A method and equipment for layer-by-layer inkjet printing of ceramic materials

Abstract

This application relates to a method and apparatus for layer-by-layer inkjet printing of ceramic materials. The method includes the following steps: printing a first layer of ceramic green body; heating the ceramic green body to preliminarily shape it; scanning the morphology of the upper surface of the heated ceramic green body and comparing it with an ideal model; modifying and micro-sculpting the upper surface of the ceramic green body according to the comparison results to make its hydrophilicity and roughness close to the ideal model; repeating the above steps to print ceramic component green bodies sequentially from bottom to top until a complete ceramic component green body is obtained; removing the water-soluble support material from the surface of the ceramic green body; and sintering the ceramic green body to obtain the finished ceramic component. This invention combines inkjet printing additive manufacturing technology with laser processing subtractive manufacturing technology, which can correct the cumulative height error in the additive manufacturing process and modify the surface microstructure of the deposition surface, thereby improving the manufacturing accuracy and quality of ceramic parts.

Description

Technical Field

[0001] This application relates to the field of ceramic additive manufacturing technology, and in particular to a method and equipment for layer-by-layer inkjet printing of ceramic materials. Background Technology

[0002] Custom production of high-precision, multi-material complex ceramic components is in high demand in fields such as aerospace, machinery manufacturing, and biomedicine. Additive manufacturing technology is an effective way to customize complex ceramic components. Among them, ceramic inkjet printing is widely used in ceramic component production due to its high forming accuracy and ability to produce multi-material components.

[0003] Currently, ceramic inkjet printing additive manufacturing has the following drawbacks:

[0004] 1. The amount and uniformity of inkjet during the printing process cannot be accurately controlled. As the number of layers in inkjet additive manufacturing increases, the error in the amount of inkjet will accumulate and increase, resulting in an increase in the dimensional error in the height direction. Furthermore, due to the unevenness of the amount of inkjet at various locations, the cumulative effect will increase the shape error of the upper surface.

[0005] 2. The surface microstructure obtained by ceramic ink deposition in inkjet printing additive manufacturing is difficult to control, which will have an adverse effect on the strength and density of inkjet additive manufactured ceramic components. Summary of the Invention

[0006] Therefore, it is necessary to provide a method and equipment for layer-by-layer inkjet printing of ceramic materials to overcome the defects mentioned in the background art.

[0007] A method for layer-by-layer inkjet printing of ceramic materials includes the following steps:

[0008] Step 1: Print the first layer of ceramic green body, and heat this layer of ceramic green body to initially set its shape;

[0009] Step 2: Scan the morphology of the upper surface of the heated ceramic green body and compare it with the ideal model;

[0010] Step 3: Based on the comparison results, modify and microstructure the upper surface of the ceramic green body to make its hydrophilicity and roughness close to the ideal model;

[0011] Step 4: Repeat step 3 until you get a complete ceramic component green body.

[0012] Step 5: Remove the water-soluble support material from the surface of the ceramic green body;

[0013] Step 6: Sinter the ceramic green body to obtain the finished ceramic component.

[0014] As a preferred embodiment of the layer-by-layer inkjet printing method for ceramic materials in this invention, step three specifically includes:

[0015] The ceramic green body is moved to the laser processing position, and the comparison results from step two are used to control the galvanometer and external optical path to correct and engrave the microstructure on the upper surface of the ceramic green body.

[0016] The specific modifications include,

[0017] The actual height of the top surface of the current printed layer is compared with the theoretical height. When the actual height is less than the theoretical value, the difference between the two is recorded and compensated by increasing the number of printed layers. When the actual height is greater than the theoretical value, the top of the green blank is ablated using preset laser processing parameters to remove the excess protrusion on the top of the green blank.

[0018] The microstructure engraving includes,

[0019] To improve the structural strength of ceramic components, an infrared picosecond laser is used to scan parallel lines perpendicular to the extension direction of the ridges and grooves on the upper surface of the green body, so that a scaly structure appears on the upper surface of the ceramic green body.

[0020] To reduce the surface roughness of ceramic components, use an infrared picosecond laser to repeatedly scan the raised areas until all the raised areas are removed.

