Laser ink-jet composite additive manufacturing dot matrix selection enhancement and precise renovation forming method

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly relates to a laser ink-jet composite additive manufacturing dot matrix selection enhancement and precise renovation forming method. According to the forming method, when a printing model is subjected to layered slicing, a strengthening area of each slice layer is designed through a strengthening structure expert database, laser scanning path planning is carried out, in the forming process, low-power laser is adopted to scan the strengthening areas layer by layer, adhesive curing is accelerated, and a net-shaped strengthening structure is accurately constructed to support an integral workpiece; laser power is increased to scan along the inner and outer contours of the workpiece, so that the adhesive is quickly carbonized to lose efficacy, and redundant parts are precisely cut and permeated. According to the forming method, the problem that a workpiece needs to stand for a long time in a forming space to be cured after traditional micro-droplet jet sand mold 3D printing or ceramic adhesive 3D printing is completed is solved, high-precision, high-efficiency and high-quality preparation of a complex sand mold / ceramic workpiece can be achieved, and further application and popularization of an adhesive ink-jet 3D printing technology are facilitated.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a method for selective enhancement and precise shaping of laser inkjet composite additive manufacturing lattice. Background Technology

[0002] Sand mold 3D printing technology based on the microdroplet jetting principle includes process steps such as design model, model slicing, sand laying and inkjet spraying, sand mold demolding and drying and sintering. This technology realizes sand mold additive manufacturing by laying sand particles layer by layer and selectively spraying resin binder. It uses the cross-linking reaction of resin curing agent to bond sand particles and prepare complex sand molds. In traditional casting processes, sand molds are mostly prepared by manual mold making, which is a complicated process. Sand mold 3D printing technology has greatly improved production efficiency, reduced costs and risks, and brought about a huge change to the traditional casting industry. However, when using this technology to prepare sand molds, there are still the following problems: (1) The resin cures slowly. The printed sand mold often needs to stand for several days or even longer before it is strong enough to support its removal from the molding chamber, which greatly affects production efficiency. (2) Before the sand mold is fully cured, the resin will continue to penetrate and diffuse in the sand particles, causing a certain dimensional deviation between the sand mold after printing and the designed model.

[0003] Ceramic adhesive 3D printing technology is similar to sand mold 3D printing technology based on the principle of microdroplet jetting. It uses rollers to pre-spread ceramic powder, and then the adhesive is sprayed from the nozzle according to the cross-sectional shape of the part, so that the powder is bonded together to form the shape of the part. Layer by layer until the designed three-dimensional model is formed. This technology is limited by the bonding strength of the adhesive, which also limits the strength of the component.

[0004] Therefore, sand mold 3D printing and ceramic inkjet forming have similar problems. On the one hand, the formed parts need to be left for a long time to fully cure, which seriously affects production efficiency. On the other hand, the precision of the formed parts is limited. CN115971512A, a method and apparatus for composite forming of casting sand mold microdroplet jetting and high-energy beam, proposes a solution. This solution is for sand mold printing. After each layer of resin binder is jetted, the high-energy beam system is driven to scan along the inner and outer contours of the current layer's cross-sectional pattern, so that the inner and outer contour temperatures of the sand mold reach the resin failure temperature, thereby completing the precise forming of the current layer's pattern. This solution improves the surface precision of the sand mold to some extent, but it still fails to solve the problem of slow sand mold removal. At the same time, the ablation temperature that causes the binder to fail is usually very high. Excessively high temperature diffusion can easily cause the surrounding sand mold to fracture brittlely, resulting in a decrease in strength instead of an increase, which seriously affects the overall strength of the sand mold. CN110328364A proposes an additive manufacturing method and apparatus for ceramics and their composites, which proposes a rapid printing scheme for ceramic materials. However, by heating the entire substrate through preheating, it is impossible to perform discrete and patterned energy input, resulting in limited control over forming accuracy. At the same time, the temperature window is narrow and strongly bound to the melting point of the material, which can easily cause overheating or failure. Furthermore, it is not suitable for sand mold 3D printing.

