Film forming sintering method of diamond sintering grinding head

Abstract

The invention provides a film forming sintering method of a diamond sintered grinding head, which comprises the following steps: mixing diamond abrasive particles and metallic bond powder with a solvent with a film-forming property respectively to prepare slurry, and after the solution is volatilized, forming a film among the powder particles by the solvent. The slurry can be coated on a jig with a preset size, and a film with a corresponding size and shape can be obtained after the slurry is dried and volatilized. Powder particles are uniformly distributed in the slurry by adding a dispersing agent, performing powder surface treatment and performing ultrasonic vibration. And the diamond abrasive particle film and the metallic bond powder film are stacked in sequence, and the number of layers of the diamond abrasive particles is manually controlled. And fixing the particle film on a substrate, sintering in a furnace, melting and linking the metallic bond powder, and forming metallurgical bonding with the diamond abrasive particles. According to the method, the requirement for manufacturing the high-performance diamond product can be better met, and the manufactured diamond sintered product can easily meet the conditions of high-speed, high-efficiency and high-precision grinding.

Description

Technical Field

[0001] The invention belongs to the technical field of diamond product preparation, and in particular relates to a film forming and sintering method for a diamond sintered grinding head. Background Art

[0002] With the development of modern industry, such as aerospace, electronics, optics and other fields, the demand for processing high-hardness and brittle materials such as cemented carbide, ceramics, glass, and gems is increasing. These materials have the characteristics of high hardness and brittleness. It is difficult for traditional grinding wheels to grind them efficiently and accurately. Diamond grinding wheels have become an ideal choice for processing such materials due to their extremely high hardness and wear resistance. Among diamond grinding wheels, metal bond sintered grinding wheels are mostly used in high-hardness and high-load processing occasions due to their excellent holding strength. Metal bond sintered diamond grinding wheels are divided into two categories: multi-layer sintering and single-layer sintering. The common process of multi-layer sintered grinding wheels: mixing powder metallurgy metal powder with diamond abrasives, pressing and molding, and high-temperature sintering; after sintering, mechanical embedding force and metallurgical bonding force are generated between the metal powder and the diamond abrasives, and the two firmly hold the diamond abrasives. The common process of single-layer sintered (brazed) grinding wheel is as follows: diamond abrasive and metallurgical powder are spread on the substrate as evenly as possible, and the abrasive and metallurgical powder are adhered to the surface of the substrate by spraying adhesive, and then multiple layers are spread to ensure sufficient sintering layer thickness; after spreading, the wheel is put into the furnace for sintering. The sintering is generally solid-phase / liquid-phase mixed sintering, so that the metallurgical powder is liquefied and connected into a whole, and metallurgical bonding is generated with the diamond abrasive to form a solid grinding layer.

[0003] However, the existing processing technology has the following technical problems: the molding and hot pressing molds and jigs are greatly restricted by the size of the finished grinding wheel, and different sizes require different molds and jigs; when dealing with complex external dimensions, only molds and jigs with relatively regular sizes can be used, which leads to more removal allowances, increases the cost of raw materials and the cost of subsequent shaping; due to the limitations of the manufacturing process, the distribution of abrasive grains on the surface of the grinding wheel is random, and the geometric shape, distribution and cutting edge height of each abrasive grain are inconsistent, resulting in only a few higher cutting edges being able to cut the workpiece during grinding, limiting the further improvement of grinding quality and grinding efficiency. Summary of the invention

[0004] The purpose of the present invention is to provide a film forming sintering method for a diamond sintered grinding head, which can better meet the requirements of manufacturing high-performance diamond products and make it easier for the obtained diamond sintered products to achieve high-speed, high-efficiency and high-precision grinding conditions. The method has the characteristics of high economic benefits, clean and energy-saving, and simple process.

