Composite melting process multi-material ceramic co-printing forming method and device

Abstract

The application belongs to the field of ceramic 3D printing, and specifically provides a composite melting process multi-material ceramic combined printing forming method and device. The device comprises a switchable light curing system and an FDM nozzle system, a movable double tank and a processing platform. Through the method and device provided by the application, two or more ceramic slurry core gradients can be combined to form, the characteristics of different proportions of ceramic slurry can be reasonably utilized, and the printing efficiency and printing quality of the ceramic core can be improved. At the same time, the FDM technology is used to increase the support inside the weak part of the complex ceramic core, reduce the shrinkage rate in the subsequent sintering process, and finally realize the high-performance forming of the high-temperature alloy single crystal blade. The device and method can solve the problems of high sintering shrinkage rate and low size precision of the current 3D printing complex ceramic core, and have important significance for improving the production efficiency of ceramic 3D printing.

Description

Technical Field

[0001] This invention belongs to the field of ceramic 3D printing, and in particular relates to a method and apparatus for the combined printing and forming of multi-material ceramics using a composite melting process. Background Technology

[0002] Ceramic photopolymerization is widely used in the manufacture of cores for hollow turbine blades in advanced aero-engines due to its excellent performance. Ceramic slurry, as an important raw material for photopolymerization of ceramic cores, has viscosity and solid content that are key characteristics affecting photopolymerization efficiency and core quality.

[0003] The viscosity of ceramic slurry refers to its fluidity characteristics, directly affecting the accuracy and speed of the printing process. Excessive viscosity can lead to nozzle clogging, uneven layer thickness, and defects. The solid content of ceramic slurry refers to the amount of solid particles it contains. Higher solid content can improve the density and mechanical properties of the printed material, but it also increases the viscosity of the slurry. This leads to a contradictory relationship between viscosity and solid content in ceramic slurry: increasing solid content can improve the quality of the printed material, but it also increases the viscosity of the slurry, reducing printing stability and fluidity. In pursuit of lower viscosity and improved photopolymerization efficiency, a lower solids content in the ceramic slurry results in a larger shrinkage rate after debinding and sintering, making the sample more prone to deformation and cracking during sintering, and increasing the likelihood of core breakage and leakage during actual production casting.

[0004] Current photopolymerization processes for ceramic cores all use only a single ceramic slurry, which limits the overall forming efficiency and quality of the ceramic core. Especially for ceramic cores with complex shapes, different areas have different wall thicknesses and application conditions, and different requirements for shrinkage rate and dimensional accuracy. Using a single slurry makes it difficult to ensure that the photopolymerization forming of each part and the subsequent debinding and sintering can achieve good quality, thus affecting the overall forming efficiency and quality of the core.

[0005] For high-precision photopolymerization molding of ceramic cores, various ceramic slurry systems can be designed based on different component ratios. Then, according to the different performance focuses of different areas of the core, the most suitable ceramic slurry for each area is selected to achieve photopolymerization molding of ceramic cores using multiple slurries.

[0006] Furthermore, for complex ceramic cores formed using photopolymerization, in addition to considering precise forming during the photopolymerization process, it is even more important to reduce or avoid shrinkage deformation during the subsequent debinding and sintering process. Current photopolymerization processes for ceramic cores mainly control deformation during the debinding and sintering process to some extent by adjusting the solid content of the ceramic slurry. However, this affects the viscosity of the ceramic slurry, which in turn affects the accuracy of the photopolymerization forming. Summary of the Invention

[0007] To address the aforementioned problems, this invention discloses a multi-material ceramic printing method and apparatus using a composite melting process, solving the issues of high sintering shrinkage and low dimensional accuracy in current 3D printing of complex ceramic cores. The method and apparatus provided by this invention enable the combined forming of two or more ceramic slurries in a gradient manner, rationally utilizing the characteristics of different proportions of ceramic slurries to improve the printing efficiency and quality of the ceramic core. Simultaneously, by utilizing FDM technology, internal supports are added to the weak points of the complex ceramic core, reducing the shrinkage rate during subsequent sintering, ultimately achieving high-performance forming of high-temperature alloy single-crystal blades.

[0008] This composite melting process multi-material ceramic co-printing molding device includes a frame, a switchable photopolymerization system and FDM printhead system, a movable dual material tank, and a processing platform. Above the frame are X1 and X2 axis guide rails, coordinated by a connector. Linear sliding mechanisms one and two are connected between these two guide rails, each housing the FDM printhead system and the SLA photopolymerization light source, respectively. Below the frame are X3 and X4 axis guide rails, also connected by a connector. Material tanks one and two are placed between these two guide rails. In the center of the frame, a Z-axis and a liquid level axis are mounted side-by-side. The Z-axis drives the connecting block, tray, and printing platform via a slider, while the liquid level axis drives the connecting block and balance block via a slider.

