Powdered mold manufactured based on a crucible

Abstract

The application relates to the technical field of isostatic pressing molds, in particular to a powder loading mold based on a crucible, which comprises a mold cavity forming assembly, is composed of a rubber sleeve, a core mold body and a shaping tool, the rubber sleeve is located at the outermost position, the core mold body is located at the center, the shaping tool is arranged between the rubber sleeve and the core mold body, and an annular powder filling cavity corresponding to the shape of the crucible is defined among the three; an upper sealing cover assembly is arranged above the rubber sleeve and the core mold body, the upper sealing cover is provided with feeding and distributing mechanisms, the cross-sectional area of the feeding and distributing mechanisms is gradually reduced along the material flow direction, so that the material can be uniformly dropped into the powder filling cavity; and the inflatable sealing assembly is composed of a plurality of annular sealing teeth arranged on the inner wall of the rubber sleeve, a plurality of annular tooth grooves corresponding to the annular sealing teeth arranged on the outer surface of the upper sealing cover, and a sealing mechanism capable of being inflated and tightly matched with the corresponding annular tooth groove by injecting fluid into the annular sealing teeth.

Description

Technical Field

[0001] This invention relates to the field of isostatic pressing molding technology, specifically to a powder loading mold based on crucible manufacturing. Background Technology

[0002] Cold isostatic pressing is the mainstream process for preparing high-performance ceramic crucibles, graphite crucibles, and other special crucibles. Its basic principle is to fill powder into a flexible mold, seal it, and place it in a high-pressure cylinder. Uniform ultra-high pressure (usually 100-300 MPa) is applied through a liquid medium, causing the powder to densify and form under isostatic pressure.

[0003] Refractory metal crucibles, due to their high melting point, corrosion resistance, and excellent high-temperature strength, are widely used in high-temperature industrial fields such as sapphire growth, rare earth smelting, photovoltaics, and semiconductor manufacturing. Cold isostatic pressing (CIP) is currently the mainstream process for preparing large-size, high-quality refractory metal crucible blanks. This technology involves loading powder into a flexible mold, sealing it, and placing it in a high-pressure container. A liquid medium is then used to apply uniform high pressure in all directions, compacting the powder into shape. However, existing CIP molds and processes still face numerous technical bottlenecks in practical applications, severely restricting improvements in product quality and production efficiency.

[0004] First, poor sealing reliability is a persistent problem in the industry. Traditional molds typically use rubber or polyurethane sleeves as the outer mold, with the upper end usually sealed by a flange and bolts. In ultra-high pressure liquid media environments of 180-250 MPa, the sleeve end face undergoes significant elastoplastic deformation, leading to uneven pressure distribution on the sealing surface and easily creating localized leakage channels. Once high-pressure oil seeps into the mold cavity, it severely contaminates expensive tungsten-molybdenum powder, causing the entire batch of products to be scrapped. Furthermore, the sleeve end face experiences 15%-25% permanent compression deformation during repeated compression cycles, causing the mold's sealing performance to deteriorate rapidly with increasing usage, resulting in a lifespan of only 50-100 cycles.

[0005] Secondly, controlling the uniformity of powder density is difficult. Traditional powder loading methods often involve single-point free-fall, where the powder naturally accumulates in the annular mold cavity under gravity. For fine particles with poor flowability and irregularly shaped refractory metal powders, this loading method easily leads to severe segregation and density gradients—high density near the falling point and low density further away, with the bottom powder having a higher density due to its own weight. This uneven powder loading directly results in defects such as large wall thickness deviations, poor roundness, and even localized cracking in the pressed compact after sintering.

[0006] Third, vibration densification is inefficient and prone to interference. To improve powder density, existing technologies often install vibrators around the mold. However, if multiple vibrators are arranged in the upper part of the mold cavity and operate simultaneously, the vibration waves are prone to interference within the confined annular mold cavity, forming standing waves. The presence of standing waves causes the powder to be continuously vibrated and over-compacted in some areas (antinodes), while remaining almost unvibrated and loose in other areas (nodes), thus exacerbating the density inhomogeneity. In addition, the disassembly and assembly process of traditional molds is cumbersome, usually requiring the tightening or loosening of dozens of bolts one by one, with each disassembly and assembly taking 20-40 minutes. Furthermore, the bolt preload is difficult to unify, further deteriorating the sealing effect.

[0007] Therefore, this application proposes a powder-filling mold based on crucible manufacturing. Summary of the Invention

[0008] The purpose of this invention is to provide a powder-filling mold based on crucible manufacturing to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: a powder-filling mold based on crucible manufacturing, comprising: The mold cavity forming assembly consists of a rubber sleeve, a core mold body, and a shaping tooling. The rubber sleeve is located on the outermost side, the core mold body is located in the center, and the shaping tooling is set between the rubber sleeve and the core mold body. The three components together define an annular powder filling cavity corresponding to the shape of the crucible. The upper sealing cover assembly includes an upper sealing cover that covers the rubber sleeve and the core mold body, and is provided with a feeding and distributing mechanism. The cross-sectional area of ​​the outlet of the feeding and distributing mechanism gradually decreases along the material flow direction so that the material falls evenly into the powder filling cavity. The expandable sealing assembly includes a plurality of annular sealing teeth disposed on the inner wall of the rubber sleeve, a plurality of annular grooves disposed on the outer surface of the upper sealing cover corresponding to the annular sealing teeth, and a sealing mechanism that can expand the annular sealing teeth by injecting fluid into them and press them tightly into the corresponding annular grooves.

