An isostatic pressing method and die for ceramic roller bars

Abstract

The application discloses an isostatic pressing forming method and a die for a ceramic roller, and relates to the technical field of ceramic roller processing and manufacturing. The isostatic pressing forming method comprises the following steps: sleeving an elastic forming pipe outside a rigid inner supporting pipe, wherein the rigid inner supporting pipe is provided with a through hole; placing the rigid inner supporting pipe in a rigid outer supporting pipe, so that a forming cavity is formed between the elastic forming pipe and the rigid outer supporting pipe; filling ceramic powder into the forming cavity and sealing the ceramic powder, so that a first component combination is obtained; sleeving the first component combination into a flexible sealing pipe and sealing the first component combination, so that a second component combination is obtained; performing isostatic pressing treatment on the second component combination, wherein an isostatic pressing medium performs radial pressing on the ceramic powder from inside to outside through the elastic forming pipe, so that a ceramic roller blank pipe is obtained; and discharging the ceramic roller blank pipe subjected to the isostatic pressing treatment and performing sintering, so that the ceramic roller is obtained. The isostatic pressing forming method can directly perform isostatic pressing forming on dry ceramic powder to obtain the ceramic roller blank pipe.

Description

Technical Field

[0001] This invention relates to the field of ceramic roller processing and manufacturing technology, and in particular to an isostatic pressing method and mold for ceramic rollers. Background Technology

[0002] Currently, the production of ceramic rollers mainly employs vacuum extrusion molding. This molding method involves vacuum extruding pre-prepared ceramic clay, and by kneading the clay and removing air from it, the density and overall strength of the billet can be improved. Before the clay enters the vacuum extruder, the raw material needs to undergo multiple kneading and aging processes to eliminate air and gaps in the billet and ensure uniform distribution of powder particles, moisture, and additives. Only after multiple kneading processes can it be fed into the vacuum extruder. Vacuum extrusion molding has problems such as numerous processes, long production cycles, and complex operation. In addition, vacuum extrusion molding has high requirements for the production environment; factors such as temperature and humidity can affect it. At the same time, vacuum extrusion molding has high requirements for the billet, requiring precise control of powder particle size, solvent, plasticizer, and binder dosages, as well as the uniformity of the clay. Furthermore, the heat generation of the vacuum extruder must be strictly controlled; otherwise, it can lead to a decrease in the roundness and straightness of the billet tube, or even cracking. Moreover, the extruder nozzle structure is complex and requires high processing precision.

[0003] Compared to vacuum extrusion molding, isostatic pressing using dry powder offers advantages such as simpler process, easier operation, and shorter cycle time. The preform produced by isostatic pressing exhibits high density, low dimensional shrinkage, high mechanical strength, and stable product performance.

[0004] Currently, there are some research reports on the isostatic pressing process for ceramic rollers. For example, Chinese patent document CN101298171A discloses an isostatic pressing method for ceramic tubes. However, due to the use of flexible inner and outer molds and the lack of rigid support, this method is only suitable for bidirectional pressure to improve the density of pre-formed vacuum extruded billets. Chinese patent document CN104118047B discloses an isostatic pressing process for ceramic roller billets. This process mainly improves the strength, density, roundness, and straightness of vacuum extruded billets through isostatic pressing. Although this process uses a rigid outer mold, because the inner mold is flexible, it is only suitable for isostatic pressing densification of pre-formed vacuum extruded billets and cannot be directly used for isostatic pressing of ceramic powders—because the flexible inner mold cannot provide the necessary rigid support and shape constraint for the fluid ceramic powder. Therefore, developing a process that can directly use dry ceramic powder for isostatic pressing to prepare ceramic rollers is of great significance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an isostatic pressing method for ceramic rollers, which can directly use dry ceramic powder to perform isostatic pressing to obtain ceramic roller blanks, and has the advantages of simple process, short production cycle, convenient operation and accurate dimensions.

[0006] The technical problem to be solved by the present invention is to provide an isostatic pressing mold for ceramic rollers, which can realize the preparation of ceramic roller blanks by isostatic pressing using dry ceramic powder directly.

[0007] To address the aforementioned technical problems, this invention provides an isostatic pressing method for ceramic rollers, comprising: An elastically molded tube is inserted into a rigid inner support tube. Under no pressure, the elastically molded tube fits into the rigid inner support tube. The rigid inner support tube is provided with a through hole that penetrates the inner and outer tube walls. A rigid inner support tube fitted with an elastic molding tube is placed inside a rigid outer support tube, and a molding cavity is formed between the elastic molding tube and the rigid outer support tube. After sealing one end of the rigid outer support tube, ceramic powder is filled into the molding cavity, and the other end of the rigid outer support tube is sealed to obtain the first component assembly. The first component assembly is inserted into the flexible sealing tube and sealed to obtain the second component assembly; The second component assembly is subjected to isostatic pressing. The isostatic pressing medium applies radial pressure to the ceramic powder from the inside out through the elastic forming tube to obtain a ceramic roller blank tube. The ceramic roller blank, after being subjected to isostatic pressing, is depressurized and demolded, and then fired to obtain the ceramic roller.

[0008] As an improvement to the above technology, the moisture content of the ceramic powder is ≤5wt%; The raw materials of the ceramic powder, calculated by mass percentage, include 15wt%~25wt% kaolin, 10wt%~15wt% clay, 17wt%~25wt% alumina, 3wt%~10wt% zirconium silicate, and 30wt%~40wt% corundum sand.

[0009] As an improvement to the above technology, the rigid inner support tube is an integral rigid tube; The rigid inner support tube has several through holes in the area corresponding to the molded cavity, and the several through holes are evenly distributed on the rigid inner support tube. The total flow area of ​​the plurality of through holes is s, and the outer surface area of ​​the rigid inner support tube with the same diameter and no holes is S, wherein s / S≤0.2.

[0010] As an improvement to the above technology, both ends of the rigid outer support tube are designed as open structures; Both ends of the rigid inner support tube are designed to be open structures.

[0011] As an improvement to the above technology, before isostatic pressing, the inner diameter of the elastic forming tube is less than or equal to the outer diameter of the rigid inner support tube. The elastic molding tube and the rigid outer support tube have a first preset distance to form the molding cavity, and the first preset distance is d1, where d1 ≥ 10 mm.

[0012] As an improvement to the above technology, the elastic molded tube has a circular runout ≤0.3mm under pressure, a tensile strength ≥15MPa, an elongation at break ≥200%, a tensile strength change rate ≤±20%, and an elongation at break change rate ≤±40%.

[0013] As an improvement to the above technology, the elastic molded tube is made of a hydrophobic polymer material.

