A segmented bonded grinding wheel and its manufacturing method

Abstract

This invention discloses a segmented bonded grinding wheel and its manufacturing method, belonging to the field of machining abrasive manufacturing technology. The grinding wheel includes at least two axially segmented substrates, annular grooves, a positioning hole system, and a bonding layer. The manufacturing method is achieved through segmented substrate prefabrication, mating surface processing, positioning assembly, axial pressure bonding, and post-processing. This invention avoids weakening of the grinding layer strength by integrally molding the axially segmented substrates, adapts the annular grooves to different grinding scenarios, improves assembly efficiency through graded design of positioning holes, and enables simultaneous production of multiple sets through axial pressure bonding. It solves the problems of weak strength, poor cooling, difficult positioning, and low efficiency of traditional grinding wheels, and is suitable for high-speed precision grinding.

Description

Technical Field

[0001] This invention belongs to the field of machining abrasive manufacturing technology, specifically relating to a segmented bonding grinding wheel and its manufacturing method, which forms an annular groove through axial segmented prefabrication, groove matching and docking, and precision bonding. Background Technology

[0002] In the grinding of precision parts such as bearings and gears, grinding wheels with annular grooves are key tools for achieving efficient cooling and chip removal. Existing technologies have the following drawbacks: Mechanical grooving method: Grooving is carried out on the integral sintered grinding wheel blank with diamond rollers. It has problems such as low efficiency (grooving time accounts for more than 30% of the manufacturing cycle), material waste (removal of effective abrasive), weakening strength (micro-cracks are easily generated at the bottom of the groove), and poor groove accuracy (affected by tool wear, low batch consistency). Integral molding method: The mold pre-sets the core and directly forms the groove, but it has problems such as molding difficulties (uneven abrasive filling in the narrow groove area), easy demolding damage (the blank and the core are tightly engaged and easy to crack), and poor mold versatility (each groove type requires a customized mold); Ordinary segmented grinding wheels: As shown in the patented segmented grinding wheel and its manufacturing method (publication number CN101341004B), they mostly adopt circumferential segmentation (split along the circumference) and are not designed for axial splicing. They cannot achieve precise forming of the groove on the working surface, nor can they adapt to the groove manufacturing requirements of axial segmentation. Cooling efficiency bottleneck: Traditional vertical grooves (straight grooves) only provide radial coolant flow. When the grinding wheel rotates at high speed, the coolant is difficult to penetrate into the grinding arc area due to the "air barrier" effect, which often leads to workpiece burns and grinding debris accumulation. Summary of the Invention

[0003] This invention provides a segmented bonded grinding wheel and its manufacturing method. Through the synergistic innovation of "axial segmented matrix integral molding", "multi-groove annular groove" and "center / intermediate positioning hole graded positioning", it solves the problems of weak strength, poor cooling and difficult positioning in traditional processes, and realizes the manufacturing of grinding wheels with no mechanical damage, high precision and continuous grinding.

[0004] This invention provides the following technical solution: A segmented adhesive grinding wheel, characterized in that it comprises: At least two axially segmented substrates are spliced ​​along the axis of the grinding wheel. Each segmented substrate is an integrally formed structure, comprising a grinding layer on the outer side and a substrate layer on the inner side of the grinding layer. The grinding layer is composed of superhard abrasive grains bonded by a ceramic binder, with a density of not less than 2.2 g / cm³ and a porosity of 15% to 25%. The substrate layer is a support structure and is integrally sintered with the grinding layer. An annular groove is formed by the gap between the grinding layers of two adjacent segmented substrates and the thickness of the bonding layer at the mating surface of the substrate layers. The groove shape can be planar, stepped, or inclined, wherein: the groove wall of a planar groove is perpendicular to the grinding wheel axis; the groove wall of a stepped groove has steps perpendicular to the groove wall; the angle between the groove wall and the grinding wheel axis of an inclined groove is 10° to 30°; the groove width is equal to the sum of the gap between the grinding layers of adjacent segmented substrates and the thickness of the bonding layer, and the groove depth is equal to the thickness of the grinding layer. The adhesive layer, located between the mating surfaces of the substrate layers of two adjacent segmented substrates, is made of modified epoxy resin, with a thickness of 0.05mm to 0.2mm, a tensile strength of not less than 30MPa, and a temperature resistance of not less than 200℃. Positioning hole system, including: The central positioning hole is vertically opened at one end of the segmented substrate layer, located at the central axis position, and does not penetrate the substrate layer; The central positioning hole is vertically opened at the other end of the segmented substrate layer, located at a position not on the central axis. The central positioning hole is used to cooperate with the positioning fixture to achieve axial positioning, and the intermediate positioning hole is used to insert a positioning post between two adjacent segmented substrates to achieve rapid central positioning.