[0005] Therefore, a novel auxiliary printing method is proposed for sand mold / ceramic printing technology based on inkjet forming. This method is applicable to both printing processes. During the sand mold / ceramic inkjet printing process, low-power lasers are used layer by layer to heat and strengthen the printing area, while higher-power lasers are used layer by layer to precisely cut along the inner and outer contours of the sand mold. This laser-assisted forming method allows the sand mold / ceramic to reach the required strength for removal from the forming stage in a shorter time. Simultaneously, the precise welding and cutting of the inner and outer contours significantly improves the dimensional accuracy and surface quality of the formed parts. This facilitates the further realization of high-precision, high-efficiency, and high-quality inkjet printing of sand molds / ceramics, and helps to meet the rapid response requirements for printing high-end, complex parts using sand mold / ceramic inkjet printing. Summary of the Invention

[0006] To address the aforementioned issues, this invention discloses a laser-inkjet composite additive manufacturing method for selective enhancement and precise shaping of a laser-heated strengthening matrix. This method utilizes a heat-strengthening structure expert database to generate and plan the laser-heated strengthening area for each printed layer thickness. Low-power lasers are used for interlayer mesh-like heat strengthening via CNC commands, while high-power lasers are used to precisely and rapidly cut the printed part layer by layer via CNC commands. The sand mold / ceramic parts prepared by this inkjet additive and laser manufacturing method possess sufficient strength to be removed from the forming space for subsequent processes in a short time, while also exhibiting high forming accuracy, enabling the production of high-quality parts.

[0007] To achieve the above objectives, a laser-inkjet composite additive manufacturing lattice selective enhancement and precision shaping method is provided, which includes the following steps:

[0008] Step 1: Slice the 3D model of the target part into layers to obtain 2D planar data of the 3D model at different heights, and generate the first control command for spraying the adhesive on demand on each layer of powder bed based on the 2D planar data;

[0009] Step 2: Design reinforcement structures for each two-dimensional plane and generate a second control command to selectively laser heat the structure to form the reinforcement structure;

[0010] Step 3: Based on the inner and outer contour information of each two-dimensional plane, generate a third control command for laser cutting along the two-dimensional contour;

[0011] Step 4: Import the above control commands into the printing system;

[0012] Step 5: Lay a layered powder bed in the forming space and level the powder bed;

[0013] Step 6: Spray adhesive as needed according to the first control command of the current layer;

[0014] Step 7: Using a low-power laser according to the second control command, the current printing layer is heated and strengthened by interlayer heating to pre-build a mesh reinforcement structure inside the sand mold;

[0015] Step 8: Increase the laser power. The high-power laser scans the inner and outer contours of the current printing layer according to the third control command. The high temperature causes the adhesive at the contour line position to carbonize and fail.

[0016] Step 9: The forming space decreases by one layer thickness;

[0017] Step 10: Repeat steps 5-9, layer by layer, until all printing layers are completed;

[0018] Step 11: After printing, the failed outlines overlap to form a closed failed surface. The mesh reinforcement structure obtained by low-power laser interlayer heating strengthens the overall part with high strength. The part is then removed and post-processed for later use.

[0019] As a further design of this solution, the forming method is applicable to both microdroplet jet sand mold 3D printing and ceramic binder 3D printing;

[0020] As a further design of this solution, the second control command in step 2 and the third control command in step 3 are the same beam or the same group of lasers, which are executed sequentially by a single laser beam or synchronously by multiple laser beams;

[0021] As a further design of this solution, the specific steps for designing the reinforcement structure in step 2 are as follows: obtain the preset parameter configuration of the reinforcement structure design that has been preset or stored in the reinforcement structure expert library, configure the parameters of each two-dimensional planar contour obtained by slicing according to the shape and structural features, and configure the parameters including the structure shape, structure size and scanning path. The reinforcement effect and production efficiency of the reinforcement structure are comprehensively considered during the design.

