High-strength and high-precision diamond tool and manufacturing method thereof

Abstract

The invention belongs to the technical field of diamond rollers, and particularly relates to a high-strength and high-precision diamond tool and a manufacturing method thereof. The method comprises the steps of designing and machining, ball milling and mixing, SPS hot pressing sintering, rough finishing, CVD diamond strip inlaying, gas shield induction brazing, heat treatment, precise finishing and the like. The W powder and the CuZn powder are subjected to high-energy ball milling treatment, active element powder such as Fe, Ni, Mn and Sn is added, and the spark plasma sintering process is combined, so that the compactness and the structure uniformity of an alloy blank are remarkably improved; the method comprises the following steps: filling powder in a female mold cavity of a graphite mold, performing cold press molding, performing SPS hot pressing sintering, performing rough finishing, dipping paste copper / silver-based brazing filler metal, and realizing metallurgical bonding between a CVD diamond strip and an alloy blank through induction brazing. The diamond tool prepared by the method has the characteristics of uniform distribution of the CVD diamond strips, good direction consistency, excellent wear resistance, high finishing efficiency and long service life, and is suitable for the high-precision machining field of gears, bearings, guide rails and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of diamond rollers, and in particular relates to a high-strength and high-precision diamond tool and a manufacturing method thereof. Background Art

[0002] Diamond rollers are a new generation of grinding wheel dressing tools, featuring high precision and high formability. They are highly efficient, long-lasting, and low-cost grinding wheel dressing tools used in specialized machine tools for high-volume form grinding and gear grinding. CNC form grinding technology has rapidly developed both domestically and internationally in recent years, and its efficient and precise processing methods have found widespread application in mechanical engineering. The diamond roller operates by being installed on the grinding machine's dressing device, where it copies the diamond roller's contour, accuracy, and dimensions onto the surface of the part being machined. The diamond roller is characterized by simple machine operation and low operator skill requirements. The processed products exhibit consistent precision and stable quality, significantly improving production efficiency and quality, reducing manufacturing costs, and facilitating automated grinding processes.

[0003] Spark Plasma Sintering (SPS) is a rapid sintering technology developed in recent years in the metallurgical field. It offers advantages such as rapid sintering, high density and uniformity, energy conservation and environmental protection, excellent material properties, a wide range of applications, ease of operation, the ability to prepare complex structural materials, and high cost-effectiveness. It significantly shortens production cycles, reduces energy consumption, and improves material properties. It is widely used in the preparation of a variety of materials, including metals, ceramics, and composites, and is an advanced sintering technology that is highly efficient, energy-efficient, and environmentally friendly.

[0004] Induction heating is characterized by the skin effect. During induction heating, the metal surface is heated rapidly, while the internal temperature rises more slowly. Continuous heating is required to gradually heat the metal internally through heat conduction.

[0005] Chinese patent publication number CN117165801A discloses a diamond roller sintering hot pressing process, which uses a metal binder including bonding material metals: titanium powder, iron powder, copper powder, so that it has the characteristics of liquid phase sintering, and skeleton material metals: tungsten powder, molybdenum powder, etc.; then the mixing, feeding, sintering, and trimming processes are carried out; the process is used to prepare the diamond roller through the rational configuration of the various component raw materials, so that the formed diamond roller has good hardness, toughness and wear resistance.

[0006] Chinese patent publication number CN114160798A discloses a diamond roller sintering hot pressing process. Diamond, copper powder, silver powder, cobalt powder and iron powder are placed in a roller barrel and stirred to obtain a mixed powder. A corresponding graphite mold is designed according to the roller's shape requirements. The mixed powder is placed in the graphite mold, vibrated and flattened, and then placed in a hot pressing sintering furnace for sintering. After completion, the semi-finished product is removed from the mold, demolded, and naturally cooled to obtain a finished product. The semi-finished product is then processed and trimmed to obtain a finished product.