[0005] Its technical advantages lie in the fact that by integrally molding the axially segmented substrate (grinding layer and substrate layer), it avoids the weak connection points between the grinding layer and the substrate layer in a split structure. The annular groove is formed by the gap between the grinding layers and the thickness of the bonding layer, and the groove depth is equal to the thickness of the grinding layer. This ensures that the groove is completely located within the high-strength grinding layer, avoiding strength redundancy caused by the substrate layer participating in the groove depth definition. Furthermore, the multi-groove design (planar / stepped / skewed) adapts to different grinding scenarios. The planar type is suitable for surface grinding, the stepped type is suitable for heavy-duty grinding, and the skewed type (10°-30°) is suitable for other grinding scenarios. The high-speed rotation of the centrifugal force of the grinding wheel (° angle) generates a circumferential spiral driving force for the coolant, breaking through the "air film barrier" on the surface of the grinding wheel. This greatly reduces the grinding temperature and the amount of grinding debris residue, preventing workpiece burns and grinding wheel blockage. The positioning hole system (center positioning hole and intermediate positioning hole) achieves graded positioning: the center positioning hole abuts against the gravity plate / platform positioning group, serving as an axial reference to prevent the grinding layer from being weakened by the positioning hole; the intermediate positioning hole (at the other end of the substrate layer, not at the center axis position) is used to insert a positioning post, achieving rapid center positioning of adjacent substrate segments, which can also greatly improve assembly efficiency.

[0006] Preferably, the superhard abrasive grains are cubic boron nitride or diamond, and the material of the substrate layer is consistent with the ceramic binder of the grinding layer.

[0007] Its technical advantages lie in the fact that the superhard abrasive grains are limited to cubic boron nitride (CBN) or diamond, with hardnesses of HV8000-10000 and HV10000 and above, respectively, making them suitable for precision grinding of high-hardness materials (such as bearing steel and cemented carbide). The substrate material is consistent with the ceramic binder of the grinding layer, avoiding the risk of sintering cracking caused by the difference in thermal expansion coefficients of different materials, ensuring the structural stability when the segmented substrate is integrally formed, and the flexural strength after sintering is not less than 50MPa.

[0008] Preferably, the outer circular surface of the grinding layer is continuous and uninterrupted, and it comes into direct contact with the workpiece being ground during grinding.

[0009] Its technical effect is that the outer circular surface of the grinding layer is continuous and uninterrupted, and the continuous grinding surface also reduces grinding impact, thereby reducing the surface roughness Ra of the workpiece.

[0010] Preferably, the width accuracy of the annular groove is ±0.05mm, and the depth accuracy is ±0.1mm.

[0011] Its technical advantages lie in limiting the width accuracy of the annular groove to ±0.05mm and the depth accuracy to ±0.1mm. Through precision grinding of the segmented substrate mating surfaces (flatness ≤0.02mm) and strict control of the adhesive layer thickness (0.05-0.2mm), the consistency of the groove dimensions is ensured. In batch production, the annular groove accuracy fluctuation is ≤±0.02mm, avoiding the groove deviation (above ±0.2mm) caused by tool wear in traditional mechanical grooving. It is suitable for the dimensional accuracy requirements of precision grinding (such as bearing ring groove grinding tolerance ≤0.005mm).

[0012] A method for manufacturing a segmented bonded grinding wheel, used to manufacture the above-mentioned segmented bonded grinding wheel, includes the following steps: S1 Segmented Substrate Prefabrication: The ceramic binder and superhard abrasive grains are pressed into shape using a hot pressing process, and then sintered at high temperature to form an integral segmented substrate containing a grinding layer and a substrate layer; a central positioning hole is provided at one end of the substrate layer, and an intermediate positioning hole is provided at the other end; none of the positioning holes penetrate the substrate layer. S2 mating surface processing: The mating surfaces of the segmented substrate layers are finely ground or polished to ensure that the flatness does not exceed 0.02mm and the surface roughness Ra does not exceed 3.2μm. Subsequently, the substrate layer is ultrasonically cleaned and activated to enhance the bonding force. S3 Positioning Assembly: Multiple segmented substrates are quickly centered by inserting positioning pins through the middle positioning holes; the center positioning hole of the top segmented substrate abuts against the gravity plate, and the center positioning hole of the bottom segmented substrate abuts against the platform positioning group. An annular groove is formed between two adjacent segments of substrates, and spacers are used between the annular grooves to control the gap between the grinding layers of adjacent segments of substrates. S4 Axial Pressure Bonding: The gravity plate and platform are distributed in parallel and connected by telescopic struts. Modified epoxy resin is applied to the mating surface of the substrate layer. Then the gravity plate is released, so that the gravity plate applies pressure to the segmented substrate along the axial direction by its own weight. Multiple sets of grinding wheels can be bonded simultaneously between the gravity plate and the platform. Then the gravity plate, platform and grinding wheels are transferred to a constant temperature oven for curing to form a strong adhesive layer. The thickness of the adhesive layer and the gap reserved on the inner side of the grinding layer of the adjacent two segmented substrates together form the annular groove on the working surface of the grinding wheel. S5 Post-treatment: After curing, remove the spacers and gravity plates, and perform static balance verification on the grinding wheel to ensure that the imbalance does not exceed 5 g·cm; perform fine grinding on the outer cylindrical surface of the grinding layer to ensure that the surface roughness Ra does not exceed 0.8 μm.

