Preparation method of multi-layer brazed diamond tool based on injection molding

Abstract

The invention provides a preparation method of a multi-layer brazed diamond tool based on injection molding, which comprises the following steps: preparing an injection molding feed, preparing a diamond working layer matrix unit, splicing and assembling a large-size diamond working layer matrix, and putting diamonds and a brazing material; degreasing and sintering or brazing treatment; the obtained diamond multilayer brazing tool is subjected to post-processing to meet the size precision, and the edging meets the use requirement. The method is suitable for manufacturing multiple diamond tools such as multi-layer diamond gravers, trepanning cutters, milling cutters, drill bits, wire saws and beads. The arrangement mode and the distribution density of the diamond abrasive particles can be accurately controlled, and meanwhile the tool performance and the machining efficiency are improved. The manufactured tool has the following advantages that the thickness of the diamond abrasive particle layer can be adjusted, the cutting edge is sharp, the edge exposure height is larger than 50%, the chip containing space is obviously increased, blocking is not prone to occurring, and therefore the abrasion resistance and the cutting efficiency of the diamond tool can be fully exerted.

Description

Technical Field

[0001] This invention belongs to the field of superhard material tool manufacturing and hard and brittle material processing technology, and specifically relates to a method for preparing multilayer brazed diamond tools based on injection molding. Background Technology

[0002] Due to the high interfacial energy and poor interfacial wettability between diamond and metal materials, tools prepared by hot pressing and electroplating only have mechanical bonding and physical adhesion between the metal bond and diamond, resulting in low diamond holding strength and limited tool machining accuracy and service life. Brazed diamond tools, on the other hand, achieve a strong metallurgical bond between diamond, brazing alloy, and the matrix. This not only increases diamond holding strength and cutting edge height but also improves self-sharpening and cutting performance, making it the mainstream method for high-speed, high-load cutting operations.

[0003] Currently, diamond tools manufactured using the brazing method are mainly single-layer brazed diamond tools. While single-layer brazed diamond tools offer advantages such as high hardness, high efficiency, and high diamond tipping, they also suffer from short lifespan and high operating costs. Multi-layer brazed diamond tools offer significant advantages over single-layer tools. First, the diamond particle distribution is more uniform, and the multi-layer structure effectively improves tool durability and reduces costs. The multi-layer structure enhances the bonding force between the diamond particles and the matrix, reducing the risk of particle detachment and thus extending the tool's lifespan.

[0004] Current methods for preparing multilayer brazed diamond tools have several drawbacks. One method involves machining grooves into the substrate, applying diamond and brazing filler to these grooves, and then brazing. This method is costly, and the substrate often has high toughness, which doesn't necessarily improve the toughness of the diamond. Some literature reports adding diamond and brazing filler to a steel mesh and then stacking them to create a multilayer brazed diamond structure. However, this method is inconvenient to manufacture and not conducive to large-scale production. Another method involves coating brazing filler metal with diamond to prepare brazed diamond particles. These particles are then added to a metal binder and sintered to form a diamond product, considered a multilayer brazed diamond tool. Tools prepared using this method show a significant improvement in diamond holding power. However, there are still differences in sharpness and edge height, and preparing brazed diamond particles is not easy. The method for preparing multilayer brazed diamond as described in Chinese patent (CN108789189A) suffers from the inability to precisely control the multilayer structure, and the brazing is brittle, especially with BNi-2 nickel-based brazing, where the outer diamond layer easily detaches. Generally, this method only produces a maximum of two layers. Furthermore, in the multilayer brazed diamond tool prepared by 3D printing mentioned in Chinese patent CN113560564A, everything except the diamond is brazed. If made into a very dense tool, the cutting edge is poor; if made porous, the strength is insufficient. The method used in this patent, however, employs injection molding to prepare a recessed structural unit using two materials. One material is brazed, which is placed in the recessed structure along with the diamond, providing excellent diamond retention. The other material is a matrix material that not only provides excellent fixation for the brazing filler portion but also wears faster than the brazing filler portion during diamond tool operation, providing excellent cutting edge performance. Metal powder injection molding technology mixes metal powder and resin, similar to the production of plastic products, allowing for the one-time production of complex-shaped metal parts. Metal powder injection molding technology can perform precision machining on materials that cannot be processed by traditional machining, such as ceramics, cemented carbide, and magnetic materials. Its mechanical properties are superior to castings and close to forgings. It has high precision, smooth surface, generally no need for subsequent processing, and high product performance consistency. It is suitable for mass production of parts that are small in size, have complex structures, large batches, and high precision requirements.

