Cold isostatic pressing device for silicon nitride ceramic ball production

Abstract

The invention belongs to the technical field of silicon nitride ceramic ball production, and particularly relates to a cold isostatic pressing device for silicon nitride ceramic ball production, which comprises a machine body, a driving device arranged on the machine body, a pressing rod arranged on an output shaft of the driving device, a pressure-bearing cylinder arranged in the machine body, and a pressing plate arranged in the pressure-bearing cylinder and in sealing fit with the inner wall of the pressure-bearing cylinder, the pressure rod is connected with the pressure plate and drives the pressure plate to move in the pressure-bearing cylinder, a lower base is arranged at the lower end of the pressure-bearing cylinder, a valve for controlling fluid to enter the pressure-bearing cylinder is arranged in the lower base, a bearing frame is arranged in the pressure-bearing cylinder, and a plurality of bearing balls coated with silicon nitride are arranged on the bearing frame. The bearing ball filled with silicon nitride powder is placed in the fluid of the pressure-bearing cylinder, the silicon nitride powder is wrapped in the bearing ball, and under the action of the driving device, the pressure plate extrudes the fluid and enables the fluid to extrude the bearing ball from all directions, so that the bearing ball is compacted, and a silicon nitride ceramic ball blank with relatively high density is formed.

Description

Technical Field

[0001] The present application belongs to the technical field of silicon nitride ceramic ball production, and in particular relates to a cold isostatic pressing device for producing silicon nitride ceramic balls. Background Art

[0002] At present, the preparation process of silicon nitride ceramic balls usually requires first forming silicon nitride powder, and then cold isostatic pressing and other operations. Cold isostatic pressing equipment is needed to press silicon nitride powder to make the silicon nitride spheres have higher density and higher strength. In the process of silicon nitride powder forming, there are many schemes such as dry pressing, hot pressing, cold isostatic pressing, sintering, etc. Among them, cold isostatic pressing has the following problems: 1. During the pressing process, silicon nitride is placed on the carrier, and the contact position between silicon nitride and the carrier causes the surface of the blank to be rough; 2. Before cold isostatic pressing, the silicon nitride powder is first made into a sphere using a press and a vibrating machine, and then the surface is coated with a rubber layer or a plastic film, and then placed in a cold isostatic pressing device for pressing. The overall process is relatively cumbersome, and if the coating is not strict, the pressing effect of silicon nitride will also be affected. Summary of the invention

[0003] In order to solve the above problems, the present application provides a cold isostatic pressing device for producing silicon nitride ceramic balls.

[0004] The first purpose of the present application is to provide a cold isostatic pressing device for the production of silicon nitride ceramic balls, in which a load-bearing ball filled with silicon nitride powder is placed in the fluid of a pressure cylinder, and the silicon nitride powder is coated in the load-bearing ball. Under the action of a driving device, a pressure plate squeezes the fluid and causes the fluid to squeeze the load-bearing ball from all directions, thereby compacting the load-bearing ball to form a silicon nitride ceramic ball embryo with a relatively high density.

[0005] In order to achieve the first purpose of this application, the technical solution of this application is: A cold isostatic pressing device for producing silicon nitride ceramic balls comprises a machine body, a driving device is arranged on the machine body, a pressure rod is arranged on the output shaft of the driving device, a pressure cylinder is arranged in the machine body, a pressure plate which is sealed with the inner wall of the pressure cylinder is arranged in the pressure cylinder, the pressure rod is connected with the pressure plate and driven by the pressure rod to move the pressure plate in the pressure cylinder, a lower base is arranged at the lower end of the pressure cylinder, a valve for controlling fluid to enter the pressure cylinder is arranged in the lower base, a bearing frame is arranged inside the pressure cylinder, a plurality of bearing balls coated with silicon nitride are arranged on the bearing frame, a manhole is arranged on the pressure cylinder, a sealing cover is arranged on the manhole, an exhaust pipe is arranged on the pressure cylinder, and the exhaust pipe is arranged above the bearing frame.

