A gray scale control realizes gradient mechanical structure of light-cured micro-nano 3D printing equipment and printing method

Abstract

The application discloses a kind of gray scale control to realize gradient mechanical structure's photocuring micro-nano 3D printing equipment and printing method, including base, light machine module, printing platform and material tank, light machine module is set on the horizontal section of L column, including adjustable light machine I, adjustable light machine II and adjustable light machine III arranged along y direction array, material tank is arranged on base and opening is arranged upwards, material tank can rotate around vertical center rotating shaft and is adjusted along x direction, y direction and z direction, printing platform is arranged in material tank, and printing platform includes workbench, U-shaped block and connecting block, workbench can be adjusted by lifting and tilting, light machine module is slidably arranged on y direction guide rail and is drivenly connected with y' direction adjusting mechanism, to carry out the switching of adjustable light machine I, adjustable light machine II and adjustable light machine III, different gray value light switching can be realized to carry out gray printing, and the structure with different gradient mechanical properties or the support structure that is more easily removed is obtained.

Description

Technical Field

[0001] This invention belongs to the field of photopolymer micro-nano 3D printing technology, and in particular provides a photopolymer micro-nano 3D printing device and printing method for achieving gradient mechanical structures by grayscale control. Background Technology

[0002] Additive manufacturing ("3D printing") is a relatively new manufacturing technology that has gained popularity in recent years. It uses a three-dimensional digital model as a basis to create three-dimensional solids by layering and stacking materials. Additive manufacturing technology has fundamentally broken through the technical bottleneck of complex and irregularly shaped components, enabling the controllable shaping of the microstructure and macrostructure of materials.

[0003] Photopolymerization rapid prototyping technology is currently the most widely used 3D printing technology. This technology uses photosensitive resin liquid as raw material; the photosensitive properties of the resin cause the material to undergo a polymerization reaction and solidify when exposed to light of a specific wavelength. With the rapid development of photopolymerization 3D printing and micro / nano technology, micro / nano-scale 3D printing technology has been developed and applied to various fields and industries.

[0004] Currently, most photopolymer 3D micro-nano printing methods employ axial movement and layer-by-layer exposure printing. Photopolymer 3D printing equipment using digital micro-mirror device (DMD) chips can easily change the printed pattern by modifying parameters. However, it suffers from high cost and low resolution, and also faces the following technical problems: 1) The optical engine exposes the printed part through a centrifugal membrane from bottom to top. The working platform needs to overcome the adhesion between the printed part and the release film for demolding, which easily leads to unsuccessful demolding or printing defects at the micro-nano scale; 2) Manual removal of printing supports at the micro-nano scale can easily damage the printed parts, and not using supports will lead to printing defects; 3) It is impossible to achieve gradient or localized enhanced exposure to achieve better structural mechanical properties. Defects such as stress concentration, cracking, and peeling occur during the use of single mechanical structures, resulting in functional parts with high weight and undesirable structural mechanical properties. Summary of the Invention

[0005] Based on this, the present invention provides a photopolymerization micro-nano 3D printing device and method for achieving gradient mechanical structures by grayscale modulation, so as to achieve grayscale printing by switching light with different grayscale values, thereby obtaining structures with different gradient mechanical properties and support structures that are easier to remove, and realizing gradient mechanical property structures or locally reinforced mechanical structures to manufacture lighter, stronger and more environmentally friendly functional parts.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a photopolymerization micro / nano 3D printing device for realizing gradient mechanical structures through grayscale modulation, comprising a base, an optomechanical module, a printing platform, and a material tank.

[0007] An inverted L-shaped column is provided on the base, and the optical engine module is located on the horizontal section extending along the y-direction of the L-shaped column. The optical engine module includes tunable optical engine I, tunable optical engine II, and tunable optical engine III arranged in an array along the y-direction. The tunable optical engine I, tunable optical engine II, and tunable optical engine III cover grayscale values ​​in different ranges from 0 to 255.