[0005] Leveraging the ability of injection molding to fabricate complex shapes, diamond working layer matrix units are prepared. These matrix units have numerous recessed structures. Diamond brazing filler metal or a diamond-molded composite is applied to or embedded into these recessed structures. The number of diamond layers to be brazed is determined by the depth of the recessed structures and the diameter of the diamond, allowing for the fabrication of multi-layer diamond brazing tools. This multi-layered diamond brazing tool ensures that the diamond brazing is perpendicular to the workpiece, improving efficiency.

[0006] For diamond tools with too many inline recesses, large size, and difficult injection molding, the smallest injectable matrix unit of the diamond working layer matrix can be injection molded first, hereinafter referred to as the diamond working layer matrix unit. Then, the diamond working layer matrix units can be combined or spliced ​​into diamond tools with specific required shapes. In this way, multi-layer brazed diamond tools with complex shapes and high precision can be prepared. Summary of the Invention

[0007] This invention provides a method for preparing multilayer brazed diamond tools based on injection molding, overcoming the short lifespan of existing brazed diamond tools. It ensures consistent abrasive grain exposure height, regular abrasive grain arrangement, high cutting edge extension, high bonding strength between the binder and diamond, controllable diamond layer number, and perpendicularity of the diamond alignment to the machined surface.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for fabricating a multilayer brazed diamond tool based on injection molding includes the following steps: 1) Preparation of injection molding feedstock: Mix metal powder, inorganic material powder, polymer binder and solvent in proportion, and then knead at 150-200℃ for 35 minutes to 4 hours. Then crush and screen to obtain feedstock that meets the requirements of injection molding process. 2) Preparation of diamond working layer matrix unit: The feed prepared in step 1) is used to prepare diamond working layer matrix unit by injection molding technology. The surface of the matrix unit has concave and convex structures with specific shapes and depths, which facilitates the subsequent filling and fixing of materials into the concave structures.

[0009] 3) Assembling large-size diamond working layer substrates: For diamond tools with large dimensions or complex shapes, small-size substrate units can be prepared first using injection molding technology. Then, these small substrate units are spliced ​​and assembled according to a specific design to form a large-size diamond working layer substrate that meets specific application requirements.

[0010] 4) Place diamond and brazing filler; prepare brazing paste by uniformly mixing superhard materials (such as diamond particles), brazing filler, binder, and solvent, and uniformly apply the brazing filler into the recessed structure on the surface of the diamond working layer substrate. Alternatively, use superhard materials, brazing filler, and organic polymers to form a diamond molded composite that is just smaller than the size of the recessed structure (including injection molding), and embed it into the recessed structure.

[0011] 5) Degreasing and sintering or brazing treatment: Degreasing and brazing are performed in a vacuum brazing furnace, or diamond multilayer brazed tools are obtained directly through sintering; 6) The obtained multi-layer brazed diamond tool is post-processed to meet the dimensional accuracy, and the edge is sharpened to meet the usage requirements.

[0012] As a further technical solution of the present invention, the main components in the feed are not limited to metal powders, and may also include inorganic material powders, ceramic microspheres or metal ceramic powders. In order to increase the wear-resistant material and adjust the hardness, a small amount of alumina, silicon carbide, tungsten carbide, diamond, cubic boron nitride, etc. can also be added, one or several of them. After the prepared feed is injection-molded, the working layer matrix of the diamond tool is sintered, and its sintering temperature is usually 0-50 °C higher than the melting point of the brazing material coated in the concave structure or the metal in the diamond forming composite embedded in the concave structure, or equal to the melting point of the brazing material coated in the concave structure or the metal in the diamond forming composite embedded in the concave structure, so as to ensure the stability of the matrix structure and the shape retention during the entire sintering or brazing process.