[0010] Preferred options also include: The metal sealing self-repair structure includes a metal sealing ring surface integrally formed on the top periphery of the upper sealing cover, a metal skeleton insert embedded in the top end face of the rubber sleeve, and a plurality of concentric annular oil reservoirs formed on the lower surface of the metal sealing ring surface and / or the upper surface of the metal skeleton insert. The metal skeleton insert has an upwardly extending elastic cantilever end, the upper surface of which abuts against the lower surface of the metal sealing ring to form a metal end face seal. The cross-section of the annular oil reservoir is a trapezoidal shape with a circular bottom, and it is pre-filled with high-viscosity fluorinated grease.

[0011] Preferably, the feeding and spreading mechanism specifically includes: The lifting screw is threaded to the top center of the upper sealing cover, and the interior of the lifting screw has a central feed port that is connected to an external feed pipe along its axial direction; The diverter cone is fixedly connected to the bottom of the lifting screw and located in the inner cavity of the upper sealing cover, with its cone surface expanding outward from top to bottom; The feed through holes are evenly distributed around the downstream end of the central feed inlet, and the outlet of each feed through hole faces the upper cone surface of the flow divider cone. The tapered fabric channels are configured as multiple channels and arranged in an array along the circumference of the upper sealing cover. The inlet of each tapered fabric channel is located on the lower outer periphery of the diversion cone, and its flow cross-sectional area gradually narrows from the inlet to the outlet. The injection ring channel is constructed as an annular groove at the bottom of the upper sealing cover, and the downstream ends of each tapered material distribution channel converge to the injection ring channel, which is located directly opposite the central ring of the powder filling cavity.

[0012] Preferably, a material plug is fixedly connected to the bottom of the lifting screw and below the diversion cone, and the outer contour surface of the material plug is complementary to the inner wall surface of the injection ring channel.

[0013] Preferably, the sealing mechanism of the expandable sealing assembly specifically includes: A sealed elastic airbag is embedded in the annular cavity at the top of the rubber sleeve and located below the metal skeleton insert. The pressurization and air injection port is a long and narrow channel opened in the wall of the rubber sleeve. One end of the port is connected to the inner cavity of the sealing elastic air bladder, and the other end is connected to the inner cavity of each annular sealing tooth.

[0014] Preferred options also include: The base body has an annular positioning groove on its top surface for positioning the bottom of the rubber sleeve. The bottom of the annular positioning groove has multiple countersunk holes, and the bottom of the rubber sleeve is equipped with multiple positioning feet. The positioning feet are inserted into the corresponding countersunk holes to achieve circumferential and radial positioning of the rubber sleeve and the base body. The base body has multiple vibrators arranged in a circular array along its central circumference. These vibrators divide the annular powder filling cavity into sectors equal in number to the number of vibrators. The vibration output end of each vibrator is closely attached to the corresponding positioning foot through a metal conduction block.

[0015] Preferred options also include: A core mold vibration transmission assembly, comprising a lower cone, an elastic support ring, and a vibration transmission rod; The lower cone is fixed to the bottom center of the core mold body, and its outer surface gradually narrows from top to bottom; A tapered groove that matches the outer contour of the lower cone head is provided at the center of the base body; The elastic support ring is sleeved on the outer surface of the lower cone head and elastically abuts against the inner wall of the conical groove of the base body, providing elastic centering support for the core mold body; The vibration transmission rod is installed along the central axis of the core mold body. Its upper end is fixedly connected to the core mold body, and its lower end is threadedly connected to the connecting hole at the bottom of the conical groove of the base body or mated with the conical surface.

[0016] Preferred options also include: A hydraulic preload system, comprising multiple hydraulic rods and hydraulic nuts corresponding to each hydraulic rod; Hydraulic rods are evenly distributed along the circumference between the metal sealing ring and the metal skeleton insert. The lower end of each hydraulic rod is screwed into the corresponding threaded hole on the base body, and its upper end passes through the through hole on the outer periphery of the metal sealing ring. The hydraulic nut is fitted onto the upper end of the corresponding hydraulic tie rod that passes through the hole. The hydraulic nut has an annular hydraulic cylinder inside, with its piston end face facing the upper surface of the metal sealing ring.

[0017] Preferably, the rubber sleeve has a straight hollow structure, which consists of three sections from top to bottom: The upper sealing section is used to withstand the sealing preload and provide structural rigidity for installing the sealing assembly; The middle forming section has a uniform thickness on its outer wall. The outer wall thickness of the lower buffer section gradually increases from top to bottom.

[0018] Preferably, a demolding pressure relief valve is also installed on the outer wall of the rubber sleeve, and the demolding pressure relief valve is connected to the pressurized air injection hole and / or the internal air cavity of the sealing elastic airbag.

[0019] Compared with the prior art, the beneficial effects of the present invention are: (1) Through the three-stage uniform distribution structure of circumferential dispersion of the diversion cone, circumferential homogenization of the flow resistance of the gradually narrowing material distribution channel, and annular waterfall curtain of the injection ring channel, the single-point feeding is transformed into surface feeding that is evenly distributed along the entire circumference of the powder filling cavity. The flow cross-sectional area of ​​each gradually narrowing material distribution channel gradually narrows, making the flow resistance distribution along the circumference more uniform. The difference in powder flow velocity at the outlet of each channel is greatly reduced, and finally, the powder falls evenly into each circumferential position of the filling cavity in the form of annular waterfall curtain, thus solving the problem of uneven filling density from the source.

