A grinding wheel with linear cooling channel and double-wire 3D printing preparation method thereof

Abstract

The present invention discloses a grinding wheel containing linear cooling channels and a double-wire 3D printing preparation method thereof, wherein the grinding wheel is composed of a working layer and a metal matrix, a plurality of linear cooling channels are evenly distributed on the surface of the working layer in the circumferential direction, the width of the linear cooling channels is 1 to 5 mm, and the spacing between any two adjacent linear cooling channels is 1 to 10 mm; the working layer is composed of an alloy matrix and abrasive particles, and the abrasive particles are selected from diamond particles or CBN particles. The present invention adopts double-wire 3D printing technology to accurately print out the designed miniature linear cooling channels, ensure the uniformity of powder distribution in the diamond or CBN grinding wheel of the linear cooling channel, and the linear cooling channels can not only improve the chip removal efficiency, but also cut off the heat transfer route when the grinding wheel is working to reduce the thermal damage to the diamond, improve the temperature field of the working layer and the workpiece interface, and improve the service life of the grinding wheel and the processing quality of the workpiece surface.

Description

Technical Field

[0001] The present invention relates to the technical field of superhard abrasive tool manufacturing, and in particular to a grinding wheel containing a linear cooling channel and a double-wire 3D printing preparation method thereof. Background Art

[0002] During grinding, diamond or CBN grinding wheels rely on diamond or CBN abrasives to remove excess material from the workpiece surface. Due to the high rotation speed during grinding, a large amount of grinding heat is easily generated, causing the local temperature of the grinding area to be too high, making it very easy for the workpiece surface to be ground and burn during the grinding process, making it difficult to ensure the quality of part processing. Although the use of coolant is the most direct way to control the temperature of the grinding area, since the coolant cannot directly reach the inside of the grinding area and only acts on the outer surface of the workpiece, it cannot effectively reduce the temperature of the processing surface. At the same time, the grinding wheel is prone to severe clogging due to long-term grinding, which will affect the quality of the part processing surface.

[0003] By designing cooling channels on the surface of the grinding wheel working layer, the heat transfer route can be cut off, so that the continuously moving heat source in the grinding area becomes an intermittently moving heat source, which is conducive to alleviating the problem of heat source concentration on the surface of the workpiece, thereby reducing the thermal damage of the diamond on the working surface of the grinding wheel. At the same time, the coolant can more easily enter the grinding area, which can not only play a better cooling role, but also help chip removal, reduce the probability of grinding chips sticking to the workpiece surface, and have a better flushing effect. However, the manufacture of dense, miniature linear cooling channels is a problem that cannot be solved by ordinary powder metallurgy methods. It is necessary to develop a high-precision, structurally customized, and highly efficient manufacturing technology to realize the preparation of diamond or CBN grinding wheels with linear cooling channels. Summary of the invention

[0004] To overcome the deficiencies of the prior art, the first object of the present invention is to provide a grinding wheel with dense, miniature linear cooling channels. By designing the linear cooling channels, the heat transfer path is cut off, and the thermal damage to the diamond and the workpiece surface that may be caused by the grinding wheel is reduced.

[0005] The second object of the present invention is to provide a double-wire 3D printing preparation method for a grinding wheel containing linear cooling channels. The 3D printing manufacturing process can achieve high-efficiency production of dense and miniature linear cooling channels, effectively control production costs, and optimize product performance.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] The invention discloses a grinding wheel containing linear cooling channels. The grinding wheel consists of a working layer and a metal matrix. A plurality of linear cooling channels are evenly distributed on the surface of the working layer in a circumferential direction. The width of the linear cooling channels is 1 to 5 mm, and the spacing between any two adjacent linear cooling channels is 1 to 10 mm. The working layer consists of an alloy matrix and abrasive particles, and the abrasive particles are selected from diamond particles or CBN particles.

[0008] The present invention provides a grinding wheel with linear cooling channels, wherein a series of dense micro linear cooling channels are evenly distributed along the circumference of the grinding wheel, which can not only ensure that the coolant continuously enters the grinding area, but also ensure the stability of the water flow, and avoid the phenomenon that the amount of liquid sprayed is too large when the channel is too wide, causing the workpiece to vibrate. During the grinding process, the grinding wheel and the workpiece are ground in an intermittent contact manner, and the corresponding grinding force also changes periodically, which is conducive to the crushing of the workpiece surface and improves the processing efficiency of the workpiece. At the same time, the linear cooling channels on the surface of the grinding wheel are conducive to the entry of grinding fluid and the discharge of cutting debris, thereby effectively reducing the grinding temperature and the problem of debris accumulation.

