A ceramic multi-material continuous forming light solidification additive manufacturing apparatus

Abstract

The application relates to a ceramic multi-material continuous forming light-curing additive manufacturing equipment and a process control method thereof. The application is applied to additive manufacturing of multi-material heterogeneous and complex-shaped ceramic components. The ceramic multi-material continuous forming light-curing additive manufacturing equipment comprises a vibration isolation table, a release film conveying module, a multi-material feeding module, a substrate rotating module and a DLP light machine projection displacement module, and each module is installed on the upper surface of the vibration isolation table; the vibration isolation table is a mounting base of the whole equipment and is used for reducing the influence of external vibration on printing precision; the release film conveying module is used for conveying paste and residual paste after curing; the multi-material feeding module is used for feeding different ceramic pastes and realizing material feeding switching; the substrate rotating module is used for bonding and curing ceramic blanks, realizing multi-layer printing and substrate cleaning during material replacement; and the DLP light machine projection displacement module is used for projecting slice patterns to cure the paste and realizing large-format splicing forming.

Description

Technical Field

[0001] This invention relates to a photopolymer additive manufacturing equipment for continuous forming of multi-material ceramics and its process control method. It is applied to the additive manufacturing of multi-material heterogeneous and complex irregular-shaped ceramic components. Background Technology

[0002] Advanced complex ceramic components are a crucial foundation for supporting the development of my country's next-generation strategic emerging industries such as biomedicine and aerospace. Additive manufacturing is a revolutionary technology for forming complex ceramic components. The operating environments in fields such as biomedicine and aerospace are complex, with stringent functional requirements, placing extremely high demands on the composition, structure, and performance of different parts of ceramic components. For example, craniomaxillary implants require coupled biocompatible functional structures such as high-strength imitation cortical bone and porous, biodegradable imitation cancellous bone; rocket engine thrust chambers require coupled functional structures such as high-strength, high-precision atomizing nozzles, gradient mixing combustion chambers, and high-temperature resistant nozzles. The demand for multi-material complex ceramic components is urgent.

[0003] However, existing multi-material photopolymer additive manufacturing equipment suffers from problems such as easy mixing of multiple materials, small printing area, and low material changeover printing efficiency. Specifically, traditional multi-material photopolymer additive manufacturing equipment generally uses a variable-volume material tank or multiple material tank switching to achieve multi-material material changeover. This easily leads to material waste and material mixing and cross-contamination during the material changeover process. Moreover, this method is only suitable for slurries and is no longer applicable to pastes with poor flowability. Existing multi-material photopolymer additive manufacturing equipment mostly uses a single-photometer fixed light source for curing and forming, which makes it difficult to simultaneously meet the requirements of high precision and large format; especially when printing high-precision, large-format samples or batch printing of multiple high-precision samples, it is difficult to meet the needs. Another material changeover method is coating-based material changeover, where the material to be cured is first coated at the bottom of the material tank. When material changeover is needed, the bottom of the material tank is cleaned before applying another material. However, these steps need to be performed one by one, and the cleaning process is quite time-consuming. When frequent material changeovers are required, this greatly affects the material changeover printing efficiency. These equipment defects limit the application potential of multi-material ceramic components.

[0004] Therefore, addressing equipment defects and achieving efficient and high-precision forming of multi-material, heterogeneous, and complex irregular-shaped ceramic components is crucial for promoting the disruptive application of advanced ceramic components in the fields of biomedicine and aerospace. Summary of the Invention

[0005] The purpose of this invention is to solve the above-mentioned problems and provide a ceramic multi-material continuous forming photopolymer additive manufacturing equipment. Its advantages include: using a feed head to coat the material onto the release film, avoiding mixing and cross-contamination of multiple materials; employing a small-pixel-size optical engine to ensure forming accuracy; and using a moving single-light source static splicing method to achieve large-format forming, thus balancing the needs of high precision and large format. The use of a release film conveyor for material changing allows for simultaneous release film cleaning and photopolymer forming. When material changing is needed, the corresponding material can be directly supplied without waiting for release film cleaning, improving material changing and printing efficiency.