[0020] (2) During the assembly stage, the sealing elastic bladder is not compressed, and the annular sealing teeth are in a flexible state, allowing the upper sealing cap to be easily inserted, thus resolving the contradiction between the insertion and removal resistance and sealing pressure of traditional seals. After assembly, the compressed sealing elastic bladder causes the annular sealing teeth to expand and harden, completely fitting with the annular tooth groove to form a multi-stage tortuous labyrinth seal, significantly improving sealing reliability. The high-viscosity fluorinated grease pre-filled in the annular oil reservoir can actively flow into the micro-gap of the metal sealing surface for self-repairing and sealing under isostatic pressure, maintaining reliable sealing even after multiple thermal and pressure cycles.

[0021] (3) Multiple vibrators work sequentially and individually, with only one vibrator operating at any given time. This physically eliminates the condition that vibration waves would interfere with each other and form standing waves in the mold cavity when multiple vibration sources are excited simultaneously. Vibration energy is transmitted layer by layer from the bottom of the rubber sleeve upwards, forming a gradient compaction effect from bottom to top, ensuring that the powder at the bottom is compacted first, and then the vibration energy is transmitted upwards layer by layer, avoiding the problem of over-vibration at the top and under-vibration at the bottom. At the same time, the time-sharing operation of all vibrators makes the total power consumption significantly lower than the condition where all vibrators operate simultaneously. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the exploded structure of the present invention; Figure 3 This is a schematic diagram of the internal exploded structure of the present invention; Figure 4 This is a schematic diagram of the upper sealing cap in this invention; Figure 5 This is a schematic diagram of the rubber sleeve in this invention; Figure 6 This is a schematic diagram of the structure of the rubber sleeve and the upper sealing cap in this invention; Figure 7 For the present invention Figure 6 Enlarged structural diagram at point A; Figure 8 This is a front view structural diagram of the present invention; Figure 9 For the present invention Figure 8 Enlarged structural diagram at point B; Figure 10 This is a schematic diagram of the annular oil storage tank of the present invention.

[0023] In the diagram: 100, rubber sleeve; 101, core mold body; 102, shaping tooling; 103, lower cone head; 104, elastic support ring; 200, upper sealing cover; 201, metal sealing ring surface; 202, tapered material feeding channel; 203, flow divider cone; 204, lifting screw; 205, material feeding through hole; 206, material plug; 207, material injection ring channel; 300, annular sealing tooth; 301, annular tooth groove; 302, metal skeleton insert; 303, sealing elastic airbag; 304, pressurized air injection hole; 305, demolding pressure relief valve; 306, annular oil reservoir; 400, base body; 401, vibrator; 402, hydraulic tie rod; 403, hydraulic nut; 404, perforation; 405, positioning foot; 406, vibration transmission rod. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Example 1: Please refer to Figure 1 — Figure 10 This invention provides a technical solution: a powder-filling mold based on crucible manufacturing, used for forming crucibles in a cold isostatic pressing process. The main components of the mold include a mold cavity forming assembly, an upper sealing cover assembly and a feeding and feeding mechanism, an expandable and contractible sealing assembly, a metal sealing self-healing structure, a base body 400 and a vibration system, and a core mold vibration transmission assembly.

[0026] Please see Figure 1 , Figure 5 and Figure 8 The mold cavity forming assembly comprises a rubber sleeve 100, a core mold body 101, and a shaping fixture 102, forming the basic molding structure of the mold. The rubber sleeve 100 is a straight, hollow cylinder located at the outermost edge of the mold, and its inner wall forms the annular outer wall of the mold cavity, which is the outer contour of the crucible. The core mold body 101 is located at the center of the mold, and its outer wall forms the annular inner wall of the mold cavity, which is the inner contour of the crucible. The shaping fixture 102 is positioned between the rubber sleeve 100 and the core mold body 101 and is used to precisely shape the crucible wall thickness during isostatic pressing. The inner wall of the rubber sleeve 100, the outer wall of the core mold body 101, and the upper and lower end faces of the shaping fixture 102 together define an annular powder filling cavity that perfectly corresponds to the shape of the crucible.

[0027] The sleeve 100 is preferably made of highly elastic polyurethane or rubber material, which can elastically deform with the external medium pressure during isostatic pressing, and transmit the pressure in all directions uniformly to the powder in the powder filling cavity.

[0028] It is worth mentioning that the rubber sleeve 100 has a straight cylindrical hollow structure, which consists of three sections from top to bottom: the upper sealing section, whose outer wall thickness is greater than that of the middle forming section, has high structural rigidity and circumferential strength, and is used to withstand the sealing pre-tightening force, the axial tension of the hydraulic tie rod, and provide a structural foundation for installing the sealing components; the middle forming section, which is the main radial pressure transmission area of ​​the rubber sleeve 100, has a uniform outer wall thickness and medium rigidity to ensure that the pressure in all directions is uniformly transmitted to the powder filling cavity during isostatic pressing; and the lower buffer section, whose outer wall thickness gradually increases from top to bottom. This gradually thickened structure can buffer the axial stress concentration borne by the powder at the bottom of the mold cavity during isostatic pressing, and reduce cracking or density unevenness defects caused by excessive stress at the bottom of the compact.