[0009] In a preferred solution, the thickness of the working layer is 5 to 12 mm, the depth of the linear cooling channel is 2 to 8 mm, and the thickness of the working layer is at least 2 mm greater than the depth of the linear cooling channel.

[0010] The inventors have found that the bonding between the working layer and the metal substrate can be ensured by making the thickness of the working layer greater than the depth of the linear cooling channel by 2 mm or more.

[0011] In a preferred embodiment, in the working layer, the mass ratio of the alloy matrix to the abrasive particles is 1-19:1-5.

[0012] In a preferred embodiment, the alloy matrix is ​​composed of the following by mass percentage: 70-90wt% copper powder, 5-15wt% tin powder, 0-2wt% titanium powder, 1-5wt% nickel powder, and 0-8wt% cobalt powder.

[0013] The present invention also provides a double-wire 3D printing preparation method for a grinding wheel containing a linear cooling flow channel, comprising: mixing pre-alloy powder, abrasive particles, and a binder A to obtain a working layer mixture, kneading and granulating the working layer mixture to obtain a working layer granular material, and drawing to obtain a working layer filamentary material, mixing a ceramic mixed powder and a binder B to obtain a linear cooling flow channel mold mixture, kneading and granulating the linear cooling flow channel mold mixture to obtain a linear cooling flow channel mold granular material, and drawing to obtain a linear cooling flow channel mold filamentary material, placing the working layer filamentary material and the linear cooling flow channel mold filamentary material at double feed ports corresponding to a double-wire 3D printing device, respectively, printing according to a set printing model and slicing parameters to obtain a working layer green body containing a linear cooling flow channel mold, assembling the working layer green body with a metal matrix to obtain a grinding wheel green body, degreasing the grinding wheel green body to obtain a degreased green body, sintering the degreased green body to obtain a grinding wheel sintered body, removing the linear cooling flow channel mold in the grinding wheel sintered body, and obtaining a grinding wheel containing a linear cooling flow channel.

[0014] In a preferred embodiment, the particle size of the pre-alloyed powder is 10 to 100 μm, and the particle size of the abrasive grains is 20 to 150 μm.

[0015] The inventors have found that when the particle sizes of abrasive particles and pre-alloyed powders are controlled within the above range, the printing accuracy and finished product performance are optimal.

[0016] In a preferred embodiment, the mass ratio of the pre-alloyed powder to the abrasive particles is 1-19:1-5.

[0017] In a preferred embodiment, in the working layer mixture, the volume ratio of the total mass of the alloy powder and the abrasive particles to the binder A is 1-4:1-3.

[0018] In a preferred embodiment, the binder A comprises the following components: 40-60 wt% ethylene-methyl methacrylate copolymer, 20-40 wt% polypropylene, 15-20 wt% polyethylene, 2-6 wt% vegetable oil, and 1-5 wt% polyvinyl alcohol.

[0019] The binder A of the present invention adopts ethylene-methyl methacrylate copolymer as the skeleton material in the binder. The ethylene-methyl methacrylate copolymer has high thermal stability, and can be subjected to shearing and high temperature in the mixing rotor and the extrusion screw, and can maintain its inherent flow performance without chemical crosslinking reaction. At the same time, the polymer also has good reactivity, crystallinity and fluidity, and has good compatibility with a variety of plastics. Polypropylene has excellent mechanical properties, and excellent rigidity and bending fatigue resistance can ensure the strength of the wire. Blending polyethylene with polypropylene can enhance the outstanding performance of each component and make up for the deficiencies in the performance of each component. During the blending modification, the shear force can cause part of the macromolecular chain to be cut off to form free radicals and form block copolymers. These new copolymers can also effectively increase the volume of polypropylene. Vegetable oil and polyvinyl alcohol can play a good lubrication and dispersion role, and ensure the uniformity of the distribution of each material. Under the synergistic effect of the above-mentioned binder A components, the obtained wire has good flexibility, fluidity, and uniformity, so as to print a green blank with uniform performance.