[0006] Furthermore, a support platform is provided on the outside of the machine body, and the support platform is connected to the ground by an escalator. A manhole is arranged above the support platform so that a person on the support platform can hang or take out the load-bearing ball in the pressure cylinder through the manhole. The support platform is convenient for the operator to reach the manhole and install and disassemble the load-bearing ball, and it is also convenient for the operator to operate at the control console of the support platform. In addition, after using the support platform in this application, the size of the pressure cylinder can be made larger, so that more silicon nitride ceramic ball embryos can be produced at one time.

[0007] Furthermore, a temperature control rod is provided in the pressure cylinder, and the temperature control rod is provided on the lower base. The temperature of the fluid injected into the pressure cylinder is controlled by the temperature control rod. A connecting channel is provided in the lower base, and a lower connecting pipe is provided on the outer side of the lower base. One interface of the valve is connected to the connecting channel, and the other interface of the valve is connected to the lower connecting pipe. The lower connecting pipe is connected to the fluid storage tank. The present application controls the temperature of the fluid in the pressure cylinder by the temperature control rod, and increases the pressure in the pressure cylinder and increases the degree of squeezing of the fluid on the load-bearing ball by appropriately heating the fluid.

[0008] Furthermore, an upper cover is provided at the upper end of the pressure-bearing cylinder, and a connecting cover is provided at the upper end of the upper cover. The pressure rod is matched with the cavity gap of the upper cover, and the pressure rod contacts the connecting cover so that the pressure rod moves along the track in the connecting cover. This structure enables the pressure rod to operate stably and output stable pressure.

[0009] Furthermore, a plurality of sealing rings arranged at intervals are provided on the outer periphery of the pressure plate, and the sealing rings are in contact with the inner wall of the pressure-bearing cylinder, thereby ensuring the sealing contact between the pressure plate and the inner wall of the pressure-bearing cylinder.

[0010] Furthermore, a hook is hung on the support frame, and symmetrically arranged connecting rings are provided on the support balls. The connecting rings of the support balls close to the hooks are connected to the hooks via connecting rods, and the connecting rings of adjacent support balls are connected via connecting rods, so as to avoid placing silicon nitride directly on the support platform in the prior art. This suspension scheme makes the surface of the blank formed by pressing smooth.

[0011] Furthermore, the load-bearing ball includes a rubber sphere, a connecting ring is connected to the rubber sphere, a multi-petal flexible valve is arranged on the rubber sphere, a flexible interface capable of telescopic deformation is arranged inside the rubber sphere, the flexible interface is located on the inner side of the flexible valve, and the flexible valve is squeezed by the fluid to block the flexible interface.

[0012] Furthermore, the flexible joint is arranged eccentrically relative to the flexible valve, and the load-bearing ball can be directly filled with silicon nitride powder, avoiding the winding coating solution used in the prior art.

[0013] The second object of the present application is to provide a cold isostatic pressing method for producing silicon nitride ceramic balls, by which a silicon nitride ceramic ball embryo with a higher density can be obtained.

[0014] To achieve the second purpose of this application, the technical solution of this application is: A cold isostatic pressing method for producing silicon nitride ceramic balls, using the above-mentioned cold isostatic pressing device for producing silicon nitride ceramic balls, comprises the following steps: S1. Inject silicon nitride powder into a bearing ball, and place the bearing ball into a vibration compaction device for compaction; S2. Open the sealing cover on the manhole, connect the bearing balls to each other, hang the bearing balls on the bearing frame, and close the sealing cover; S3, open the valve and inject the fluid into the pressure cylinder; S4, start the driving device, and the driving device drives the pressure rod and the pressure plate to squeeze the fluid in the pressure cylinder; S5, maintain the set pressure for the set time; S6. Open the valve to discharge the fluid in the pressure cylinder, open the sealing cover, and remove the bearing ball from the bearing frame.

[0015] Further, in step S5, the pressure is set to 180 MPa-220 MPa, and the time is set to 85 seconds-180 seconds.

[0016] Compared with the prior art, the beneficial effects of this application are: In the present application, a bearing ball filled with silicon nitride powder is placed in the fluid of a pressure cylinder. Under the action of a driving device, a pressure plate squeezes the fluid and causes the fluid to squeeze the bearing ball from all directions, thereby compacting the bearing ball to form a silicon nitride ceramic ball embryo with a relatively high density.

