Optical system, additive manufacturing system and laser 3D printing method

Abstract

This invention provides an optical system, an additive manufacturing system, and a laser 3D printing method. A laser source emits laser light; a polarizer divides the laser light into vertically polarized light and parallelly polarized light; a half-wave plate rotates the polarization direction of the vertically polarized light by 180° to match the polarization direction of a silicon-based liquid crystal chip; a first reflector reflects the vertically polarized light to adjust the incident angle of the vertically polarized light entering the silicon-based liquid crystal chip; the silicon-based liquid crystal chip rearranges the intensity of the vertically polarized light spot; a second reflector merges the vertically polarized light and parallelly polarized light into a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat the powder. Using a silicon-based liquid crystal chip as the core component for area laser 3D printing can improve printing efficiency; merging the vertically polarized light and parallelly polarized light into a target laser can improve energy utilization.

Description

Technical Field

[0001] This invention relates to the field of laser printing technology, and in particular to an optical system, an additive manufacturing system, and a laser 3D printing method. Background Technology

[0002] Currently, laser metal additive manufacturing technology is gradually moving from prototype verification in the R&D stage to large-scale mass production and functional component integration in consumer electronics products. In laser powder bed fusion (LPBF) based metal additive manufacturing, laser metal additive manufacturing (LAM) achieves the shaping of complex components through layer-by-layer melting and solidification. However, layer-by-layer additive manufacturing inherently has some bottlenecks: build volume and build speed. In typical metal additive manufacturing galvanometer-field lens optical systems, the build volume is limited by the finite area of ​​the scanning system, while build speed and build accuracy (mainly related to the focused spot) are difficult to balance simultaneously. Currently, the mainstream technical solution for laser metal additive manufacturing mainly adopts increasing the number of lasers to improve printing efficiency. In principle, this can multiply laser printing efficiency, but it also increases the complexity of the printing equipment and manufacturing costs. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide an optical system, an additive manufacturing system, and a laser 3D printing method to reduce laser loss while avoiding the need for additional waste light collection devices and improving energy utilization.

[0004] In a first aspect, embodiments of the present invention provide an optical system for laser additive manufacturing. The optical system includes: a laser source, a polarizer, a half-wave plate, a first reflector, a silicon-based liquid crystal chip, and a second reflector. The laser source is used to emit laser light. The polarizer is used to divide the laser light into vertically polarized light and parallelly polarized light. The half-wave plate is used to rotate the polarization direction of the vertically polarized light by 180° so that the vertically polarized light matches the polarization direction of the silicon-based liquid crystal chip. The first reflector is used to reflect the vertically polarized light to adjust the incident angle of the vertically polarized light entering the silicon-based liquid crystal chip. The silicon-based liquid crystal chip is used to rearrange the intensity of the vertically polarized light spot. The second reflector is used to merge the vertically polarized light and the parallelly polarized light into a target laser. The vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat powder.

[0005] In an optional embodiment of this application, the optical system further includes a collimator; the collimator is used to collimate the laser emitted by the laser source to reduce the divergence angle of the laser.

[0006] In an optional embodiment of this application, the optical system further includes: a plurality of laser lenses; the plurality of laser lenses are used to collimate and expand the laser emitted by the collimator to reduce the divergence angle of the laser.

[0007] In an optional embodiment of this application, the aforementioned silicon-based liquid crystal chip is connected to an external computer; the silicon-based liquid crystal chip is used to rearrange liquid crystal molecules based on computer-based image control, so as to produce differences in refractive index at different pixels and rearrange the intensity of the vertically polarized light spot.

[0008] In an optional embodiment of this application, the optical system further includes: a first laser lens and a second laser lens, the first laser lens and the second laser lens having the same focal length; the silicon-based liquid crystal chip and the first laser lens are positioned at a distance equal to the focal length, the first laser lens and the second laser lens are positioned at a distance equal to twice the focal length, and the second laser lens and the external powder bed are positioned at a distance equal to the focal length; the first laser lens is used to perform Fourier transform on the target laser; the second laser lens is used to perform inverse Fourier transform on the target laser; and the powder bed is used to present a laser pattern based on the target laser.