[0005] The film forming sintering method of a diamond sintered grinding head described in the present invention comprises the following steps:

[0006] S1: slowly add highly substituted hydroxypropyl cellulose to a proper amount of a mixed solvent of isopropanol and ethanol, wherein the volume ratio of isopropanol to ethanol is 1:2; stir while adding to fully dissolve the hydroxypropyl cellulose to obtain a basic solvent A;

[0007] S2: Based on the basic solvent A, the proportion of highly substituted hydroxypropyl cellulose is adjusted to obtain a basic solvent B;

[0008] S3: Based on the base solvent A, oleic acid is added in an amount of 0.5% of the mass of the metal binder powder to obtain a base solvent C;

[0009] S4: filtering the base solvent B and the base solvent C;

[0010] S5: mixing diamond with a base solvent B, wherein the volume proportion of diamond is 15% to 30%, and after mixing, using ultrasonic stirring to obtain a mixed solution A;

[0011] S6: mixing the metal binder powder with the base solvent C, wherein the mass fraction of the metal binder powder is 30% to 50%, to obtain a mixed solution B;

[0012] S7: Based on the mixed solution A or the mixed solution B, a planar film is formed by a spin coating process, or a contoured film is formed by a casting process;

[0013] S8: After taking the film, dry film stacking and sintering are performed, and finally shaping is performed.

[0014] Wherein, the planar film is formed by spin coating process based on mixed solution A or mixed solution B, comprising:

[0015] Dropping the mixed solution A or the mixed solution B onto a substrate that is rotating at a high speed, wherein the rotation speed is set at 500-1500 rpm;

[0016] The mixed solution A or the mixed solution B is evenly spread on the surface of the substrate and forms a thin film after volatilization;

[0017] Perform spin coating for 30-60 seconds, remove the substrate with the thin film from the spin coating equipment, place it in a heated and ventilated environment to dry for 8-12 hours, and remove the flat film.

[0018] The method of removing the substrate with the thin film from the spin coating device further comprises:

[0019] The whole flat film is placed on a plastic plate with through holes of different sizes reserved on the plastic plate, which is fixed with racks on all sides. Circular punches of different sizes are used to punch the reserved holes on the plastic plate to obtain circular flat films of different sizes, wherein diamond abrasive grains or metal binder particles are distributed on the flat film.

[0020] After the planar film is removed, the method further includes: planar film stacking; specifically:

[0021] Take a flat film with diamond abrasive grains and metal binder particles, place the grinding head base in a mold, press the flat film into the mold, and use a die punch to compact the stacked multi-layer flat film; after compaction, spray a small amount of alcohol on the outer surface of the stacked blank to moisten it;

[0022] The order is that the bottom layer is 3 metal powder films, the middle layer is 2 diamond films and 2 metal powder films overlapped to a specified number of layers, and finally covered with 2 layers of metal powder films.

[0023] The method of forming a contoured film based on the mixed solution A or the mixed solution B by using a casting process comprises:

[0024] Make a die head with contoured dimensions;

[0025] The die head rotates continuously through the bottom rotating mechanism, and the speed does not exceed 120rpm;

[0026] The mixed liquid is dripped onto the center of the top of the die through the flow control nozzle. At the same time, the die keeps rotating. According to the different sizes of the die profiling, the mixed liquid flow is controlled until the profiling part of the die is completely covered by the mixed liquid. The die keeps rotating for more than 15 minutes to allow the mixed liquid to flow and spread fully.

[0027] The excess mixed liquid is scraped off by a high-precision scraper, leaving only a mixed liquid layer with the thickness of the gap between the high-precision scraper and the die head;

[0028] Turn on the lighting heating lamp to start heating. There should be at least 4 heating lamps evenly distributed along the rotating axis 360°. The temperature of the die head profiling area should be controlled at 50° to 60°.

[0029] After heating is completed, a contoured film inlaid with diamond particles or metal binder particles is formed;

[0030] Turn off the heat lamp, apply vibration to the die, and remove the contoured film.

[0031] After removing the contour film, it also includes: dry film stacking; specifically:

[0032] Take a flat film with diamond abrasive grains and metal binder particles, place the grinding head base in a mold, first spray a mixture of isopropyl alcohol and ethanol on the stacking surface of the grinding head base to wet it, spread 3 metal binder contour films on the base surface, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it, spread 2 diamond contour films on the above films in turn, and spray a mixture of isopropyl alcohol and ethanol to wet it; and spread 2 metal binder contour films on the aforementioned diamond films, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it again; lay 2 metal binder films on the last layer of diamond film; after all the films are laid, use a contour punch to lightly press on the stacked blank; the film stacked blank adheres to the grinding head base and is taken out of the mold as a whole.

