Anti-chatter grinding method of multi-body guide blades based on gradient grinding wheel and nano-cooling

Abstract

The present invention discloses a method for anti-chatter grinding of multi-jointed guide blades based on a gradient grinding wheel and nano-cooling. The grinding method includes the following steps: designing and preparing a gradient porous energy-consuming grinding wheel; installing the trimmed gradient porous energy-consuming grinding wheel on the spindle of a grinding machine; clamping the multi-jointed guide blade workpiece to be ground below the gradient porous energy-consuming grinding wheel, and simultaneously installing a nano-jet directional injection device and a suction and chip removal device on one side of the multi-jointed guide blade workpiece; starting the grinding machine to rotate the gradient porous energy-consuming grinding wheel, and simultaneously starting the nano-jet directional injection device and the suction and chip removal device, and grinding the multi-jointed guide blade workpiece according to the designed grinding process and grinding parameters. The present invention innovatively proposes a synergistic system combining a gradient porous energy-consuming grinding wheel with nano-directional cooling, which cuts off the vibration transmission path at the source, realizes precise thermal control of the slit area, and effectively solves the problem of the thermal coupling effect of the blade during the grinding process.

Description

Technical Field

[0001] The invention belongs to the technical field of precision machining of aero-engine turbine blades, and in particular relates to a chatter mark-resistant grinding method for multi-unit guide blades based on a gradient grinding wheel and nano-cooling. Background Art

[0002] As the core component of the high-pressure turbine section of an aircraft engine, the processing quality of the multi-jointed guide vanes directly affects the aerodynamic efficiency and service reliability of the engine. Such blades are usually made of nickel-based high-temperature alloys or titanium-aluminum alloys and have complex spatial curved surface structures, such as twisted blades, thin-walled edge plates, and multi-jointed integral designs.

[0003] However, existing grinding processes face multiple technical bottlenecks in achieving high-precision machining. First, chatter marks are a prominent problem. Due to the insufficient rigidity of the thin-walled blade structure (thickness 1-3 mm), the grinding wheel-workpiece system is susceptible to vibration coupling, which easily excites resonance in the 50-500 Hz frequency range, with measured amplitudes reaching 5-8 μm. This causes periodic surface ripples (waviness > 0.3 μm), which in severe cases can cause a 10-15% decrease in the blade's aerodynamic performance. Second, thermal damage is difficult to control. The instantaneous temperature in the grinding zone can exceed 600°C. The resulting localized high temperature can induce subsurface microcracks exceeding 15 μm in depth, which are potential sources of fatigue failure. Furthermore, the life and cooling efficiency of the grinding wheel are low. Due to the high viscosity of high-temperature alloys, the grinding chips are easily welded and adhered to the surface of the grinding wheel, resulting in a pore blockage rate of up to 40% in traditional homogeneous grinding wheels and a service life of less than 60 pieces. At the same time, the conventional pouring cooling method has a narrow flow channel (width <3mm) and poor coolant permeability, so the actual heat exchange efficiency is less than 40%, making it difficult to effectively suppress thermal deformation.

[0004] While the industry is currently attempting to improve machining quality using technologies such as high-rigidity machine tools and constant-force grinding, the results have been limited, achieving only partial improvements. For example, increasing spindle rigidity can reduce vibration amplitude by 20-30%, but it still cannot eliminate the periodic characteristics of chatter marks. While constant-force grinding can stabilize cutting forces, it struggles to effectively suppress dynamic load fluctuations caused by sudden changes in curvature of multi-piece guide vanes (measured grinding force fluctuations range from ±15N). Furthermore, existing cooling technologies are limited by their extensive control: a single cooling mode struggles to match the varying thermal loads across different blade regions (for example, temperature rise gradients exceeding 200°C in areas such as the blade body, root, and leading edge), leading to problems such as localized overburning and residual stress imbalances. Therefore, there is an urgent need to develop a collaborative optimization solution that integrates vibration suppression, thermal damage control, and process stability improvement to fill the gap in high-precision, anti-chatter mark grinding technology for multi-piece guide vanes and meet the urgent need for zero-defect blade machining for mass production of domestically produced aircraft engines. Summary of the Invention

[0005] In order to solve the problems existing in the prior art, the present invention provides an anti-chatter mark grinding method for multi-unit guide blades based on a gradient grinding wheel and nano-cooling. The grinding method includes the following steps in order:

[0006] Step 1: Design and prepare a gradient porous energy-consuming grinding wheel. According to the characteristics of the multi-unit guide blade machining surface, use a diamond roller to dress the gradient porous energy-consuming grinding wheel. Install the dressed gradient porous energy-consuming grinding wheel on the spindle of the grinding machine.

[0007] Step 2: Clamp the multi-piece guide blade workpiece to be ground under the gradient porous energy consumption grinding wheel, and install the nano-jet directional injection device and the suction and chip removal device on one side of the multi-piece guide blade workpiece;

[0008] Step 3: Start the grinding machine to rotate the gradient porous energy consumption grinding wheel, and at the same time start the nano-jet directional injection device and the suction and chip removal device to grind the multi-unit guide blade workpiece according to the designed grinding process and grinding parameters.

[0009] Preferably, in step one, the gradient porous energy-consuming grinding wheel consists of three layers, which are, from the inside to the outside, an inner grinding wheel layer, a middle grinding wheel layer and an outer grinding wheel layer; the inner grinding wheel layer, the middle grinding wheel layer and the outer grinding wheel layer are independently prepared, and then the three layers are combined together, a silane coupling agent is coated between the outer grinding wheel layer and the middle grinding wheel layer, a metal transition layer is sprayed between the middle grinding wheel layer and the inner grinding wheel layer, and then hot isostatic pressing is used for compounding, the hot isostatic pressing temperatures of the outer grinding wheel layer, the middle grinding wheel layer and the inner grinding wheel layer are 950°C, 200°C and 600°C respectively, the applied pressure is 150MPa, the holding time is 120min, and argon gas is introduced for protection.

[0010] An axial hole is set at the center of the gradient porous energy-consuming grinding wheel, and the axial hole, the inner layer of the grinding wheel, the middle layer of the grinding wheel and the outer layer of the grinding wheel are concentric circle structures; the width ratio of the inner layer of the grinding wheel, the middle layer of the grinding wheel and the outer layer of the grinding wheel is 1.5:1:2, the width of the inner layer of the grinding wheel is the difference between the outer diameter of the inner layer of the grinding wheel and the radius of the axial hole, the width of the middle layer of the grinding wheel is the difference between the outer diameter of the middle layer of the grinding wheel and the outer diameter of the inner layer of the grinding wheel, and the width of the outer layer of the grinding wheel is the difference between the outer diameter of the outer layer of the grinding wheel and the outer diameter of the middle layer of the grinding wheel, and the thickness of the three layers is the same.

[0011] In any of the above schemes, preferably, in step one, the inner layer of the grinding wheel is a hexagonal honeycomb structure and is made of titanium alloy material; the inner layer of the grinding wheel is prepared by laser additive manufacturing technology, with a laser power of 300-500W, a scanning speed of 800-1200mm / s, and a spot diameter of 70-90μm.

