Ceramic bell-shaped steam chamber cold isostatic pressing forming die and forming method thereof

Abstract

The application discloses a ceramic bell-shaped steam chamber cold isostatic pressing forming die, which comprises a base assembly, a carrier for supporting and transferring, an inner die assembly arranged on the base assembly and used for supporting and forming a bell-shaped steam chamber inner cavity structure, wherein a pressure cavity is arranged in the inner die assembly, a medium inlet and a medium outlet are arranged on the pressure cavity, and a medium one-way valve is arranged on the medium inlet and the medium outlet respectively, an outer die assembly arranged on the base assembly and in sealing connection with the inner die assembly and used for supporting and forming a bell-shaped steam chamber outer structure, and the outer die assembly and the inner die assembly are in sealing connection to form an isobaric stress bell-shaped steam chamber forming cavity. A forming method using the die is also disclosed. The forming die forms an isobaric stress bell-shaped steam chamber forming cavity between the inner die assembly and the outer die assembly, and cold isostatic pressing forming is carried out through a cold isostatic pressing container, so that low-cost preparation of a large bell-shaped steam chamber is realized, the deformation error is small, and the porosity and air tightness are good.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ceramic product forming, in particular to a high-purity alumina ceramic bell-shaped vapor chamber cold isostatic pressing forming die and a forming method thereof. BACKGROUND

[0002] For the semiconductor industry, the quality of semiconductor equipment directly determines the quality of the product. In the process of semiconductor preparation, etching and deposition processes are involved, which correspond to etching and deposition equipment respectively. Since high corrosive gases are involved in the etching and deposition processes, the inner cavity of the equipment and the parts directly contacted with the gas need to have corrosion resistance. In particular, the top of the equipment is the final collection place of the gas in the equipment, and the corrosion resistance of this place is particularly important. This place is called a bell-shaped vapor chamber (DOME for short). The characteristics of large-size bell-shaped vapor chamber products mainly have two points: large product size and a large dome (bell shape) existing in the product.

[0003] At present, the common method for making a bell-shaped vapor chamber DOME in China is to form a barrel-shaped material, and the barrel-shaped material is mechanically processed. As a special ceramic, the Vickers hardness of ceramic material reaches 18GPa, and the cutter can only be processed by grinding. It is very difficult to prepare the desired size and shape, and high-precision equipment and jigs are needed, and the processing time is very long, which requires more than several hundred hours.

[0004] The existing technology is difficult to realize low-cost preparation of large-size bell-shaped vapor chambers, and is prone to deformation during manufacturing, and has problems such as poor porosity and air tightness.

[0005] At present, cold isostatic pressing forming technology is a commonly used technology in ceramic forming methods. Cold isostatic pressing technology is to place the material loaded in a sealed and elastic mold in a container filled with liquid or gas, and to press the material into a solid body by applying a certain pressure to the liquid or gas, to obtain a raw-shaped blank. After the pressure is released, the mold is taken out of the container, and the blank is further shaped according to needs. Cold isostatic pressing forming technology has the characteristics of simple operation, stable quality, and uniform density of the formed body. However, the isostatic pressing process on the market can only form small-sized products, and it is difficult to form large-sized parts by cold isostatic pressing forming technology. The main reason is that large-size products, especially large-size bell-shaped vapor chamber products, have a large weight, and the forming die needs to bear the weight of the product. This requires the forming die to be internally supported. However, after setting the internal support, the static pressure received by the working surface inside the vapor chamber and the outside during the cold isostatic pressing forming process is different, which will cause the porosity and air tightness of the product working surface to be inconsistent, and the quality of the product cannot be guaranteed.

[0006] Therefore, there is an urgent need to design a low-cost, short-cycle, easy-to-process, non-deformable, and good porosity and air tightness, and good product quality consistency of the bell-shaped steam chamber forming method. SUMMARY

[0007] The purpose of the present application is to solve the problems of high cost, long cycle, easy deformation during production, poor porosity and air tightness of the existing large-size bell-shaped steam chamber, and to provide a high-purity alumina ceramic bell-shaped steam chamber cold isostatic pressing forming die and a forming method using the same, which can realize low-cost production of large-size bell-shaped steam chamber, small deformation error of the bell-shaped steam chamber during production, good porosity and air tightness, i.e. good corrosion resistance, and good overall product quality consistency.

[0008] The technical solution adopted by the present application to achieve the first invention purpose is: a ceramic bell-shaped steam chamber cold isostatic pressing forming die, comprising:

[0009] A base assembly for supporting and transporting the carrier;

[0010] An inner mold assembly arranged on the base assembly for supporting and forming the inner cavity structure of the bell-shaped steam chamber; wherein the inner mold assembly is internally provided with a pressure chamber, and the pressure chamber is provided with a medium inlet and a medium outlet, and the medium inlet and the medium outlet are respectively provided with a one-way valve;

[0011] An outer mold assembly arranged on the base assembly and sealingly connected with the inner mold assembly, which is used for supporting and forming the outer structure of the bell-shaped steam chamber;

[0012] The outer mold assembly and the inner mold assembly are sealingly connected to form an isobaric stress bell-shaped steam chamber forming cavity.

