3D printing multi-channel ceramic sagger and using method thereof

Abstract

The invention discloses a 3D printing multi-channel ceramic sagger and a using method thereof, and relates to the technical field of ceramic additive manufacturing and post-processing. The ceramic sagger comprises a sagger body with an open top, and is characterized in that a multi-stage gradient duct system is arranged on the wall part of the sagger body and consists of a plurality of exhaust holes which are uniformly distributed on the inner surface and have the pore diameter of 0.5-2mm, and a macroscopic gas guide channel which is communicated with the exhaust holes, has an outlet arranged on the outer surface and has the pore diameter of 3-5mm. The sagger is integrally formed and sintered by adopting a binder injection 3D printing technology. When the sagger is used, a ceramic green body subjected to powder extrusion and 3D printing is embedded into the embedded powder in the sagger, and in the thermal degreasing process, green body decomposition gas can simultaneously diffuse upwards through the gaps of the embedded powder and be directly and efficiently discharged outwards through the gradient pore channel system. The problem of unsmooth exhaust at the bottom caused by a traditional solid sagger is fundamentally solved, the degreasing success rate and the product quality of a ceramic green body with a complex structure are remarkably improved, the structure is simple, the cost is low, and the process is stable.

Description

Technical Field

[0001] This invention relates to the field of ceramic additive manufacturing and post-processing technology, and in particular to a 3D printed porous ceramic sagger and its usage method. Background Technology

[0002] Powder extrusion 3D printing is a rapidly developing ceramic additive manufacturing technology in recent years. Based on the principle of ceramic injection molding, it mixes ceramic powder with a multi-component organic binder to form a feedstock. This feedstock is then heated and extruded layer by layer to form a green body with a complex three-dimensional structure. After debinding and sintering, the final ceramic product is obtained. This technology shows great potential in the hollow integrated design, integrated forming of complex structures, and lightweight fabrication of high-performance specialty ceramics.

[0003] However, powder extrusion 3D printing preforms contain a large amount of organic binder (typically accounting for 40%-60% of the volume), and their safe and thorough removal is a crucial step in determining the success or failure of the final product. During thermal debinding, the binder decomposes upon heating, generating a large amount of gas. If the gas cannot be discharged from the preform in a timely and smooth manner, it will accumulate inside, forming localized high pressure, leading to defects such as blistering, cracking, deformation, or even collapse. This risk is particularly prominent for complex structural parts with thick walls, large dimensions, or enclosed cavities.

[0004] Currently, powder embedding and thermal debinding is a common method for processing ceramic green bodies with such complex structures. This method involves completely embedding the green body in inert refractory powder placed within a ceramic sagger, and then gradually decomposing the binder through programmed temperature control. The powder embedding plays three main roles in this process: supporting the green body to prevent deformation, uniformly transferring heat to reduce temperature gradients, and adsorbing some liquid products. In traditional processes, the ceramic sagger—the container holding the powder embedding and the green body—is usually made using traditional ceramic techniques such as slip casting and dry pressing. Its structure is a dense, solid body, and it is considered merely a passive supporting container.

[0005] With the increasing demand for high-performance, complex-structured ceramic parts (such as ceramic turbine rotors with internal flow channels, large ceramic substrates, and porous scaffolds) in aerospace, precision electronics, and biomedical fields, the limitations of existing powder-embedded degreasing technology are becoming increasingly apparent. The fundamental problem lies in the bottleneck of the degreasing system's structural design: the walls and bottom of traditional solid ceramic saggers are completely sealed, failing to provide an active and direct exhaust channel for gases generated during decomposition at the bottom and lower sides of the green body. The gas is forced to travel upwards through the tortuous gaps between the embedded powder particles to the opening at the top of the sagger before being discharged, resulting in a long exhaust path, high resistance, and low efficiency. Especially when processing large-sized or thick-walled green bodies, gas generated in the central region of the green body tends to accumulate at the end of the exhaust path, forming a localized high-pressure zone, which is the main cause of blistering and cracking defects inside the green body.