[0009] Secondly, embodiments of the present invention also provide an additive manufacturing system, comprising: the aforementioned optical system, powder bed, and forming cylinder; the optical system is used to emit a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat the powder; the powder bed is used to perform full-layer selective melting based on the target laser; and the forming cylinder is used to descend by one layer thickness after the current layer is formed.

[0010] In optional embodiments of this application, the additive manufacturing system further includes a powder spreading mechanism, a forming cylinder, and an optical system housed within an argon-protected glove box.

[0011] In an optional embodiment of this application, the additive manufacturing system further includes: a computer connected to a silicon-based liquid crystal chip of an optical system; the computer is used to rearrange the liquid crystal molecules of the silicon-based liquid crystal chip based on an image control method.

[0012] Thirdly, embodiments of the present invention also provide a laser 3D printing method applied to the above-mentioned additive manufacturing system. The laser 3D printing method includes: introducing an inert gas; importing a 3D model of the part and slicing the 3D model into layers according to a set layer thickness; dividing the outline of each slice into sub-regions to generate corresponding different image control modes; controlling the forming cylinder to descend by one layer thickness and setting the powder layer thickness; controlling the powder spreading mechanism to uniformly spread metal powder on the forming substrate based on the powder layer thickness; controlling the silicon-based liquid crystal chip of the optical system based on the image control mode of the current layer to project the target laser regulated by the optical system onto the powder bed to complete the whole-layer selective melting of the current layer; after the current layer is formed, controlling the forming cylinder to descend by one layer thickness and the powder spreading mechanism to spread powder again; switching the image control mode of the current layer to the image control mode of the next layer until the part is formed.

[0013] In an optional embodiment of this application, after the silicon-based liquid crystal chip that controls the optical system based on the image control method of the current layer projects the target laser after the optical system is regulated onto the powder bed and completes the whole-layer selective melting of the current layer, the method further includes: when the part size is larger than the single-field forming size, performing image stitching.

[0014] The embodiments of the present invention bring the following beneficial effects: This invention provides an optical system, an additive manufacturing system, and a laser 3D printing method. A laser source emits laser light; a polarizer divides the laser light into vertically polarized and parallelly polarized light; a half-wave plate rotates the polarization direction of the vertically polarized light by 180° to match the polarization direction of a silicon-based liquid crystal chip; a first reflector reflects the vertically polarized light to adjust the incident angle of the vertically polarized light entering the silicon-based liquid crystal chip; the silicon-based liquid crystal chip rearranges the intensity of the vertically polarized light spot; and a second reflector merges the vertically polarized and parallelly polarized light into a target laser. The vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat the powder. In this method, using a silicon-based liquid crystal chip as the core component for regional laser 3D printing can achieve micron-level forming accuracy and improve printing efficiency. Merging the vertically polarized and parallelly polarized light into a target laser reduces laser loss and avoids the need for additional waste light collection devices, thus improving energy utilization.

[0015] Other features and advantages of this disclosure will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the techniques described above.

[0016] To make the above-mentioned objects, features and advantages of this disclosure more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of an optical system provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an additive manufacturing system provided in an embodiment of the present invention; Figure 3 A flowchart of a laser 3D printing method provided in an embodiment of the present invention.

