 is 0.8-2.0 μm; and the average particle size of the mixed coarse-fine abrasive grains 7 is 1.2-3.0 μm.

[0044] In some embodiments, the thickness ratio of the first composite layer 3, the second composite layer 4, and the third composite layer 5 is (2-4):(1-2):(0.5-1.5).

[0045] In some embodiments, the ratio of the average exposed height of the fine abrasive grains 8 in the third composite layer 5 to the average grain size of the fine abrasive grains 8 is 20%-45% to balance sharpness and holding power.

[0046] like Figure 3 As shown, the cutting tool includes: Matrix 1; Electroforming the underlayer; the electroforming underlayer is formed on the working outer edge of the substrate 1; Cutting edge layer 2; Cutting edge layer 2 is formed on the outer side of the electroforming underlayer.

[0047] like Figure 5 As shown, the preparation method of the cutting edge layer 2 includes the following steps: S1. Pretreatment of tool substrate 1: A ring-shaped metal tool substrate 1 is selected, preferably a stainless steel substrate 1, a high-strength alloy steel substrate 1, or a metal substrate 1 with good electrical conductivity and dimensional stability. To improve the adhesion between the subsequent nickel-based electroplated layer and the substrate 1, the pretreatment steps include: 1.1 Mechanical shaping and surface finishing The outer edge of the substrate 1 is precisely trimmed to ensure that its outer circle runout, end face flatness and reference thickness meet the design requirements; preferably, the surface roughness Ra of the area to be plated on the substrate 1 is controlled within the range of 0.10-0.30μm.

[0048] 1.2 Degreasing treatment The substrate 1 is subjected to organic solvent degreasing and alkaline degreasing in sequence to remove surface oil, polishing residue and particulate impurities; the alkaline degreasing temperature is preferably 45-60℃ and the treatment time is preferably 3-8min.

[0049] 1.3 Activation Treatment The degreased substrate 1 is placed in an acidic activation solution for activation to remove the oxide film and improve surface activity; the activation solution can be a dilute sulfuric acid solution, a dilute hydrochloric acid solution or other commonly used metal activation solutions, and the activation time is preferably 20-90s.

[0050] 1.4 Pre-plating nickel base The activated substrate 1 is subjected to a thin-layer pre-plating nickel treatment to form a transition conductive layer with a thickness of 0.5-2.0μm, so as to further improve the bonding stability between the electroformed cutting edge layer 2 and the substrate 1.

[0051] S2. Preparation of Gradient Particle Size Electroforming Solution: Prepare the basic electroforming solution of the nickel salt system, and establish gradient particle size deposition conditions by combining diamond micron powders of different particle sizes. The raw materials for preparing the basic electroforming solution of the nickel salt system are: based on 1L of deionized water. Nickel sulfate: 280-320g; Nickel chloride: 35-55g; Boric acid: 35-45g; Stress modifier: 0.5-2.0g; Wetting agent: 0.03-0.20g; Dispersant: 0.5-1.5g; The pH value should be controlled between 3.8 and 4.5; Simultaneously, coarse-grained abrasive grains 6 and fine-grained abrasive grains 8 are prepared. The coarse-grained abrasive grain 6 is the first type of diamond micro powder, and the fine-grained abrasive grain 8 is the second type of diamond micro powder. The average particle size of the first type of diamond micro powder is 2.5-4.0 μm, and the average particle size of the second type of diamond micro powder is 0.8-2.0 μm. Before being added to the electroforming solution, the first and second types of diamond micro powders undergo ultrasonic cleaning, surface drying, and dispersion pretreatment, respectively, to reduce agglomeration.

[0052] In some embodiments, a coarse-grained abrasive 6 suspension and a fine-grained abrasive 8 suspension can be prepared separately as needed, and the concentration ratio of the two types of abrasives in the plating solution can be dynamically adjusted during the electroforming process by adding them at different times or by quantitative replenishment.

[0053] S3. Preparation of abrasive-free underlayer: The pretreated tool substrate 1 is used as the cathode, and a pure nickel plate or a nickel-containing anode is used as the anode. It is placed in an electroforming tank and abrasive-free electroforming deposition is carried out under preset temperature and current density conditions to form a dense pure nickel underlayer. The process conditions are as follows: Temperature: 36-40℃; Current density: 1.5-3.0 A / dm²; Time: 8-20 minutes; Stirring method: low-speed mechanical stirring or circulating filtration stirring.

[0054] This step forms a pure nickel underlayer with a thickness of 1-3 μm, which serves as the bonding basis for subsequent gradient particle size composite layers.