[0029] Please see Figure 2 , Figure 3 and Figure 4 The upper sealing cover assembly and the feeding mechanism are as follows: the main body of the upper sealing cover assembly is the upper sealing cover 200, which is located above the rubber sleeve 100 and the core mold body 101 to seal the top of the powder filling cavity. The upper sealing cover 200 also integrates the feeding and feeding mechanisms.

[0030] The feeding and feeding mechanism includes a lifting screw 204, which is connected to the threaded hole at the center of the top of the upper sealing cover 200 via an external thread. The lifting screw 204 has a central feed port along its axial direction. The upper end of the central feed port is connected to an external feed pipe via a quick-connect coupling. At the downstream end of the central feed port, i.e. the lower end of the lifting screw 204, a plurality of feed through holes 205 are evenly provided circumferentially. The outlet direction of each feed through hole 205 faces the upper conical surface of the diverting cone 203 below.

[0031] The diversion cone 203 is fixedly connected to the bottom of the lifting screw 204 by bolts or integral machining, and is located in the inner cavity of the upper sealing cover 200. The cone surface of the diversion cone 203 expands outward from top to bottom, and is in the shape of an inverted cone or umbrella. The powder falling from the feed through hole 205 first impacts the upper cone surface of the diversion cone 203, and is evenly dispersed to various circumferential positions in the inner cavity of the upper sealing cover 200 under its guiding effect.

[0032] The interior of the upper sealing cover 200 has multiple tapered feeding channels 202 arranged in a circumferential array. In this embodiment, eight tapered feeding channels 202 are arranged at equal intervals. The inlet of each tapered feeding channel 202 is located in the outer peripheral region below the flow divider cone 203, and its flow cross-sectional area gradually narrows from the inlet to the outlet, i.e., towards the powder filling cavity. This tapered design makes the flow resistance along the circumference of the upper sealing cover 200 more uniform when the powder passes through each tapered feeding channel 202, and significantly reduces the difference in powder flow velocity at the outlet of each tapered feeding channel 202.

[0033] The downstream ends of each tapered fabric channel 202 converge to the injection ring channel 207. The injection ring channel 207 is a continuous annular groove formed on the bottom surface of the upper sealing cover 200, directly opposite the central ring of the powder filling cavity. The powder flowing out of each tapered fabric channel 202 collects in the injection ring channel 207 and then falls evenly into the powder filling cavity below in the form of an annular waterfall curtain along the entire circumference, ensuring that the powder filling cavity receives an equal amount of powder supply at every circumferential position.

[0034] See Figure 4 A material plug 206 is fixedly connected to the bottom of the lifting screw 204, located below the diverting cone 203. The outer contour surface of the material plug 206 is complementary to the inner wall surface of the injection ring channel 207, preferably with a conical surface fit or a cylindrical surface interference fit. During the powder loading process, the lifting screw 204 is in the upper position, the material plug 206 is separated from the injection ring channel 207, and the powder can flow freely through the injection ring channel 207 into the powder filling cavity. When the powder in the powder filling cavity reaches the predetermined filling amount, the operator rotates the lifting screw 204 to move it downward along the thread, causing the material plug 206 to move down synchronously into the injection ring channel 207. The injection ring channel 207 is completely sealed by the conical surface contact or interference fit, which cuts off the powder supply channel on the one hand, and prevents the external high-pressure medium from seeping into the powder filling cavity through the injection ring channel 207 in the subsequent isostatic pressing process on the other hand.

[0035] Please see Figure 6 — Figure 9 An expandable sealing assembly is used to achieve a reliable seal between the upper sealing cap 200 and the rubber sleeve 100. Its core feature is the ability to switch between flexible passage during assembly and rigid sealing in the working state. The assembly specifically includes annular sealing teeth 300, annular tooth grooves 301, a metal skeleton insert 302, a sealing elastic air bladder 303, and a pressurized air injection port 304.

[0036] The annular sealing teeth 300 consist of multiple annular sealing lips, arranged at intervals from top to bottom along the inner wall of the rubber sleeve 100. The annular sealing teeth 300 are made of a flexible elastomer material, such as rubber or polyurethane, and have a hollow, thin-walled structure, whose inner cavity can be inflated by air.

[0037] The annular grooves 301 are correspondingly formed on the outer surface of the upper sealing cover 200, and their number, position and spacing correspond one-to-one with the annular sealing teeth 300. The inner wall surface of each annular groove 301 is a contour shape adapted to the expanded annular sealing teeth 300.

[0038] The sealing elastic airbag 303 is embedded in the annular cavity at the top of the rubber sleeve 100, located below the metal skeleton insert 302. The sealing elastic airbag 303 is an elastic annular sealing airbag, and its internal volume is at its maximum when it is not subjected to axial compression in its initial state.

[0039] The pressurized air injection port 304 is a slender connecting channel opened in the wall of the rubber sleeve 100. One end of it is connected to the inner cavity of the sealing elastic airbag 303, and the other end is connected to the inner cavity of each annular sealing tooth 300, thereby connecting the sealing elastic airbag 303 and multiple annular sealing teeth 300 into a common closed air cavity.

[0040] Specifically, the working process of this expandable sealing assembly is as follows: Assembly stage: The upper sealing cap 200 is inserted into the inner hole of the rubber sleeve 100 from top to bottom. At this time, the sealing elastic airbag 303 is in a natural expansion and contraction state without axial compression, and there is no additional air pressure in the annular sealing teeth 300 connected to it, which is in a soft and deformable flexible state. Therefore, the annular sealing teeth 300 do not pose substantial resistance to the insertion of the upper sealing cap 200, and the upper sealing cap 200 can easily pass through each layer of sealing teeth to reach the predetermined installation position.