[0019] Icons: 101-Laser source; 102-Collimator; 103-Third laser lens; 104-Fourth laser lens; 105-Polarizer; 106-Half-wave plate; 107-First reflector; 108-Silicon-based liquid crystal chip; 109-Second reflector; 110-First laser lens; 111-Second laser lens; 112-Powder bed; 113-Forming cylinder; 114-Optical system; 115-Computer; 116-Additive manufacturing system. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Currently, numerous research institutions and companies are conducting research on area laser 3D printing technology, with high-damage-threshold projection devices as the core component, using various technical approaches. Theoretically, it can simultaneously print areas consisting of hundreds of thousands or even millions of pixels, balancing printing efficiency and accuracy, demonstrating its enormous potential for improving 3D printing efficiency. Most area laser 3D printing technologies are essentially high-power laser projections, and metal processing requires extremely high laser power density. Therefore, the optical components that perform the "projection" function need to withstand extremely high power density. Thus, the technical bottleneck of area laser 3D printing technology lies in the high-damage-threshold projection element, while also requiring high energy utilization efficiency. Currently, devices such as High-Damage-Threshold Digital Micromirror Devices (DMDs) and Optically Addressed Light Valves (OALVs) have seen some meaningful research in metal 3D printing; however, due to the limitations of their projection principles, they suffer from significant energy loss. Liquid crystal on silicon (Lcos) has relatively low energy loss during projection and can withstand high power, meeting the requirements for a core component of area laser 3D printing technology.

[0022] Based on this, the embodiments of the present invention provide an optical system, an additive manufacturing system, and a laser 3D printing method, specifically providing a high-efficiency, high-energy-utilization regional laser 3D printing technology with Lcos as the core component, while also possessing high forming accuracy.

[0023] To facilitate understanding of this embodiment, an optical system disclosed in this embodiment of the invention will first be described in detail.

[0024] Example 1: This invention provides an optical system for laser additive manufacturing. Laser light is essentially an electromagnetic wave, and its intensity at a given point can be represented by the product of amplitude and phase. E(x,y)=A(x,y)×exp[j×θ(x,y)]; Where E(x,y) is the laser intensity at a certain location, A(x,y) is the laser amplitude at a certain location, and exp[j×θ(x,y)] is the laser phase at a certain location.

[0025] Current projection methods can be understood as modulating the intensity at a specific point through optical devices, i.e., modulating the amplitude or phase. DMD and OALV projection methods use amplitude modulation, which involves blocking or reflecting light at corresponding pixels to achieve a single exposure and form a specific pattern, resulting in significant energy loss. Lcos, on the other hand, is essentially a phase modulation (typically achieved through single-lens focusing, which rearranges energy in the spatial domain with minimal energy loss). The rearrangement of liquid crystal molecules leads to differences in refractive index at different pixels, thus rearranging the intensity of the emitted light spot. Therefore, energy loss is relatively small, and the overall light energy utilization rate is approximately 80%, while the light energy utilization rate of DMD and OALV projection methods is generally below 50%.

[0026] Based on the above description, see Figure 1 The diagram shows the structure of an optical system 114, which includes: a laser source 101, a polarizer 105, a half-wave plate 106, a first reflector 107, a silicon-based liquid crystal chip 108, and a second reflector 109.

[0027] like Figure 1 As shown, the laser source 101 is used to emit laser light. The laser source in this embodiment includes, but is not limited to, fiber lasers, laser diode arrays, solid-state lasers, etc., with an average power exceeding several hundred watts.

[0028] like Figure 1 As shown, the optical system 114 also includes a collimator 102; the collimator 102 is used to collimate the laser emitted by the laser source 101 in order to reduce the divergence angle of the laser.

[0029] In this embodiment, the laser source 101 and collimator 102 can form a standard light source device. The laser emitted from the laser source 101 has a smaller divergence angle after being collimated by the collimator 102, which facilitates subsequent shaping.

[0030] In some embodiments, the optical system 114 further includes: a plurality of laser lenses; the plurality of laser lenses are used to collimate and expand the laser emitted by the collimator to reduce the divergence angle of the laser.

[0031] like Figure 1 As shown, the optical system 114 also includes a third laser lens 103 and a fourth laser lens 104, which together collimate and expand the beam, further reducing the divergence angle, and ensuring that the laser spot meets the requirements of the subsequent optical path.