[0022] As a further design of this solution, the reinforcement structure includes a matrix structure, a honeycomb structure, a foam biomimetic structure, and a structure based on density / boundary topology optimization. One type of reinforcement structure is selected for each two-dimensional plane. When subjected to uniformly distributed loads and in-plane tension / compression, a matrix structure is selected. When it needs to withstand large loads, a honeycomb structure is selected. When subjected to multi-directional loads, concentrated loads, and complex stress distributions, a structure based on density / boundary topology optimization is used. When there are special functional requirements such as heat dissipation, a foam biomimetic structure is selected.

[0023] As a further design of this scheme, when using microdroplet jet sand mold 3D printing, the layer thickness in step 5 is 0.3-0.6 mm, and the powder bed is a uniformly mixed molding sand particles and curing agent, wherein the molding sand particles are one or more of quartz sand, chromite sand, zircon sand, ceramsite sand, limestone sand, corundum sand, magnesia sand, and refractory clinker sand, and the curing agent content is 2.0-5.0 wt.‰; when using ceramic binder 3D printing, the layer thickness in step 5 is 0.02-0.30 mm, and the powder bed material is one of alumina, zirconium oxide, silicon carbide, silicon nitride, titanium dioxide, barium carbonate, or hydroxyapatite ceramic powder;

[0024] As a further design of this solution, the powder bed in step 5 can be leveled by a scraper or roller;

[0025] As a further design of this solution, if microdroplet jet sand mold 3D printing is performed, then the binder in step 6 is one of furan resin, phenolic resin, or urea resin, and the binder content is 1.0–5.0 wt.%; if ceramic binder 3D printing is performed, then the binder in step 6 is one of paraffin wax, polyvinyl acetate, polyvinyl alcohol, polyethyleneimine, or polyvinylpyrrolidone.

[0026] As a further design of this scheme, the low-power laser in step 7 and the high-power laser in step 8 are both emitted by a laser emitter. The power of the laser emitter is adjustable to achieve both low-power laser heating and high-power laser cutting effects. The heating temperature of the laser emitter on the powder bed is 50-400 ℃, and the scanning speed of the laser emitter is 0-100 mm / s. The heating temperature of the low-power laser is 50-250 ℃, and the heating temperature of the high-power laser is 250-400 ℃.

[0027] As a further design of this scheme, if microdroplet jet sand mold 3D printing is performed, the post-processing in step 11 is overall baking of the sand mold at a baking temperature of 100-200 ℃; if ceramic binder 3D printing is performed, the post-processing in step 11 includes curing, debinding, and densification steps. Curing is carried out by means of heating, ultraviolet light irradiation, or pressure, with a curing temperature of 120-200 ℃. Debinding aims to decompose the binder by heating, with a debinding temperature of 600-800 ℃.

[0028] This invention overcomes two major technical bottlenecks in traditional adhesive spraying additive manufacturing: low green strength and poor contour accuracy. Its core innovation lies in proposing a new paradigm of "integrated digital strengthening and finishing within the process." This is specifically reflected in the following three aspects:

[0029] (1) In traditional processes, full-area heating is used to strengthen the interlayer of printed parts. The heating device is bulky, has low heating efficiency, and consumes a lot of resources. The present invention selectively forms a strengthening network on the forming surface during the printing process, so as to achieve the purpose of rapid removal of the printed blank and improve production efficiency.

[0030] (2) In traditional processes, printed parts often need to undergo subtractive processing after printing to achieve higher forming accuracy. This invention uses a high-power laser to perform in-situ shaping after each layer is printed, eliminating the need for subsequent finishing work and solving the problem of sand adhering to the surface contour.

[0031] (3) In traditional processes, printing and precise cutting require different equipment, making the system complex. This invention creatively uses the same laser source, and only the power density of the laser emitter needs to be adjusted according to the working conditions to realize the two processes of heating and cutting, which effectively reduces the development and maintenance costs of the equipment and improves the integration of the equipment. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the basic steps of the laser inkjet composite additive manufacturing lattice selective enhancement and precision finishing forming method described in an embodiment of the present invention.