[0041] Sealing Establishment Stage: After the upper sealing cap 200 is inserted into place and the metal sealing ring surface 201 abuts against the upper surface of the metal skeleton insert 302, axial pressure continues to be applied to the upper sealing cap 200. This axial pressure is transmitted to the sealing elastic bladder 303, causing it to be axially compressed and its internal volume to decrease. The decrease in the internal volume of the sealing elastic bladder 303 allows the internal gas to be pushed through the pressurized injection port 304 into the inner cavity of each annular sealing tooth 300. Under the action of internal air pressure, each annular sealing tooth 300 expands and hardens, and its outer surface completely fits the inner wall of the corresponding annular tooth groove 301, forming a multi-stage tortuous labyrinth sealing path. The expanded annular sealing teeth 300 have sufficient structural rigidity to maintain a sealing state under isostatic pressure and ultra-high pressure environments.

[0042] See Figure 6 , Figure 7 and Figure 10The metal seal self-healing structure has multiple concentric annular oil reservoirs 306 on the lower surface of the metal seal ring 201. In this embodiment, three reservoirs are used as an example. The cross-section of each annular oil reservoir 306 is a trapezoid with a rounded bottom, that is, the bottom of the reservoir is a rounded transition, and the wall of the reservoir gradually widens from the bottom to the opening. This cross-sectional shape is beneficial for the fluorinated grease to be squeezed out of the reservoir under pressure, while the rounded bottom avoids stress concentration.

[0043] The annular oil reservoir 306 is pre-filled with high-viscosity fluorinated grease, such as perfluoropolyether grease (PFPE), before mold assembly. This fluorinated grease has the following key characteristics: incompressible, capable of shear flow under high pressure, and chemically inert, not reacting with powders or media.

[0044] Specifically, the working mechanism of this metal seal self-healing structure is as follows: Although the mating surfaces of the metal sealing annular surface 201 and the metal skeleton insert 302 have been precision-machined, at the microscopic scale, the contact surfaces still exhibit a discrete "peak-valley-peak-valley" contact state, with micron-level leakage channels penetrating the contact surfaces. When the entire mold is placed in an isostatic cylinder and pressurized to a working pressure, for example, 250 MPa, the high-pressure liquid medium surrounds the entire mold. The high-pressure medium first penetrates into the microscopic mating gap between the metal sealing annular surface 201 and the metal skeleton insert 302. Simultaneously, the high-pressure medium also acts on the exposed surface of the fluorinated grease in the annular oil reservoir 306, i.e., the side facing the mating gap. Driven by the pressure difference, the fluorinated grease is pushed and deformed and flows towards the inlet of the micron-level leakage channel. Although the micron-level channel constitutes a great flow resistance to the fluorinated grease, equivalent to a high-damping capillary, this resistance is overcome under a driving force on the order of 250 MPa. The fluorinated grease is pushed into the micro-gap channel in a shear flow manner, blocking and sealing the leakage channel. Due to the incompressible but shear-flowable properties of fluorinated grease, once it enters the micro-channels, it is not easily squeezed out in the reverse direction, thus achieving self-repairing of the seal.

[0045] It is worth mentioning that the annular oil reservoir 306 is not limited to being formed on the lower surface of the metal sealing ring 201; it can also achieve the desired effect by being formed on the upper surface of the metal skeleton insert 302.

[0046] See Figure 3 , Figure 5 and Figure 8The base 400 and vibration system are integrated. The base 400 supports and positions the rubber sleeve 100 and the core mold body 101, and also integrates a time-sharing and zone-sharing vibration system. An annular positioning groove is formed on the top surface of the base 400 for placing the bottom of the rubber sleeve 100. Multiple countersunk holes are evenly formed circumferentially at the bottom of the annular positioning groove. Multiple positioning feet 405 are correspondingly installed on the bottom of the rubber sleeve 100, and the positioning feet 405 are inserted into the corresponding countersunk holes to achieve precise circumferential and radial positioning of the rubber sleeve 100 and the base 400.

[0047] The base 400 has multiple vibrators 401 arranged in a circular array along its central circumference; in this embodiment, six vibrators are used. Each vibrator 401 is preferably a high-frequency pneumatic vibrator or a piezoelectric vibrator, with a vibration frequency range of 50–500 Hz and an amplitude range of 0.05–0.5 mm. The multiple vibrators 401 divide the annular powder filling cavity into six equal sectors along the circumference, and each vibrator 401 is responsible for applying vibration energy to the powder in its corresponding sector.

[0048] The vibration output end of each vibrator 401 is closely attached to the corresponding positioning foot 405 via a metal conduction block. The vibration energy transmission path is: vibrator 401, metal conduction block, positioning foot 405, outer wall of rubber sleeve 100 from bottom to top, and powder in the powder filling cavity.