[0007] Chinese patent publication number CN112621582A discloses a diamond roller sintering molding process for dressing grinding wheels. The main steps are: first, designing the diamond roller shape according to the shape, size and precision of the workpiece; then converting the designed roller shape into a negative mold; manufacturing a graphite mold based on the designed roller shape; first, applying a layer of adhesive on the surface of the inner cavity of the negative mold; using a vacuum suction pen to stick the diamond to the cavity surface; then placing the negative mold in the previously manufactured graphite mold; filling it with mixed tungsten powder, a metal binder skeleton material; pre-pressing it and sintering it in a furnace with a protective atmosphere; then infiltrating the bonding metal, melting it at high temperature and penetrating it into various parts of the binder along the capillaries of the binder; removing the mold; machining the hole and end face references based on the diamond profile; and dressing the grinding wheel on a grinding machine to obtain a diamond roller blank.

[0008] With the rapid development of high-speed grinding and ultra-high-speed grinding, the diamond sintered roller prepared by the method in the above patent document has a mechanical bonding force for the coating of the alloy blank on the diamond, and the bonding strength between the alloy blank and the abrasive is low. During heavy-load grinding, it may cause the abrasive to fall off and partial peeling of the alloy blank, which in turn leads to the overall failure of the dressing roller; the traditional mixing method mainly uses a three-dimensional rotation method to achieve uniform mixing of materials, and the densification degree of the sintered sample is low; the traditional roller is made using an one-piece molded graphite mold, and the process sequence is first bonding the CVD diamond strips, then filling powder and cold pressing, and sintering, which leads to uneven density of the roller alloy blank and poor hardness distribution uniformity, and the CVD diamond strips are prone to movement during the pressing process, resulting in inconsistent CVD strip spacing and up and down offsets, which in turn makes later dressing difficult, takes a long time, and may even lead to scrapping. Summary of the Invention

[0009] To solve the above problems, the present invention proposes a high-strength and high-precision diamond tool and a method for manufacturing the same. The high-energy ball milling process is used to treat W, CuZn, and active element powders such as Fe, Ni, Mn, and Sn, which can effectively accelerate the densification process. The spark plasma sintering process is combined to improve the sintering property of the alloy blank, thereby achieving a uniform and dense structure and excellent comprehensive performance. First, a negative mold cavity of a graphite mold is made, filled with alloy powder, and cold-pressed. Then, SPS sintering is performed to make the alloy blank. Compared with the traditional production method, the hardness uniformity of the alloy blank is better. After rough trimming, induction brazing is performed. The CVD diamond strip is then precisely trimmed, which not only has a fast trimming speed and high production efficiency, but also reduces the trimming wear of the CVD diamond strip. The CVD diamond strip is evenly distributed, has good directional consistency, and is beautiful. Paste copper / silver-based brazing filler metal is added between the CVD diamond strip and the alloy blank to achieve metallurgical bonding between the CVD diamond strip and the alloy blank with high bonding strength. Vacuuming and inert gas protection effectively reduce the oxidation of the alloy metal and CVD diamond, eliminate the need for flux, reduce pollution, and improve the corrosion resistance and mechanical properties of the product, thereby obtaining a higher quality diamond roller.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] A method for manufacturing a high-strength and high-precision diamond tool comprises the following steps:

[0012] (1) Design and processing

[0013] According to the designed roller shape, size and precision, CVD diamond strip size and CVD diamond strip arrangement, the negative mold cavity is converted into the negative mold cavity, and high-purity graphite and steel are machined to obtain the graphite mold negative mold cavity and steel substrate;

[0014] (2) Ball milling

[0015] Take the powder and ingredients, then put them into a mixer, seal them, ball mill them to obtain a mixture, dry them and set them aside;

[0016] (3) SPS hot pressing sintering

[0017] The mixed material is put into the negative mold cavity of the graphite mold, spread evenly, vibrated, and scraped flat, and then cold pressed. The steel substrate, the negative mold cavity, and the SPS sintering-upper pressing mold are then placed in the SPS sintering press and fixed. The press is vacuumed and filled with protective gas to form a protective atmosphere. The press is sintered under certain sintering temperature, sintering time, and sintering pressure conditions. After sintering, the press is cooled to room temperature to obtain a roller alloy blank.

[0018] (4) Rough trimming

[0019] Taking the roller alloy blank obtained by SPS hot pressing as the benchmark, the hole and end face benchmark are processed according to the designed roller shape, size and accuracy, and then the roller alloy blank is trimmed on the grinding machine;

[0020] (5)CVD diamond bar inlay

[0021] Dip the CVD diamond bar in a paste-like alloy solder and insert it into the gap reserved on the outer ring of the roller alloy blank. At the same time, apply a layer of paste-like alloy solder on the surface of the roller alloy blank near the CVD diamond bar and dry it.