[0020] In a preferred solution, the diameter of the working layer filamentary material is 1.70-1.80 mm.

[0021] In a preferred embodiment, the ceramic mixed powder is selected from any 2 to 3 of alumina powder, aluminum nitride powder, silicon dioxide powder, silicon carbide powder and graphite powder.

[0022] In the present invention, ceramic mixed powder is used as the raw material for preparing the linear cooling channel mold with polymer. The ceramic mixed powder can play a good supporting role in the degreasing and sintering process, thereby ensuring the integrity of the cooling channel. However, due to the high melting point of the ceramic mixed powder, it cannot achieve density under the sintering conditions of the grinding wheel, which is also convenient for subsequent removal and forming a complete linear channel. If a polymer is used to prepare a linear cooling channel mold, a large amount of polymer in the cooling channel will evaporate during hot degreasing. At this time, since the material in the cooling channel has evaporated and cannot play a supporting role, placing the degreased part in the sintering furnace for pressure sintering will cause the surface of the working layer to be flattened and a linear cooling channel cannot be formed.

[0023] In a preferred embodiment, the volume ratio of the ceramic mixed powder to the binder B is 1-3:1-4.

[0024] In a preferred embodiment, the binder B comprises the following components: 40-55wt% styrene thermoplastic elastomer, 30-40wt% polyphenylene ether, 10-30wt% acrylonitrile-butadiene-styrene copolymer, 1-5wt% stearic acid, and 1-2wt% dodecyltrimethylammonium chloride.

[0025] The inventors found that due to the chemical inertness of the components of the ceramic mixed powder, it is impossible to prepare qualified printing filaments using binder A or other conventional binder systems. Binder B is required to prepare qualified printing filaments. In order to adapt to the chemical inertness of the ceramic mixed powder, the binder B used in the present invention uses dodecyltrimethylammonium chloride and stearic acid as surfactants and dispersants, respectively. This surfactant combined with the dispersant can effectively regulate the surface properties of the ceramic particles and the interaction between the particles, and form a monomolecular film on the surface of the ceramic particles, thereby achieving the effect of modifying the powder surface and improving the compatibility of the ceramic particles with other polymer materials. In addition, the skeleton material in the binder B is a styrene-based thermoplastic elastomer, which has the advantages of high strength, good flexibility, good elasticity, and small deformation. It can be mixed with a variety of materials such as fillers, modifiers, plasticizers, and other resins, and has good compatibility. Polyphenylene ether has high heat resistance and excellent mechanical strength, which can provide strength for the filament, ensuring that the filament can pass smoothly through the printer extrusion gear and be delivered to the extrusion nozzle. Acrylonitrile-butadiene-styrene copolymer is a thermoplastic polymer material with high strength, good toughness and easy processing. It can be blended with polyphenylene ether and has good compatibility, achieving the purpose of enhancing the performance of the wire.

[0026] Preferably, the diameter of the linear cooling channel mold filament is 1.70-1.80 mm.

[0027] In the actual operation process, a grinding wheel with linear cooling channels is established in the computer 3D modeling software, and the model file is stored in the STL format. The slicing software is then used to directly cut the file so that the thickness of each layer is machinable. The final slicing file is imported into the FDM dual-filament 3D printing device; then the two types of filaments are respectively placed in the feed port of the printer, the working parameters of the dual-filament 3D printer are set, the equipment is started, and the working layer green body is printed.

[0028] In a preferred solution, the thickness of the bottom layer of the working layer green body is ≥2 mm, preferably 2 to 10 mm.

[0029] In a preferred embodiment, during the printing process, the printed layer thickness is 0.1 to 0.3 mm, and the printing speed is 10 to 50 mm / s.

[0030] In a preferred embodiment, the degreasing is carried out under a hydrogen atmosphere, and the degreasing process is: first, the temperature is increased from room temperature to 100-120°C at a heating rate of 10-15°C / min, and the temperature is kept for 0.5-1h; then, the temperature is increased to 200-250°C at a heating rate of 3-5°C / min, and the temperature is kept for 0.5-1.5h; then, the temperature is increased to 350-400°C at a heating rate of 1-3°C / min, and the temperature is kept for 0.5-2h; finally, the temperature is increased to 500-600°C at a heating rate of 2-6°C / min, and the temperature is kept for 0.5-2h.

