Ceramic material slotting metal bond grinding wheel and its preparation method

Abstract

The application discloses a metal binder grinding wheel for slotting ceramic material and a preparation method thereof, and belongs to the technical field of superhard material preparation. In the preparation process of the grinding wheel, the contact part of the steel base body and the abrasive layer is pretreated, which can promote the steel base body surface to form many semispherical pits, increase the contact area of the steel base body and the abrasive layer, and improve the holding force of the steel base body on the abrasive layer, so that the bonding strength between the steel base body and the abrasive layer is improved, and the abrasive layer ring-off phenomenon in the processing process is avoided. The steel base body feeding area is designed as an L-shaped step, so that the contact area of the abrasive layer and the steel base body is increased. The abrasive layer can also tightly clamp the steel base body due to shrinkage. The coaxiality of the abrasive layer and the steel base body is less than or equal to 0.008 mm, and the parallelism of the end surface of the grinding wheel is less than or equal to 0.015 mm.

Description

Technical Field

[0001] This invention belongs to the field of superhard material preparation technology, specifically relating to a metal-bonded grinding wheel for grooving ceramic materials and its preparation method. Background Technology

[0002] Fiber optic ceramic ferrules, also known as ceramic ferrules, are precision-aligned cylinders in fiber optic connector plugs. They are high-precision special ceramic components made from nano-zirconia (ZrO2) material through a series of formulations and processing steps. The precision grooving of these high-precision special ceramic components places comprehensive performance requirements on the grinding wheels, demanding high shape retention, high wear resistance, high sharpness, and high material removal rate. Furthermore, the chipping at the groove opening must be less than 40μm. The processing equipment can automatically detect the chipping size; if it exceeds 40μm, the equipment alarms and stops working. Currently, imported metal-bonded grooving grinding wheels are used for processing.

[0003] These grinding wheels have large diameters and thicknesses (over 200mm in diameter and over 20mm in thickness), and each wheel has a reinforcing flange on one side. They are manufactured using the conventional 1A1 type grinding wheel bonding method with the reinforcing flange, which easily leads to severe wheel runout and flange delamination during use. Compared to the outer diameter of the grinding wheel, the abrasive working layer is relatively narrow (≤10mm). If the bonding strength between the working layer and the steel substrate is low, the abrasive layer is prone to detaching completely during grooving. Currently, these types of grinding wheels are mainly imported, with few reports on them domestically, requiring further research. Summary of the Invention

[0004] To overcome the problems in the prior art, the present invention provides a metal-bonded grinding wheel for grooving ceramic materials (grinding wheel drawing as shown). Figure 1 and Figure 2 As shown, the steel substrate and reinforcing flange are designed as a whole to ensure that the parallelism of the two end faces of the grinding wheel is ≤0.015mm and the runout of the working layer is ≤0.015mm. During the manufacturing process of this grinding wheel, the contact surface between the steel substrate and the abrasive working layer is specially treated, and the grinding wheel is then manufactured on the basis of this treatment. This grinding wheel can be used for grooving of ceramic core workpieces, and can meet the requirement that the chipping of the workpiece groove is <40μm. Moreover, the grinding wheel has sharp grooving and good wear resistance, which meets the customer's quality requirements.

[0005] A metal-bonded grinding wheel for grooving ceramic materials, the grinding wheel comprising a substrate and an abrasive layer disposed on the surface of the substrate; the abrasive layer is made of a main abrasive and a metal binder, the main abrasive being diamond, and the metal binder being composed of the following components by weight percentage: copper powder, tin powder, nickel powder, silver powder, and graphite, with the following weight parts for each raw material: diamond 20-40 parts, copper powder 60-70 parts, tin powder 10-20 parts, nickel powder 5-15 parts, silver powder 5-15 parts, and graphite 2-8 parts; the diamond particle size is 35-91 μm; and all components of the metal binder are in powder form with a particle size greater than or equal to 170 mesh.

[0006] Furthermore, the substrate has a toothless structure, and an L-shaped step is formed on the outer edge of the upper surface of the substrate. The L-shaped step is 5-10 mm wide and 1.0-2.0 mm deep, and is used to accommodate the abrasive layer.

[0007] Furthermore, the total width of the abrasive layer is 5~10mm, the thickness of the effective grinding area is 0.5mm~1.5mm, and the width of the effective grinding area is 2~4mm.