[0022] (6) Gas shielded induction brazing

[0023] The roller alloy blank embedded with CVD diamond strips was assembled and fixed with a graphite jacket and upper and lower pressing molds, and then placed in a glove box. After evacuation, an inert protective gas was filled to form a protective atmosphere. A medium-frequency induction welder and a contour heater were used to heat, quench, and temper the CVD diamond strip area on the roller alloy blank.

[0024] (7) Precision finishing

[0025] The roller alloy blank is subjected to precision machining, polishing and ultrasonic cleaning to give it precise geometric dimensions, shape and beautiful surface, thus obtaining a CVD diamond roller product.

[0026] Specifically, the steel in step (1) is alloy steel or carbon steel; further, the alloy steel is 40Cr, and the carbon steel is 45# steel or S45C steel.

[0027] Specifically, in step (1), the graphite mold including the negative mold cavity is ground and polished.

[0028] Specifically, in step (1), the surface of the steel substrate is sandblasted to roughen the surface of the steel substrate and remove surface oxides, and then ultrasonic cleaning is performed to remove surface impurities and oil stains.

[0029] Specifically, when taking powder in step (2), the powder is taken according to the ratio of 60-80% by mass of W powder, 15-38% by mass of Cu70Zn30 powder, 0.3-3% by mass of Fe powder or Cu30Fe70 powder, 0.1-2% by mass of Ni powder or Cu30Ni70 powder, 0.5-1% by mass of Sn powder, and 1-3% by mass of Mn-Cu damping alloy powder.

[0030] Specifically, in step (2), the W powder has a particle size of 5-20 μm, the Cu70Zn30 powder has a particle size of 100-300 mesh, the Fe powder has a particle size of 5-10 μm, the Ni powder has a particle size of 5-10 μm, the Sn powder has a particle size of 200-400 mesh, the Mn-Cu damping alloy powder has a particle size of 200-300 mesh, the Cu30Fe70 powder has a particle size of 150-300 mesh, and the Cu30Ni70 powder has a particle size of 150-300 mesh.

[0031] Specifically, the batching and powder collection processes in step (2) are both carried out in a vacuum glove box and are performed under the condition of forming a protective atmosphere with a protective gas, wherein the protective gas is argon.

[0032] Specifically, in step (2), ball milling is performed in a ball mill of a mixer. During ball milling, the ball-to-material ratio is 5 to 10:1, the ball mill speed is 150 to 300 r / min, and the ball milling time is 20 to 30 h.

[0033] Specifically, in step (2), during ball milling, the grinding jar is made of any one of polyurethane, agate, stainless steel, cemented carbide, and zirconia; the grinding balls are made of any one of polyurethane, agate, stainless steel, cemented carbide, and zirconia.

[0034] Specifically, in step (2), the drying is performed in a vacuum drying oven at a temperature of 80 to 90° C. for 5 to 8 hours.

[0035] Specifically, in step (3), the protective gas is argon.

[0036] Specifically, in step (3), the cold pressing pressure is 70-100 MPa; the sintering temperature is 920-1000° C.; the sintering time is 1-10 min; and the sintering pressure is 15-30 MPa.

[0037] Specifically, during the rough trimming process in step (4), the difference between the processed size and the actual size is 0.01 to 0.04 mm.

[0038] Specifically, in step (5), CVD diamond bars are inlaid using a manual implantation method.

[0039] Specifically, in step (5), the surface of the CVD diamond bar is plated with Ti.

[0040] Specifically, in step (5), the paste alloy solder is a silver-based solder or a copper-based solder, and the melting point of the paste alloy solder is 780-870°C.

[0041] Further preferably, in step (5), the silver-based solder is Ag72CuTi solder, the copper-based solder is CuSn19Ti10 solder, the melting point of the Ag72CuTi solder is 780-810°C, and the melting point of the CuSn19Ti10 solder is 850-870°C.