[0013] Its technical advantages lie in the fact that, through the prefabrication of the S1 segmented substrate (integrated molding by hot pressing and high-temperature sintering) and the hierarchical design of the positioning holes (axial reference of the central positioning hole and rapid positioning of the intermediate positioning holes), the problems of "slow positioning and poor coaxiality" of traditional segmented grinding wheels are solved. In the S3 positioning assembly, "the central positioning hole at the top / bottom end abuts against the gravity plate / platform", combined with the concentric positioning fixture, to ensure the coaxiality of the segmented substrate. The S4 axial pressure bonding adopts "gravity plate self-weight pressure and multiple sets of synchronous bonding", and by utilizing the parallel distribution of the gravity plate and platform and the connection of telescopic struts, multiple sets of grinding wheels can be bonded at the same time to improve production efficiency. The partition block is used as a temporary positioning tool, which is removed after bonding and curing without affecting the function of the annular groove, and the material utilization rate is 100% (no material waste from mechanical grooving).

[0014] Preferably, the hot pressing process parameters in step S1 are: temperature 800℃ to 1200℃, pressure 5MPa to 20MPa; the high-temperature sintering temperature is 1000℃ to 1300℃, and the flexural strength of the sintered segmented matrix is ​​not less than 50MPa.

[0015] Its technical advantages lie in limiting the hot pressing process parameters (800-1200℃, 5-20MPa) and the high-temperature sintering temperature (1000-1300℃) to ensure the full reaction between the ceramic binder and the superhard abrasive grains. The hot pressing pressure makes the abrasive grains evenly distributed and avoids agglomeration. The sintering temperature makes the binder vitrify and form a dense structure (grinding layer density ≥2.2g / cm³).

[0016] Preferably, the spacer in step S3 is a detachable rigid block with a thickness equal to the target annular groove gap, made of metal or ceramic, and removed after bonding and curing.

[0017] The technical advantage lies in the fact that the spacer (made of metal / ceramic material, with a thickness equal to the target annular groove gap) serves as a temporary positioning tool, ensuring uniform gap between grinding layers (groove width accuracy ±0.05mm). After bonding and curing, it can be removed without affecting the cooling / chip removal function of the annular groove.

[0018] Preferably, the positioning fixture is a concentric positioning and axial pressure fixture, comprising the platform, positioning group, gravity plate, and telescopic support rod; the positioning group is fixedly connected to the platform and is used to support and position the center positioning holes of the bottommost and topmost segment bases; the gravity plate is connected to the telescopic support rod and is used to abut against the center positioning hole of the topmost segment base and apply axial pressure to ensure that the coaxiality of the segment bases does not exceed 0.01mm; the telescopic support rod is used to adjust the distance between the gravity plate and the platform to accommodate different numbers of segment bases.

[0019] Its technical advantages lie in clearly defining the positioning fixture structure (platform, positioning group, gravity plate, telescopic support rod) and positioning logic (the top center positioning hole abuts against the gravity plate, and the bottom end abuts against the platform positioning group), ensuring the coaxiality of the segmented substrate is ≤0.01mm through "bidirectional axial positioning". This fixture design ensures that the parallelism error between the gravity plate and the platform is ≤0.005mm, the axial pressure uniformity is ≥95%, and avoids excessive dynamic balance of the grinding wheel caused by uneven bonding layer thickness (unbalance >5g·cm).

[0020] Preferably, the curing conditions for the adhesive layer in step S4 are: temperature 80°C to 120°C, time 2 hours to 4 hours, and the thickness uniformity error of the cured adhesive layer does not exceed 0.02 mm.

[0021] The technical advantage lies in limiting the curing conditions of the adhesive layer (80-120℃, 2-4h), ensuring full cross-linking of the modified epoxy resin adhesive. Too low a temperature (<80℃) will result in incomplete curing and a tensile strength <20MPa; too high a temperature (>120℃) will cause the adhesive layer to crack. The adhesive layer cured under these conditions has a thickness uniformity error ≤0.02mm, a tensile strength ≥30MPa, and a temperature resistance ≥200℃, meeting the thermal stability requirements during high-speed grinding (≥3000r / min).

[0022] Preferably, the static balance verification in step S5 is performed using a dynamic balancing machine, and the circular runout of the outer surface of the finely ground layer does not exceed 0.01 mm.

[0023] Its technical advantages are as follows: static balance calibration (dynamic balancing machine) ensures that the unbalance of the grinding wheel is ≤5g·cm, avoiding vibration during high-speed rotation (vibration amplitude <0.005mm), and the roundness error of the workpiece is ≤0.002mm; the fine grinding of the outer cylindrical surface of the grinding layer (Ra≤0.8μm) makes the circular runout of the grinding surface ≤0.01mm, which solves the problem of the flatness deviation of the outer cylindrical surface (≤0.02mm) after the sintering of the segmented substrate, and ensures that the surface roughness of the workpiece is stable at Ra0.6-0.8μm during grinding, meeting the grinding requirements of precision parts (such as aero-engine blades).