[0009] Furthermore, the X3-axis and X4-axis guide rails have sufficient travel to allow material tank one and material tank two to move left and right to the bottom of the printing platform, enabling the switching of different ceramic slurries.

[0010] Furthermore, the first and second linear sliding mechanisms can move left and right along the X1 and X2 axis guide rails, thereby driving the movement of the FDM printhead system and the SLA photopolymerization light source to achieve the switching of different printing processes.

[0011] The main innovation of this device is that the movement of the upper slide rail enables the switching between the FDM printhead system and the SLA light curing light source, thereby combining the two printing methods for joint molding; while the lower slide rail enables the switching between different SLA pastes.

[0012] This invention also proposes a method for the combined printing and forming of multi-material ceramics using a composite melting process, which includes the following steps: Step 1: Before printing begins, analyze the sample and match ceramic slurry with different properties according to the precision requirements and sintering shrinkage requirements of different parts of the sample; design internal supports for weak parts of the sample. Step 2: Before printing begins, raise both the printing platform and the counterweight to their highest points. Move material tank one directly below the printing platform, with material tank two to its right. Manually add the ceramic slurry to be printed to material tanks one and two respectively, until the slurry level is flush with the upper surfaces of material tanks one and two. Move the printing platform and counterweight downwards until they are flush with the upper surface of material tank one. Because the printing platform has a grid structure, the ceramic slurry can flow through the grid. Finally, the upper surface of the printing platform is flush with the slurry and immersed in the ceramic slurry. Manually install the selected filament for support onto the FDM printhead system. Step 3: Import the model to be printed and slice it using the host computer software; when slicing, for the parts that need to be supported by FDM technology, corresponding holes need to be reserved during modeling to facilitate the establishment of internal supports; for parts using different ceramic pastes, the appropriate layer thickness can be set according to the characteristics of the ceramic paste. Step 4: Start printing. Taking the printing of two ceramic slurries A and B as an example, slurry A is loaded into slurry 1, and slurry B is loaded into slurry 2. First, print the part using ceramic slurry A layer by layer according to the slicing results, following these principles: the light curing light source cures the printing area layer by layer; after each layer is cured, the Z-axis drives the printing platform to descend by the thickness of one layer; the liquid level sensor monitors the liquid level of the ceramic slurry in real time, and controls the balance block through the liquid level axis to adjust the liquid level to ensure that the printed layer is flush with the liquid level surface; ceramic slurry A flows through the grid-like printing platform, and the linear sliding mechanism 3 drives the scraper to scrape off the excess printing material; Step 5: Print the portion using ceramic paste B layer by layer, specifically including: the Z-axis and liquid level axis respectively drive the printing platform and balance block to rise until the bottom surface is higher than the upper surface of material tank one and material tank two; material tank one and material tank two move to the right along the X3 axis guide rail and X4 axis guide rail until material tank two is exactly below the printing platform; the Z-axis and liquid level axis respectively drive the printing platform and balance block to descend to the printing height; complete the printing of the portion using ceramic paste B layer by layer according to step 4; Step 6: During the printing process according to Steps 4 and 5, for the parts requiring internal support, the FDM printhead system is used to print the internal support. Specifically, this includes: the linear sliding mechanism 2 moves the photopolymer light source system to the left along the X1 and X2 axis guide rails, while the linear sliding mechanism 1 moves the FDM printhead system to the left and directly above the printing platform; the Z-axis moves the printing platform up to the initial melting and printing layer; the industrial control computer controls the FDM printhead system to move to the initial printing position along the X1 and X2 axis guide rails and the linear sliding mechanism 1; zero-layer printing is performed; after a single layer is printed, the printing platform moves down one layer thickness distance to print the next layer; this process is repeated layer by layer to complete the printing of the internal support part. Step 7: Based on the principles of layer-by-layer printing, changing ceramic slurry, and adding support using FDM technology in Steps 4, 5, and 6, layers are stacked until the final printing is completed, realizing the model manufacturing of multi-material ceramics using composite melting process.

[0013] Furthermore, based on different formulations and proportions of the slurry, which have different properties such as viscosity and solids content, it is possible to adapt to the different requirements of different regions of complex ceramic cores for the precision and processing efficiency of photocuring, as well as the shrinkage requirements of the subsequent debinding and sintering process.

