A hybrid additive manufacturing splicing method combining SLA and DLP processes

Abstract

The present invention relates to the field of additive manufacturing, and more specifically to an SLA and DLP hybrid process additive manufacturing splicing method, comprising the following steps: S1: reading a test slice image and performing power modulation on a DLP optical projection system and an SLA galvanometer scanning system; S2: judging whether the curing depths of the DLP optical projection system and the SLA galvanometer scanning system are consistent, and adjusting the powers of the DLP optical projection system and the SLA galvanometer scanning system; S3: dividing a DLP projection working area and an SLA scanning working area; S4: calculating, based on the DLP projection working area and the SLA scanning working area, a DLP projection splicing overlap area and a DLP and SLA curing boundary splicing overlap area; S5: planning a DLP and SLA hybrid process forming path based on the DLP projection working area, the SLA scanning working area, the DLP projection splicing overlap area, and the DLP and SLA curing boundary splicing overlap area; and S6: the DLP optical projection system projects according to the process forming path, and the SLA galvanometer scanning system scans according to the process forming path.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing, and more specifically to a method for splicing additive manufacturing processes that combine SLA and DLP. Background Technology

[0002] Photopolymerization is an important category of additive manufacturing technology, characterized by its high precision. Its principle involves using ultraviolet light to irradiate liquid photosensitive resin, causing a photopolymerization reaction that solidifies the resin, which is then layered to form a three-dimensional model. Currently, mature photopolymerization 3D printing technologies can be mainly divided into two types: stereolithography (SLA) rapid prototyping technology and surface-based photopolymerization (DLP) 3D printing technology. The difference lies in the method used to solidify the photosensitive resin: SLA uses a laser scanning method, while DLP uses a projection solidification method based on image mask technology. SLA offers higher precision and resolution but lower forming efficiency; DLP has a larger forming area and higher photopolymerization efficiency. For multi-scale additive manufacturing applications requiring high precision, it is difficult to balance precision and solidification efficiency using a single technology. To overcome these shortcomings, the development of hybrid SLA and DLP technologies has become a research hotspot. The current hybrid SLA and DLP process mainly uses DLP projection to complete large-format photopolymerization molding, while SLA laser scanning forms a higher precision boundary. However, due to the limitation of its working area, the above solution cannot cure large-format materials. In addition, the photopolymerization scale and shape of SLA and DLP are quite different, resulting in poor surface precision. Summary of the Invention

[0003] The purpose of this invention is to provide a splicing method for additive manufacturing using a hybrid SLA and DLP process, which can solve the problems of limited working area and poor surface accuracy during splicing in the hybrid DLP and SLA process.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A hybrid additive manufacturing splicing method combining SLA and DLP processes, comprising the following steps:

[0006] S1: Read the test slice image and perform power modulation on the DLP optical engine projection system and SLA galvanometer scanning system;

[0007] S2: Determine whether the curing depths of the DLP optical engine projection system and the SLA galvanometer scanning system are consistent, and adjust the power of the DLP optical engine projection system and the SLA galvanometer scanning system accordingly;

[0008] S3: Import the 3D model, obtain the 2D slice image of the 3D model, and divide the DLP projection working area and SLA scanning working area.

[0009] S4: Based on the DLP projection working area and the SLA scanning working area, calculate the DLP projection splicing overlap area and the DLP and SLA curing boundary splicing overlap area respectively.

[0010] S5: Based on the DLP projection working area, SLA scanning working area, DLP projection splicing overlap area, and DLP and SLA curing boundary splicing overlap area, plan the molding path of the DLP and SLA hybrid process;

[0011] S6: The DLP optical engine projection system projects according to the process forming path, and the SLA galvanometer scanning system scans according to the process forming path.

[0012] The projection pixel size of the DLP optical engine projection system is 78μm×78μm; the spot diameter of the laser galvanometer in the SLA galvanometer scanning system is 10μm.

[0013] In S1, the energy distribution of the laser spot of the projection of the DLP optical-mechanical projection system and the laser spot of the SLA galvanometer scanning system both follow a Gaussian distribution.

[0014] In step S2, the curing depth of the DLP optical-mechanical projection system and the SLA galvanometer scanning system are compared using an electron microscope to determine whether the power of the DLP optical-mechanical projection system and the SLA galvanometer scanning system should be adjusted.

[0015] In S3, the DLP projection working area and the SLA scanning working area are divided according to the scale of the printed features in the two-dimensional slice image. The DLP optical engine projection system is responsible for large-scale feature shaping, and the SLA galvanometer scanning system is responsible for high-precision feature shaping.

