An isostatic pressing die for zirconia structural ceramics

Abstract

The utility model discloses a kind of isostatic pressing forming mould for zirconia structure ceramic, it is related to solid ceramic isostatic pressing forming mould technical field, including upper die assembly and lower die assembly, upper die assembly includes upper die cover, the bottom end outer edge of upper die cover is fixedly connected with annular pressing plate, multiple screw rods are arranged in annular array on pressing plate, in the utility model, after upper die assembly and lower die assembly are buckled, by tightening screw rod, make pressing plate downwards and press tightly annular outer sealing ring one and outer sealing ring two, realize the sealing of mould body opening, can realize good sealing effect under high pressure environment, effectively prevent liquid medium leakage, guarantee the stability and security of isostatic pressing forming process, improve the forming quality of zirconia structure ceramic, by polytetrafluoroethylene film layer and through-hole cooperation, greatly reduce the friction between zirconia ceramic body and mould inner wall, reduce the damage of body in demoulding process, improve the qualified rate of product.

Description

Technical Field

[0001] This utility model relates to the field of solid ceramic isostatic pressing molding die technology, and in particular to an isostatic pressing molding die for zirconia structural ceramics. Background Technology

[0002] Zirconia structural ceramics possess excellent properties such as high strength, high toughness, high temperature resistance, and corrosion resistance, and are widely used in aerospace, machinery manufacturing, and electronic information fields. Isostatic pressing is one of the commonly used methods for preparing zirconia structural ceramics. This method involves placing the blank in an elastic mold and compacting it under the uniform pressure of a high-pressure liquid medium, so that the blank is subjected to the same pressure in all directions.

[0003] For example, Chinese patent CN216682659U discloses a mold for forming solid zirconia ceramic structural parts, including an upper mold cover and a lower mold body. The upper mold cover is sleeved on the outer periphery of the lower mold body. The interior of the lower mold body is a blank forming cavity. The top of the forming cavity of the lower mold body is a sealing port. The upper part of the inner cavity of the upper mold cover is provided with a sealing plug that cooperates with the sealing port of the lower mold body. The lower part of the outer wall of the lower mold body is provided with several sealing protrusions. The lower part of the inner wall of the upper mold cover is provided with a sealing groove corresponding to the sealing protrusions. The outer periphery of the upper mold cover and the lower mold body is provided with a sealing layer.

[0004] Currently, the sealing performance of existing isostatic pressing molds for zirconia structural ceramics is poor, and liquid media leakage is prone to occur under high pressure. When pressurized, liquid media (such as water and oil) seep into the mold, resulting in excessively high local density of the blank or the appearance of water stains and oil stains. After sintering, defects are formed, which not only affects the molding effect but also poses safety hazards. To address the above problems, an isostatic pressing mold for zirconia structural ceramics is proposed. Utility Model Content

[0005] The purpose of this invention is to solve the problems existing in the prior art, and to propose an isostatic pressing mold for zirconia structural ceramics.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an isostatic pressing mold for zirconia structural ceramics, comprising an upper mold assembly and a lower mold assembly. The upper mold assembly includes an upper mold cover, with an annular pressure plate fixedly connected to the outer edge of the bottom end of the upper mold cover. Multiple screws are arranged in an annular array on the pressure plate. The lower mold assembly includes a base plate, a lower mold ring, and a fixing ring. The lower mold ring and the fixing ring are concentrically fixed to the top of the base plate. An annular groove is provided between the lower mold ring and the fixing ring. The bottom end of the upper mold cover is inserted into the annular groove. An outer sealing ring one is fixed to the bottom of the pressure plate, and an outer sealing ring two is fixed to the top of the fixing ring. Multiple fixing plates are fixedly connected in an annular array to the outer edge of the fixing ring. The bottom end of the screw is threadedly connected to the inner side of the fixing plate. A cavity is provided inside the lower mold ring, and two through holes are symmetrically opened through the outer side of the lower mold ring. A polytetrafluoroethylene film layer is provided on the inner wall of the cavity, and a protruding rod is slidably connected to the inner side of the through hole.

[0007] Preferably, the through hole adopts a stepped hole design, with the end of the through hole near the cavity being a small diameter hole and the end away from the cavity being a large diameter hole. The diameter of the large diameter hole is larger than the diameter of the protrusion, and the diameter of the small diameter hole is matched with the diameter of the protrusion.

[0008] Preferably, an inner sealing ring 1 is fixed to the top wall of the upper mold cover, and an inner sealing ring 2 is fixedly connected to the top of the lower mold ring.

