Preparation method and application of nano silicon dioxide / wood-plastic composite material for selective laser sintering

Abstract

The invention discloses a preparation method and application of a nano silicon dioxide / wood-plastic composite material for selective laser sintering, relates to a preparation method and application of a polymer wood-plastic composite material for selective laser sintering, and aims to solve the technical problems of high surface roughness and large size deformation of an existing selective laser sintering wood-plastic printing material. The method comprises the following steps: drying poplar powder, carrying out alkali treatment, adding the alkali-treated poplar powder and KH550 into an ethanol solution, carrying out water-bath heating reflux treatment, and drying to obtain the poplar powder treated by KH550; uniformly mixing with pure polyethersulfone powder, calcium carbonate, nano silicon dioxide powder and glycerol, sealing and standing to obtain the composite material. The surface roughness of a part printed by the material through a selective laser sintering process is 7.6-10.6 mu m, the size deformation is 1.7%-4.2%, the tensile strength is 2.4-3.2 MPa, and the hardness is 49-59 HA. The method can be used in the 3D printing field.

Description

Technical Field

[0001] The invention relates to a preparation method and application of a polymer wood-plastic composite material for selective laser sintering, and belongs to the field of additive manufacturing. Background Art

[0002] 3D printing is a cutting-edge technology that integrates digital modeling technology, electromechanical control technology, information technology, materials science and chemistry, and many other fields. It is a kind of rapid prototyping technology and is known as the core technology of the "third industrial revolution". Compared with traditional manufacturing technology, 3D printing does not require the manufacture of molds in advance, does not need to remove a large amount of material during the manufacturing process, and does not need to be processed through complex forging processes. Instead, special materials are used and the final product can be obtained by selectively bonding and stacking layer by layer. Therefore, structural optimization, material saving and energy saving can be achieved in production. Due to the advantages of 3D printing such as high precision, short cycle, low cost and high shape flexibility, it has been widely used in technical manufacturing, cultural advertising creativity, military defense, biomass medicinal materials, architectural design, and primary and secondary school courses, and plays an irreplaceable role.

[0003] Selective laser sintering (SLS) technology is an additive manufacturing technology based on powder materials. It uses a high-power laser beam to selectively sinter powder materials layer by layer to gradually build complex three-dimensional objects. The key steps of SLS technology are: first, a layer of fine powder material is evenly spread on the printing platform, and then the laser beam accurately scans and heats the powder according to the 3D model designed by the computer, partially melting it and solidifying it into a solid shape. Then, the platform moves down, a new layer of powder material is laid, and the sintering process is repeated until the entire object is completed. One of the biggest advantages of SLS technology is that it can print very complex geometries, including internal structures and holes, without the need for traditional support structures, because the unmelted powder material naturally acts as a support material, avoiding the complex post-processing work caused by the support structure in the traditional method.

[0004] SLS technology has significant advantages in manufacturing complex structures and customized parts, but the surface of the parts printed by it is usually rough, which is a major disadvantage of this technology. In the SLS process, the laser sinters the material powder layer by layer, and the interface bonding between the powder particles causes obvious particle traces on the surface of the part, which in turn produces a high surface roughness, which cannot directly meet the high appearance quality and precision requirements. This makes the printed parts usually need to undergo post-processing processes such as mechanical grinding, sandblasting, and polishing to improve surface smoothness and precision. These post-processing steps not only increase production time and cost, but may also affect the precision and shape of the parts. Especially in some applications that require high precision and good surface finish, SLS-printed parts may have problems with large friction, affecting their functionality and durability. Therefore, improving SLS printing technology, optimizing materials and processes to reduce surface roughness and reduce post-processing requirements have become key directions for improving the performance and application scope of this technology. Summary of the invention

[0005] The present invention aims to solve the technical problems of high surface roughness and large dimensional deformation of existing selective laser sintering wood-plastic printing materials, and provides a preparation method and application of nano-silicon dioxide / wood-plastic composite materials for selective laser sintering. The present invention adds wood powder with a wide range of sources and abundant resources to traditional plastics to reduce printing costs. Nano-silicon dioxide is then added to improve the surface roughness of the printed product, reduce the post-processing process, and enhance its mechanical properties.