[0033] The sintering comprises:

[0034] The sintering is solid phase or liquid phase mixed sintering; the maximum temperature is higher than the liquidus temperature of the metal binder powder, and the excess temperature is not higher than 50 degrees;

[0035] In the sintering furnace, the grinding head must be placed vertically.

[0036] Based on the same inventive concept, the present application also proposes a diamond sintered grinding head, which is manufactured by using the film forming and sintering method of the above-mentioned diamond sintered grinding head.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] Diamond abrasive grains are embedded in the film, and through dispersant and ultrasonic stirring treatment, a relatively uniform distribution in the plane direction can be achieved; through orderly stacking of the film, a relatively regular distribution of abrasive grains can be achieved in the vertical direction. The regular distribution of diamond abrasive grains can improve the life of the grinding head and the surface quality of the processed surface.

[0039] By regularly stacking the film, the number of layers of diamond abrasives can be controlled more accurately, thereby achieving a certain degree of precise control over the life of the grinding head. This is very beneficial for workshop management, production scheduling and tool warehouse management under large-scale, automated processing conditions.

[0040] Compared with the powder pressure forming process, the stacked film forming process greatly reduces the requirements of the process on the mold and fixture, especially the contoured stacked film forming process. The size and shape of the contoured film is determined by the size of the die head, and it is very convenient to manufacture films of various sizes and shapes. Compared with the traditional powder forming process, not only the mold and fixture cost is reduced, but also the reserved amount and the amount of post-process removal are reduced, which brings greater benefits to the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1This is a flow chart of a film forming sintering method for a diamond sintered grinding head in this embodiment.

[0042] Figure 2 It is a schematic diagram of the casting process in this embodiment.

[0043] Figure 3 Schematic diagram of the stacking of planar films in this embodiment.

[0044] In the figure: 1. mold; 2. grinding head base; 3. metal binder film; 4. flat diamond film; 5. scraper; 6. gap layer; 7. bottom rotating mechanism. DETAILED DESCRIPTION

[0045] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0046] Embodiment 1:

[0047] like Figure 1 As shown, a film forming and sintering method for a diamond sintered grinding head, the manufacturing process of the method is: powder pretreatment - preparation of suspension solvent - mixing - film forming and film taking - dry film stacking - sintering - shaping.

[0048] (1) Powder pretreatment: Diamond abrasive and metal binder powder are cleaned and pre-milled to improve the adhesion between diamond abrasive and metal binder to ensure their good bonding in subsequent processing. It helps to remove impurities on the powder surface, improve the dispersion of powder, and perform necessary treatment on the particle surface to improve the subsequent process effect.

[0049] The cleaning ball milling pretreatment process of diamond abrasive grains and metal binder powder mainly includes the steps of ball milling, cleaning, drying, screening and dispersion, including:

[0050] Ratio of powder and solvent: According to the specific amount of diamond abrasive and metal binder powder, add an appropriate amount of solvent (such as deionized water, ethanol, etc.) to prevent the powder from agglomerating during the ball milling process and help remove surface impurities. Usually the ratio of diamond abrasive and metal powder is adjusted according to needs, generally the amount of diamond abrasive is less and the amount of metal powder is more.

[0051] Ball milling process: put diamond abrasive, metal binder powder and solvent into the ball mill, and start the ball mill to mix. The ball milling time usually ranges from a few hours to more than ten hours, and the specific time is adjusted according to the type of powder and the requirements of the treatment effect. During the ball milling process, the powder will interact with each other through the impact and friction of the ball milling medium, and the surface impurities will be gradually removed. At the same time, some mechanical damage may occur on the powder surface, which increases the contact area between the diamond abrasive and the metal binder, which is conducive to enhancing the bonding.