[0055] S4. Preparation of the first composite layer 3: After completing the underlayer, the first diamond micro powder is added to the nickel salt system basic electroforming solution, and co-deposition is carried out under preset temperature, current density, abrasive concentration and stirring conditions to form the first composite layer 3 mainly composed of the first diamond abrasive. The process conditions are as follows: Temperature: 38-42℃; Current density: 2.5-3.8 A / dm²; First diamond micron powder concentration: 10-25 g / L; Stirring method: a combination of mechanical stirring and intermittent ultrasonic dispersion; Deposition time: 20-50 min.

[0056] During this stage, a first composite layer 3 is deposited, with a preferred thickness of 5-12 μm. The presence of coarser abrasive grains 6 in this layer helps to improve the coating's load-bearing capacity and subsequent continuous cutting ability, while also providing mechanical support for the outer layer's finishing structure.

[0057] S5. Preparation of the second composite layer 4: After the first composite layer 3 is formed, the electroforming process is continued, the concentration of the first diamond powder in the basic electroforming solution of the nickel salt system is gradually reduced, and the concentration of the second diamond powder is increased simultaneously. Under the preset temperature, current density and stirring conditions, the two types of diamond abrasive particles are co-deposited to form the second composite layer 4. The process conditions are as follows: During the transition period of 10-40 minutes, the concentration of the first diamond micron powder was gradually reduced from 10-25 g / L to 3-10 g / L; Simultaneously, the concentration of the second diamond micro powder was gradually increased from 0-5 g / L to 8-18 g / L; The current density is controlled at 2.8-3.8 A / dm²; Temperature should be controlled between 38-42℃; Maintain a stirring intensity of 600-800 RPM to prevent the stratification and sedimentation of coarse and fine abrasive particles.

[0058] This stage forms a second composite layer 4, with a preferred thickness of 3-8 μm. Since the second composite layer 4 contains abrasive grains of different sizes, a flexible transition can be formed in the microstructure, reducing interlayer stress abrupt changes and improving the bonding relationship between different functional layers.

[0059] S6. Preparation of the third composite layer 5: After the formation of the second composite layer 4, the proportion of abrasive particles in the nickel salt system's basic electroforming solution is adjusted, with the second diamond micropowder as the main component. Under preset temperature, current density, abrasive particle concentration, and stirring conditions, a third composite layer 5, mainly composed of the second diamond abrasive particles, is co-deposited to form. Figure 6 The figure shows the concentration variation curves of diamond micron powder with different particle sizes during the electroforming process. The process conditions are as follows: Second diamond powder concentration: 10-20 g / L; First diamond powder concentration: 0-5g / L, preferably no further addition is needed; Temperature: 36-40℃; Current density: 2.0-3.0 A / dm²; Stirring method: 300RPM-500RPM stirring intensity to reduce violent disturbance; Deposition time: 10-30 min.

[0060] This stage forms a third composite layer 5, with a preferred thickness of 1-5 μm. Since the outermost layer is mainly composed of finer abrasive grains 8, it can reduce the impact and edge chipping risk in the early stages of cutting, and improve the quality of the kerf sidewalls and processing stability.

[0061] S7. Post-processing and shaping: The deposited cutting edge is slowly cooled, cleaned, shaped and its performance is tested to obtain the gradient grain size electroformed cutting edge layer 2.

[0062] Specifically: Low-stress slow cooling avoids stress concentration in the electroformed layer caused by rapid temperature drop; Cleaning removes residual liquid and attached particles; If necessary, perform slight shaping, sharpening, or surface cleaning of the cutting edge to ensure that the cutting edge dimensions meet the target requirements; The final product is tested for cutting edge thickness, grain size distribution, exposed edge height, and cutting performance.

[0063] This application does not simply stack coarse abrasive layers and fine abrasive layers directly, but rather establishes a grain size gradient in the cutting edge thickness direction through a continuous configuration of "coarse bearing layer - coarse-fine mixed transition layer - fine finishing layer", giving the cutting edge the following characteristics: The area near the substrate 1 uses coarser abrasive grains 6 to enhance support and mid-to-late stage cutting ability; A grain size mixing transition zone is set in the middle to mitigate abrupt interface changes between different grain size layers; The outermost surface uses finer abrasive grains 8 to reduce initial cutting damage and improve edge chipping and sidewall quality; As the cutting edge wears down, the coarser abrasive grains 6 in the inner layer gradually become visible, allowing the tool to maintain good cutting efficiency and self-sharpening ability in the later stages of its lifespan.