[0049] In the powder loading and compaction process, the control system controls multiple vibrators 401 to start individually in a predetermined sequence. Specifically, one vibrator 401 starts working for a predetermined time and then stops; then the second vibrator 401 starts working for the same amount of time and then stops, and so on, until all vibrators 401 have completed one round of excitation. At any given time, only one vibrator 401 is in vibrating operation, while the others are in standby mode. This time-sharing excitation mode physically eliminates the conditions for standing waves to form due to interference between vibration waves when multiple vibration sources are simultaneously exciting the powder filling cavity. Once standing waves form, the powder will become excessively dense due to continuous vibration in the antinode region and remain loose due to almost no vibration in the node region. This periodic density deviation will be reflected in the final uniformity of the crucible wall thickness. The time-sharing excitation single vibration source mode fundamentally avoids this problem.

[0050] Furthermore, vibration energy is transmitted from the bottom of the sleeve 100 through the positioning foot 405, and the vibration wave propagates upwards along the outer wall of the sleeve 100 from the bottom. The bottom powder preferentially receives the vibration energy and is compacted first; thereafter, the vibration energy is transmitted upwards layer by layer, and the upper powder is compacted accordingly. This process creates a "gradient compaction from bottom to top" effect, which matches the characteristic that the bottom powder bears greater axial stress during isostatic pressing, further improving the uniformity of the overall density of the compact.

[0051] The 401-minute operation of each vibrator ensures that only one vibrator outputs power at any given time. The instantaneous power consumption of the system is much lower than the total power consumption of multiple vibrators operating simultaneously, which helps to reduce power capacity requirements and equipment heat dissipation burden.

[0052] See Figure 3 and Figure 8 The core mold vibration transmission assembly has a lower cone 103 fixed at the bottom center of the core mold body 101. The outer surface of the lower cone 103 gradually narrows from top to bottom, forming a cone-shaped profile. Correspondingly, a cone-shaped groove that matches the outer profile of the lower cone 103 is provided at the center of the base base 400, and the lower cone 103 is placed in the cone-shaped groove during installation.

[0053] The elastic support ring 104 is sleeved on the outer surface of the lower cone head 103, and its outer circumferential surface elastically abuts against the inner wall of the conical groove of the base body 400. The elastic support ring 104 provides elastic centering support for the mandrel body 101, allowing the mandrel body 101 to have a small amount of elastic floating freedom in the radial and axial directions, which helps to adaptively adjust the mandrel position during isostatic pressing.

[0054] The vibration transmission rod 406 is installed along the central axis of the core mold body 101. Its upper end is fixedly connected to the top of the inner hole of the core mold body 101 via a thread or flange, and its lower end is connected to the threaded hole or tapered hole in the connecting hole at the bottom of the tapered groove of the base body 400. A portion of the vibration energy generated by the vibrator 401 is transmitted to the core mold body 101 via the path of the base body 400, the vibration transmission rod 406, and the core mold body 101. In this way, the core mold body 101 and the rubber sleeve 100 can be vibrated synchronously, eliminating the vibration phase difference between the inner and outer walls of the powder filling cavity, ensuring that the powder near the inner and outer walls receives the same degree of compaction, and further improving the filling uniformity.

[0055] Among them, an annular gap is provided between the outer surface of the vibration transmission rod 406 and the inner wall of the core mold body 101. The gap is filled with silicone oil or flexible polyurethane as a vibration coupling medium to ensure that the vibration energy is uniformly transmitted from the transmission rod to the core mold body without generating hard contact noise between metals.

[0056] See Figure 1 and Figure 8 This includes multiple hydraulic tie rods 402 and hydraulic nuts 403 that mate with each hydraulic tie rod 402. In this embodiment, four hydraulic tie rods 402 are distributed at equal intervals along the circumference as an example.

[0057] The lower end of each hydraulic tie rod 402 is screwed into a corresponding threaded blind hole on the base body 400 via an external thread, achieving a rigid connection between the lower end of the tie rod and the base body 400. The upper end of each hydraulic tie rod 402 passes through a through hole 404 formed on the periphery of the metal sealing ring surface 201. The through hole 404 is a smooth hole, allowing the tie rod to pass freely. The upper end of the hydraulic tie rod 402 is machined with external threads.

[0058] The hydraulic nut 403 is sleeved on the upper end of the hydraulic tie rod 402 through the through hole 404 and locked to the upper end of the tie rod by threaded engagement. The hydraulic nut 403 is a specially designed annular hydraulic cylinder structure: it has an annular cylinder cavity and an annular piston inside, with the piston end face facing downward, i.e., the direction of the upper surface of the metal sealing ring 201, and has a reserved oil injection joint for connection with an external manual hydraulic pump.

[0059] After the mold assembly is completed and the metal sealing ring surface 201 initially contacts the metal skeleton insert 302, oil is simultaneously injected and pressurized into the annular cylinder cavity of each hydraulic nut 403 via an external manual hydraulic pump. Under hydraulic pressure, the annular piston pushes downwards, its end face pressing evenly against the upper surface of the metal sealing ring surface 201, applying a precise and controllable axial preload to the circumferential position corresponding to each hydraulic rod 402. Since each hydraulic nut 403 shares the same hydraulic source, the preload at each point is completely equal, ensuring that the metal sealing ring surface 201 and the metal skeleton insert 302 are uniformly and tightly fitted along the entire circumference. Simultaneously, the increased axial preload further compresses the sealing elastic bladder 303, increasing the expansion pressure of the annular sealing teeth 300, making the labyrinth seal more reliable.

[0060] During the demolding process, the hydraulic nuts 403 are depressurized sequentially by a manual hydraulic pump to release the axial preload.