[0008] The material trough is mounted on the base with its opening facing upwards. A connecting plate is provided between the base and the material trough. The connecting plate is equipped with a rotary device for driving the material trough to rotate around a vertical central axis. An x-axis adjustment mechanism, a y-axis adjustment mechanism, and a z-axis adjustment mechanism are provided between the base and the connecting plate. The x-axis adjustment mechanism is used to drive the material trough to adjust its position along the x-axis. The y-axis adjustment mechanism is used to drive the material trough to adjust its position along the y-axis. The z-axis adjustment mechanism is used to drive the material trough to adjust its position along the z-axis, thereby adjusting the distance from the liquid surface in the material trough to the optomechanical module and achieving focusing adjustment.

[0009] The printing platform is set inside the material trough and includes a worktable, a U-shaped block, and a connecting block. The worktable is connected to the connecting block via the U-shaped block, and the connecting block is driven by a lifting mechanism to move the worktable from top to bottom, thereby achieving a layer-by-layer printing process. Surface or point printing is achieved based on the surface mask projection or point mask projection of dimmer I, dimmer II, and dimmer III. The U-shaped block is driven by a control servo motor to rotate, thereby causing the worktable to tilt relative to the material trough. In conjunction with multi-axis linkage, curved surface printing is achieved.

[0010] The horizontal section of the L-column is provided with a y-guide rail. The optical engine module is slidably mounted on the y-guide rail and driven and connected to the y'-direction adjustment mechanism. The y'-direction adjustment mechanism is used to drive the optical engine module to move along the y-direction to switch between adjustable optical engine I, adjustable optical engine II and adjustable optical engine III, realize the switching of light with different gray values ​​to perform grayscale printing, and obtain structures with different gradient mechanical properties and support structures that are easier to remove.

[0011] Optionally, the tunable optical generator I, tunable optical generator II, and tunable optical generator III each include a tunable laser, a beam corrector, an energy controller, a beam shape setter, a light shield, an energy detector, a grayscale film, a mask, and an objective lens. The tunable laser emits a laser beam of a specific wavelength as a light source. The beam corrector corrects the incident direction of the laser beam, ensuring it is as parallel as possible. The energy controller controls the energy ultimately incident on the silicon wafer; underexposure or overexposure severely affects image quality. The beam shape setter sets the beam to different shapes such as circular or annular, each with different optical characteristics. The energy detector detects whether the final incident energy of the beam meets the exposure requirements and provides feedback to the energy controller for adjustment. The grayscale film has a certain reflectivity and is used to adjust the grayscale of the model. The mask is a patterned glass plate used to form an optical image. The objective lens compensates for optical errors and scales down the circuit diagram proportionally.

[0012] Optionally, the different reflectivity of the grayscale film can form 11 levels of grayscale variation in the range of 0-10, with the highest grayscale being pure black and the lowest grayscale being pure white, so as to facilitate the model support for grayscale printing as needed.

[0013] Optionally, the mask is a photolithography mask, and the precision of the mask is at the submicron or nanometer level.

[0014] Optionally, the y' adjustment mechanism includes a lead screw and a stepper motor. The lead screw is arranged along the y guide rail, the optomechanical module is threadedly engaged with the lead screw, and the stepper motor is connected to the lead screw via a coupling.

[0015] Optionally, the printing platform is fixedly connected to the material trough via a threaded flange, and the material trough is fixedly connected to the rotary device, forming an integrated unit with the printing platform, material trough, and rotary device.

[0016] Optionally, the rotary device includes a rotary support, a connecting flange, and a stepper motor. The rotary support is fixedly connected to the material trough, the connecting flange is fixedly connected to the rotary support, and the stepper motor is driven to rotate the connecting flange, thereby driving the printing platform and the material trough to rotate.

[0017] Optionally, the worktable is fixedly connected to the U-shaped block, the U-shaped block is fixedly connected to the rotation axis of the control servo motor, the base of the control servo motor is fixedly connected to the connecting block and the lead screw of the lead screw motor, the lead screw motor is used to drive the connecting block to move up and down, and the control servo motor is used to drive the rotation of the U-shaped block to realize the tilting movement of the worktable relative to the material trough, in conjunction with multi-axis linkage, to complete the curved surface printing.

[0018] Optionally, the connecting plate is fixedly connected to the y-axis lead screw slide, the y-axis motor drives the y-axis lead screw slide to slide the connecting plate in the y-axis direction, the x-axis motor drives the x-axis lead screw slide to move the y-axis lead screw slide in the x-axis direction, the base of the x-axis lead screw slide is fixedly connected to the guide rail frame, and the z-axis motor drives the z-axis lead screw slide to slide the guide rail frame up and down, adjusting the distance from the liquid surface of the material tank to the optical engine, thereby achieving high-precision optical engine focusing adjustment.

