CN-121973331-A - Isostatic pressing mold and method for ceramic long tube

Abstract

The invention discloses an isostatic pressing mould and method for a ceramic long tube, and aims to solve the defect that straightness of a product cannot be guaranteed when a ceramic tube with a longer length and a larger length-diameter ratio is processed. The invention comprises a hard core rod and an elastic die sleeve, wherein the two ends of the die sleeve are connected with end covers, the core rod is connected between the two end covers, the core rod is arranged in the die sleeve, a molding die cavity is formed between the core rod and the die sleeve, and a hard porous supporting tube is sleeved outside the die sleeve. In the isostatic compaction process of the ceramic long tube, the porous supporting tube with the added outer layer can increase the geometric stability of the mould at the initial stage of isostatic compaction, and the pressure is more uniformly distributed in the axial direction and the radial direction of the formed body at the initial stage of densification, so that the good straightness and uniform density of the subsequent formed body are ensured.

Inventors

• LEI MIN
• CAI DEQI
• LI YUNLONG

Assignees

• 杭州大和江东新材料科技有限公司

Dates

Publication Date

20260505

Application Date

20251121

Claims (10)

1. 1. The isostatic compaction mould for the ceramic long tube is characterized by comprising a hard core rod and a mould sleeve with elasticity, wherein the two ends of the mould sleeve are connected with end covers, the core rod is connected between the two end covers, the core rod is arranged in the mould sleeve, a molding mould cavity is formed between the core rod and the mould sleeve, and a hard porous supporting tube is sleeved outside the mould sleeve.
2. 2. The isostatic pressing die for the ceramic long tube as claimed in claim 1, wherein the end cover is provided with a counter bore, and the end part of the core rod is connected with the counter bore in a plug-in manner.
3. 3. The isostatic pressing die for ceramic long tubes as in claim 1, wherein the end caps and the die sleeve are made of the same material.
4. 4. The isostatic pressing die for ceramic long pipes as claimed in claim 1, wherein the core rod is made of tungsten steel or high-speed steel.
5. 5. The isostatic pressing die as defined in claim 1, wherein the end cap is in interference fit with the die sleeve.
6. 6. The isostatic pressing die for ceramic long tubes as recited in claim 1, wherein the surface of the core rod is polished.
7. 7. The isostatic pressing die for ceramic long pipes as claimed in claim 1, wherein the thickness of the porous supporting pipe is 1-3mm.
8. 8. A mould according to any one of claims 1 to 7, wherein a storage cavity is provided in an end cap, a discharge hole is provided in an end face of the end cap and is in communication with the storage cavity, the discharge hole is adapted to be connected with a lifting plug rod, one end of the plug rod plugs the discharge hole, and the other end of the plug rod extends to the outer end of the end cap.
9. 9. A ceramic long tube isostatic pressing method is characterized by adopting the ceramic long tube isostatic pressing die according to any one of claims 1-8 to process, and comprises the following steps of S1 sleeving a porous supporting tube outside a die sleeve, S2, inserting one end of a core rod and an end cover together, connecting the end cover with one end of the die sleeve, S3, filling powder into a molding die cavity, vibrating and compacting, S4, connecting the other end cover to the other end of the die sleeve, S5, loading the die sleeve into a cold isostatic pressing machine for pressing, S6, and demolding.
10. 10. The isostatic pressing method for the ceramic long tube according to claim 9, wherein in the step S2, wax liquid is coated on the outer wall of the core rod, a wax layer is formed on the outer wall of the core rod after cooling, then the core rod is connected with the end cover, and in the step S6, the core rod is demolded after the wax layer is melted by heating.

Description

Isostatic pressing mold and method for ceramic long tube Technical Field The invention relates to the technical field of ceramic product processing, in particular to an isostatic pressing die and method for a ceramic long tube. Background At present, special ceramic tubes are widely used in a plurality of fields with the advantages of excellent high temperature resistance, chemical inertness, hardness, wear resistance, electrical insulation and the like. The traditional ceramic tube processing method mainly comprises the steps of firstly utilizing an extrusion molding machine to mold, wherein the method is suitable for batch and rapid production, but has certain requirements on powder materials, when the product size is changed, a new extrusion die is needed to be replaced, equipment cost and die cost are high, secondly utilizing a cylindrical elastic die to mold a solid ceramic green body in an isostatic press, and then processing the inner and outer diameters on a machine tool, the method is long in time and is not suitable for batch production, and is only suitable for tubes with short length and overlong length, and two ends are needed to be processed or even cannot be processed, thirdly, adding an internal mandrel on the basis of the elastic isostatic die on the basis of the method II, and being used for molding a cavity with the inner diameter of a long tube. Chinese patent application number 2011205075383 discloses an isostatic compaction mould for manufacturing a ceramic tube shell, which comprises an inner mould and an outer mould, wherein a metal round tube-shaped inner mould is sleeved in a rubber tube-shaped outer mould, and the inner mould and the outer mould are assembled into a whole through rubber plugs at two ends. The mould with the structure cannot ensure the straightness of the product when processing the ceramic tube with longer length and larger length-diameter ratio. Disclosure of Invention In order to overcome the defects, the invention provides an isostatic pressing mould and method for a ceramic long tube, which can realize stable forming of the ceramic long tube and has good straightness of the formed ceramic long tube. In order to solve the technical problems, the invention adopts the following technical scheme that the isostatic pressing mould for the ceramic long tube comprises a hard core rod and a mould sleeve with elasticity, wherein the two ends of the mould sleeve are connected with end covers, the core rod is connected between the two end covers, the core rod is arranged in the mould sleeve, a forming mould cavity is formed between the core rod and the mould sleeve, and the hard porous support tube is sleeved outside the mould sleeve. In the isostatic compaction process of the ceramic long tube, the porous supporting tube with the added outer layer can increase the geometric stability of the mould at the initial stage of isostatic compaction, and the pressure is more uniformly distributed in the axial direction and the radial direction of the formed body at the initial stage of densification, so that the good straightness and uniform density of the subsequent formed body are ensured. The die can realize a special ceramic long tube with a larger length-diameter ratio value, and the formed forming body has good inner cavity straightness and smooth surface. Multiple products can be molded in batches at a time, and production efficiency and product quality are both considered. Preferably, a counter bore is arranged on the end cover, the end part of the core rod is connected with the counter bore in a plug-in way. The core rod is connected with the counter bore on the end cover in a plug-in manner, so that the assembly is convenient, and the accuracy of the position of the core rod is ensured. Preferably, the end cap and the die sleeve are made of the same material. The end cover and the die sleeve are made of the same material, the connection of the two is more reliable. Preferably, the mandrel bar is made of tungsten steel or high-speed steel. The core rod can be made of high-speed steel or tungsten steel, and for target products with the length-diameter ratio of more than 25 or the inner diameter of less than 8mm, tungsten steel is recommended, and the high-speed steel can be selected under the rest conditions, and the core rod does not shrink in the forming process, so that the diameter of the core rod is the inner diameter of the target product. Preferably, the end cap is an interference fit with the die sleeve. The interference fit connection mode is convenient and reliable in connection. Preferably, the surface of the mandrel bar is polished. The surface polishing treatment of the core rod ensures the smoothness of the inner wall of the molded product and ensures the smooth demoulding of the product. Preferably, the porous support tube has a wall thickness of 1-3mm. The wall thickness of the porous support tube is controlled within a certain range, ensuring the structur