[0017] The load-bearing ball of the present application is installed on the load-bearing frame of the pressure cylinder by hanging, and does not require a specific supporting structure, so that the fluid can contact more than 99% of the surface of the load-bearing ball. In addition, the loading port of the load-bearing ball adopts a structure that cooperates with a flexible interface and a flexible valve. The fluid is doubly blocked by the flexible interface and the flexible valve to prevent the fluid from entering the interior of the load-bearing ball.

[0018] The present application controls the temperature of the fluid in the pressure-bearing cylinder by a temperature control rod, and increases the pressure in the pressure-bearing cylinder by appropriately heating the fluid, thereby increasing the degree of squeezing of the fluid on the bearing ball, shortening the squeezing time, and increasing the density of the silicon nitride ceramic ball embryo. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0020] Figure 1 This is a schematic diagram of the overall structure of this application on the front side; Figure 2 The overall structure diagram of this application is on the back; Figure 3 A schematic diagram of the internal structure of the present application in the oblique viewing direction; Figure 4 A schematic diagram of the internal structure of the present application in the front view direction; Figure 5 This is a schematic diagram of the structure of the hook in this application cooperating with multiple load-bearing balls; Figure 6 This is a schematic diagram of the structure of the load-bearing ball of this application.

[0021] In the figure: 1. Machine body, 2. Support platform, 3. Escalator, 4. Control console, 5. Pressure cylinder, 6. Upper cover, 7. Connecting cover, 8. Pressure rod, 9. Lower base, 10. Support seat, 11. Bottom plate, 12. Lower connecting pipe, 13. Manhole, 14. Sealing cover, 15. Alarm indicator light, 16. Pressure plate, 17. Sealing ring, 18. Loading frame, 19. Temperature control rod, 20. Connecting channel, 21. Hook, 22. Loading ball, 23. Connecting ring, 24. Connecting rod, 25. Rubber sphere, 26. Flexible valve, 27. Flexible interface. DETAILED DESCRIPTION

[0022] The present application is further described below in conjunction with the accompanying drawings and embodiments.

[0023] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0024] In the present application, terms such as "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "side", "bottom", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. They are relational words determined only for the convenience of describing the structural relationships of the various parts or elements of the present application, and do not specifically refer to any part or element in the present application and should not be understood as limitations on the present application.

[0025] Embodiment: This embodiment is a cold isostatic pressing device for producing silicon nitride ceramic balls. The cold isostatic pressing device has two functions. One is to use the carrying ball 22 to carry the silicon nitride powder and then press it to form a silicon nitride ceramic ball embryo. The second is to dry the formed silicon nitride ceramic ball embryo and then cold isostatic press it, and then sinter and reprocess it to form a usable silicon nitride ceramic ball. The second function is conventional technology. This embodiment mainly describes the first function of the device, that is, pressing the silicon nitride powder into a silicon nitride ceramic ball embryo. From the structure of the cold isostatic pressing device of this embodiment, the cold isostatic pressing device includes a body 1, and a driving device is installed on the body 1. The output of the driving device A pressure rod 8 is installed on the shaft, and the pressure rod 8 is driven by the driving device to generate pressure. A pressure cylinder 5 is installed in the body 1. The pressure cylinder 5 is a cylindrical pressure vessel. The pressure cylinder 5 has a pressure plate 16 that is sealed with the inner wall of the pressure cylinder 5. The pressure rod 8 is connected to the pressure plate 16 and is driven by the pressure rod 8 to move in the pressure cylinder 5. The lower end of the pressure cylinder 5 has a lower base 9, and the lower end of the body 1 has a support seat 10. The lower base 9 and the support seat 10 are installed on the bottom plate 11. The above structure is the basic structure of the cold isostatic pressing device. As a more specific structure of this embodiment, a bearing frame 18 is installed inside the pressure cylinder 5 of this embodiment. The bearing frame 18 is a plurality of criss-crossed steel pipes or steel bars. A number of bearing balls 22 coated with silicon nitride are hung on the frame 18, a manhole 13 is provided on the pressure-bearing cylinder 5, a sealing cover 14 is installed on the manhole 13, after the sealing cover 14, the exhaust pipe and the valve in the lower base 9 are closed, the pressure-bearing cylinder 5 forms a closed pressure vessel, the pressure-bearing cylinder 5 is provided with an exhaust pipe, and the exhaust pipe is arranged above the bearing frame 18, after the pressure-bearing cylinder 5 is injected with fluid, the gas in the pressure-bearing cylinder 5 is discharged along the exhaust pipe, due to the use of the manhole 13 and the pressure-bearing cylinder 5 of this embodiment can hold more bearing balls 22, this embodiment is equipped with a supporting platform 2 on the outside of the body 1, the four legs of the supporting platform 2 are in contact with the ground, in addition, the supporting platform 2 is connected to the ground through an escalator 3, The operator can reach the top surface of the support platform 2 through the escalator 3. The manhole 13 is arranged above the support platform 2 so that a person on the support platform 2 can hang or remove the load-bearing ball 22 in the pressure cylinder 5 through the manhole 13. The control console 4 is installed on the top surface of the support platform 2. In this embodiment, the installation of the support platform 2 facilitates the operator to reach the manhole 13 and install and remove the load-bearing ball 22, and also facilitates the operator to operate on the control console 4 of the support platform 2. In addition, due to the use of the support platform 2, the size of the pressure cylinder 5 in this embodiment can be made larger, especially the height size of the pressure cylinder 5, so that more silicon nitride ceramic ball embryos can be produced at one time.