[0006] The method for preparing the nano-silicon dioxide / wood-plastic composite material for selective laser sintering of the present invention is carried out according to the following steps:

[0007] 1. Grind the poplar wood into powder and vacuum dry it to obtain dry poplar wood powder; then mix the dried poplar wood powder with sodium hydroxide solution, stir for 20 to 24 hours, let it stand, pour off the upper alkali solution, wash the poplar wood powder with distilled water until the filtrate is neutral, and then dry the poplar wood powder to obtain alkali-treated poplar wood powder;

[0008] 2. Mix anhydrous ethanol and distilled water in a mass ratio of (2.5-3.5):1 to obtain an ethanol solution; add HCl aqueous solution to the ethanol solution to adjust the pH of the solution to 3.5-4.5, then add alkali-treated poplar wood powder and silane coupling agent KH550 and mix them evenly, let stand at room temperature for 10-30 minutes, transfer to a three-necked flask for water bath reflux treatment, the reflux temperature is 82-88°C, and the reaction time is 4-5h; after the reflux is completed, let stand and pour out the upper liquid, remove the solution by vacuum filtration, wash the poplar wood powder with ethanol until the filtrate is neutral, and finally dry the poplar wood powder at a temperature of 60-65°C, and then heat it to 100-105°C for aging until the water content of the wood powder by mass reaches less than 2%, to obtain the poplar wood powder treated with the silane coupling agent KH550;

[0009] 3. Weigh 72% to 81% of pure polyether sulfone (PES) powder, 8% to 12% of KH550 treated poplar wood powder, 4.5% to 5.5% of calcium carbonate, 3% to 6% of nano-silicon dioxide powder, and 3.5% to 4.5% of lubricant glycerol according to mass percentage, add them into a blender and mix evenly, then seal and let stand for 20 to 24 hours to obtain a nano-silicon dioxide / wood-plastic composite material for selective laser sintering.

[0010] Furthermore, the vacuum drying in step 1 is performed at a temperature of 80° C. for 24 hours.

[0011] Furthermore, the drying in step 1 is carried out at a temperature of 80° C. for 24 hours.

[0012] Furthermore, the pure polyether sulfone (PES) powder described in step 3 has a fineness of 150 μm to 250 μm and uniform particles to promote full fusion of the components during the mixing process.

[0013] Furthermore, the fineness of the calcium carbonate in step 3 is 30 μm to 60 μm, and the purity by mass percentage is greater than 99.0%. Calcium carbonate with higher fineness and better purity can ensure its good dispersibility in the composite material to improve the deformability of the material.

[0014] Furthermore, the average particle size of the nano-silicon dioxide powder described in step three is 300nm to 350nm, so as to improve the surface finish and mechanical properties of the material.

[0015] The application of the nano-silica / wood-plastic composite material for selective laser sintering prepared above is to 3D print the nano-silica / wood-plastic composite material through selective laser sintering technology. Specifically: create a model file of the part to be 3D printed through modeling software, then import the model into slicing software, set printing parameters, and the slicing software will layer the model, generate the printing path of each layer, and output it as a G code file, which is an instruction set for controlling the movement of the printer; then transmit the G code to the 3D printer, evenly put the nano-silica / wood-plastic composite material into the hopper of the selective laser sintering printer, and before starting printing, preheat the printer to the set temperature, and then scan and print layer by layer to obtain the nano-silica / wood-plastic composite material parts.

[0016] Furthermore, printing parameters include layer height, filling density, printing speed and support structure.

[0017] Furthermore, the preheating setting temperature is 85°C.

[0018] Furthermore, the scanning speed during layer-by-layer scanning printing is 2000.

[0019] Furthermore, the laser power of the selective laser sintering printer is 6 to 20W.

[0020] The present invention significantly improves the comprehensive performance of the composite material by introducing a silane coupling agent to modify the wood powder and PES composite material. The silane coupling agent forms a chemical bonding layer on the surface of the wood powder, thereby enhancing the interfacial bonding force between the wood powder and the polyethersulfone matrix, improving the compatibility of the two, and thus improving the mechanical properties of the composite material. In addition, the modified composite material exhibits better anti-aging performance and more uniform wood powder dispersibility, optimizes processing performance, and reduces defects in processing. The addition of nano-silicon dioxide significantly reduces the surface roughness and dimensional deformation of the printed specimen, mainly by promoting more uniform heat conduction during the sintering process. The uniform dispersion of nano-silicon dioxide particles in the composite material enhances the interfacial bonding force between the wood powder and the polymer matrix, improves the surface finish of the material, and effectively reduces the surface unevenness caused by thermal stress, while improving the mechanical properties. The surface roughness of the parts printed by the selective laser sintering process using nano-silica / wood-plastic composite materials is 7.6-10.6μm, the dimensional deformation is 1.7%-4.2%, the tensile strength is 2.4-3.2MPa, and the hardness is 49-59HA. Through the selective laser sintering process, nano-silica / wood-plastic composite materials can achieve higher precision molding and obtain more stable and uniform product quality.