[0013] The ceramic bell-shaped steam chamber cold isobaric pressing forming die, according to the shape of the bell-shaped steam chamber, the inner die assembly and the outer die assembly are designed, so as to form an isobaric stress bell-shaped steam chamber forming cavity between the inner die assembly and the outer die assembly, in the use process, the selected alumina ceramic powder is filled in the isobaric stress bell-shaped steam chamber forming cavity, and the cold isostatic pressing container is used for cold isostatic pressing forming, so as to realize the purpose of low-cost preparation of the large bell-shaped steam chamber. Since the top of the large bell-shaped steam chamber is the final collection place of the gas in the equipment, the corrosion resistance of the top is particularly important, therefore, the forming quality of the top is the most important, in order to ensure the forming quality of the top, so that it has good porosity and air tightness, and the corrosion resistance is improved, the forming die is provided with a pressure cavity in the inner die assembly, a medium inlet and a medium outlet are arranged on the pressure cavity, and a medium one-way valve is arranged at the medium inlet and the medium outlet respectively, the medium one-way valve can fill a certain pressure medium in the pressure cavity, so as to play a supporting role in the filling process of the powder, so as to ensure that the inner die assembly will not be deformed in the filling process of the powder, so as to ensure the forming shape of the bell-shaped steam chamber to be formed, at this time, the outlet medium one-way valve is in the closed state. When cold isostatic pressing is carried out, since the pressure of the medium in the cold isostatic pressing container is much higher than the pressure of the medium in the pressure cavity, at the same time, the medium one-way valves at the inlet and the outlet are opened due to the pressure of the medium in the cold isostatic pressing container, the medium in the pressure cavity is discharged, the pressure in the pressure cavity is the same as the pressure in the cold isostatic pressing container, so that the inner die body and the outer die body outside the forming cavity are subjected to the same pressure, and the internal powder is isobarically formed, so as to ensure that the bell-shaped steam chamber after forming has the same forming quality, and the problem that the inner cavity and the outer cavity of the bell-shaped steam chamber cannot be uniformly isobarically formed is avoided. The problem that the static pressure of the working surface inside the steam chamber and the outside is different in the cold isostatic pressing forming process, which leads to the inconsistency of the porosity and air tightness of the product working surface, so that the product quality cannot be guaranteed and other problems are effectively solved. The purity of the alumina can reach more than 99.9% through the forming of the forming die, as long as the purity of the selected powder reaches a higher requirement, the purity of the bell-shaped steam chamber made can reach the set requirement, and since the inner and outer parts are isobarically formed, the deformation error of the bell-shaped steam chamber in the preparation process is small, the porosity and air tightness are good, that is, the corrosion resistance is good, the overall product quality consistency is good, and the product forming process is simple, convenient and efficient.

[0014] As preferred, the inner mold assembly comprises a metal core rod and an inner mold body covered outside the metal core rod, the inner mold body is made of rubber material, and the shape of the inner mold body is matched with the cavity of the clock-shaped steam chamber to be formed; the shape of the metal core rod is matched with the inner cavity of the inner mold body, and the metal core rod is internally provided with a cavity structure. The inner mold assembly comprises the metal core rod and the inner mold body. Since the large clock-shaped steam chamber is heavy, the metal core rod is needed to support during the forming process. In order to realize the isobaric forming of the clock-shaped steam chamber, an inner mold body is covered outside the metal core rod. The inner mold body is made of rubber material, and its shape is matched with the inner cavity of the clock-shaped steam chamber. In order to reduce the weight of the metal core mold while ensuring the support bearing, the metal core rod is internally provided with a cavity structure.

[0015] As preferred, the inlet medium one-way valve is opened outwardly and inwardly, and the outlet medium one-way valve is opened outwardly from the pressure chamber. The opening pressure of the medium one-way valve is greater than the pressure of the medium filled into the pressure chamber and less than the forming pressure in the cold static pressure container. During the assembly process, the inlet medium one-way valve is opened for medium filling due to the filled medium, and the outlet medium one-way valve is in a closed state due to insufficient pressure filled into the pressure chamber, so as to ensure that the medium in the pressure chamber is not discharged. During the forming process, since the opening pressure of the medium one-way valve is less than the forming pressure, the inlet medium one-way valve is opened under the action of the forming medium pressure, the forming medium enters the pressure chamber, and the outlet medium one-way valve is opened, so that the pressure in the pressure chamber is consistent with the forming pressure in the cold static pressure container, thereby realizing that the inner cavity and the outer cavity of the clock-shaped steam chamber are formed under the same pressure.

[0016] As preferred, the outer mold assembly comprises a mold lower cover, an outer mold body, and a mold upper cover, the outer mold body is provided with a filler port, the lower part of the outer mold body is sealingly connected with the mold lower cover, and the mold upper cover is sealingly arranged on the filler port of the outer mold body. The mold lower cover and the outer mold body are matched with the inner mold body to form an isobaric stress clock-shaped steam chamber forming cavity, and the filler port is arranged to facilitate filling the selected powder into the forming cavity.

[0017] As preferred, the outer mold body is made of rubber material, the shape of the inner cavity of the outer mold body is matched with the shape of the arc-shaped chamber top outer wall of the clock-shaped steam chamber to be formed, and the lower part of the outer mold body is provided with an upper mold buckling structure. The outer mold body is made of rubber material, which can ensure isobaric stress and quickly form the clock-shaped steam chamber. The upper mold buckling structure arranged on the lower part of the outer mold body is arranged to facilitate the sealing structure formed by buckling with the mold lower cover.