[0064] Key Considerations for Production Process The two types of abrasive particles should be well dispersed to avoid secondary agglomeration of coarse and fine particles before addition; During the transition layer formation stage, it is essential to ensure a stable change in the concentration of the two types of abrasive particles, avoiding sudden changes that could lead to the formation of a distinct interface. During the electroforming process, the pH value, temperature and filtration cleanliness of the plating solution should be controlled to prevent pinhole defects caused by particle sedimentation and impurities. The current density should not be too high, otherwise it will reduce the surface quality of the fine-grained layer and cause the coating to be rough. If applied to ultra-thin wafer cutting, the thickness of the outer fine-grained region can be further reduced and its current density lowered to improve the surface finish of the cutting edge.

[0065] In some embodiments, a ring-shaped stainless steel tool substrate 1 with an outer diameter of 54 mm and an inner diameter of 40 mm is selected. The outer edge of the substrate 1 is mechanically trimmed to control the surface roughness Ra of the area to be plated to 0.18 μm. Subsequently, acetone degreasing, alkaline degreasing, and dilute acid activation treatment are performed in sequence, followed by a pre-plating of nickel with a thickness of approximately 1.0 μm.

[0066] Prepare a nickel salt electroforming base solution, based on 1L of deionized water, including: 300g / L nickel sulfate, 45g / L nickel chloride, 40g / L boric acid, 1.0g / L stress modifier, 0.08g / L wetting agent, and 0.8g / L dispersant, with the pH controlled at 4.1.

[0067] Prepare two types of diamond micro powder: The average particle size of the first diamond micro powder is 3.0 μm; The average particle size of the second diamond micro powder is 1.2 μm.

[0068] First, abrasive-free underlayer deposition was performed at 38°C and 2.2 A / dm² for 12 minutes to form a pure nickel underlayer of approximately 1.8 μm.

[0069] The process then proceeds to the preparation stage of the first composite layer 3. The first diamond micro powder is added to the electroforming solution at a concentration of 18 g / L and deposited at 40°C and 3.0 A / dm² for 28 min to form the first composite layer 3 with a thickness of about 7 μm.

[0070] Then, in the preparation stage of the second composite layer 4, the concentration of the first diamond powder is gradually reduced from 18 g / L to 6 g / L within 20 min during continuous electroforming, while the concentration of the second diamond powder is increased from 2 g / L to 12 g / L. The deposition continues for 22 min at 40℃ and 3.2 A / dm² to form the second composite layer 4 with a thickness of about 4 μm.

[0071] Finally, the third composite layer 5 is prepared. The addition of the first diamond powder is stopped, and the concentration of the second diamond powder is maintained at 14 g / L. The mixture is deposited at 38°C and 2.4 A / dm² for 16 min to form the third composite layer 5 with a thickness of about 2.5 μm.

[0072] After deposition, the wafer is slowly cooled, cleaned, and slightly shaped to obtain a wafer hard tool with a gradient grain size electroformed cutting edge.

[0073] Cross-sectional microscopic observation reveals that the cutting edge layer 2 forms a relatively clear load-bearing support zone, a mixed transition zone, and a surface finishing zone from the inside out, and there are no obvious abrupt interfaces between adjacent layers.

[0074] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A cutting edge layer, characterized in that, Including those set from the inside out: The first composite layer is used to enhance the overall load-bearing capacity and the continuous cutting capability in the middle and later stages; the first composite layer is formed by combining coarse-grained abrasive particles with a nickel-based bonding phase. A second composite layer is used to achieve a smooth transition in particle size; the second composite layer is formed by combining coarse and fine mixed-size abrasive particles with a nickel-based bonding phase; The third composite layer is used to reduce edge chipping in the early stage of cutting, improve the quality of the kerf sidewall and surface accuracy: The third composite layer is formed by combining fine-grained abrasive particles with a nickel-based bonding phase; the coarse and fine mixed-grained abrasive particles include coarse-grained abrasive particles and fine-grained abrasive particles.

2. The cutting edge layer according to claim 1, characterized in that, Both the coarse and fine abrasive grains are made of diamond micron powder.

3. The cutting edge layer according to claim 1, characterized in that, The average particle size of coarse abrasive grains is 2.5-4.0 μm; the average particle size of fine abrasive grains is 0.8-2.0 μm; and the average particle size of mixed coarse and fine abrasive grains is 1.2-3.0 μm.

4. The cutting edge layer according to claim 1, characterized in that, The thickness ratio of the first composite layer, the second composite layer, and the third composite layer is (2-4):(1-2):(0.5-1.5).

5. The cutting edge layer according to claim 1, characterized in that, In the third composite layer, the ratio of the average exposed edge height of the fine abrasive grains to the average grain size of the fine abrasive grains is 20%-45%.