[0024] The beneficial effects of this invention are: 1: The axial segmented substrate adopts the integral sintering of the grinding layer and the substrate layer, which avoids the weak connection between the grinding layer and the substrate layer in the traditional split structure. At the same time, since the outer circular surface of the grinding layer is continuous and uninterrupted, the grinding impact caused by the interruption is reduced, thereby reducing the surface roughness Ra of the ground workpiece.

[0025] 2: The annular groove adopts a multi-groove design with flat, stepped, and inclined groove types. The flat groove wall is perpendicular to the axis and is suitable for surface grinding. The stepped groove bottom has a step and is suitable for heavy-duty grinding (such as rough grinding of gear teeth). The inclined groove wall has an angle of 10°-30° with the axis. It uses the centrifugal force of high-speed rotation (≥3000r / min) to make the coolant generate a circumferential spiral driving force, which breaks through the "air film barrier" on the surface of the grinding wheel. This can greatly reduce the grinding temperature and the amount of grinding debris residue, and avoid workpiece burning and grinding wheel clogging.

[0026] 3. The positioning hole system adopts a hierarchical design: the central positioning hole abuts against the gravity plate / platform positioning group, serving as an axial reference to prevent the grinding layer from being weakened by the positioning hole; the middle positioning hole is inserted into the positioning post, realizing rapid center positioning of adjacent segmented substrates, which can also greatly improve assembly efficiency.

[0027] 4: Axial pressure bonding adopts the design of "gravity plate self-weight pressure and multiple sets of synchronous bonding". The gravity plate is connected to the platform through telescopic support rods, which can bond multiple sets of grinding wheels at the same time to improve production efficiency. The partition block is used as a temporary positioning tool. It can be removed after bonding and curing without affecting the function of the annular groove. The material utilization rate is 100% (no material waste from mechanical grooving).

[0028] 5: The annular groove width accuracy is ±0.05mm and the groove depth accuracy is ±0.1mm. This is achieved through precision grinding of the segmented substrate mating surfaces (flatness ≤0.02mm) and strict control of the adhesive layer thickness (0.05-0.2mm). In batch production, the annular groove accuracy fluctuation is ≤±0.02mm, which is suitable for the dimensional accuracy requirements of precision grinding (such as bearing ring groove grinding tolerance ≤0.005mm). Attached Figure Description

[0029] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a diagram illustrating the effect of the clamping and positioning function of this invention. Figure 2 This is a diagram illustrating the bonding effect of the present invention; Figure 3 This is a schematic diagram of a planar annular groove structure between grinding layers; Figure 4 This is a schematic diagram of a stepped annular groove structure between grinding layers; Figure 5 This is a schematic diagram of an annular groove structure with inclined grooves between grinding layers; Markings in the diagram: 1. Gravity plate; 2. Platform; 3. Telescopic strut; 4. Spacer; 5. Grinding layer; 6. Substrate layer; 7. Annular groove; 8. Center positioning hole. Detailed Implementation

[0030] Example 1 like Figure 1-5 As shown, a segmented adhesive grinding wheel, in this embodiment, includes: At least two axially segmented substrates are spliced ​​along the axis of the grinding wheel. Each segmented substrate is an integrally formed structure, including a grinding layer 5 on the outer side and a substrate layer 6 on the inner side of the grinding layer 5. The grinding layer 5 is composed of superhard abrasive grains bonded by a ceramic binder, with a density of not less than 2.2 g / cm³ and a porosity of 15% to 25%. The substrate layer 6 is a support structure and is integrally sintered with the grinding layer 5. The annular groove 7 is formed by the gap between the grinding layers 5 of two adjacent segmented substrates and the thickness of the bonding layer at the mating surface of the substrate layer 6. The groove shape of the annular groove 7 can be planar, stepped, or inclined, wherein: the groove wall of the planar groove is perpendicular to the grinding wheel axis; the groove wall of the stepped groove has a step perpendicular to the groove wall; the angle between the groove wall of the inclined groove and the grinding wheel axis is 10° to 30°; the groove width of the annular groove 7 is equal to the sum of the gap between the grinding layers 5 of adjacent segmented substrates and the thickness of the bonding layer, and the groove depth is equal to the thickness of the grinding layer 5. The adhesive layer, located between the mating surfaces of the substrate layers 6 of two adjacent segmented substrates, is made of modified epoxy resin, with a thickness of 0.05mm to 0.2mm, a tensile strength of not less than 30MPa, and a temperature resistance of not less than 200℃. Positioning hole system, including: The central positioning hole 8 is vertically opened at one end of the segmented substrate layer 6, located at the central axis position, and does not penetrate the substrate layer 6; The central positioning hole is vertically opened at the other end of the segmented substrate layer 6, located at a position not on the central axis. The central positioning hole 8 is used to cooperate with the positioning fixture to achieve axial positioning, and the intermediate positioning hole is used to insert a positioning post between two adjacent segmented substrates to achieve rapid central positioning.