[0014] Furthermore, FDM technology is used to add internal supports to weak points in complex ceramic cores, reducing the shrinkage rate in these areas during subsequent sintering and ensuring the overall quality of the ceramic core. The beneficial effects of this invention are: 1. It can achieve multi-material, high-precision, and high-speed forming of complex ceramic cores. Based on the requirements of different parts of the sample for local shrinkage rate, processing accuracy, and core removal operation, ceramic slurries with different solid content, viscosity and other properties are selected to meet the needs of using multiple materials to improve the overall performance of the ceramic core structure.

[0015] 2. The composite FDM printing process adds internal support to the weak parts of complex ceramic cores, further reducing the shrinkage rate after subsequent sintering, ensuring the quality of weak parts, and realizing the printing and forming of complex ceramic cores. The FDM printing process can also print external supports, improving support printing efficiency and facilitating subsequent support removal. At the same time, it also helps to print complex hollow ceramic cores by photopolymerization, realizing the lightweight forming of complex ceramic cores.

[0016] 3. By using FDM technology, internal support is increased, reducing the overall shrinkage and deformation during subsequent debinding and sintering. This, to some extent, breaks the contradictory relationship between the solid content and viscosity of the ceramic slurry, reducing the requirements for the solid content characteristics of the ceramic slurry. Attached Figure Description

[0017] Figure 1 This is a schematic diagram (1) of the multi-material ceramic co-printing forming device for the composite melting process described in the embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram (2) of the multi-material ceramic co-printing forming device for the composite melting process described in the embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the Z-axis and printing platform in an embodiment of the present invention.

[0020] Figure Descriptions: 1-Light curing light source system; 2-FDM printhead system; 3-Coupling 1; 4-Linear sliding mechanism 1; 5-Coupling 2; 6-Frame; 7-Linear sliding mechanism 3; 8-X3 axis slide rail; 9-Balance block; 10-Scraper; 11-Material tank 1; 12-Baffle; 13-Material tank 2; 14-Panel; 15-X1 axis slide rail; 16-X4 axis slide rail; 17-Z-axis; 18-Liquid level axis; 19-X2 axis slide rail; 20-Linear sliding mechanism 2; 21-Linear interactive mechanism motor; 22-Liquid level axis motor; 23-Connecting block 2; 24-Printing platform; 25-Connecting block 1; 26-Z-axis motor. Implementation

[0021] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0022] This embodiment takes a model using two ceramic slurries, A and B, and adds support to the part using ceramic slurry B as an example: Before printing begins, ceramic slurry A is manually added to slurry 1 and ceramic slurry B is added to slurry 2. At the same time, the FDM material box to be used is loaded and the filament is threaded through the nozzle extrusion port.

[0023] Among them, such as Figure 1-3 As shown, the composite melting process multi-material ceramic printing forming device includes a frame 6; X1 axis guide rail 15 and X2 axis guide rail 19 are symmetrically arranged above the frame 6, and are coordinated by a connector to ensure consistent movement of the guide rails. Linear sliding mechanism 1 4 and linear sliding mechanism 20 are connected between these two guide rails, and FDM nozzle system 2 and SLA light curing light source 1 are respectively mounted on them; X3 axis guide rail 8 and X4 axis guide rail 16 are also symmetrically arranged below the frame 6, and connector 2 is connected to the frame 6. Material tank 1 11 and material tank 2 13 are placed between these two guide rails. Linear sliding mechanism 3 7 is fixed to the two material tanks, which drives the scraper 10 to move back and forth; in the middle of the frame 6, there is a device for printing the part using ceramic slurry B, and Z axis 17 and liquid level axis 18 are installed side by side. Z axis 17 drives connecting block 1 25, tray 14 and printing platform 24 through a slider. Liquid level axis 18 drives connecting block 2 23 and balance block 9 through a slider.

[0024] The Z-axis 17 and the liquid level axis 18 respectively drive the printing platform 24 and the balance block 9 to rise to a position where the bottom surface is higher than the upper surfaces of material tank 11 and material tank 2 13; material tank 11 and material tank 2 13 move to the right along the X3 axis guide rail 8 and the X4 axis guide rail 16 until material tank 2 13 is directly below the printing platform 24; the Z-axis 17 and the liquid level axis 18 respectively drive the printing platform 24 and the balance block 9 to descend to the printing height; During operation: After loading the material, the sliced ​​model is uploaded, and the printing platform and balance block rise to their highest points. Material tank one is moved directly below the printing platform, with material tank two positioned to its right. Simultaneously, the photopolymerization light source system moves directly above the printing platform, and the focus plane is adjusted. The FDM nozzle system moves to one side, ready to begin printing the 0th layer, which is the model base. Driven by the motor, the Z-axis and liquid level axis lower the printing platform and balance block until they are flush with the upper horizontal plane of material tank one, with their surfaces immersed in ceramic slurry A. Under the illumination of the photopolymerization light source, the ceramic slurry is cured in a portion of the grid on the printing platform to form the zeroth cured layer.

