Light-curing 3D printing device based on six-axis collaborative robot and use method thereof

Abstract

A six-axis collaborative robot-based photocuring 3D printing device relates to the field of printing equipment and application methods, including a frame, an optical system, an electromechanical transmission system, and a host computer. The optical system includes a UV projector, a beam splitter, a CMOS camera, a UV lens, and a reflector mounted at the lower end of the frame. The electromechanical transmission system includes a two-axis linear translation stage mounted on a fixed plate, a printing platform, a six-axis collaborative robot, a resin tank, a release film, an oxygen-permeable film, a resin scraper, a neodymium magnet, a piezoelectric sheet, a waveform generation / amplification system, and a cleaning tank. The waveform generation / amplification system is mounted in an electrical control box. The method for using the six-axis collaborative robot-based photocuring 3D printing device includes 10 steps. The present invention drives the six-axis collaborative robot to complete tasks including printing, refilling, and cleaning through pre-programmed programming on the host computer. It can freely combine discrete / continuous and multiple spatial arrangement patterns of printing components for different structures, and can print complex structures.

Description

Technical Field

[0001] The present invention relates to the technical field of printing equipment and application methods, and in particular to a light-curing 3D printing equipment based on a six-axis collaborative robot and a method for using the same. Background Art

[0002] Stereolithography (3D printing) technologies are primarily categorized into stereolithography (SLA), two-photon lithography (TPL), projection micro-stereolithography (PμSL), continuous liquid interface production (CLIP), and volumetric additive manufacturing (VAM). As the most mature and widely used 3D printing technology, stereolithography (SLA) is being widely applied in industrial production and academic research fields, including flexible and wearable electronics, anisotropic and mechanically reinforced structural materials, new energy, and bio- and tissue engineering. It is used to manufacture products and functional components based on various advanced materials. To meet the diverse demands of these diverse fields, stereolithography (SLA) must be applicable to a wide range of materials, including polymers, ceramics, metals, plastics, and corresponding composite materials. Furthermore, it must be capable of highly automated multi-material 3D printing. For example, flexible and wearable electronic components often contain both conductive and insulating materials, while soft robots are often composed of both rigid and flexible materials. Furthermore, in composite-based applications, it is necessary to be able to spatially arrange 0-, 1-, or 2-dimensional functional fillers in the composite material to achieve significantly enhanced, anisotropic properties, while further reducing the processing difficulty by reducing the required filler content. For example, in structural material applications, significantly enhanced mechanical properties can be achieved by spatially arranging a small amount of carbon fibers or carbon nanotubes; in thermal management applications based on nanocomposites, highly anisotropic in-plane and out-of-plane thermal conductivity can be achieved by spatially arranging nanomaterials such as boron nitride nanosheets.

[0003] Currently, conventional multi-material photocuring 3D printers have a very low degree of automation due to structural limitations, and require repeated manual intervention during the printing process, making it difficult to meet the high-throughput requirements of large-scale production. Furthermore, it is difficult to take into account various types of photocurable resins with vastly different components and rheological properties. In particular, it is impossible to achieve spatial arrangement of polymer monomers or 0-, 1-, or 2-dimensional nanomaterials contained in various types of photocurable resins based on external fields such as shear force and acoustic waves. Furthermore, the single Z-axis movement working mode of these 3D printers is relatively simple, limiting the effective printing area and the printability of complex structures, or requiring the design of additional support structures with the help of algorithms or software. Summary of the Invention