[0008] The preparation method of the metal-bonded grinding wheel for grooving ceramic materials described above is as follows: (1) Matrix machining: rough turning of the matrix, surface grinding of the matrix, and finish turning of the matrix to form an L-shaped step; (2) Mixing: Mix the components of the metal binder, the main abrasive and the wetting agent for 2-5 hours to obtain a mixture; (3) Substrate pretreatment: After cleaning the substrate, laser treatment is performed, followed by cleaning and drying, and then sandblasting. (4) Molding and sintering: The matrix from step (3) and the mixture from step (2) are put into the mold, spread out, scraped flat, and then placed in an atmosphere sintering furnace for sintering and molding. The specific sintering process is as follows: Under hydrogen atmosphere, at a sintering temperature of 800~950℃ and a sintering pressure of 10~15MPa, the heat treatment is carried out for 1~2 hours. After the heat treatment is completed, the temperature is lowered to room temperature and demolded to obtain the grinding wheel blank. (5) Machining: Machining the outer end face and inner hole of the grinding wheel blank in step (4). Using the inner hole as the positioning reference, positioning holes are made on the steel substrate on one side of the abrasive layer to finally obtain the semi-finished grinding wheel. (6) Grinding of the effective grinding area of ​​the abrasive layer: The abrasive layer of the semi-finished grinding wheel in step (5) is ground with resin superhard grinding wheel to make the effective grinding area 0.5mm~1.5mm thick × 2mm~4mm wide. Before processing, the runout of the substrate end face should be ≤0.01mm. After processing, the runout of the abrasive layer end face should be ≤0.015mm to be qualified. (7) Dynamic balancing correction: On a high-precision dynamic balancing machine, the weight is removed by drilling holes. If the dynamic imbalance is ≤0.2g, it is considered a finished product.

[0009] Furthermore, the specific process of step (3) is as follows: S1. Acid wash the matrix in 90-95 wt% nitric acid for 5-10 min, then rinse with distilled water, then alkali wash in 40-50 wt% NaOH aqueous solution for 5-10 min to remove impurities and oil, then rinse with distilled water and dry. S2. Place the dried substrate from step S1 into a laser engraving machine and laser engrave uniform hemispherical pits on the bottom surface of the L-shaped step. The radius of the hemispherical pits is 0.1~0.3mm. S3. Wash the matrix obtained in step S2 with pure water and dry it; S4. In order to increase the surface roughness of the steel substrate and treat the oxide layer after laser blasting, the substrate treated in S3 is placed in a sandblasting machine and the surface of the substrate is treated with 80-150 mesh corundum sand.

[0010] Preferably, the bottom surface of the L-shaped step has 5 to 10 hemispherical pits radially distributed. The sandblasting pressure is 100 to 200 kg / cm². 2 The sandblasting time is 10-30 seconds. The power of the laser engraving machine is 50-100W.

[0011] Furthermore, in step (2), the wetting agent is liquid paraffin. Based on the total weight of the main abrasive and the metal binder, 10-20 mL of liquid paraffin needs to be added per 1 kg. The wetting agent evaporates during the sintering and molding process.

[0012] Furthermore, in step (5), the positioning hole is a countersunk hole with a diameter of 6~7mm, and 4~6 positioning holes are evenly distributed along the inner circumference of the working surface of the substrate abrasive layer.

[0013] Furthermore, in step (5), after the grinding wheel is processed, the coaxiality between the abrasive layer and the substrate is ≤0.008mm; the upper end surface of the working layer of the abrasive layer is at the same height as the substrate, and the parallelism with the bottom surface of the substrate is ≤0.015mm.

[0014] The innovation of this invention lies in: 1) Pretreatment of the contact area between the steel substrate and the abrasive layer during the grinding wheel preparation process can promote the formation of many hemispherical pits on the surface of the steel substrate, increase the contact area between the steel substrate and the abrasive layer, and the abrasive layer fills into the pits, which improves the holding force of the steel substrate on the abrasive layer, thereby improving the bonding strength between the steel substrate and the abrasive layer and avoiding the phenomenon of abrasive layer detachment during the processing.

[0015] 2) The steel substrate feeding area is designed with an L-shaped step, which increases the contact area between the abrasive layer and the steel substrate. The shrinkage of the abrasive layer also firmly clamps the steel substrate.

