Ceramic slurry direct writing forming milling layer-by-layer composite forming method and equipment

Abstract

The invention relates to a ceramic slurry direct writing forming milling processing layer-by-layer composite forming method and device, and the method comprises the steps: dividing a ceramic green body into a plurality of groups from bottom to top, and dividing each group into a plurality of printing layers from bottom to top; each printing layer in each group is printed in sequence from bottom to top, and each printing layer is preliminarily heated and shaped after being printed; after preliminary heating and shaping, scanning the current printing layer, and milling to remove the part, which cannot be in contact with the next printing layer, of the end part of the current printing layer; after each group is printed, scanning the top surface of the current ceramic green body, comparing the top surface of the current ceramic green body with a theoretical value, and correcting the top surface of the current ceramic green body or supplementing the next printing layer according to a comparison result; and the ceramic green body is finally heated and shaped after being integrally printed. The non-contact part between the adjacent printing layers is removed through milling, and only the tightly-contacted part is left, so that the interlayer adhesion performance is improved, the strength of a printed part is improved, and the density of the printed part can be improved.

Description

Technical Field

[0001] The present application relates to the field of additive manufacturing technology, and in particular to a ceramic slurry direct writing molding milling layer-by-layer composite molding method and equipment. Background Art

[0002] Ceramic materials refer to a class of inorganic non-metallic materials that are formed and sintered at high temperatures using natural or compound materials. They have the advantages of high melting point, high hardness, high wear resistance, and oxidation resistance. Therefore, they have received widespread attention from academia and industry, and are widely used in aerospace, medical, electronics and other industries.

[0003] At present, ceramic parts manufactured by slurry direct writing additive manufacturing have certain limitations in terms of precision and density. During the manufacturing process, due to the high viscosity and certain self-support of DIW slurry, the ends of each layer of slurry in the green body will be in a semi-cylindrical shape, and the two sides of each layer of slurry cannot be tightly connected to the adjacent layers, resulting in gaps between layers and reducing the density of the parts. The amount of slurry in each layer cannot be completely accurate. The accumulated error between the amount of slurry in each layer and the standard value will increase the shape error of the upper surface and affect the precision of the ceramic parts.

[0004] Therefore, a composite molding method and equipment that can realize high-precision and high-quality ceramic parts manufacturing is needed. Summary of the invention

[0005] Based on this, it is necessary to provide a ceramic slurry direct writing milling layer-by-layer composite molding method and equipment to overcome the defects mentioned in the above background technology.

[0006] A ceramic slurry direct writing milling layer-by-layer composite molding method comprises the following steps: Step 1: Divide the ceramic green body into multiple groups from bottom to top, and each group is divided into multiple printing layers from bottom to top; Step 2: Print each layer in each group from bottom to top, and heat and fix each layer after printing. Step 3: After preliminary heating and shaping, scan the current printing layer and mill to remove the end of the current printing layer that cannot contact the next printing layer; Step 4: After each group of printing is completed, scan the top surface of the current ceramic green body and compare it with the theoretical value. According to the comparison result, correct the top surface of the current ceramic green body or fill it in the next printing layer; Step 5: After the entire ceramic green body is printed, it is finally heated and shaped.

[0007] As a preferred method for the layer-by-layer composite molding of the ceramic slurry direct writing and milling process in the present invention, in the step 3, scanning the current printing layer and milling to remove the portion of the end of the current printing layer that cannot contact the next printing layer specifically includes: Scan the arc structures at both ends of the current printing layer, preset the milling parameters of the milling cutter according to the scanning results, and mill the arc structures at both ends of the current printing layer to remove the part of the end of the printing layer that cannot contact with the next printing layer, leaving only the part in close contact.

[0008] As a preferred method for the layer-by-layer composite forming of the ceramic slurry direct writing milling process in the present invention, in the step 4, the top surface of the current ceramic green body is corrected or filled in the next printing layer according to the comparison result, which specifically includes: The actual height data of the top surface of the current printing layer is compared with the theoretical height data. When the actual height is less than the theoretical value, the difference between the two is recorded and compensated by increasing the number of printing layers. When the actual height is greater than the theoretical value, the preset milling parameters are used to mill the top of the green body to remove the raised part on the top of the green body.