[0032] like Figure 1 As shown, polarizer 105 is used to divide laser light into vertically polarized light and parallelly polarized light.

[0033] In this embodiment, the polarizer 105 can be a 45-degree polarization beam splitter, which can further divide a laser beam into two orthogonal polarization channels: vertically polarized light (s-beam) and parallelly polarized light (p-beam).

[0034] like Figure 1 As shown, the half-wave plate 106 is used to rotate the polarization direction of vertically polarized light by 180° so that the vertically polarized light matches the polarization direction of the silicon-based liquid crystal chip 108.

[0035] In this embodiment, the half-wave plate 106 can rotate 180° to change the polarization direction of the s-light transmitted through the polarizer 105 without changing the polarization type of the light, which facilitates matching the polarization direction of the subsequent Lcos chip.

[0036] like Figure 1 As shown, the first reflector 107 is used to reflect vertically polarized light in order to adjust the incident angle of vertically polarized light entering the silicon-based liquid crystal chip 108.

[0037] In this embodiment, the first reflector 107 can be a 45° reflector. After passing through the first reflector 107, the S-light enters the Lcos chip at a small angle (e.g., 10°).

[0038] like Figure 1 As shown, the silicon-based liquid crystal chip 108 is used to rearrange the intensity of the light spot of vertically polarized light.

[0039] The Lcos chip in this embodiment can have more than a million pixels, each pixel being approximately 10×10 micrometers in size, and can withstand an average incident laser power of approximately several hundred watts or even several kilowatts.

[0040] like Figure 1 As shown, the silicon-based liquid crystal chip 108 is connected to an external computer 115; the silicon-based liquid crystal chip 108 is used to rearrange liquid crystal molecules based on the image control method of the computer 115, so that the refractive index at different pixels is different, and the intensity of the spot of vertically polarized light is rearranged.

[0041] This embodiment can input different image control algorithms through an external computer to rearrange the liquid crystal molecules, resulting in differences in refractive index at different pixels, thereby achieving a rearrangement of the intensity of the emitted light spot, in fact producing different patterns, achieving an effect similar to laser projection.

[0042] like Figure 1 As shown, the second reflector 109 is used to combine vertically polarized light and parallelly polarized light into a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used for heating / preheating powder.

[0043] In this embodiment, the second reflector 109 can be a 45° reflector. After being reflected by the second reflector 109, the p-beam is combined with the s-beam diffracted by the Lcos chip to form a single laser beam, which can be called the target laser. The p-beam can be used to heat the powder, and the s-beam can be used for laser printing, achieving efficient utilization of most of the energy, reducing laser loss, and avoiding the need for additional waste light collection devices.

[0044] like Figure 1 As shown, the optical system 114 also includes: a first laser lens 110 and a second laser lens 111, wherein the focal length F of the first laser lens 110 and the second laser lens 111 is the same. The silicon-based liquid crystal chip 108 and the first laser lens 110 are positioned at a distance equal to the focal length F. The first laser lens 110 and the second laser lens 111 are positioned at a distance equal to twice the focal length F. The second laser lens 111 and the external powder bed 112 are positioned at a distance equal to the focal length F. The first laser lens 110 is used to perform Fourier transform on the target laser. The second laser lens 111 is used to perform inverse Fourier transform on the target laser. The powder bed 112 is used to present a laser pattern based on the target laser.

[0045] In this embodiment, the silicon-based liquid crystal chip 108, the first laser lens 110, the second laser lens 111, and the powder bed 112 can form a "4F" system, which allows the laser pattern modulated by the silicon-based liquid crystal chip 108 to be perfectly displayed on the surface of the powder bed 112. The accuracy of the forming surface is equal to the pixel accuracy of the Lcos chip, which can be within 10 micrometers, which is much better than the accuracy of traditional metal 3D printing technology.