[0031] In the thermal debinding process of the present invention, two different binders in the present invention are adapted, and based on the difference in the pyrolysis temperature range of different components of the binder, a gradient heating mode is adopted for step-by-step debinding, which can effectively ensure the integrity of the green body and the removal effect of the binder in the green body, and avoid debinding problems such as bulging, cracking, and excessive binder residue.

[0032] The preferred solution is that the sintering process is: heating from room temperature to 300°C to 400°C within 1 to 5 minutes, keeping the temperature for 1 to 3 minutes, then heating to 500°C to 600°C within 1 to 3 minutes, keeping the temperature for 1 to 3 minutes; finally heating to 700°C to 900°C within 1 to 3 minutes, and heating at 60 to 200 kg / cm 2 Under the sintering pressure of , keep warm for 1 to 5 minutes to obtain the grinding wheel sintered body.

[0033] The sintering process of the present invention can optimize the performance of the final grinding wheel. If the pressure is too high, it is easy to cause serious overflow, and the grinding wheel may be physically damaged when the pressure is too high, while the grinding wheel cannot be sintered densely if the pressure is too low. Too high temperature will cause a large amount of low-melting-point metal to be lost, and it may also cause damage to diamond particles. Too low temperature will not be able to achieve melting of metal materials and effective metallurgical bonding. Therefore, too high or too low temperature will lead to insufficient performance of the grinding wheel.

[0034] In actual operation, after the insulation at 700℃~900℃ is completed, the pressure is released and the furnace is cooled to obtain a grinding wheel sintered body containing linear cooling channels.

[0035] The inventors found that, due to the high melting point of the raw material of the selected linear cooling channel mold, it is not possible to achieve density under the sintering conditions of the grinding wheel, which is convenient for subsequent cleaning and forming a complete linear channel.

[0036] Beneficial effects:

[0037] The present invention provides a grinding wheel with a linear cooling channel, wherein the linear cooling channel can effectively improve the chip removal and heat dissipation capabilities of the diamond grinding wheel, thereby improving the grinding efficiency and reducing the thermal damage to the diamond and the workpiece, extending the service life of the diamond grinding wheel, and greatly reducing the processing cost. The diamond grinding wheel has broad application prospects in the processing of cemented carbide and hard and brittle materials.

[0038] The present invention combines double-wire 3D printing technology with the production of diamond grinding wheels. With the help of this technology, the limitations of traditional processes for making complex structure tools can be broken. The needs of contemporary grinding technology can be met by flexibly designing and modifying the grinding wheel structure, and the designed micro-linear cooling channels can be accurately printed to ensure the uniformity of powder distribution in the linear cooling channel diamond or CBN grinding wheel, optimize the grinding performance of the diamond or CBN grinding wheel, and also improve production efficiency and reduce production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of a diamond or CBN grinding wheel with linear cooling channels;

[0040] Figure 1 In the figure, 1-working layer, 2-linear cooling channel, 3-metal matrix. DETAILED DESCRIPTION

[0041] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific implementation modes.

[0042] Example 1

[0043] The working layer thickness of the diamond grinding wheel is designed to be 8mm, the flow channel depth is 5mm, the linear cooling flow channel width is 3mm, and the spacing between adjacent flow channels is 3mm; the powder raw materials used are diamond powder, alloy powder and ceramic-based mixed powder, the particle size of the alloy powder is 50μm, the particle size of the diamond powder is 30μm, the particle size of the alumina powder is 50μm, the particle size of the aluminum nitride powder is 50μm, and the particle size of the silicon dioxide powder is 25μm; the mass ratio of the alloy powder to the diamond micropowder is 1:5, and the volume ratio of the powder to the special binder A is 1:4; the alloy powder is composed of 80wt% copper powder, 10wt% tin powder, 5wt% cobalt powder, 3wt% nickel powder and 2wt% titanium Powder composition; the mass ratio of alumina powder, aluminum nitride powder and silicon dioxide powder in the ceramic-based mixed powder is 10:10:1, and the volume ratio of the ceramic-based mixed powder to the special binder B is 1:4; the components of the special binder A include 50wt% of ethylene-methyl methacrylate copolymer, 30wt% of polypropylene, 15wt% of polyethylene, 3wt% of vegetable oil, and 2wt% of polyvinyl alcohol; the components of the special binder B include 45wt% of styrene-based thermoplastic elastomer, 30wt% of polyphenylene ether, 20wt% of acrylonitrile-butadiene-styrene copolymer, 3wt% of stearic acid, and 2wt% of dodecyltrimethylammonium chloride.