[0052] Cleaning and drying: After ball milling, take out the mixed powder and wash it with deionized water or other suitable solvent to remove residual solvent, impurities or powder generated during ball milling. The cleaned powder needs to be dried, usually by vacuum drying or oven drying, to ensure that the powder is completely dry and free of moisture.

[0053] Screening and dispersion treatment: The dried powder needs to be screened to remove larger particles or unqualified powder to ensure uniform particle size distribution of the powder. If the powder is agglomerated, it can be further treated by ultrasonic treatment or other dispersion techniques to improve the dispersibility of the powder.

[0054] Subsequent processing: After completing the above steps, the pre-treated powder of diamond abrasive and metal binder can be used in subsequent synthesis processes, such as pressing and molding of diamond grinding wheels.

[0055] (2) Slowly add highly substituted hydroxypropyl cellulose to a proper amount of a mixed solvent of isopropyl alcohol and ethanol, wherein the volume ratio of isopropyl alcohol to ethanol is 1:2; stir while adding to fully dissolve it, and obtain basic solvent A. Preliminary stirring can be performed at room temperature, and then heating can be performed appropriately as needed to accelerate dissolution, but the temperature should not be too high to avoid affecting the properties of cellulose. For example, stirring can be performed in a water bath at 40-60°C until the solution becomes clear and transparent to form a uniform glue solution. The purpose of heating is to accelerate the dissolution process, but it should be noted that the temperature should not be too high (generally not exceeding 60°C), because too high a temperature may affect the solubility and structure of hydroxypropyl cellulose, and even lead to a decrease in performance. The dissolved solution may contain some bubbles, which will affect the quality of the film and cause pores or defects in the film. Therefore, the solution needs to be degassed. The solution can be left to stand for a period of time to allow the bubbles to escape naturally, or decompression degassing and other methods can be used to accelerate the removal of bubbles.

[0056] (3) Based on the base solvent A, the proportion of high-substituted hydroxypropyl cellulose is adjusted to obtain base solvent B. Among them, controlling the proportion of high-substituted hydroxypropyl cellulose to adjust the thickness of the dried film preferably includes: for diamonds around 600#, the proportion is 5%; for diamonds around 400#, the proportion is 7.5%; for diamonds around 200#, the proportion is 10%; by adding polyvinyl pyrrolidone, the addition amount is about 1%-3% of the mass of diamond; and polyethylene glycol, the addition amount is 0.5%-1.5% of the mass of diamond, to improve the dispersibility of diamond in the solvent

[0057] (4) Based on the base solvent A, oleic acid is added in an amount of 0.5% by weight of the metal binder powder to obtain a base solvent C. Preferably, oleic acid is added in an amount of about 0.5% by weight of the metal binder powder to improve the dispersibility of the metal binder powder in the solvent.

[0058] (5) Filter the base solvent B and the base solvent C. Preferably, filter paper with a mesh size of about 1 μm is used for filtration to remove particles that are not completely dissolved or agglomerated in the solvent.

[0059] (6) Diamond is mixed with a base solvent B, wherein the volume proportion of diamond is 15% to 30%, and after mixing, ultrasonic stirring is performed to obtain a mixed solution A. The ultrasonic time is more than 30 minutes, and the stirring blade speed is 120 rpm.

[0060] (7) Mixing the metal binder powder with the base solvent C, wherein the mass fraction of the metal binder powder is 30% to 50%, to obtain a mixed solution B. The ultrasonic time is more than 30 minutes, and the stirring blade speed is 120 rpm.

[0061] (8) Based on the mixed solution A or the mixed solution B, a planar film is formed by a spin coating process, or a contoured film is formed by a casting process. Specifically, the film forming process can be divided into a spin coating process and a casting process according to the actual size and shape requirements.

[0062] Spin coating process: used to form a flat film, which can be used as a standard film for laminated molding. Drop the mixed liquid A or B on a high-speed rotating substrate, such as a glass sheet. The rotation speed of the substrate has a great influence on the thickness of the film, and the rotation speed is generally between 500-1500 rpm. If a thicker film is to be prepared, the rotation speed can be controlled at 500-1000 rpm; if a thinner film is to be prepared, the rotation speed can be increased to 1000-1500 rpm. The mixed liquid is evenly spread on the surface of the substrate under the action of centrifugal force, and the solvent evaporates quickly to form a film. The spin coating process generally lasts 30-60 seconds, after which the substrate with the film is removed from the spin coating equipment and placed in a heated and ventilated environment for further drying, and the drying time is about 8-12 hours.