[0009] Preferably, the top of the base plate is fixedly connected to a ring array of multiple bases, and the bottom of the pressure plate is fixedly connected to a ring array of multiple inserts, with the bottom end of the inserts plugging into the top of the bases.

[0010] Preferably, the number of bases and fixing plates are equal, and the outer side of the base is fixedly connected to the outer side of the fixing plate.

[0011] Preferably, one end of the protrusion extends to the outside of the through hole.

[0012] Compared with the prior art, the advantages and positive effects of this utility model are as follows:

[0013] 1. In this utility model, after the upper mold assembly and the lower mold assembly are engaged, the inner sealing ring one and the inner sealing ring two are tightly fitted together, and at the same time, the outer sealing ring one and the outer sealing ring two are fitted together. Multiple screws are moved downward and threadedly connected to the fixing plate, thereby making the outer sealing ring one and the outer sealing ring two tightly fitted. By setting a pressure plate, outer sealing ring one and outer sealing ring two at the opening of the mold body, and tightening the screws, the pressure plate presses the annular outer sealing ring one and the outer sealing ring two downward, thereby achieving a seal at the opening of the mold body. It can achieve a good sealing effect under high pressure, effectively prevent liquid medium leakage, ensure the stability and safety of the isostatic pressing process, and improve the molding quality of zirconia structural ceramics.

[0014] 2. In this invention, the polytetrafluoroethylene (PTFE) film layer has an extremely low surface friction coefficient, which reduces the friction between the zirconia ceramic blank and the inner wall of the mold. Simultaneously, by providing through holes and protrusions on the outer side of the lower mold ring, during demolding, after the upper mold assembly is moved downwards, the protrusions are pulled outwards. Compressed air is introduced into the through holes, allowing it to enter the cavity and form an air film between the blank and the inner wall of the mold, further reducing friction and facilitating blank demolding. The interplay between the PTFE film layer on the inner wall and the through holes on the outer wall significantly reduces the friction between the zirconia ceramic blank and the inner wall of the mold, making the demolding process smoother, reducing damage to the blank during demolding, and improving the product qualification rate. Attached Figure Description

[0015] Figure 1 This is a three-dimensional structural schematic diagram of an isostatic pressing mold for zirconia structural ceramics proposed in this utility model;

[0016] Figure 2 This is a schematic diagram of the lower mold assembly of an isostatic pressing mold for zirconia structural ceramics proposed in this utility model;

[0017] Figure 3 This is a front sectional view of an isostatic pressing mold for zirconia structural ceramics proposed in this utility model.

[0018] Figure 4 This utility model proposes an isostatic pressing mold for zirconia structural ceramics. Figure 3 A magnified view of the details at point A in the middle.

[0019] Legend: 1. Upper mold assembly; 2. Lower mold assembly; 11. Upper mold cover; 12. Pressure plate; 13. Screw; 14. Insert block; 15. Inner sealing ring one; 16. Outer sealing ring one; 20. Cavity; 21. Base plate; 22. Base; 23. Lower mold ring; 24. Fixing ring; 25. Annular groove; 26. Fixing plate; 27. Through hole; 28. Protruding rod; 29. ​​Outer sealing ring two; 210. Polytetrafluoroethylene film layer; 211. Inner sealing ring two. Detailed Implementation

[0020] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0022] Example 1: As Figures 1-4 As shown, this utility model provides an isostatic pressing mold for zirconia structural ceramics, including an upper mold assembly 1 and a lower mold assembly 2. The upper mold assembly 1 includes an upper mold cover 11, and an annular pressure plate 12 is fixedly connected to the outer edge of the bottom end of the upper mold cover 11. Multiple screws 13 are arranged in annular array on the pressure plate 12. The lower mold assembly 2 includes a base plate 21, a lower mold ring 23, and a fixing ring 24. The lower mold ring 23 and the fixing ring 24 are concentrically fixed to the top of the base plate 21. An annular groove 25 is provided between the lower mold ring 23 and the fixing ring 24. The bottom end of the upper mold cover 11 is inserted into the annular groove 25. An outer sealing ring 16 is fixed to the bottom of the pressure plate 12, and an outer sealing ring 29 is fixed to the top of the fixing ring 24. Multiple fixing plates 26 are fixedly connected to the outer edge of ring 24 in an annular array. The bottom end of screw 13 is threadedly connected to the inner side of fixing plate 26. A cavity 20 is provided inside the lower mold ring 23. A polytetrafluoroethylene film layer 210 is provided on the inner wall of the cavity 20. An inner sealing ring 15 is fixed to the top wall of upper mold cover 11. An inner sealing ring 211 is fixedly connected to the top of lower mold ring 23. Multiple bases 22 are fixedly connected to the top of base plate 21 in an annular array. Multiple inserts 14 are fixedly connected to the bottom of pressure plate 12 in an annular array. The bottom end of insert 14 is inserted into the top of base 22. The number of bases 22 and fixing plates 26 are equal, and the outer side of base 22 is fixedly connected to the outer side of fixing plate 26.