[0044] This example provides a double-wire 3D printing manufacturing process for a linear cooling channel diamond grinding wheel, including the following steps:

[0045] a. The working layer raw materials (diamond, alloy powder and special binder A) and the linear cooling channel raw materials (ceramic-based mixed powder and special binder B) are mixed and stirred to obtain a working layer mixture and a linear cooling channel mixture, and then the two mixtures are mixed, granulated and drawn to obtain metal-based diamond composite wires and ceramic-based composite wires, wherein the temperature and rotation speed of the mixing and drawing process are 160°C and 10rpm;

[0046] b. Use SOLIDWORKS and other software to draw a linear cooling channel diamond grinding wheel model, then import the model file into the slicing software and set the printing parameters, with a printing layer thickness of 0.2 mm and a printing speed of 30 mm / s. Connect the filamentary materials to two feeding transmission mechanisms respectively, and then print under the specified path of the computer modeling software to obtain a diamond grinding wheel green body;

[0047] c. After assembling the green body and the metal matrix, place them in a degreasing furnace for degreasing. Heat from room temperature to 100°C at 10°C / min, and then keep it warm for 0.5 hours; heat from 100°C to 200°C at 3°C / min, and then keep it warm for 0.5 hours; heat from 200°C to 350°C at 1°C / min, and then keep it warm for 1 hour; heat from 350°C to 500°C at 2°C / min, and then keep it warm for 1 hour; cool in the furnace and take out the degreased sample. After degreasing, place it in a sintering furnace for sintering. Heat from room temperature to 350°C within 1 minute, and then keep it warm for 1 minute. Then heat from 350°C to 500°C within 1 minute, and then keep it warm for 1 minute; finally, heat from 500°C to 750°C within 2 minutes, and the sintering pressure is 70Kg / cm 2 , and then keep warm for 2 minutes; then start to release the pressure and cool with the furnace, and take it out to get the linear cooling channel diamond grinding wheel sintered body. After sintering, remove the ceramic matrix composite material in the linear cooling channel, and then perform dressing and polishing to get the linear cooling channel diamond grinding wheel.

[0048] The prepared linear cooling channel diamond grinding wheel was used to grind the cemented carbide block. The surface roughness of the cemented carbide after processing was R a The surface roughness of the cemented carbide after machining is 0.238 μm, compared with the conventional grinding wheel under the same conditions. a A decrease of 26.8%.

[0049] Example 2

[0050] The working layer thickness of the designed CBN grinding wheel is 8mm, the flow channel depth is 5mm, the linear cooling flow channel width is 3mm, and the spacing between adjacent flow channels is 3mm; the raw materials used are CBN powder, alloy powder and ceramic-based mixed powder, the particle size of the alloy powder is 60μm, the particle size of the CBN powder is 40μm, the particle size of the aluminum nitride powder is 50μm, the particle size of the silicon dioxide powder is 50μm, and the particle size of the graphite is 15μm; the mass ratio of the alloy powder to the CBN micropowder is 1:5, and the volume ratio of the powder to the special binder A is 1:2; the alloy powder contains 80wt% copper powder, 10wt% tin powder, 5wt% cobalt powder, 3wt% nickel powder and 2wt% Titanium powder; the mass ratio of aluminum nitride powder, silicon dioxide powder and graphite powder in the ceramic-based mixed powder is 10:10:1, and the volume ratio of the ceramic-based mixed powder to the special binder B is 1:4; the ingredients of the special binder A include 50wt% of ethylene-methyl methacrylate copolymer, 30wt% of polypropylene, 15wt% of polyethylene, 3wt% of vegetable oil, and 2wt% of polyvinyl alcohol; the ingredients of the special binder B include 45wt% of styrene-based thermoplastic elastomer, 30wt% of polyphenylene ether, 20wt% of acrylonitrile-butadiene-styrene copolymer, 3wt% of stearic acid, and 2wt% of dodecyltrimethylammonium chloride.