[0025] Based on the slicing results, the portion using ceramic slurry A is printed layer by layer. After each layer is cured, the Z-axis drives the printing platform to descend by the thickness of one layer. During the printing process, the liquid level sensor monitors the liquid level of the ceramic slurry in real time and controls the balance block through the liquid level axis to adjust the liquid level to ensure that the printed layer is flush with the liquid level surface. Ceramic slurry A flows through the grid-like printing platform, while the linear sliding mechanism 3 drives the scraper to remove excess printing material. The printing is carried out layer by layer until the printing of the portion using ceramic slurry A is completed.

[0026] Next, prepare to switch to ceramic slurry B. The Z-axis and liquid level axis will drive the printing platform and balance block to rise until the bottom surface is higher than the upper surface of material tank one and material tank two. Material tank one and material tank two will move to the right along the X3 axis guide rail and the X4 axis guide rail until material tank two is directly below the printing platform. The Z-axis and liquid level axis will drive the printing platform and balance block to descend to the printing height. Then, print the ceramic slurry B part layer by layer according to step 4.

[0027] When printing reaches the part requiring additional internal support, the photopolymerization printing stops. Linear sliding mechanism 2 moves the photopolymerization light source system to the left along the X1 and X2 axis guides, while linear sliding mechanism 1 moves the FDM printhead system to the left, directly above the printing platform. The Z-axis raises the printing platform to the initial melt-printing layer. The industrial computer controls the FDM printhead system to move along the X-axis (X1 and X2 axis guides) and Y-axis (linear sliding mechanism 1) to the initial printing position. Then, zero-layer printing is performed. After a single layer is printed, the printing platform moves down one layer thickness to print the next layer. This process is repeated layer by layer to complete the printing of the internal support portion. After the internal support printing is completed, the FDM printhead stops working. Linear sliding mechanism one moves the FDM printhead system to the right along the X1 and X2 axis guide rails. At the same time, linear sliding mechanism two moves the photocuring light source system to the left and directly above the printing platform. The Z-axis moves the printing platform to the current initial layer of photocuring printing. Continue with the photopolymerization printing of ceramic slurry B, layer by layer, until the printing is completed, realizing the model manufacturing of multi-material ceramics through composite melting process.

[0028] Based on the above, during the printing process, the ceramic paste is changed according to the model analysis and slicing, and internal support is increased by using FDM technology. The printing is carried out layer by layer to finally complete the target part.

[0029] The above methods allow for the combined molding of two or more ceramic slurries in a gradient ceramic core, effectively utilizing the characteristics of different slurry ratios to improve printing efficiency and quality. Simultaneously, by adding internal supports to weak points in complex ceramic cores, shrinkage during subsequent sintering is reduced, thus enhancing the overall quality of the ceramic core.

[0030] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A composite melting process multi-material ceramic co-printing forming device, comprising a frame (6); characterized in that: The frame (6) is symmetrically equipped with X1 axis guide rails (15) and X2 axis guide rails (19) above it, and the guide rails move in unison through a connector. Linear sliding mechanism one (4) and linear sliding mechanism two (20) are connected between these two guide rails, and FDM nozzle system (2) and SLA light curing light source (1) are respectively mounted on them. Similarly, the frame (6) is symmetrically equipped with X3 axis guide rails (8) and X4 axis guide rails (16) and connector two below it, with material trough one (11) and material trough two (13) placed between these two guide rails. In the middle of the frame (6), a Z-axis (17) and a liquid level axis (18) are installed side by side. The Z-axis (17) drives the connecting block (25), the tray (14), and the printing platform (24) through a slider. The liquid level axis (18) drives the connecting block (23) and the balance block (9) through a slider. The printing platform (24) and the balance block (9) are located in the middle position of the Y-axis and can be completely accommodated in the material trough in the middle position. The linear sliding mechanism (7) is fixed on the material trough (11) and the material trough (13) and is used to drive the scraper (10) to move.