[0013] As a further technical solution of the present invention, the specific shape and depth of the concave structure are required to meet the design of superhard material tools. The shape can be circular, square, hexagonal or other shapes. The depth of the concave structure can provide the number of diamond layers, and its depth is generally 2-20 times the diameter of the diamond to meet the requirements of superhard material tools. In special cases, it can also exceed this depth; the concave structures are arranged according to requirements. Generally, the size d of the concave structure should be in the range of D < d < 2D (D is the diameter of the diamond), ensuring that the diamond can be coated or embedded in the concave structure. At the same time, it also ensures that there is generally one diamond in the vertical direction of the hole. At the same time, the spacing between the concave structures is adjusted according to the tool requirements; in the concave structure, for the needs of processing and manufacturing, not only single-particle diamonds are placed in the direction parallel to the joining plane. According to needs, the size d of the concave structure can also be greater than 2D. At this time, multiple diamonds can be placed in one layer of a unit concave structure, and a multi-layer brazed diamond tool with multiple diamonds in the unit concave structure can be obtained. The size of the concave structure in the working layer matrix determines the number of brazed diamond layers in the tool or the number of diamonds placed in each layer of the concave structure.

[0014] As a further technical solution of the present invention, the diamond working layer matrix units can be spliced into a specific shape to meet the requirements of diamond tools. Such as beads, multiple annular diamond working layer matrix units can be injection-molded. A layer of brazing material is coated on the outside of the matrix (steel cylinder). The multiple annular diamond working layer matrix units are spliced together and sleeved on the outside of the matrix (steel cylinder), and a bead is obtained through sintering or brazing. In order to increase the strength between the diamond working layer matrix unit and the diamond tool matrix, the bonding surface part between the diamond working layer matrix unit and the diamond matrix can be designed as certain grooves or special structures, or some specific grooves can be designed on the diamond matrix part to improve the welding strength between them.

[0015] As a further technical solution of the present invention, the diamond working layer matrix material includes Fe-based, nickel-based, tungsten-based and Cu-based elemental powders, alloy powders or mixed powders of elemental and alloy powders as materials for preparing the diamond working layer matrix unit, and may also be some or all inorganic material powders. As a further technical solution of the present invention, the binder system in the feed is a wax-based binder system, a water-based binder system, or a plastic-based binder system.

[0016] As a further technical solution of the present invention, the diamond working layer matrix unit is prepared by first mixing and granulating the prepared powder and binder to prepare granular feed, then forming the feed into a product blank of a specific shape on an injection molding machine, and then degreasing and sintering to obtain the desired diamond working layer matrix.

[0017] As a further technical solution of the present invention, the sintering temperature of the diamond working layer substrate unit is generally higher than or equal to the melting point temperature (0-50°C) of the solder system or the metal embedded in the diamond molded composite. Under the same temperature conditions, the solder or the metal embedded in the diamond molded composite generally reaches its melting point temperature, but sometimes it may not. However, under these temperature conditions, the solder or the embedded diamond molded composite material will definitely have a strong bonding performance with the diamond. Sintering is generally carried out under vacuum, protective atmosphere, or reducing atmosphere conditions.

[0018] As a further technical solution of the present invention, the diamond working layer substrate is first degreased, then diamond filler metal is applied to the recessed structure of the diamond working layer substrate, followed by sintering or brazing. At the same temperature, the diamond working layer substrate is sintered, but the diamond filler metal is brazed. Alternatively, the diamond working layer substrate can be degreased and sintered first, then diamond filler metal or diamond molding composite material can be embedded in the recessed structure of the diamond working layer substrate, followed by brazing or sintering. The optimal process is to apply diamond filler metal or embed diamond molding composite material in the recessed structure of the diamond working layer substrate after injection molding, and then heat up. At the same temperature, the diamond working layer substrate is degreased and sintered, while the diamond filler metal or diamond molding composite material is degreased and brazed, all in one step, simplifying the production process and reducing costs.

[0019] As a further technical solution of the present invention, the solder paste comprises a mixture of soldering powder, metal powder, diamond, polymer binder, and solvent; the soldering powder in the solder paste includes, but is not limited to, copper-based solder, nickel-based, silver-based elemental or alloy solder, etc.; the diamond concentration in the solder paste is added according to the requirements of diamond tools, and the diamond particle size is 5-1000 micrometers; the polymer binder is a commonly used type for preparing solder paste, which can be an aqueous or non-aqueous system, such as resin type, and will volatilize and decompose during the brazing or sintering process; the solvent is a commonly used type for preparing solder paste, such as toluene, water, etc., and will volatilize and decompose at high temperatures; the mass ratio of the alloy solder powder to the diamond particles is (0.5-20):1; the mass of the binder accounts for 0.1% to 60% of the mass of the metal solder powder.

[0020] As a further technical solution of the present invention, diamond can be replaced by cubic boron nitride, cemented carbide, polycrystalline superhard material, silicon carbide or other hard abrasives, or composite abrasives thereof.