[0012] In any of the above schemes, preferably, in step 1, the grinding wheel middle layer is made of a composite material of stainless steel and silicone, and its preparation method is as follows: first, a metal mold is designed according to the shape and size of the grinding wheel middle layer; then, stainless steel wires with a diameter of 0.1-0.5 mm are stacked in circles in the metal mold and pressed to obtain a stainless steel matrix, the pressing temperature is 200-220°C, the pressure is 100-150 MPa, and the pressing time is 1.5-2h; finally, the silicone is heated to a fluid state, and the fluid silicone is injected into the stainless steel matrix to obtain the grinding wheel middle layer, the injection temperature is 60-70°C, the injection pressure is 80-120 MPa, and the holding time is 30-40min. The density of the composite material of stainless steel and silicone is 3.5-4.5g / cm 3 .

[0013] In any of the above schemes, it is preferred that in step one, the outer layer of the grinding wheel is a composite structure formed by a microcrystalline ceramic outer layer body and cubic boron nitride abrasives, and its preparation method is: first, the microcrystalline ceramic outer layer body is prepared by laser additive manufacturing technology, with a laser power of 500-700W, a scanning speed of 1200-1800mm / s, and a spot diameter of 90-120μm; then, the cubic boron nitride abrasives are implanted into the outer circumferential side of the microcrystalline ceramic outer layer body according to the designed abrasive arrangement method by electrostatic sand implantation technology; finally, the microcrystalline ceramic outer layer body implanted with cubic boron nitride abrasives is placed in a sintering furnace for sintering to obtain the outer layer of the grinding wheel.

[0014] The mass percentages of various substances in the microcrystalline ceramic outer layer body are 25-35wt% of silicon dioxide, 55-65wt% of aluminum oxide, and 5-15wt% of yttrium oxide; a plurality of circular holes are evenly arranged on the outer circumferential side surface of the microcrystalline ceramic outer layer body, the diameter of the circular holes is 50-55μm, the depth is 20-25μm, and the coverage rate of the plurality of circular holes on the outer circumferential side surface is 15-20%.

[0015] The median particle size of the cubic boron nitride abrasive is 80-120 μm, and the abrasive arrangement method is as follows: first, the outer circumferential side surface of the microcrystalline ceramic outer layer body is evenly divided into twelve sand-planting areas. If the outer circumferential side surface of the microcrystalline ceramic outer layer body is unfolded, it is a strip-shaped rectangle, whose length is the outer circumference of the microcrystalline ceramic outer layer body and whose width is the thickness of the microcrystalline ceramic outer layer body; then, a sand-planting area is selected as the first sand-planting area, and cubic boron nitride abrasive is implanted according to the abrasive arrangement path of the first sand-planting area; finally, cubic boron nitride abrasive is implanted in the second sand-planting area, the third sand-planting area, and the twelfth sand-planting area in a clockwise or counterclockwise direction according to the abrasive arrangement path of each sand-planting area.

[0016] The abrasive arrangement path of the first sand planting area is as follows: the thickness direction of the microcrystalline ceramic outer layer body is defined as the horizontal direction, and the outer circumferential direction is defined as the vertical direction. S1, starting from the left edge, arrange the first row of abrasive grains horizontally until it is arranged to 2 / 3 of the thickness of the microcrystalline ceramic outer layer body, and arrange the second row of abrasive grains horizontally from the middle position of the first abrasive grain and the second abrasive grain in the first row, and arrange the third row of abrasive grains horizontally from the middle position of the first abrasive grain and the second abrasive grain in the second row, and so on, until it is arranged to the right edge, which is the Nth row of abrasive grains. The number of abrasive grains in each row is the same, and the lateral spacing between the centers of two adjacent abrasive grains in the same row is 120-300μm. The abrasive grains in two adjacent rows are arranged horizontally. The vertical spacing between the centers of the particles is 120-300 μm; S2, starting from the right edge to the left edge, arrange the abrasive particles in the N+1th row horizontally from the middle position between the first abrasive particle and the second abrasive particle in the Nth row, and arrange the abrasive particles in the N+2th row horizontally from the middle position between the first abrasive particle and the second abrasive particle in the N+1th row, and so on, until the left edge is arranged. The number of abrasive particles in each row is the same, and the horizontal spacing between the centers of two adjacent abrasive particles in the same row is 120-300 μm, and the vertical spacing between the centers of abrasive particles in two adjacent rows is 120-300 μm; S3, repeat path S1 to S2 until the abrasive particles in the first sand planting area are arranged.

[0017] The abrasive arrangement path of the second sand planting area is: based on the abrasive arrangement path of the first sand planting area, the second row of abrasives are vertically translated to the first row, the third row of abrasives are vertically translated to the second row, and so on, until the abrasive arrangement of the second sand planting area is completed.

[0018] The abrasive arrangement path of the third sand planting area is: based on the abrasive arrangement path of the second sand planting area, the second row of abrasives are vertically translated to the first row, the third row of abrasives are vertically translated to the second row, and so on, until the abrasive arrangement of the third sand planting area is completed.

[0019] This process is deduced by analogy until the abrasive grains in the twelfth sand planting area are arranged.

[0020] After the abrasive arrangement of the twelve sand-planting areas on the outer circumferential side of the outer layer of the microcrystalline ceramic blank is completed, it is placed in a sintering furnace for sintering. The sintering process is: heating from room temperature to 800°C at a rate of 5-10°C / min, continuing to heat from 800°C to 1000°C at a rate of 8-12°C / min, continuing to heat from 1000°C to 1200°C at a rate of 10-15°C / min, continuing to heat from 1200°C to 1600°C at a rate of 10-15°C / min, and then keeping warm for 4-5 hours. After the insulation is completed, cool from 1600°C to room temperature at a rate of 50-100°C / min. Argon protection is introduced during the entire sintering process.

[0021] In any of the above schemes, preferably, in step one, twenty circulating cooling microchannels are evenly arranged inside the gradient porous energy consumption grinding wheel by using laser drilling technology, and the circulating cooling microchannels penetrate the inner layer of the grinding wheel, the middle layer of the grinding wheel and the outer layer of the grinding wheel, wherein the part of the circulating cooling microchannel located in the outer layer of the grinding wheel is an S-shaped structure; and the diameter of the circulating cooling microchannel is 0.5-0.8 mm.

[0022] In any of the above schemes, it is preferred that in step 2, the nanojet directional injection device includes a porous ceramic nozzle and a hydraulic pump, the porous ceramic nozzle is connected to the hydraulic pump, the diameter of the porous ceramic nozzle is 10-20 mm, and a plurality of injection holes are arranged on the outlet end face thereof, the diameter of the injection holes is 0.1-0.3 mm, and the distance between the centers of two adjacent injection holes is 2 mm.

[0023] In any of the above schemes, preferably, in step 2, the suction and chip removal device includes a titanium alloy chip suction tube and a vacuum pump, the titanium alloy chip suction tube is connected to the vacuum pump, and the diameter of the titanium alloy chip suction tube is 5-10 mm.

[0024] In any of the above schemes, preferably, in step one and step two, the circulating cooling microchannel and the nanojet directional injection device both use a nano-cooling liquid, and the mass percentage of each substance in the nano-cooling liquid is 75-85wt% of the base liquid, 5-15wt% of aluminum oxide, and 5-15wt% of graphene; the mass percentage of each substance in the base liquid is 68-73wt% of deionized water, 22-27wt% of ethylene glycol, and 4-6wt% of carboxymethyl cellulose; the particle size of the aluminum oxide is 40-50nm, and the thickness of the graphene layer is 3-5nm.