[0018] As preferred, the lower mold cover is a ring-shaped cover body, a center of the lower mold cover is provided with an inner mold assembly sealing sleeve joint hole, an upper ring surface of the lower mold cover is consistent with a lower ring surface of a ring-shaped chamber of a to-be-formed clock-shaped chamber, an outer ring wall of the lower mold cover is integrally provided upward with a lower mold buckling structure, and a lower ring surface of the lower mold cover is integrally provided downward with a sleeve joint boss. The lower mold cover is provided as a ring-shaped cover body to facilitate sealing cooperation with the inner mold assembly and the outer mold body, so as to form an isobaric stress clock-shaped chamber forming cavity. Such a structure is convenient to assemble and fast to operate.

[0019] As preferred, the base assembly comprises a base and a support frame, the base is arranged on the support frame, an outer periphery of a bottom surface of the base is integrally provided upward with a limiting body, a plurality of core rod connecting holes and inner mold connecting holes are arranged on the base, a drain hole is arranged at the center of the base, and ring grooves corresponding to inlets and outlets of the inner mold assembly are arranged on the base. The base assembly is provided with the base to support the isobaric stress clock-shaped chamber forming cavity formed by the inner mold assembly and the outer mold assembly, so as to support the forming process and the formed clock-shaped chamber, and the support frame is arranged to facilitate carrying, so that the forming mold can be put into a cold isostatic pressing forming container for cold isostatic pressing forming.

[0020] The technical scheme adopted by the present application to achieve the second application purpose is a method for forming by using a ceramic clock-shaped chamber cold isostatic pressing forming mold, comprising the following steps:

[0021] Step 1: selecting an alumina ceramic powder, selecting an alumina ceramic powder with a mass percentage purity of ≥99.9% and a particle size D50 of 0.5 μm and a BET specific surface area of 7.5 m2 / g;

[0022] Step 2: performing primary vibration on the selected alumina ceramic powder;

[0023] Step 3: completing assembly of the ceramic clock-shaped chamber cold isostatic pressing forming mold, and filling a certain pressure medium in a pressure cavity of the inner mold body, so that an isobaric stress clock-shaped chamber forming cavity is formed among the inner mold body, the lower mold cover and the outer mold body after assembly;

[0024] Step 4: loading the alumina ceramic powder into the isobaric stress clock-shaped chamber forming cavity through a filling port, and performing secondary vibration, and after the vibration is completed, sealing the mold upper cover on the outer mold body, so that the isobaric stress clock-shaped chamber forming cavity is in a completely sealed state;

[0025] Step 5: putting the ceramic clock-shaped chamber cold isostatic pressing forming mold filled with the alumina ceramic powder in step 4 into a cold isostatic pressing container, pressurizing the ceramic clock-shaped chamber cold isostatic pressing forming mold, and keeping the pressure;

[0026] Step 6: take out the ceramic bell-shaped steam chamber cold isostatic pressing forming mold, and demold the ceramic bell-shaped steam chamber.

[0027] The method for forming the ceramic bell-shaped steam chamber cold isostatic pressing forming mold uses a cold isostatic pressing container to pressurize the ceramic bell-shaped steam chamber cold isostatic pressing forming mold, and keeps the pressure, so that the pressure received by each position of the ceramic bell-shaped steam chamber cold isostatic pressing forming mold is uniform, and the shape of the formed ceramic bell-shaped steam chamber is regular, without edge collapse or cracking. Moreover, through the method, ceramic bell-shaped steam chambers of various shapes can be formed, and the cost of mechanical processing is saved. The inner mold body and the outer mold body play a good shaping role, which can not only prevent the bell-shaped steam chamber from deforming greatly, but also can fill the pressure medium in the pressure cavity in advance, so as to achieve good shaping while facilitating the flow of high-pressure medium in the cold isostatic pressing forming process, so that the pressure received by each position of the ceramic bell-shaped steam chamber cold isostatic pressing forming mold is uniform. The alumina ceramic powder filled into the ceramic bell-shaped steam chamber cold isostatic pressing forming mold is subjected to secondary vibration and supplementing, so as to further vibrate and compact the powder, reduce the gap between the powder, and further improve the porosity and air tightness of the formed ceramic dome. The high-purity alumina ceramic dome prepared by using the above preparation method has a deformation error of each surface of less than 3 mm, and the formed bell-shaped steam chamber does not need subsequent processing. The purity of the obtained ceramic bell-shaped steam chamber alumina can reach more than 99.9%, the corrosion resistance is good, and the product forming process is simple, convenient and efficient.

[0028] As preferred, the medium filled in the pressure cavity in step 3 is the same as the medium in the cold isostatic pressing container, and the pressure is less than the pressure of the medium in the cold isostatic pressing container. The medium in the pressure cavity uses the same medium as in the cold isostatic pressing container, which is designed to make the forming mold in the same medium during the cold isostatic pressing forming process, bear the same forming pressure, and realize isostatic pressure forming, so as to ensure the quality of the formed product and improve the corrosion resistance.

[0029] As preferred, the pressure applied to the ceramic bell-shaped steam chamber cold isostatic pressing forming mold in step 5 is 160-200 MPa, and the pressure keeping time is 20-30 min; during the pressure applying process, the medium in the cold isostatic pressing container enters the pressure cavity through the import medium one-way valve, and the medium in the pressure cavity is discharged to the cold isostatic pressing container through the export medium one-way valve, and is further pressurized to 160-200 MPa to form an integrated pressure medium. The high-pressure medium is transported to the pressure cavity through the import medium one-way valve, so that the original medium in the pressure cavity is discharged to the cold isostatic pressing container, and is pressurized to form an isostatic medium with the medium in the cold isostatic pressing container, so as to apply forming pressure to the forming mold and ensure the quality of the formed product.