[0061] See Figure 7 and Figure 8 A release pressure relief valve 305 is installed on the outer wall of the sleeve 100. The release pressure relief valve 305 is connected to the pressurized air injection hole 304 and / or the internal air cavity of the sealing elastic air bag 303 through a channel in the wall. The release pressure relief valve 305 is preferably a manual ball valve or a needle valve.

[0062] After isostatic pressing is completed in the demolding process, the operator first depressurizes each hydraulic nut 403 to release the preload, and then opens the demolding pressure relief valve 305. Opening the demolding pressure relief valve 305 connects the sealed elastic airbag 303 and the annular sealing teeth 300 to the outside atmosphere, allowing the high-pressure gas in the system to be rapidly discharged. After the gas is discharged, each annular sealing tooth 300 loses its air pressure support, returns to a soft, deformable flexible state, and disengages from the inner wall of the corresponding annular tooth groove 301, releasing the labyrinth seal locking state.

[0063] Afterwards, the operator can sequentially remove the upper sealing cover 200 upwards, lift the rubber sleeve 100 upwards, separate the shaping fixture 102, and finally remove the formed crucible blank from the core mold body 101.

[0064] Example 2: Please refer to Figure 1 - Figure 10 The present invention also provides a technical solution, which differs from the technical solution of Embodiment 1 as follows: a process flow for using a powder loading mold based on crucible manufacturing.

[0065] The process flow for using the powder filling mold in this embodiment is as follows: Step S1: Mold assembly.

[0066] Place the base 400 in the powder loading station, install each vibrator 401, install the core mold body 101 on the base 400 through the lower cone head 103 and the vibration transmission rod 406, install the rubber sleeve 100 in the annular positioning groove of the base 400 through the positioning foot 405, fit the shaping fixture 102 between the rubber sleeve 100 and the core mold body 101, fill each annular oil reservoir 306 with high viscosity fluorinated grease, insert the upper sealing cap 200 into the rubber sleeve 100, so that the metal sealing ring surface 201 initially contacts the metal skeleton insert 302.

[0067] Step S2: Hydraulic pretensioning.

[0068] Install hydraulic tie rods 402 and hydraulic nuts 403, inject oil and pressurize each hydraulic nut 403 by hydraulic pump, apply uniform preload force to metal sealing ring surface 201 and metal skeleton insert 302, and compress sealing elastic airbag 303 to expand and seal the annular sealing teeth 300.

[0069] Step S3: Fill with powder and vibrate to compact.

[0070] Connect the external feed pipe to the center inlet of the lifting screw 204, start the powder conveying, and the powder falls into the powder filling chamber in the form of an annular waterfall curtain through the feed through hole 205, the diversion cone 203, the gradually narrowing material distribution channel 202, and the injection ring channel 207. At the same time, control each vibrator 401 to work individually and sequentially according to the predetermined program to complete the gradient compaction of the powder. After filling is completed, turn the lifting screw 204 to make the material plug 206 block the injection ring channel 207, and remove the feed pipe.

[0071] Step S4: Isostatic pressing.

[0072] The entire mold is hoisted into the isostatic cylinder, the cylinder is sealed, and the pressure is increased to the working pressure, for example, 250 MPa. The pressure is held for a predetermined time, and the external medium pressure acts on the fluorinated grease in the annular oil reservoir 306 to complete the self-repair and sealing of the micro gaps in the metal sealing surface. During the isostatic pressing process, the rubber sleeve 100 compresses the powder inward under uniform pressure, making it dense and formed.

[0073] Step S5: Demolding.

[0074] After the isostatic pressing is completed, the pressure is released, the mold is lifted out to the demolding station, the hydraulic nut 403 is depressurized sequentially by the hydraulic pump, the hydraulic tie rod 402 and the hydraulic nut 403 are removed, the demolding pressure relief valve 305 is opened, the gas in the annular sealing tooth 300 is discharged to make it shrink and restore its flexibility, the lifting screw 204 is turned to separate the material plug 206 from the material injection ring channel 207, the upper sealing cover 200 is taken out, the rubber sleeve 100 is lifted off, the shaping fixture 102 is separated, and the formed crucible blank is taken out.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A powder-filling mold based on crucible manufacturing, characterized in that, include: The mold cavity forming assembly consists of a rubber sleeve (100), a core mold body (101), and a shaping fixture (102). The rubber sleeve (100) is located on the outermost side, the core mold body (101) is located in the center, and the shaping fixture (102) is set between the rubber sleeve (100) and the core mold body (101). The three components together define an annular powder filling cavity corresponding to the shape of the crucible. The upper sealing cover assembly includes an upper sealing cover (200) covering the rubber sleeve (100) and the core mold body (101), and is provided with a feeding and distributing mechanism. The cross-sectional area of ​​the outlet of the feeding and distributing mechanism gradually decreases along the material flow direction so that the material falls evenly into the powder filling cavity. The expandable sealing assembly includes a plurality of annular sealing teeth (300) disposed on the inner wall of the rubber sleeve (100), a plurality of annular grooves (301) disposed on the outer surface of the upper sealing cover (200) corresponding to the annular sealing teeth (300), and a sealing mechanism that can expand the annular sealing teeth (300) by injecting fluid into them and press them tightly against the corresponding annular grooves (301). The metal sealing self-repair structure includes a metal sealing ring surface (201) integrally formed on the top periphery of the upper sealing cover (200), a metal skeleton insert (302) embedded in the top end face of the rubber sleeve (100), and a plurality of concentric annular oil reservoirs (306) formed on the lower surface of the metal sealing ring surface (201) and / or the upper surface of the metal skeleton insert (302). The metal skeleton insert (302) has an upwardly extending elastic cantilever end, the upper surface of which abuts against the lower surface of the metal sealing ring (201) to form a metal end face seal. The cross-section of the annular oil reservoir (306) is a trapezoid with a circular bottom, and it is pre-filled with high-viscosity fluorinated grease. The sealing mechanism of the expandable sealing assembly specifically includes: A sealed elastic airbag (303) is embedded in the annular cavity at the top of the rubber sleeve (100) and located below the metal skeleton insert (302); The pressurized air injection port (304) is a slender channel opened in the wall of the rubber sleeve (100). One end of the port is connected to the inner cavity of the sealing elastic airbag (303), and the other end is connected to the inner cavity of each annular sealing tooth (300).