[0006] A ceramic multi-material continuous forming photopolymer additive manufacturing equipment includes a vibration isolation table, a release film conveying module, a multi-material feeding module, a substrate rotation module, and a DLP optomechanical projection displacement module. Each module is mounted on the upper surface of the vibration isolation table. The vibration isolation table serves as the mounting base for the entire equipment, reducing the impact of external vibrations on printing accuracy. The release film conveying module transports the paste and any remaining cured paste. The multi-material feeding module supplies different ceramic pastes and enables material switching. The substrate rotation module bonds and cures the ceramic preform, enables multi-layer printing, and facilitates substrate cleaning during material changes. The DLP optomechanical projection displacement module projects sliced ​​patterns of cured paste and enables large-format splicing and forming.

[0007] The release film of the release film conveying module is an oxygen-permeable photocurable release film. The release film is supported by an external roller to form a cycle and is driven by an external stepper motor to make a cycle. The oxygen-permeable photocurable release film allows oxygen to pass through to inhibit the photocuring reaction and forms an uncured dead zone above the release film.

[0008] The oxygen-permeable photocurable release film is made of PDMS material. It has good air permeability, allowing oxygen to pass through and inhibiting the photocuring reaction, thereby forming an uncured dead zone above the release film. This prevents the printed preform from sticking to the release film, ensuring continuous forming, saving release time, and reducing the step effect between layers.

[0009] The multi-material feeding module includes three feeding heads and a C-axis displacement module. Each feeding head corresponds to a material. The feeding head is responsible for supplying ceramic paste. By controlling the opening and closing of the feeding heads and using the C-axis displacement module to switch the feeding head directly above the release film, the material supply can be switched.

[0010] The substrate rotation module includes a substrate, a Z-axis displacement module, and a D-axis rotary table. The substrate is responsible for bonding the cured ceramic blank. The Z-axis displacement module drives the substrate to move up and down to achieve multi-layer printing. The D-axis rotary table drives the substrate to rotate 180 degrees, which is used to place the substrate into an external ultrasonic cleaner to clean the paste residue when changing materials.

[0011] The DLP optical engine projection displacement module includes a DLP optical engine and an XY displacement stage. The XY displacement stage includes an X-axis displacement module and a Y-axis displacement module. The DLP optical engine is responsible for projecting the sliced ​​pattern of the printed part and irradiating the cured ceramic paste through the release film. The XY displacement stage carries the DLP optical engine to move in the XY direction, realizing the large-format splicing and forming of the projection. The DLP optical engine is a small pixel size optical engine to ensure forming accuracy.

[0012] A process control method based on the aforementioned ceramic multi-material continuous forming photopolymer additive manufacturing equipment includes a pre-processing process for the printed part model and a printing process. The printing process includes five steps: multi-material feeding, photopolymer forming, paste recovery, release film cleaning and drying, and printed blank cleaning. The paste recovery, release film cleaning and drying, and printed blank cleaning processes are implemented by existing external equipment.

[0013] The specific steps of the preprocessing process for the printed model are as follows: The STL format 3D model of the printed part is sliced ​​into layer-by-layer image formats using commercial slicing software; single-layer images are divided according to the DLP optical engine projection area and sorted according to the projection order using a Python program to obtain the image set required for the DLP optical engine projection; G-code instructions corresponding to the equipment execution actions are written according to the single-layer printing process plan; the material change timing and actions between or within layers are planned according to the material distribution of the multi-material printed part; based on the conditions of each layer and the material change plan, the single-layer printing G-code instructions are integrated to complete the instruction configuration for multi-layer, multi-material printing, and the preprocessed image set and the full-process G-code instructions are obtained.

[0014] The commercial slicing software is Autodesk Netfabb Standard; after printing begins, the preprocessed image set and G-code instructions are sent to the equipment control system, and the equipment executes a single-layer printing cycle to complete multi-layer ceramic printing. The specific process of single-layer printing is as follows:

[0015] Step 1: The feeding head supplies ceramic paste onto the release film until the feeding area is fully coated. Material switching is achieved by switching the feeding head through the C-axis displacement module as needed.