[0016] In step S4, grayscale modulation is performed on the overlapping areas of DLP projection splicing and the overlapping areas of DLP and SLA solidified boundary splicing to eliminate gaps generated during the splicing process.

[0017] In S5, a global path planning algorithm is used to consider the constraints of the DLP projection working area, the SLA scanning working area, the DLP projection splicing overlap area, and the pixel of the DLP and SLA curing boundary splicing overlap area, to obtain the path planning for the DLP and SLA hybrid process forming.

[0018] In step S6, the gantry displacement system drives the DLP optical engine projection system and the SLA galvanometer scanning system to move synchronously. The DLP optical engine projection system projects and cures the photosensitive resin. At the same time, based on the working area of ​​the DLP projection system, the working area of ​​the SLA scanning system, the working area of ​​the DLP optical engine projection system, and the working area of ​​the SLA galvanometer scanning system, it is determined whether to simultaneously perform laser scanning and curing of the SLA galvanometer scanning system. Laser scanning and curing of the SLA galvanometer scanning system is then performed based on the working area of ​​the SLA scanning system.

[0019] A hybrid process photopolymerization molding system includes a gantry displacement system, on which a DLP optomechanical projection system and an SLA galvanometer scanning system are installed. The DLP optomechanical projection system is responsible for large-scale feature molding, and the SLA galvanometer scanning system is responsible for high-precision feature molding.

[0020] The beneficial effects of this invention are as follows:

[0021] The SLA and DLP photopolymerization hybrid process splicing method provided by this invention, on the one hand, expands the working range of the hybrid process by driving the SLA galvanometer scanning system and the DLP optomechanical projection system through the gantry displacement system; on the other hand, the method based on overlapping pixel grayscale modulation ensures the splicing quality and accuracy of DLP projection dynamic splicing and SLA and DLP hybrid process splicing, meeting the requirements of cross-scale and high-precision hybrid process splicing. Attached Figure Description

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0023] Figure 1 This is a schematic diagram of the additive manufacturing splicing method of the SLA and DLP hybrid process of the present invention;

[0024] Figure 2 This is a schematic diagram of the test slice image of the present invention;

[0025] Figure 3 This is a schematic diagram of the DLP optomechanical power modulation process of the present invention;

[0026] Figure 4 This is a schematic diagram of the SLA laser power modulation process of the present invention;

[0027] Figure 5 This is a schematic diagram of a two-dimensional slice image of the present invention;

[0028] Figure 6 This is a schematic diagram of the hybrid process photocuring molding system of the present invention;

[0029] Figure 7 This is a schematic diagram of the hybrid process photocuring molding system of the present invention.

[0030] In the diagram: DLP test projection area 1; SLA test scanning area 2; DLP projection working area 3; SLA scanning working area 4; DLP and SLA hybrid process forming area 5; DLP and SLA hybrid process splicing area 6; gantry displacement system 7; DLP optical engine projection system 8; SLA galvanometer scanning system 9. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings.

[0032] like Figures 1 to 7 As shown, in order to solve the technical problem of "the limitation of working area and poor surface accuracy of the forming surface during the splicing process of DLP and SLA hybrid process", the steps and functions of an additive manufacturing splicing method of SLA and DLP hybrid process are described in detail below;

[0033] like Figure 1 As shown, an additive manufacturing splicing method using a hybrid SLA and DLP process includes the following steps:

[0034] Step S1: Read as follows Figure 2 The test slice image shown illustrates power modulation applied to the DLP optomechanical projection system 8 and the SLA galvanometer scanning system 9. Since the energy distribution of a single pixel projection in the DLP optomechanical projection system 8 and the laser spot in the SLA galvanometer scanning system 9 both follow a Gaussian distribution, power modulation is applied to both. This ensures a uniform light intensity distribution across the entire projection area and, by obtaining the relationship between laser power and curing depth, makes the curing depth of both systems consistent. Figure 3 As shown, the test image is divided into blocks, each image block is projected, and the optical power value of each image block is measured using an optical power meter. Then, the power of the optomechanical projection is corrected according to the calculated power correction coefficient matrix to ensure that the light intensity of the entire projection area is basically consistent, thereby achieving the same curing depth. Figure 4 As shown, the coordinates in the test slice image are calculated to obtain the angle and speed values ​​of the laser galvanometer scan. The power is modulated based on PWM wave modulation technology. By testing the curing depth, the correspondence between the power magnitude and the curing depth is obtained, providing guidance for subsequent mixing process splicing.