[0026] A temperature control rod 19 is installed in the pressure cylinder 5, and the temperature control rod 19 is fixed on the lower base 9. The temperature of the temperature control rod 19 is adjusted by the control console 4. The temperature control rod 19 controls the temperature of the fluid injected into the pressure cylinder 5. The lower base 9 has a valve for controlling the fluid to enter the pressure cylinder 5. The lower base 9 has a connecting channel 20. The outer side of the lower base 9 has a lower connecting pipe 12. One interface of the valve is connected to the connecting channel 20, and the other interface of the valve is connected to the lower connecting pipe 12. The lower connecting pipe 12 is connected to the fluid storage tank. In addition, a pump is installed on the lower connecting pipe 12, and the fluid in the fluid storage tank is transferred to the pressure cylinder 5 by the pump. In this embodiment, the temperature of the fluid in the pressure cylinder 5 is controlled by the temperature control rod 19, and the pressure in the pressure cylinder 5 is increased by appropriately heating the fluid and increasing the degree of squeezing of the fluid on the load-bearing ball 22.

[0027] The upper end of the pressure-bearing cylinder 5 of this embodiment is an upper cover 6, and a connecting cover 7 is installed on the upper end of the upper cover 6. The pressure rod 8 is matched with the cavity gap of the upper cover 6. The pressure rod 8 contacts the connecting cover 7 so that the pressure rod 8 moves along the trajectory in the connecting cover 7. This structure makes the pressure rod 8 run stably and output stable pressure. Specifically, as an implementation scheme, this embodiment can consider the power structure of a conventional press, the connecting cover 7 is a copper structure or the inner wall of the connecting cover 7 is a copper structure, the surface of the pressure rod 8 is an external thread structure, and the inner wall of the connecting cover 7 is an internal thread structure. Structure, the pressure rod 8 is screwed on the connecting cover 7, and the driving device adopts a direct-drive servo motor, which drives the pressure rod 8 to rotate and then realizes the movement of the pressure plate 16, which makes the pressure provided by the pressure rod 8 larger and more stable. Alternatively, this embodiment adopts conventional technology and adopts hydraulic power as the power to drive the pressure rod 8 to move. To ensure the sealing of the pressure plate 16, this embodiment installs a plurality of sealing rings 17 arranged at intervals on the outer periphery of the pressure plate 16. The sealing ring 17 contacts the inner wall of the pressure tube 5, thereby ensuring the sealing contact between the pressure plate 16 and the inner wall of the pressure tube 5.