[0006] To address the aforementioned problem of poor venting, existing technologies primarily optimize along two paths: First, focusing on improving the powder-laden material itself, such as optimizing the particle size, gradation, and material composition (as described in patents CN117362029A and CN106316369B) to improve its thermal conductivity, permeability, and adsorption performance; second, introducing complex external active venting equipment, such as constructing a forced ventilation system within the degreasing furnace to carry away decomposition products through airflow (as in scheme CN221209882U). However, the first path only provides limited improvement to the diffusion conditions of gas within the powder-laden layer and does not solve the structural bottleneck of "no way to pass" at the bottom of the solid crucible, thus only addressing the symptoms, not the root cause. While the second path enables active venting, it introduces new problems such as increased equipment complexity, higher costs, increased difficulty in process control (e.g., airflow may disturb the uniformity of the temperature field), and reduced system reliability.

[0007] Therefore, a long-standing technological bias exists in this field: the optimization of degreasing processes either focuses on improving the formulation of the powder embedding material or relies on upgrading external equipment, while the crucible itself is generally regarded as a single-function, inert container. This bias severely restricts further improvements in degreasing efficiency and yield. The market urgently needs a degreasing solution that can achieve efficient, uniform, and stable degassing without significantly increasing costs and process complexity, through fundamental innovation at the system structure level. Summary of the Invention

[0008] The first objective of this invention is to provide a 3D-printed porous ceramic sagger to overcome the problem that traditional solid ceramic saggers only serve as inert containers during the powder-burying and degreasing process, and cannot actively guide and discharge decomposed gases from the bottom and sides of the blank, thus causing defects such as bubbling and cracking in the blank due to poor exhaust.

[0009] The second objective of this invention is to provide a method for manufacturing the above-mentioned 3D-printed porous ceramic sagger, so as to solve the problem that traditional ceramic molding processes cannot manufacture saggers with complex internal through-gradient channel structures, and to achieve integrated and precise molding of this special structure.

[0010] The third objective of this invention is to provide a method for using the aforementioned 3D-printed porous ceramic sagger, in order to overcome the problems of single gas exhaust path and low efficiency in traditional powder-embedding degreasing processes, as well as the complexity, high cost, and potential process instability of external active ventilation schemes, thereby achieving efficient, uniform, and low-cost degreasing.

[0011] The technical solution of the present invention to solve the first technical problem is: a 3D printed multi-channel ceramic sagger, including a sagger body with an open top and made of refractory ceramic material, wherein the wall of the sagger body is provided with a multi-level gradient channel system that can connect the inside and outside of the sagger body, wherein the multi-level gradient channel system includes a plurality of vent holes evenly distributed on the inner surface of the sagger body, wherein the diameter of the vent holes is 0.5mm-2mm. The multi-level gradient channel system also includes a macroscopic air guide channel connected to the exhaust port. The outlet of the macroscopic air guide channel is located on the outer surface of the bowl, and the outlet diameter of the macroscopic air guide channel is 3-5 mm.

[0012] As a further improvement of the present invention, the multi-level gradient channel system is disposed on the bottom wall of the bowl.

[0013] As a further improvement of the present invention, a multi-level gradient channel system is provided on the side wall of the bowl.

[0014] As a further improvement of the present invention, the exhaust port is provided in a one-to-one correspondence with the outlet of the macroscopic air guiding channel.

[0015] As a further improvement of the present invention, the finished density of the bowl body is 1.9-2.1 g / cm³.

[0016] The technical solution of this invention to solve the second technical problem is: a method for manufacturing a 3D-printed porous ceramic sagger, comprising the following steps: S1. Structural Design: Using 3D modeling software, design a model of the bowl body with the multi-level gradient channel system pre-installed inside; S2. Additive manufacturing: Using ceramic powder as raw material, binder jet 3D printing technology is used to print a sagger blank according to the model of the sagger body designed in step S1. S3. Sintering: The sagger blanks produced in step S2 are sintered to obtain porous ceramic sagger finished products.

[0017] As a further improvement of the present invention, the ceramic powder in step S2 is alumina powder with a loose packing density of 1.6-2.0 g / cm³; the thickness of the printed layer in the binder jet 3D printing is 0.2-0.3 mm.

[0018] As a further improvement of the present invention, the sintering step S3 is carried out in a silicon molybdenum rod sintering furnace at a sintering temperature of 1480-1530°C.