[0042] Specifically, in step (5), the drying step is to use a vacuum drying oven to dry the paste-like alloy solder coated on the roller alloy blank, the drying temperature is 80-90° C., and the drying time is 0.5-1 h.

[0043] Specifically, in step (6), the inert protective gas is argon.

[0044] Specifically, in step (6), an infrared thermometer is used to measure the temperature during heating.

[0045] Specifically, in step (6), the specific steps of heating, quenching, tempering and other treatments are as follows: slowly heating to 400-500°C in the early stage, then adjusting the current to quickly heat the area near the CVD diamond bar to 840-900°C, keeping the temperature for 5-10 seconds to complete the welding between the CVD diamond bar and the roller alloy blank, then cooling to 650-710°C for quenching treatment, and then tempering treatment, the tempering temperature is 250-350°C, and the holding time is 1-2 hours.

[0046] Specifically, in step (6), the quenching liquid used during quenching is quenching oil.

[0047] Specifically, in step (7), after precision trimming, the precision size reaches ≤0.005mm.

[0048] Furthermore, in step (7), during packaging, the surface of the finished diamond roller is sprayed with anti-rust oil, wrapped with a protective film, sealed, and stored.

[0049] Furthermore, the present invention also provides a high-strength and high-precision diamond tool manufactured by the above method, wherein the diamond tool is a diamond roller, which has good performance in terms of strength, wear resistance and service life.

[0050] Specifically, the diamond roller is divided into a formed diamond roller and a diamond dressing disc. The diamond roller described in the present invention is a diamond dressing disc. The diamond dressing disc adopts point-contact axial feed dressing, which greatly improves the dressing accuracy and efficiency compared with the traditional single-point diamond dressing tool.

[0051] Furthermore, based on a general inventive concept, the present invention also provides applications of the manufactured high-strength and high-precision diamond tools in the processing of high-precision products such as gears, bearings and guide rails.

[0052] Compared with the prior art, the advantages of the present invention are:

[0053] 1. The present invention adopts high-energy ball milling to treat powder, selects W powder and CuZn alloy powder, and adds active element powders such as Fe, Ni, Co, and Sn, which can effectively accelerate the densification process and combine with the spark plasma sintering process to improve the sintering property of the alloy body, thereby achieving its uniform and dense organizational structure and excellent comprehensive performance.

[0054] 2. In the present invention, the addition of active metal elements such as Fe, Ni, Sn, and Mn greatly promotes the sintering process of the tungsten phase. Fe has limited solubility in Cu and can produce a stable intermediate phase with W at the sintering temperature, forming a large number of highly diffusible interface layers, which promotes the sintering of W in the solid phase particles; Ni dissolves more in Cu, so that the solubility of W in the liquid phase only increases slightly; Sn lowers the melting point and increases the hardness (the addition of Sn can form some intermetallic compounds, such as Cu3Sn, which are dispersed in the alloy body and play a strengthening role, thereby increasing the hardness and tensile strength of the alloy); Mn-Cu alloy has the effect of reducing vibration and noise.

[0055] 3. The present invention manufactures a toothed graphite mold female mold cavity, and the hardness uniformity of the roller alloy blank is good. At the same time, it can ensure that the CVD diamond strips are evenly distributed and have good directional consistency. The final roller is not only beautiful, but also has good wear resistance, long service life, and fast dressing speed.

[0056] 4. Copper-based brazing filler metal is added between the CVD diamond bar and the alloy blank to achieve chemical metallurgical bonding between the CVD diamond bar and the alloy blank with high bonding strength.

[0057] 5. Firstly, roughly trim the alloy blank, then fine trim the roller after brazing CVD diamond. The trimming speed is fast and efficient, and the wear of CVD diamond strip is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 This is a schematic diagram of the process flow of the diamond roller preparation process of the present invention;

[0059] Figure 2 It is a schematic diagram of cold pressing and SPS sintering assembly;

[0060] Figure 3 This is the assembly diagram for gas shielded induction heating;

[0061] Figure 4 This is a schematic diagram of the finished diamond roller;

[0062] Figure 5 This is the process of manufacturing diamond rollers using the traditional sintering method. DETAILED DESCRIPTION

[0063] The following is a clear and complete description of the technical solutions of this application in conjunction with the embodiments. Obviously, the embodiments described are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0064] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by those familiar with this technology. They are not used to limit the conditions for implementation of the present invention and therefore have no substantial technical significance. Any modification of the structure, change in the proportion relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose of the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0065] The process methods not specifically described in the following examples all adopt conventional technical means in the prior art.