[0025] In any of the above solutions, preferably, in step three, the multi-unit guide vane workpiece is ground according to the designed grinding process and grinding parameters, and sequentially undergoes three processes of rough grinding, semi-finishing grinding and finishing grinding.

[0026] In the rough grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 80-120 m / s, the depth of a single grinding is 0.4-0.6 mm, and the machining allowance is 0.3-0.5 mm; a circulating cooling microchannel is used for primary cooling, and the applied pressure is 6-8 MPa.

[0027] In the semi-finishing grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 60-80m / s, the depth of a single grinding is 0.1-0.2mm, and the machining allowance is 0.1-0.2mm; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressures of the circulating cooling microchannel and the nano-jet directional injection device are both 8-10MPa, and the applied pressure of the suction and chip removal device is 2-3MPa.

[0028] In the fine grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 30-50m / s, the depth of a single grinding is 0.03-0.05mm, and it is ground to the required size; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel is 8-10MPa, the applied pressure of the suction and chip removal device is 2-3MPa, and the nano-jet directional injection device performs intermittent spray cooling with an intermittent frequency of 1KHz and an applied pressure of 8-10MPa.

[0029] In the present invention, the grinding machine tools, sintering furnaces, hydraulic pumps, vacuum pumps, etc. used are all traditional equipment, and there are no special requirements for the equipment model, structure, etc.; the laser additive manufacturing technology used is a traditional technology, as long as the process parameters such as laser power, scanning speed, and spot diameter meet the requirements of the present invention; the electrostatic sand planting technology, laser drilling technology, hot isostatic pressing technology, plasma spraying technology, etc. used are also traditional technologies, and there are no special requirements for process parameters.

[0030] In the present invention, the inner layer, the middle layer and the outer layer of the grinding wheel are prepared independently, and then the three layers are combined together. A silane coupling agent, model KH-550, is coated between the outer layer and the middle layer of the grinding wheel to enhance the bonding strength between the ceramic and the metal rubber. A plasma-sprayed metal transition layer, specifically a NiCrAlY transition layer, is used between the middle layer and the inner layer of the grinding wheel. The thickness of the layer is 50 μm to match the thermal expansion coefficient. Hot isostatic pressing was used for compounding. The hot isostatic pressing temperatures of the outer layer, middle layer and inner layer of the grinding wheel were 950℃, 200℃ and 600℃ respectively. Gradient temperature control was adopted to sinter the ceramic of the outer layer of the grinding wheel, solidify the silicone of the middle layer of the grinding wheel, and diffuse weld the inner layer of the grinding wheel. The applied pressure was 150MPa and isotropic pressure was applied to eliminate the interlayer pores. The holding time was 120min to ensure the mutual diffusion of interface elements and the thickness of the diffusion layer was greater than 5μm. Argon gas with a purity of 99.99% was introduced for protection to prevent oxidation and promote interface diffusion.

[0031] In the present invention, a plurality of circular holes are uniformly arranged on the outer circumference of the microcrystalline ceramic outer layer blank to accommodate grinding debris. The outer circumference of the microcrystalline ceramic outer layer blank is evenly divided into twelve sand-planting areas, and cubic boron nitride abrasive grains are implanted in the sand-planting areas to perform the grinding operation. Twenty circulating cooling microchannels are uniformly arranged within the interior of the gradient porous energy-consuming grinding wheel. These circulating cooling microchannels penetrate the inner, middle, and outer layers of the grinding wheel. Nano-coolant is pressed into these circulating cooling microchannels, forming forced convection, thereby removing heat from the gradient porous energy-consuming grinding wheel body. The arrangement of the circular holes, the implantation of the cubic boron nitride abrasive grains, and the establishment of the circulating cooling microchannels are completed independently. The circular holes, the cubic boron carbide abrasive grains, and the circulating cooling microchannels may partially overlap, but this does not affect their respective functions.

[0032] In the present invention, the gradient porous energy-consuming grinding wheel is divided into three layers. The function of the inner layer of the grinding wheel is mainly to provide structural support and reduce the weight of the grinding wheel, so that the grinding wheel can achieve the effect of lightweight design; the function of the middle layer of the grinding wheel is mainly to block the vibration transmission path and dissipate energy; the function of the outer layer of the grinding wheel is mainly to directly participate in the cutting of parts. The cubic boron nitride abrasive grains in the twelve sand-planting areas have the characteristics of asymmetric arrangement, breaking the traditional periodic arrangement method.

[0033] The present invention employs a three-stage cooling system. The first stage utilizes a circulating cooling microchannel, which forces convection of nano-coolant through the gradient porous energy-consuming grinding wheel, removing heat from the grinding wheel itself and reducing the grinding temperature between the grinding wheel and the part. The second stage utilizes a nano-jet directional injection device, which generates a jet of nano-coolant through a porous ceramic nozzle, directly impacting the grinding arc area for efficient cooling. The third stage utilizes a suction chip removal device, which removes high-temperature chips, removing at least 25% of the heat, suppressing the increase in grinding temperature, and preventing chips from embedding into the workpiece surface or being crushed by the grinding wheel a second time, thereby reducing surface scratches.

[0034] The existing technology for anti-chatter mark grinding of multi-unit guide blades faces three major technical bottlenecks: (1) the difficulty in suppressing chatter marks due to the lack of rigidity of the blades themselves; (2) the instantaneous high temperature generated during the grinding of complex blade surfaces can easily induce subsurface microcracks; (3) the narrow flow channel structure limits the effectiveness of traditional cooling methods, resulting in shortened grinding wheel life, low cooling efficiency, and difficulty in controlling blade thermal deformation.

[0035] In response to the technical bottlenecks faced by the existing technology, the present invention innovatively proposes a "gradient porous energy-consuming grinding wheel + nano-directional cooling" synergistic system based on the anti-chatter grinding method of the gradient grinding wheel and nano-cooling multi-body guide blade. This scheme suppresses the chatter source through the damping characteristics of the gradient composite material, cuts off the vibration transmission path from the source, and combines the directional penetration of the nano-coolant to achieve precise thermal control of the slit area, effectively solving the problem of the thermal-mechanical coupling effect of the multi-body guide blade during the grinding process, and significantly improving the integrity of the workpiece processing surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A process flow chart of a preferred embodiment of the anti-chatter mark grinding method of multi-unit guide blades based on a gradient grinding wheel and nano-cooling according to the present invention;

[0037] Figure 2 for Figure 1 A schematic diagram of the positional relationship among the multi-piece guide vane workpiece, the gradient porous energy-consuming grinding wheel, the nano-jet directional injection device, and the suction and chip removal device in the illustrated embodiment;

[0038] Figure 3 for Figure 1 A schematic structural diagram of a gradient porous energy consumption grinding wheel in the embodiment shown;

[0039] Figure 4 for Figure 1 A schematic diagram of the arrangement structure of cubic boron nitride abrasive grains in the first sand-planting area of ​​the illustrated embodiment;

[0040] Figure 5 for Figure 1 A schematic diagram of the arrangement structure of cubic boron nitride abrasive particles in the second sand-planting area of ​​the illustrated embodiment;

[0041] Figure 6 for Figure 1 A schematic diagram of the arrangement structure of cubic boron nitride abrasive grains in the third sand-planting area of ​​the illustrated embodiment;

[0042] Figure 7 for Figure 1 Schematic diagram of the nano-jet directional injection device in the embodiment shown;

[0043] Figure 8 for Figure 1 A schematic diagram of the suction and chip removal device in the illustrated embodiment;

[0044] Figure 9 for Figure 1 A photograph of the surface morphology of the multi-piece guide vane workpiece (radial arc surface portion of the edge plate) after grinding in the illustrated embodiment.