[0019] The technical solution of this invention to solve the third technical problem is: a method for using a 3D printed porous ceramic sagger, used to degrease a ceramic green body printed by powder extrusion 3D printing, the method comprising the following steps: A. Prepare the aforementioned porous ceramic sagger; B. Fill the porous ceramic sagger with embedded powder and embed the ceramic green body in the embedded powder to form an embedded powder degreasing system; C. Place the powder-embedding degreasing system in a degreasing furnace for hot degreasing. In step C, during the hot degreasing process, the gas generated by the decomposition of the binder in the ceramic green body diffuses upward through the gaps between the embedded powder and is discharged outward through the multi-level gradient channel system of the porous ceramic sagger.

[0020] As a further improvement of the present invention, the embedded powder is alumina embedded powder.

[0021] Beneficial effects Compared with the prior art, the advantages of the 3D printed porous ceramic sagger and its usage method of the present invention are as follows: 1. Fundamentally solves the exhaust bottleneck, significantly improving degreasing success rate and product quality: This invention breaks away from the traditional technical prejudice of treating the sagger as a solid container. It innovatively designs and manufactures a continuous, multi-level gradient channel system on its walls (especially the bottom). This structure provides an active, short, and direct exhaust channel for thermal decomposition gases at the bottom and lower sides of the billet, fundamentally different from the traditional single-path exhaust through top-buried powder. This greatly reduces gas exhaust resistance, preventing localized gas accumulation and high pressure within the billet, thus effectively preventing defects such as bubbling and cracking caused by poor exhaust during degreasing. 2. Achieves integrated molding of complex structures and functions, breaking through the limitations of traditional manufacturing processes: The sagger described in this invention, with its fine internal gradient channels (especially the composite structure of small-diameter air inlets and macroscopic air guiding channels), cannot be achieved by traditional ceramic processes such as slip casting and dry pressing. This invention creatively employs binder jet 3D printing technology for integrated molding, a process particularly suitable for manufacturing ceramic components with complex internal channels and requiring a certain porosity. It not only achieves precise and controllable molding of the channel structure, but its process characteristics also allow the finished sagger body (non-channel part) to naturally form moderately dispersed micropores (approximately 2% porosity), further assisting in the uniform diffusion of gas and forming a dual high-efficiency exhaust mechanism of "active channel drainage + body dispersion infiltration"; 3. Simplified degreasing system, reduced costs, and improved process stability: This invention replaces the existing "active" forced ventilation scheme, which requires additional complex equipment such as gas pipelines and flow control systems, with a built-in "passive" physical exhaust structure. While achieving excellent exhaust performance, it eliminates the need for expensive external equipment, simplifies the operation process, and reduces overall costs. Simultaneously, it avoids the disturbances that forced airflow may cause to the furnace temperature field and the billet, making the degreasing process more stable and reliable, and easier to promote and apply in industrial production. 4. Structural and functional synergistic optimization, combining efficient venting with long-term reliability: In the multi-level gradient channel system, the small-diameter (0.5-2mm) venting holes facing the billet effectively prevent powder particles from entering and clogging the channels ("slag blocking function"), while the larger external air guiding channels (3-5mm) ensure rapid gas collection and discharge ("ventilation function"). This gradient design synergistically resolves the contradiction between ventilation and anti-clogging. Furthermore, the sagger, made using high-purity alumina combined with binder jet 3D printing technology, possesses excellent high-temperature strength, thermal stability, and thermal shock resistance, ensuring its structural integrity and long service life during repeated high-temperature degreasing cycles.

[0022] The invention will become clearer from the following description, taken in conjunction with the accompanying drawings, which are used to explain embodiments of the invention. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective view of the bowl body in this invention; Figure 2 This is one of the internal structural diagrams of the bowl body in this invention; Figure 3 This is the second internal structural diagram of the bowl in this invention; Figure 4 This is the third internal structural diagram of the bowl in this invention; Figure 5 This is a physical image of the 3D-printed porous ceramic sagger of the present invention; Figure 6 Comparison images of the degreased raw blanks; Figure 7 Comparison images of sintered ceramics; Figure 8 Images of degreased green blanks and sintered ceramics for 3D printing thickened and porous ceramic samples.