[0051] This example provides a double-wire 3D printing manufacturing process for a linear cooling channel CBN grinding wheel, including the following steps:

[0052] a. The working layer raw materials (CBN powder, alloy powder and special binder A) and the linear cooling channel raw materials (ceramic-based mixed powder and special binder B) are mixed and stirred to obtain a working layer mixture and a cooling channel mixture, and then the two mixtures are mixed, granulated and drawn to obtain metal-based diamond composite wires and ceramic-based composite wires, wherein the temperature and rotation speed of the mixing and drawing process are 160°C and 10rpm;

[0053] b. Use SOLIDWORKS and other software to draw a linear cooling channel CBN grinding wheel model, then import the model file into the slicing software and set the printing parameters, with a printing layer thickness of 0.2 mm and a printing speed of 30 mm / s. Connect the two prepared filamentary materials to two feeding transmission mechanisms respectively, and then print under the specified path of the computer modeling software to obtain a CBN grinding wheel green body;

[0054] c. After assembling the green body and the metal matrix, place them in a degreasing furnace for degreasing. Heat from room temperature to 100°C at 15°C / min, and then keep it warm for 0.5 hours; heat from 100°C to 200°C at 3°C / min, and then keep it warm for 1 hour; heat from 200°C to 350°C at 1°C / min, and then keep it warm for 1.5 hours; heat from 350°C to 500°C at 2°C / min, and then keep it warm for 1.5 hours; cool in the furnace and take out the degreased sample. After degreasing, place it in a sintering furnace for sintering. Heat from room temperature to 350°C within 1 minute, and then keep it warm for 1 minute. Then heat from 350°C to 500°C within 1 minute, and then keep it warm for 1 minute; finally, heat from 500°C to 750°C within 2 minutes, and the sintering pressure is 90Kg / cm 2 , and then keep warm for 2 minutes; then start to release the pressure and cool with the furnace, and take it out to get the linear cooling channel CBN grinding wheel sintered body. After sintering, remove the ceramic matrix composite material in the linear cooling channel, and then perform dressing and polishing to get the linear cooling channel CBN grinding wheel.

[0055] The prepared linear cooling channel diamond grinding wheel was used to grind the cemented carbide block. The surface roughness of the cemented carbide after processing was R a The surface roughness of the cemented carbide after machining is 0.243 μm, compared with the conventional grinding wheel under the same conditions. a A decrease of 25.3%.

[0056] Example 3

[0057] The working layer thickness of the diamond grinding wheel is designed to be 8mm, the flow channel depth is 5mm, the linear cooling flow channel width is 2mm, and the spacing between adjacent flow channels is 2mm; the raw materials used are diamond powder, alloy powder and ceramic-based mixed powder, the particle size of the alloy powder is 30μm, the particle size of the diamond powder is 50μm, the particle size of the aluminum nitride powder in the ceramic mixed powder is 50μm, the particle size of the silicon dioxide powder is 50μm, and the particle size of the silicon carbide powder is 15μm; the mass ratio of the alloy powder to the diamond micropowder is 1:5, and the volume ratio of the powder to the special binder A is 1:2; the alloy powder contains 80wt% copper powder, 10wt% tin powder, 5wt% cobalt powder, 3wt% % nickel powder and 2wt% titanium powder; the mass ratio of aluminum nitride powder, silicon dioxide powder and silicon carbide powder in the ceramic-based mixed powder is 2:2:1, and the volume ratio of the ceramic-based mixed powder to the binder B is 1:4; the ingredients of the special binder A include 55wt% ethylene-methyl methacrylate copolymer, 30wt% polypropylene, 10wt% polyethylene, 3wt% vegetable oil, and 2wt% polyvinyl alcohol; the ingredients of the special binder B include 45wt% styrene thermoplastic elastomer, 30wt% polyphenylene ether, 20wt% acrylonitrile-butadiene-styrene copolymer, 3wt% stearic acid, and 2wt% dodecyltrimethylammonium chloride.