[0028] In this embodiment, a hook 21 is hung on the carrier frame 18, and a symmetrically arranged connecting ring 23 is provided on the bearing ball 22. The connecting ring 23 of the bearing ball 22 close to the hook 21 is connected to the hook 21 through a connecting rod 24, and the connecting rings 23 of adjacent bearing balls 22 are connected through the connecting rod 24, so as to avoid the silicon nitride being directly placed on the bearing platform in the prior art. This hanging scheme makes the surface of the blank formed by pressing smooth. From the material of the bearing ball 22, the present embodiment adopts rubber material. From the specific structure of the bearing ball 22, the bearing ball 22 is similar to a balloon. Specifically, The load-bearing ball 22 includes a rubber sphere 25, a connecting ring 23 is connected to the rubber sphere 25, a multi-petal flexible valve 26 is provided on the rubber sphere 25, a flexible interface 27 capable of expansion and contraction is provided inside the rubber sphere 25, the flexible interface 27 is located on the inner side of the flexible valve 26, and the flexible valve 26 is sealed after being squeezed by the fluid. Specifically, the flexible joint is eccentrically arranged relative to the flexible valve 26, so that the flexible valve 26 can completely block the flexible interface 27. This load-bearing ball 22 can be directly filled with silicon nitride powder, avoiding the use of a winding coating solution in the prior art.

[0029] In addition, an alarm indicator light 15 is installed on the machine body 1, and the alarm indicator light 15 lights up when a malfunction or other problem occurs in the cold isostatic pressing device.

[0030] Based on the above-mentioned cold isostatic pressing device for producing silicon nitride ceramic balls, this embodiment discloses a cold isostatic pressing method for producing silicon nitride ceramic balls, and a silicon nitride ceramic ball blank with a higher density is obtained by using this method.

[0031] A cold isostatic pressing method for producing silicon nitride ceramic balls comprises the following steps: S1, injecting silicon nitride powder into the bearing ball 22, and placing the bearing ball 22 into a vibration compaction device for compaction; The vibration compaction device of this embodiment is a common device, which does not belong to the structure of this embodiment, and is a necessary equipment for forming silicon nitride ceramic spherical embryos; S2, open the sealing cover 14 on the manhole 13, connect the bearing balls 22 to each other, hang the bearing balls 22 on the bearing frame 18, and close the sealing cover 14; S3, open the valve and inject the fluid into the pressure-bearing cylinder 5; S4, start the driving device, and the driving device drives the pressure rod 8 and the pressure plate 16 to squeeze the fluid in the pressure tube 5; S5, maintain the set pressure for the set time; S6. Open the valve to discharge the fluid in the pressure-bearing cylinder 5, open the sealing cover 14, and remove the bearing ball 22 from the bearing frame 18.

[0032] In step S5, the pressure is set to 180 MPa-220 MPa, and the time is set to 85 seconds-180 seconds.

[0033] After step S6 , the flexible interface 27 of the support ball 22 is opened, and the formed silicon nitride ceramic ball blank is taken out from the support ball 22 .

[0034] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0035] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. A cold isostatic pressing device for producing silicon nitride ceramic balls, characterized in that: The machine body (1) comprises a driving device, a pressure rod (8) is arranged on the output shaft of the driving device, a pressure cylinder (5) is arranged in the machine body (1), a pressure plate (16) which is in sealing cooperation with the inner wall of the pressure cylinder (5) is arranged in the pressure cylinder (5), the pressure rod (8) is connected to the pressure plate (16), and the pressure rod (8) drives the pressure plate (16) to move in the pressure cylinder (5); A lower base (9) is provided at the lower end of the pressure-bearing cylinder (5), and a valve for controlling fluid to enter the pressure-bearing cylinder (5) is provided in the lower base (9); A bearing frame (18) is arranged inside the pressure-bearing cylinder (5), a plurality of bearing balls (22) coated with silicon nitride are arranged on the bearing frame (18), a manhole (13) is arranged on the pressure-bearing cylinder (5), and a sealing cover (14) is arranged on the manhole (13); The pressure-bearing cylinder (5) is provided with an exhaust pipe, which is arranged above the bearing frame (18).