[0014] As an improvement to the above technology, the material of the elastic molded tube is selected from one or more of polyvinyl chloride, polyethylene, polypropylene, polybutadiene, thermoplastic polyurethane elastomer, thermoplastic elastomer, thermoplastic rubber, thermoplastic vulcanized rubber and chlorinated polyethylene.

[0015] As an improvement to the above technology, the flexible sealing tube is made of a flexible polymer material; The rigid inner support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic. The rigid outer support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic.

[0016] As an improvement to the above technology, the cross-sectional shape of the rigid outer support tube is circular, elliptical, or polygonal; The rigid external support pipe is formed by at least two external support components tightly bound together by fasteners, such as clamps, hose clamps, straps, buckles, or clips.

[0017] As an improvement to the above technology, the end of the rigid outer support tube is sealed by a first elastic sealing plug, which can achieve sealing by compressing and deforming the gap during isostatic pressure treatment. The first component assembly is fitted into the flexible sealing tube and sealed by the second elastic sealing plug. The second elastic sealing plug can achieve sealing by compressing and deforming the gap during isostatic pressure treatment.

[0018] As an improvement to the above technology, in the first component assembly, the first elastic sealing plug is sleeved on the outside of the elastic molded tube and partially inserted into the rigid outer support tube, and the inner wall of the first elastic sealing plug abuts against the elastic molded tube, and the outer wall of the first elastic sealing plug abuts against the rigid outer support tube, so as to seal the opening of the rigid outer support tube. The deformation rate of the first elastic sealing plug is less than that of the elastic molded tube.

[0019] As an improvement to the above technology, in the second component assembly, the second elastic sealing plug is located on the side of the first elastic sealing plug away from the molding cavity, and the second elastic sealing plug is sleeved on the outside of the elastic molding tube and located inside the flexible sealing tube. The inner wall of the second elastic sealing plug abuts against the elastic molded tube, and the outer wall of the second elastic sealing plug abuts against the flexible sealing tube to seal the opening of the flexible sealing tube. The deformation rate of the second elastic sealing plug is less than that of the elastic molded tube.

[0020] As an improvement to the above technology, the wall thickness of the rigid inner support tube, the elastically formed tube, the rigid outer support tube, and the flexible sealing tube is ≥1mm; The lengths of the rigid inner support tube, the elastic molded tube, the rigid outer support tube, and the flexible sealing tube are ≥1500mm.

[0021] Accordingly, the present invention also provides an isostatic pressing mold for ceramic rollers, using the above-described isostatic pressing method for ceramic rollers, comprising a rigid inner support tube, a rigid outer support tube, an elastic forming tube, a flexible sealing tube, a first elastic sealing plug, and a second elastic sealing plug. The elastic forming tube is sleeved outside the rigid inner support tube, and the rigid outer support tube is sleeved outside the elastic forming tube. A forming cavity for filling ceramic powder is provided between the elastic forming tube and the rigid outer support tube. The rigid inner support tube is provided with a through hole penetrating the inner and outer tube walls. The first elastic sealing plug is sleeved on the outside of the elastic molded tube, and the first elastic sealing plug is partially inserted into the rigid outer support tube. The first elastic sealing plug is used to seal the opening of the rigid outer support tube. The second elastic sealing plug is located on the side of the first elastic sealing plug away from the molded cavity, and the second elastic sealing plug is sleeved on the outside of the elastic molded tube and located inside the flexible sealing tube. The second elastic seal is used to seal the opening of the flexible sealing tube.

[0022] Implementing this invention has the following beneficial effects: This embodiment innovatively proposes an isostatic pressing method for ceramic rollers, enabling direct isostatic pressing of ceramic powder to form hollow ceramic roller blanks. Due to the use of rigid inner and outer support tubes, this isostatic pressing method ensures that the ceramic powder maintains good uniformity, roundness, and straightness within the forming cavity during filling. During isostatic pressing, the isostatic pressing medium first enters the interior of the rigid inner support tube and then enters the gap between the rigid inner support tube and the elastic forming tube through a through-hole. Because the elastic forming tube is elastic, the isostatic pressing medium causes it to expand, thereby uniformly applying radial pressure to the ceramic powder within the forming cavity, with the pressure direction outwards. During isostatic pressing, the rigid outer support tube provides stable rigid support force. Simultaneously, because the pressure transmission of the isostatic pressing medium is uniform, the elastic forming tube undergoes uniform radial expansion, which helps ensure the straightness and roundness of the ceramic roller blank. The ceramic roller blank produced by the isostatic pressing method of this embodiment has the characteristics of high density, high strength and good uniformity.

[0023] Furthermore, since the isostatic pressing method of this embodiment directly uses dry ceramic powder for isostatic pressing, it can simplify the process steps, reduce the difficulty of operation, and shorten the production cycle. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the isostatic pressing mold for ceramic rollers after being filled with ceramic powder, according to one embodiment of the present invention. Figure 2 yes Figure 1 A partially enlarged schematic diagram of the isostatic pressing mold in the embodiment shown; Figure 3 yes Figure 1 A schematic diagram of the rigid inner support tube in the isostatic pressing mold of the embodiment shown; Figure 4 This is a schematic diagram of the rigid inner support tube in an isostatic pressing mold according to another embodiment of the present invention; Figure 5 This is a photograph of a ceramic roller blank obtained by the isostatic pressing method for ceramic rollers according to Embodiment 1 of the present invention. Figure 6 This is a schematic diagram of the forming process of the ceramic roller blank in the isostatic pressing forming method for ceramic rollers in Example 1; Among them: rigid inner support tube 1, rigid outer support tube 2, elastic molding tube 3, flexible sealing tube 4, first elastic sealing plug 5, second elastic sealing plug 6, ceramic powder 7, molding cavity 8, fixing part 9, and through hole 11. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0026] Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Raw materials whose manufacturers are not specified are all commercially available conventional products.