[0058] This example provides a double-wire 3D printing manufacturing process for a linear cooling channel diamond grinding wheel, including the following steps:

[0059] a. The working layer raw materials (diamond, alloy powder and special binder A) and the linear cooling channel raw materials (ceramic-based mixed powder and special binder B) are mixed and stirred to obtain a working layer mixture and a linear cooling channel mixture, and then the two mixtures are mixed, granulated and drawn to obtain metal-based diamond composite wires and ceramic-based composite wires, wherein the temperature and rotation speed of the mixing and drawing process are 160°C and 10rpm;

[0060] b. Use SOLIDWORKS and other software to draw a linear cooling channel diamond grinding wheel model, then import the model file into the slicing software and set the printing parameters, the printing layer thickness is 0.2mm, the printing speed is 30mm / s, and the two prepared filamentary materials are connected to two feeding transmission mechanisms respectively, and then print under the specified path of the computer modeling software to obtain the diamond grinding wheel green body;

[0061] c. After assembling the green body and the matrix, place them in a debinding furnace for debinding, heating from room temperature to 100°C at 12°C / min, and then keep them warm for 0.5 hours; heating from 100°C to 200°C at 3°C / min, and then keep them warm for 1 hour; heating from 200°C to 350°C at 1°C / min, and then keep them warm for 1.5 hours; heating from 350°C to 500°C at 2°C / min, and then keep them warm for 1.5 hours; cooling in the furnace, take out the debinded sample. After debinding, place it in a sintering furnace for sintering, heating from room temperature to 350°C within 1 minute, and then keep it warm for 1 minute, then heating from 350°C to 500°C within 1 minute, and then keep it warm for 1 minute; finally heating from 500°C to 750°C within 2 minutes, and the sintering pressure is 130Kg / cm 2 , and then keep warm for 2 minutes; then start to release the pressure and cool with the furnace, and take it out to get the linear cooling channel diamond grinding wheel sintered body. After sintering, remove the ceramic matrix composite material in the linear cooling channel, and then perform dressing and polishing to get the linear cooling channel diamond grinding wheel.

[0062] The prepared linear cooling channel diamond grinding wheel was used to grind the cemented carbide block. The surface roughness of the cemented carbide after processing was R a 0.132μm, compared with the use of ordinary grinding wheels under the same conditions, the surface roughness of the cemented carbide after processing is R a A decrease of 59.4%.

[0063] Comparative Example 1

[0064] Other conditions are the same as those in Example 1, and the width of the linear cooling channel is designed to be 7 mm. Since the linear cooling channel is wide, the surface roughness of the workpiece increases significantly, and the grinding efficiency decreases significantly.

[0065] Comparative Example 2

[0066] The other conditions were the same as those in Example 2, but the ceramic mixed powder was mixed and kneaded with the special binder A. Since the binder A was not effectively compatible with the ceramic mixed powder, the kneaded material was in a fluid state and could not be drawn.

[0067] Comparative Example 3

[0068] The other conditions were the same as those in Example 3, but the sintering pressure was set to 220 Kg / cm 2 Due to the excessive sintering pressure, the problem of material loss occurred, and a large amount of ceramic material infiltrated into the working layer of the grinding wheel, causing the cooling channel to deform, making it impossible to prepare a qualified linear cooling channel grinding wheel.

[0069] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A double-wire 3D printing preparation method for a grinding wheel containing a linear cooling channel, characterized in that: Pre-alloyed powder, abrasive grains and binder A are mixed to obtain a working layer mixture, the working layer mixture is kneaded and granulated to obtain a working layer granular material, and the working layer filamentary material is obtained by wire drawing, the ceramic mixed powder and binder B are mixed to obtain a linear cooling channel mold mixture, the linear cooling channel mold mixture is kneaded and granulated to obtain a linear cooling channel mold granular material, and the linear cooling channel mold filamentary material is obtained by wire drawing, the working layer filamentary material and the linear cooling channel mold filamentary material are respectively placed in the double feed ports corresponding to the double-wire 3D printing device, and the working layer green body containing the linear cooling channel mold is printed according to the set printing model and slicing parameters, the working layer green body is assembled with the metal matrix to obtain a grinding wheel green body, the grinding wheel green body is degreased to obtain a degreased green body, the degreased green body is sintered to obtain a grinding wheel sintered body, and the linear cooling channel mold in the grinding wheel sintered body is removed to obtain a grinding wheel containing a linear cooling channel; The ceramic mixed powder is selected from any 2 to 3 of alumina powder, aluminum nitride powder, silicon dioxide powder, silicon carbide powder, and graphite powder; The volume ratio of the ceramic mixed powder to the binder B is 1-3:1-4; The binder B comprises the following ingredients: 40-55wt% styrene thermoplastic elastomer, 30-40wt% polyphenylene ether, 10-30wt% acrylonitrile-butadiene-styrene copolymer, 1-5wt% stearic acid, and 1-2wt% dodecyltrimethylammonium chloride; The diameter of the linear cooling channel mold filament is 1.70-1.80 mm; The grinding wheel consists of a working layer and a metal matrix. A plurality of linear cooling channels are evenly distributed circumferentially on the surface of the working layer. The width of the linear cooling channels is 1 to 5 mm, and the spacing between any two adjacent linear cooling channels is 1 to 10 mm. The working layer consists of an alloy matrix and abrasive particles, and the abrasive particles are selected from diamond particles or CBN particles.