[0019] To achieve the above objectives, in a second aspect, the present invention provides a photopolymerization micro / nano 3D printing method for realizing gradient mechanical structures through grayscale modulation, comprising:

[0020] Select a suitable liquid resin material and place it into the material tank;

[0021] The first layer of 3D printing of the model: The control table starts from the origin of the reference coordinates and moves along the y-axis, x-axis, and z-axis and tilts at a certain angle according to the set path to achieve multi-axis linkage. When the optical engine module emits light, the liquid resin material that is illuminated by the light quickly solidifies, while the liquid resin material that is not illuminated by the light remains in its original state until the first layer of 3D printing of the model is completed.

[0022] After the first layer of 3D printing of the model is completed, the workbench descends one layer according to the set height to start the second layer of 3D printing, and so on, until the last layer of 3D printing is completed and the machine stops working.

[0023] During the 3D printing process of each layer, when it is necessary to 3D print structures with different gradient mechanical properties or easily removable support structures, the y' adjustment mechanism drives the optical engine module to move along y to switch between tunable optical engine I, tunable optical engine II and tunable optical engine III, thereby achieving light switching of different grayscale values ​​to perform grayscale printing, and obtaining structures with different gradient mechanical properties or easily removable support structures.

[0024] This invention provides a photopolymerization micro / nano 3D printing device and method for achieving gradient mechanical structures through grayscale control. Based on low-cost, high-precision, and large-area printing, the worktable is immersed in liquid resin in the material tank and moves from top to bottom, eliminating the need for a release film and avoiding the problem of difficult-to-form microstructures after demolding. Simultaneously, adjustable optical engines I, II, and III, covering different grayscale values ​​from 0 to 255, are arranged through movable optical engine modules to control different grayscale printing. Special structures (such as springs) can be achieved through compression, or conventional structures can be supported by vibration, thus realizing gradient mechanical structures and locally reinforced structures. Furthermore, by achieving gradient mechanical performance structures or locally reinforced mechanical structures, localized grayscale enhancement of material toughness and fracture crack direction can be achieved, avoiding or mitigating defects such as stress concentration, cracking, and spalling that occur during the use of single mechanical structures, increasing the structural strength of parts, and enabling the manufacture of lighter, stronger, and more environmentally friendly functional parts. Attached Figure Description

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The accompanying drawings, which are included to provide a further understanding of the invention and constitute a part of this application, illustrate exemplary embodiments of the invention and, together with their descriptions, serve to explain the invention and do not constitute an undue limitation thereof.

[0026] Figure 1 This is a three-dimensional structural schematic diagram of the photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation, provided by the present invention.

[0027] Figure 2 This is a side view of a schematic diagram of a photopolymer micro / nano 3D printing device that provides grayscale control to achieve gradient mechanical structures.

[0028] Figure 3 This is a schematic diagram of the provided printing platform.

[0029] Figure 4 This is a system schematic diagram of the provided dimmer.

[0030] Figure 5 This is a flowchart of the photopolymerization micro / nano 3D printing method for achieving gradient mechanical structures through grayscale modulation. Detailed Implementation

[0031] Existing photopolymer 3D micro / nano printing technologies mostly employ axial movement and layer-by-layer exposure printing. Photopolymer 3D printing equipment using photopolymer digital micromirror device (DMD) chips can easily change the printed pattern by modifying parameters. However, this approach suffers from the following technical problems: The optical engine exposes the printed part through a centrifugal membrane from bottom to top, requiring the work platform to overcome the adhesion between the printed part and the release film for demolding. At the micro / nano scale, demolding failure or printing defects are highly likely. Manual removal of printing supports at the micro / nano scale can easily damage the printed parts, while not using supports leads to printing defects. Furthermore, it cannot achieve gradient or localized enhanced exposure to achieve better structural mechanical properties, resulting in defects such as stress concentration, cracking, and peeling during use of single-mechanical structures. The manufactured functional parts also suffer from drawbacks such as high weight and undesirable structural mechanical properties.