6. Cutting tools, including: Matrix; Electroforming the underlayer; the electroforming underlayer is formed on the working outer edge of the substrate; The feature is that it further includes a cutting edge layer as described in any one of claims 1-5, the cutting edge layer being formed on the outer side of the electroformed underlayer.

7. The method for preparing the cutting edge layer according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Tool substrate pretreatment: The tool substrate is mechanically shaped, degreased, activated and pre-plated with nickel in sequence to obtain the pretreated tool substrate; S2. Prepare gradient particle size electroforming solution: Prepare the basic electroforming solution of nickel salt system, and at the same time prepare coarse-grained abrasive and fine-grained abrasive. The coarse-grained abrasive is the first diamond micro powder, and the fine-grained abrasive is the second diamond micro powder. The two types of micro powder are pretreated and set aside. S3. Preparation of abrasive-free underlayer: The pretreated tool substrate is used as the cathode, and a pure nickel plate or nickel-containing anode is used as the anode. It is placed in an electroforming tank and abrasive-free electroforming deposition is carried out under preset temperature and current density conditions to form a pure nickel underlayer. S4. Preparation of the first composite layer: Add the first diamond micro powder to the nickel salt system basic electroforming solution, and co-deposit under preset temperature, current density, abrasive concentration and stirring conditions to form a first composite layer mainly composed of the first diamond abrasive. S5. Preparation of the second composite layer: While keeping the electroforming process continuous, gradually reduce the concentration of the first diamond powder in the basic electroforming solution of the nickel salt system and simultaneously increase the concentration of the second diamond powder. Co-deposit under preset temperature, current density and stirring conditions to form a second composite layer containing two types of diamond abrasive particles. S6. Preparation of the third composite layer: Adjust the proportion of abrasive particles in the basic electroforming solution of the nickel salt system, with the second diamond micro powder as the main component, and co-deposit under preset temperature, current density, abrasive particle concentration and stirring conditions to form a third composite layer with the second diamond abrasive particles as the main component. S7. Post-processing and shaping: The deposited cutting edge is slowly cooled, cleaned, shaped and its performance is tested to obtain a gradient particle size electroformed cutting edge layer.

8. The method for preparing the cutting edge layer according to claim 7, characterized in that, In step S1, the tool substrate is a metal substrate with good conductivity and dimensional stability; the surface roughness Ra of the area to be plated after mechanical shaping is controlled at 0.10-0.30μm; degreasing includes sequentially degreasing the tool substrate with organic solvent and alkaline degreasing; the degreased tool substrate is placed in an acidic activation solution for activation; the activated tool substrate is subjected to thin-layer pre-plating nickel treatment to form a transition conductive layer.

9. The method for preparing the cutting edge layer according to claim 7, characterized in that, In step S2, the basic electroforming solution of the nickel salt system includes: Nickel sulfate: 280-320 g / L; Nickel chloride: 35-55 g / L; Boric acid: 35-45 g / L; Stress modifier: 0.5-2.0 g / L; Wetting agent: 0.03-0.20 g / L; Dispersant: 0.5-1.5 g / L; The pH value is controlled between 3.8 and 4.5; the average particle size of the first diamond micro powder is 2.5-4.0 μm; and the average particle size of the second diamond micro powder is 0.8-2.0 μm.

10. The method for preparing the cutting edge layer according to claim 7, characterized in that, In step S4, the process conditions for preparing the first composite layer are as follows: Temperature: 38-42℃; Current density: 2.5-3.8 A / dm²; First diamond micron powder concentration: 10-25 g / L; Stirring method: a combination of mechanical stirring and intermittent ultrasonic dispersion; Deposition time: 20-50 min; The thickness of the first composite layer formed during this stage is 5-12 μm; In step S5, the process conditions for preparing the second composite layer are as follows: During the transition period of 10-40 minutes, the concentration of the first diamond micro powder was gradually reduced from 10-25 g / L to 3-10 g / L; at the same time, the concentration of the second diamond micro powder was gradually increased from 0-5 g / L to 8-18 g / L. Current density: 2.8-3.8 A / dm²; Temperature: 38-42℃; Stirring method: Maintain medium stirring intensity; The thickness of the second composite layer formed in this stage is 3-8 μm; In step S6, the process conditions for preparing the third composite layer are as follows: Second diamond powder concentration: 10-20 g / L; First diamond micron powder concentration: 0-5g / L; Temperature: 36-40℃; Current density: 2.0-3.0 A / dm²; Mixing method: Low-speed mechanical mixing; Deposition time: 10-30 min; The thickness of the third composite layer formed in this stage is 1-5 μm.

Images