[0063] Flat film removal: Place the entire flat film on a plastic plate with holes of different sizes reserved on the plate, and fix it with a rack around it. Use circular punches of different sizes to punch the reserved holes on the plastic plate to obtain circular films of different sizes. Diamond abrasive particles or metal binder particles are distributed on the film.

[0064] like Figure 2 As shown, the casting process is used for the production of contoured films. First, make a die with contoured dimensions, as shown in Figure 1. The die can be made of stainless steel, and the surface is required to have no obvious knife marks or grooves, and Ra<0.2. The die rotates continuously through the bottom rotating mechanism (7 in the figure), and the speed does not exceed 120rpm. Through the flow control nozzle (1 in the figure), the mixed liquid drop (4 in the figure) is placed at the center of the top of the die, and the liquid volume can be slightly more. At the same time, the die keeps rotating. According to the different sizes of the die contouring size, the flow rate of the mixed liquid is controlled. Generally, it is required to ensure that the contoured part of the die is completely covered by the mixed liquid casting. After reaching the above state, the die keeps rotating for more than 15 minutes to allow the mixed liquid to flow and flatten fully.

[0065] Through the contoured high-precision scraper (5 in the figure), close to the die head, using a lathe-like processing method, the excess mixed liquid is scraped off, leaving only a mixed liquid layer with a thickness of the gap between the high-precision scraper and the die head (6 in the figure).

[0066] Turn on the lighting heating lamp (2 in the figure) to start heating. There should be at least 4 heating lamps evenly distributed along the rotating axis 360°. The temperature of the die profiling area is controlled at 50° to 60°; the heating time is related to the die size. A die with a diameter of 6mm is heated for about 4 hours, and a die with a diameter of 20mm is heated for about 8 hours.

[0067] Removal of contour film: After heating, the mixed liquid has formed a dry film inlaid with diamond particles or metal binder particles; turn off the heating lamp, apply vibration to the die head, and the dry film can be removed more conveniently.

[0068] (9) After the film is taken, dry film stacking and sintering are performed, and finally shaping is performed.

[0069] like Figure 3 As shown, the dry film stack:

[0070] Stacking of planar films (multiple layers): Take a planar diamond film (4 in the figure) and a metal binder film (3 in the figure), and clean the stacking surface of the grinding head base (2 in the figure) by sandblasting. Place the grinding head base in the mold (1 in the figure) and press the planar film into the mold. First, lay 3 metal binder films (3 in the figure), then 2 diamond films (4 in the figure), then 2 metal binder films, then 2 diamond films, and so on. Generally, for a single-layer sintered grinding head, 4 to 6 layers of diamond films can be stacked; for a multi-layer sintered grinding head, more than 10 layers of diamond films can be stacked. Lay 2 metal binder films on the last layer of diamond film. Use a die punch to compact the stacked multi-layer planar film. The pressure is based on the forming and upright strength of the film stacking blank, which generally does not exceed 100MPa. After compaction, spray a small amount of alcohol on the outer surface of the stacking blank to moisten it. After completion, remove the grinding head base and the film stacking blank from the mold as a whole.

[0071] Contour film stacking (fewer layers): Take contour diamond film and metal binder film, and clean the stacking surface of the grinding head substrate by sandblasting. Place the grinding head substrate in the mold, first spray a mixture of isopropyl alcohol and ethanol on the stacking surface of the grinding head substrate to wet it, then spread 3 metal binder contour films on the substrate surface, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it. High-pressure gas can be used to blow it flat during the spreading process; then spread 2 diamond contour films on the above films, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it again; then spread 2 metal binder contour films on the above diamond films, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it again; and so on. Contour film stacking process is generally used in the manufacture of single (few) layer sintered grinding heads. The stacking layers of diamond films generally do not exceed 3 layers, and 2 metal binder films are laid on the last layer of diamond film. After all the film is laid, use the contour die to press lightly on the stacked blank, and the pressure generally does not exceed 30MPa. After completion, the film stacked blank adheres to the grinding head base and is removed from the mold as a whole.