[0009] A device for realizing the ceramic slurry direct writing molding and milling processing layer-by-layer composite molding method, which includes a mounting frame, a preliminary molding component is provided on one side of the mounting frame, and a milling cutter module is provided on one side of the preliminary molding component. The preliminary molding component is used to print ceramic green bodies layer by layer in groups, and the milling cutter module is used to perform milling correction on each layer and each group of ceramic green bodies.

[0010] As a preferred embodiment of the equipment described in the present invention, the preliminary process forming component includes a slurry direct writing printing module, a heating module and a two-dimensional motion platform, the slurry direct writing printing module is connected to the mounting frame, the heating module is arranged on one side of the slurry direct writing printing module, and the two-dimensional motion platform is arranged below the slurry direct writing printing module, the heating module and the milling cutter module.

[0011] As a preferred embodiment of the device described in the present invention, the slurry direct writing printing module includes a Y-axis bracket and a nozzle assembly, the Y-axis bracket is provided with a driving assembly, the driving assembly is provided with a print head bracket that can slide along the Y-axis direction, and the nozzle assembly is connected to the print head bracket, and its output end is facing the direction of the two-dimensional motion platform.

[0012] As a preferred embodiment of the device of the present invention, the heating module includes a heating lamp, which is connected to the mounting frame via a heating lamp bracket, and the output end of the heating lamp faces the direction of the two-dimensional motion platform.

[0013] As a preferred embodiment of the device described in the present invention, the two-dimensional motion platform includes a motion X-axis extending along the X-axis direction, the motion X-axis is provided with a motion Z-axis extending along the Z-axis direction, the motion Z-axis is slidably connected to the motion X-axis through a connector, and the motion Z-axis is provided with a workbench slidably connected thereto.

[0014] As a preferred embodiment of the device described in the present invention, the workbench includes a workbench bracket, one side of which is slidably connected to the moving Z axis, and the top of which is provided with a heat insulation layer and a printing substrate in sequence from bottom to top.

[0015] As a preferred embodiment of the device described in the present invention, the milling cutter module includes a milling cutter seat, which is connected to the mounting frame through a milling cutter bracket, a milling cutter is arranged in the milling cutter seat, and a milling cutter motor is arranged on one side of the milling cutter seat, and its output end is connected to the milling cutter transmission.

[0016] Beneficial effects of the present invention: 1. The present invention removes the incontact portions between adjacent printed layers by milling, leaving only the closely contacted portions. Thus, when printing the N+1th layer, the extruded slurry can fully contact the Nth layer, thereby improving the interlayer adhesion performance and thus improving the strength of the printed part, and can improve the density of the printed part.

[0017] 2. The present invention scans the top surface of the ceramic green body after printing a certain number of layers, compares the scanning result with the theoretical result, and thus performs milling correction or compensation on the top surface of the current ceramic green body, which can eliminate the layer thickness error accumulated layer by layer during the additive manufacturing process of the ceramic green body, thereby improving its accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a schematic diagram of the overall structure of the device in the embodiment of the present application; Figure 2 This is a schematic diagram of the structure of the slurry direct writing module in the embodiment of the present application; Figure 3 This is a schematic diagram of the structure of the milling cutter module in the embodiment of the present application; Figure 4 This is a working schematic diagram of a printing station in an embodiment of the present application; Figure 5 This is a schematic diagram of the working of the heating station in the embodiment of the present application; Figure 6This is a working schematic diagram of a milling station in an embodiment of the present application; Description of reference numerals: 101, mounting frame; 102, heating lamp bracket; 103, moving X axis; 104, heating lamp; 105, connector; 106, moving Z axis; 107, workbench bracket; 108, thermal insulation layer; 109, printing substrate; 2. Milling cutter module; 201. Milling cutter bracket; 202. Milling cutter seat; 203. Milling cutter motor; 204. Milling cutter; 205. Dust suction port; 3. Slurry direct writing printing module; 301. Y-axis bracket; 302. Y-axis guide rod; 303. Lead screw; 304. Print head buckle; 305. Print nozzle; 306. Slurry storage tank; 307. Print head bracket; 308. Air inlet; 309. Drive motor; 4. Ceramic green body. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0021] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0022] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0023] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0024] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0026] Example This embodiment provides a ceramic slurry direct writing milling layer-by-layer composite molding method, comprising the following steps: The ceramic green body 4 is divided into multiple groups from bottom to top, and each group is divided into multiple printing layers from bottom to top.