[0030] The beneficial effects of the present application are: the ceramic bell-shaped steam chamber cold isostatic pressing forming die, according to the shape of the bell-shaped steam chamber, the inner die assembly and the outer die assembly are designed, so that a bell-shaped steam chamber forming cavity is formed between the inner die assembly and the outer die assembly, and cold isostatic pressing is carried out through the cold isostatic pressing container, so that the purpose of low-cost preparation of large bell-shaped steam chambers is realized. The deformation error of the bell-shaped steam chamber during preparation is small, the porosity and air tightness are good, that is, the corrosion resistance is good, the overall product quality consistency is good, and the product forming process is simple, convenient and efficient. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a structure schematic diagram of a bell-shaped steam chamber to be formed according to the present application;

[0032] Figure 2 is a structure schematic diagram of a ceramic bell-shaped steam chamber cold isostatic pressing forming die according to the present application;

[0033] Figure 3 is an application structure schematic diagram of forming by using the ceramic bell-shaped steam chamber cold isostatic pressing forming die according to the present application;

[0034] Figure 4 is a structure schematic diagram of a ceramic bell-shaped steam chamber cold isostatic pressing forming die in Example 2;

[0035] In the figure: 1, bell-shaped steam chamber to be formed, 11, arc-shaped chamber top, 12, annular steam chamber, 13, steam chamber cavity;

[0036] 2, base assembly, 21, base, 22, support frame, 23, limiting body, 24, connecting hole, 25, drainage hole, 26, ring groove, 27, inner die connecting hole;

[0037] 3, inner die assembly, 31, metal core rod, 32, inner die main body, 33, cavity structure, 34, pressure cavity, 35, inlet, 36, outlet, 37, medium one-way valve;

[0038] 4, outer die assembly, 41, die lower cover, 42, outer die main body, 43, die upper cover, 44, lower die buckling structure, 45, upper die buckling structure, 46, sleeve connection boss, 47, filler port, 48, inner die assembly sealing sleeve connection hole;

[0039] 5, bell-shaped steam chamber forming cavity, 6, cold isostatic pressing container, 7, aluminum oxide ceramic powder, 8, medium. DETAILED DESCRIPTION

[0040] The various aspects of the present application will be described in detail below with specific examples and in conjunction with the accompanying drawings.

[0041] Example 1:

[0042] In Figure 1In the embodiment shown, the bell-shaped steam chamber 1 to be formed includes an arc-shaped chamber top 11 and an annular steam chamber 12. The annular steam chamber is provided with a steam chamber cavity 13 with an arc-shaped cavity top. Specifically, in this embodiment, the maximum outer diameter of the arc-shaped chamber top is 1160 mm, the annular outer diameter of the annular steam chamber is 730 mm, and the wall thickness of the bell-shaped steam chamber is 95 mm.

[0043] like Figure 2 As shown, a ceramic bell-shaped vapor chamber cold pressing molding die includes a base assembly 2, an inner mold assembly 3, and an outer mold assembly 4. The base assembly 2 is provided to support the mold, molding powder, molded product, and serve as a carrier for transfer.

[0044] The inner mold assembly 3 is mounted on the base assembly 2 and is used to support and form the bell-shaped chamber cavity structure of the steam chamber; wherein, the inner mold assembly 3 is provided with a pressure chamber 34, and the pressure chamber 34 is provided with a medium inlet 35 and a medium outlet 36, and a medium check valve 37 is provided on the medium inlet 35 and the medium outlet 36 respectively.

[0045] The outer mold assembly 4 is mounted on the base assembly 2 and is sealed to the inner mold assembly 3. It is used to support and form the external structure of the bell-shaped steam chamber. The outer mold assembly 4 and the inner mold assembly 3 are sealed to form the bell-shaped steam chamber forming cavity 5 under equal pressure.

[0046] The base assembly 2 includes a base 21 and a support frame 22. The support frame 22 is fixed to the lower part of the base 21 and is used to support and transport the molding mold. Therefore, the support frame 22 is set as a frame structure to facilitate forklift transport.

[0047] The base 21 is made of a hard material, specifically metal, and mainly serves to support the load. A limiting body 23 is provided on the outer periphery of the seat surface of the base 21. In this embodiment, the limiting body 23 is a limiting ring integrally formed upward with the seat surface of the base. Several core rod connecting holes 24 and inner mold connecting holes 27 are evenly distributed on the base. The core rod connecting holes 24 are used to connect the base to the metal core rod, and the inner mold connecting holes 27 are used to connect the base to the inner mold body. A drain hole 25 is provided in the center of the base 21. The drain hole is used to discharge the medium in the cavity structure of the metal core rod during the cold pressing process.