[0045] Notes in the figure:

[0046] 1- gradient porous energy-consuming grinding wheel, 101- axial hole, 102- grinding wheel inner layer, 103- grinding wheel middle layer, 104- grinding wheel outer layer, 105- circulating cooling microchannel, 106- S-shaped structure, 107- first sand-planting area, 108- second sand-planting area, 109- third sand-planting area, 110- cubic boron nitride abrasive;

[0047] 2-nanojet directional injection device, 201-porous ceramic nozzle, 202-hydraulic pump;

[0048] 3- Suction and chip removal device, 301- titanium alloy chip suction pipe, 302- vacuum pump;

[0049] 4-Multi-unit guide blade workpiece;

[0050] 5- Grinding arc area. DETAILED DESCRIPTION

[0051] In order to further understand the content of the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0052] Example 1:

[0053] like Figure 1-8 As shown, according to a preferred embodiment of the present invention, the anti-chatter mark grinding method of the multi-unit guide blade based on the gradient grinding wheel and nano-cooling, the grinding method includes the following steps in order:

[0054] Step 1: Design and prepare a gradient porous energy-consuming grinding wheel 1, use a diamond roller to dress the gradient porous energy-consuming grinding wheel 1 according to the characteristics of the multi-unit guide blade processing surface, and install the dressed gradient porous energy-consuming grinding wheel 1 on the spindle of the grinding machine;

[0055] Step 2: The multi-piece guide blade workpiece 4 to be ground is clamped under the gradient porous energy consumption grinding wheel 1, and the nano-jet directional injection device 2 and the suction and chip removal device 3 are installed on one side of the multi-piece guide blade workpiece 4;

[0056] Step 3: Start the grinding machine to rotate the gradient porous energy-consuming grinding wheel 1, and simultaneously start the nano-jet directional injection device 2 and the suction and chip removal device 3, and grind the multi-unit guide blade workpiece 4 according to the designed grinding process and grinding parameters.

[0057] In step one, the gradient porous energy-consuming grinding wheel 1 consists of three layers, which are, from the inside to the outside, a grinding wheel inner layer 102, a grinding wheel middle layer 103 and a grinding wheel outer layer 104; the grinding wheel inner layer 102, the grinding wheel middle layer 103 and the grinding wheel outer layer 104 are independently prepared, and then the three layers are combined together, KH-550 silane coupling agent is coated between the grinding wheel outer layer and the grinding wheel middle layer, and a NiCrAlY transition layer is sprayed between the grinding wheel middle layer and the grinding wheel inner layer with a thickness of 50 μm, and then hot isostatic pressing is used for compounding, and the hot isostatic pressing temperatures of the grinding wheel outer layer, the grinding wheel middle layer and the grinding wheel inner layer are 950°C, 200°C and 600°C, respectively, the applied pressure is 150 MPa, the holding time is 120 min, and argon protection is introduced.

[0058] The center of the gradient porous energy-consuming grinding wheel 1 is provided with an axial hole 101. The axial hole 101, the inner layer 102, the middle layer 103, and the outer layer 104 are concentric circles. The width ratio of the inner layer 102, the middle layer 103, and the outer layer 104 is 1.5:1:2. The width of the inner layer 102 is the difference between the outer diameter of the inner layer 102 and the radius of the axial hole 101. The width of the middle layer 103 is the difference between the outer diameter of the middle layer 103 and the outer diameter of the inner layer 102. The width of the outer layer 104 is the difference between the outer diameter of the outer layer 104 and the outer diameter of the middle layer 103. The thickness of the three layers is the same. In this embodiment, the diameter of the gradient porous energy-consuming grinding wheel is 300 mm, the thickness is 30 mm, and the diameter of the axial hole is 76.2 mm.

[0059] In step 1, the inner layer 102 of the grinding wheel is a hexagonal honeycomb structure and is made of titanium alloy material; the inner layer 102 of the grinding wheel is prepared by laser additive manufacturing technology, with a laser power of 400W, a scanning speed of 1000mm / s, and a spot diameter of 80μm.

[0060] In step 1, the grinding wheel intermediate layer 103 is made of a composite material of stainless steel and silicone. The preparation method is as follows: first, a metal mold is designed according to the shape and size of the grinding wheel intermediate layer; then, stainless steel wires with a diameter of 0.3 mm are stacked in circles in the metal mold and pressed to obtain a stainless steel matrix. The pressing temperature is 210°C, the pressure is 125 MPa, and the pressing time is 1.8 h; finally, the silicone is heated to a fluid state and the fluid silicone is injected into the stainless steel matrix to obtain the grinding wheel intermediate layer. The injection temperature is 65°C, the injection pressure is 100 MPa, and the holding time is 35 min. The density of the composite material of stainless steel and silicone is 4 g / cm 3 .

[0061] In step one, the outer layer 104 of the grinding wheel is a composite structure formed by a microcrystalline ceramic outer layer body and cubic boron nitride abrasive grains, and its preparation method is as follows: first, the microcrystalline ceramic outer layer body is prepared by laser additive manufacturing technology, with a laser power of 600W, a scanning speed of 1500mm / s, and a spot diameter of 105μm; then, the cubic boron nitride abrasive grains are implanted into the outer circumferential side of the microcrystalline ceramic outer layer body according to the designed abrasive arrangement method by electrostatic sand implantation technology; finally, the microcrystalline ceramic outer layer body implanted with cubic boron nitride abrasive grains is placed in a sintering furnace for sintering to obtain the outer layer of the grinding wheel.

[0062] The mass percentages of each substance in the microcrystalline ceramic outer layer body are 30wt% silicon dioxide, 60wt% aluminum oxide, and 10wt% yttrium oxide; a plurality of circular holes are evenly arranged on the outer circumferential side surface of the microcrystalline ceramic outer layer body, the diameter of the circular holes is 52μm, the depth is 22μm, and the coverage rate of the plurality of circular holes on the outer circumferential side surface is 18%.

[0063] The median particle size of the cubic boron nitride abrasive 110 is 100 μm, and the abrasive arrangement method is as follows: first, the outer circumferential side surface of the microcrystalline ceramic outer layer body is evenly divided into twelve sand-planting areas. If the outer circumferential side surface of the microcrystalline ceramic outer layer body is unfolded, it is a strip-shaped rectangle, whose length is the outer circumference of the microcrystalline ceramic outer layer body and whose width is the thickness of the microcrystalline ceramic outer layer body; then, a sand-planting area is selected as the first sand-planting area 107, and the cubic boron nitride abrasive 110 is implanted according to the abrasive arrangement path of the first sand-planting area 107; finally, the cubic boron nitride abrasive 110 is implanted in the second sand-planting area 108, the third sand-planting area 109, and the twelfth sand-planting area in a clockwise or counterclockwise direction according to the abrasive arrangement path of each sand-planting area.