[0016] Step 2: The release film delivery module delivers the paste to the photocuring area. The substrate descends to a height one layer thick from the release film. The DLP optical engine projects the sliced ​​pattern to cure the paste and adhere it to the substrate. The XY displacement stage drives the DLP optical engine to move and realize the projection splicing, completing the curing of the pattern layer.

[0017] Step 3: The Z-axis displacement module lifts the base to maintain a distance between the blank and the release film. The release film conveying module sends the remaining paste to the residual material recovery area of ​​the external paste recovery module, where the residual material is recovered by the negative pressure suction head of the industrial vacuum cleaner.

[0018] Step 4: The release film conveying module sends the release film with residual paste to the external ultrasonic cleaner for cleaning. After being initially dried by an absorbent sponge, it is further dried by the external fan system.

[0019] Step 5: If no material change is needed, proceed directly to the next layer of printing; if a material change is required, first perform the printing blank cleaning process, then switch materials and prepare for the next layer of printing.

[0020] The specific operation of the printing blank cleaning process is as follows: the D-axis rotary table drives the substrate to rotate 180 degrees, and the substrate is placed into an external ultrasonic cleaner to clean the residue of the paste. After cleaning, the D-axis rotary table rotates the substrate back to its original position, and the multi-material feeding module switches the corresponding feeding head. The cleaning and drying process of the release film is carried out simultaneously with the photocuring process. When changing materials, the corresponding material is supplied directly without waiting for the release film to be cleaned.

[0021] The beneficial effects of the ceramic multi-material continuous forming photopolymer additive manufacturing equipment of the present invention are:

[0022] The material is supplied by coating the release film with a feed head, which avoids mixing and cross-contamination of multiple materials;

[0023] Small-pixel-size optical engines are selected to ensure forming accuracy, and a moving single-light source static splicing method is used to achieve large-format forming, which can meet the needs of both high precision and large format.

[0024] By using a release film conveyor for material changing, the release film cleaning and photocuring can be carried out simultaneously. When a material change is needed, the corresponding material can be supplied directly without waiting for the release film to be cleaned, thus improving the efficiency of material changing and printing. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific implementation methods.

[0026] Figure 1 A schematic diagram of a photopolymer additive manufacturing equipment for continuous forming of multiple ceramic materials;

[0027] Figure 2 This is a schematic diagram of a DLP optical engine projection displacement module;

[0028] Figure 3 Flowchart for preprocessing printed models;

[0029] Figure 4 This is a flowchart for the control process of a single-layer printing operation.

[0030] In the picture:

[0031] Vibration isolation table 11;

[0032] Release film delivery module 12;

[0033] Multi-material feeding module 13; feeding head 131; C-axis displacement module 132;

[0034] Base rotation module 14; Base 141; Z-axis displacement module 142; D-axis rotary table 143;

[0035] DLP optical engine projection shift module 15;

[0036] DLP optical engine 21; XY displacement stage 22; X-axis displacement module 221; Y-axis displacement module 222;

[0037] Material supply area a; UV curing area b; waste material recycling area c. Detailed Implementation

[0038] like Figure 1-2 As shown, a ceramic multi-material continuous forming photopolymer additive manufacturing equipment includes a vibration isolation table 11, a release film conveying module 12, a multi-material feeding module 13, a substrate rotation module 14, and a DLP optomechanical projection displacement module 15. Each module is mounted on the upper surface of the vibration isolation table 11. The vibration isolation table 11 serves as the mounting base for the entire equipment, reducing the impact of external vibrations on printing accuracy. The release film conveying module 12 is used to transport paste and cured paste residue. The multi-material feeding module 13 is used to supply different ceramic pastes and switch between materials. The substrate rotation module 14 is used to bond and cure ceramic blanks, achieve multi-layer printing, and clean the substrate during material changes. The DLP optomechanical projection displacement module 15 is used to project slice patterns of cured paste and achieve large-format splicing forming.