[0023] The specific settings and functions of this embodiment are described below: The isostatic pressing mold is mainly composed of an upper mold assembly 1 and a lower mold assembly 2. When using this mold to form zirconia structural ceramics, the powder raw material is first placed into the cavity 20, and then the upper mold assembly 1 is placed directly above the lower mold assembly 2. The upper mold assembly 1 is aligned with the base 22 using multiple inserts 14 at the bottom of the upper mold assembly 1. The upper mold assembly 1 is then slowly moved downward until the upper mold assembly 1 and the lower mold assembly 2 are fastened together. At this time, the bottom end of the upper mold cover 11 is inserted into the annular groove 25, and the multiple inserts 14 are inserted into the base 22. The upper mold assembly 1 and the lower mold assembly 2 are fixed by the insertion method, which improves the stability of the mold during forming.

[0024] At this time, the outer sealing ring 16 at the bottom of the pressure plate 12 (the pressure plate 12 is annular) and the outer sealing ring 29 at the top of the fixing ring 24 are fitted together. Multiple screws 13 are moved downward and threadedly connected to the fixing plate 26, so that the outer sealing ring 16 and the outer sealing ring 29 are tightly fitted. By setting the pressure plate 12, the outer sealing ring 16 and the outer sealing ring 29 at the opening of the mold body, and by adding the inner sealing ring 15 to the top wall of the upper mold cover 11 and the inner sealing ring 211 to the top of the lower mold ring 23, when the upper mold assembly 1 and the lower mold assembly 2 are fastened together, the inner sealing ring 15 and the inner sealing ring 211 are tightly fitted. By tightening the screws 13, the pressure plate 12 presses down the annular outer sealing ring 16 and the outer sealing ring 29, thereby achieving a seal at the opening of the mold body. It can achieve a good sealing effect under high pressure, effectively prevent liquid medium leakage, ensure the stability and safety of the isostatic pressing process, and improve the molding quality of zirconia structural ceramics.

[0025] By adding a polytetrafluoroethylene (PTFE) film layer 210 to the inner wall of the cavity 20 in the lower mold ring 23, the PTFE film layer 210 is formed of PTFE film, which has an extremely low surface friction coefficient, thus reducing the friction between the zirconia ceramic preform and the inner wall of the mold.

[0026] Example 2: Figure 2 and Figure 4 As shown, two through holes 27 are symmetrically opened on the outer side of the lower mold ring 23. A protruding rod 28 is slidably connected to the inner side of the through hole 27. The through hole 27 adopts a stepped hole design. The end of the through hole 27 near the cavity 20 is a small diameter hole, and the end away from the cavity 20 is a large diameter hole. The diameter of the large diameter hole is larger than the diameter of the protruding rod 28, and the diameter of the small diameter hole is matched with the diameter of the protruding rod 28. One end of the protruding rod 28 extends to the outside of the through hole 27.

[0027] The overall effect of this embodiment is that by providing a through hole 27 and a protruding rod 28 on the outer side of the lower mold ring 23, the through hole 27 penetrates the wall of the lower mold ring 23, and one end of the through hole 27 communicates with the cavity 20. During demolding, after the upper mold assembly 1 is moved downward, the protruding rod 28 is pulled outward (when molding is required, the protruding rod 28 is pushed back to its original position). At this time, a gap appears between the through hole 27 and the protruding rod 28. By introducing compressed air into the through hole 27, the compressed air enters the cavity 20, forming an air film between the blank and the inner wall of the mold, further reducing friction and facilitating the demolding of the blank. Through the cooperation of the polytetrafluoroethylene film layer 210 on the inner wall and the through hole 27 on the outer wall, the friction between the zirconia ceramic blank and the inner wall of the mold is greatly reduced, making the demolding process smoother, reducing damage to the blank during the demolding process, and improving the product qualification rate.