[0031] Thus, by integrally molding the axially segmented substrate (grinding layer 5 and substrate layer 6), the weak connection points between grinding layer 5 and substrate layer 6 in the split structure are avoided. The annular groove 7 is formed by the gap of grinding layer 5 and the thickness of the bonding layer, and the groove depth is equal to the thickness of grinding layer 5. This ensures that the groove is completely located within the high-strength grinding layer 5, avoiding strength redundancy caused by the substrate layer 6 participating in the groove depth definition. Furthermore, the multi-groove design (planar / stepped / skewed) adapts to different grinding scenarios. The planar type is suitable for surface grinding, the stepped type is suitable for heavy-duty grinding, and the skewed type (10°-30°) is suitable for other grinding scenarios. The included angle utilizes the centrifugal force of high-speed rotation to generate a circumferential spiral driving force for the coolant, breaking through the "air film barrier" on the surface of the grinding wheel. This can greatly reduce the grinding temperature and the amount of grinding debris residue, avoiding workpiece burns and grinding wheel blockage. The positioning hole system (center positioning hole 8 and intermediate positioning hole) achieves graded positioning: the center positioning hole 8 abuts against the positioning group of gravity plate 1 / platform 2, serving as an axial reference to prevent the grinding layer 5 from being weakened by the positioning hole; the intermediate positioning hole (the other end of the substrate layer 6, at a position not on the central axis) is used to insert a positioning post, achieving rapid center positioning of adjacent segmented substrates, which can also greatly improve assembly efficiency.

[0032] The superhard abrasive grains are cubic boron nitride or diamond, and the material of the substrate layer 6 is the same as the ceramic binder of the grinding layer 5.

[0033] Therefore, the superhard abrasive grains are limited to cubic boron nitride (CBN) or diamond, with hardnesses of HV8000-10000 and HV10000 and above, respectively, which are suitable for precision grinding of high-hardness materials (such as bearing steel and cemented carbide). The substrate layer 6 has the same material and ceramic binder as the grinding layer 5, which avoids the risk of sintering cracking caused by the difference in thermal expansion coefficients of different materials, ensures the structural stability when the segmented substrate is integrally formed, and the flexural strength after sintering is not less than 50MPa.

[0034] The outer circular surface of the grinding layer 5 is continuous and uninterrupted, and it comes into direct contact with the workpiece being ground during grinding.

[0035] Its technical effect is that the outer surface of the grinding layer 5 is continuous and uninterrupted, and the continuous grinding surface also reduces grinding impact, thereby reducing the surface roughness Ra of the workpiece.

[0036] The width accuracy of the annular groove 7 is ±0.05mm, and the depth accuracy is ±0.1mm.

[0037] Thus, the width accuracy of the annular groove 7 is limited to ±0.05mm and the depth accuracy to ±0.1mm. Through the fine grinding of the segmented substrate mating surface (flatness ≤0.02mm) and the strict control of the adhesive layer thickness (0.05-0.2mm), the consistency of the groove dimensions is ensured. In batch production, the accuracy fluctuation of the annular groove 7 is ≤±0.02mm, avoiding the groove shape deviation (above ±0.2mm) caused by tool wear in traditional mechanical grooving. It is suitable for the dimensional accuracy requirements of precision grinding (such as bearing ring groove grinding tolerance ≤0.005mm).

[0038] A method for manufacturing a segmented bonded grinding wheel, used to manufacture the above-mentioned segmented bonded grinding wheel, includes the following steps: S1 Segmented Substrate Prefabrication: The ceramic binder and superhard abrasive grains are pressed into shape using a hot pressing process, and then sintered at high temperature to form an integral segmented substrate containing a grinding layer 5 and a substrate layer 6; one end of the substrate layer 6 has a central positioning hole 8, and the other end has an intermediate positioning hole, and none of the positioning holes penetrate the substrate layer 6. S2 mating surface processing: The mating surface of the substrate layer 6 of the segmented substrate is finely ground or polished to ensure that the flatness does not exceed 0.02mm and the surface roughness Ra does not exceed 3.2μm. Then, the substrate layer 6 is ultrasonically cleaned and activated to enhance the bonding force. S3 Positioning Assembly: Multiple segmented bases are quickly centered by inserting positioning posts through the middle positioning holes; the center positioning hole 8 of the top segmented base abuts against the gravity plate 1, and the center positioning hole 8 of the bottom segmented base abuts against the positioning group of the platform 2. An annular groove 7 is formed between two adjacent groups of segmented bases, and spacers 4 are used to separate the annular groove 7. S4 Axial pressure bonding: Gravity plate 1 and platform 2 are distributed in parallel and connected by telescopic struts 3. Modified epoxy resin is applied to the mating surface of the substrate layer 6. Then, gravity plate 1 is released, so that gravity plate 1 applies pressure to the segmented substrate along the axial direction by its own weight. Multiple sets of grinding wheels can be bonded simultaneously between gravity plate 1 and platform 2. Then, gravity plate 1, platform 2 and grinding wheels are transferred to a constant temperature oven for curing to form a strong adhesive layer. The thickness of this adhesive layer and the gap reserved on the inner side of the grinding layer 5 of the adjacent two segmented substrates together form the annular groove 7 on the working surface of the grinding wheel. S5 Post-treatment: After curing, remove the spacer 4 and gravity plate 1, perform static balance check on the grinding wheel to ensure that the imbalance does not exceed 5g·cm; perform fine grinding on the outer circular surface of the grinding layer 5 to ensure that the surface roughness Ra does not exceed 0.8μm.