[0021] As a preferred embodiment of the layer-by-layer inkjet printing method for ceramic materials in this invention, in the scaly structure, each scaly protrusion is approximately 50 μm long, 40 μm wide, and 20 μm high.

[0022] As a preferred embodiment of the layer-by-layer inkjet printing method for ceramic materials in this invention, step five specifically includes:

[0023] Immerse the ceramic green body in pure water for 1 hour to remove water-soluble support material, and then let it stand in the air for 3 hours to dry naturally.

[0024] An apparatus for a layer-by-layer inkjet printing process for ceramic materials includes a mounting frame, a two-dimensional motion platform provided at the lower part of the mounting frame along its axial direction, and a printing module, a heating lamp module, a detection module and a laser module sequentially provided at the upper part of the mounting frame along its axial direction. The apparatus also includes a host computer for controlling the two-dimensional motion platform, the printing module, the heating lamp module, the detection module and the laser module.

[0025] As a preferred embodiment of the device described in this invention, the two-dimensional motion platform is provided with a worktable on top, which includes a support. The support is fixedly connected to the two-dimensional motion platform, and the top of the support is provided with a heat insulation layer and a manufacturing substrate.

[0026] As a preferred embodiment of the device described in this invention, the printing module includes a motion Y-axis mounting bracket, which is fixedly connected to the mounting frame. A motion Y-axis hanging basket is provided below the motion Y-axis mounting bracket and is slidably connected thereto. An inkjet printing head is provided on the motion Y-axis hanging basket.

[0027] As a preferred embodiment of the device described in this invention, the heating lamp module includes a heating lamp mounting bracket, which is fixedly connected to the mounting bracket, and the heating lamp is provided on the heating lamp mounting bracket.

[0028] As a preferred embodiment of the device described in this invention, the detection module includes a detection head mounting bracket, which is fixedly connected to the mounting frame. The detection head mounting bracket is provided with a laser triangulation detection head, which is connected to a host computer through an external signal processing module.

[0029] As a preferred embodiment of the device described in this invention, the laser module includes a galvanometer mounting bracket, which is fixedly connected to the mounting bracket. A galvanometer is provided on the galvanometer mounting bracket, and the light inlet of the galvanometer is connected to an external optical path. It is connected to a host computer through an external processing module.

[0030] The beneficial effects of this invention are:

[0031] This invention combines inkjet printing additive manufacturing technology with laser processing subtractive manufacturing technology, which can correct the cumulative height error in the additive manufacturing process and modify the surface microstructure of the deposition surface, thereby improving the manufacturing precision and quality of ceramic parts. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application 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 this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is one of the structural schematic diagrams of the device in the embodiments of this application;

[0034] Figure 2 This is a second schematic diagram of the device structure in the embodiments of this application;

[0035] Figure 3 One of the structural schematic diagrams of the printing module in this application embodiment;

[0036] Figure 4 The second schematic diagram of the printing module in this application embodiment;

[0037] Figure 5 This is a schematic diagram of the printing module in operation in an embodiment of this application;

[0038] Figure 6 This is a schematic diagram of the heating lamp module in operation according to an embodiment of this application;

[0039] Figure 7 This is a schematic diagram of the detection module in operation in an embodiment of this application;

[0040] Figure 8 This is a schematic diagram of the laser module in operation in an embodiment of this application;

[0041] Explanation of reference numerals in the attached figures:

[0042] 1. Mounting bracket;

[0043] 2. Two-dimensional motion platform; 21. Motion X-axis; 22. Motion X-axis slider; 23. Motion Z-axis; 24. Motion Z-axis slider

[0044] 3. Printing module; 31. Motion Y-axis mounting bracket; 32. Motion Y-axis hanging basket; 33. Inkjet print head; 34. Motion Y-axis motor; 35. Guide rod; 36. Lead screw;

[0045] 4. Heating lamp module; 41. Heating lamp mounting bracket; 42. Heating lamp;

[0046] 5. Detection module; 51. Detection head mounting bracket; 52. Laser triangulation detection head;

[0047] 6. Laser module; 61. Galvanometer mounting bracket; 62. Galvanometer;

[0048] 7. Workbench; 71. Support; 72. Heat insulation layer; 73. Manufacturing substrate;

[0049] 8. Green ceramic components. Detailed Implementation

[0050] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0051] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0053] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0054] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0055] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0056] Example

[0057] This embodiment provides a method for layer-by-layer inkjet printing of ceramic materials, and also provides an apparatus for implementing the above-mentioned method for layer-by-layer inkjet printing of ceramic materials, so as to overcome the defects of large cumulative error, poor strength and density in existing ceramic inkjet printing additive manufacturing.