[0035] Step S2: By determining whether the curing depths of the two are consistent, the power of both is adjusted accordingly. After the sample corresponding to the slice image in Step 1 is printed, the curing depth is compared under an electron microscope to determine whether further power modulation is needed. By modulating the power of both, the consistent curing depth of SLA laser scanning molding and DLP projection molding is ensured, which is of great significance for ensuring the splicing accuracy in the Z direction.

[0036] Step S3: Import the 3D model and use the software to obtain the following... Figure 4 The two-dimensional slice image shown is divided into a DLP projection working area 3 and an SLA scanning working area 4, with the scale of the printed features in the slice serving as the dividing standard. The DLP optical-mechanical projection system 8 is responsible for forming larger-scale features, while the SLA galvanometer scanning system 9 is responsible for forming higher-precision features. By dividing the working areas into different forming methods, the high-precision forming of the SLA small-diameter spot and the efficient forming of the DLP large-format projection are fully utilized, achieving the cross-scale forming process requirements of large format and high precision. The spot diameter of the laser galvanometer in the SLA galvanometer scanning system 9 is 10 μm; the projection pixel size of the DLP optical-mechanical projection system 8 is 78 μm × 78 μm.

[0037] Step S4: Based on the DLP projection working area 3 and SLA scanning working area 4 defined in Step S3, calculate the DLP projection splicing overlap area and the DLP and SLA curing boundary splicing overlap area respectively. Perform grayscale modulation on the splicing overlap area to eliminate gaps generated during the splicing process. The process includes moving splicing of DLP optical-mechanical projection and splicing of DLP optical-mechanical projection and SLA laser scanning. In Step S3, for the DLP projection working area 3 in the two-dimensional slice, perform grayscale processing on the pixels at the DLP projection boundary. The pixels that have undergone grayscale processing overlap during the splicing process. This reduces the splicing gaps caused by the shrinkage rate during photosensitive resin curing and also reduces overexposure of the photosensitive resin due to unmodulated grayscale overlap images, thus avoiding poor splicing quality. For the stitching of DLP projection and SLA laser spots, since the energy distribution of the laser spot still follows a Gaussian distribution, and the spot diameter is smaller than the pixel size of the DLP projection, the laser scanning boundary is offset towards the DLP projection pixel by a sub-pixel distance to ensure continuous stitching and surface accuracy of the stitched portion. This stitching method avoids overexposure and seam defects that occur during DLP projection stitching, while ensuring stitching accuracy between the two different forming methods (DLP projection and SLA scanning), achieving the process goal of integrating high efficiency and high precision into a single device.

[0038] Step S5: Combining steps S3 and S4, plan the hybrid process forming path. Using a global path planning algorithm, considering the working area division in step S3 and the constraints of the overlapping splicing area pixels in step S4, the path planning for the hybrid process forming is obtained.

[0039] Step S6: As Figure 6 , Figure 7As shown, the gantry displacement system 7 drives the DLP optical engine projection system 8 and the SLA galvanometer scanning system 9 to move synchronously. The DLP optical engine projection system 8 projects and cures the photosensitive resin. Simultaneously, based on the working area divided in step S3 above, the DLP optical engine projection system 8 and the SLA galvanometer scanning system 9, along with their working surfaces, determine whether to simultaneously perform SLA laser scanning and curing. Figure 6 , Figure 7 As shown, the working areas of the DLP optical engine projection system 8 and the SLA galvanometer scanning system 9 do not overlap, thus enabling synchronous operation. Since the DLP optical engine projection system 8 and the SLA galvanometer scanning system 9 are simultaneously mounted on the gantry moving platform, the working area can be expanded, achieving large-format printing.

[0040] Step S7: Perform SLA laser scanning and curing molding according to the working area defined in Step S3 above. The hybrid process method described in this invention relies on a synchronously moving DLP optomechanical projection system 8 and an SLA galvanometer scanning system 9. For the SLA galvanometer scanning system 9, the workflow is as follows: after determining the reference origin, establish the coordinate system of the working area, then calculate the coordinates of each scanning point, convert them into galvanometer deflection angles, so that the laser achieves the scanning effect. Therefore, for the SLA galvanometer scanning system 9 in the moving coordinate system, the coordinates of the center of the SLA galvanometer scanning system 9 at the current working position are calculated by the laser rangefinder and encoder installed on the gantry displacement system. After aligning with the corresponding coordinates of the SLA working area on the target slice, the angle of the scanning feature is calculated, and the work is performed. The movable SLA galvanometer scanning system 9 greatly reduces the working distance of the SLA galvanometer scanning system 9, which can avoid interference between the large-format SLA scanning optical path and the DLP optomechanical projection system 8, and at the same time extend high-precision molding to the entire molding plane, which is a key technology for realizing the hybrid molding process.