[0072] sintering:

[0073] The sintering process is a pressureless sintering process, and the equipment is a vacuum brazing furnace, which is similar to the common processes in the current industry and will not be described in detail. There are several requirements to note:

[0074] A. It is necessary to keep the temperature at which the film decomposes and evaporates for more than 30 minutes to ensure that the film components are decomposed and taken out before continuing to heat up;

[0075] B. The sintering is solid phase / liquid phase mixed sintering, and the maximum temperature should be higher than the liquidus temperature of the metal binder powder, and the excess temperature should not exceed 50 degrees; considering the thermal stability of diamond, it is not recommended to select metal binder materials with liquidus temperature exceeding 900 degrees to match this invention process;

[0076] C. In the sintering furnace, the grinding head must be placed vertically, and the vibration of the equipment must be suppressed as much as possible through the clamping fixture to prevent the collapse of the film stack.

[0077] Repair type:

[0078] Use electric spark dressing equipment or grinding wheel dressing equipment to shape the sintered grinding head. This is a common process in the industry and will not be described in detail.

[0079] In order to further illustrate the effectiveness of the film forming sintering method of the diamond sintered grinding head described in the present invention, the application cases are further given as follows:

[0080] Manufacturing process of sintered grinding head for glass edge grinding.

[0081] 1) Use bronze-based binder, copper 70%, silver 20%, tin 8%, other 2%. Liquidus is 870°, particle size is -325 mesh, ball milled for 1H, loose without agglomeration; diamond is MBD10 type 400 mesh diamond, diamond abrasive has been cleaned; base material is 45# steel, structure is divided into handle and blade, handle diameter is 10mm, blade diameter is 8mm, handle length is 60mm;

[0082] 2) Prepare basic solvent A: After isopropanol and ethanol are mixed in a volume ratio of 1:2, heat to 60°, and add 7% of high-substituted hydroxypropyl cellulose powder by mass. The cellulose powder needs to be ball-milled and dried, and there should be no moisture and lumps. After adding the cellulose powder, use a stirring paddle with a diameter not exceeding 75% of the diameter of the measuring cup to stir the solvent at a speed of 240rpm for 60min, and apply ultrasound at the same time. After visually inspecting that the solvent is clear and uniform, add polyvinyl pyrrolidone at a preset diamond mass of 1% to improve the dispersibility of the diamond abrasive after the later addition. This is solvent ①. Similarly, in a 1:2 mixture of isopropanol and ethanol, a high-substituted hydroxypropyl cellulose powder with a mass fraction of 4.5% is added. After the same stirring process, the solvent is added with oleic acid at a preset metal binder powder mass of 0.5% to improve the dispersibility after the metal binder powder is added later. This is solvent ②.

[0083] Solvent ① and solvent ② were filtered using 1 μm filter paper to remove hidden agglomerates.

[0084] 3) Mixing: Take MBD10-400# diamond with a volume fraction of 25%, add it to solvent ①, first use the above-mentioned ultrasonic plus stirring paddle process, pre-stir for 60 minutes, then send it to vacuum degassing and stirring for 30 minutes to obtain a mixed solution ①.

[0085] Take 40% metal binder powder by mass, add it into solvent ②, first use the aforementioned ultrasonic plus stirring paddle process, pre-stir for 60 minutes, then send it to vacuum degassing and stirring for 30 minutes to obtain a mixed solution ②.

[0086] 4) Plane film formation: Mixed liquid ① and mixed liquid ② are dripped on the center of two glass flat turntables through the flow control nozzle. The amount of liquid should be enough to completely cover the entire plane. Excessive amount is allowed. Mixed liquid ① is spun at a speed of 1000rpm for 60s to form a liquid film with a thickness of about 0.06-0.75mm; mixed liquid ② is spun at a speed of 1500rpm for 60s to form a liquid film with a thickness of about 0.04-0.06mm. Then remove the two glass platforms and place them in a blast drying oven with the temperature set to 65°. After drying for 8 hours, the liquid film dries into a thin film. Because of the wrinkles and warping, it can be easily removed from the glass platform.