[0066] In the following examples, room temperature or normal temperature refers to 25±5°C.

[0067] Example 1

[0068] Example 1 provides a method for making a high-strength and high-precision diamond tool, such as Figure 1 As shown, the diamond tool is a diamond roller, and the specific steps are as follows:

[0069] A: Design and processing: According to the designed roller shape, size and precision, CVD diamond bar size, and CVD diamond bar arrangement, the negative mold cavity is converted, and high-purity graphite (C≥99.9%) and 45# steel are machined to obtain the graphite mold negative mold cavity and 45# steel substrate. The surface of the machined 45# steel substrate is sandblasted to roughen the steel substrate surface and remove surface oxides, and then ultrasonically cleaned to remove surface impurities and oil stains. The graphite mold negative mold cavity is ground and polished for use (the machining method of high-purity graphite and 45# steel in the present invention, as well as the sandblasting, grinding, grinding and polishing and other processing methods can all adopt conventional methods in the prior art, and are not the inventive point of the present invention, so they will not be repeated).

[0070] B: Ball milling mixing: The mixture for roller sintering alloy blanks was prepared. The mixing and powdering processes were all carried out in a vacuum glove box filled with argon atmosphere. Specifically, the mixture was prepared and mixed according to the weight percentage of 70% W powder, 27.5% Cu70Zn30 alloy powder (Guangzhou Metal Metallurgical Group Co., Ltd., 80-100 mesh), 0.5% Fe powder, 0.5% Ni powder, 0.5% Sn powder, and 1% Mn-Cu damping alloy powder (Beijing Institute of High-tech Materials, 200-300 mesh). The mixture was then loaded into the ball mill jar of the mixer, sealed with tape, and the powder was treated with a high-energy ball milling process to achieve uniform mixing to obtain a mixture. Finally, the mixture was placed in a vacuum drying oven for drying and set aside.

[0071] In the high-energy ball milling process, the ball milling medium is anhydrous ethanol, the grinding jar is a polyurethane ball milling jar, the grinding ball material is natural agate, the ball-to-material ratio is 10:1, the ball mill speed is 300 r / min, the direction is reversed once every 30 minutes, and the ball milling time is 20 hours;

[0072] The vacuum drying temperature is 80°C and the drying time is 6 hours;

[0073] The W powder has a particle size of 5-20 μm, the Cu70Zn30 alloy powder has a particle size of 100-300 meshes, the Fe powder has a particle size of 5-10 μm, the Ni powder has a particle size of 5-10 μm, the Sn powder has a particle size of 200-400 meshes, and the Mn-Cu damping alloy powder has a particle size of 200-300 meshes.

[0074] C: SPS hot pressing sintering: put the mixed material into the negative mold cavity of the graphite mold, spread it evenly, vibrate it, scrape it flat, and then cold press it into shape. The cold pressing pressure at room temperature is 80MPa and the pressure is maintained for 30s.

[0075] The 45# steel substrate, the negative mold cavity, the SPS sintering-upper pressing mold, etc. are then placed in an SPS sintering press (60T-SPS spark plasma sintering press) and fixed (the specific equipment and components used in the SPS hot pressing sintering are conventional equipment in this field and are not the inventive point of the present invention, so they will not be described in detail). The press is evacuated and then filled with argon. The sintering temperature, sintering time, and sintering pressure are adjusted to appropriate parameters, and sintering is started. After sintering is completed, the press is cooled to room temperature in the furnace to obtain a sintered product (i.e., a roller alloy blank).

[0076] During SPS hot pressing sintering, the sintering temperature is 970℃; the specific heating method is: from room temperature to 400℃, the heating rate is 100℃ / min, from 400℃ to 700℃, the heating rate is 200℃ / min, from 700℃ to 970℃, the heating rate is 500℃ / min, and then kept at 970℃ for 1min; during SPS hot pressing sintering, the pressure is 20MPa, and the cold pressing molding and SPS sintering assembly are as follows: Figure 2shown.