2. The powder-filling mold based on crucible manufacturing according to claim 1, characterized in that, The feeding and spreading mechanism specifically includes: The lifting screw (204) is threaded to the top center of the upper sealing cover (200), and the interior of the lifting screw (204) is provided with a central feed port connected to the external feed pipe along its axial direction; The diverting cone (203) is fixedly connected to the bottom of the lifting screw (204) and located in the inner cavity of the upper sealing cover (200), and its cone surface extends outward from top to bottom; The feed through hole (205) is evenly opened in a plurality of circumferentially along the downstream end of the central feed inlet, and the outlet of each feed through hole (205) faces the upper cone surface of the diversion cone (203); The tapered fabric channels (202) are configured as multiple channels and are arranged in an array along the circumference of the upper sealing cover (200). The inlet of each tapered fabric channel (202) is located on the lower outer periphery of the diversion cone (203), and its flow cross-sectional area gradually narrows from the inlet to the outlet. The injection ring channel (207) is constructed as an annular groove at the bottom of the upper sealing cover (200), and the downstream ends of each tapered material distribution channel (202) converge to the injection ring channel (207), which is located at the center ring of the powder filling cavity.

3. The powder-filling mold based on crucible manufacturing according to claim 2, characterized in that: At the bottom of the lifting screw (204) and below the diversion cone (203), a material plug (206) is also fixedly connected. The outer contour surface of the material plug (206) is complementary to the inner wall surface of the injection ring channel (207).

4. The powder-filling mold based on crucible manufacturing according to claim 1, characterized in that, Also includes: The base body (400) has an annular positioning groove on its top surface for positioning the bottom of the rubber sleeve (100). The bottom of the annular positioning groove has multiple countersunk holes. The bottom of the rubber sleeve (100) is equipped with multiple positioning feet (405). The positioning feet (405) are inserted into the corresponding countersunk holes to achieve circumferential and radial positioning of the rubber sleeve (100) and the base body (400). The base body (400) has multiple vibrators (401) arranged in a circular array along its center. The multiple vibrators (401) divide the annular powder filling cavity into sectors in the circumferential direction, which are equal in number to the number of vibrators (401). The vibration output end of each vibrator (401) is closely attached to the corresponding positioning foot (405) through a metal conduction block.

5. A powder-filling mold based on crucible manufacturing according to claim 4, characterized in that, Also includes: The core mold vibration transmission assembly includes a lower cone (103), an elastic support ring (104), and a vibration transmission rod (406). The lower cone (103) is fixed to the bottom center of the core mold body (101), and its outer surface gradually narrows from top to bottom; A tapered groove adapted to the outer contour of the lower cone head (103) is provided at the center of the base body (400); The elastic support ring (104) is sleeved on the outer surface of the lower cone (103) and elastically abuts against the inner wall of the conical groove of the base body (400), providing elastic centering support for the core mold body (101); The vibration transmission rod (406) is installed along the central axis of the core mold body (101). Its upper end is fixedly connected to the core mold body (101), and its lower end is threadedly connected to the connecting hole at the bottom of the conical groove of the base base (400) or mated with the conical surface.

6. A powder-filling mold based on crucible manufacturing according to claim 4, characterized in that, Also includes: A hydraulic preload system, comprising a plurality of hydraulic rods (402) and hydraulic nuts (403) corresponding to each hydraulic rod (402). Hydraulic rods (402) are evenly distributed along the circumference between the metal sealing ring surface (201) and the metal skeleton insert (302). The lower end of each hydraulic rod (402) is screwed into the corresponding threaded hole on the base body (400) by a thread, and its upper end passes through the through hole (404) opened on the periphery of the metal sealing ring surface (201). The hydraulic nut (403) is sleeved on the upper end of the corresponding hydraulic tie rod (402) that passes through the through hole (404). The hydraulic nut (403) has an annular hydraulic cylinder inside, and its piston end face faces the upper surface of the metal sealing ring (201).

7. A powder-filling mold based on crucible manufacturing according to claim 1, characterized in that, The rubber sleeve (100) has a straight hollow structure, which consists of three sections from top to bottom: The upper sealing section is used to withstand the sealing preload and provide structural rigidity for installing the sealing assembly; The middle forming section has a uniform outer wall thickness. The outer wall thickness of the lower buffer section gradually increases from top to bottom.

8. A powder-filling mold based on crucible manufacturing according to claim 1, characterized in that: A demolding pressure relief valve (305) is also installed on the outer wall of the rubber sleeve (100). The demolding pressure relief valve (305) is connected to the internal air cavity of the pressurized air injection hole (304) and / or the sealing elastic air bag (303).

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