[0021] As a further technical solution of the present invention, diamond tools are composite materials obtained by sintering diamond with other metals, non-metals or metal ceramics to meet the processing needs of cutting, grinding and polishing, including but not limited to beads, saw blades, grinding wheels, grinding discs, drill bits, dressing tools, etc.

[0022] As a further technical solution of the present invention, for final application, the diamond working layer matrix must be connected to a specific substrate. The diamond working layer matrix unit can be welded to the substrate after sintering and brazing, or the diamond working layer matrix unit and the substrate can be sintered and brazed together.

[0023] Soldering paste is prepared by uniformly mixing superhard materials (such as diamond particles), solder, binder, and solvent. The soldering paste is then applied to the recessed structures. The recessed structures on the diamond working layer substrate are designed based on the number of diamond layers, the diamond particle size, and the number of diamonds in the recessed structure of the substrate unit. This ensures the correct number of diamond layers and their arrangement.

[0024] The diamond concentration and particle size in the paste are added according to the requirements of diamond tool processing. Generally, the volume of diamond accounts for 10-30% of the total volume of diamond and alloy brazing. The polymer adhesive will volatilize and decompose without leaving any residue during the brazing or sintering process; The adhesive comprises a synthetic resin-based adhesive and a small amount of inorganic materials; The tool is placed in a brazing furnace and heated for brazing or sintering. After brazing, the surface is polished to expose the diamond as the cutting edge.

[0025] This invention provides a method for preparing multilayer brazed diamond tools based on injection-molded matrix units. The multilayer brazed diamond tool includes a diamond tool working layer matrix, diamond, and alloy brazing filler metal. The diamond particles can be brazed in multiple layers and orderly distributed in the diamond working layer matrix.

[0026] Compared with the prior art, the beneficial effects of this application are: 1. This invention addresses the problem of high grinding efficiency but short service life in existing single-layer brazed diamond tools by providing a method for fabricating multi-layer brazed diamond tools. The working layer substrate of the diamond tool is prepared by metal injection molding. The surface of this working layer substrate has regularly arranged recesses of specific depth to fill multiple layers of diamond and brazing material, resulting in both high grinding efficiency and long service life. This invention overcomes the short lifespan problem of current single-layer brazed tools, producing multi-layer brazed diamond tools with high abrasive grain exposure and good self-sharpening properties. It ensures the fabrication of multi-layer brazed diamond tools with controllable and regularly arranged diamond layers, and a long service life. Two material systems can be flexibly used. One material is used as the working layer substrate, prepared by metal injection molding, with a specific arrangement of recessed structures formed on its surface. Another material is a paste-like coating made by mixing brazing alloy powder, diamond, and organic polymer materials, which is then filled into the recessed structures of the diamond working substrate unit. Alternatively, a mixture of brazing alloy powder, binder, and superhard materials is injection molded or otherwise molded to obtain a shape that matches the recessed structure and embedded within it. After the diamond is fixed in the recessed structure, it undergoes brazing or sintering processes to ultimately obtain a multi-layer diamond brazed tool with a specific diamond arrangement and adjustable layer number. For large-size diamond tools that cannot be injection molded due to technical reasons, small injection-molded substrate units can be used, and these small substrate units can be spliced ​​and assembled into a specific form of large-size multi-layer diamond brazed tool to meet diverse application needs. 2. Using this method, a multi-layer brazed diamond bead structure can be prepared, which can significantly increase the service life of the brazed beads. Brazing ensures the bonding strength between the diamond and the working layer substrate. At the same time, the substrate is relatively easy to grind, ensuring that the brazed diamond has a high exposed portion relative to the working layer substrate and will not fall off. 3. The manufacturing method of this application can be used to manufacture multi-layer brazed diamond cutting heads, grinding heads, grinding discs, drill bits and other types of diamond tools. Similar to multi-layer brazed diamond beads, it has high processing efficiency while maintaining a long processing life, requires no secondary sharpening and has good working continuity. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the process of the present invention; Figure 2This is a schematic diagram of the diamond beads prepared according to the present invention; Figure 3 This is a schematic diagram of another diamond bead tool prepared according to the present invention; Figure 4 A model of the diamond grinding head prepared according to the present invention; Figure 5 The figure shows a model of the diamond saw blade head prepared according to the present invention. The left part is the model after the saw blade is assembled as a whole, and the right part is the assembly method of the injection molded matrix unit of a single saw blade head. Figure 6 A model of the diamond grinding disc prepared according to the present invention; Figure 7 The diamond grinding disc disassembled structure prepared according to the present invention is shown in the figure. 1 is a structure with specific grooves formed by injection molding in the form of injection-molded matrix unit, and 2 is the grinding disc matrix used to support the injection-molded matrix unit. Figure 8 The figure shows the position of the diamond and brazing filler prepared according to the present invention in the groove of the metal working layer substrate unit. In the figure, 3 is diamond, 4 is brazing filler, and 5 is tool working layer substrate unit. Figure 9 The figure shows a model of the diamond drill bit prepared according to the present invention. In the figure, 6 is the base unit of the drill bit working layer, 7 is the chip removal groove, and 8 is the side working layer. Figure 10 This is a schematic diagram showing the distribution of grooves on the working layer substrate unit of the diamond tool prepared according to the present invention; Figure 11 This is a schematic diagram showing the distribution of grooves on the tool working layer substrate unit prepared according to the present invention. Detailed Implementation