[0028] The usage and working principle of this device are as follows: Powder raw materials are placed into cavity 20, and upper mold assembly 1 and lower mold assembly 2 are fastened together. At this time, the bottom end of upper mold cover 11 is inserted into annular groove 25, and multiple inserts 14 are inserted into base 22. At this time, outer sealing ring 16 and outer sealing ring 29 are attached together. Multiple screws 13 are moved downward and threadedly connected to fixing plate 26, so that outer sealing ring 16 and outer sealing ring 29 are tightly attached. When upper mold assembly 1 and lower mold assembly 2 are fastened together, inner sealing ring 15 and inner sealing ring 211 are tightly attached. By tightening screws 13, pressure plate 12 is pressed down to press outer sealing ring 16 and outer sealing ring 29, thereby achieving sealing at the opening of mold body. It can achieve good sealing effect under high pressure.

[0029] By adding a polytetrafluoroethylene (PTFE) film layer 210 to the inner wall of the cavity 20 within the lower mold ring 23, the PTFE film layer 210 is formed of PTFE film. PTFE film has an extremely low surface friction coefficient, which can reduce the friction between the zirconia ceramic blank and the inner wall of the mold. At the same time, by setting a through hole 27 and a protrusion 28 on the outer side of the lower mold ring 23, during demolding, after the upper mold assembly 1 is moved downward, the protrusion 28 is pulled outward. Compressed air is introduced into the through hole 27, allowing the compressed air to enter the cavity 20 and forming an air film between the blank and the inner wall of the mold, further reducing the friction. The PTFE film layer 210 on the inner wall and the through hole 27 on the outer wall work together to greatly reduce the friction between the zirconia ceramic blank and the inner wall of the mold, making the demolding process smoother.

[0030] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the present utility model.

Claims

1. An isostatic pressing mold for a zirconia structural ceramic, characterized by: The assembly includes an upper mold assembly (1) and a lower mold assembly (2). The upper mold assembly (1) includes an upper mold cover (11), and an annular pressure plate (12) is fixedly connected to the outer edge of the bottom end of the upper mold cover (11). Multiple screws (13) are arranged in annular array on the pressure plate (12). The lower mold assembly (2) includes a base plate (21), a lower mold ring (23), and a fixing ring (24). The lower mold ring (23) and the fixing ring (24) are concentrically fixed to the top of the base plate (21). An annular groove is provided between the lower mold ring (23) and the fixing ring (24). 25), the bottom end of the upper mold cover (11) is inserted into the annular groove (25), the bottom of the pressure plate (12) is fixed with an outer sealing ring one (16), the top of the fixing ring (24) is fixed with an outer sealing ring two (29), the outer edge of the fixing ring (24) is fixedly connected with multiple fixing plates (26) in an annular array, the bottom end of the screw (13) is threaded to the inner side of the fixing plate (26), the lower mold ring (23) is provided with a cavity (20), and the inner wall of the cavity (20) is provided with a polytetrafluoroethylene film layer (210).

2. The isostatic pressing mold for zirconia structural ceramics according to claim 1, characterized by: Two through holes (27) are symmetrically opened on the outer side of the lower mold ring (23). A protruding rod (28) is slidably connected to the inner side of the through hole (27). The through hole (27) adopts a stepped hole design. The end of the through hole (27) near the cavity (20) is a small diameter hole, and the end away from the cavity (20) is a large diameter hole. The diameter of the large diameter hole is larger than the diameter of the protruding rod (28), and the diameter of the small diameter hole is matched with the diameter of the protruding rod (28).

3. The isostatic pressing mold for zirconia structural ceramics according to claim 1, characterized by: The top wall of the upper mold cover (11) is fixed with an inner sealing ring one (15), and the top of the lower mold ring (23) is fixedly connected with an inner sealing ring two (211).

4. The isostatic pressing mold for zirconia structural ceramics according to claim 1, characterized in that: The top of the base plate (21) is fixedly connected to a ring array of multiple bases (22), and the bottom of the pressure plate (12) is fixedly connected to a ring array of multiple inserts (14). The bottom end of the insert (14) is inserted into the top of the base (22).

5. The isostatic pressing mold for zirconia structural ceramics according to claim 4, characterized by: The number of bases (22) and fixing plates (26) are equal, and the outer side of the base (22) is fixedly connected to the outer side of the fixing plate (26).

6. The isostatic pressing mold for zirconia structural ceramics according to claim 1, characterized by: One end of the protruding rod (28) extends to the outside of the through hole (27).

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