[0033] Figure 2These are schematic diagrams of four typical design schemes of the mesh heating and strengthening structure described in the embodiments of the present invention.

[0034] Figure 3 This is the design result of the 50th layer of the heating and strengthening region of the silica sand cylindrical sample in Example 1 of the present invention.

[0035] Figure 4 This is the design result of the 300th layer of the alumina ceramic impeller in Embodiment 2 of the present invention. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0037] like Figure 1 and Figure 2 As shown, a laser-inkjet composite additive manufacturing method for lattice selective enhancement and precision finishing includes the following steps:

[0038] A three-dimensional geometric model of the target part in STL format is created using CAD software. The three-dimensional model is then sliced ​​into layers to obtain the two-dimensional planar contours of the three-dimensional model at different heights. A mesh-like heat-strengthening structure is designed for all two-dimensional planes. The CAD / CAM software system generates motion numerical control commands for laser beams to heat and strengthen each printed surface based on the mesh-like heat-strengthening structure. The specific steps of the mesh-like heat-strengthening structure design are as follows: First, the preset parameter configurations of heat-strengthening structure designs that have been preset or stored in the heat-strengthening structure expert database are obtained. Then, the parameters of each two-dimensional plane contour obtained by slicing are configured according to its shape and structural characteristics. The configured parameters include the shape information, size information and laser scanning path of the heat-strengthening structure. The design comprehensively considers the strengthening effect and production efficiency of the mesh-like heat-strengthening structure on the overall part. The mesh-like heat-strengthening structure includes matrix heat-strengthening structure, honeycomb heat-strengthening structure, foam biomimetic heat-strengthening structure and density / boundary topology optimization-based heat-strengthening structure. When subjected to uniform load and in-plane tension / compression, the matrix structure is selected; when it needs to withstand large loads, the honeycomb structure is selected; when subjected to multi-directional loads, concentrated loads and complex stress distributions, the density / boundary topology optimization-based structure is used; and when there are special functional requirements such as heat dissipation, the foam biomimetic structure is selected. The CAD / CAM software system generates motion CNC commands for laser cutting on each printed surface based on the two-dimensional planar contour information. Both the heating and strengthening CNC commands and the laser cutting CNC commands can be generated by scanning point by point with a single laser beam, or by multiple laser beams working together to generate CNC commands. Multiple laser beams simultaneously perform heating and strengthening and cutting to improve efficiency. Information such as the two-dimensional planar contour, slice thickness, heating and strengthening CNC instructions, and laser cutting CNC instructions are imported into the printing system. A powder bed of varying thickness is laid in the forming space and leveled by a scraper or roller. If micro-droplet jet sand mold 3D printing is performed, the layer thickness is 0.3–0.6 mm. The powder bed consists of uniformly mixed molding sand particles and a curing agent. The molding sand particles are one or more of the following: quartz sand, chromite sand, zircon sand, ceramsite sand, limestone sand, corundum sand, magnesia sand, and refractory clinker sand. The curing agent content is 2.0–5.0 wt.‰. If ceramic binder 3D printing is performed, the layer thickness is 0.02–0.30 mm. The powder bed material includes alumina, zirconium oxide, silicon carbide, silicon nitride, titanium dioxide, barium carbonate, or hydroxyapatite ceramic powder. Based on the current layer's two-dimensional planar contour, inkjet adhesive is applied on demand. If micro-droplet jet sand mold 3D printing is being performed, the adhesive is furan resin, phenolic resin, or urea resin, etc., with an adhesive content of 1.0–5.0 wt.%; if ceramic adhesive 3D printing is being performed, the main components of the adhesive are paraffin wax, polyvinyl acetate, polyvinyl alcohol, polyethyleneimine, polyvinylpyrrolidone, etc.Using a low-power laser, based on CNC heating and strengthening instructions, the current printing layer is heated and strengthened interlayer, pre-building a well-cured and high-strength mesh reinforcement structure inside the sand mold. The laser power is then increased, and a high-power laser, based on laser cutting CNC instructions, scans the inner and outer contours of the part in the current printing layer. The high temperature causes the binder at the contour lines to carbonize and fail, while the powder bed not scanned by the laser remains in place to provide support. Both low-power and high-power lasers are emitted from a laser emitter, whose power is adjustable to achieve both low-power laser heating and high-power laser cutting effects. The heating temperature of the laser emitter on the powder bed is 50–400 ℃, and the scanning speed is 0–100 mm / s. The heating temperature of the low-power laser is 50–250 ℃, and the heating temperature of the high-power laser is 250–400 ℃, decreasing the forming space by one layer thickness. Layer-by-layer powder application, inkjet printing, low-power laser heating, and high-power laser cutting are performed until all printing layers are completed. After printing, the superimposed failed contours form a closed failed surface. The mesh-like reinforcement structure obtained by low-power laser interlayer heating strengthens the overall part, giving it high strength. The part is then removed and post-processed for later use. If microdroplet jet sand mold 3D printing is performed, the post-processing is overall sand mold baking at a temperature of 100–200 ℃. If ceramic binder 3D printing is performed, the post-processing includes curing, debinding, and densification. Curing is carried out by heating, ultraviolet light irradiation, or pressure at a temperature of 120–200 ℃. Debinding aims to decompose the binder by heating at a temperature of 600–800 ℃.