[0048] The outer mold assembly 4 comprises a mold lower cover 41, an outer mold body 42 and a mold upper cover 43. The mold lower cover 41 is sealingly connected with the outer mold body 42. The inner cavity of the outer mold body 42 has the same shape as the outer wall of the arc-shaped chamber top of the to-be-formed clock-shaped steam chamber 1. The upper cover surface of the mold lower cover 41 is consistent with the annular surface of the annular chamber of the to-be-formed clock-shaped steam chamber. The mold lower cover 41 is an annular cover body. The center of the mold lower cover 41 is provided with a mold lower cover sealing sleeve joint hole 48. The upper annular surface of the mold lower cover 41 is consistent with the lower annular surface of the annular chamber of the to-be-formed clock-shaped steam chamber. The outer annular wall of the mold lower cover 41 is integrally provided with a lower mold buckling structure 44 upward. The lower annular surface of the mold lower cover 41 is integrally provided with a sleeve joint boss 46 downward. The lower mold buckling structure 44 of the mold lower cover 41 is sealingly buckled with the outer mold body 42. The lower mold buckling structure is a clamping groove. The upper mold buckling structure 45 is correspondingly arranged at the lower part of the outer mold body 42. The upper mold buckling structure is a clamping ring. The sleeve joint boss 46 is arranged below the mold lower cover 41. The sleeve joint boss 46 is arranged in cooperation with the limiting body 23 on the base. The top center of the outer mold body 42 is provided with a filler port 47. The filler port 47 is sealingly covered with the mold upper cover 43.

[0049] The inner mold assembly 3 comprises a metal core rod 31 and an inner mold body 32. The inner mold body 32 and the outer mold body 42 are both made of rubber material. The outer shape of the inner mold body 32 is arranged in cooperation with the steam chamber body 13 of the arc-shaped cavity top. The metal core rod 31 is determined according to the product shape and the inner mold body 32. It is necessary to ensure uniform stress in the CIP process. In the embodiment, the metal core rod 31 has a hollow structure 33 inside. The hollow structure can reduce the cost and reduce the weight of the core rod. On the premise of ensuring the bearing strength requirement, the wall thickness of the metal core rod can be as thin as possible.

[0050] The inner mold body 32 is provided with a pressure cavity 34, and the inner mold body is provided with an inlet 35 and an outlet 36 which are communicated with the pressure cavity, and the inlet and the outlet are respectively provided with a medium one-way valve 37, the medium one-way valve at the inlet can be opened in an outward-to-inward one-way manner, and the medium one-way valve at the outlet can be opened in a pressure cavity-to-outward one-way manner. The opening pressure of the medium one-way valve 37 is greater than the pressure of the medium filled into the pressure cavity and is less than the molding pressure in the cold isostatic container. The opening pressure of the medium one-way valve 37 is greater than the pressure of the medium filled into the pressure cavity, and during the assembly process, the inlet medium one-way valve 37 is opened for medium filling due to the filling medium, but the outlet medium one-way valve is in a closed state due to the insufficient pressure filled into the pressure cavity, so as to ensure that the medium in the pressure cavity is not discharged. By providing two medium one-way valves on the inner mold body, the inner mold body can be filled with liquid or gas medium 8 before the mold is filled with material, so that the pressure cavity is filled with the medium 8, so as to realize the bearing of the inner mold body. The structure design makes the inner mold body, the outer mold body, the mold upper cover and the mold lower cover have the same material, and during the cold isostatic molding process, all surfaces of the product to be molded have the same pressure, so that the deformation of the molded product is small, the porosity and the air tightness are more uniform, and better quality requirements can be achieved. At the same time, since the inner cavity of the bell-shaped chamber is used for collecting high-corrosive gas during etching and deposition in the use process, the setting of the same material mold ensures the corrosion resistance of the inner cavity. During the molding process, since the opening pressure of the medium one-way valve is less than the molding pressure, the medium one-way valve at the inlet is opened under the action of the molding medium pressure, the molding medium enters the pressure cavity, and the medium one-way valve at the outlet is opened, so that the pressure in the pressure cavity is consistent with the molding pressure in the cold isostatic container, so as to realize that the inner cavity and the outer cavity of the bell-shaped chamber are molded under the same pressure.

[0051] Corresponding to the medium one-way valve on the inner mold body, a ring groove 26 is formed on the seat surface of the base 21, so that the medium can enter the medium one-way valve through the base during the cold isostatic molding process, so as to enter the pressure cavity, so as to realize that the inner mold body and the outer mold body are in the same cold isostatic condition, so as to realize that the bell-shaped chamber to be molded can be molded under the same condition, so as to ensure the manufacturing quality of the bell-shaped chamber.

[0052] The base assembly, the inner mold assembly and the outer mold assembly need to be specially considered in terms of size matching, because if the matching between them is not good, leakage is easy to occur during the CIP process, which can cause the medium to enter the mold and contaminate the powder, directly leading to scrap.

[0053] As Figure 3As shown, the medium in the cold isostatic pressing in the embodiment adopts liquid, for example, water. The following takes water as the medium of cold isostatic pressing, and the steps of the ceramic bell-shaped chamber cold isostatic pressing mold are as follows.

[0054] A ceramic bell-shaped chamber forming method, comprising the following steps:

[0055] Step 1: Selecting an alumina ceramic powder 7; the selected alumina ceramic powder has a particle size D50 of 0.5 μm and a BET specific surface area of 7.5 m2 / g.