[0087] 5) Mold taking: Spread the film on the bakelite board and compact it with a pressing block on all sides. The bakelite board is preset with a 9.5mm diameter through hole evenly distributed in a dot matrix. There is a punch head mechanism above the bakelite board. The punch head is annular, with an outer diameter of 9mm and a wall thickness of 0.3mm. The position is coaxial with the bakelite through hole. Operate the punch mechanism, and the punch head quickly punches down to process the film laid on the bakelite board into a circular film with a diameter of about 8.4mm.

[0088] 6) Molding: After cleaning, sandblasting and rust removal, place the 45# steel substrate in the mold. Then send the circular film into the mold and cover the end face of the substrate. The order is 3 metal powder films, 2 diamond films, 2 metal powder films, and 2 diamond films. The diamond layer is designed to be 10 layers, and finally 2 layers of metal powder film need to be covered. During this period, the stacked film can be flattened by air blowing. After the stacking is completed, use a punch to press down to compact the multi-layer film. After compaction, the substrate is pushed out, and the film stack is in a blank shape and adheres to the end of the substrate.

[0089] 7) Sintering: Spray a little alcohol on the molded blank to moisten it. Use 150ml spray bottle and press 2 pumps. Dry it for 5 minutes and then send it into the vacuum furnace for sintering. The sintering process is not described in detail. It requires additional attention: keep it at 400° for 20 minutes, keep it at 550° for 45 minutes, and then directly reach the highest temperature of 920°.

[0090] 8) Shape repair: After sintering, use electric spark or mechanical shape repair, which will not be described in detail.

[0091] Embodiment 2:

[0092] The present application also proposes a diamond sintered grinding head, which is made by the above-mentioned film forming and sintering method of a diamond sintered grinding head. By adopting the above-mentioned film forming and sintering method to prepare a diamond sintered grinding head, the quality and performance of the grinding head can be effectively improved, especially in terms of hardness and wear resistance. This method can ensure that the diamond particles are firmly bonded to the substrate, while ensuring the uniformity of the film layer, providing an efficient and stable tool for subsequent grinding, cutting and other operations.

[0093] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A film forming sintering method for a diamond sintered grinding head, characterized in that: The following steps are involved: S1: slowly add highly substituted hydroxypropyl cellulose to a proper amount of a mixed solvent of isopropanol and ethanol, wherein the volume ratio of isopropanol to ethanol is 1:2; stir while adding to fully dissolve the hydroxypropyl cellulose to obtain a basic solvent A; S2: Based on the base solvent A, the proportion of highly substituted hydroxypropyl cellulose is adjusted to obtain a base solvent B; S3: Based on the base solvent A, oleic acid is added in an amount of 0.5% of the mass of the metal binder powder to obtain a base solvent C; S4: filtering the base solvent B and the base solvent C; S5: mixing diamond with a base solvent B, wherein the volume proportion of diamond is 15% to 30%, and after mixing, using ultrasonic stirring to obtain a mixed solution A; S6: mixing the metal binder powder with the base solvent C, wherein the mass fraction of the metal binder powder is 30% to 50%, to obtain a mixed solution B; S7: Based on the mixed solution A or the mixed solution B, a planar film is formed by a spin coating process, or a contoured film is formed by a casting process; S8: After taking the film, dry film stacking and sintering are performed, and finally shaping is performed.

2. The film forming sintering method of a diamond sintered grinding head according to claim 1, characterized in that: The method of forming a planar film based on the mixed solution A or the mixed solution B by a spin coating process comprises: Dropping the mixed solution A or the mixed solution B onto a substrate that is rotating at a high speed, wherein the rotation speed is set at 500-1500 rpm; The mixed solution A or mixed solution B is evenly spread on the surface of the substrate and forms a thin film after volatilization; the spin coating is performed for 30-60 seconds, the substrate with the thin film is removed from the spin coating device, and placed in a heated and ventilated environment for drying for 8-12 hours, and the flat film is removed.