[0039] By using the S1 segmented substrate prefabrication (hot pressing and high-temperature sintering integral molding) and the hierarchical design of positioning holes (axial reference of the central positioning hole 8 and rapid positioning of the intermediate positioning holes), the problems of "slow positioning and poor coaxiality" of traditional segmented grinding wheels are solved. In the S3 positioning assembly, "the central positioning hole 8 at the top / bottom end abuts against the gravity plate 1 / platform 2", combined with the concentric positioning fixture, to ensure the coaxiality of the segmented substrate. The S4 axial pressure bonding adopts "gravity plate 1 self-weight pressure and multiple sets of synchronous bonding", and utilizes the parallel distribution of gravity plate 1 and platform 2 and the connection of telescopic support rod 3 to bond multiple sets of grinding wheels at the same time to improve production efficiency. The partition block 4 is used as a temporary positioning tool, which is removed after bonding and curing without affecting the function of the annular groove 7, and the material utilization rate is 100% (no material waste from mechanical grooving).

[0040] The hot pressing process parameters in step S1 are: temperature 800℃ to 1200℃, pressure 5MPa to 20MPa; the high-temperature sintering temperature is 1000℃ to 1300℃, and the flexural strength of the sintered segmented matrix is ​​not less than 50MPa.

[0041] Therefore, the hot pressing process parameters (800-1200℃, 5-20MPa) and high-temperature sintering temperature (1000-1300℃) are limited to ensure the full reaction between the ceramic binder and the superhard abrasive grains. The hot pressing pressure ensures that the abrasive grains are evenly distributed and avoids agglomeration. The sintering temperature causes the binder to vitrify and form a dense structure (grinding layer 5 density ≥ 2.2g / cm³).

[0042] The spacer 4 mentioned in step S3 is a detachable rigid block with a thickness equal to the gap of the target annular groove 7. It is made of metal or ceramic and is removed after bonding and curing.

[0043] The spacer 4 (made of metal / ceramic material, with a thickness equal to the gap of the target annular groove 7) serves as a temporary positioning tool to ensure that the gap of the grinding layer 5 is uniform (groove width accuracy ±0.05mm). It is removed after bonding and curing, without affecting the cooling / chip removal function of the annular groove 7.

[0044] The positioning fixture is a concentric positioning and axial pressure fixture, comprising the platform 2, the positioning group, the gravity plate 1, and the telescopic support rod 3; the positioning group is fixedly connected to the platform 2 and is used to support and position the center positioning holes 8 of the bottommost and topmost segment bases; the gravity plate 1 is connected to the telescopic support rod 3 and is used to abut against the center positioning hole 8 of the topmost segment base and apply axial pressure to ensure that the coaxiality of the segment bases does not exceed 0.01mm; the telescopic support rod 3 is used to adjust the distance between the gravity plate 1 and the platform 2 to accommodate different numbers of segment bases.

[0045] Thus, the positioning fixture structure (platform 2, positioning group, gravity plate 1, telescopic support rod 3) and positioning logic (top center positioning hole 8 abuts against gravity plate 1, bottom abuts against platform 2 positioning group) are clearly defined. "Bidirectional axial positioning" ensures the coaxiality of the segmented substrate is ≤0.01mm. This fixture design ensures that the parallelism error between gravity plate 1 and platform 2 is ≤0.005mm, and the axial pressure uniformity is ≥95%, avoiding excessive dynamic balance of the grinding wheel (imbalance >5g·cm) caused by uneven adhesive layer thickness.

[0046] The curing conditions for the adhesive layer in step S4 are: temperature 80℃ to 120℃, time 2 hours to 4 hours, and the thickness uniformity error of the cured adhesive layer does not exceed 0.02mm.

[0047] Therefore, the curing conditions for the adhesive layer are defined (80-120℃, 2-4h) to ensure full cross-linking of the modified epoxy resin. Temperatures that are too low (<80℃) will result in incomplete curing and a tensile strength <20MPa; temperatures that are too high (>120℃) will cause the adhesive layer to crack. The adhesive layer cured under these conditions has a thickness uniformity error ≤0.02mm, a tensile strength ≥30MPa, and a temperature resistance ≥200℃, meeting the thermal stability requirements during high-speed grinding (≥3000r / min).

[0048] The static balance verification in step S5 is completed using a dynamic balancing machine, and the circular runout of the outer surface of the finely ground layer 5 does not exceed 0.01mm.