[0039] Example 1: A cylindrical silica sand sample with a diameter of 50 mm and a height of 50 mm was printed using this method. (e.g.) Figure 3 As shown,

[0040] A three-dimensional geometric model of the cylindrical specimen in STL format was established using CAD software. The 3D model was then sliced ​​into layers to obtain the two-dimensional planar contours at different heights. Each layer was 0.5 mm thick, for a total of 100 layers. A mesh-like heat-strengthening structure was designed for all two-dimensional planes. Taking the 50th layer of the cylindrical specimen as an example, the design results of its heat-strengthening region are as follows: Figure 3As shown, the black areas represent the heat-strengthened regions, while the shaded areas do not require heat strengthening. The CAD / CAM software system generates motion control commands for laser beam heating on each printed surface based on the mesh-like heat-strengthened structure. The CAD / CAM software system also generates motion control commands for laser cutting on each printed surface based on the two-dimensional planar contour information. Information such as the two-dimensional planar contour, slice thickness, heat strengthening CNC commands, and laser cutting CNC commands are imported into the printing system. 70 / 140 mesh silica sand particles are mixed evenly with a curing agent at a content of 2.2 wt.‰. A layered powder bed is laid in the forming space using a scraper. Furan resin binder, at a content of 2.5 wt.%, is sprayed as needed according to the two-dimensional planar contour of the current layer. A 15 W low-power laser, based on the heat strengthening CNC commands, scans at a speed of 50 mm / s to perform interlayer heat strengthening on the heat-strengthened areas of the current printed layer. The sand surface temperature in the scanning area is 150 ℃, pre-building a sufficiently cured and high-strength mesh-like reinforcement structure inside the sand mold. The laser power was increased to 65 W, and the scanning speed was set to 50 mm / s. Using a high-power laser, the inner and outer contours of the part at the current printing layer were scanned according to CNC laser cutting instructions. The scanning position temperature was 300℃. This high temperature caused the adhesive at the contour lines to carbonize and fail, while the powder bed not scanned by the laser remained in place, providing support. Powder was laid layer by layer, inkjet was sprayed, low-power laser heating was applied, and high-power laser cutting was performed until all printing layers were completed. After printing, the failed contour lines overlapped to form a closed failure surface. The mesh-like reinforcement structure obtained by the low-power laser interlayer heating gave the overall part high strength. The part was then removed and baked at 150℃ for later use.