[0056] Step 2: Selecting an ultrasonic vibration device to perform primary vibration on the selected alumina ceramic powder to reduce the inter-particle voids;

[0057] Step 3: Assembling the ceramic bell-shaped chamber cold isostatic pressing mold, and filling a certain pressure gas or liquid into the pressure cavity 34 inside the inner mold body; the pressure gas or liquid in the pressure cavity 34 is the same as the medium 8 in the cold isostatic pressing container 6, and the pressure is less than the pressure of the medium in the cold isostatic pressing container 6; the pressure of the medium filled into the pressure cavity 34 can be air or water, etc.; in the embodiment, the liquid water is filled into the pressure cavity, and the pressure is less than 100 MPa, and in the embodiment, the pressure is 80 MPa. During the assembly process, the airtightness of the whole assembly is ensured, so that the inner mold body, the mold lower cover, and the outer mold body form an isostatic pressure bell-shaped chamber forming cavity 5;

[0058] Step 4: Filling the alumina ceramic powder into the isostatic pressure bell-shaped chamber forming cavity 5, and performing secondary vibration through the ultrasonic vibration device; after the vibration is completed, the mold upper cover 43 is sealed on the outer mold body 42, so that the isostatic pressure bell-shaped chamber forming cavity 5 is in a completely sealed state;

[0059] Step 5: Put the ceramic DOME cold isostatic pressing forming mold filled with alumina ceramic powder in step 4 into the cold isostatic pressing container 6, and pressurize the ceramic DOME cold isostatic pressing forming mold with the liquid cold isostatic pressing cylinder, and keep the pressure; the cold isostatic pressing cylinder pressurizes the ceramic DOME cold isostatic pressing forming mold to 160-200 MPa, and keeps the pressure for 20-30 min. In this embodiment, the pressure is 160 MPa, and the pressure keeping time is 20 min. The alumina ceramic powder with appropriate particle size, and the appropriate size of the static pressure and the pressure keeping time are needed to ensure the quality of the ceramic guide rail. During the pressurization process, because the pressure outside the inner mold body is greater than the pressure in the pressure chamber, the imported medium one-way valve is opened, the external liquid enters the inside of the pressure chamber and discharges the internal liquid through the outlet medium one-way valve, so that the pressure chamber and the liquid pressure inside the cold isostatic pressing container are in the same pressure state. The formed DOME is under the same pressure on all forming surfaces, and the forming effect is good, and the air tightness and porosity are better;

[0060] Step 6: Take out the ceramic DOME cold isostatic pressing forming mold, and take out the ceramic DOME.

[0061] The alumina ceramic powder is vibrated before being filled into the ceramic DOME cold isostatic pressing forming mold, which can reduce the gap between the powders and improve the porosity and air tightness of the formed ceramic DOME.

[0062] The ceramic DOME cold isostatic pressing forming mold is pressurized and kept by the cold isostatic pressing cylinder, so that the pressure received by each position of the ceramic DOME cold isostatic pressing forming mold is uniform, and the formed ceramic DOME has a regular shape without edge collapse and cracking. The ceramic DOME cold isostatic pressing forming mold can form ceramic DOMEs of various shapes, which saves the cost of mechanical processing. The inner mold body and the outer mold body play a good shaping role, which can prevent the DOME from deforming too much, and can fill the pressure medium in the pressure chamber in advance to achieve good shaping and facilitate the flow of high-pressure liquid during cold isostatic pressing. The pressure received by each position of the ceramic DOME cold isostatic pressing forming mold is uniform. The alumina ceramic powder filled in the ceramic DOME cold isostatic pressing forming mold is vibrated to further compact the powder and reduce the gap between the powders, which is beneficial to further improve the porosity and air tightness of the formed ceramic DOME.

[0063] The high-purity alumina ceramic DOME prepared by the above preparation process has a deformation error of each surface below 3 mm. The obtained ceramic guide rail has an alumina purity of above 99.9%, good corrosion resistance, simple, convenient and efficient product forming process.

[0064] Example 2:

[0065] InFigure 4 In the embodiment shown, the to-be-formed clock-shaped steam chamber 1 includes an arc-shaped chamber top 11 and a ring-shaped steam chamber 12, and the ring-shaped steam chamber 12 is internally provided with a steam chamber cavity 13 with an arc-shaped cavity top. In this embodiment, the maximum outer diameter of the arc-shaped chamber top is 4800 mm, the outer diameter of the ring-shaped steam chamber is 800 mm, and the wall thickness of the clock-shaped steam chamber is 40 mm.

[0066] In this embodiment, the lower mold clamping structure 44 is provided on the lower mold cover 41 and is sealed and clamped with the outer mold body 42. The lower mold clamping structure is a clamping table. Correspondingly, the upper mold clamping structure 45 is provided at the lower part of the outer mold body 42. The upper mold clamping structure is a clamping ring.

[0067] In this embodiment, a forming method of a ceramic clock-shaped steam chamber includes the following steps:

[0068] Step 1: Selecting an alumina ceramic powder with a mass percentage purity of ≥99.9% and a particle size D50 of 0.5 μm and a BET specific surface area of 7.5 m2 / g.

[0069] Step 2: Selecting the corresponding powder, then placing the powder on the top layer of the vibrating screen with a forklift, vibrating for 15 minutes, opening the top powder leakage switch, vibrating for 20 minutes for 1 / 3, vibrating for 20 minutes for 2 / 3, and vibrating for 20 minutes for 3 / 3. Each time, the vibrating screen outlet is connected to the ceramic clock-shaped steam chamber cold isostatic pressing forming mold through a pipeline. During the powder loading process, the ceramic clock-shaped steam chamber cold isostatic pressing forming mold can be further vibrated to reduce the gap between the powders, which is beneficial to further improve the porosity and air tightness of the formed ceramic DOME. In this embodiment, a mechanical vibration device is used to vibrate the powder in the vibrating screen, which also meets the requirement of reducing the gap between the powders.