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below.

[0029] This invention provides a method for fabricating multilayer brazed diamond tools based on injection molding. The diamond tools include, but are not limited to, diamond beads, diamond grinding heads, diamond saw blades, diamond drill bits, or dressing tools. The process of fabricating the working layer matrix unit of the diamond tool using injection molding is identical to existing injection molding techniques.

[0030] The recessed structure of the working layer substrate unit is determined based on the size and number of brazed diamonds, and the arrangement rule of the recessed structure is determined based on grinding factors. The shape of the working layer substrate unit is determined based on the shape and size of the diamond tool. These dimensions are all based on consideration of dimensional shrinkage during the injection molding process. The arrangement method of the working layer substrate unit in the diamond tool is based on a comprehensive consideration of the grinding method, tool size, and shape.

[0031] Diamond is mixed with brazing filler metal to create a fluid solder paste, the manufacturing process of which is no different from current solder paste manufacturing processes. This paste is then applied to the recessed structures of the working layer substrate unit. Alternatively, diamond can be directly mixed with brazing powder and added to the working layer substrate unit.

[0032] The tool with the above coating is placed in a vacuum brazing furnace for heating or sintering; after completion, it is taken out and processed to expose the diamond, which can ensure the shape of the diamond and the diamond cutting edge.

[0033] Example 1: Preparation of multilayer brazed diamond beads using this method 1. The injection-molded beaded matrix unit form, according to Figure 2 The model's structure features a base unit with an outer diameter of 5.5 mm, an inner diameter of 3.5 mm, and a ring height of 2 mm. The entire bead string consists of four injection-molded base units. The diamond tool base unit has a ring height of 11 mm, an outer diameter of 3.5 mm, an inner diameter of 2.6 mm, and is made of 45# steel. The hole diameter within the base unit is 0.6 mm, the depth is 0.9 mm, and the center-to-center distance between holes is 1.8 mm. It is guaranteed to be a double-layer brazed diamond.

[0034] 2. The matrix unit material for the beaded working layer uses 85 parts of elemental powder with a mass ratio of Fe:Cu:Sn:Ni of 65:25:5:5. The powder particle size is 10-20 micrometers and it is semi-spherical. After the powder is completely mixed, 70 parts of polyoxymethylene, 7 parts / 8 parts of paraffin / E wax, 4 parts / 3 parts of HDPE / polyethylene wax, 4 parts of stearic acid derivative, 4 parts of EPDM, and 2 parts of fluorocarbon powder are mixed together, kneaded at 200°C for 35 minutes, crushed, and sieved to obtain the injection molding feedstock.

[0035] 3. The feedstock is used to prepare the working layer matrix unit through injection molding. This working layer matrix already has a regularly arranged recessed structure, such as... Figure 2 or Figure 3 As shown. The units obtained by injection molding are assembled into one piece to obtain... Figure 2 Right diamond bead working layer substrate. Figure 2 The method involves radial segmentation, where the front part is a beaded working layer matrix in the form of injection-molded matrix units, and the rear part is a diamond bead matrix assembled into one piece. To improve the bonding strength between the injection-molded matrix units and the diamond tool matrix during welding, some microstructures can be added to the bonding surfaces of the injection-molded matrix units and the diamond tool matrix during or after injection molding to improve their fit and increase their bonding area. These microstructures are not shown in the figure, and they also exist in other attached figures, but are not shown thereas. Figure 3 The front part is a step-by-step injection-molded beaded working layer matrix in the form of injection-molded matrix units, which is different. Figure 2The method involves axial segmentation, where the front part is a beaded working layer matrix in the form of injection-molded matrix units, and the rear part is a diamond beaded matrix assembled into one piece.