[0025] Wherein: 1-bowl body; 2-exhaust port; 3-macro air guide channel. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; of course, they can also refer to a mechanical connection or an electrical connection; furthermore, they can refer to a direct connection, an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0028] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0029] Example Specific embodiments of the present invention are as follows: Figure 1-2 As shown, a 3D-printed porous ceramic sagger includes a sagger body 1 with an open top, made of high-purity alumina refractory ceramic. In this embodiment, the finished density of the sagger body 1 is 1.9-2.1 g / cm³.

[0030] The bowl body 1 has a multi-level gradient channel system on its wall that connects the inside and outside of the bowl body 1. Specifically, the multi-level gradient channel system includes multiple vent holes 2 evenly distributed on the inner surface of the bowl body 1, with a diameter of 0.5mm-2mm. The multi-level gradient channel system also includes a macroscopic air guiding channel 3 connected to the vent holes 2. The outlet of the macroscopic air guiding channel 3 is located on the outer surface of the bowl body 1, and the outlet diameter of the macroscopic air guiding channel 3 is 3-5mm. In this embodiment, the multi-level gradient channel system is located on the bottom wall of the bowl body 1. Of course, as... Figure 3 As shown, in the actual manufacturing process, a multi-level gradient channel system can also be set on the bottom and side walls of the bowl 1 to further improve the exhaust effect.

[0031] Furthermore, in this embodiment, both the exhaust port 2 and the outlet of the macroscopic air guiding channel 3 are circular holes, and the exhaust port 2 and the outlet of the macroscopic air guiding channel 3 are arranged in a one-to-one correspondence. Of course, in actual manufacturing, the exhaust port 2 and the macroscopic air guiding channel 3 can be set to other shapes, and are not limited to circular holes. For example, as... Figure 4As shown, the outlets of both the exhaust port 2 and the macroscopic air guide channel 3 can be set as square holes. Furthermore, the inner surface of the exhaust port 2 and the outer surface of the macroscopic air guide channel 3 are connected by a grid-like distribution of intermediate pillars.

[0032] The method for manufacturing 3D-printed porous ceramic saggers includes the following steps: S1. Structural Design: Using 3D modeling software (such as SolidWorks), a 3D model of the bowl body 1 with a multi-level gradient channel system pre-installed inside is designed based on the above-mentioned multi-channel ceramic sagger structure. S2. Additive manufacturing: Using ceramic powder as raw material, binder jet 3D printing technology is used to print a sagger blank according to the model of the sagger body 1 designed in step S1. S3. Sintering: After microwave drying, the sagger blanks manufactured in step S2 are transferred to a silicon molybdenum rod sintering furnace for sintering to obtain porous ceramic sagger finished products.

[0033] In this embodiment, the ceramic powder used in step S2 is alumina powder with a loose packing density of 1.6-2.0 g / cm³; the thickness of the printed layer in the binder jet 3D printing is 0.2-0.3 mm. Meanwhile, the sintering temperature in step S3 is: heated to 1480-1530℃ at a rate of 5℃ / min and held at that temperature for 2 hours.

[0034] The main purpose of using a 3D-printed porous ceramic sagger is to debind the ceramic green body produced by powder extrusion 3D printing. Specifically, the method includes the following steps: A. Prepare a porous ceramic sagger with the above-described structure; simultaneously, prepare a ceramic green body—using powder extrusion 3D printing technology. The ceramic feedstock used is made by mixing ceramic powder with a multi-component organic binder; B. Fill a porous ceramic sagger with a sufficient amount of alumina powder, and then embed the ceramic green body obtained in step A into the powder according to the specifications to ensure that the green body is completely surrounded and supported, forming a complete powder embedding and degreasing system. C. Place the entire powder-embedded degreasing system into a conventional degreasing furnace. Set the heating program according to the characteristics of the green body for hot degreasing, with a maximum temperature of 300℃, and then cool it to room temperature in the furnace. In step C, during the hot degreasing process, the gas generated by the decomposition of the binder in the ceramic green body diffuses upward through the gaps between the embedded powder and is discharged outward through the multi-level gradient channel system of the porous ceramic sagger.