[0021] The preparation method of the invention is simple and has low production cost, and is an environmentally friendly method for preparing a selective laser sintering material with broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Modeling slice diagrams for 3D printing;

[0023] Figure 2 This is the surface roughness diagram of composite materials with different contents of nano-silicon dioxide;

[0024] Figure 3 It is the size deformation diagram of composite materials with different contents of nano-silicon dioxide;

[0025] Figure 4 It is the maximum load diagram of composite materials with different contents of nano-silica;

[0026] Figure 5 This is the tensile strength diagram of nano-silica composite materials with different contents;

[0027] Figure 6 This is a graph showing the hardness of silicon composite materials with different contents of nano-dioxide. DETAILED DESCRIPTION

[0028] The beneficial effects of the present invention will be verified below with reference to specific embodiments.

[0029] Example 1: The preparation method of the nano-silicon dioxide / wood-plastic composite material for selective laser sintering in this example is carried out according to the following steps:

[0030] 1. Grind the poplar wood into a powder with a fineness of 100 mesh, place it in a vacuum drying oven at a temperature of 80°C and vacuum dry it for 24 hours to obtain dry poplar wood powder; take 150g of the dried poplar wood powder and mix it with a sodium hydroxide solution with a mass fraction of 10% at a mass ratio of 1:15, stir it at room temperature for 24 hours, let it stand after stirring, pour out the upper alkali solution, wash the poplar wood powder with distilled water, filter it with a filter cloth, repeat several times, measure the filtrate with pH test paper until it is neutral, and then place the poplar wood powder in a constant temperature oven at 80°C and dry it for 24 hours to obtain alkali-treated poplar wood powder;

[0031] 2. Anhydrous ethanol and distilled water are mixed in a mass ratio of 3:1 to obtain an ethanol solution; HCl aqueous solution is added dropwise to the ethanol solution to adjust the pH value of the solution to 4, and then alkali-treated poplar powder and KH550 are added and mixed evenly, wherein the mass ratio of alkali-treated poplar powder to KH550 is 9:1, after standing and hydrolyzing at room temperature for 10 minutes, the mixture is transferred to a three-necked flask with a condenser and a stirrer for water bath stirring and reflux treatment, the water bath temperature is 85°C, and the reaction time is 4 hours; after the reflux is completed, the mixture is allowed to stand and the upper layer of liquid is poured off, the solution is removed by vacuum filtration, the poplar powder is washed with ethanol until the filtrate is neutral, and finally the poplar powder is dried at a temperature of 60°C, and then the temperature is raised to 100°C for aging for 12 hours. The moisture content of the wood powder after aging is 1.8% by mass, and the poplar powder treated with silane coupling agent KH550 is obtained;

[0032] 3. Weigh 40g of KH550-treated poplar wood powder, 20g of plasticizer calcium carbonate with an average particle size of 50μm, 16g of glycerol as a lubricant, 6g of nano-silicon dioxide with an average particle size of 300nm, and 318g of powdered pure polyethersulfone with an average particle size of 220μm; add the above components into a blender in turn and stir for 1h to ensure that all components are fully mixed to form a mixture with good consistency; transfer the stirred mixture into a packaging bag and leave it at room temperature for 24 hours to allow the components to fully react and mix, so as to obtain a nano-silicon dioxide / wood-plastic composite material for selective laser sintering.

[0033] Example 2: The difference between this example and Example 1 is that in step 3, 40g of poplar wood powder treated with KH550, 20g of plasticizer calcium carbonate with an average particle size of 50μm, 16g of glycerol as a lubricant, 12g of nano-silicon dioxide with an average particle size of 300nm, and 312g of powdered pure polyethersulfone with an average particle size of 220μm are weighed; the other steps and parameters are the same as in Example 1, and a nano-silicon dioxide / wood-plastic composite material for selective laser sintering is obtained.