[0049] Thus, static balancing (dynamic balancing machine) ensures that the unbalance of the grinding wheel is ≤5g·cm, avoiding vibration during high-speed rotation (vibration amplitude <0.005mm), and the roundness error of the workpiece is ≤0.002mm; the fine grinding of the outer cylindrical surface of grinding layer 5 (Ra≤0.8μm) ensures that the circular runout of the grinding surface is ≤0.01mm, solving the problem of the flatness deviation of the outer cylindrical surface (≤0.02mm) after the sintering of the segmented substrate, ensuring that the surface roughness of the workpiece is stable at Ra0.6-0.8μm during grinding, meeting the grinding requirements of precision parts (such as aero-engine blades).

[0050] Example 2: Manufacturing of a 7-groove annular groove grinding wheel (suitable for high-speed grinding) S1 segmented substrate prefabrication: A ceramic binder and diamond abrasive grains were pressed together using a hot-pressing process (temperature 1100℃, pressure 12MPa), and then sintered at high temperature (1200℃) to form a segmented matrix. The grinding layer 5 has a density of 2.4 g / cm³, a porosity of 18%, and a thickness of 8 mm; the matrix layer 6 has a thickness of 35 mm and a flexural strength of 58 MPa. A 45 mm diameter central positioning hole 8 is machined at one end of the matrix layer 6, and an 8 mm diameter intermediate positioning hole is machined at the other end, neither of which penetrates the grinding layer 5.

[0051] S2 mating surface processing: The six mating surfaces of the substrate layer were ground to achieve a flatness of ≤0.01mm and Ra=2.5μm. Subsequently, the surfaces were chemically activated by soaking in a 10% phosphoric acid solution for 5 minutes to enhance the bonding strength of the adhesive layer.

[0052] S3 Positioning Assembly: Position the two segmented substrates by inserting positioning posts through the middle positioning holes; the top center positioning hole 8 abuts against the gravity plate 1, and the bottom abuts against the platform 2 positioning group; insert 0.15mm thick ceramic spacers 4 (thickness equal to the gap of the target annular groove 7) to ensure uniform groove width.

[0053] S4 Axial Pressure Bonding: Gravity plate 1 is connected to platform 2 via telescopic struts 3. After adhesive is applied, gravity plate 1 is released to apply its own weight pressure. The mass of gravity plate 1 is calculated based on the total area of ​​the joint surfaces of the segmented substrates and the required axial pressure (0.8 MPa, based on the design requirement of tensile strength of the adhesive layer ≥ 30 MPa). The calculation formula is: Mass = (Axial pressure × Total area of ​​joint surfaces) / Gravitational acceleration. For example, if the total area of ​​the joint surfaces of the segmented substrates is 100 cm² (i.e., 0.01 m²), then the mass of gravity plate 1 is approximately 80 kg (0.8 × 10⁻⁶ m²). 6 Pa × 0.01m² / 9.8m / s² ≈ 81.6kg (rounded to 80kg). The entire assembly is then transferred to a constant temperature oven (90℃, 2.5h) for curing, forming an adhesive layer (0.05mm thick). Together with the inner gap (0.1mm) of the grinding layer 5, it forms an inclined annular groove 7 with a groove width of 0.15mm and a groove depth of 8mm (equal to the thickness of the grinding layer 5) (the groove wall makes an angle of 20° with the axis).

[0054] S5 Post-processing: Remove partition 4 and gravity plate 1; check the static balance and the unbalance amount is 2.5 g·cm; grind the outer circle of the grinding layer 5 to Ra=0.7μm and the circular runout ≤0.008mm.

[0055] Test data: Compared with traditional vertical groove grinding wheels, the coolant coverage increased from 45% to 92% during high-speed grinding (3500r / min), the grinding temperature decreased from 850℃ to 580℃ (a reduction of 32%), the amount of grinding debris was reduced by 65%, and the grinding wheel life increased from 180 hours to 260 hours (an increase of 44%).

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A segmented adhesive grinding wheel, characterized in that, include: At least two axially segmented substrates are spliced ​​along the axis of the grinding wheel. Each segmented substrate is an integrally formed structure, comprising a grinding layer on the outer side and a substrate layer on the inner side of the grinding layer. The grinding layer is composed of superhard abrasive grains bonded by a ceramic binder, with a density of not less than 2.2 g / cm³ and a porosity of 15% to 25%. The substrate layer is a support structure and is integrally sintered with the grinding layer. An annular groove is formed by the gap between the grinding layers of two adjacent segmented substrates and the thickness of the bonding layer at the mating surface of the substrate layers. The groove shape can be planar, stepped, or inclined, wherein: the groove wall of a planar groove is perpendicular to the grinding wheel axis; the groove wall of a stepped groove has steps perpendicular to the groove wall; the angle between the groove wall and the grinding wheel axis of an inclined groove is 10° to 30°; the groove width is equal to the sum of the gap between the grinding layers of adjacent segmented substrates and the thickness of the bonding layer, and the groove depth is equal to the thickness of the grinding layer. The adhesive layer, located between the mating surfaces of the substrate layers of two adjacent segmented substrates, is made of modified epoxy resin, with a thickness of 0.05mm to 0.2mm, a tensile strength of not less than 30MPa, and a temperature resistance of not less than 200℃. Positioning hole system, including: The central positioning hole is vertically opened at one end of the segmented substrate layer, located at the central axis position, and does not penetrate the substrate layer; The central positioning hole is vertically opened at the other end of the segmented substrate layer, located at a position not on the central axis. The central positioning hole is used to cooperate with the positioning fixture to achieve axial positioning, and the intermediate positioning hole is used to insert a positioning post between two adjacent segmented substrates to achieve rapid central positioning.