[0058] like Figure 1 and Figure 2 As shown, the device includes a mounting frame 1, a two-dimensional motion platform 2 is provided on the lower part of one side of the mounting frame 1, and a printing module 3, a heating lamp module 4, a detection module 5 and a laser module 6 are arranged sequentially on the upper part of the mounting frame along its axial direction. A worktable 7 that can slide along its axial direction is provided on the two-dimensional motion platform 2.

[0059] The workbench 7 includes a support 71, which is connected to the two-dimensional motion platform 2. The top of the support 71 is provided with a heat insulation layer 72 and a manufacturing substrate 73 from bottom to top. The manufacturing substrate 73 has holes for installing heating rods and thermocouples, which can heat and control the temperature of the manufacturing substrate 73.

[0060] The two-dimensional motion platform 2 includes a motion X-axis 21, one end of which is fixedly connected to the mounting frame 1, and the other end of which is provided with a motion X-axis slider 22 slidably connected to it. The end of the motion X-axis slider 22 away from the motion X-axis 21 is provided with a motion Z-axis 23 fixedly connected to it. The motion Z-axis 23 is connected to the bracket 71 along with the motion Z-axis slider 24 slidably connected to it. The worktable 7 can slide along the X-axis and Z-axis directions of the mounting frame 1 under the drive of the two-dimensional motion platform 2.

[0061] like Figure 3 and Figure 4As shown, the printing module 3 includes a Y-axis mounting bracket 31 and a Y-axis hanging basket 32, which are fixed on the mounting bracket 1. The Y-axis mounting bracket 31 is equipped with a Y-axis motor 34, and its output end is equipped with a lead screw 36. The lead screw 36 can rotate under the drive of the Y-axis motor 34. Guide rods 35 are provided on both sides of the lead screw 36. The Y-axis hanging basket 32 ​​is slidably connected to the guide rods 35 through sliding bearings, and is also screwed to the lead screw 36. The Y-axis hanging basket 32 ​​can move along the guide rods 35 under the rotation of the lead screw 36. The Y-axis hanging basket 32 ​​is equipped with inkjet printheads 33. The ink inlet and outlet of the inkjet printheads 33 are connected to the external ink path. One inkjet printhead 33 sprays ceramic ink, and the other inkjet printhead 33 sprays water-soluble support material ink. The control line of the inkjet printheads 33 is connected to the host computer through an external control board.

[0062] The heating lamp module 4 includes a heating lamp mounting bracket 41, which is fixedly connected to the mounting bracket 1, and a heating lamp 42 is provided on the heating lamp mounting bracket 41.

[0063] The detection module 5 includes a detection head mounting frame 51, which is fixedly connected to the mounting frame 1. The detection head mounting frame 51 is equipped with a laser triangulation detection head 52, which is connected to the host computer through an external signal processing module.

[0064] The laser module 6 includes a galvanometer mounting bracket 61, which is fixedly connected to the mounting bracket 1. A galvanometer 62 is provided on the galvanometer mounting bracket 61. The light inlet of the galvanometer 62 is connected to an external optical path and is connected to a host computer through an external processing module.

[0065] The method for layer-by-layer inkjet printing of ceramic materials includes the following steps:

[0066] S1: Heat the manufacturing substrate 73 to 170°C, supply ink to the inkjet printer head 33 via the external ink path, and power on the laser triangulation head 52 and the galvanometer 62 for self-test.

[0067] S2: By moving the Y-axis basket 32 ​​of the two-dimensional motion platform 2 and the inkjet printing module 3, the worktable 7 and the inkjet print head 33 are moved to the position as shown. Figure 5 At the starting position of the printing process, the X-axis 21 drives the worktable 7 to move at a constant speed. The inkjet print head 33 selectively sprays ink when the worktable 7 moves to the appropriate position until the worktable 7 moves to the printing termination position.