[0035] Afterwards, the defect-free ceramic blank obtained after successful degreasing is sintered at 1560℃ according to standard process to obtain the final ceramic part.

[0036] Regarding the manufacturing and use methods of the aforementioned porous ceramic saggers, this embodiment presents the following three specific cases.

[0037] Case 1 1) Preparation of porous ceramic saggers (1) Design a sagger model with pre-set gradient holes through the sagger using 3D modeling software. The exhaust hole 2 has a diameter of 2mm and is designed at the bottom of the sagger. The macroscopic air guide channel 3 has an outlet diameter of 3mm and is distributed on the outer surface of the bottom of the sagger. There are a total of 21×21=441 gradient holes on the bottom surface of the sagger, and the distance between the holes is 5mm.

[0038] (2) Using white corundum alumina powder as raw material, a sagger blank was manufactured using binder jet 3D printing technology. The loose density of the alumina powder was 1.9 g / cm³, the printing layer thickness was 0.24 mm, and the resolution was 0.06.

[0039] (3) After the printed sagger blank is microwave-dried, it is placed in a silicon molybdenum rod sintering furnace and sintered at 1520℃ to obtain the finished gradient channel ceramic sagger, such as Figure 5 As shown, the density of the finished product is 2.05 g / cm3.

[0040] 2) A dense ceramic green body sample of 25mm × 25mm × 5mm was prepared using powder extrusion 3D printing technology: The ceramic feedstock (a mixture of ceramic powder and organic binder) was heated, extruded, and deposited layer by layer to form a three-dimensional green body. The printing nozzle diameter was 0.8mm, the layer height was 0.15mm, and the printing speed was 40mm / s. The relatively low layer height was used to improve the interlayer bonding force and avoid delamination of the green body.

[0041] 3) Powder embedding and degreasing: In the gradient-pore ceramic sagger prepared in step 1), alumina powder is used to embed the dense ceramic green body prepared in step 2) according to specifications. The entire sagger system is placed in a conventional degreasing furnace, and thermal degreasing is performed according to the characteristics of the green body and a heating curve is set. The maximum temperature during degreasing is 300℃, and then the furnace is cooled to room temperature.

[0042] 4) The 3D printed ceramic blank obtained after degreasing is sintered at 1560℃ according to standard process to obtain the final dense ceramic part.

[0043] To verify that the above method can achieve better degreasing results, comparative examples 1 (direct thermal degreasing without using a sagger or powder embedding), 2 (degreasing using a traditional solid ceramic sagger combined with powder embedding), and 3 (thermal degreasing using a porous sagger without powder embedding) were comprehensively compared and analyzed. The degreasing rate (degreasing rate = mass difference before and after degreasing / mass before degreasing) of the powder extrusion 3D printed dense ceramic green body was calculated, and the surface defect state of the green body after degreasing and the finished product after sintering was observed. The degreasing rate and surface state of the green body are shown in the table below, and the image of the green body after degreasing is shown in [image missing]. Figure 6 See the image of the sintered ceramic. Figure 7 .

[0044] From the above table and attached Figure 6 , 7 It can be seen that using a porous sagger for degreasing can yield intact and defect-free 3D-printed dense ceramic green bodies and sintered finished products, with a significantly higher degreasing rate than traditional thermal degreasing methods. Furthermore, even without powder embedding, using only a porous sagger can achieve good degreasing results. In contrast, direct thermal degreasing results in obvious cracks after degreasing, and while no defects are observed after degreasing using the traditional solid sagger powder embedding thermal degreasing method, multiple ring-shaped cracks appear at the bottom of the green body after sintering, indicating poor bottom venting.

[0045] Case 2 1) Step 1) is the same as in Case 1.

[0046] 2) A dense ceramic green body sample of 25mm×25mm×8mm was prepared using powder extrusion 3D printing technology: The ceramic feedstock (a mixture of ceramic powder and organic binder) was heated, extruded, and deposited layer by layer to form a three-dimensional green body. The printing nozzle diameter was 0.8mm, the layer height was 0.15mm, and the printing speed was 35mm / s.