3. The film forming sintering method of a diamond sintered grinding head according to claim 2, characterized in that: The method of removing the substrate with the thin film from the spin coating device further comprises: The whole flat film is placed on a plastic plate with through holes of different sizes reserved on the plastic plate, which is fixed with racks on all sides. Circular punches of different sizes are used to punch the reserved holes on the plastic plate to obtain circular flat films of different sizes, wherein diamond abrasive grains or metal binder particles are distributed on the flat film.

4. The film forming sintering method of a diamond sintered grinding head according to claim 3, characterized in that: After the planar film is removed, the method further includes: planar film stacking; specifically: Take a flat film with diamond abrasive grains and metal binder particles, place the grinding head base in a mold, press the flat film into the mold, and use a die punch to compact the stacked multi-layer flat film; after compaction, spray a small amount of alcohol on the outer surface of the stacked blank to moisten it; The order is that the bottom layer is 3 metal powder films, the middle layer is 2 diamond films and 2 metal powder films overlapped to a specified number of layers, and finally covered with 2 layers of metal powder films.

5. The film forming sintering method of a diamond sintered grinding head according to claim 1, characterized in that: The method of forming a contoured film based on the mixed solution A or the mixed solution B by using a casting process comprises: Make a die head with contoured dimensions; The die head rotates continuously through the bottom rotating mechanism, and the speed does not exceed 120rpm; the mixed liquid is dripped on the center of the top of the die head through the flow control nozzle, and the die head keeps rotating. According to the different sizes of the die head profiling, the flow rate of the mixed liquid is controlled until the profiling part of the die head is completely covered by the mixed liquid. The die head keeps rotating for more than 15 minutes to allow the mixed liquid to flow and spread fully.

6. The film forming sintering method of a diamond sintered grinding head according to claim 5, characterized in that: The method of preparing the contoured film by using a casting process based on the mixed solution A or the mixed solution B also includes: The excess mixed liquid is scraped off by a contoured high-precision scraper, leaving only a mixed liquid layer with the thickness of the gap between the high-precision scraper and the die head.

7. The film forming sintering method of a diamond sintered grinding head according to claim 6, characterized in that: The method of preparing the contoured film by using a casting process based on the mixed solution A or the mixed solution B also includes: Turn on the lighting heating lamp to start heating. There should be at least 4 heating lamps evenly distributed along the rotating axis 360°. The temperature of the die head profiling area should be controlled at 50° to 60°. After heating is completed, a contoured film inlaid with diamond particles or metal binder particles is formed; Turn off the heat lamp, apply vibration to the die, and remove the contoured film.

8. The film forming sintering method of a diamond sintered grinding head according to claim 7, characterized in that: After removing the contour film, it also includes: dry film stacking; specifically: Take a flat film with diamond abrasive grains and metal binder particles, place the grinding head base in a mold, first spray a mixture of isopropyl alcohol and ethanol on the stacking surface of the grinding head base to wet it, spread 3 metal binder contour films on the base surface, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it, spread 2 diamond contour films on the above films in turn, and spray a mixture of isopropyl alcohol and ethanol to wet it; and spread 2 metal binder contour films on the aforementioned diamond films, and lightly spray a mixture of isopropyl alcohol and ethanol to wet it again; lay 2 metal binder films on the last layer of diamond film; after all the films are laid, use a contour punch to lightly press on the stacked blank; the film stacked blank adheres to the grinding head base and is taken out of the mold as a whole.

9. The film forming sintering method of a diamond sintered grinding head according to claim 1, characterized in that: The sintering comprises: The sintering is solid phase or liquid phase mixed sintering; the highest temperature is higher than the liquidus temperature of the metal binder powder, and the excess temperature is not higher than 50 degrees; the grinding head is placed vertically in the sintering furnace.

10. A diamond sintered grinding head, characterized in that: The diamond sintered grinding head is manufactured by using the film forming and sintering method for a diamond sintered grinding head as described in any one of claims 1-9.

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