[0039] The release film of the release film conveying module 12 is an oxygen-permeable photocurable release film. The release film is supported by an external roller to form a cycle and is driven by an external stepper motor to perform a cycle motion. The oxygen-permeable photocurable release film allows oxygen to pass through to inhibit the photocuring reaction and forms an uncured dead zone above the release film.

[0040] The oxygen-permeable photocurable release film is made of PDMS material. It has good air permeability, allowing oxygen to pass through and inhibiting the photocuring reaction, thereby forming an uncured dead zone above the release film. This prevents the printed preform from sticking to the release film, ensuring continuous forming, saving release time, and reducing the step effect between layers.

[0041] The multi-material feeding module 13 includes three feeding heads 131 and a C-axis displacement module 132. Each feeding head 131 corresponds to a material. The feeding head 131 is responsible for supplying ceramic paste. By controlling the opening and closing of the feeding head 131 and using the C-axis displacement module 132 to switch the feeding head 131 directly above the release film, the material supply can be switched.

[0042] The substrate rotation module 14 includes a substrate 141, a Z-axis displacement module 142, and a D-axis rotary table 143. The substrate 141 is responsible for bonding the cured ceramic blank. The Z-axis displacement module 142 drives the substrate 141 to move up and down to achieve multi-layer printing. The D-axis rotary table 143 drives the substrate 141 to rotate 180 degrees, which is used to place the substrate 141 into an external ultrasonic cleaner to clean the paste residue when changing materials.

[0043] The DLP optical engine projection displacement module 15 includes a DLP optical engine 21 and an XY displacement stage 22. The XY displacement stage 22 includes an X-axis displacement module 221 and a Y-axis displacement module 222. The DLP optical engine 21 is responsible for projecting the sliced ​​pattern of the printed part and irradiating the cured ceramic paste through the release film. The XY displacement stage 22 carries the DLP optical engine 21 to move in the XY direction, realizing the large-format splicing and forming of the projection. The DLP optical engine 21 is a small pixel size optical engine to ensure forming accuracy.

[0044] A process control method based on the aforementioned ceramic multi-material continuous forming photopolymer additive manufacturing equipment includes a pre-processing process for the printed part model and a printing process. The printing process includes five steps: multi-material feeding, photopolymer forming, paste recovery, release film cleaning and drying, and printed blank cleaning. The paste recovery, release film cleaning and drying, and printed blank cleaning processes are implemented by existing external equipment, and specific details are not shown here.

[0045] Before printing begins, the 3D model of the multi-material print needs to be preprocessed, such as... Figure 3 As shown. First, the STL format 3D model of the printed part is sliced ​​into layer-by-layer image format using commercial slicing software such as Autodesk Netfabb Standard 2019. Since the single-layer printed part is larger than the projection area of ​​the DLP optical engine 21, it needs to be stitched together. Therefore, the single-layer images need to be divided according to the projection area of ​​the DLP optical engine 21 and sorted according to the projection order to obtain the image set required by the DLP optical engine 21. This step can be implemented using a self-written Python program. Then, according to the process plan of single-layer printing, the corresponding G-code instructions are written according to the actions required by the equipment. According to the material distribution of multi-material printed parts, the material change timing and actions between or within layers are planned. According to the situation of each layer and the material change plan, the G-code instructions of single-layer printing are integrated into multi-layer multi-material printing, thereby completing the preprocessing of the printed part model. Through the model preprocessing process, the image set required by the DLP optical engine 21 for projection during the sample printing process is obtained, and the G-code instructions corresponding to all the actions required by the equipment during the printing process are specified.

[0046] After printing begins, the pre-processed image set and G-code instructions are sent to the equipment control system, and the equipment starts printing. The process planning flowchart for single-layer printing is as follows: Figure 4As shown. The entire workflow of the equipment mainly includes the following steps:

[0047] 1. Ceramic paste is supplied to the release film by the feed head 131 in the multi-material feeding module 13 until the entire feeding area a is covered. The material supply can be switched by controlling the opening and closing of the feed head 131 and using the C-axis displacement module 132 to switch the feed head 131 directly above the release film, and the corresponding ceramic paste is supplied as needed.