[0068] S3: The two-dimensional motion platform 2 moves the worktable 7 to the position shown in the image. Figure 6 At the heating start position shown, the heating lamp 42 is activated, and the X-axis 21 drives the worktable 7 to move at a constant speed until the worktable 7 moves to the heating end position, at which point the heating lamp 42 is turned off.

[0069] S4: The two-dimensional motion platform 2 moves the worktable 7 to the position shown in the image. Figure 7 At the detection start position shown, the laser triangulation head 52 starts, and the moving X-axis 21 drives the worktable 7 to move at a constant speed. At the same time, the laser triangulation head 52 scans the morphology of the upper surface of the ceramic component green 8 and models it in the host computer until the worktable 7 moves to the detection end position, at which point the laser triangulation head 52 stops scanning.

[0070] S5: The two-dimensional motion platform 2 moves the worktable 7 to the position shown in the image. Figure 8 As shown in the laser processing position, the host computer controls the galvanometer 62 and external optical path to correct and microstructure the upper surface of the ceramic component green body 8 based on the comparison results between the morphology of the upper surface of the ceramic component green body 8 measured in S4 and the ideal model. In actual processing, the common results of the morphology test of the upper surface of the ceramic component green body 8 in S4 are: periodic ridges and grooves extending parallel to the X direction of motion appear on the upper surface of the green body, with a peak-valley height difference of 20μm and a peak-to-peak distance of 50μm. At this time, the laser processing parameters are planned according to the process requirements.

[0071] The specific modifications include:

[0072] The actual height of the top surface of the current printed layer is compared with the theoretical height. When the actual height is less than the theoretical value, the difference between the two is recorded and compensated by increasing the number of printed layers. When the actual height is greater than the theoretical value, the top of the green blank is ablated using preset laser processing parameters to remove the excess protrusion on the top of the green blank.

[0073] The structural carving includes:

[0074] To improve the structural strength of the printed parts, use an infrared picosecond laser (wavelength 1035nm, frequency 1800kHz) at 40% power, perpendicular to the extension direction of the ridges and grooves (i.e., parallel to the Y-axis of motion), at a speed of 1200mm / s and a spacing of 40μm to scan parallel lines. Repeat the scan along the same path twice. A scaly structure will appear on the surface of the ceramic green body. Each scaly protrusion is 50μm long, 40μm wide, and 20μm high. This can increase the hydrophilicity of the surface of the green body, which is conducive to the deposition of ceramic particles in the subsequent ink, thereby improving the structural strength.

[0075] To reduce the surface roughness of the printed parts, use an infrared picosecond laser (wavelength 1035nm, frequency 1800kHz) at 40% power and a speed of 1200mm / s to scan the raised areas. Each scan removes 10μm of green material. Repeat the scan until all raised areas are removed.

[0076] To reduce the surface roughness of printed parts

[0077] S6: Repeat S2, S3, S4 and S5, inkjet printing the ceramic component green body 8 layer by layer from bottom to top and making corrections and microstructure engravings until a complete ceramic component green body 8 is obtained.

[0078] S7: Immerse the ceramic component green body 8 obtained in S6 in pure water (conductivity < 20 μS / cm) for 1 hour to remove water-soluble support material, and then let it stand in the air for 3 hours to dry naturally.

[0079] S8: The ceramic component green body 8 obtained in S7 after removing the support is placed in a programmable high-temperature sintering furnace for sintering. The temperature is increased from 25℃ to 250℃ at a heating rate of 4℃ / min, and held at 250℃ for 2 hours. The temperature is then increased to 350℃ at the same heating rate and held for 3 hours. The temperature is then increased to 450℃ at the same heating rate and held for 3 hours. Subsequently, the temperature is increased to 800℃ at a heating rate of 3℃ / min for pre-sintering and held for 3.6 hours. Finally, the temperature is increased to 1450℃ at a heating rate of 3℃ / min for sintering, held for 9 hours, and then cooled to room temperature at a rate of 3℃ / min to obtain the finished ceramic component.