[0016] 3) The coaxiality between the abrasive layer and the steel substrate of the metal bonded grinding wheel obtained by this method is ≤0.008mm, and the parallelism of the grinding wheel end face is ≤0.015mm; Compared with the prior art, the beneficial effects of the present invention are as follows: 1) The grinding wheel blank produced by this invention has a simple processing technology and is easy to operate; 2) By pre-treating the steel substrate with laser, the bonding strength between the steel substrate and the abrasive layer is improved, thus avoiding the phenomenon of the abrasive layer de-ringing during use; 3) The grinding wheel of this invention can be used for grooving of optical fiber ceramic ferrule materials. Compared with imported grinding wheels, it meets the requirement of workpiece groove edge chipping <40μm, has good wear resistance, high batch stability, and can achieve domestic substitution. Attached Figure Description

[0017] Figure 1 Schematic diagram of a metal-bonded grinding wheel; Figure 2 This is a magnified view of a portion of the working part of the metal-bonded abrasive layer; Figure 3 This is a schematic diagram of the surface state of the steel substrate after laser treatment. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the following embodiments, the particle size of the raw materials used—copper powder, tin powder, nickel powder, silver powder, and graphite—is ≤50μm, and these are commercially available products. The abrasive diamond is a commercially available product.

[0020] Example 1 A metal-bonded grinding wheel for grooving ceramic materials, such as Figure 1 As shown, it includes a steel substrate and an abrasive layer, wherein the abrasive layer includes abrasive and a metal binder, specifically composed of the following raw materials in parts by weight: 65 parts copper powder, 15 parts tin powder, 10 parts nickel powder, 10 parts silver powder, 5 parts graphite, and 30 parts diamond (400 mesh).

[0021] One side of the steel substrate has a trapezoidal structure, which serves as the substrate reinforcement flange. In this invention, the grinding wheel model used is 3A1 D200×T20.2×H24×E0.5×X7, where: D represents the diameter of the grinding wheel, T represents the total thickness of the grinding wheel, H represents the diameter of the inner hole of the grinding wheel, E represents the thickness of the effective grinding area of ​​the abrasive layer, and X represents the total width of the abrasive layer; all units are in mm.

[0022] The preparation method of the above-mentioned metal-bonded grinding wheel specifically includes the following steps: (1) Matrix machining: The matrix is ​​rough-turned, surface-ground, and finish-turned. An L-shaped step is finish-turned on the outer edge of the upper end face of the matrix. The L-shaped step is 7mm wide and 1.5mm deep, for the abrasive layer to be added during forming. Compared with conventional grinding wheel matrix, the steel matrix is ​​toothless. The matrix structure is as follows: Figure 2 As shown.

[0023] (2) Take 65 parts of copper powder, 15 parts of tin powder, 10 parts of nickel powder, 10 parts of silver powder, 5 parts of graphite, and 30 parts of diamond (mesh size of 400 mesh). Based on the total weight of the above raw materials, add 20 mL of liquid paraffin to each 1 kg of raw materials. Add the raw materials and liquid paraffin to the mixing tank and seal it. Put the sealed mixing tank into the three-dimensional mixer and mix for 3 hours to obtain the mixture. (3) Pretreatment of steel substrate S1. Pre-treatment cleaning: The steel substrate was pickled in a 90% nitric acid solution for 10 minutes, rinsed with distilled water, then alkaline washed in a 50% NaOH aqueous solution for 10 minutes to remove impurities and oil stains, rinsed with distilled water again, and dried. S2, laser The dried steel substrate from step S1 is placed in a laser engraving machine (50W). Uniform hemispherical pits with a radius of 0.1mm are laser-engraved on the bottom surface of the L-shaped step. Five to ten hemispherical pits are radially distributed on the bottom surface of the L-shaped step. The effect after laser engraving is as follows: Figure 3 As shown.

[0024] S3, Washing and Drying The steel substrate obtained in step S2 is washed three times with pure water and then dried in a vacuum drying oven at 50°C for 10 minutes.

[0025] S4, Sandblasting treatment of steel substrate The S3-treated steel substrate is placed in a sandblasting machine (sandblasting pressure 150 kg / cm²). 2 In the sandblasting process (20s), 100-mesh corundum sand is used to treat the substrate surface, mainly to increase the surface roughness of the steel substrate and to treat the oxide layer after laser blasting.

[0026] (4) Molding and sintering: The steel substrate from step (3) and the mixture from step (2) are put into the mold, spread out, scraped flat, and then placed in an atmosphere sintering furnace for sintering and molding. The specific sintering process is as follows: Under hydrogen atmosphere, at a sintering temperature of 800℃ and a sintering pressure of 10MPa, the heat treatment is carried out for 4 hours. After the heat treatment is completed, the temperature is lowered to room temperature and demolded to obtain the grinding wheel blank. (5) Machining: The outer end face and inner hole of the grinding wheel blank in step 4) are machined. With the inner hole as the positioning reference, positioning holes (4 to 6 through holes with a diameter of 6.6 mm) are made on the steel substrate on one side of the working layer of the abrasive layer. After the grinding wheel is machined, the coaxiality between the abrasive layer and the substrate is ≤0.008 mm, the upper end face of the working layer of the abrasive layer is at the same height as the substrate, and the parallelism with the bottom surface of the substrate is ≤0.015 mm, thus obtaining the semi-finished grinding wheel. (6) Grinding of the effective grinding zone of the abrasive layer: The abrasive layer is ground with a resin superhard grinding wheel and finished to a thickness of 0.5 mm and a width of 4 mm. Before grinding, the runout of the substrate end face should be ≤0.01 mm. After grinding, the runout of the abrasive layer end face should be ≤0.015 mm to be considered qualified.