[0027] like Figures 1 to 6 As shown, this embodiment provides an isostatic pressing method for ceramic rollers, including: An elastically formed tube 3 is inserted into a rigid inner support tube 1. In a pressureless state, the elastically formed tube 3 is in contact with the rigid inner support tube 1. The rigid inner support tube 1 is provided with a through hole 11 that penetrates the inner and outer tube walls, so that the isostatic medium can pass freely during isostatic pressure treatment. A rigid inner support tube 1 fitted with an elastic molding tube 3 is placed inside a rigid outer support tube 2, and a molding cavity 8 is formed between the elastic molding tube 3 and the rigid outer support tube 2. After sealing one end of the molding cavity 8, ceramic powder 7 is filled into the molding cavity 8, and then the other end of the molding cavity 8 is sealed to obtain the first component assembly. The first component assembly is inserted into the flexible sealing tube 4 and sealed to obtain the second component assembly (i.e., the second component assembly is obtained). Figure 1 (The structure shown) The second component assembly is subjected to isostatic pressing. The isostatic pressing medium applies radial pressure to the ceramic powder from the inside out through an elastic forming tube to obtain a ceramic roller blank. Specifically, the second component assembly filled with ceramic powder is placed in a high-pressure device for isostatic pressing. The isostatic pressing medium is a high-pressure fluid medium, which can be a gas (such as air or inert gas) or a liquid (such as oil or water). The working pressure of isostatic pressing is 50MPa~250MPa. After isostatic pressing, the obtained ceramic roller blank has the characteristics of high density, high strength and good uniformity, which can significantly reduce the firing shrinkage rate and breakage rate, and improve the product qualification rate. Preferably, the working pressure range of isostatic pressing is 80MPa~180MPa; the holding time can be set to 10s~120s, preferably 20s~30s; multiple isostatic pressing cycles can also be performed, preferably 1~3 times, and the pressure can be set to increase gradually during multiple isostatic pressing operations. The ceramic roller blank, after isostatic pressing, is depressurized and demolded, then fired to obtain the ceramic roller. In some embodiments, the firing temperature is 1530℃~1650℃, and the total firing time is 22h~36h. More preferably, the firing temperature is 1570℃~1600℃, and the total firing time is 24h~30h. The preferred holding time during firing is 4h~9h.

[0028] To address the current challenge in ceramic roller manufacturing, particularly the difficulty of directly isostatically pressing ceramic powder, especially for hollow ceramic rollers, there are no reports on the direct isostatic pressing of ceramic powder. Therefore, this embodiment innovatively proposes an isostatic pressing method suitable for ceramic rollers, enabling the direct isostatic pressing of ceramic powder to produce hollow ceramic roller blanks.

[0029] Specifically, the isostatic pressing method for ceramic rollers in this embodiment employs a rigid inner support tube and a rigid outer support tube, ensuring that the ceramic powder maintains good uniformity, roundness, and straightness within the forming cavity during filling. During isostatic pressing, the isostatic pressing medium (which can be a high-pressure fluid) first enters the interior of the rigid inner support tube and then passes through a through-hole into the gap between the rigid inner support tube and the elastic forming tube. Due to the elasticity of the elastic forming tube, the isostatic pressing medium causes it to expand, thereby uniformly applying radial pressure to the ceramic powder within the forming cavity, with the pressure direction outwards. During isostatic pressing, the rigid outer support tube provides stable rigid support. Because the pressure transmission of the isostatic pressing medium is uniform, the elastic forming tube undergoes uniform radial expansion, which helps ensure the straightness and roundness of the ceramic roller blank. The ceramic roller blanks formed by isostatic pressing according to this embodiment have the characteristics of high density, high strength and good uniformity. Furthermore, since dry ceramic powder is directly used for isostatic pressing, the process steps are simplified, the operation difficulty is reduced and the production cycle is shortened.

[0030] Further explanation: In the isostatic pressing method, a release agent can be used to assist in the demolding of the ceramic blank tube. The release agent can be an inorganic release agent (such as mica, clay, white clay, etc.) or an organic release agent (such as fatty acid soaps, fatty acids, paraffin wax, glycerin, petrolatum, etc.); preferably, the release agent can be a fatty acid soap-based release agent (such as ammonium soap, potassium soap, potassium soap, and zinc soap, etc.). This fatty acid soap-based release agent, such as potassium soap, needs to be dissolved in hot water and repeatedly applied to the inner wall of the rigid outer support tube, and can be used after it dries.

[0031] To further explain, after the ceramic powder is filled, it can be compacted by tamping or vibrating, preferably by vibrating, which can be done using a vibrating table with a fixing device.

[0032] In one embodiment, the moisture content of the ceramic powder is ≤5wt%, making the ceramic powder a dry granular powder. More preferably, the moisture content of the ceramic powder is 0~3wt%. If the moisture content of the ceramic powder exceeds 5wt%, it needs to be dried to control the moisture content of the ceramic powder below 5wt%. Microwave drying or hot air drying in a drying room can be selected.

[0033] In one embodiment, the raw materials of the ceramic powder, calculated by mass percentage, include 15wt%~25wt% kaolin, 10wt%~15wt% clay, 17wt%~25wt% alumina, 3wt%~10wt% zirconium silicate, and 30wt%~40wt% corundum sand. It should be noted that the ceramic powder of the present invention can also use existing formulations for preparing ceramic rollers, provided that the moisture content of the ceramic powder is controlled to be ≤5wt%.

[0034] In one embodiment, a small amount of binder can be added to the ceramic powder to assist in molding, wherein the amount of binder added is 0-2 wt%. The binder can be a binder commonly used in the preparation of ceramic rollers, and can be a natural product, such as starch, gum arabic, tung oil or paraffin; or a chemically synthesized compound, such as polyvinyl alcohol, carboxymethyl cellulose or phenolic resin, but is not limited thereto.

[0035] In one embodiment, the rigid inner support tube is an integral rigid tube. The rigid inner support tube has a plurality of through holes in the area corresponding to the forming cavity, that is, through holes are provided in the area where ceramic powder is filled, and the plurality of through holes are evenly distributed on the rigid inner support tube; in one embodiment, multiple through holes are evenly arranged in the middle section of the rigid inner support tube along the axial direction of the rigid inner support tube, while the two ends of the rigid inner support tube may not have through holes. The total flow area of ​​the plurality of through holes is s, and the outer surface area of ​​the rigid inner support tube with the same diameter and no holes is S, wherein s / S≤0.2.

[0036] Further explanation: the through-hole is exemplarily a circular hole or a slit hole, but is not limited to these, as long as the isostatic medium (high-pressure fluid medium) can pass smoothly through the through-hole. In addition, the area of ​​the through-hole should not be too large to avoid affecting the mechanical strength of the rigid inner support tube. In some embodiments, the ratio of the flow area of ​​several through-holes to the outer surface area of ​​the rigid inner support tube of the same diameter without holes is ≤0.2, exemplarily 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, or 0.20, but is not limited to these.

[0037] Specifically, the flow area refers to the cross-sectional area through which fluids (such as gases or liquids) can freely pass through components such as pipes, valves, and through holes. In this invention, the total flow area of ​​the plurality of through holes is the sum of the areas of the plurality of through holes. The non-perforated pipe with the same diameter as the rigid inner support pipe is a support pipe without through holes, and the outer and inner diameters of the support pipe are equal to the outer and inner diameters of the rigid inner support pipe of this invention.