[0032] To address the aforementioned problems, this invention provides a photopolymerization micro / nano 3D printing device for achieving gradient mechanical structures through grayscale modulation, comprising a base, an optomechanical module, a printing platform, and a material tank.

[0033] An inverted L-shaped column is mounted on the base. The optical engine module is positioned on the horizontal section of the L-shaped column. The optical engine module includes three adjustable optical engines (I, II, and III) arranged in an array along the y-axis, covering grayscale values ​​from 0 to 255. A material tank is mounted on the base with its opening facing upwards. A connecting plate is positioned between the base and the material tank, and the connecting plate has a rotary device for driving the material tank to rotate around a vertical central axis. An x-axis adjustment mechanism, a y-axis adjustment mechanism, and a z-axis adjustment mechanism are also located between the base and the connecting plate. The x-axis adjustment mechanism drives the material tank to adjust its position along the x-axis; the y-axis adjustment mechanism drives the material tank to adjust its position along the y-axis; and the z-axis adjustment mechanism drives the material tank to adjust its position along the z-axis, thereby adjusting the distance from the liquid surface in the material tank to the optical engine module and achieving focusing adjustment. The printing platform is set inside the material tank and includes a worktable, a U-shaped block, and a connecting block. The worktable is connected to the connecting block via the U-shaped block, and the connecting block is driven by a lifting mechanism to move the worktable up and down, enabling a layer-by-layer printing process. Surface or point printing is achieved based on the surface or point mask projections of dimmable light engines I, II, and III. The U-shaped block is driven by a control servo motor to rotate, causing the worktable to tilt relative to the material tank. Combined with multi-axis linkage, curved surface printing is achieved. The horizontal section of the L-column is equipped with a y-guide rail. The optical engine module slides on the y-guide rail and is driven by a y'-axis adjustment mechanism. The y'-axis adjustment mechanism drives the optical engine module to move along the y-axis, switching between dimmable light engines I, II, and III to achieve different grayscale values ​​for grayscale printing, resulting in structures with different gradient mechanical properties and easily removable support structures.

[0034] It should be noted that the photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale adjustment provided by this invention also includes a control system. The control system is connected to the adjustable optical engine I, adjustable optical engine II, and adjustable optical engine III of the optomechanical module for grayscale adjustment. The control system is also connected to the x-axis adjustment mechanism, y-axis adjustment mechanism, z-axis adjustment mechanism, and rotation device to control the movement of the material trough position and angle. The control system is connected to the printing platform to control the up-and-down movement and tilting motion of the worktable. The control system can be an industrial computer, a PLC programmable controller, a computer, or other precision control system.

[0035] When using the photopolymer micro / nano 3D printing equipment that achieves gradient mechanical structures through grayscale control, the worktable immerses itself in the resin tank and moves from top to bottom, eliminating the need for a release liner and avoiding the problem of difficult-to-form microstructures after demolding. Simultaneously, by using dimmable units I, II, and III, different grayscale printing can be controlled. Special structures (such as springs) can be achieved through compression, or conventional structures can be achieved by vibration to remove supports, thus realizing gradient mechanical structures and locally reinforced structures. Furthermore, it achieves gradient mechanical performance structures or locally reinforced mechanical structures, and can enhance material toughness and fracture crack direction through localized pore grayscale, enabling the manufacture of lighter, stronger, and more environmentally friendly functional parts.

[0036] The construction structure and method provided by the present invention will be specifically described below with reference to the accompanying drawings and through specific embodiments. It should be noted that the specific implementations are only some preferred examples, not all examples.

[0037] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, a preferred embodiment of a photopolymerization micro / nano 3D printing device for achieving gradient mechanical structures through grayscale control provided by the present invention includes an L-pillar 1, an optomechanical module 2, a printing platform 3, a material tank 4, an x-axis lead screw slide 5, a y-axis lead screw slide 6, a connecting plate 7, a z-axis lead screw slide 8, a base 9, a rotary device 10, a lead screw 11, a guide rail frame 12, an optomechanical lead screw guide rail 13, a coupling 14, a stepper motor 15, and a z-axis slide 16.