[0070] Step 3: The ceramic clock-shaped steam chamber cold isostatic pressing forming mold includes a metal base 21, a metal core rod 31, an inner mold body 32, a rubber mold lower cover 41, a rubber mold upper cover 43, and a rubber outer mold body 42. The metal core rod is fixed on the metal base through a screw rod. The rubber mold lower cover is placed above the metal base by passing through the metal core rod. The rubber mold outer cover is then put on. The joint is sealed with adhesive tape. The ceramic powder is filled, the rubber outer mold body is covered, and the joint is sealed with adhesive tape. The entire ceramic clock-shaped steam chamber cold isostatic pressing forming mold is placed in a stainless steel cage.

[0071] The assembly of the ceramic bell-shaped steam chamber cold isostatic pressing forming die is completed, the metal core rod is fixed on the metal base through the screw rod, the inner die body cover is arranged outside the metal core rod and connected with the metal base, and certain pressure gas is filled in the pressure cavity of the inner die body. The pressure gas in the pressure cavity is the same as the medium gas in the cold isostatic pressing container 6, and the pressure is less than the pressure of the medium gas in the cold isostatic pressing container 6. The medium pressure filled in the pressure cavity can only be able to support the forming effect of the cooperation of the inner die body and the metal core rod; it can be air or water; in the embodiment, the pressure air is filled in the pressure cavity, and the pressure is less than 100 MPa. In the embodiment, the pressure is set to 90 MPa. The rubber die lower cover is arranged outside the inner die body, is placed above the metal base, and then the rubber outer die body is sleeved, the joint is sealed by winding with adhesive tape, the ceramic powder is filled, the rubber die upper cover is covered, and the joint is sealed by winding with adhesive tape. During the assembly process, the airtightness of the whole assembly is ensured, so that the inner die body 32, the die lower cover 41 and the outer die body 42 form an isobaric stress bell-shaped steam chamber forming cavity 5; the whole ceramic bell-shaped steam chamber cold isostatic pressing forming die is placed in a stainless steel cage.

[0072] Step 4: The alumina ceramic powder is filled into the isobaric stress bell-shaped steam chamber forming cavity 5, and is vibrated again by the vibration device. After the vibration is completed, the die upper cover 43 is arranged on the outer die body 42 to seal the isobaric stress bell-shaped steam chamber forming cavity 5 in a completely sealed state.

[0073] Step 5: The ceramic bell-shaped steam chamber cold isostatic pressing forming die filled with alumina ceramic powder in step 4 is placed in the cold isostatic pressing container 6, and the ceramic bell-shaped steam chamber cold isostatic pressing forming die is pressed by the gas cold isostatic pressing cylinder and is kept at pressure. The cold isostatic pressing cylinder is pressed to 160-200 MPa, and is kept at pressure for 20-30 min. In the embodiment, the pressure is 200 MPa, and the pressure is kept for 30 min. The alumina ceramic powder with appropriate particle size, and the appropriate size of the static pressure and the pressure holding time are beneficial to ensure the quality of the ceramic guide rail. During the pressing process, because the pressure outside the inner die body is greater than the pressure of the pressure cavity, the imported medium one-way valve is opened, the high-pressure gas outside enters the pressure cavity and discharges the gas inside through the outlet medium one-way valve, so that the pressure cavity and the gas pressure inside the cold isostatic pressing container are in the same pressure state. The formed bell-shaped steam chamber is under the same pressure on all forming surfaces, the forming effect is good, and the air tightness and porosity are better;

[0074] Step 6: The ceramic bell-shaped steam chamber cold isostatic pressing forming die is taken out, and the ceramic bell-shaped steam chamber is taken out.

[0075] The ceramic dome prepared by the forming method of the ceramic dome has regular shape, no edge collapse, no cracking, no pollution and no pores on the surface, and the deformation of each aspect is less than 3mm, without mechanical processing, meeting the use requirements.

[0076] The above-mentioned embodiments are only the preferred schemes of the present application, and do not limit the present application in any form, and other variants and modifications are also possible without exceeding the technical schemes recited in the claims.

Claims

1. A ceramic bell-shaped steam chest cold isostatic pressing forming mold characterized by The utility model relates to a kind of cold isomeric pressure container forming device, including: Base assembly (2) for supporting and transporting carrier; Inner mold assembly (3) is arranged on base assembly (2), for supporting and forming the assembly of bell-shaped steam chamber inner cavity structure;Wherein, the inside of the inner mold assembly (3) is provided with pressure chamber (34), the medium inlet (35) and medium outlet (36) are provided on the pressure chamber (34), and the medium one-way valve (37) is respectively provided on medium inlet (35) and medium outlet (36);The pressure of medium one-way valve opening is greater than the medium pressure filled to the inside of pressure chamber and less than the forming pressure in the inside of cold isomeric pressure container;The medium in the inside of pressure chamber uses the same medium in the inside of cold isomeric pressure container;During forming, medium enters into the inside of pressure chamber by inlet medium one-way valve, and the medium in the inside of pressure chamber is discharged to the inside of cold isomeric pressure container by outlet medium one-way valve and is further pressurized, forms integrated pressure medium, forms isobaric medium; Outer mold assembly (4) is arranged on base assembly (2) and is sealedly connected with inner mold assembly (3), and it is used for supporting and forming the bell-shaped steam chamber external structure; The inner mold assembly (3) includes metal core rod (31) and inner mold body (32) covered in the outside of metal core rod (31), and the inner mold body (32) is rubber material;The outer mold assembly (4) includes mold lower cover (41), outer mold body (42) and mold upper cover (43), and the outer mold body (42) is rubber material; The outer mold assembly (4) and inner mold assembly (3) are sealedly connected and form isobaric stress bell-shaped steam chamber forming cavity (5).