2. The segmented bonded grinding wheel according to claim 1, characterized in that, The superhard abrasive grains are cubic boron nitride or diamond, and the material of the substrate layer is the same as the ceramic binder of the grinding layer.

3. The segmented bonded grinding wheel according to claim 1, characterized in that, The outer surface of the grinding layer is continuous and uninterrupted, and it comes into direct contact with the workpiece being ground during grinding.

4. The segmented bonded grinding wheel according to claim 1, characterized in that, The width accuracy of the annular groove is ±0.05mm, and the depth accuracy is ±0.1mm.

5. A method for manufacturing a segmented bonded grinding wheel, used to manufacture the segmented bonded grinding wheel according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1 Segmented Substrate Prefabrication: The ceramic binder and superhard abrasive grains are pressed into shape using a hot pressing process, and then sintered at high temperature to form an integral segmented substrate containing a grinding layer and a substrate layer; a central positioning hole is provided at one end of the substrate layer, and an intermediate positioning hole is provided at the other end; none of the positioning holes penetrate the substrate layer. S2 mating surface processing: The mating surfaces of the segmented substrate layers are finely ground or polished to ensure that the flatness does not exceed 0.02mm and the surface roughness Ra does not exceed 3.2μm. Subsequently, the substrate layer is ultrasonically cleaned and activated to enhance the bonding force. S3 Positioning Assembly: Multiple segmented substrates are quickly centered by inserting positioning pins through the middle positioning holes; the center positioning hole of the top segmented substrate abuts against the gravity plate, and the center positioning hole of the bottom segmented substrate abuts against the platform positioning group. An annular groove is formed between two adjacent segments of substrates, and spacers are used between the annular grooves to control the gap between the grinding layers of adjacent segments of substrates. S4 Axial Pressure Bonding: The gravity plate and platform are distributed in parallel and connected by telescopic struts. Modified epoxy resin is applied to the mating surface of the substrate layer. Then the gravity plate is released, so that the gravity plate applies pressure to the segmented substrate along the axial direction by its own weight. Subsequently, the gravity plate, platform and grinding wheel are transferred to a constant temperature oven for curing to form a strong adhesive layer. The thickness of this adhesive layer and the gap reserved on the inner side of the grinding layer of the adjacent two segmented substrates together form the annular groove on the working surface of the grinding wheel. S5 Post-treatment: After curing, remove the spacers and gravity plates, and perform static balance verification on the grinding wheel to ensure that the imbalance does not exceed 5 g·cm; perform fine grinding on the outer cylindrical surface of the grinding layer to ensure that the surface roughness Ra does not exceed 0.8 μm.

6. The method for manufacturing a segmented bonded grinding wheel according to claim 5, characterized in that, The hot pressing process parameters in step S1 are: temperature 800℃ to 1200℃, pressure 5MPa to 20MPa; the high-temperature sintering temperature is 1000℃ to 1300℃, and the flexural strength of the sintered segmented matrix is ​​not less than 50MPa.

7. The method for manufacturing a segmented bonded grinding wheel according to claim 5, characterized in that, The spacer mentioned in step S3 is a detachable rigid block with a thickness equal to the target annular groove gap. It is made of metal or ceramic and is removed after bonding and curing.

8. The method for manufacturing a segmented bonded grinding wheel according to claim 5, characterized in that, The positioning fixture is a concentric positioning and axial pressure fixture, comprising the platform, positioning assembly, gravity plate, and telescopic support rod. The positioning assembly is fixedly connected to the platform and is used to support and position the center positioning holes of the bottommost and topmost segmented bases. The gravity plate is connected to the telescopic support rod and is used to abut against the center positioning hole of the topmost segmented base and apply axial pressure to ensure that the coaxiality of the segmented bases does not exceed 0.01mm. The telescopic support rod is used to adjust the distance between the gravity plate and the platform to accommodate different numbers of segmented bases.

9. The method for manufacturing a segmented bonded grinding wheel according to claim 5, characterized in that, The curing conditions for the adhesive layer in step S4 are: temperature 80℃ to 120℃, time 2 hours to 4 hours, and the thickness uniformity error of the cured adhesive layer does not exceed 0.02mm.

10. The method for manufacturing a segmented bonded grinding wheel according to claim 5, characterized in that, The static balance verification in step S5 is completed using a dynamic balancing machine, and the circular runout of the outer surface of the finely ground layer does not exceed 0.01mm.

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