[0047] 3) Powder embedding and degreasing: In the gradient-pore ceramic sagger prepared in step 1), alumina powder is used to embed the thickened and dense ceramic green body prepared in step 2) according to specifications. The entire sagger system is placed in a conventional degreasing furnace, and thermal degreasing is performed according to the characteristics of the green body. The maximum temperature during degreasing is 300℃, and then the furnace is cooled to room temperature.

[0048] 4) The 3D printed ceramic blank obtained after degreasing is sintered at 1560℃ according to standard process to obtain the final dense ceramic part.

[0049] The debinding rate of the 3D-printed thickened (8mm thick) dense ceramic green body using a porous sagger for powder embedding and thermal debinding was 5.95%. The surface states of the 3D-printed thickened dense ceramic green body (step 2), the debinded ceramic green body (step 3), and the sintered thickened dense ceramic finished product (step 4) are shown in the figure. Figure 8 Increasing the sample thickness in Case 1 from 5mm to 8mm resulted in a slight decrease in the degreasing rate, but still yielded a perfectly intact sintered product.

[0050] Case 3 1) Step 1) is the same as in Case 1.

[0051] 2) A porous ceramic green body sample with a diameter of Ф41mm × H8mm was prepared using powder extrusion 3D printing technology: The ceramic feedstock (a mixture of ceramic powder and organic binder) was heated, extruded, and deposited layer by layer to form a three-dimensional green body. The printing nozzle diameter was 0.8mm, the layer height was 0.15mm, the filling pattern was serrated, and the printing speed was 28mm / s.

[0052] 3) Powder embedding and debinding: In the gradient-pore ceramic sagger prepared in step 1), alumina powder is used to embed the porous ceramic green body prepared in step 2) according to specifications. The entire sagger system is placed in a conventional debinding furnace, and thermal debinding is performed according to the characteristics of the green body and a heating curve is set. The maximum temperature during debinding is 300℃, and then the furnace is cooled to room temperature.

[0053] 4) The 3D printed ceramic blank obtained after degreasing is sintered at 1560℃ according to standard process to obtain the final porous ceramic part.

[0054] The debinding rate of the 3D-printed porous ceramic green body using a porous channel sagger for powder embedding and thermal debinding was 7.98%. The surface states of the 3D-printed porous ceramic green body (step 2), the debinded ceramic green body (step 3), and the sintered porous ceramic finished product (step 4) are shown below. Figure 8 This method achieves thorough degreasing of ceramic green bodies with a three-dimensional interconnected porous structure, resulting in a higher degreasing rate. The finished product after degreasing and sintering is intact and defect-free.

[0055] In summary, compared with existing technologies, this solution has the following advantages: (1) An innovative, interconnected, multi-level gradient channel system was designed and manufactured in the ceramic sagger wall. This structure provides an active, short, and direct exhaust channel for the thermal decomposition gases at the bottom and lower sides of the green body, fundamentally different from the traditional single-path exhaust method that only exhausts gases upward through top-mounted powder. This greatly reduces gas exhaust resistance and avoids the formation of high pressure due to local gas accumulation inside the green body, thus effectively preventing defects such as bubbling and cracking caused by poor exhaust during the degreasing process. Example data shows that ceramic parts sintered using the sagger system of this invention are defect-free and have a higher degreasing rate. Even without powder embedding, a good degreasing effect can be achieved using only a multi-channel sagger.

[0056] (2) The porous ceramic sagger creatively adopts binder jet 3D printing technology for integrated structural and functional molding. This process is particularly suitable for manufacturing ceramic components with complex internal channels and requiring a certain porosity. It not only achieves precise and controllable molding of the pore structure, but also its process characteristics enable the non-pore parts of the finished sagger body to naturally form moderately dispersed micropores, thereby further assisting the uniform diffusion of gas and forming a dual high-efficiency exhaust mechanism of "active pore channel drainage + body dispersion infiltration".

[0057] (3) The "passive" physical exhaust structure built into the porous ceramic sagger replaces the "active" forced ventilation scheme that requires additional complex equipment such as gas pipelines and flow control systems in the existing technology. While achieving excellent exhaust effect, it saves the investment of expensive external equipment, simplifies the operation process, and reduces the overall cost. At the same time, it avoids the disturbance that forced airflow may cause to the temperature field and billet in the furnace, making the degreasing process more stable and reliable, and easy to promote and apply in industrial production.