[0034] Example 3: The difference between this example and Example 1 is that in step 3, 40g of poplar wood powder treated with KH550, 20g of plasticizer calcium carbonate with an average particle size of 50μm, 16g of glycerol as a lubricant, 18g of nano-silicon dioxide with an average particle size of 300nm, and 306g of powdered pure polyethersulfone with an average particle size of 220μm are weighed; the other steps and parameters are the same as in Example 1, and a nano-silicon dioxide / wood-plastic composite material for selective laser sintering is obtained.

[0035] Example 4: The difference between this example and Example 1 is that in step 3, 40 g of poplar wood powder treated with KH550, 20 g of plasticizer calcium carbonate with an average particle size of 50 μm, 16 g of glycerol as a lubricant, 24 g of nano-silicon dioxide with an average particle size of 300 nm, and 300 g of powdered pure polyethersulfone with an average particle size of 220 μm are weighed; the other steps and parameters are the same as in Example 1, and a nano-silicon dioxide / wood-plastic composite material for selective laser sintering is obtained.

[0036] Example 5: The difference between this example and Example 1 is that in step 3, 40g of poplar wood powder treated with KH550, 20g of plasticizer calcium carbonate with an average particle size of 50μm, 16g of glycerol as a lubricant, 30g of nano-silicon dioxide with an average particle size of 300nm, and 294g of powdered pure polyethersulfone with an average particle size of 220μm are weighed; the other steps and parameters are the same as in Example 1, and a nano-silicon dioxide / wood-plastic composite material for selective laser sintering is obtained.

[0037] Comparative example: The difference between this comparative example and Example 1 is that in step 3, 40g of poplar wood powder treated with KH550, 20g of calcium carbonate with an average particle size of 50μm as a plasticizer, 16g of glycerol as a lubricant, 0g of nano-silicon dioxide, and 324g of powdered pure polyethersulfone with an average particle size of 220μm are weighed; the other steps and parameters are the same as in Example 1, and a wood-plastic composite material for selective laser sintering is obtained.

[0038] The wood-plastic composite material of the comparative example and the nano-silicon dioxide / wood-plastic composite material prepared in Examples 1 to 5 were respectively used for 3D printing by selective laser sintering. Specifically, a model file of a dumbbell-shaped specimen to be 3D printed was created by a modeling software. The dumbbell-shaped specimen had a total length of 165 mm, a width of 19 mm at both ends, a gauge length of 50 mm, a width of 13 mm in the middle test portion, and a thickness of 3.2 mm. The photo of the 3D printed modeling sample is shown in Figure 1 As shown; then the model is imported into the slicing software, the slicing software will layer the model, generate the printing path of each layer, and output it as a G code file, which is an instruction set for controlling the movement of the printer; then the G code is transferred to the 3D printer using a USB flash drive, and the wood-plastic composite material or nano-silicon dioxide / wood-plastic composite material is evenly placed in the hopper of the selective laser sintering printer, which is a laser selective sintering 3D printer CX-A200 of Harbin Freedom Intelligent Manufacturing Technology Development Co., Ltd., and the printing parameters are set, the layer height is 0.1mm, the filling density is 100%, the laser power is adjusted to 6.4W, the scanning speed is set to 2000, and the set temperature is 85℃; before starting printing, the printer is preheated to the set temperature of 85℃, and then scans and prints layer by layer to obtain dumbbell-shaped wood-plastic composite material specimens or dumbbell-shaped nano-silicon dioxide / wood-plastic composite material specimens.

[0039] The dumbbell-shaped wood-plastic composite material specimens prepared by using the wood-plastic composite material of the comparative example and the dumbbell-shaped nano-silica / wood-plastic composite material specimens prepared by using the nano-silica / wood-plastic composite material prepared by Examples 1 to 5 were subjected to tensile property testing, and the test method was carried out according to the American Society for Testing and Materials ASTM D638-14 test method standard type 1 for tensile properties of plastics, and the tensile speed was 5 mm / min. The elongation at break, maximum load, elastic modulus and tensile strength test results of the 3D printed test specimens of Examples 1 to 5 and the comparative example are listed in Table 1, and the front surface roughness, back surface roughness and dimensional deformation of the specimens are also listed in Table 1.