[0041] like Figure 6 and 7 As shown, a hybrid process photopolymerization molding system includes a gantry displacement system, on which a DLP optomechanical projection system and an SLA galvanometer scanning system are installed. The DLP optomechanical projection system is responsible for large-scale feature molding, while the SLA galvanometer scanning system is responsible for high-precision feature molding.

[0042] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A method for splicing additive manufacturing processes using a hybrid SLA and DLP technology, characterized in that: The method includes the following steps: S1: Read the test slice image and perform power modulation on the DLP optical-mechanical projection system (8) and the SLA galvanometer scanning system (9); S2: Determine whether the curing depth of the DLP optical engine projection system (8) and the SLA galvanometer scanning system (9) is consistent, and adjust the power of the DLP optical engine projection system (8) and the SLA galvanometer scanning system (9); S3: Import the 3D model, obtain the 2D slice image of the 3D model, and divide the DLP projection working area (3) and SLA scanning working area (4); S4: Based on the DLP projection working area (3) and the SLA scanning working area (4), the DLP projection splicing overlap area and the DLP and SLA curing boundary splicing overlap area are calculated respectively; grayscale modulation is performed on the DLP projection splicing overlap area and the DLP and SLA curing boundary splicing overlap area to eliminate the gaps generated during the splicing process. For the forming and splicing of DLP projection and SLA laser spot, the laser scanning boundary of SLA is offset to the DLP projection pixel by a sub-pixel level distance to ensure the continuous forming and surface accuracy of the spliced ​​part. S5: Based on the DLP projection working area (3), SLA scanning working area (4), DLP projection splicing overlap area, and DLP and SLA curing boundary splicing overlap area, plan the molding path of the DLP and SLA hybrid process. S6: The DLP optical engine projection system (8) projects according to the process forming path, and the SLA galvanometer scanning system (9) scans according to the process forming path.

2. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: The projection pixel size of the DLP optical engine projection system (8) is 78μm×78μm.

3. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: The laser galvanometer in the SLA galvanometer scanning system (9) has a spot diameter of 10 μm.

4. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: In S1, the projection of the DLP optical engine projection system (8) and the laser spot energy distribution of the SLA galvanometer scanning system (9) both follow a Gaussian distribution.

5. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: In step S2, the curing depth of the DLP optical-mechanical projection system (8) and the SLA galvanometer scanning system (9) is compared using an electron microscope to determine whether the power of the DLP optical-mechanical projection system (8) and the SLA galvanometer scanning system (9) should be adjusted.

6. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: In S3, the DLP projection working area (3) and the SLA scanning working area (4) are divided according to the scale of the printed features in the two-dimensional slice image. The DLP optical engine projection system (8) is responsible for large-scale feature shaping, and the SLA galvanometer scanning system (9) is responsible for high-precision feature shaping.

7. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: In S5, a global path planning algorithm is used to consider the constraints of the DLP projection working area (3), the SLA scanning working area (4), the DLP projection splicing overlap area, and the DLP and SLA curing boundary splicing overlap area pixels to obtain the path planning for the DLP and SLA hybrid process forming.

8. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: In step S6, the DLP optical engine projection system (8) and the SLA galvanometer scanning system (9) are moved synchronously by the gantry displacement system (7). The DLP optical engine projection system (8) projects and cures the photosensitive resin. At the same time, it is determined whether to perform laser scanning and curing of the SLA galvanometer scanning system (9) simultaneously based on the working area of ​​the DLP projection (3), the working area of ​​the SLA scanning (4), the working area of ​​the DLP optical engine projection system (8), and the working area of ​​the SLA galvanometer scanning system (9). The SLA galvanometer scanning system (9) performs laser scanning and curing based on the working area of ​​the SLA scanning (4).

9. The additive manufacturing splicing method using a hybrid SLA and DLP process according to claim 1, characterized in that: The method uses a hybrid process photopolymerization molding system, which includes a gantry displacement system (7). The gantry displacement system (7) is equipped with a DLP optical-mechanical projection system (8) and an SLA galvanometer scanning system (9). The DLP optical-mechanical projection system (8) is responsible for large-scale feature molding, and the SLA galvanometer scanning system (9) is responsible for high-precision feature molding.

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