[0038] like Figure 1 , Figure 2 As shown, in some preferred embodiments, the L-pillar 1 is welded and fixed to the base 11. The optical engine lead screw guide rail 13 consists of the L-pillar 1, the optical engine module 2, the lead screw 11, the coupling 14, and the stepper motor 15. The coupling 14 connects the shafts of the lead screw 11 and the stepper motor 15. The stepper motor 15 is fastened to one side of the L-pillar 1 with screws. The optical engine module 2 forms a threaded engagement with the lead screw 11. The optical engine module 2 moves in the y-axis direction by controlling the working state of the stepper motor 15. The optical engine module 2 includes adjustable optical engines I, II, and III with grayscale values ​​from 0 to 255. The stepper motor 15 drives the lead screw 11, causing the optical engine slider to slide back and forth to switch between the three adjustable optical engines, thereby switching between different grayscale values ​​of light to complete grayscale printing and obtain a mechanism with different gradient mechanical properties or a support structure that is easier to remove.

[0039] The tunable light machine I, tunable light machine II and tunable light machine III each include a tunable laser 2a, a beam corrector 2b, an energy controller 2c, a beam shape setter 2d, a light shield 2e, an energy detector 2f, a grayscale film 2g, a mask 2h and an objective lens 2i.

[0040] like Figure 1 , Figure 2 and Figure 3 As shown, in some preferred embodiments, the printing platform 3 is located inside the material trough 4. The printing platform 3 is fixedly connected to the material trough 4 via a threaded flange 17. The material trough 4 is fastened to the rotating device 10 via bolts, thus forming a single unit consisting of the printing platform 3, the material trough 4, and the rotating device 10. The rotating device 10 consists of a rotating support 10-1, a connecting flange 10-2, and a stepper motor 10-3. The rotating support 10-1 is fastened to the material trough 4 via screws, the connecting flange 10-2 is fastened to the rotating support 10-1 via screws, the shaft of the stepper motor 10-3 is fastened to the connecting flange 10-2, and the stepper motor 10-3 is fastened to the connecting plate 7 via screws. The stepper motor 10-3 drives the rotating motion of the connecting flange 10-2, thereby causing the printing platform 3 and the material trough 4 to rotate.

[0041] like Figure 4 As shown, the printing platform 3 comprises a worktable 3-1, a U-shaped block 3-2, a control servo motor 3-3, a connecting block 3-4, and a lead screw motor 3-5. The worktable 3-1 is threadedly fastened to the U-shaped block 3-2, and the U-shaped block 3-2 is threadedly fastened to the rotation shaft of the control servo motor 3-3. The base of the control servo motor 3-3 is fixedly connected to the lead screw of the connecting block 3-4 and the lead screw of the lead screw motor 3-5. The lead screw motor 3-5 drives the connecting block 3-4 to move up and down, thereby realizing the layer-by-layer printing process by moving the worktable from top to bottom. Surface or point printing is achieved based on the surface mask projection or point mask projection of the adjustable optical engine I, optical engine II, and optical engine III. The control servo motor 3-3 drives the rotation of the U-shaped block 3-2 to achieve the tilting movement of the worktable 3-1 relative to the material trough 4. With multi-axis linkage, curved surface printing can be completed well.

[0042] like Figure 3 As shown, in some preferred embodiments, the base of the stepper motor 10-3 is fastened to the connecting plate 7 with screws, and the connecting plate 7 is fastened to the y-axis lead screw slide 6 with screws. The y-axis motor drives the y-axis lead screw slide 6 to slide the connecting plate 7 in the y-axis direction, the x-axis motor drives the x-axis lead screw slide 5 to move the y-axis lead screw slide 6 in the x-axis direction, the base of the x-axis lead screw slide is welded to the guide rail frame 12, and the z-axis motor drives the z-axis lead screw slide 8 to slide the guide rail frame 12 up and down, thereby adjusting the distance from the liquid surface of the material tank 4 to the optical engine, realizing high-precision optical engine focusing adjustment, and obtaining printed parts with higher precision dimensions.