[0058] (4) In the multi-level gradient channel system, the small-diameter exhaust hole 2 facing the billet can effectively block the powder particles from entering the clogging channel, that is, it has the function of "slag blocking"; while the larger external macroscopic air guiding channel 3 ensures the rapid collection and discharge of gas, that is, the function of "ventilation". This gradient design solves the contradiction between ventilation and anti-clogging. In addition, the sagger made by high-purity alumina combined with binder jet 3D printing technology has excellent high-temperature strength, thermal stability and thermal shock resistance, ensuring its structural integrity and long service life in repeated high-temperature degreasing cycles.

[0059] The present invention has been described above in conjunction with the preferred embodiments, but the present invention is not limited to the embodiments disclosed above, but should cover various modifications and equivalent combinations made in accordance with the essence of the present invention.

Claims

1. A 3D-printed porous channelled ceramic saggar comprising a saggar body (1) provided with an open top and made of a refractory ceramic material, characterized in that, The wall of the sagger (1) is provided with a multi-stage gradient pore system capable of communicating the inside and outside of the sagger (1), which comprises a plurality of exhaust holes (2) uniformly distributed on the inner surface of the sagger (1), and the diameter of the exhaust holes (2) is 0.5-2 mm. The multi-stage gradient pore system further comprises a macroscopic gas guide channel (3) in communication with the exhaust holes (2), and the outlet of the macroscopic gas guide channel (3) is arranged on the outer surface of the sagger, and the outlet diameter of the macroscopic gas guide channel (3) is 3-5 mm.

2. The 3D-printed porous channelled ceramic saggar of claim 1, wherein, The multi-stage gradient pore system is arranged on the bottom wall of the sagger (1).

3. The 3D-printed porous channelled ceramic saggar of claim 1 or 2, wherein, The multi-stage gradient pore system is arranged on the side wall of the sagger (1).

4. The 3D-printed porous channelled ceramic saggar of claim 1, wherein, The exhaust holes (2) are arranged one-to-one corresponding to the outlets of the macroscopic gas guide channels (3).

5. The 3D-printed porous channelled ceramic saggar of claim 1, wherein, The finished density of the sagger (1) is 1.9-2.1 g / cm³.

6. A method of making a 3D-printed porous channelled ceramic saggar according to any one of claims 1-5, wherein, The method comprises the following steps: S1, structure design: using a three-dimensional modeling software to design a model of the sagger (1) with the multi-stage gradient pore system prearranged inside; S2, additive manufacturing: using ceramic powder as raw material, adopting a binder jetting 3D printing technology, and printing a sagger green body according to the model of the sagger (1) designed in step S1; S3, sintering: sintering the sagger green body manufactured in step S2 to obtain a multi-pore ceramic sagger product.

7. The method of claim 6, wherein the 3D-printed porous channelled ceramic saggar is characterized by, The ceramic powder in step S2 is alumina powder, and the loose bulk density thereof is 1.6-2.0 g / cm³; the printing layer thickness of the binder jetting 3D printing is 0.2-0.3 mm.

8. The method of claim 6, wherein the 3D-printed porous channelled ceramic saggar is characterized by, The sintering step in step S3 is performed in a silicon molybdenum rod sintering furnace, and the sintering temperature is 1480-1530℃.

9. A method of using the 3D printed porous channelled ceramic sintering basket of any one of claims 1-5 for debinding of a powder extruded 3D printed ceramic green body, characterized in that, The method comprises the following steps: A, preparing the multi-pore ceramic sagger according to any one of claims 1-4; B, filling the powder in the multi-pore ceramic sagger, and embedding the ceramic green body in the powder to form a powder debinding system; C, placing the powder debinding system in a debinding furnace to perform heat debinding; During the heat debinding in step C, part of the gas generated by the decomposition of the binder in the ceramic green body diffuses upward through the powder gaps, and part of the gas diffuses outward through the multi-stage gradient pore system of the multi-pore ceramic sagger.

10. The method of using a 3D-printed porous channelled ceramic saggar of claim 9, wherein, The powder is alumina powder.

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