[0027] Each group of ceramic green bodies 4 is printed sequentially from bottom to top according to the grouping, and multiple printing layers in each group are printed sequentially from bottom to top. After each printing layer is printed, it is heated to give it a preliminary shape until a complete ceramic green body 4 is formed.

[0028] During the printing process, after each layer is initially shaped, the arc structures at both ends of the current printing layer are scanned using a scanning mechanism, and the milling parameters of the milling cutter module 2 are preset according to the scanning results to mill the arc structures at both ends of the current printing layer, removing the portion of the end of the printing layer that cannot contact the next printing layer, and leaving only the portion that is in close contact, so that when printing the N+1th layer, the extruded slurry can fully contact the Nth layer, thereby improving the interlayer adhesion performance and thus improving the strength of the printed part, and can improve the density of the printed part; When each group of printing is completed, the scanning mechanism is used to scan the top surface of the current ceramic green body 4, and the actual height data of the top surface of the current printing layer is compared with the theoretical height data. When the actual height is less than the theoretical value, the difference between the two is recorded and compensated by increasing the number of printing layers; when the actual height is greater than the theoretical value, the feed speed, milling cutter speed, etc. in the milling processing parameters of the preset milling cutter module 2 are used to mill the top of the ceramic green body 4 to remove the raised part on the top of the green body, thereby achieving the purpose of eliminating the layer thickness error.

[0029] After the ceramic green body 4 is printed as a whole, it is finally heated and shaped.

[0030] This embodiment also provides a device for the above ceramic slurry direct writing molding milling layer-by-layer composite molding method, such as Figure 1 As shown, it comprises a mounting frame 101 , one side of which is provided with a preliminary forming assembly for printing ceramic green bodies 4 in groups and layers, and one side of which is provided with a milling cutter module 2 for milling and correcting each layer and each group of the ceramic green bodies 4 .

[0031] The preliminary process forming component includes a slurry direct writing printing module 3, a heating module and a two-dimensional motion platform. The slurry direct writing printing module 3 and the heating module are connected to the mounting frame 101 and are arranged in sequence along the X-axis direction. The two-dimensional motion platform is arranged below the slurry direct writing printing module 3, the heating module and the milling cutter module 2, and is provided with a workbench that can move along the X-axis and Y-axis directions.

[0032] like Figure 2As shown, the slurry direct writing printing module 3 includes a Y-axis bracket 301 and a nozzle assembly, the Y-axis bracket 301 is provided with a driving assembly, the driving assembly includes a lead screw 303 and a driving motor 309, one end of the lead screw 303 is rotatably connected to the Y-axis bracket 301, and the other end is transmission-connected to the driving motor 309, and the two sides of the lead screw 303 are provided with a Y-axis guide rod 302, and the lead screw 303 is provided with a print head bracket 307 that is screwed and connected thereto, and the two ends of the lead screw 303 are slidably connected to the Y-axis guide rod 302 to limit the position thereof, and the print head bracket 307 can move along the Y-axis direction under the drive of the driving assembly. The nozzle assembly includes a slurry storage tank 306, the output end of which is provided with a printing nozzle 305 facing the direction of the two-dimensional motion platform, and the top of the top is provided with an air inlet 308 for connecting to an air pump; the slurry storage tank 306 is detachably connected to the print head bracket 307 through the print head buckle 304 at the bottom of the print head bracket 307.