[0077] D: Rough finishing: Based on the surface of the roller alloy blank obtained by SPS hot pressing and sintering, the hole and end face are machined according to the designed roller shape, size and accuracy, and then the roller alloy blank is trimmed on a grinding machine;

[0078] During the rough trimming process, the difference between the processed size and the actual size is 0.015 mm.

[0079] E: CVD diamond bar inlay: Manually implant the laser-cut CVD diamond bar (purchased from Hebei Pressman Diamond Technology Co., Ltd., size: 3mm*1mm*2mm) with paste silver-based solder (paste alloy solder) and insert it into the gap reserved in the outer ring of the roller alloy blank. At the same time, apply a layer of paste silver-based solder (paste alloy solder) on the surface of the roller alloy blank near the CVD diamond bar.

[0080] The paste-like silver-based solder is Ag72CuTi solder (Changsha Tianjiu Metal Materials Co., Ltd., -300 mesh), and the melting point of the Ag72CuTi solder is 780-810°C.

[0081] F: Vacuum drying: Use a vacuum drying oven to dry the paste Ag72CuTi solder coated on the roller alloy blank;

[0082] The drying temperature is 80° C., and the drying time is 1 h.

[0083] G: Gas shielded induction brazing: Assemble and fix the roller alloy blank inlaid with CVD diamond bars with the graphite jacket and upper and lower pressing molds, place them in a glove box, evacuate and fill with argon to form a protective atmosphere, use a medium frequency induction welding machine (SPG20K-35AB) and a contour heater to heat the CVD diamond bar area on the roller alloy blank, use an infrared thermometer to measure the temperature, slowly raise the temperature to 500℃ in the early stage, then increase the current to quickly raise the temperature of the area near the CVD diamond bar to 840℃, keep warm for 8s, complete the welding between the CVD diamond bar and the roller alloy blank, then cool to 650℃ for quenching treatment, and then perform tempering treatment, the tempering temperature is 280℃, the holding time is 2h, and the assembly is as follows during heating Figure 3 As shown; the equipment and components used in the gas shielded induction brazing process are conventional equipment in the field, and are not the inventive point of the present invention, so they are not described in detail.

[0084] H: Precision finishing: The roller alloy blank is precision machined according to the user's drawing standards, polished, and ultrasonically cleaned to remove the "hard skin" and debris on the substrate surface, so that it has precise geometric dimensions, shape and beautiful surface; the precision dimension is ≤0.005mm, and the CVD diamond roller product is obtained.

[0085] I: Inspection and packaging: The diamond rollers that have been precisely trimmed are strictly inspected to ensure their quality and grinding effect. They are then packaged after passing the inspection. The finished diamond rollers are Figure 4 As shown, the surface of the finished diamond roller is sprayed with anti-rust oil, wrapped with protective film, sealed and stored.

[0086] Example 2

[0087] Example 2 provides a method for manufacturing a high-strength and high-precision diamond tool, wherein the diamond tool is a diamond roller. The difference between Example 2 and Example 1 is that:

[0088] In step D, the difference between the processed size and the actual size is 0.02 mm.

[0089] In step E, the paste-like copper-based solder (paste-like alloy solder) is CuSn19Ti10 solder (Changsha Tianjiu Metal Materials Co., Ltd., -300 mesh), and the melting point of the CuSn19Ti10 solder is 850-870°C.

[0090] In step G, specifically, the roller alloy blank inlaid with CVD diamond bars is assembled and fixed with a graphite jacket and upper and lower pressing molds, placed in a glove box, vacuumed and filled with argon to form a protective atmosphere, and the CVD diamond bar area on the roller alloy blank is heated using a medium frequency induction welder (SPG20K-35AB) and a contour heater. The temperature is measured using an infrared thermometer, slowly heated to 450°C in the early stage, and then the current is increased to rapidly heat the temperature of the area near the CVD diamond bar to 900°C, and the temperature is kept for 5s to complete the welding between the CVD diamond bar and the roller alloy blank, and then cooled to 700°C for quenching treatment, and then tempered, with a tempering temperature of 300°C and a holding time of 2h.