2. A ceramic bell-shaped steam chamber cold isostatic pressing forming die according to claim 1, characterized in that: The shape of the inner mold body (32) is cooperatively arranged with the steam chamber cavity of the bell-shaped steam chamber to be formed, the shape of the metal core rod (31) is cooperatively arranged with the inner cavity of the inner mold body (32), and the inside of the metal core rod (31) is provided with cavity structure (33).

3. A ceramic bell-shaped die cavity for cold isostatic pressing according to claim 2, characterized in that: The inlet medium one-way valve is opened outwardly and inwardly, and the outlet medium one-way valve is opened outwardly from the pressure chamber.

4. The ceramic bell-shaped steam chamber cold isostatic pressing forming die according to claim 1, characterized in that: The outer mold body (42) is provided with a filler port (47), the lower part of the outer mold body (42) is sealedly connected with the mold lower cover (41), and the mold upper cover (43) is sealedly covered on the filler port (47) of the outer mold body.

5. A ceramic bell-shaped die cavity for cold isostatic pressing according to claim 4, characterized in that: The inner cavity shape of the outer mold body (42) is cooperatively arranged with the arc-shaped chamber top outer wall shape of the bell-shaped steam chamber to be formed, and the lower part of the outer mold body (42) is provided with an upper mold buckling structure (45).

6. A ceramic bell-shaped die cavity for cold isostatic pressing according to claim 4, wherein: The mold lower cover (41) is a ring-shaped cover body, the center of the mold lower cover (41) is provided with an inner mold assembly sealing sleeve joint hole (48), the upper ring surface of the mold lower cover (41) is consistent with the lower ring surface of the annular steam chamber to be formed, the outer ring wall of the mold lower cover (41) is integrally provided with a lower mold buckling structure (44) upward, and the lower ring surface of the mold lower cover (41) is integrally provided with a sleeve joint boss (46) downward.

7. A ceramic bell-shaped die for cold isostatic pressing according to any one of claims 1 to 6, characterized in that: The base assembly (2) comprises a base (21) and a support frame (22), the base (21) is arranged on the support frame (22), the outer periphery of the bottom surface of the base (21) is integrally upwardly provided with a limiting body (23), a plurality of core rod connecting holes (24) and inner mold connecting holes (27) are arranged on the base (21), a drainage hole (25) is arranged at the center of the base (21), and ring grooves (26) are arranged on the base (21) corresponding to the inlets and outlets of the inner mold assembly.

8. A method of molding using the ceramic bell-shaped steam chamber cold isostatic pressing molding mold according to any one of claims 1 to 7, characterized by The method comprises the following steps: Step 1: selecting an alumina ceramic powder; An alumina ceramic powder with a mass percentage purity of ≥99.9% and a particle size D50 of 0.5 μm and a BET specific surface area of 7.5 m2 / g is selected; Step 2: primary vibration of the selected alumina ceramic powder; Step 3: assembly of the ceramic bell-shaped steam chamber cold isostatic pressing forming die is completed, and a certain pressure medium is filled in the pressure cavity (34) of the inner mold body (32), and an isobaric stress bell-shaped steam chamber forming cavity (5) is formed between the inner mold body (32), the lower die cover (41) and the outer mold body (42) after assembly; Step 4: the alumina ceramic powder is filled into the isobaric stress bell-shaped steam chamber forming cavity (5) through the filling port (47), and secondary vibration is performed, and after the vibration is completed, the upper die cover (43) is arranged on the outer mold body (42) to seal the isobaric stress bell-shaped steam chamber forming cavity (5) in a completely sealed state; Step 5: the ceramic bell-shaped steam chamber cold isostatic pressing forming die filled with the alumina ceramic powder in step 4 is placed in the cold isostatic pressing container (6), the ceramic bell-shaped steam chamber cold isostatic pressing forming die is pressurized, and the pressure is maintained; during the pressurization process, the medium in the cold isostatic pressing container (6) enters the pressure cavity (34) through the inlet medium one-way valve, the medium in the pressure cavity (34) is discharged to the inside of the cold isostatic pressing container (6) through the outlet medium one-way valve, and the pressure is further increased to form an integrated pressure medium; Step 6: the ceramic bell-shaped steam chamber cold isostatic pressing forming die is taken out, and the ceramic bell-shaped steam chamber is taken out after demolding.

9. The method of claim 8, wherein the forming is performed using a ceramic bell-shaped die. The medium filled in the pressure cavity (34) in step 3 is the same as the medium in the cold isostatic pressing container, and the pressure is less than the pressure of the medium in the cold isostatic pressing container (6).

10. The method of claim 8, wherein the forming is performed using a ceramic bell-shaped die. In step 5, the pressure of the ceramic bell-shaped steam chamber cold isostatic pressing forming die is 160-200 MPa, and the pressure maintaining time is 20-30 min; the medium in the pressure cavity (34) is discharged to the inside of the cold isostatic pressing container (6) through the outlet medium one-way valve, and the pressure is further increased to 160-200 MPa to form an integrated pressure medium.

Images