[0036] 4. Apply 50 / 60 mesh diamond and Cu85Sn10Ti5 brazing paste (Cu85Sn10Ti5 has a particle size of 200 mesh, approximately 74 micrometers) evenly to the recessed structures on the surface of the prepared working layer substrate.

[0037] 5. After the diamond plaster is applied, the diamonds are arranged in the recessed structure as follows: Figure 10 As shown.

[0038] 6. The beads are degreased with oxalic acid in a degreasing furnace, and then further degreased and brazed in a vacuum brazing furnace. The brazing temperature is set to 920℃ and held for 30 minutes to obtain multi-layered brazed diamond beads with three layers of diamonds arranged in an orderly manner. Figure 10 This image shows a diamond beaded product with a regularly arranged groove, where the groove is circular. However, other shapes are possible in practice, and not all can be listed here.

[0039] Example 2: Preparation of a single-layer brazed diamond grinding head using this method 1. First, a mold for the working layer substrate of the grinding head is designed to prepare the working layer substrate of the diamond grinding head by injection molding.

[0040] 2. The grinding head matrix material uses 90 parts of Fe50-Co30-Cu20 pre-alloyed powder, 75 parts of polyoxymethylene, 8 parts of polypropylene, 6 parts of polyol, and 3 parts of zinc fatty acid. The mixture is then stirred at 150℃ for 4 hours, crushed, sieved, and injection molded to obtain the feed material.

[0041] 3. The mixed feed material is injected into the molding die using an injection molding method, and the working layer matrix is ​​formed.

[0042] 4. Mix diamond with a particle size of 70 / 80 with BNi-2 solder paste, and then apply it evenly to the recessed structure on the surface of the prepared working layer substrate. Three diamond particles can be placed in each layer of each recessed structure.

[0043] 5. After the diamond plaster is applied, the diamonds are evenly distributed in each recessed structure, and each recessed structure contains one diamond.

[0044] 6. Degrease the grinding head in an oxalic acid degreasing furnace, then braze it in a vacuum brazing furnace at 1020℃ for 30 minutes. After brazing, a single layer of diamond is obtained with orderly diamond arrangement, such as... Figure 11 Diamond grinding heads arranged in a regular pattern.

[0045] Example 3: Preparation of multilayer diamond brazed saw blade head using this method 1. First, a saw blade working layer substrate mold was designed to prepare the saw blade head working layer substrate unit by injection molding. Due to the large size of the cutter head, its injection molding is difficult, so a step-by-step injection molding method is adopted for the injection molding substrate unit.

[0046] 2. The saw blade head base material uses Fe60Cu30Sn5Ni5 pre-alloy powder: 85%, polyoxymethylene resin (POM): 8%, high-density polyethylene (HDPE): 3%, high-density polypropylene (HDPP): 3%, ABS: 0.9%, stearic acid: 0.1%, which are mixed together and kneaded at 150℃ for 35 minutes, crushed, sieved, and injection molded feedstock.

[0047] 3. The mixed and sieved feedstock is injected into the molding die using injection molding. The surface of this working layer substrate already has a regularly arranged concave structure, such as... Figure 5 The structure of the saw blade head is shown.

[0048] 4. Mix diamond with a particle size of 50 / 60 with Cu80Sn10Ti10 solder paste and apply it evenly to the recessed structure on the surface of the prepared working layer substrate.

[0049] 5. After the diamond paste is applied, the diamonds are arranged in the recessed structure as follows: Figure 8 As shown in the figure, the structure can be a through hole, an oblique hole, or a stepped hole, which is beneficial for the arrangement of adsorbed diamonds.

[0050] 6. Place the saw blade head in a vacuum brazing furnace, set the temperature to 920℃ and hold for 30 minutes for brazing. After brazing, a single layer of diamond is obtained with the diamonds arranged in an orderly manner, such as... Figure 10 Diamond saw blade tips arranged in a regular pattern.

[0051] Example 4: Preparation of multilayer diamond brazed grinding discs using this method 1. First, a saw blade working layer substrate mold was designed to prepare the saw blade head working layer substrate unit by injection molding. Due to the large size of the grinding disc tool, its injection molding process is difficult, so a step-by-step injection molding method was adopted for the substrate unit.