[0064] The abrasive grain arrangement path of the first sand planting area 107 is as follows: the thickness direction of the microcrystalline ceramic outer layer green body is defined as the horizontal direction, and the outer circumferential direction is defined as the vertical direction. S1, starting from the left edge, the first row of abrasive grains is arranged horizontally until it reaches 2 / 3 of the thickness of the microcrystalline ceramic outer layer green body. The second row of abrasive grains is arranged horizontally from the middle position between the first abrasive grain and the second abrasive grain in the first row. The third row of abrasive grains is arranged horizontally from the middle position between the first abrasive grain and the second abrasive grain in the second row. And so on, until it reaches the right edge, which is the Nth row of abrasive grains. The number of abrasive grains in each row is the same, and the horizontal spacing between the centers of two adjacent abrasive grains in the same row is 210 μm. The vertical spacing between the centers of the abrasive grains in two adjacent rows is 210 μm; S2, starting from the right edge to the left edge, arrange the abrasive grains in the N+1th row horizontally from the middle position between the first abrasive grain and the second abrasive grain in the Nth row, and arrange the abrasive grains in the N+2th row horizontally from the middle position between the first abrasive grain and the second abrasive grain in the N+1th row, and so on, until the left edge is arranged. The number of abrasive grains in each row is the same, the horizontal spacing between the centers of two adjacent abrasive grains in the same row is 210 μm, and the vertical spacing between the centers of abrasive grains in two adjacent rows is 210 μm; S3, repeat path S1 to S2 until the abrasive grains in the first sand planting area are arranged.

[0065] The abrasive arrangement path of the second sand planting area 108 is: based on the abrasive arrangement path of the first sand planting area, the second row of abrasives are vertically translated to the first row, the third row of abrasives are vertically translated to the second row, and so on, until the abrasive arrangement of the second sand planting area is completed.

[0066] The abrasive arrangement path of the third sand planting area 109 is: based on the abrasive arrangement path of the second sand planting area, the second row of abrasives are vertically translated to the first row, the third row of abrasives are vertically translated to the second row, and so on, until the abrasive arrangement of the third sand planting area is completed.

[0067] This process is deduced by analogy until the abrasive grains in the twelfth sand planting area are arranged.

[0068] After the abrasive arrangement of the twelve sand-planting areas on the outer circumferential side of the outer layer of the microcrystalline ceramic blank is completed, it is placed in a sintering furnace for sintering. The sintering process is: heating from room temperature to 800°C at a rate of 8°C / min, and then heating from 800°C to 1000°C at a rate of 10°C / min, and then heating from 1000°C to 1200°C at a rate of 12°C / min, and then heating from 1200°C to 1600°C at a rate of 12°C / min, and then keeping warm for 4.5 hours. After the insulation is completed, cool from 1600°C to room temperature at a rate of 80°C / min. Argon protection is introduced during the entire sintering process.

[0069] In step one, laser drilling technology is used to evenly set twenty circulating cooling microchannels 105 inside the gradient porous energy consumption grinding wheel 1. The circulating cooling microchannels 105 pass through the inner layer 102 of the grinding wheel, the middle layer 103 of the grinding wheel and the outer layer 104 of the grinding wheel, wherein the part of the circulating cooling microchannel 105 located in the outer layer 104 of the grinding wheel is an S-shaped structure 106; the diameter of the circulating cooling microchannel 105 is 0.65 mm.

[0070] In step 2, the nanojet directional injection device 2 includes a porous ceramic nozzle 201 and a hydraulic pump 202. The porous ceramic nozzle 201 is connected to the hydraulic pump 202. The diameter of the porous ceramic nozzle 201 is 15 mm, and a plurality of injection holes are arranged on its outlet end face. The diameter of the injection hole is 0.2 mm, and the distance between the centers of two adjacent injection holes is 2 mm.

[0071] In step 2, the suction and chip removal device 3 includes a titanium alloy chip suction pipe 301 and a vacuum pump 302. The titanium alloy chip suction pipe 301 is connected to the vacuum pump 302. The diameter of the titanium alloy chip suction pipe 301 is 8 mm.

[0072] In steps 1 and 2, the circulating cooling microchannel 105 and the nanojet directional injection device 2 both use nano-cooling liquid, and the mass percentage of each substance in the nano-cooling liquid is 80wt% of base liquid, 10wt% of aluminum oxide, and 10wt% of graphene; the mass percentage of each substance in the base liquid is 70wt% of deionized water, 25wt% of ethylene glycol, and 5wt% of carboxymethyl cellulose; the particle size of the aluminum oxide is 45nm, and the thickness of the graphene layer is 4nm.

[0073] In step three, the multi-unit guide vane workpiece is ground according to the designed grinding process and grinding parameters, and goes through three processes of rough grinding, semi-finishing grinding and finishing grinding in sequence.

[0074] In the rough grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 100 m / s, the depth of a single grinding is 0.5 mm, and the machining allowance is 0.4 mm; a circulating cooling microchannel is used for primary cooling, and the applied pressure is 7 MPa.

[0075] In the semi-finishing grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 70m / s, the depth of single grinding is 0.15mm, and the machining allowance is 0.15mm; three-stage cooling is performed using a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device. The applied pressures of the circulating cooling microchannel and the nano-jet directional injection device are both 9MPa, and the applied pressure of the suction and chip removal device is 2.5MPa.

[0076] In the fine grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 40m / s, the depth of a single grinding is 0.04mm, and it is ground to the required size; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel is 9MPa, the applied pressure of the suction and chip removal device is 2.5MPa, and the nano-jet directional injection device performs intermittent spray cooling with an intermittent frequency of 1KHz and an applied pressure of 9MPa.

[0077] In this embodiment, the injection port of the circulating cooling microchannel 105, the injection port of the porous ceramic nozzle 201, and the chip suction port of the titanium alloy chip suction pipe 301 converge at the grinding arc area 5 of the multi-unit guide blade workpiece 4, forming a three-stage cooling mode.

[0078] In this embodiment, the grinding part of the multi-unit guide blade workpiece is the radial arc surface of the edge plate. The surface morphology of this part after grinding is as follows: Figure 9 As shown in the figure, it can be seen that after grinding, the surface of this part is smooth and there is no chatter mark.

[0079] In response to the technical bottlenecks faced by the existing technology, this embodiment innovatively proposes a "gradient porous energy-consuming grinding wheel + nano-directional cooling" synergistic system based on the anti-chatter grinding method of the gradient grinding wheel and nano-cooling multi-unit guide blades. This solution suppresses the chatter source through the damping characteristics of the gradient composite material, cutting off the vibration transmission path from the source, and then combines the directional penetration of the nano-coolant to achieve precise thermal control of the slit area, effectively solving the problem of the thermal-mechanical coupling effect of the multi-unit guide blades during the grinding process, and significantly improving the integrity of the workpiece processing surface.

[0080] Example 2:

[0081] According to another preferred embodiment of the present invention, the anti-chatter mark grinding method based on the gradient grinding wheel and nano-cooling multi-unit guide blade is basically the same as that of the first embodiment, with the following differences:

[0082] In step 1, the inner layer of the grinding wheel is prepared by laser additive manufacturing technology, with a laser power of 300 W, a scanning speed of 1200 mm / s, and a spot diameter of 70 μm.