[0038] In one embodiment, both ends of the rigid outer support tube are designed as open structures to facilitate subsequent demolding. If one end of the rigid outer support tube is closed and only one end is left open for ceramic powder filling, demolding will be very difficult.

[0039] In one embodiment, both ends of the rigid inner support tube are designed as open structures, so that during isostatic pressing, the high-pressure fluid medium can enter the interior of the rigid inner support tube through the openings at both ends of the rigid inner support tube and flow through the through holes of the rigid inner support tube to apply pressure to the elastically formed tube.

[0040] In one embodiment, before isostatic pressing (i.e., under unpressurized conditions), the inner diameter of the elastically formed tube is less than or equal to the outer diameter of the rigid inner support tube. The elastic molding tube and the rigid outer support tube have a first preset distance to form the molding cavity, and the first preset distance is d1, where d1≥10mm; The elastic forming tube needs to fit snugly against the rigid inner support tube when not under stress, and there should be sufficient space between it and the rigid outer support tube to ensure that the ceramic powder is uniform and of the same thickness throughout. Furthermore, to ensure the strength of the ceramic roller blank tube, the wall thickness of the ceramic roller blank tube must be ≥3mm. By limiting the first preset distance d1 between the elastic forming tube and the rigid outer support tube to ≥10mm, and performing isostatic pressing on the ceramic powder, a ceramic roller blank tube with a wall thickness of ≥3mm can be obtained.

[0041] Preferably, the wall thickness of the ceramic roller blank tube is 3mm to 15mm, and the outer diameter of the ceramic roller blank tube is 15mm to 70mm. The first preset distance can be adjusted according to the required wall thickness of the ceramic roller blank tube. Specifically, the first preset distance can be adjusted by replacing the rigid inner support tube and the rigid outer support tube with different sizes, and by selecting a suitable elastic forming tube and a flexible sealing tube. It is worth noting that the wall thickness of the ceramic roller blank tube obtained by the present invention is only one preferred embodiment, and the thickness of the ceramic roller blank tube can be adjusted according to actual needs.

[0042] In one embodiment, the flexible sealing tube can be made of plastic or rubber. The flexible sealing tube needs to have a certain degree of deformability and be waterproof during isostatic pressing.

[0043] Furthermore, the elastically molded tube is required to possess excellent elasticity, capable of fully expanding without leakage of the isostatic medium during isostatic pressing, and able to recover its shape after depressurization to meet the requirement of reusability. Therefore, the elastically molded tube is preferably made of a polymer material with a tensile strength ≥15MPa and an elongation at break ≥200%. Preferably, the polymer material used has a tensile strength change rate ≤±20% and an elongation at break ≤±40% after aging, meaning that the change in tensile strength after aging does not exceed 20% of the original value, and the change in elongation at break does not exceed 40% of the original value.

[0044] In one embodiment, the circular runout of the elastic forming tube under pressure is ≤0.3mm, so as to further ensure the straightness and uniformity of the ceramic roller blank tube.

[0045] In one embodiment, the elastically molded tube is made of a hydrophobic polymer material. Due to its low surface energy, the hydrophobic polymer material is difficult to form hydrogen bonds or adsorb with water molecules, resulting in water difficulty spreading on its surface and a large contact angle, thus exhibiting significant water repellency. This characteristic effectively prevents water penetration into the elastically molded tube. In addition to hydrophobicity, the polymer material used in the elastically molded tube has a dense physical structure; the tightly packed molecular chains and low free volume fraction result in small and low-density micro-gap sizes generated during elastic expansion and deformation, effectively blocking the penetration of fluid molecules such as water molecules.

[0046] Preferably, the hydrophobic polymer material can be made of rubber and soft plastic. The excellent elasticity and waterproof properties of rubber can better achieve isostatic pressing. In addition, soft plastic also has good elasticity and waterproof properties.

[0047] In one embodiment, the material of the elastic molded tube is selected from one or more of polyvinyl chloride (PVC), polyethylene, polypropylene, polybutadiene, thermoplastic polyurethane elastomer (TPU), thermoplastic elastomer (TPE), thermoplastic rubber (TPR), thermoplastic vulcanized rubber (TPV), and chlorinated polyethylene (CPE).

[0048] These polymer materials have good water resistance, elasticity and dense physical structure. During isostatic pressing, the elastically molded tube undergoes elastic expansion deformation, which increases the spacing between polymer chains inside the polymer material. If the density of the polymer material used is low, larger micro-gaps will be generated during the elastic expansion deformation process, which will increase the possibility of water penetrating into the molding cavity.

[0049] In one embodiment, the flexible sealing tube is made of a flexible polymer material; preferably, the flexible polymer material is rubber and / or flexible plastic. The performance requirements for the flexible sealing tube are lower than those for the elastic molded tube, only requiring compliance with flexibility and deformation and no leakage of fluid media during isostatic pressing. Furthermore, the flexible polymer material can also be the same as that used for the elastic molded tube, such as the aforementioned TPU, TPE, TPR, TPV, and CPE, but is not limited to these.

[0050] The rigid inner support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic. The material of the rigid outer support tube needs to have small deformation and certain strength under isostatic pressure. Preferably, the rigid outer support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic.

[0051] The rigid inner support tube and rigid outer support tube are made of materials that have good strength and rigidity. When filling ceramic powder, they can ensure that the ceramic powder is filled evenly and that the thickness is equal everywhere, thereby ensuring the roundness, straightness and mechanical strength of the ceramic roller blank tube.

[0052] The rigid inner support tube and the rigid outer support tube are preferably made of metal tubes because metal materials have high strength, low deformation, and are easy to process, providing better stable rigid support during use to ensure the roundness and straightness of the ceramic roller blank tube. The rigid inner support tube and the rigid outer support tube can be made of materials such as stainless steel, iron, and aluminum, but are not limited to these. It should be noted that other rigid materials, such as ceramics, hard plastics, and glass, can also be used for the rigid inner support tube and the rigid outer support tube, and the implementation is not limited to the embodiments described in this invention.

[0053] Furthermore, depending on the requirements of the ceramic roller, the rigid outer support tube can be configured in various different shapes to facilitate molding. In some embodiments, the cross-sectional shape of the rigid outer support tube 2 is circular, elliptical, or polygonal; examples of polygons include rectangles, hexagons, or octagons, but are not limited thereto. The cross-sectional shape of the rigid inner support tube can correspond to the cross-sectional shape of the rigid outer support tube; additionally, the cross-sectional shape of the rigid inner support tube can also be fixedly set as circular. The rigid outer support tube 2 is formed by at least two outer support components tightly bound together by fasteners 9, which is beneficial for subsequent demolding. The fasteners 9 are clamps, hose clamps, band clamps, cable ties, buckles or clips, which are easy to disassemble and install.