[0091] Example 3

[0092] Example 3 provides a method for manufacturing a high-strength and high-precision diamond tool, wherein the diamond tool is a diamond roller. The difference between Example 3 and Example 1 is that:

[0093] In step B, powder is obtained according to a ratio of 70% by mass of W powder, 27.5% of Cu70Zn30 alloy powder (Guangzhou Metal Metallurgical Group Co., Ltd., 80-100 mesh), 0.5% of Cu30Fe70 powder (Shanghai Alloy Powder Science Research Center, 200-300 mesh), 0.5% of Cu30Ni70 powder (Hangzhuo Metal Materials, -300 mesh), 0.5% of Sn powder, and 1% of Mn-Cu damping alloy powder (Beijing Institute of High-tech Materials, 200-300 mesh);

[0094] The W powder has a particle size of 5-20 μm, the Cu70Zn30 powder has a particle size of 100-300 meshes, the Cu30Fe70 powder has a particle size of 150-300 meshes, the Cu30Ni70 powder has a particle size of 150-300 meshes, the Sn powder has a particle size of 200-400 meshes, and the Mn-Cu damping alloy powder has a particle size of 200-300 meshes.

[0095] In step C, during SPS hot pressing sintering, the sintering temperature is 930°C; the specific heating method is: the heating rate from room temperature to 400°C is 100°C / min, the heating rate from 400°C to 700°C is 200°C / min, and the heating rate from 700°C to 930°C is 500°C / min, and the holding time is 1 minute.

[0096] Performance Testing

[0097] The traditional diamond sintering roller preparation process (as shown below) Figure 5 ) (see literature: Wang Qingbin. Research on key technologies of precision diamond roller manufacturing process [D]. Zhengzhou University, 2023), as a control group, and the diamond sintered roller prepared in Example 1 were respectively subjected to CVD diamond strip arrangement, observation and measurement of the wear degree of CVD diamond strips of the finished roller, and testing of the bonding strength between CVD diamond strips and alloy blanks, Vickers hardness of the alloy blanks and service life of the finished roller.

[0098] Specifically, the arrangement of the CVD diamond strips and the degree of wear of the CVD diamond strips on the finished rollers were measured visually or under an optical microscope. The hardness test was conducted in accordance with the national standard GB / T 4340.1. The bonding strength between the CVD diamond strips and the alloy blank was tested using a small universal testing machine (referring to the national standard GB / T 11363-2008). Dressing tests were conducted on the same batch of grinding wheels using the same equipment model and the same process parameters. Diamond rollers prepared by the conventional sintering method and the SPS sintering-induction brazing composite process described in the present invention were tested and recorded. The comparative results are shown in Table 1 below.

[0099] Table 1 Comparison results

[0100] Test items Example 1 Traditional sintering process Diamond bar arrangement Similar spacing Different spacing Wear degree of finished roller diamond strip Low high Vickers hardness of finished roller alloy <![CDATA[370~402HV 0.5 ]]> <![CDATA[315~410HV 0.5 ]]> Diamond strip bond strength 110~130MPa 60~85MPa Finished roller service life 1.2 times 1x

[0101] Example 1 uses high-energy ball milling to process W and CuZn powders and adds active elements such as Fe, Ni, Mn, and Sn, combined with a spark plasma sintering process, to significantly improve the density and organizational uniformity of the alloy blank, and the hardness of the alloy blank is evenly distributed; compared with the CVD dressing roller prepared by the traditional sintering process in Example 1, the CVD diamond strips are evenly distributed and have good directional consistency; and the alloy blank is roughly trimmed first, and then the roller after brazing the CVD diamond is finely trimmed, with a fast dressing speed and high efficiency. At the same time, the wear of the CVD diamond strips is reduced during precision dressing. The CVD diamond strips and the alloy blank are chemically metallurgically bonded, with high bonding strength, which meets the requirements of higher-speed grinding and improves the service life of the finished roller.