[0083] The preparation method of the grinding wheel intermediate layer is as follows: first, a metal mold is designed according to the shape and size of the grinding wheel intermediate layer; then, stainless steel wires with a diameter of 0.1 mm are stacked in circles in the metal mold and pressed to obtain a stainless steel matrix, with the pressing temperature being 200° C., the pressure being 100 MPa, and the pressing time being 2 hours; finally, silicone rubber is heated to a fluid state and the fluid silicone rubber is injected into the stainless steel matrix to obtain the grinding wheel intermediate layer, with the injection temperature being 60° C., the injection pressure being 80 MPa, and the holding time being 40 minutes. The density of the composite material of stainless steel and silicone rubber is 3.5 g / cm 3 .

[0084] The preparation method of the outer layer of the grinding wheel is as follows: first, a microcrystalline ceramic outer layer blank is prepared by using laser additive manufacturing technology, with a laser power of 500W, a scanning speed of 1800mm / s, and a spot diameter of 90μm; then, cubic boron nitride abrasive grains are implanted onto the outer circumferential side of the microcrystalline ceramic outer layer blank according to a designed abrasive grain arrangement method by using electrostatic sand implantation technology; finally, the microcrystalline ceramic outer layer blank implanted with cubic boron nitride abrasive grains is placed in a sintering furnace for sintering to obtain the outer layer of the grinding wheel.

[0085] The mass percentages of each substance in the microcrystalline ceramic outer layer green body are 25wt% silicon dioxide, 65wt% aluminum oxide, and 10wt% yttrium oxide; a plurality of circular holes are evenly arranged on the outer circumferential side surface of the microcrystalline ceramic outer layer green body, the diameter of the circular holes is 50μm, the depth is 20μm, and the coverage rate of the plurality of circular holes on the outer circumferential side surface is 15%.

[0086] The median particle size of the cubic boron nitride abrasive grains is 80 μm. In the sand planting area, the lateral spacing between the centers of two adjacent abrasive grains in the same row is 120 μm, and the vertical spacing between the centers of abrasive grains in two adjacent rows is 120 μm.

[0087] After the abrasive grains in the twelve sand-planting areas on the outer circumferential side of the microcrystalline ceramic outer layer are arranged, they are placed in a sintering furnace for sintering. The sintering process is as follows: heating from room temperature to 800°C at a rate of 5°C / min, then from 800°C to 1000°C at a rate of 8°C / min, then from 1000°C to 1200°C at a rate of 10°C / min, then from 1200°C to 1600°C at a rate of 10°C / min, then holding for 4 hours. After the holding period, the temperature is lowered from 1600°C to room temperature at a rate of 50°C / min. Argon gas protection is introduced throughout the sintering process. The diameter of the circulating cooling microchannel is 0.5 mm.

[0088] In step 2, the diameter of the porous ceramic nozzle is 10 mm, and a plurality of injection holes are set on the outlet end face thereof. The diameter of the injection holes is 0.1 mm, and the distance between the centers of two adjacent injection holes is 2 mm. The diameter of the titanium alloy chip suction tube is 5 mm.

[0089] In steps 1 and 2, the mass percentages of the substances in the nano-cooling liquid are 75wt% base liquid, 15wt% aluminum oxide, and 10wt% graphene; the mass percentages of the substances in the base liquid are 68wt% deionized water, 27wt% ethylene glycol, and 5wt% carboxymethyl cellulose; the particle size of the aluminum oxide is 40nm, and the thickness of the graphene sheet is 3nm.

[0090] In step three, in the rough grinding process, the linear speed of the gradient porous energy consumption grinding wheel is 80 m / s, the depth of a single grinding is 0.4 mm, and the machining allowance is 0.3 mm; a circulating cooling microchannel is used for primary cooling, and the applied pressure is 6 MPa.

[0091] In the semi-finishing grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 60m / s, the depth of single grinding is 0.1mm, and the machining allowance is 0.1mm; three-stage cooling is performed using a circulating cooling microchannel, a nanojet directional injection device, and a suction and chip removal device. The applied pressures of the circulating cooling microchannel and the nanojet directional injection device are both 8MPa, and the applied pressure of the suction and chip removal device is 2MPa.

[0092] In the fine grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 30m / s, the depth of a single grinding is 0.03, and it is ground to the required size; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel is 8, the applied pressure of the suction and chip removal device is 2MPa, and the nano-jet directional injection device performs intermittent spray cooling with an intermittent frequency of 1KHz and an applied pressure of 8MPa.

[0093] Example 3:

[0094] According to another preferred embodiment of the present invention, the anti-chatter mark grinding method based on the gradient grinding wheel and nano-cooling multi-unit guide blade is basically the same as that of the first embodiment, with the following differences:

[0095] In step 1, the inner layer of the grinding wheel is prepared by laser additive manufacturing technology, with a laser power of 500 W, a scanning speed of 800 mm / s, and a spot diameter of 90 μm.

[0096] The preparation method of the grinding wheel intermediate layer is as follows: first, a metal mold is designed according to the shape and size of the grinding wheel intermediate layer; then, stainless steel wires with a diameter of 0.5 mm are stacked in circles in the metal mold and pressed to obtain a stainless steel matrix, with the pressing temperature at 220° C., the pressure at 150 MPa, and the pressing time at 1.5 hours; finally, silicone rubber is heated to a fluid state and the fluid silicone rubber is injected into the stainless steel matrix to obtain the grinding wheel intermediate layer, with the injection temperature at 70° C., the injection pressure at 120 MPa, and the holding time at 30 minutes. The density of the stainless steel and silicone rubber composite material is 4.5 g / cm 3 .

[0097] The preparation method of the outer layer of the grinding wheel is as follows: first, a microcrystalline ceramic outer layer blank is prepared by using laser additive manufacturing technology, with a laser power of 700W, a scanning speed of 1200mm / s, and a spot diameter of 120μm; then, cubic boron nitride abrasive grains are implanted onto the outer circumferential side of the microcrystalline ceramic outer layer blank according to a designed abrasive grain arrangement method by using electrostatic sand implantation technology; finally, the microcrystalline ceramic outer layer blank implanted with cubic boron nitride abrasive grains is placed in a sintering furnace for sintering to obtain the outer layer of the grinding wheel.

[0098] The mass percentages of each substance in the microcrystalline ceramic outer layer green body are 35wt% silicon dioxide, 55wt% aluminum oxide, and 10wt% yttrium oxide; a plurality of circular holes are evenly arranged on the outer circumferential side surface of the microcrystalline ceramic outer layer green body, the diameter of the circular holes is 55μm, the depth is 25μm, and the coverage rate of the plurality of circular holes on the outer circumferential side surface is 20%.

[0099] The median particle size of the cubic boron nitride abrasive grains is 120 μm. In the sand planting area, the lateral spacing between the centers of two adjacent abrasive grains in the same row is 300 μm, and the vertical spacing between the centers of abrasive grains in two adjacent rows is 300 μm.