2. The double-wire 3D printing preparation method of a grinding wheel containing a linear cooling channel according to claim 1, characterized in that: The particle size of the pre-alloyed powder is 10-100 μm, and the particle size of the abrasive grains is 20-150 μm; the mass ratio of the pre-alloyed powder to the abrasive grains is 1-19:1-5.

3. The double-wire 3D printing preparation method of a grinding wheel containing a linear cooling channel according to claim 1, characterized in that: In the working layer mixture, the volume ratio of the total mass of the alloy powder and the abrasive particles to the binder A is 1-4:1-3; The binder A comprises the following ingredients: 40-60wt% ethylene-methyl methacrylate copolymer, 20-40wt% polypropylene, 15-20wt% polyethylene, 2-6wt% vegetable oil, and 1-5wt% polyvinyl alcohol; The diameter of the working layer filamentary material is 1.70-1.80 mm.

4. The double-wire 3D printing preparation method of a grinding wheel containing a linear cooling channel according to claim 1, characterized in that: The thickness of the bottom layer of the working layer green body is ≥2 mm. During the printing process, the printed layer thickness is 0.1-0.3 mm, and the printing speed is 10-50 mm / s.

5. The double-wire 3D printing preparation method of a grinding wheel containing a linear cooling channel according to claim 1, characterized in that: The degreasing is carried out under a hydrogen atmosphere, and the degreasing process is: firstly, the temperature is increased from room temperature to 100-120°C at a heating rate of 10-15°C / min, and the temperature is kept for 0.5-1h; then, the temperature is increased to 200-250°C at a heating rate of 3-5°C / min, and the temperature is kept for 0.5-1.5h; then, the temperature is increased to 350-400°C at a heating rate of 1-3°C / min, and the temperature is kept for 0.5-2h; finally, the temperature is increased to 500-600°C at a heating rate of 2-6°C / min, and the temperature is kept for 0.5-2h.

6. The double-wire 3D printing preparation method of a grinding wheel containing a linear cooling channel according to claim 1, characterized in that: The sintering process is as follows: heating from room temperature to 300°C-400°C within 1-5 minutes, keeping the temperature for 1-3 minutes, then heating to 500°C-600°C within 1-3 minutes, keeping the temperature for 1-3 minutes; finally heating to 700°C-900°C within 1-3 minutes, heating at 60-200Kg / cm 2 Under the sintering pressure of , keep warm for 1 to 5 minutes to obtain the grinding wheel sintered body.

7. A double-wire 3D printing method for preparing a grinding wheel containing a linear cooling channel according to any one of claims 1 to 6, characterized in that: The thickness of the working layer is 5-12 mm, the depth of the linear cooling channel is 2-8 mm, and the thickness of the working layer is greater than the depth of the linear cooling channel by more than 2 mm.

8. A double-wire 3D printing method for preparing a grinding wheel containing a linear cooling channel according to any one of claims 1 to 6, characterized in that: In the working layer, the mass ratio of the alloy matrix to the abrasive particles is 1-19:1-5; The alloy matrix is ​​composed of the following by mass percentage: 70-90wt% copper powder, 5-15wt% tin powder, 0-2wt% titanium powder, 1-5wt% nickel powder, and 0-8wt% cobalt powder.

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