[0054] In one embodiment, the rigid outer support tube 2 includes two outer support members, both of which have a semi-circular cross section. The two outer support members are joined together to form a cylindrical rigid outer support tube.

[0055] In one embodiment, the end of the rigid outer support tube is sealed by a first elastic sealing plug 5, which can achieve sealing by compressing and deforming the gap during isostatic pressure treatment.

[0056] In one embodiment, in the first component assembly, the first elastic sealing plug is sleeved on the outside of the elastic molded tube and partially inserted into the rigid outer support tube, and the inner wall of the first elastic sealing plug abuts against the elastic molded tube, and the outer wall of the first elastic sealing plug abuts against the rigid outer support tube to seal the opening of the rigid outer support tube. The deformation rate of the first elastic sealing plug is less than that of the elastic forming tube, ensuring that the ceramic powder remains in the forming cavity during isostatic pressing to form a ceramic roller blank with good roundness and straightness.

[0057] Specifically, the first elastic sealing plug has a first limiting hole (not shown in the figure) through which the rigid inner support tube containing the elastic molded tube passes. The first elastic sealing plug is partially inserted into the rigid outer support tube, and is sleeved on the outside of the rigid inner support tube containing the elastic molded tube, thereby sealing the rigid outer support tube. During isostatic pressing, the high-pressure fluid medium applies radial pressure from the inside to the outside to the elastic molded tube, which can make the inner wall of the first elastic sealing plug (i.e., the wall of the first limiting hole) and the elastic molded tube fit tightly together, and the outer wall of the first elastic sealing plug and the rigid outer support tube fit tightly together, so that the molding cavity forms a sealed cavity and prevents ceramic powder leakage.

[0058] Preferably, the first elastic sealing plug has a T-shaped structure, with the thin end facing inward and the thick end facing outward, and is used to confine the ceramic powder within the molding cavity to prevent leakage.

[0059] The preferred material for the first elastic sealing plug is plastic, rubber, or solid wood.

[0060] In one embodiment, the first component assembly is fitted into the flexible sealing tube 4 and sealed by the second elastic sealing plug 6, which can achieve sealing by compressing and deforming the gap during isostatic pressure treatment.

[0061] In one embodiment, in the second component assembly, the second elastic sealing plug is located on the side of the first elastic sealing plug away from the molded cavity, and the second elastic sealing plug is sleeved on the outside of the elastic molded tube and located inside the flexible sealing tube. The inner wall of the second elastic sealing plug abuts against the elastic molded tube, and the outer wall of the second elastic sealing plug abuts against the flexible sealing tube to seal the opening of the flexible sealing tube. The deformation rate of the second elastic sealing plug is less than that of the elastic molded tube.

[0062] Specifically, the second elastic sealing plug is hollow inside and has a second limiting hole (not shown in the figure). During installation, the second elastic sealing plug is installed inside the end of the flexible sealing tube, and the second elastic sealing plug is sleeved on the outside of the rigid inner support tube with the elastic molding tube, and the second elastic sealing plug is located on the side of the first elastic sealing plug away from the molding cavity. During isostatic pressing, since the entire second component assembly is placed in a high-pressure fluid medium, the pressurization effect of the isostatic pressing equipment causes the high-pressure fluid medium to pressurize the second elastic sealing plug through the flexible sealing tube. Under the external pressure and the elasticity of the second elastic sealing plug itself, the flexible sealing tube, the second elastic sealing plug and the elastic molding tube are tightly fitted together, so that the inside of the flexible sealing tube is always sealed, which can prevent the high-pressure fluid medium from entering the inside of the flexible sealing tube and contacting the ceramic powder or ceramic roller blank tube. In addition, during the isostatic pressing process, the high-pressure fluid medium also applies pressure to the side of the second elastic sealing plug away from the ceramic powder. The direction of this pressure is towards the ceramic powder, which causes the second elastic sealing plug to press against the first elastic sealing plug, preventing the first elastic sealing plug from shifting. This ensures that during isostatic pressing, the ceramic powder will only move radially and will not move axially, thereby forming a ceramic roller blank tube of uniform thickness and density.

[0063] In one embodiment, the inner diameter of the flexible sealing tube is less than the outer diameter of the second elastic sealing plug, which expands the flexible sealing tube during assembly to generate an inward radial contraction force to achieve a seal.

[0064] The second elastic sealing plug needs to be elastic, deforming under isostatic pressure to close the gaps between the flexible sealing tube and the elastically molded tube. Regarding materials, the second elastic sealing plug can be made of rubber or plastic, preferably rubber. The function of the second elastic sealing plug is to use the pressure of a high-pressure fluid medium during isostatic pressing to ensure tight contact between the flexible sealing tube, the elastically molded tube, and the rigid inner support tube, thus closing the gaps. This effectively prevents the high-pressure fluid medium from entering from both ends and directly contacting the ceramic blank tube.

[0065] In one embodiment, the wall thickness of the rigid inner support tube, the elastic forming tube, the rigid outer support tube, and the flexible sealing tube is ≥1mm, preferably within the range of 1mm to 5mm. If the wall thickness of the material is too large, it will increase the weight of the forming mold, which is not conducive to manual operation; if the wall thickness is too thin, it will reduce the strength of the rigid inner support tube and the rigid outer support tube, making them prone to deformation. If the wall thickness of the elastic forming tube and the flexible sealing tube is too thin, they are prone to breakage and leakage. All of these will affect the forming qualification rate and dimensional accuracy of the ceramic roller blank tube.

[0066] In one embodiment, the lengths of the rigid inner support tube, the elastically molded tube, the rigid outer support tube, and the flexible sealing tube are all ≥1500mm. Preferably, the lengths of the rigid inner support tube, the elastically molded tube, the rigid outer support tube, and the flexible sealing tube are 1500mm~7000mm respectively.

[0067] Preferably, the central axes of the rigid inner support tube, the elastic forming tube, the rigid outer support tube, and the flexible sealing tube coincide, that is, they have the same central axis, which is conducive to uniform forming and allows the ceramic roller to shrink uniformly during the firing process, ensuring the straightness and roundness of the ceramic roller, thereby ensuring that the product has a qualified appearance.