[0102] The above embodiments are illustrative of the implementation methods of the present invention. The implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for manufacturing a high-strength and high-precision diamond tool, characterized in that: The method includes the following steps: (1) Design and processing According to the designed roller shape, size and precision, CVD diamond strip size and CVD diamond strip arrangement, the negative mold cavity is converted into the negative mold cavity, and high-purity graphite and steel are machined to obtain the graphite mold negative mold cavity and steel substrate; (2) Ball mill mixing Take the powder and ingredients, then put them into a mixer, seal them, ball mill them to obtain a mixture, dry them and set them aside; (3) SPS hot pressing sintering The mixed material is put into the negative mold cavity of the graphite mold, spread evenly, vibrated, and scraped flat, and then cold pressed. The steel substrate, the negative mold cavity, and the SPS sintering-upper pressing mold are then placed in the SPS sintering press and fixed. The press is vacuumed and filled with protective gas to form a protective atmosphere. The press is sintered under certain sintering temperature, sintering time, and sintering pressure conditions. After sintering, the press is cooled to room temperature to obtain a roller alloy blank. (4) Rough trimming Taking the roller alloy blank obtained by SPS hot pressing as the benchmark, the hole and end face benchmark are processed according to the designed roller shape, size and accuracy, and then the roller alloy blank is trimmed on the grinding machine; (5) CVD diamond bar inlay Dip the CVD diamond bar in a paste-like alloy solder and insert it into the gap reserved on the outer ring of the roller alloy blank. At the same time, apply a layer of paste-like alloy solder on the surface of the roller alloy blank near the CVD diamond bar and dry it. (6) Gas shielded induction brazing The roller alloy blank embedded with CVD diamond strips is assembled and fixed with a graphite jacket and upper and lower pressing molds. After vacuuming, an inert protective gas is filled to form a protective atmosphere. A medium-frequency induction welder and a contour heater are used to heat, quench, and temper the CVD diamond strip area on the roller alloy blank. (7) Precision finishing The roller alloy blank is subjected to precision machining, polishing and ultrasonic cleaning to obtain a CVD diamond roller product.

2. The method according to claim 1, wherein When taking powder in step (2), the powder is taken according to the ratio of 60-80% by mass of W powder, 15-38% by mass of Cu70Zn30 powder, 0.3-3% by mass of Fe powder or Cu30Fe70 powder, 0.1-2% by mass of Ni powder or Cu30Ni70 powder, 0.5-1% by mass of Sn powder, and 1-3% by mass of Mn-Cu damping alloy powder.

3. The method according to claim 2, wherein In step (2), the W powder has a particle size of 5-20 μm, the Cu70Zn30 powder has a particle size of 100-300 mesh, the Fe powder has a particle size of 5-10 μm, the Ni powder has a particle size of 5-10 μm, the Sn powder has a particle size of 200-400 mesh, the Mn-Cu damping alloy powder has a particle size of 200-300 mesh, the Cu30Fe70 powder has a particle size of 150-300 mesh, and the Cu30Ni70 powder has a particle size of 150-300 mesh.

4. The method according to claim 1, wherein In step (2), during ball milling, the ball-to-material ratio is 5-10:1, the ball mill speed is 150-300 r / min, and the ball milling time is 20-30 h.

5. The method according to claim 1, wherein In step (3), the cold pressing pressure is 70-100 MPa; the sintering temperature is 920-1000°C; the sintering time is 1-10 min; and the sintering pressure is 15-30 MPa.

6. The method according to claim 1, wherein In step (5), the paste alloy solder is a silver-based solder or a copper-based solder, and the melting point of the paste alloy solder is 780-870°C.

7. The method according to claim 6, wherein In step (5), the silver-based solder is Ag72CuTi solder, and the copper-based solder is CuSn19Ti10 solder. The melting point of the Ag72CuTi solder is 780-810°C, and the melting point of the CuSn19Ti10 solder is 850-870°C.

8. The method according to claim 1, wherein In step (6), the specific steps of heating, quenching, tempering and other treatments are as follows: initially heating to 400~500℃, then increasing the current to raise the temperature of the area near the CVD diamond bar to 840~900℃, holding the temperature for 5~10s to complete the welding between the CVD diamond bar and the roller alloy blank, then cooling to 650~710℃ for quenching treatment, and then tempering treatment, the tempering temperature is 250~350℃, and the holding time is 1~2h.

9. A high-strength and high-precision diamond tool manufactured by the method according to any one of claims 1 to 8, characterized in that: The diamond tool is a diamond roller.

10. Application of the high-strength and high-precision diamond tool according to claim 9 in the processing of high-precision products such as gears, bearings and guide rails.

Images