2. The composite melting process multi-material ceramic co-printing forming device according to claim 1, characterized in that: The X3 axis guide rail (8) and X4 axis guide rail (16) have a stroke of 3 times the width of the material groove, which can accommodate the material groove one (11) and material groove two (13) to move left and right to below the printing platform (24).

3. A method for co-printing and forming multi-material ceramics using a composite melting process, based on the co-printing and forming apparatus for multi-material ceramics using a composite melting process as described in any one of claims 1-2, characterized in that, The method includes the following steps: Step 1: Before printing begins, analyze the sample and match ceramic slurry with different properties according to the precision requirements and sintering shrinkage requirements of different parts of the sample; design internal supports for weak parts of the sample. Step 2: Before printing begins, both the printing platform (24) and the balance block (9) are raised to their highest points. The first material tank (11) is moved directly below the printing platform (24), and the second material tank (13) is located to its right. The ceramic slurry to be printed is manually added to the first material tank (11) and the second material tank (13) until the liquid level of the ceramic slurry is level with the upper horizontal plane of the first material tank (11) and the second material tank (13). The printing platform (24) and the balance block (9) are moved down until they are level with the upper horizontal plane of the first material tank (11). The printing platform (24) is designed with a grid structure to ensure that the ceramic slurry can flow through the grid. Finally, the upper surface of the printing platform (24) is level with the liquid level and is immersed in the ceramic slurry. The selected filament for support is manually installed on the FDM nozzle system (2). Step 3: Import the model to be printed and slice it using the host computer software; before slicing, for weak parts that need to be supported by FDM technology, corresponding holes need to be reserved during modeling to facilitate the establishment of internal supports; for parts using different ceramic pastes, the appropriate layer thickness can be set according to the characteristics of the ceramic paste. Step 4: Start printing. Taking the printing of two ceramic slurries A and B as an example, slurry tank 1 (11) is loaded with ceramic slurry A and slurry tank 2 (13) is loaded with ceramic slurry B. First, print the part using ceramic slurry A layer by layer according to the slicing results, following the principles: SLA light curing light source (1) cures the printing area layer by layer; for each layer cured, the Z-axis drives the printing platform to descend by the thickness of one layer; the liquid level sensor monitors the liquid level of the ceramic slurry in real time, and controls the balance block (9) through the liquid level axis (18) to adjust the liquid level to ensure that the printing layer is flush with the liquid level surface; ceramic slurry A flows through the grid-shaped printing platform (24), and the linear sliding mechanism 3 (7) drives the scraper (10) to scrape off the excess printing material; Step 5: Print the part using ceramic paste B layer by layer, specifically including: the Z-axis (17) and the liquid level axis (18) respectively drive the printing platform (24) and the balance block (9) to rise to a position where the bottom surface is higher than the upper surface of material tank one (11) and material tank two (13); material tank one (11) and material tank two (13) move along the X3 axis guide rail (8) and the X4 axis guide rail (16) until material tank two (13) is directly below the printing platform (24); the Z-axis (17) and the liquid level axis (18) respectively drive the printing platform (24) and the balance block (9) to descend to the printing height; complete the printing of the part using ceramic paste B layer by layer according to step 4; Step 6: During the printing process according to Step 4 and Step 5, for the parts that need to be added with internal support, the FDM printhead system is used to print the internal support. Specifically, the following steps are taken: the linear sliding mechanism 2 (20) drives the SLA curing light source (1) to move to the left along the X1 axis guide rail (15) and the X2 axis guide rail (19), while the linear sliding mechanism 1 (4) drives the FDM printhead system (2) to move to the left and directly above the printing platform (24); the Z axis (17) drives the printing platform (24) to rise to the initial layer of melt printing; the motor controls the FDM printhead system (2) to move to the initial printing position along the X1 axis guide rail (15) and the X2 axis guide rail (19) and the linear sliding mechanism 1 (4); zero-layer printing is performed; after the single-layer printing is completed, the printing platform (24) moves down by one layer thickness distance to print the next layer; this process is repeated layer by layer to complete the printing of the internal support part. Step 7: Based on the principles of layer-by-layer printing, changing ceramic slurry, and adding support using FDM technology in Steps 4, 5, and 6, layers are stacked until the final printing is completed, realizing the model manufacturing of multi-material ceramics using composite melting process.

4. The method for multi-material ceramic co-printing forming using a composite melting process according to claim 3, characterized in that: FDM technology is used to add internal support to weak points in complex ceramic cores, reducing the degree of deformation in these areas during subsequent sintering and ensuring the overall quality of the ceramic core.

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