[0068] It is worth noting that the entire workflow of the isostatic pressing method for ceramic rollers in this embodiment is as follows: The second component assembly filled with ceramic powder is placed in a high-pressure device for isostatic pressing. The high-pressure device contains an isostatic pressing medium, which is a high-pressure fluid medium. That is, the entire second component assembly is placed in the isostatic pressing fluid medium. During the isostatic pressing process, the fluid medium enters the rigid inner support tube from the openings at both ends of the rigid inner support tube and flows into the gap between the rigid inner support tube and the elastic forming tube through the through holes of the rigid inner support tube. Since the pressure of the high-pressure fluid medium is as high as 50MPa~250MPa, and the elastic forming tube is elastic, the elastic forming tube expands due to the action of the high-pressure fluid medium. The high-pressure fluid medium applies uniform radial pressure to the ceramic powder in the forming cavity through the elastic forming tube, with the pressure direction outward. This causes the ceramic powder to deform or rearrange particles under high pressure, eliminating internal pores, improving density and uniformity, and forming a ceramic roller blank. On the other hand, since the second component assembly is entirely immersed in a high-pressure fluid medium, the high-pressure fluid medium also applies pressure from the outside to the inside to the flexible sealing tube. This ensures that during isostatic pressing, the flexible sealing tube is tightly fitted to the surface of the rigid outer support tube, applying pressure from the outside to the inside to the rigid outer support tube. Furthermore, since the second elastic sealing plug is fitted at the end of the flexible sealing tube, with its outer side in contact with the flexible sealing tube and its inner side in contact with the elastic forming tube, the high-pressure fluid medium also applies pressure from the outside to the inside to the second elastic sealing plug through the flexible sealing tube. By utilizing the pressure of the high-pressure fluid medium, the flexible sealing tube, the second elastic sealing plug, the elastic forming tube, and the rigid inner support tube are brought into close contact to seal any gaps. This effectively prevents the high-pressure fluid medium from seeping into the interior of the flexible sealing tube from both ends, thus avoiding the high-pressure fluid medium affecting the integrity of the ceramic roller blank. After isostatic pressing for a specified time, a ceramic roller blank with high density, high strength, and good uniformity can be formed, significantly reducing the firing shrinkage rate and breakage rate, and improving the product qualification rate. After firing, ceramic rollers can be obtained.

[0069] Accordingly, this embodiment also provides an isostatic pressing mold for ceramic rollers, using the above-described isostatic pressing method for ceramic rollers, including a rigid inner support tube 1, a rigid outer support tube 2, an elastic forming tube 3, a flexible sealing tube 4, a first elastic sealing plug 5, and a second elastic sealing plug 6. The elastic molded tube sleeve 3 is disposed outside the rigid inner support tube 1, and the rigid outer support tube sleeve 2 is disposed outside the elastic molded tube 3. A molded cavity 8 for filling ceramic powder 7 is formed between the elastic molded tube 3 and the rigid outer support tube 2. The rigid inner support tube 1 is provided with a through hole 11 penetrating the inner and outer tube walls. The first elastic sealing plug 5 is sleeved on the outside of the elastic molded tube 3, and the first elastic sealing plug 5 is partially inserted into the rigid outer support tube 2. The first elastic sealing plug 5 is used to seal the opening of the rigid outer support tube 2. The second elastic sealing plug 6 is located on the side of the first elastic sealing plug 5 away from the molded cavity 8, and the second elastic sealing plug 6 is sleeved on the outside of the elastic molded tube 3 and located inside the flexible sealing tube 4. The second elastic seal 6 is used to seal the opening of the flexible sealing tube 4.

[0070] The isostatic pressing mold of this embodiment enables the direct isostatic pressing of ceramic dry powder to prepare ceramic roller blanks. Due to the combination of a rigid inner support tube and a rigid outer support tube, the ceramic powder maintains a uniform thickness throughout the mold during filling, ensuring good roundness and straightness. The high-pressure fluid medium causes the elastic forming tube to expand, uniformly applying radial pressure to the ceramic powder outwards. During isostatic pressing, the rigid outer support tube provides stable rigid support. Simultaneously, because the pressure transmission of the high-pressure fluid medium is uniform, the elastic forming tube undergoes uniform radial expansion, which helps ensure the straightness and roundness of the ceramic roller blank.

[0071] Preferably, the sidewalls and bottom surfaces of the second elastic sealing plug, as well as the sidewalls and top surfaces of the second elastic sealing plug, are rounded, so that the outer edge of the second elastic sealing plug is not right-angled but has a rounded structure. This not only allows the second elastic sealing plug to be quickly wedged into the flexible sealing tube, but also makes the shape transition of the flexible sealing tube smooth during isostatic pressing, with small deformation amplitude and long service life.

[0072] The technical solution of the present invention is further described below through embodiments.

[0073] Example 1 Weigh out the raw materials required for manufacturing ceramic powder: 25wt% kaolin, 15wt% clay, 17wt% alumina, 3wt% zirconium silicate, and 40wt% corundum sand. Place these raw materials in a ball mill and ball mill for 2 hours to obtain a slurry. Then, pour the slurry into a slurry tank and mix it thoroughly with a high-powered mixer to obtain a mud. Next, transport the mud to a spray drying tower for spray granulation treatment. Use the granulation process to improve the flowability of the powder to obtain dry powder. Add 2wt% carboxymethyl cellulose as a binder to the dry powder and add 2wt% water for mixing to assist in molding. Finally, obtain ceramic powder with a water content of 2wt%.

[0074] First, apply two coats of potassium soap release agent dissolved in hot water to the inner wall of the rigid outer support tube. After drying, insert the rigid inner support tube (with a through hole, which is round) into the elastic molded tube. Next, use clamps as fasteners to fix the components of the rigid outer support tube, and then place the rigid inner support tube with the elastic molded tube inside the rigid outer support tube. Insert a first elastic sealing plug into one end of the rigid outer support tube. After filling with pre-prepared ceramic powder, compact it using a vibrating table with a fixing device. After multiple filling and compaction cycles, insert another first elastic sealing plug into the open end of the rigid outer support. Then, insert it into the flexible sealing tube, and insert second elastic sealing plugs into both ends of the flexible sealing tube. Among them, the rigid inner and outer support tubes are made of stainless steel with a wall thickness of 2mm; the elastic molding tube is made of high-performance rubber with a wall thickness of 2mm; the first elastic sealing plug is made of flexible plastic; the flexible sealing tube is made of rubber with a wall thickness of 2mm; the rigid outer support tube is 2000mm long and has an outer diameter of 74mm; the rigid inner support tube is 2100mm long and has an outer diameter of 45mm.

[0075] The isostatic pressing mold filled with ceramic powder is placed in a cold isostatic press and subjected to isostatic pressing at a pressure of 180 MPa for 20 seconds. The isostatic pressing medium is water, resulting in a ceramic roller blank tube.