[0043] like Figure 4 As shown, in some preferred embodiments, the dimmer I, dimmer II, and dimmer III systems have the same composition, such as... Figure 4 As shown, the main functions of each part are as follows:

[0044] Component Function Adjustable laser Light source, emitting laser of specific wavelength (around 405nm). Beam corrector Correct the direction of the light beam, making the laser beam as parallel as possible. Energy controller Control the energy of the final exposure on the silicon wafer, under or over exposure will seriously affect the quality of the image. Beam shape setter Set the shape of the beam, such as round, ring, etc. Different beam shape has different optical properties. Shutter Prevent the light beam from shining on the liquid resin when it is not needed. Energy detector Detect whether the final energy of the light beam meets the exposure requirements and feedback to the energy controller for adjustment. Gray scale Gray scale with certain reflectivity. Mask A glass plate with patterns, forming a light image. Objective lens Objective lens is used to compensate for optical errors and scale down the circuit diagram proportionally.

[0045] Dimmable diaphragm I, dimmable diaphragm II, and dimmable diaphragm III cover different ranges of grayscale values ​​from 0 to 255. For example, in some preferred embodiments, the grayscale value of dimmable diaphragm I can be adjusted between 0 and 85, the grayscale value of dimmable diaphragm II can be adjusted between 86 and 180, and the grayscale value of dimmable diaphragm III can be adjusted between 181 and 255.

[0046] In practical implementation, grayscale images are used to adjust the grayscale of the model. Different reflectivities of grayscale images can form 11 levels of grayscale variation ranging from 0 to 10, with the highest grayscale being pure black and the lowest being pure white. Grayscale printing is used as needed to facilitate model support. The photomask is a photolithography photomask. Domestic photomasks can achieve submicron precision, while imported photomasks can achieve nanometer precision. Digital micromirror device (DMD) chips, currently some high-end DMD chips can achieve a precision of 5.4µm. Due to the low resolution and high cost of digital micro-mirror devices (DMD) chips, this technology uses mask imaging to replace the DMD chip imaging currently proposed by scholars, further improving printing accuracy and enabling large-area and cross-scale (printing size can range from micro-nano to decimeter level) scanning. Since the size of DMD pixels is mostly 14μm×14μm (or 16μm×16μm), further reducing it by a scaling mirror to improve printing accuracy results in a smaller printing area, which makes it impossible to meet the accuracy and size requirements for printing large parts. Mask technology is relatively mature, and the accuracy can easily reach sub-micron or even nanometer level, which can better overcome this defect.

[0047] Below, in conjunction with the appendix Figure 5 The present invention provides a further explanation of the photopolymerization micro / nano 3D printing method for achieving gradient mechanical structures through grayscale modulation.

[0048] In some preferred embodiments, the photopolymerization micro / nano 3D printing method for achieving gradient mechanical structures through grayscale modulation includes the following steps:

[0049] S10: Select a suitable liquid resin material according to the performance of the designed part, and pour the selected liquid resin material into the material tank 4;

[0050] S20: Import the designed and sliced ​​3D model into the machine, select the model you need, press start, and the machine's X, Y, and Z axes return to the reference coordinate origin. The processor in the machine processes according to the set model. The optical engine module 2 emits light, and the liquid resin material that is illuminated by the light quickly solidifies. In areas without light, the liquid resin material remains in its original state. When printing the support part, move the optical engine module 2 to switch to grayscale printing, which can reduce the hardness of the support part and facilitate the removal of the support after the whole printing is completed. It can realize the compression or tension of vibration or special structures (such as springs) to achieve efficient removal of the support without damaging the printing mechanism. The machine can realize the movement of parts on the Y, X, and Z axes and a certain tilt angle according to the processing needs of the product's 3D model, thereby realizing multi-axis linkage.

[0051] S30: After processing one layer, the worktable 3-1 automatically descends one layer according to the parameters to process the second layer. When the last layer is processed, the machine stops working. At this point, the part is complete, and the liquid resin remains on top of the liquid material. The worker can then remove the part. When printing the next part, the worker only needs to press the start button. The machine's reference coordinate origin is the coordinated X, Y, and Z axes, ensuring the lens is directly below the center of the solution tank, and the worktable coincides with the bottom of the solution tank.