[0052] 2. The grinding disc substrate material uses pre-processed alloy material. The injection-molded substrate unit uses 95 parts Cu-Sn-Ni powder as the substrate. The binder is mainly composed of polyoxymethylene (POM), combined with 5 parts high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), stearic acid (SA), and antioxidant. The ratio of high-density polyethylene (HDPE), ethylene-vinyl acetate copolymer (EVA), stearic acid (SA), and antioxidant is: POM 80%, HDPE 10%, EVA 5%, SA 4%, and antioxidant 1%.

[0053] The mixture is stirred together at 150℃ for 35 minutes, then crushed and screened to obtain the feed.

[0054] 3. The mixed feedstock is injected into the molding die using injection molding. The surface of this working layer substrate already has a regularly arranged recessed structure, such as... Figure 7 (1) The grinding disc substrate unit structure is shown in the figure, and each unit is injection molded. It is then bonded to the grinding disc substrate using an adhesive or a mixture of adhesive and solder, resulting in the final structure shown in the figure. Figure 6 As shown, Figure 6 The structural difference between the left and right sides is the difference in the shape of the injection molding matrix unit of the working layer matrix.

[0055] 4. Mix diamond with a particle size of 70 / 80 with BNi-2 solder paste and apply it evenly to the recessed structure on the surface of the prepared injection-molded matrix unit.

[0056] 5. After the diamond paste is applied, the diamonds are arranged in the recessed structure as follows: Figure 8 As shown.

[0057] 6. Degreasing method: Oxalic acid catalytic degreasing combined with thermal degreasing is employed. The oxalic acid catalytic degreasing temperature range is 50-145℃, and the time is 4-12 hours; the subsequent thermal degreasing temperature is 120-600℃, and the time is 4-5 hours. The entire grinding disc is placed in a vacuum brazing furnace, set to 920℃ and held for 30 minutes for brazing. After brazing, a multi-layered diamond structure is obtained, with the diamonds arranged in an orderly manner, as shown below. Figure 11 A diamond grinding disc product with a regular arrangement. The groove shape in this picture is hexagonal.

[0058] Example 5: Preparation of multi-layer diamond drill bits using this method 1. First, a drill bit working layer substrate mold was designed to prepare the drill bit working layer substrate unit through injection molding. Due to the complexity of the drill bit front working layer, its injection molding process is quite difficult. Therefore, a step-by-step injection molding process using injection molding substrate units was adopted.

[0059] 2. The drill bit matrix material uses pre-processed alloy material. The injection-molded matrix unit uses 50 parts of Cu80Sn10Ni10 pre-alloyed powder and 50 parts of binder. The binder composition is 60% paraffin wax (PW), supplemented with 20% polypropylene (PP), 10% polyethylene (PE), and 10% stearic acid (SA). All materials are mixed and kneaded at 150℃ for 35 minutes to form the injection molding feedstock, which is then crushed and sieved.

[0060] 3. The screened feed material is injected into the molding die using injection molding. The surface of this working layer substrate already has a regularly arranged concave structure, such as... Figure 9 The intermediate grinding disc substrate unit structure is shown in the figure, and each unit is injection molded. It is then bonded to the drill bit substrate using an adhesive or a mixture of adhesive and solder, resulting in the final structure shown. Figure 9 As shown.

[0061] 4. Mix 35 / 40 diamond particles with BN-2 solder, then add a polymer binder and toluene solvent to form a solder paste. Apply the paste evenly to the recessed structure on the surface of the prepared injection-molded matrix unit. At this time, the size of the recessed structure is larger than enough to accommodate three 35 / 40 diamond particles, but smaller than enough to accommodate four 35 / 40 diamond particles.

[0062] 5. After the diamond paste is applied, the diamonds are arranged in the recessed structure as follows: Figure 8 As shown.

[0063] 6. Solvent degreasing: Dissolve the paraffin wax using an organic solvent (such as n-heptane), followed by thermal degreasing: gradually increase the temperature (e.g., 150-280℃) to decompose the binder, combined with an inert atmosphere protection, for approximately 3-5 hours. Place the entire drill bit in a vacuum brazing furnace, set the temperature to 930℃ and hold for 30 minutes for brazing. After brazing, a multi-layered diamond structure is obtained, with the diamonds arranged in an orderly manner, such as... Figure 11 Diamond drill bits arranged in a regular pattern.