[0048] 2. The release film delivery module 12 transports the supplied ceramic paste to the area directly above the DLP optical engine 21 projection, i.e., the photocuring area b; the forming substrate 141 descends to a height one layer thick from the release film, and the DLP optical engine 21 projects the corresponding model slice pattern of this layer to cure the ceramic paste and adhere it to the substrate 141; the XY displacement stage 22 carries the DLP optical engine 21 to move to the next projection position, and the DLP optical engine 21 performs projection curing at this position to achieve splicing and forming until the pattern of the spliced ​​and formed printed part on this layer is cured.

[0049] 3. The Z-axis displacement module 142 lifts the substrate 141, maintaining a certain distance between the ceramic blank and the release film. The release film conveying module 12 then transports the remaining ceramic paste to the corresponding residual material recovery area c of the external paste recovery module. The industrial vacuum cleaner of the paste recovery module starts working, using a negative pressure suction head to recover the remaining ceramic paste.

[0050] 4. After recycling, some residual paste remains on the release film. The release film conveying module 12 places the release film with residual paste onto the ultrasonic cleaner of the external release film cleaning module. The ultrasonic cleaner starts working and washes away the paste residue on the release film. The release film is then conveyed to an absorbent sponge for initial drying. Afterward, the external fan system starts working, and as the release film passes through the fan system, the fan will further dry the release film.

[0051] 5. This process is repeated to complete multi-layer ceramic printing. When it is necessary to switch materials, the multi-material feeding module 13 needs to switch to the corresponding material; the forming substrate 141 needs to be rotated 180 degrees by the D-axis rotary table 143 and placed in an external ultrasonic cleaner to clean the residual paste on the ceramic substrate, and then rotated back to print the next layer, thereby avoiding cross-contamination of multiple materials from affecting the forming accuracy.

Claims

1. A ceramic multi-material continuous forming photopolymer additive manufacturing equipment, characterized in that, The system includes a vibration isolation table (11), a release film conveying module (12), a multi-material feeding module (13), a substrate rotation module (14), and a DLP optical engine projection displacement module (15). Each module is installed on the upper surface of the vibration isolation table (11). The vibration isolation table (11) serves as the mounting base for the entire equipment and is used to reduce the impact of external vibrations on printing accuracy. The release film conveying module (12) is used to convey paste and residual paste after curing. The multi-material feeding module (13) is used to supply different ceramic pastes and realize material supply switching. The substrate rotation module (14) is used to bond and cure ceramic blanks, realize multi-layer printing, and clean the substrate during material changes. The DLP optical engine projection displacement module (15) is used to project slice patterns, cure paste, and realize large-format splicing.

2. The ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to claim 1, characterized in that, The release film of the release film conveying module (12) is an oxygen-permeable photocurable release film. The release film is supported by an external roller to form a cycle and is driven by an external stepper motor to make a cycle. The oxygen-permeable photocurable release film allows oxygen to pass through to inhibit the photocuring reaction and forms an uncured dead zone above the release film.

3. The ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to claim 2, characterized in that, The oxygen-permeable photocurable release film is made of PDMS material.

4. The ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to claim 1, characterized in that, The multi-material feeding module (13) includes three feeding heads (131) and a C-axis displacement module (132). Each feeding head (131) corresponds to a material. The feeding head (131) is responsible for supplying ceramic paste. By controlling the opening and closing of the feeding head (131) and using the C-axis displacement module (132) to switch the feeding head (131) directly above the release film, the material supply can be switched.

5. The ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to claim 1, characterized in that, The substrate rotation module (14) includes a substrate (141), a Z-axis displacement module (142), and a D-axis rotary table (143). The substrate (141) is responsible for bonding the cured ceramic blank. The Z-axis displacement module (142) drives the substrate (141) to move up and down to achieve multi-layer printing. The D-axis rotary table (143) drives the substrate (141) to rotate 180 degrees, which is used to place the substrate (141) into an external ultrasonic cleaner to clean the paste residue when changing materials.