[0052] Compared with existing technologies, the photopolymerization micro-nano 3D printing equipment and printing method for achieving gradient mechanical structures by using grayscale control provided by this invention has the following technical advantages on the basis of achieving low cost, high precision and large area printing: (1) The worktable is immersed in the resin tank and moves from top to bottom without the need for a release film, thus avoiding the problem of difficult molding of the microstructure after demolding; (2) By arranging the adjustable optical engine I, adjustable optical engine II and adjustable optical engine III through the movable optical engine module, different grayscale printing can be controlled. Special structures (such as springs) can be compressed or conventional structures can be removed by vibration to achieve gradient mechanical structures and local reinforced structures; (3) Gradient mechanical performance structures or local reinforced mechanical structures are realized. Local pore grayscale can be used to enhance the toughness of materials and the direction of fracture cracks, avoiding or alleviating defects such as stress concentration, cracking and peeling caused by single mechanical structures during use, increasing the structural strength of parts, and manufacturing lighter, stronger and more environmentally friendly functional parts.

[0053] The above are merely preferred embodiments of the present invention and are not limited to the examples given. Improvements and modifications made by those skilled in the art within the scope of the present invention are also within the protection scope of the present invention.

Claims

1. A photopolymerization micro / nano 3D printing device for achieving gradient mechanical structures through grayscale adjustment, characterized in that: Includes a base (9), an optical engine module (2), a printing platform (3), and a material trough (4); An inverted L-shaped column (1) is provided on the base (9). The optical engine module is provided on the horizontal section extending along the y direction of the L-shaped column. The optical engine module includes tunable optical engine I, tunable optical engine II and tunable optical engine III arranged in an array along the y direction. The tunable optical engine I, tunable optical engine II and tunable optical engine III cover gray values ​​in different ranges from 0 to 255. The material tank (4) is arranged on the base (9) with its opening facing upward. A connecting plate (7) is provided between the base (9) and the material tank (4). A rotary device (10) for driving the material tank (4) to rotate around the vertical central axis is provided on the connecting plate (7). An x-axis adjustment mechanism, a y-axis adjustment mechanism and a z-axis adjustment mechanism are provided between the base (9) and the connecting plate (7). The x-axis adjustment mechanism is used to drive the material tank (4) to adjust its position along the x-axis. The y-axis adjustment mechanism is used to drive the material tank (4) to adjust its position along the y-axis. The z-axis adjustment mechanism is used to drive the material tank (4) to adjust its position along the z-axis, so as to adjust the distance from the liquid surface of the material tank (4) to the optical engine module (2) and realize the focusing adjustment. The printing platform (3) is set in the material tank (4). The printing platform (3) includes a worktable (3-1), a U-shaped block (3-2), and a connecting block (3-4). The worktable (3-1) is connected to the connecting block (3-4) through the U-shaped block (3-2). The connecting block (3-4) is driven by the lifting mechanism and can drive the worktable (3-1) to move from top to bottom to realize the layer-by-layer printing process. The surface or point printing is realized according to the surface mask projection or point mask projection of the dimmer I, dimmer II, and dimmer III. The U-shaped block (3-2) is driven by the control servo motor to drive the U-shaped block (3-2) to rotate and drive the worktable (3-1) to tilt relative to the material tank (4). With the help of multi-axis linkage, curved surface printing is realized. The horizontal section of the L-column is provided with a y-guide rail. The optical engine module is slidably mounted on the y-guide rail and driven and connected to the y'-direction adjustment mechanism. The y'-direction adjustment mechanism is used to drive the optical engine module to move along the y-direction to switch between adjustable optical engine I, adjustable optical engine II and adjustable optical engine III, realize the switching of light with different gray values ​​to perform grayscale printing, and obtain structures with different gradient mechanical properties and support structures that are easier to remove.

2. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 1, characterized in that: The tunable optical engine I, tunable optical engine II, and tunable optical engine III each include a tunable laser (2a), a beam corrector (2b), an energy controller (2c), a beam shaper (2d), a light shield (2e), an energy detector (2f), a grayscale imager (2g), a photomask (2h), and an objective lens (2i). The tunable laser (2a) emits laser light of a specific wavelength as a light source; the beam corrector (2b) corrects the incident direction of the laser beam to make it as parallel as possible; and the energy controller (2c) controls the final illumination onto the silicon wafer. Energy, underexposure, or overexposure will severely affect image quality; the beam shape setter (2d) is used to set the beam to different shapes such as circular and annular, and different beam states have different optical characteristics; the energy detector (2f) is used to detect whether the final incident energy of the beam meets the exposure requirements and feeds back to the energy controller for adjustment; the grayscale film has a certain reflectivity and is used to adjust the grayscale of the model; the mask (2h) is a glass plate with a pattern and is used to form a light image; the objective lens (2i) is used to compensate for optical errors and scale down the circuit diagram proportionally.

3. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 2, characterized in that: The grayscale film (2g) can form 11 levels of grayscale variation in the range of 0-10 with different reflectivities, the highest grayscale being pure black and the lowest grayscale being pure white.

4. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale control according to claim 2 or 3, characterized in that: The photomask (2h) is a photolithography photomask, and the precision of the photomask (2h) is at the submicron or nanometer level.

5. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 1, characterized in that: The y' adjustment mechanism includes a lead screw (11) and a stepper motor. The lead screw (11) is arranged along the y guide rail (13). The optomechanical module (2) is threadedly engaged with the lead screw (11). The stepper motor is connected to the lead screw (11) through a coupling (14).

6. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 1, characterized in that: The printing platform (3) is fixedly connected to the material trough (4) via a threaded flange (17), and the material trough (4) is fixedly connected to the rotary device (10). The printing platform (3), the material trough (4), and the rotary device (10) form an integrated unit.

7. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 1 or 6, characterized in that: The rotary device (10) includes a rotary support (10-1), a connecting flange (10-2), and a stepper motor. The rotary support (10-1) is fixedly connected to the material trough (4), and the connecting flange (10-2) is fixedly connected to the rotary support (10-1). The stepper motor is connected to the connecting flange (10-2) for transmission, so as to drive the connecting flange (10-2) to rotate through the stepper motor, thereby driving the printing platform (3) and the material trough (4) to rotate.

8. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale control according to claim 1, 2, or 3, characterized in that: The worktable (3-1) is fixedly connected to the U-shaped block (3-2), the U-shaped block (3-2) is fixedly connected to the rotation axis of the control servo motor (3-3), the base of the control servo motor (3-3) is fixedly connected to the connecting block (3-4) and the lead screw of the lead screw motor (3-5), the lead screw motor (3-5) is used to drive the connecting block (3-4) to move up and down, and the control servo motor (3-3) is used to drive the rotation of the U-shaped block (3-2) to realize the tilting movement of the worktable (3-1) relative to the material trough (4), and cooperate with multi-axis linkage to complete the curved surface printing.

9. The photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation according to claim 1, characterized in that: The connecting plate (7) is fixedly connected to the y-axis lead screw slide (6). The y-axis motor drives the y-axis lead screw slide (6) to make the connecting plate (7) slide in the y-axis direction. The x-axis motor drives the x-axis lead screw slide (5) to make the y-axis lead screw slide (6) move in the x-axis direction. The base of the x-axis lead screw slide is fixedly connected to the guide rail frame (12). The z-axis motor drives the z-axis lead screw slide (8) to make the guide rail frame (12) slide up and down. The distance from the liquid surface of the material tank (4) to the optical engine is adjusted to achieve high-precision optical engine focusing adjustment.

10. A photopolymerization micro / nano 3D printing method for achieving gradient mechanical structures through grayscale modulation, using the photopolymerization micro / nano 3D printing equipment for achieving gradient mechanical structures through grayscale modulation as described in claims 1 to 9, characterized in that: Select a suitable liquid resin material and put it into the material tank (4); The first layer of 3D printing of the model: The control table starts from the origin of the reference coordinates and moves along the y-axis, x-axis, z-axis and a certain tilt angle according to the set path to achieve multi-axis linkage. When the optical engine module (2) emits light, the liquid resin material that is illuminated by the light quickly solidifies, while the liquid resin material that is not illuminated by the light remains in its original state until the first layer of 3D printing of the model is completed. After the first layer of 3D printing of the model is completed, the workbench (3-1) descends one layer according to the set height to start the second layer of 3D printing. This cycle continues until the last layer of 3D printing is completed, at which point the machine stops working. During the 3D printing process of each layer, when it is necessary to 3D print structures with different gradient mechanical properties or support structures that are easier to remove, the y' adjustment mechanism drives the optical engine module (2) to move along y to switch between tunable optical engine I, tunable optical engine II and tunable optical engine III, thereby achieving light switching of different gray values ​​and performing grayscale printing to obtain structures with different gradient mechanical properties or support structures that are easier to remove.

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