Claims

1. A method for preparing a multilayer brazed diamond tool based on injection molding, characterized in that, It includes the following steps: 1) Prepare an injection molding feed: Mix 50 - 95 wt% of metal powder or inorganic material powder, 3 - 50 wt% of polymer binder, and 10 - 30% of solvent, and carry out internal mixing at 150 - 200 °C for 35 minutes to 4 hours. Then, perform crushing and screening to obtain a feed meeting the requirements of the injection molding process. 2) Prepare a diamond working layer matrix unit: Use the feed prepared in step 1) to prepare a diamond working layer matrix unit through injection molding technology. The surface of the matrix unit has recesses. 3) Assemble a large - sized diamond working layer matrix: Piece together and assemble the small - sized matrix units prepared by injection molding technology to form a large - sized diamond working layer matrix. 4) Place diamonds and brazing filler metal: Evenly apply brazing paste into the recess structures on the surface of the diamond working layer matrix; or use a mixture of superhard materials, brazing filler metal, and organic polymers to mold a diamond - forming composite slightly smaller than the size of the recess structure, and embed it into the recess structure. 5) Debinding and sintering or brazing treatment: Conduct debinding treatment and brazing in a vacuum brazing furnace, or directly obtain a diamond multi - layer brazed tool through sintering. 6) Perform size machining and edge sharpening on the obtained diamond multi - layer brazed tool.

2. The preparation method according to claim 1, characterized in that, The feed also includes inorganic material powder, ceramic microspheres, or metal ceramic powder. After the feed is injection - molded and sintered, a working layer matrix of the diamond tool is obtained. The sintering temperature is 0 - 50 °C higher than the melting point of the metal coated with brazing material or embedded in the diamond - forming composite in the recess structure.

3. The preparation method according to claim 1, characterized in that, The feed also includes one or several of alumina, silicon carbide, tungsten carbide, diamond, cubic boron nitride, etc., and their dosage is 10 - 50% of the volume of the diamond working layer matrix unit.

4. The preparation method according to claim 1, characterized in that, The shape of the recess structure is circular, square, or hexagonal. The depth of the recess structure is greater than twice the diameter of the diamond. The size d of the recess structure is in the range of D < d < 2D, where D is the diameter of the diamond.

5. The preparation method according to claim 1, characterized in that, The binder system in the feed is a wax - based binder system, a water - based binder system, or a plastic - based binder system.

6. The preparation method according to claim 1, characterized in that, The preparation method of the diamond working layer matrix unit is to first prepare the prepared powder and binder into a granular feed through mixing and granulation, then form a green product of a specific shape on an injection molding machine, and then obtain the required diamond working layer matrix through debinding and sintering.

7. The preparation method according to claim 1, characterized in that, The sintering temperature of the diamond working layer matrix unit is 0 - 50 °C higher than the melting point temperature of the brazing solder system or the metal embedded in the diamond - forming composite. The sintering is carried out under vacuum, protective atmosphere, or reducing atmosphere conditions.

8. The preparation method according to claim 1, characterized in that, First, the diamond working layer substrate is degreased, then diamond brazing filler metal is applied to the recessed structure of the diamond working layer substrate, and then sintered or brazed at the same temperature; or first, the diamond working layer substrate is degreased and sintered, then diamond brazing filler metal or diamond molding composite material is embedded in the recessed structure of the diamond working layer substrate, and then brazed or sintered; or after injection molding the diamond working layer substrate, diamond brazing filler metal or diamond molding composite material is applied to the recessed structure of the diamond working layer substrate, and then the temperature is raised. At the same temperature, the diamond working layer substrate is degreased and sintered, and the diamond brazing filler metal or diamond molding composite material is degreased and brazed.

9. The preparation method according to claim 1, characterized in that, The soldering paste comprises soldering powder, metal powder, diamond, polymer binder, and solvent; the soldering powder in the soldering paste is copper-based, nickel-based, silver-based, or alloy solder; the diamond concentration in the soldering paste is added according to the requirements of diamond tools, and the diamond particle size is 5-1000 micrometers; the mass ratio of the alloy solder powder to diamond particles is (0.5-20):1; the binder accounts for 0.1% to 60% of the mass of the metal solder powder.

10. The preparation method according to claim 1, characterized in that, The diamond working layer matrix unit is sintered and brazed before being welded into the matrix; or it is sintered and brazed together with the diamond working layer matrix unit and the matrix.

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