[0076] The ceramic roller blank, after being subjected to isostatic pressing, is depressurized and demolded, then dried in a drying room for 1 day. Finally, it is placed in a kiln and fired at 1600℃ for a total firing time of 30 hours. After cooling to room temperature, the ceramic roller is obtained.

[0077] like Figure 5 As shown, the ceramic roller blank obtained after isostatic pressing in this embodiment has excellent roundness and straightness.

[0078] Example 2 Weigh out the raw materials required for manufacturing ceramic powder: 25 wt% kaolin, 15 wt% clay, 25 wt% alumina, 5 wt% zirconium silicate, and 30 wt% corundum sand. Put these raw materials into a ball mill and ball mill for 2 hours to obtain a slurry. Then pour the slurry into a slurry tank and stir it thoroughly with a high-powered mixer to obtain a mud. Finally, transport the mud to a spray drying tower for spray granulation treatment to obtain a dry powder with high fluidity, which is the ceramic powder. An elastically molded tube (with a through hole, which is round) is inserted into the outside of the rigid inner support tube. Then, the components of the rigid outer support tube are fixed with wire. Next, the rigid inner support tube, with the elastically molded tube inside, is placed inside the rigid outer support tube. Then, a first elastic sealing plug is inserted into one end of the rigid outer support tube. After filling with pre-prepared ceramic powder, it is compacted using a vibrating table with a fixing device. After multiple filling and compaction cycles, another first elastic sealing plug is inserted into the open end of the rigid outer support tube. After inserting it into a flexible sealing tube, second elastic sealing plugs are inserted into both ends of the flexible sealing tube. The rigid inner and outer support tubes are made of stainless steel with a wall thickness of 2 mm; the elastically molded tube is made of rubber with a wall thickness of 2 mm; the first elastic sealing plug is made of flexible plastic; and the flexible sealing tube is made of rubber with a wall thickness of 2 mm. The rigid outer support tube is 2000 mm long and has an outer diameter of 74 mm; while the rigid inner support tube is 2100 mm long and has an outer diameter of 45 mm.

[0079] The above apparatus is placed in a cold isostatic press and subjected to isostatic pressing at a pressure of 180 MPa for 30 seconds. The isostatic pressing medium is oil, resulting in ceramic roller blanks.

[0080] Next, the ceramic roller blank that has undergone isostatic pressing is depressurized and demolded, and then placed in a kiln for sintering at 1570℃ for a total firing time of 26 hours. Finally, the ceramic roller is obtained after cooling to room temperature.

[0081] Example 3 Weigh out the raw materials required for manufacturing ceramic powder: 15 wt% kaolin, 15 wt% clay, 22 wt% alumina, 8 wt% zirconium silicate, and 40 wt% corundum sand. Place these raw materials into a ball mill and ball mill for 2 hours to obtain a slurry. Then pour the slurry into a slurry tank and stir it thoroughly in a high-power mixer to obtain a mud. Next, transport the mud to a spray drying tower for spray granulation to obtain dry powder. Finally, add 2 wt% carboxymethyl cellulose as a binder to the dry powder and add 4 wt% water to mix the dry powder to obtain ceramic powder.

[0082] First, apply two coats of potassium soap release agent dissolved in hot water evenly to the inner wall of the rigid outer support tube. After drying, insert the rigid inner support tube (with a through hole, which is round) into the elastic molded tube. Then, use clamps to fix the components of the rigid outer support tube, and place the rigid inner support tube with the elastic molded tube inside the rigid outer support tube. Next, insert a first elastic sealing plug into one end of the rigid outer support tube. Then, fill with pre-prepared ceramic powder and compact it using a vibrating table with a fixing device. After multiple filling and compaction operations, insert another first elastic sealing plug into the other open end of the rigid outer support tube. Finally, after inserting the flexible sealing tube, insert second elastic sealing plugs into both ends of the flexible sealing tube. The rigid inner and outer support tubes are made of stainless steel with a wall thickness of 2 mm; the elastic molded tube is made of rubber with a wall thickness of 2 mm; the first elastic sealing plugs are made of flexible plastic; and the flexible sealing tube is made of rubber with a wall thickness of 2 mm. The rigid outer support tube has a length of 2000 mm and an outer diameter of 74 mm; the rigid outer support tube has a length of 2100 mm and an outer diameter of 45 mm.

[0083] The above apparatus was placed in a cold isostatic press and subjected to three isostatic pressing processes at 50 MPa, 100 MPa, and 150 MPa, respectively, with each pressure held for 20 seconds. Pressure was then applied again after complete depressurization. Water was used as the isostatic pressing medium. The isostatically pressed ceramic roller blanks were then depressurized and demolded, dried in a drying room for one day, and finally fired in a kiln at 1600℃ for a total firing time of 30 hours. After cooling to room temperature, the ceramic rollers were obtained.

[0084] Example 4 The raw materials required for manufacturing ceramic powder include 25 wt% kaolin, 10 wt% clay, 25 wt% alumina, 10 wt% zirconium silicate, and 30 wt% corundum sand. The above raw materials are put into a ball mill and ball-milled for 2 hours to obtain a slurry. The slurry is then poured into a slurry tank and thoroughly stirred with a high-powered mixer to obtain a mud. The mud is then transported to a spray drying tower for spray granulation to obtain dry powder. Finally, 1 wt% carboxymethyl cellulose is added to the dry powder as a binder, and 0.5 wt% water is added to mix the dry powder to obtain ceramic powder.

[0085] First, a potassium soap release agent dissolved in hot water is applied to the inner wall of the rigid outer support tube. After drying, the rigid inner support tube (with a through hole, which is a slit) is inserted into the elastic molded tube. Then, the rigid outer support tube is fixed with metal cable ties, and the rigid inner support tube with the elastic molded tube is placed inside the rigid outer support tube. A first elastic sealing plug is inserted into one end of the rigid outer support tube. Pre-prepared ceramic powder is then filled and compacted using a vibrating table with a fixing device. After multiple fillings and compactions, another first elastic sealing plug is inserted into the other open end of the rigid outer support tube. Finally, it is inserted into the flexible sealing tube, and second elastic sealing plugs are inserted into both ends of the flexible sealing tube. The rigid inner / outer support tubes are made of stainless steel with a wall thickness of 2 mm; the elastic molded tube is a rubber tube with a wall thickness of 2 mm; the first elastic sealing plugs are made of flexible plastic; and the flexible sealing tube is made of rubber with a wall thickness of 2 mm. The rigid outer support tube is 2000 mm long and 74 mm in outer diameter; the rigid outer support tube is 2100 mm long and 45 mm in outer diameter.