[0033] The heating module includes a heating lamp 104 , which is connected to the mounting frame 101 through a heating lamp bracket 102 , and the output end of the heating lamp 104 faces the direction of the two-dimensional motion platform.

[0034] The two-dimensional motion platform includes a motion X-axis 103, which extends along the X-axis direction. The motion X-axis is provided with a motion Z-axis 106 extending along the Z-axis direction. The motion Z-axis 106 is slidably connected to the motion X-axis 103 through a connector 105. The motion X-axis 103 and the motion Z-axis 106 are driven by an external motor to achieve movement in two directions. The workbench is slidably connected to the motion Z-axis 106.

[0035] The workbench includes a workbench bracket 107, one side of which is slidably connected to the moving Z axis 106, and the top of the workbench is provided with a heat insulation layer 108 and a printing substrate 109 from bottom to top. The printing substrate 109 is threadedly connected to the heat insulation layer 108. Holes are left in the printing substrate 109 for installing heating wires and thermocouples. The printing substrate 109 can be heated at a constant temperature to keep the bottom temperature of the ceramic green body 4 constant during the printing process.

[0036] like Figure 3 As shown, the milling cutter module 2 includes a milling cutter seat 202, which is connected to the mounting frame 101 through a milling cutter bracket 201. A milling cutter 204 is arranged in the milling cutter seat 202. A milling cutter motor 203 is arranged on one side of the milling cutter seat 202, and an output end thereof is transmission-connected to the milling cutter 204. A dust suction port 205 is provided above the milling cutter seat 202 for suctioning dust during milling.

[0037] It also includes a detection module for scanning the top surface of the ceramic green body 4.

[0038] The usage of the above equipment is as follows: S1, put the ceramic slurry into the slurry storage tank 306, fix the slurry storage tank 306 on the print head bracket 307 through the print head buckle 304, and connect the air inlet 308 on the top of the slurry storage tank 306 to the air pump.

[0039] S2, such as Figure 4 As shown, the workbench and the printing nozzle 305 are moved to the printing station and positioned at the starting position of printing, the air pump is turned on, and the slurry in the slurry storage tank 306 is pressed out from the printing nozzle 305 by high-pressure gas, and the pressed slurry is deposited on the printing substrate 109. The X-axis of the two-axis motion platform is linked with the Y-axis of the printing module, so that the print head prints according to a preset path to obtain a layered ceramic green body 4; after the ceramic green body 4 of the current printing layer is printed, the air pump stops supplying gas, the pressure in the slurry storage tank 306 returns to normal, and the slurry stops being pressed out.

[0040] S3, such as Figure 5 As shown, after one printing layer is printed, the two-axis motion platform drives the workbench to move to the heating station, and the heating lamp 104 starts to work to evaporate the solvent in the ceramic green body 4, and the current layer of ceramic green body is initially solidified. After the heating is completed, the heating lamp 104 is turned off, and the workbench returns to the printing station.

[0041] S4, repeat S2 and S3 until the number of printing layers of a set is reached.

[0042] S5, such as Figure 6 As shown, after reaching a set of printing layers, the top of the current printing layer is scanned by the detection module. After scanning and comparison, if the actual height is greater than the theoretical height, the two-axis motion platform then drives the workbench to move to the milling station, and the milling parameters are preset according to the scanning results. The milling cutter motor 203 starts working, driving the milling cutter 204 to rotate, and the external dust collection device starts working at the same time, and the generated dust is discharged from the dust collection port 205; the milling cutter 204 mills the top of the ceramic green body 4 on the printing substrate 109 to eliminate the accumulated printing layer thickness error. After milling is completed, the milling cutter motor 203 and the external dust collection device stop working, and the workbench returns to the printing station. If the actual height is less than the theoretical height, the difference between the two is recorded and compensated by increasing the number of printing layers.

[0043] S6, repeating S4 and S5 until the last set of printing and milling is completed to obtain a complete ceramic material green body.

[0044] S7, post-processing of the parts, removing the ceramic green body 4 from the printed substrate 109, drying it at 60°C for 24 hours, placing it in a sintering furnace and gradually heating it to 1400°C for 30 hours to form the ceramic parts.