[0027] (7) Dynamic balancing correction: On a high-precision dynamic balancing machine, the weight is removed by drilling holes. If the dynamic imbalance is ≤0.2g, it is considered a finished product.

[0028] The ceramic workpieces processed have groove dimensions of 0.5mm width × 0.8mm depth. At a grinding wheel speed of 30m / s, 100 pieces can be processed continuously without any chipping or cracks greater than 40μm at the groove opening. Each grinding wheel can process more than 1000 pieces without dressing, and the groove shape is well maintained, meeting customers' batch processing needs.

[0029] Example 2 The metal-bonded grinding wheel provided in this embodiment, compared with that in Embodiment 1, has the following adjustments to the abrasive layer thickness and ring width: The grinding wheel model used is 3A1 D200×T20.2×H24×E1.5×X10, where D represents the diameter of the grinding wheel, T represents the total thickness of the grinding wheel, H represents the diameter of the inner hole of the grinding wheel, E represents the thickness of the effective grinding area of ​​the abrasive layer, and X represents the total width of the abrasive layer. All units are in mm.

[0030] Compared with the preparation method of the metal-bonded grinding wheel in Example 1, some preparation parameters were adjusted as follows: In step (1), the L-shaped step of the steel base is 10mm wide and 2.5mm deep; Step (4) Molding and sintering: Under a hydrogen atmosphere, at a sintering temperature of 850℃ and a sintering pressure of 15MPa, the material is kept at a heat treatment temperature for 4 hours. After the heat treatment is completed, the material is cooled to room temperature and demolded to obtain a grinding wheel blank. Step (6) Grinding of the effective grinding zone of the abrasive layer: Grind the abrasive layer with a resin superhard grinding wheel to a thickness of 1.5mm and a width of 4mm. Before machining, the runout of the substrate end face should be ≤0.01mm. After machining, the runout of the abrasive layer should be ≤0.015mm to be considered acceptable.

[0031] The ceramic workpieces processed have groove dimensions of 1.5mm width × 1.0mm depth. At a grinding wheel speed of 30m / s, 100 pieces can be processed continuously without any chipping or cracks greater than 40μm at the groove opening. Each grinding wheel can process more than 1000 pieces without dressing, and the groove shape is well maintained, meeting customers' batch processing needs.

[0032] Example 3 The metal-bonded grinding wheel provided in this embodiment, compared with embodiment 1, has the following adjustments to the outer diameter of the grinding wheel, the thickness of the abrasive layer, and the ring width: The grinding wheel model used is 3A1 D250×T20.2×H24×E1.5×X10, where D represents the diameter of the grinding wheel, T represents the total thickness of the grinding wheel, H represents the diameter of the inner hole of the grinding wheel, E represents the thickness of the effective grinding area of ​​the abrasive layer, and X represents the total width of the abrasive layer. All units are in mm.

[0033] Compared with the preparation method of the metal-bonded grinding wheel in Example 1, some preparation parameters were adjusted as follows: In step (1), the L-shaped step of the steel base is 10mm wide and 2.5mm deep; Step (4) Molding and sintering: Under a hydrogen atmosphere, at a sintering temperature of 950℃ and a sintering pressure of 25MPa, the material is kept at a heat treatment temperature for 4 hours. After the heat treatment is completed, the material is cooled to room temperature and demolded to obtain a grinding wheel blank. Step (6) Grinding of the effective grinding zone of the abrasive layer: Grind the abrasive layer with a resin superhard grinding wheel to a thickness of 1.5mm and a width of 8mm. Before machining, the runout of the substrate end face should be ≤0.01mm. After machining, the runout of the abrasive layer should be ≤0.015mm to be considered acceptable.

[0034] The ceramic workpieces processed have groove dimensions of 1.5mm width × 1.5mm depth. At a grinding wheel speed of 30m / s, 100 pieces can be processed continuously without any chipping or cracks larger than 40μm at the groove opening. Each grinding wheel can process more than 1000 pieces without dressing, and the groove shape is well maintained, meeting customers' batch processing needs.