[0100] After the abrasive grains in the twelve sand-planting areas on the outer circumferential side of the microcrystalline ceramic outer layer are arranged, they are placed in a sintering furnace for sintering. The sintering process is as follows: heating from room temperature to 800°C at a rate of 10°C / min, then from 800°C to 1000°C at a rate of 12°C / min, then from 1000°C to 1200°C at a rate of 15°C / min, then from 1200°C to 1600°C at a rate of 15°C / min, then holding for 5 hours. After the holding period, the temperature is lowered from 1600°C to room temperature at a rate of 100°C / min. Argon gas protection is introduced throughout the sintering process. The diameter of the circulating cooling microchannel is 0.8 mm.

[0101] In step 2, the diameter of the porous ceramic nozzle is 20 mm, and a plurality of injection holes are set on the outlet end face thereof. The diameter of the injection holes is 0.3 mm, and the distance between the centers of two adjacent injection holes is 2 mm. The diameter of the titanium alloy chip suction tube is 10 mm.

[0102] In steps 1 and 2, the mass percentages of the substances in the nano-cooling liquid are 85wt% of the base liquid, 5wt% of aluminum oxide, and 10wt% of graphene; the mass percentages of the substances in the base liquid are 73wt% of deionized water, 22wt% of ethylene glycol, and 5wt% of carboxymethyl cellulose; the particle size of the aluminum oxide is 50nm, and the thickness of the graphene sheet is 5nm.

[0103] In step three, in the rough grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 120 m / s, the depth of a single grinding is 0.6 mm, and the machining allowance is 0.5 mm; a circulating cooling microchannel is used for primary cooling, and the applied pressure is 8 MPa.

[0104] In the semi-finishing grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 80m / s, the depth of single grinding is 0.2mm, and the machining allowance is 0.2mm; three-stage cooling is performed using a circulating cooling microchannel, a nanojet directional injection device, and a suction and chip removal device. The applied pressures of the circulating cooling microchannel and the nanojet directional injection device are both 10MPa, and the applied pressure of the suction and chip removal device is 3MPa.

[0105] In the fine grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 50m / s, the depth of a single grinding is 0.05, and it is ground to the required size; a circulating cooling microchannel, a nanojet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel is 10, the applied pressure of the suction and chip removal device is 3MPa, and the nanojet directional injection device performs intermittent spray cooling with an intermittent frequency of 1KHz and an applied pressure of 10MPa.

[0106] Special Note: The technical solution of this invention involves numerous parameters, and the synergistic effects between these parameters must be comprehensively considered to achieve the beneficial effects and significant improvements of this invention. Furthermore, the value ranges of each parameter in the technical solution were obtained through extensive testing. The inventors have recorded extensive experimental data for each parameter and their combinations. Due to space limitations, the specific experimental data will not be disclosed here.

[0107] Those skilled in the art will readily understand that the present invention encompasses any combination of the components described in the Summary and Detailed Description of the Invention and the accompanying drawings. Due to space limitations and for the sake of clarity, not all of the various solutions resulting from these combinations are described. Any modifications, equivalent substitutions, and improvements within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for anti-chatter mark grinding of multi-unit guide blades based on a gradient grinding wheel and nano-cooling, characterized by: The grinding method comprises the following steps in order: Step 1: Design and prepare a gradient porous energy-consuming grinding wheel. According to the characteristics of the multi-unit guide blade machining surface, use a diamond roller to dress the gradient porous energy-consuming grinding wheel. Install the dressed gradient porous energy-consuming grinding wheel on the spindle of the grinding machine. Step 2: Clamp the multi-piece guide blade workpiece to be ground under the gradient porous energy consumption grinding wheel, and install the nano-jet directional injection device and the suction and chip removal device on one side of the multi-piece guide blade workpiece; Step 3: Start the grinding machine to rotate the gradient porous energy consumption grinding wheel, and simultaneously start the nano-jet directional injection device and the suction and chip removal device to grind the multi-unit guide blade workpiece according to the designed grinding process and grinding parameters; The gradient porous energy-consuming grinding wheel consists of three layers, which are, from the inside to the outside, an inner grinding wheel layer, a middle grinding wheel layer, and an outer grinding wheel layer; the inner grinding wheel layer, the middle grinding wheel layer, and the outer grinding wheel layer are independently prepared, and then the three layers are combined together, a silane coupling agent is coated between the outer grinding wheel layer and the middle grinding wheel layer, a metal transition layer is sprayed between the middle grinding wheel layer and the inner grinding wheel layer, and then hot isostatic pressing is used for compounding, the hot isostatic pressing temperatures of the outer grinding wheel layer, the middle grinding wheel layer, and the inner grinding wheel layer are 950° C., 200° C., and 600° C., respectively, the applied pressure is 150 MPa, the holding time is 120 min, and argon gas is introduced for protection; An axial hole is provided at the center of the gradient porous energy-consuming grinding wheel, and the axial hole, the grinding wheel inner layer, the grinding wheel middle layer and the grinding wheel outer layer are concentric circle structures; the width ratio of the grinding wheel inner layer, the grinding wheel middle layer and the grinding wheel outer layer is 1.5:1:2, the width of the grinding wheel inner layer is the difference between the radius of the grinding wheel inner layer and the radius of the axial hole, the width of the grinding wheel middle layer is the difference between the radius of the grinding wheel middle layer and the radius of the grinding wheel inner layer, and the width of the grinding wheel outer layer is the difference between the radius of the grinding wheel outer layer and the radius of the grinding wheel middle layer, and the thickness of the three layers is the same; The inner layer of the grinding wheel has a hexagonal honeycomb structure and is made of titanium alloy. The inner layer of the grinding wheel is made using laser additive manufacturing technology, with a laser power of 300-500W, a scanning speed of 800-1200mm / s, and a spot diameter of 70-90μm. The grinding wheel middle layer is made of a composite material of stainless steel and silicone. The preparation method comprises the following steps: first, designing a metal mold according to the shape and size of the grinding wheel middle layer; then, stacking stainless steel wires with a diameter of 0.1-0.5 mm in a circle in the metal mold and pressing to obtain a stainless steel matrix; the pressing temperature is 200-220° C., the pressure is 100-150 MPa, and the pressing time is 1.5-2 hours; finally, heating the silicone to a fluid state and injecting the fluid silicone into the stainless steel matrix to obtain the grinding wheel middle layer; the injection temperature is 60-70° C., the injection pressure is 80-120 MPa, and the pressure holding time is 30-40 minutes. The density of the stainless steel and silicone composite material is 3.5-4.5 g / cm 3 ; The outer layer of the grinding wheel is a composite structure formed by a microcrystalline ceramic outer layer body and cubic boron nitride abrasive grains. The preparation method is as follows: first, the microcrystalline ceramic outer layer body is prepared by laser additive manufacturing technology, with a laser power of 500-700W, a scanning speed of 1200-1800mm / s, and a spot diameter of 90-120μm; then, the cubic boron nitride abrasive grains are implanted on the outer circumferential side of the microcrystalline ceramic outer layer body according to a designed abrasive grain arrangement method by electrostatic sand implantation technology; finally, the microcrystalline ceramic outer layer body implanted with the cubic boron nitride abrasive grains is placed in a sintering furnace for sintering to obtain the outer layer of the grinding wheel; The mass percentages of various substances in the microcrystalline ceramic outer layer body are 25-35wt% of silicon dioxide, 55-65wt% of aluminum oxide, and 5-15wt% of yttrium oxide; a plurality of circular holes are evenly arranged on the outer circumferential side surface of the microcrystalline ceramic outer layer body, the diameter of the circular holes is 50-55μm, the depth is 20-25μm, and the coverage rate of the plurality of circular holes on the outer circumferential side surface is 15-20%.

2. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 1 is characterized in that: The median particle size of the cubic boron nitride abrasive is 80-120 μm, and the abrasive arrangement method is as follows: first, the outer circumferential side surface of the microcrystalline ceramic outer layer body is evenly divided into twelve sand-planting areas. If the outer circumferential side surface of the microcrystalline ceramic outer layer body is unfolded, it becomes a strip-shaped rectangle, whose length is the outer circumference of the microcrystalline ceramic outer layer body and whose width is the thickness of the microcrystalline ceramic outer layer body; then, a sand-planting area is selected as the first sand-planting area, and cubic boron nitride abrasive is implanted according to the abrasive arrangement path of the first sand-planting area; finally, cubic boron nitride abrasive is implanted in the second sand-planting area, the third sand-planting area, and the twelfth sand-planting area in a clockwise or counterclockwise direction according to the abrasive arrangement path of each sand-planting area; The abrasive arrangement path of the first sand planting area is as follows: the thickness direction of the microcrystalline ceramic outer layer body is defined as the horizontal direction, and the outer circumferential direction is defined as the vertical direction. S1, starting from the left edge, the first row of abrasive grains is arranged horizontally until it is arranged to 2 / 3 of the thickness of the microcrystalline ceramic outer layer body, and the second row of abrasive grains is arranged horizontally from the middle position of the first abrasive grain and the second abrasive grain in the first row, and the third row of abrasive grains is arranged horizontally from the middle position of the first abrasive grain and the second abrasive grain in the second row, and so on, until it is arranged to the right edge, which is the Nth row of abrasive grains. The number of abrasive grains in each row is the same, and the lateral spacing between the centers of two adjacent abrasive grains in the same row is 120-300 μm. The abrasive grains in two adjacent rows are arranged horizontally. The vertical spacing between the centers of the particles is 120-300 μm; S2, starting from the right edge to the left edge, starting from the middle position between the first abrasive particle and the second abrasive particle in the Nth row, the abrasive particles in the N+1th row are arranged horizontally, starting from the middle position between the first abrasive particle and the second abrasive particle in the N+1th row, the abrasive particles in the N+2th row are arranged horizontally, and so on, until the left edge is arranged, the number of abrasive particles in each row is the same, the horizontal spacing between the centers of two adjacent abrasive particles in the same row is 120-300 μm, and the vertical spacing between the centers of abrasive particles in two adjacent rows is 120-300 μm; S3, repeating the paths S1 to S2 until the abrasive particles in the first sand planting area are arranged; The abrasive arrangement path of the second sand planting area is as follows: based on the abrasive arrangement path of the first sand planting area, the abrasives in the second row are vertically translated to the first row, and the abrasives in the third row are vertically translated to the second row, and so on, until the abrasives in the second sand planting area are completely arranged; The abrasive arrangement path of the third sand planting area is as follows: based on the abrasive arrangement path of the second sand planting area, the abrasives in the second row are vertically translated to the first row, and the abrasives in the third row are vertically translated to the second row, and so on, until the abrasives in the third sand planting area are completely arranged; This process is repeated until the abrasive grains in the twelfth sand planting area are arranged. After the abrasive arrangement of the twelve sand-planting areas on the outer circumferential side of the outer layer of the microcrystalline ceramic blank is completed, it is placed in a sintering furnace for sintering. The sintering process is to increase the temperature from room temperature to 800°C at a heating rate of 5-10°C / min, and then continue to increase the temperature from 800°C to 1000°C at a heating rate of 8-12°C / min, and then continue to increase the temperature from 1000°C to 1200°C at a heating rate of 10-15°C / min, and then continue to increase the temperature from 1200°C to 1600°C at a heating rate of 10-15°C / min, and then keep warm for 4-5 hours. After the insulation is completed, cool it from 1600°C to room temperature at a cooling rate of 50-100°C / min. Argon protection is introduced during the entire sintering process.

3. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 2 is characterized in that: In step one, laser drilling technology is used to evenly set twenty circulating cooling microchannels inside the gradient porous energy consumption grinding wheel. The circulating cooling microchannels penetrate the inner layer, the middle layer and the outer layer of the grinding wheel, wherein the part of the circulating cooling microchannel located in the outer layer of the grinding wheel is an S-shaped structure; the diameter of the circulating cooling microchannel is 0.5-0.8 mm.

4. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 3 is characterized in that: In step 2, the nanojet directional injection device includes a porous ceramic nozzle and a hydraulic pump. The porous ceramic nozzle is connected to the hydraulic pump. The diameter of the porous ceramic nozzle is 10-20 mm. A plurality of injection holes are arranged on the outlet end face thereof. The diameter of the injection holes is 0.1-0.3 mm, and the distance between the centers of two adjacent injection holes is 2 mm.

5. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 4 is characterized in that: In step 2, the suction and chip removal device includes a titanium alloy chip suction tube and a vacuum pump. The titanium alloy chip suction tube is connected to the vacuum pump, and the diameter of the titanium alloy chip suction tube is 5-10 mm.

6. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 5 is characterized in that: In steps 1 and 2, the circulating cooling microchannel and the nano-jet directional injection device both use nano-cooling liquid, and the mass percentage of each substance in the nano-cooling liquid is 75-85wt% of base liquid, 5-15wt% of aluminum oxide, and 5-15wt% of graphene; the mass percentage of each substance in the base liquid is 68-73wt% of deionized water, 22-27wt% of ethylene glycol, and 4-6wt% of carboxymethyl cellulose; the particle size of the aluminum oxide is 40-50nm, and the thickness of the graphene layer is 3-5nm.

7. The anti-chatter mark grinding method of multi-unit guide blades based on gradient grinding wheel and nano-cooling according to claim 6 is characterized in that: In step three, the multi-unit guide vane workpiece is ground according to the designed grinding process and grinding parameters, and the three processes of rough grinding, semi-finishing grinding and finishing grinding are carried out in sequence; In the rough grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 80-120 m / s, the single grinding depth is 0.4-0.6 mm, and the machining allowance is 0.3-0.5 mm; a circulating cooling microchannel is used for primary cooling, and the applied pressure is 6-8 MPa; In the semi-finishing process, the linear speed of the gradient porous energy-consuming grinding wheel is 60-80m / s, the single grinding depth is 0.1-0.2mm, and the machining allowance is 0.1-0.2mm; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel and the nano-jet directional injection device is 8-10MPa, and the applied pressure of the suction and chip removal device is 2-3MPa. In the fine grinding process, the linear speed of the gradient porous energy-consuming grinding wheel is 30-50m / s, the depth of a single grinding is 0.03-0.05mm, and it is ground to the required size; a circulating cooling microchannel, a nano-jet directional injection device, and a suction and chip removal device are used for three-stage cooling. The applied pressure of the circulating cooling microchannel is 8-10MPa, the applied pressure of the suction and chip removal device is 2-3MPa, and the nano-jet directional injection device performs intermittent spray cooling with an intermittent frequency of 1KHz and an applied pressure of 8-10MPa.

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