[0040] Table 1 Test results of 3D printed test samples of Examples 1 to 5 and Comparative Examples

[0041]

[0042] The relationship between the surface roughness and the content of nano-silicon dioxide in the 3D printed test samples of Examples 1 to 5 and the comparative example is as follows: Figure 2 As shown in the figure, the relationship between the size deformation and the nano-silicon dioxide content is as follows Figure 3 As shown, from Figure 2 It can be seen that with the increase of nano-silica content, the surface roughness of the front and back of the printed specimens shows a downward trend, and the dimensional deformation of the printed specimens also tends to decrease. This is mainly because nano-silica significantly optimizes the uniformity of heat conduction and suppresses surface defects through multi-dimensional synergy. The core mechanism is: First, nanoparticles are evenly dispersed in the polymer melt with ultra-high specific surface area and surface activity, and repair the pores and microcracks between wood powder and the matrix through physical filling and surface diffusion effects, forming a cross-scale three-dimensional continuous heat conduction network, effectively bridging the local thermal resistance caused by the difference in thermal conductivity between wood fiber and plastic matrix, promoting the rapid conduction of heat along the particle chain during sintering, and significantly reducing the unevenness of temperature gradient distribution. Secondly, in the laser energy absorption stage, nanoparticles uniformly convert laser energy into thermal energy through localized surface plasmon resonance effect and light scattering, suppressing the drastic temperature fluctuations caused by local energy enrichment in the molten pool, and at the same time reducing the viscosity by adjusting the rheological properties of the melt, promoting the molten polymer to fully infiltrate the gaps between wood fibers, and reducing the microstructural defects caused by unmelted particles or bubbles. During the cooling and solidification process, the high elastic modulus of the nanoparticles gives the material a higher ability to resist deformation, absorbing part of the thermal stress through elastic energy storage, while the micro-slip behavior at the interface between the particles and the matrix releases residual stress through the friction dissipation mechanism, suppressing the warping and surface fluctuations caused by anisotropic shrinkage. This full-process regulation from energy absorption, melt penetration to thermal stress release ultimately achieves a balanced distribution of the internal thermal-force field of the material, significantly improving the surface flatness and dimensional stability of the sintered parts.

[0043] The relationship between the tensile strength and the nano-silicon dioxide content of the 3D printed test samples of Examples 1 to 5 and the comparative example is as follows: Figure 4 As shown, it can be seen that at low nano-silica content, the tensile strength gradually increases. This is because the nano-silica particles are evenly dispersed in the wood-plastic matrix, filling the voids in the material and enhancing the interfacial bonding force, thereby improving the material's density and mechanical properties. When the nano-silica content reaches about 4.5%, the tensile strength reaches a peak of about 3.15MPa, at which time the dispersion and interfacial bonding of the nanoparticles reach the optimal state and can effectively transfer stress. However, when the nano-silica content exceeds 4.5%, the tensile strength begins to decrease. This is because too many nanoparticles are prone to agglomeration, forming stress concentration points, weakening the interfacial bonding of the material, and resulting in a decrease in mechanical properties.

[0044] The relationship between the maximum load and the nano-silicon dioxide content of the 3D printed test samples of Examples 1 to 5 and the comparative example is as follows: Figure 5 As shown in the figure, it can be seen that with the addition of nano-silica, the maximum load of the composite material increases, indicating that the addition of nanoparticles enhances the strength and stiffness of the material. This enhancement effect is mainly attributed to the high specific surface area and strong interface interaction of nano-silica, which can effectively transfer stress and inhibit crack propagation. In addition, the uniform dispersion of nanoparticles also helps to improve the overall performance of the material, making it more suitable for demanding SLS applications.

[0045] The relationship between the hardness and the content of nano-silicon dioxide of the 3D printed test samples of Examples 1 to 5 and the comparative example is as follows: Figure 6 As shown in the figure, it can be seen that with the increase of nano-silica content, the hardness of the material shows a trend of first increasing and then decreasing. This shows that the right amount of nano-silica can effectively enhance the mechanical properties of wood-plastic composites. The high specific surface area and strong interface interaction of nano-silica enable it to be evenly dispersed in the wood-plastic matrix and enhance the overall structure of the material. However, when the nano-silica content exceeds a certain threshold, it may cause particle agglomeration, thereby reducing the hardness of the material.