[0046] This invention provides an optical system in which a laser source emits laser light; a polarizer divides the laser light into vertically polarized light and parallelly polarized light; a half-wave plate rotates the polarization direction of the vertically polarized light by 180° to match the polarization direction of the vertically polarized light with that of a silicon-based liquid crystal chip; a first reflector reflects the vertically polarized light to adjust the incident angle of the vertically polarized light entering the silicon-based liquid crystal chip; the silicon-based liquid crystal chip rearranges the intensity of the vertically polarized light spot; and a second reflector merges the vertically polarized light and parallelly polarized light into a target laser. The vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat powder. In this method, using a silicon-based liquid crystal chip as the core component for regional laser 3D printing can achieve micron-level forming accuracy and improve printing efficiency; merging the vertically polarized light and parallelly polarized light into a target laser reduces laser loss and avoids the need for additional waste light collection devices, thus improving energy utilization.

[0047] Example 2: This invention provides an additive manufacturing system, implemented based on the aforementioned embodiments, see below. Figure 2The diagram shows a structural schematic of an additive manufacturing system 116, which includes: an optical system 114, a powder bed 112, and a forming cylinder 113 as provided in the aforementioned embodiments; the optical system 114 is used to emit a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat / preheat the powder; the powder bed 112 is used to complete the selective melting of the entire layer based on the target laser; the forming cylinder 113 is used to descend by one layer thickness after the current layer is formed.

[0048] In some embodiments, the additive manufacturing system also includes a powder spreading mechanism, a forming cylinder, and an optical system. The entire additive manufacturing system can be placed in an inert gas protective atmosphere, such as in an argon-protected glove box, through which ultra-high purity inert gas is introduced to reduce the oxygen content to below 500 ppm.

[0049] In this embodiment, the powder bed is a thin-layer structure used in metal additive manufacturing to hold and melt metal powder. The forming cylinder is a mechanical chamber that houses the powder bed and controls its vertical movement. The forming cylinder contains a liftable build platform. After each layer is printed, the platform descends by one layer thickness (typically 20–100 μm), and then a powder spreading mechanism spreads new metal powder onto the surface, forming a new powder bed layer. This process is repeated until the part is fully formed.

[0050] like Figure 2 As shown, the additive manufacturing system also includes: a computer 115, which is connected to the silicon-based liquid crystal chip of the optical system; the computer is used to rearrange the liquid crystal molecules of the silicon-based liquid crystal chip based on image control.

[0051] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the additive manufacturing system described above can be referred to the corresponding process in the aforementioned optical system embodiments, and will not be repeated here.

[0052] Example 3: This invention provides a laser 3D printing method, implemented based on the foregoing embodiments, and applied to the additive manufacturing system provided in the foregoing embodiments. See [link to relevant documentation]. Figure 3 The flowchart shown illustrates a laser 3D printing method, which includes the following steps: Step S302: Inert gas is introduced.

[0053] This embodiment allows for system and environmental preparation: the powder spreading mechanism, forming cylinder, and optical system are placed inside an argon-protected glove box, and ultra-high purity inert gas is introduced into the additive manufacturing system to reduce the oxygen content to below 500 ppm.

[0054] Step S304: Import the 3D model of the part, and slice the 3D model into layers according to the set layer thickness; divide the outline of each slice into sub-region blocks to generate corresponding different image control methods.

[0055] This embodiment can perform model slicing and Lcos control algorithm generation: Import the 3D model of the part, which can be in STL (Stereolithography) format, and slice it into layers according to a set layer thickness (e.g., 30-100μm). Divide the outline of each slice into sub-regions to generate corresponding different control algorithms for Lcos light field modulation.

[0056] Step S306: Control the molding cylinder to descend by one layer thickness and set the powder layer thickness; control the powder spreading mechanism to uniformly spread metal powder on the molding substrate based on the powder layer thickness.