2. A cold isostatic pressing device for producing silicon nitride ceramic balls as claimed in claim 1, characterized in that: A support platform (2) is arranged outside the machine body (1), the support platform (2) is connected to the ground via an escalator (3), and a manhole (13) is arranged above the support platform (2) so that a person on the support platform (2) can hang or take out the bearing ball (22) in the pressure cylinder (5) through the manhole (13).

3. A cold isostatic pressing device for producing silicon nitride ceramic balls as claimed in claim 1, characterized in that: A temperature control rod (19) is arranged in the pressure-bearing cylinder (5), and the temperature control rod (19) is arranged on the lower base (9). The temperature control rod (19) controls the temperature of the fluid injected into the pressure-bearing cylinder (5); The lower base (9) has a connecting channel (20) inside, and a lower connecting pipe (12) is provided outside the lower base (9). A pump is provided on the lower connecting pipe (12). One interface of the valve is connected to the connecting channel (20), and the other interface of the valve is connected to the lower connecting pipe (12). The lower connecting pipe (12) is connected to a fluid storage tank.

4. A cold isostatic pressing device for producing silicon nitride ceramic balls as claimed in claim 1, characterized in that: An upper cover (6) is provided at the upper end of the pressure-bearing cylinder (5), and a connecting cover (7) is provided at the upper end of the upper cover (6). The pressure rod (8) is fitted with a cavity gap of the upper cover (6), and the pressure rod (8) is in contact with the connecting cover (7) so that the pressure rod (8) moves along a trajectory inside the connecting cover (7).

5. The cold isostatic pressing device for producing silicon nitride ceramic balls according to claim 1, characterized in that: The outer periphery of the pressure plate (16) is provided with a plurality of sealing rings (17) arranged at intervals, and the sealing rings (17) are in contact with the inner wall of the pressure-bearing cylinder (5).

6. The cold isostatic pressing device for producing silicon nitride ceramic balls according to claim 1, characterized in that: The support frame (18) is provided with a hook (21), and the support balls (22) are provided with symmetrically arranged connecting rings (23); the connecting ring (23) of the support balls (22) close to the hook (21) is connected to the hook (21) via a connecting rod (24), and the connecting rings (23) of adjacent support balls (22) are connected via a connecting rod (24).

7. A cold isostatic pressing device for producing silicon nitride ceramic balls as claimed in claim 6, characterized in that: The load-bearing ball (22) comprises a rubber sphere (25), a connecting ring (23) being connected to the rubber sphere (25), a multi-petal flexible valve (26) being arranged on the rubber sphere (25), a flexible interface (27) capable of stretching and deforming being arranged inside the rubber sphere (25), the flexible interface (27) being located inside the flexible valve (26), and the flexible valve (26) being squeezed by a fluid to block the flexible interface (27).

8. A cold isostatic pressing device for producing silicon nitride ceramic balls as claimed in claim 7, characterized in that: The flexible joint is arranged eccentrically relative to the flexible valve (26).

9. A cold isostatic pressing method for producing silicon nitride ceramic balls, characterized in that: A cold isostatic pressing device for producing silicon nitride ceramic balls according to any one of claims 1 to 8 is used, comprising the following steps: S1, injecting silicon nitride powder into a bearing ball (22), and placing the bearing ball (22) into a vibration compaction device for vibration compaction; S2, opening the sealing cover (14) on the manhole (13), connecting the bearing balls (22) to each other, hanging the bearing balls (22) on the bearing frame (18), and closing the sealing cover (14); S3, open the valve and inject the fluid into the pressure-bearing cylinder (5); S4, starting the driving device, which drives the pressure rod (8) and the pressure plate (16) to squeeze the fluid in the pressure-bearing cylinder (5); S5, maintain the set pressure for the set time; S6. Open the valve to discharge the fluid in the pressure-bearing cylinder (5), open the sealing cover (14), and remove the bearing ball (22) from the bearing frame (18).

10. A cold isostatic pressing method for producing silicon nitride ceramic balls as claimed in claim 9, characterized in that: In step S5, the pressure is set to 180 MPa-220 MPa, and the time is set to 85 seconds-180 seconds.

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