[0080] In this embodiment, for ceramic component green bodies 8 with a volume of less than 0.5 cm³ or a maximum cross-sectional thickness of less than 2 mm, the holding time in each stage of the sintering process can be shortened by 30%, thereby improving work efficiency while ensuring quality. For larger or thicker parts, the heating rate should be appropriately reduced and the holding time extended to ensure component quality.

[0081] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0082] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for layer-by-layer inkjet printing of a ceramic material, characterized in that, The method comprises the following steps: Step 1: printing a first layer of ceramic green body, and heating the layer of ceramic green body to preliminarily shape it; Step 2: scanning the top surface morphology of the ceramic green body after heating, and comparing it with an ideal model; Step 3: correcting the top surface of the ceramic green body and carving microstructures on it according to the comparison result, so that the hydrophilicity and roughness of the ceramic green body are close to the ideal model; The correction comprises, comparing the actual height data of the top surface of the current printing layer with the theoretical height data, recording the difference between them when the actual height is less than the theoretical value, and compensating by increasing the number of printing layers; when the actual height is greater than the theoretical value, presetting laser processing parameters to ablate the top of the green body and remove the excess part of the top of the green body; The microstructure carving comprises, if it is necessary to improve the structural strength of the ceramic member, using an infrared picosecond laser to scan parallel lines perpendicular to the extension direction of the ridges and grooves on the top surface of the green body, so that a scale structure appears on the top surface of the ceramic green body; if it is necessary to reduce the surface roughness of the ceramic member, using an infrared picosecond laser to repeatedly scan the ridge position until the ridge position is completely removed; Step 4: repeating steps 1 to 3, and printing the ceramic member green body from bottom to top until the completed ceramic member green body is obtained; Step 5: removing the water-soluble support material on the surface of the ceramic green body; Step 6: sintering the ceramic green body to obtain a finished ceramic member.

2. The method according to claim 1, wherein In the scale structure, a single scale protrusion has a length of about 50 μm, a width of about 40 μm, and a height of about 20 μm.

3. The method according to claim 1, wherein The step 5 specifically comprises: immersing the ceramic green body in pure water for 1 hour to remove the water-soluble support material, and then naturally drying it in air for 3 hours.

4. An apparatus for implementing the method of claim 1 for the layer-by-layer inkjet printing of ceramic materials, characterized by: The device comprises a mounting frame, a two-dimensional motion platform is arranged on the lower part of the mounting frame in the axial direction thereof, a printing module, a heating lamp module, a detection module and a laser module are sequentially arranged on the upper part of the mounting frame in the axial direction thereof, and an upper computer is arranged for regulating and controlling the two-dimensional motion platform, the printing module, the heating lamp module, the detection module and the laser module.

5. The apparatus of claim 4 wherein, A workbench is arranged on the top of the two-dimensional motion platform, and the workbench comprises a support which is fixedly connected with the two-dimensional motion platform, and a heat insulation layer and a manufacturing substrate are arranged on the top of the support.

6. The apparatus of claim 4 wherein, The printing module comprises a moving Y-axis mounting frame which is fixedly connected with the mounting frame, a moving Y-axis hanging basket which is slidably connected with the moving Y-axis mounting frame is arranged below the moving Y-axis mounting frame, and an inkjet printing head is arranged on the moving Y-axis hanging basket.

7. The apparatus of claim 4 wherein, The heating lamp module comprises a heating lamp mounting frame which is fixedly connected with the mounting frame, and a heating lamp is arranged on the heating lamp mounting frame.

8. The apparatus of claim 4 wherein, The detection module comprises a detection head mounting frame which is fixedly connected with the mounting frame, and a laser triangulation detection head is arranged on the detection head mounting frame, and the laser triangulation detection head is connected with an external signal processing module and the upper computer.

9. The apparatus of claim 4 wherein, The laser module comprises a galvanometer mounting frame which is fixedly connected with the mounting frame, a galvanometer is arranged on the galvanometer mounting frame, and the light inlet hole of the galvanometer is in communication with an external light path, and the galvanometer is connected with an external processing module and the upper computer.

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