[0057] This embodiment can perform powder spreading and substrate pretreatment: the forming cylinder descends by one layer thickness and sets the powder spreading layer thickness; the powder spreading mechanism spreads metal powder (such as tin powder, 316L stainless steel powder) evenly on the forming substrate at low speed; if necessary, multiple re-spreading processes can be used to improve the uniformity of the layer thickness and reduce powder drag marks.

[0058] The method provided in this embodiment is applicable not only to metal powders, but also to most additive manufacturing powders, such as nylon powders.

[0059] Step S308: Based on the image control method of the current layer, control the silicon-based liquid crystal chip of the optical system, project the target laser after the optical system is regulated onto the powder bed, and complete the whole-layer selective melting of the current layer.

[0060] This embodiment can perform regional laser projection molding: the light field controlled by Lcos is projected onto the preheated powder bed through the imaging lens group, and the entire layer of selective melting is completed in one go.

[0061] In some embodiments, image stitching can also be performed when the part size is larger than the single-stage molding size.

[0062] This embodiment can also perform image stitching for large-size parts (when exceeding the range of a single field): when the part size is larger than the single-field forming size (Lcos projected area on the powder bed), the image stitching algorithm is activated. The optical system can be fixed on the gantry, and the travel in both horizontal directions meets the maximum printing area; a 100μm overlap area is set between sub-regions to ensure the intra-layer connection strength and forming continuity.

[0063] Step S310: After the current layer is formed, control the forming cylinder to descend by one layer thickness, and the powder spreading mechanism to spread powder again; switch the image control mode of the current layer to the image control mode of the next layer until the part is formed.

[0064] This embodiment can perform interlayer cycling and layer-by-layer stacking: after the current layer is formed, the forming cylinder descends by one layer thickness, and the powder spreading mechanism re-spreads the powder; switch to the next layer slicing Lcos control algorithm, repeat the powder spreading → regional laser projection forming → image stitching steps; cycle layer by layer until the entire part is completely formed.

[0065] This embodiment can also perform post-molding processing: the workpiece is cooled to room temperature along with the substrate under a protective atmosphere; the molding cylinder is lifted and the substrate and molded part are removed; unmelted powder is removed, and the part is peeled off and post-processed.

[0066] The method provided in this invention proposes a regional laser 3D printing technology with Lcos as the core component, achieving micron-level forming accuracy. Through optical system design, compared to using only the s-beam from the Lcos chip, which has a light energy utilization rate of only 40% (due to 20% diffraction loss at the Lcos chip), this embodiment can choose to reflect the p-beam back and combine it with the s-beam passing through the Lcos chip to form the target laser, achieving an energy utilization rate of up to 80%, which is superior to most previously proposed regional laser printing technologies. A single exposure can reach millions of laser units, greatly improving the efficiency of current single-point scanning metal 3D printing and meeting the growing demand for mass production and functional component integration in consumer electronics.

[0067] In summary, the optical system, additive manufacturing system, and laser 3D printing method described in the embodiments of the present invention mainly provide the following: 1. A regional laser 3D printing technology with Lcos as the core component is proposed, which has micron-level forming accuracy and can improve printing efficiency. Through regional laser projection, millions of pixels can be projected at once, with pixel accuracy below 10 micrometers.

[0068] 2. An optical system is provided that can combine p-beams and s-beams, thereby improving energy utilization. Energy that cannot be utilized by the Lcos beam is reused through optical path design to heat the powder surface, achieving the predetermined temperature for metal powder printing; this reduces laser loss while avoiding the need for additional waste light collection devices, thus improving energy utilization.

[0069] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the laser 3D printing method described above can be referred to the corresponding process in the foregoing embodiments, and will not be repeated here.