[0045] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0046] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A ceramic slurry direct writing milling layer-by-layer composite molding method, characterized in that: The steps include: Step 1: Divide the ceramic green body into multiple groups from bottom to top, and each group is divided into multiple printing layers from bottom to top; Step 2: Print each layer in each group from bottom to top, and heat and fix each layer after printing. Step 3: After preliminary heating and shaping, scan the current printing layer and mill to remove the end of the current printing layer that cannot contact the next printing layer; Step 4: After each group of printing is completed, scan the top surface of the current ceramic green body and compare it with the theoretical value. According to the comparison result, correct the top surface of the current ceramic green body or fill it in the next printing layer; Step 5: After the entire ceramic green body is printed, it is finally heated and shaped.

2. According to claim 1, the ceramic slurry direct writing milling layer-by-layer composite molding method is characterized in that: In the step 3, scanning the current printing layer and removing the portion of the end of the current printing layer that cannot contact the next printing layer by milling specifically includes: Scan the arc structures at both ends of the current printing layer, preset the milling parameters of the milling cutter according to the scanning results, and mill the arc structures at both ends of the current printing layer to remove the part of the end of the printing layer that cannot contact with the next printing layer, leaving only the part in close contact.

3. The ceramic slurry direct writing milling layer-by-layer composite molding method according to claim 1, characterized in that: In the step 4, correcting the top surface of the current ceramic green body or filling it in the next printing layer according to the comparison result specifically includes: The actual height data of the top surface of the current printing layer is compared with the theoretical height data. When the actual height is less than the theoretical value, the difference between the two is recorded and compensated by increasing the number of printing layers. When the actual height is greater than the theoretical value, the preset milling parameters are used to mill the top of the green body to remove the raised part on the top of the green body.

4. A device for realizing the ceramic slurry direct writing milling layer-by-layer composite molding method according to claim 1, characterized in that: It comprises a mounting frame, one side of which is provided with a preliminary forming assembly, one side of which is provided with a milling cutter module, the preliminary forming assembly is used for printing ceramic green bodies in groups and layers, and the milling cutter module is used for performing milling correction on each layer and each group of ceramic green bodies.

5. The device according to claim 4, characterized in that: The preliminary process forming component includes a slurry direct writing printing module, a heating module and a two-dimensional motion platform. The slurry direct writing printing module is connected to the mounting frame, the heating module is arranged on one side of the slurry direct writing printing module, and the two-dimensional motion platform is arranged below the slurry direct writing printing module, the heating module and the milling cutter module.

6. The device according to claim 5, characterized in that: The slurry direct writing printing module includes a Y-axis bracket and a nozzle assembly, the Y-axis bracket is provided with a driving assembly, the driving assembly is provided with a print head bracket that can slide along the Y-axis direction, the nozzle assembly is connected to the print head bracket, and its output end faces the direction of the two-dimensional motion platform.

7. The device according to claim 5, characterized in that: The heating module comprises a heating lamp, which is connected to the mounting frame via a heating lamp bracket, and the output end of the heating lamp faces the direction of the two-dimensional motion platform.

8. The device according to claim 5, characterized in that: The two-dimensional motion platform includes a motion X-axis extending along the X-axis direction. The motion X-axis is provided with a motion Z-axis extending along the Z-axis direction. The motion Z-axis is slidably connected to the motion X-axis through a connector. The motion Z-axis is provided with a workbench slidably connected thereto.

9. The device according to claim 8, characterized in that: The workbench comprises a workbench bracket, one side of which is slidably connected to the moving Z axis, and the top of which is provided with a heat insulation layer and a printing substrate in sequence from bottom to top.

10. The device according to claim 4, characterized in that: The milling cutter module comprises a milling cutter seat, which is connected to a mounting frame via a milling cutter bracket. A milling cutter is arranged in the milling cutter seat. A milling cutter motor is arranged on one side of the milling cutter seat, and an output end of the motor is transmission-connected to the milling cutter.

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