[0086] The above apparatus was placed in a cold isostatic press and subjected to isostatic pressing at a pressure of 150 MPa for 20 seconds. The isostatic pressing medium was water. After isostatic pressing, the ceramic roller blank was depressurized and demolded, then dried in a drying room for one day. Finally, it was placed in a kiln and fired at 1600℃ for a total firing time of 30 hours. After cooling to room temperature, the ceramic roller was obtained.

[0087] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention are still within the scope of the present invention.

Claims

1. A method for isostatic pressing of ceramic rollers, characterized in that, include: An elastically molded tube is inserted into a rigid inner support tube. Under no pressure, the elastically molded tube fits into the rigid inner support tube. The rigid inner support tube is provided with a through hole that penetrates the inner and outer tube walls. A rigid inner support tube fitted with an elastic molding tube is placed inside a rigid outer support tube, forming a molding cavity between the elastic molding tube and the rigid outer support tube. After sealing one end of the rigid outer support tube, ceramic powder is filled into the molding cavity, and the other end of the rigid outer support tube is sealed to obtain the first component assembly. The first component assembly is inserted into the flexible sealing tube and sealed to obtain the second component assembly; The second component assembly is subjected to isostatic pressing. The isostatic pressing medium applies radial pressure to the ceramic powder from the inside out through the elastic forming tube to obtain a ceramic roller blank tube. The ceramic roller blank, after being subjected to isostatic pressing, is depressurized and demolded, and then fired to obtain the ceramic roller.

2. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The moisture content of the ceramic powder is ≤5wt%; The raw materials of the ceramic powder, calculated by mass percentage, include 15wt%~25wt% kaolin, 10wt%~15wt% clay, 17wt%~25wt% alumina, 3wt%~10wt% zirconium silicate, and 30wt%~40wt% corundum sand.

3. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The rigid inner support tube is an integral rigid tube; The rigid inner support tube has a plurality of through holes in the area corresponding to the molded cavity, and the plurality of through holes are evenly distributed on the rigid inner support tube. The total flow area of ​​the plurality of through holes is s, and the outer surface area of ​​the rigid inner support tube with the same diameter and no holes is S, wherein s / S≤0.

2.

4. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, Both ends of the rigid external support tube are designed to be open structures; Both ends of the rigid inner support tube are designed to be open structures.

5. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, Before isostatic pressing, the inner diameter of the elastically formed tube is less than or equal to the outer diameter of the rigid inner support tube. The elastic molding tube and the rigid outer support tube have a first preset distance to form the molding cavity, and the first preset distance is d1, where d1 ≥ 10 mm.

6. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The elastically formed tube has a circular runout ≤0.3mm under pressure, a tensile strength ≥15MPa, an elongation at break ≥200%, a tensile strength change rate ≤±20%, and an elongation at break change rate ≤±40%.

7. The isostatic pressing method for ceramic rollers as described in claim 5, characterized in that, The elastic molded tube is made of hydrophobic polymer material.

8. The isostatic pressing method for ceramic rollers as described in claim 6, characterized in that, The material of the elastic molded tube is selected from one or more of the following: polyvinyl chloride, polyethylene, polypropylene, polybutadiene, thermoplastic polyurethane elastomer, thermoplastic elastomer, thermoplastic rubber, thermoplastic vulcanized rubber, and chlorinated polyethylene.

9. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The flexible sealing tube is made of flexible polymer material; The rigid inner support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic. The rigid outer support tube is a single-layer tube or composite tube made of metal, ceramic, glass or hard plastic.

10. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The cross-sectional shape of the rigid external support tube is circular, elliptical, or polygonal; The rigid external support pipe is formed by at least two external support components tightly bound together by fasteners, such as clamps, hose clamps, straps, buckles, or clips.

11. The isostatic pressing method for ceramic rollers as described in claim 1, characterized in that, The end of the rigid outer support tube is sealed by a first elastic sealing plug, which can achieve sealing by compressing and deforming the gap during isostatic pressure treatment. The first component assembly is fitted into the flexible sealing tube and sealed by the second elastic sealing plug. The second elastic sealing plug can achieve sealing by compressing and deforming the gap during isostatic pressure treatment.

12. The isostatic pressing method for ceramic rollers as described in claim 11, characterized in that, In the first component assembly, the first elastic sealing plug is sleeved on the outside of the elastic molded tube and partially inserted into the rigid outer support tube. The inner wall of the first elastic sealing plug abuts against the elastic molded tube, and the outer wall of the first elastic sealing plug abuts against the rigid outer support tube to seal the opening of the rigid outer support tube. The deformation rate of the first elastic sealing plug is less than that of the elastic molded tube.

13. The isostatic pressing method for ceramic rollers as described in claim 11, characterized in that, In the second component assembly, the second elastic sealing plug is located on the side of the first elastic sealing plug away from the molded cavity, and the second elastic sealing plug is sleeved on the outside of the elastic molded tube and located inside the flexible sealing tube; The inner wall of the second elastic sealing plug abuts against the elastic molded tube, and the outer wall of the second elastic sealing plug abuts against the flexible sealing tube to seal the opening of the flexible sealing tube. The deformation rate of the second elastic sealing plug is less than that of the elastic molded tube.

14. The isostatic pressing method for ceramic rollers as described in claim 11, characterized in that, The wall thickness of the rigid inner support tube, the elastic forming tube, the rigid outer support tube, and the flexible sealing tube is ≥1mm; The lengths of the rigid inner support tube, the elastic molded tube, the rigid outer support tube, and the flexible sealing tube are ≥1500mm.

15. An isostatic pressing mold for ceramic rollers, characterized in that, The isostatic pressing method for ceramic rollers according to any one of claims 1-14 includes a rigid inner support tube, a rigid outer support tube, an elastic forming tube, a flexible sealing tube, a first elastic sealing plug, and a second elastic sealing plug. The elastic forming tube is sleeved outside the rigid inner support tube, and the rigid outer support tube is sleeved outside the elastic forming tube. A forming cavity for filling ceramic powder is formed between the elastic forming tube and the rigid outer support tube. The rigid inner support tube is provided with a through hole penetrating the inner and outer tube walls. The first elastic sealing plug is sleeved on the outside of the elastic molded tube, and the first elastic sealing plug is partially inserted into the rigid outer support tube. The first elastic sealing plug is used to seal the opening of the rigid outer support tube. The second elastic sealing plug is located on the side of the first elastic sealing plug away from the molded cavity, and the second elastic sealing plug is sleeved on the outside of the elastic molded tube and located inside the flexible sealing tube. The second elastic seal is used to seal the opening of the flexible sealing tube.

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