[0070] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0071] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0072] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0073] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An optical system characterized by comprising: For use in laser additive manufacturing, the optical system includes: a laser source, a polarizer, a half-wave plate, a first reflector, a silicon-based liquid crystal chip, and a second reflector; The laser source is used to emit laser light; The polarizer is used to divide the laser light into vertically polarized light and parallelly polarized light; The half-wave plate is used to rotate the polarization direction of the vertically polarized light by 180° so that the vertically polarized light matches the polarization direction of the silicon-based liquid crystal chip. The first reflector is used to reflect the vertically polarized light to adjust the incident angle of the vertically polarized light entering the silicon-based liquid crystal chip; The silicon-based liquid crystal chip is used to rearrange the intensity of the vertically polarized light spot; The second reflector is used to combine vertically polarized light and parallelly polarized light into a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat powder.

2. The optical system according to claim 1, characterized in that, The optical system also includes: a collimator; The collimator is used to collimate the laser emitted by the laser source in order to reduce the laser divergence angle.

3. The optical system according to claim 2, characterized in that, The optical system also includes: multiple laser lenses; Multiple laser lenses are used to collimate and expand the laser emitted by the collimator to reduce the laser divergence angle.

4. The optical system according to claim 1, characterized in that, The silicon-based liquid crystal chip is connected to an external computer; The silicon-based liquid crystal chip is used to rearrange liquid crystal molecules based on the image control method of the computer, so as to produce differences in refractive index at different pixels, and to rearrange the intensity of the vertically polarized light spot.

5. The optical system according to claim 1, characterized in that, The optical system further includes: a first laser lens and a second laser lens, wherein the first laser lens and the second laser lens have the same focal length; The placement distance between the silicon-based liquid crystal chip and the first laser lens is the focal length; the placement distance between the first laser lens and the second laser lens is twice the focal length; and the placement distance between the second laser lens and the external powder bed is the focal length. The first laser lens is used to perform a Fourier transform on the target laser; The second laser lens is used to perform an inverse Fourier transform on the target laser; The powder bed is used to generate a laser pattern based on the target laser.

6. An additive manufacturing system, characterized in that, The additive manufacturing system includes: the optical system, powder bed, and forming cylinder as described in any one of claims 1-5; The optical system is used to emit a target laser; wherein, the vertically polarized light of the target laser is used for laser printing, and the parallelly polarized light of the target laser is used to heat the powder; The powder bed is used to perform full-layer selective melting based on the target laser; The forming cylinder is used to lower the current layer by one layer thickness after the current layer has been formed.

7. The additive manufacturing system according to claim 6, characterized in that, The additive manufacturing system further includes a powder spreading mechanism, the powder spreading mechanism, the forming cylinder, and the optical system, all housed within an argon-protected glove box.

8. The additive manufacturing system according to claim 6, characterized in that, The additive manufacturing system further includes a computer, which is connected to the silicon-based liquid crystal chip of the optical system. The computer is used to rearrange the liquid crystal molecules of the silicon-based liquid crystal chip based on an image control method.

9. A laser 3D printing method, characterized in that, The laser 3D printing method, applied to the additive manufacturing system according to any one of claims 6-8, comprises: Inert gas is introduced; Import the 3D model of the part, and slice the 3D model into layers according to the set layer thickness; divide the outline of each slice into sub-regions to generate different corresponding image control methods. The molding cylinder is controlled to descend by one layer thickness, and the powder layer thickness is set; the powder spreading mechanism is controlled to uniformly spread metal powder on the molding substrate based on the powder layer thickness. Based on the image control method of the current layer, the silicon-based liquid crystal chip of the optical system is controlled to project the target laser after the optical system is regulated onto the powder bed to complete the whole layer selective melting of the current layer. After the current layer is formed, the forming cylinder is lowered by one layer thickness, and the powder spreading mechanism spreads powder again; the image control mode of the current layer is switched to the image control mode of the next layer until the part is formed.

10. The laser 3D printing method according to claim 9, characterized in that, Based on the image control method of the current layer, the silicon-based liquid crystal chip of the optical system is controlled to project the target laser after optical system modulation onto the powder bed. After completing the step of whole-layer selective melting of the current layer, the method further includes: When the size of the part is larger than the size of a single molding process, image stitching is performed.

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