[0046] The advantages of the nano-silica / wood-plastic composite material for selective laser sintering of the present invention are reflected in reducing the surface roughness and dimensional deformation of the printed parts: the nano-silica is evenly dispersed in the matrix to form a three-dimensional heat-conducting network, which promotes the uniform conduction of heat during the sintering process and reduces the temperature gradient caused by local thermal resistance differences, thereby effectively inhibiting the surface microcracks and warping deformation caused by thermal stress. At the same time, the nanoparticles optimize the laser energy absorption efficiency by enhancing the melt fluidity and interface bonding force, improve the penetration effect of the molten polymer into the gaps between the wood powder, and reduce unmelted particles and microscopic defects. In addition, the filling effect and interface enhancement of nano-silica synergistically improve the mechanical properties of the composite material, making it have excellent tensile strength, load-bearing capacity and hardness. This material is suitable for SLS molding of high-precision complex structural parts, significantly reducing the need for post-processing and promoting high-quality 3D printing applications.

Claims

1. A method for preparing nano-silicon dioxide / wood-plastic composite materials for selective laser sintering, characterized in that: The method proceeds as follows:

1. Grind the poplar wood into powder and vacuum dry it to obtain dry poplar wood powder; then mix the dried poplar wood powder with sodium hydroxide solution, stir for 20 to 24 hours, let it stand, pour off the upper alkali solution, wash the poplar wood powder with distilled water until the filtrate is neutral, and then dry the poplar wood powder to obtain alkali-treated poplar wood powder; 2. Mix anhydrous ethanol and distilled water in a mass ratio of (2.5-3.5):1 to obtain an ethanol solution; add HCl aqueous solution to the ethanol solution to adjust the pH of the solution to 3.5-4.5, then add alkali-treated poplar wood powder and silane coupling agent KH550 and mix them evenly, let stand at room temperature for 10-30 minutes, transfer to a three-necked flask for water bath reflux treatment, the reflux temperature is 82-88°C, and the reaction time is 4-5h; after the reflux is completed, let stand and pour out the upper liquid, remove the solution by vacuum filtration, wash the poplar wood powder with ethanol until the filtrate is neutral, and finally dry the poplar wood powder at a temperature of 60-65°C, and then heat it to 100-105°C for aging until the water content of the wood powder by mass reaches less than 2%, to obtain the poplar wood powder treated with the silane coupling agent KH550; 3. Weigh 72% to 81% of pure polyethersulfone powder, 8% to 12% of poplar wood powder treated with KH550, 4.5% to 5.5% of calcium carbonate, 3% to 6% of nano-silicon dioxide powder, and 3.5% to 4.5% of lubricant glycerol according to mass percentage, add them into a blender and mix evenly, then seal and let stand for 20 to 24 hours to obtain a nano-silicon dioxide / wood-plastic composite material for selective laser sintering.

2. The method for preparing a nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 1, characterized in that: The vacuum drying described in step 1 is vacuum drying at a temperature of 80° C. for 24 hours.

3. The method for preparing a nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 1 or 2, characterized in that: The drying described in step 1 is carried out at a temperature of 80° C. for 24 hours.

4. The method for preparing a nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 1 or 2, characterized in that: The pure polyethersulfone powder described in step 3 has a fineness of 150 μm to 250 μm.

5. The method for preparing a nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 1 or 2, characterized in that: The fineness of the calcium carbonate described in step 3 is 30 μm to 60 μm; the purity in terms of mass percentage is greater than 99.0%.

6. The method for preparing a nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 1 or 2, characterized in that: The average particle size of the nano silicon dioxide powder described in step three is 300nm to 350nm.

7. Application of the nano-silicon dioxide / wood-plastic composite material for selective laser sintering prepared by the method of claim 1, characterized in that: The application is to 3D print nano-silica / wood-plastic composites through selective laser sintering technology.

8. The use of nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 7, characterized in that: The specific steps of 3D printing nano-silica / wood-plastic composite materials through selective laser sintering technology are: create a model file of the part to be 3D printed through modeling software, then import the model into slicing software, set printing parameters, and the slicing software will layer the model, generate the printing path of each layer, and output it as a G-code file, which is an instruction set for controlling the movement of the printer; then transmit the G-code to the 3D printer, evenly place the nano-silica / wood-plastic composite material into the hopper of the selective laser sintering printer, and before starting printing, preheat the printer to the set temperature, and then scan and print layer by layer to obtain the nano-silica / wood-plastic composite material parts.

9. The use of the nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 8, characterized in that: The preheat setting temperature is 85°C.

10. The use of the nano-silicon dioxide / wood-plastic composite material for selective laser sintering according to claim 8, characterized in that: The scanning speed is 2000 when scanning layer by layer.

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