6. The ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to claim 1, characterized in that, The DLP optical engine projection displacement module (15) includes a DLP optical engine (21) and an XY displacement stage (22). The XY displacement stage (22) includes an X-axis displacement module (221) and a Y-axis displacement module (222). The DLP optical engine (21) is responsible for projecting the slice pattern of the printed part and irradiating the cured ceramic paste through the release film. The XY displacement stage (22) carries the DLP optical engine (21) to move in the XY direction, so as to realize the large-format splicing of the projection. The DLP optical engine (21) is a small pixel size optical engine to ensure the forming accuracy.

7. A process control method based on the ceramic multi-material continuous forming photopolymer additive manufacturing equipment according to any one of claims 1-6, characterized in that, It includes a pre-processing process for the printed model and a printing process. The printing process includes five steps: multi-material feeding, photopolymerization, paste recovery, release film cleaning and drying, and printed blank cleaning. The paste recovery, release film cleaning and drying, and printed blank cleaning processes are implemented by external existing equipment.

8. The process control method according to claim 7, characterized in that, The specific steps of the preprocessing process for the printed model are as follows: the STL format three-dimensional model of the printed part is cut into layer-by-layer image format using commercial slicing software; the single-layer image is divided according to the projection area of ​​the DLP optical engine (21) and sorted according to the projection order using a Python program to obtain the image set required by the DLP optical engine (21); and the G-code instructions corresponding to the equipment execution actions are written according to the process planning of single-layer printing. Based on the material distribution of multi-material printed parts, plan the timing and actions for material changes between or within layers; based on the conditions of each layer and the material change plan, integrate single-layer printing G-code instructions to complete the instruction configuration for multi-layer, multi-material printing, and obtain the projection image set and the full-process G-code instructions after preprocessing.

9. The process control method according to claim 8, characterized in that, The commercial slicing software is Autodesk Netfabb Standard 2019; after printing begins, the preprocessed image set and G-code instructions are sent to the equipment control system, and the equipment executes a single-layer printing cycle to complete multi-layer ceramic printing. The specific process of single-layer printing is as follows: Step 1: The feed head (131) supplies ceramic paste onto the release film until the feed area (a) is fully coated. The feed head (131) is switched as needed via the C-axis displacement module (132) to achieve material switching. Step 2: The release film delivery module (12) delivers the paste to the photocuring area (b). The substrate (141) descends to a height one layer thick from the release film. The DLP optical engine (21) projects the slice pattern to cure the paste and adheres it to the substrate (141). The XY displacement stage (22) drives the DLP optical engine (21) to move to achieve projection splicing and complete the curing of the pattern layer. Step 3: The Z-axis displacement module (142) lifts the base (141) to keep the blank and the release film at a distance. The release film conveying module (12) sends the remaining paste to the residual material recycling area (c) of the external paste recycling module, and the residual material is recycled by the negative pressure suction head of the industrial vacuum cleaner. Step 4: The release film transfer module (12) sends the release film with residual paste to the external ultrasonic cleaner for cleaning. After being initially dried by the water-absorbing sponge, it is further dried by the external fan system. Step 5: If no material change is needed, proceed directly to the next layer of printing; if a material change is required, first perform the printing blank cleaning process, then switch materials and prepare for the next layer of printing.

10. The process control method according to claim 9, characterized in that, The specific operation of the printing blank cleaning process is as follows: the D-axis rotary table (143) drives the substrate (141) to rotate 180 degrees, and the substrate (141) is placed into an external ultrasonic cleaner to clean the residue of the paste. After cleaning, the D-axis rotary table (143) rotates the substrate (141) back to its original position, and the multi-material feeding module (13) switches the corresponding feeding head (131). The cleaning and drying process of the release film is carried out simultaneously with the photocuring process. When changing materials, the corresponding material is supplied directly without waiting for the release film to be cleaned.

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