[0041] Example 2: A silicon carbide ceramic impeller with a height of 105 mm was printed using this method, such as... Figure 4 As shown.

[0042] The impeller has a height of 105 mm, a rear end cap diameter of 115 mm, an end cap thickness of 8.5 mm, a blade length of 38 mm, a blade width of 5 mm, and an overall ceramic shell thickness of 3 mm. A three-dimensional geometric model of the cylindrical specimen in STL format was created using CAD software. The three-dimensional model was then sliced ​​to obtain two-dimensional planar contours at different heights, with each slice being 0.05 mm thick, for a total of 2100 layers. A mesh-like heat-strengthening structure was designed for all two-dimensional planes. Taking the 300th layer of the impeller as an example, the design results of its heat-strengthening area are as follows: Figure 4As shown, the black areas represent the heat-strengthened regions, while the shaded areas do not require heat strengthening. The CAD / CAM software system generates motion CNC commands for the laser beam to perform heat strengthening on each printed surface based on the mesh-like heat-strengthened structure. The CAD / CAM software system also generates motion CNC commands for laser cutting on each printed surface based on the two-dimensional planar contour information. Information such as the two-dimensional planar contour, slice thickness, heat strengthening CNC commands, and laser cutting CNC commands are imported into the printing system. Alumina ceramic powder is selected, with its main components including Al2O3 (≥99.3%), Na2O (≤0.29%), Fe2O3 (≤0.03%), and SiO2 (≤0.05%). 800-mesh alumina ceramic powder is mechanically mixed in a planetary ball mill for 2 hours at a ball-to-powder ratio of 5:1 and a mill speed of 180 r / min. After uniform mixing, the powder is dried in a vacuum drying oven at 200 ℃ for 2 hours. After drying, the powder is sieved to remove large particles and impurities. The mixed powder is then placed in a moisture-proof box, and a layered powder bed is laid in the forming space using rollers. Phenolic resin alcohol-based adhesive is sprayed as needed according to the two-dimensional planar contour of the current layer, with the adhesive saturation at 100%. A 25W low-power laser, following CNC heating and strengthening instructions, scans at a speed of 100 mm / s to perform interlayer heating and strengthening on the current printed layer's heated and strengthened area. The surface temperature of the scanned area is 160℃, pre-building a well-cured and high-strength mesh reinforcement structure inside the ceramic part. The laser power is then increased to 80W, and the scanning speed is 80 mm / s. A high-power laser, following CNC laser cutting instructions, scans the inner and outer contours of the current printed layer's part. The temperature at the scanning position is 350℃. This high temperature causes the adhesive at the contour line to carbonize and fail, while the powder bed not scanned by the laser remains in place, providing support. The process involves layer-by-layer powder application, inkjet printing, low-power laser heating, and high-power laser cutting until all printing layers are completed. After printing, the overlapping failure contours form a closed failure surface. The mesh-like reinforcement structure obtained by low-power laser interlayer heating gives the overall part high strength. The part is then removed and post-processed to obtain an alumina ceramic impeller.

[0043] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A method for selective enhancement and precise shaping of laser-inkjet composite additive manufacturing lattice, characterized in that, The method includes the following steps: Step 1: Slice the 3D model of the target part into layers to obtain 2D planar data of the 3D model at different heights, and generate the first control command for spraying the adhesive on demand on each layer of powder bed based on the 2D planar data; Step 2: Design reinforcement structures for each two-dimensional plane and generate a second control command to selectively laser heat the structure to form the reinforcement structure; Step 3: Based on the inner and outer contour information of each two-dimensional plane, generate a third control command for laser cutting along the two-dimensional contour; Step 4: Import the above control commands into the printing system; Step 5: Lay a layered powder bed in the forming space and level the powder bed; Step 6: Spray adhesive as needed according to the first control command of the current layer; Step 7: Using a low-power laser according to the second control command, the current printing layer is heated and strengthened by interlayer heating to pre-build a mesh reinforcement structure inside the sand mold; Step 8: Increase the laser power. The high-power laser scans the inner and outer contours of the current printing layer according to the third control command. The high temperature causes the adhesive at the contour line position to carbonize and fail. Step 9: The forming space decreases by one layer thickness; Step 10: Repeat steps 5-9, layer by layer, until all printing layers are completed; Step 11: After printing, the failed outlines overlap to form a closed failed surface. The mesh reinforcement structure obtained by low-power laser interlayer heating strengthens the overall part with high strength. The part is then removed and post-processed for later use.

2. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 1, characterized in that, The forming method is applicable to both microdroplet jet sand mold 3D printing and ceramic binder 3D printing.

3. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 1, characterized in that, The second control command in step 2 and the third control command in step 3 are the same laser beam or the same group of laser beams, which can be executed sequentially by a single laser beam or synchronously by multiple laser beams.

4. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 1, characterized in that, The specific steps for designing the reinforcement structure in step 2 are as follows: obtain the preset parameter configurations of the reinforcement structure designs that have been preset or stored in the reinforcement structure expert database; configure the parameters of each two-dimensional planar contour obtained by slicing according to its shape and structural features; the configured parameters include the structure shape, structure size and scanning path; and comprehensively consider the reinforcement effect and production efficiency of the reinforcement structure during the design process.

5. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 4, characterized in that, The reinforcement structure includes a matrix structure, a honeycomb structure, a foam biomimetic structure, and a density / boundary topology optimization-based structure. One type of reinforcement structure is selected for each two-dimensional plane. When subjected to uniformly distributed loads and in-plane tension / compression, a matrix structure is selected. When a large load needs to be borne, a honeycomb structure is selected. When subjected to multi-directional loads, concentrated loads, and complex stress distributions, a density / boundary topology optimization-based structure is used. When there are special functional requirements such as heat dissipation, a foam biomimetic structure is selected.

6. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 2, characterized in that, When using microdroplet jet sand mold 3D printing, the layer thickness in step 5 is 0.3–0.6 mm, and the powder bed consists of uniformly mixed molding sand particles and a curing agent. The molding sand particles are one or more of quartz sand, chromite sand, zircon sand, ceramsite sand, limestone sand, corundum sand, magnesia sand, and refractory clinker sand, and the curing agent content is 2.0–5.0 wt.‰. When using ceramic binder 3D printing, the layer thickness in step 5 is 0.02–0.30 mm, and the powder bed material is one of alumina, zirconium oxide, silicon carbide, silicon nitride, titanium dioxide, barium carbonate, or hydroxyapatite ceramic powder.

7. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 2, characterized in that, If microdroplet jet sand mold 3D printing is performed, the binder in step 6 is one of furan resin, phenolic resin or urea resin, and the binder content is 1.0 to 5.0 wt.%; if ceramic binder 3D printing is performed, the binder in step 6 is one of paraffin wax, polyvinyl acetate, polyvinyl alcohol, polyethyleneimine, or polyvinylpyrrolidone.

8. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 1, characterized in that, Both the low-power laser in step 7 and the high-power laser in step 8 are emitted by a laser emitter. The power of the laser emitter is adjustable to achieve both low-power laser heating and high-power laser cutting effects. The heating temperature of the laser emitter on the powder bed is 50–400 ℃, and the scanning speed of the laser emitter is 0–100 mm / s. The heating temperature of the low-power laser is 50–250 ℃, and the heating temperature of the high-power laser is 250–400 ℃.

9. The laser-inkjet composite additive manufacturing lattice selective enhancement and precision finishing method according to claim 2, characterized in that, If microdroplet jet sand mold 3D printing is performed, the post-processing in step 11 is overall baking of the sand mold at a temperature of 100–200 °C. If ceramic binder 3D printing is performed, the post-processing in step 11 includes curing, debinding, and densification steps. Curing is carried out by heating, ultraviolet light irradiation, or pressure at a temperature of 120–200 °C. Debinding aims to decompose the binder by heating at a temperature of 600–800 °C.

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