[0035] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0036] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", "center", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

Claims

1. A method for preparing a metal-bonded grinding wheel for grooving ceramic materials, characterized in that, The grinding wheel includes a substrate and an abrasive layer disposed on the surface of the substrate. The abrasive layer is made of a main abrasive and a metal binder. The main abrasive is diamond, and the metal binder is composed of the following components by weight percentage: copper powder, tin powder, nickel powder, silver powder, and graphite. The weight parts of each raw material are as follows: diamond 20-40 parts, copper powder 60-70 parts, tin powder 10-20 parts, nickel powder 5-15 parts, silver powder 5-15 parts, and graphite 2-8 parts. The particle size of the diamond is 35-91 μm. All components of the metal binder are in powder form with a particle size greater than or equal to 170 mesh. The preparation process is as follows: (1) Matrix machining: rough turning of the matrix, surface grinding of the matrix, and finish turning of the matrix to form an L-shaped step; (2) Mixing: Mix the components of the metal binder, the main abrasive and the wetting agent for 2-5 hours to obtain a mixture; (3) Substrate pretreatment: After cleaning the substrate, laser treatment is performed, followed by cleaning and drying, and then sandblasting. (4) Molding and sintering: The matrix from step (3) and the mixture from step (2) are put into the mold, spread out, scraped flat, and then placed in an atmosphere sintering furnace for sintering and molding. The specific sintering process is as follows: Under hydrogen atmosphere, at a sintering temperature of 800~950℃ and a sintering pressure of 10~15MPa, the heat treatment is carried out for 1~2 hours. After the heat treatment is completed, the temperature is lowered to room temperature and demolded to obtain the grinding wheel blank. (5) Machining: Machining the outer end face and inner hole of the grinding wheel blank in step (4). Using the inner hole as the positioning reference, positioning holes are made on the steel substrate on one side of the abrasive layer to finally obtain the semi-finished grinding wheel. (6) Grinding of the effective grinding area of ​​the abrasive layer: The abrasive layer of the semi-finished grinding wheel in step (5) is ground with resin superhard grinding wheel to make the effective grinding area 0.5mm~1.5mm thick × 2mm~4mm wide. Before processing, the runout of the substrate end face should be ≤0.01mm. After processing, the runout of the abrasive layer end face should be ≤0.015mm to be qualified. (7) Dynamic balancing correction: On a high-precision dynamic balancing machine, the weight is removed by drilling holes. If the dynamic imbalance is ≤0.2g, it is considered a finished product. The specific process of step (3) is as follows: S1. The matrix is ​​acid-washed in 90-95 wt% nitric acid for 5-10 min, then rinsed with distilled water, then alkali-washed in 40-50 wt% NaOH aqueous solution for 5-10 min, then rinsed with distilled water and dried. S2. Place the dried substrate from step S1 into a laser engraving machine and laser engrave uniform hemispherical pits on the bottom surface of the L-shaped step. The radius of the hemispherical pits is 0.1~0.3mm. S3. Wash the matrix obtained in step S2 with pure water and dry it; S4. Place the substrate treated in S3 into a sandblasting machine and treat the surface of the substrate with 80-150 mesh corundum sand.

2. The preparation method according to claim 1, characterized in that, The substrate has a toothless structure, and an L-shaped step is formed on the outer edge of the upper surface of the substrate. The step is 5-10 mm wide and 1.0-2.0 mm deep. The L-shaped step is used to accommodate the abrasive layer.

3. The preparation method according to claim 1, characterized in that, The total width of the abrasive layer is 5~10mm, the thickness of the effective grinding area is 0.5mm~1.5mm, and the width of the effective grinding area is 2~4mm.

4. The preparation method according to claim 1, characterized in that, The bottom surface of the L-shaped step has 5 to 10 hemispherical pits radially distributed, with a sandblasting pressure of 100 to 200 kg / cm². 2 Sandblasting time is 10~30 seconds.

5. The preparation method according to claim 1, characterized in that, In step (2), the wetting agent is liquid paraffin. Based on the total weight of the main abrasive and the metal binder, 10-20 mL of liquid paraffin needs to be added per 1 kg.

6. The preparation method according to claim 1, characterized in that, In step (5), the positioning hole is a countersunk hole with a diameter of 6-7 mm, and 4-6 positioning holes are evenly distributed along the inner circumference of the working surface of the substrate abrasive layer.

7. The preparation method according to claim 1, characterized in that, In step (5), after the grinding wheel is processed, the coaxiality between the abrasive layer and the substrate is ≤0.008mm, the upper end face of the working layer of the abrasive layer is at the same height as the substrate, and the parallelism between the upper end face of the abrasive layer and the bottom face of the substrate is ≤0.015mm.

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