[0004] In order to overcome the drawbacks of existing 3D printing equipment due to technical limitations as described in the background technology, the present invention provides a six-axis collaborative robot driven by preset programming, which can complete tasks including printing, material changing, cleaning, etc., thereby improving work efficiency. It can select discrete / continuous and a variety of spatial arrangement patterns for free combination printing products for different structures, and can print more complex structures. The light-curing 3D printing device based on the six-axis collaborative robot and its use method are provided.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] The photocuring 3D printing device based on a six-axis collaborative robot includes a frame, an optical system, an electromechanical transmission system and a host computer; the optical system includes an ultraviolet projector, a beam splitter, a CMOS camera, an ultraviolet lens, and a reflector installed on one side of the lower end of the frame, the host computer is installed on the other side of the lower end of the frame, the ultraviolet projector is installed on the left end of the beam splitter, the CMOS camera is installed at the lower end of the beam splitter, the ultraviolet lens is installed at the right end of the beam splitter, and the reflector is installed at the right end of the ultraviolet lens; the electromechanical transmission system includes a fixed plate, two two-axis linear translation stages, a printing platform, a six-axis collaborative robot, multiple resin tanks, release films, oxygen-permeable films, resin scrapers, neodymium magnets, piezoelectric sheets, waveform generation / amplification systems and cleaning tanks, the sliding block of the first two-axis linear translation stage is installed at the lower end of the fixed plate, the lower end of the first two-axis linear translation stage is installed at the upper end of the frame, the forearm of the six-axis collaborative robot and the upper end of the printing platform are installed together, and the lower end of the six-axis collaborative robot is installed On the fixed plate and the fixed seat at the rear end of the frame, the lower ends of multiple resin tanks are respectively provided with an opening, and the lower ends of the first resin tank and the third resin tank are respectively installed with release films; the lower part of the sliding block of the first two-axis linear displacement stage and the upper end of the resin scraper are installed together, the first two-axis linear displacement stage is installed on the fixed plate located at the upper end of the first resin tank, the oxygen permeable membrane is installed on the inner lower end of the second resin tank, the annular neodymium magnet is installed on the outer end of the second set of resin tanks, the two piezoelectric sheets are respectively installed on the two side ends of the third resin tank, the cleaning tank is installed on the right end of the third resin tank, and the waveform generation / amplification system is installed in the electrical control box at the right end of the frame; the signal output end of the waveform generation / amplification system is electrically connected to the signal input end of the piezoelectric sheet, and the control signal output end of the host computer is electrically connected to the control signal input end of the six-axis collaborative robot, the two two-axis linear displacement stages, the printing platform, the waveform generation / amplification system, the ultraviolet projector, and the CMOS camera.

[0007] Furthermore, the ultraviolet light projector is based on a digital micromirror device or a liquid crystal display, and is used to generate an ultraviolet light projection pattern required for photocuring and control the accuracy of the projection pattern.

[0008] Furthermore, the two dual-axis linear translation stages are used to control the up-and-down, left-and-right, and forward-and-backward movement of the resin scraper, and the up-and-down, left-and-right, and forward-and-backward movement positions of all components on the fixed plate; the printing platform is used to generate and carry the object to be printed.

[0009] Furthermore, the multiple resin tanks are used to hold different light-curing 3D printing resins; the material of the release film is nFEP, and the material of the oxygen-permeable film is one of Teflon 2400 or spin-coated polydimethylsiloxane, and the thickness of both films ranges from 40μm to 100μm; the resin scraper is used to scrape the light-curing resin flat and apply spatial arrangement through shear force.

[0010] Furthermore, the neodymium magnet can generate a directionally controllable magnetic field with an intensity of 100 mT; the waveform generation / amplification system is used to control the piezoelectric plate to generate acoustic standing waves, including a waveform generator, an RF waveform amplifier and a programmable DC power supply. The waveform generator can generate a sine wave with a maximum frequency of 150 MHz. The sine wave is amplified by the RF waveform amplifier and then applied to the piezoelectric plate in the forward and reverse directions respectively. The RF waveform amplifier is powered by a programmable DC power supply. The center frequency of the piezoelectric plate is adjustable between 200 kHz and 10 MHz.

[0011] Furthermore, the cleaning tank is used to contain a cleaning liquid for cleaning the light-curing resin, and the cleaning liquid is one of deionized water, alcohol, and isopropyl alcohol.

[0012] The method for using a light-curing 3D printing device based on a six-axis collaborative robot includes the following steps: S1: Designing the component structure according to the performance of the target component through the host computer software program. Specifically, the structure includes material composition, spatial distribution and spatial arrangement; S2: Designing and preparing light-curing resin based on the designed component structure; S3, based on the design of steps S1 and S2, the host computer generates a printing program; S4: Focusing the optical system, adjusting the height of the master control platform through the second two-axis linear translation stage according to the design, observing the focus clarity of the projected pattern through the optical CMOS camera until the focal plane of the optical system coincides with the plane of the release film or the oxygen permeable film; S5: Adding corresponding light-curing resin to the three resin tanks according to the type of designed component; S6: For the resin that is scraped and spatially arranged with a resin scraper and the in-plane shear force, the first two-axis linear translation stage adjusts the single-layer scraping thickness and scraping speed according to the printing layer thickness set by the host computer program, and scrapes the first layer of resin flat. The six-axis collaborative robot drives the printing platform to move to the first resin tank, so that the lower surface of the printed component is flush with the focal plane of the optical system, and the direction is parallel to the designed shear force arrangement direction of the current layer, and the optical system is projected according to the preset parameters; S7: For the resin that uses acoustic waves for in-plane spatial arrangement, the waveform generation / amplification system generates a corresponding sine wave according to the in-plane spatial arrangement design. The sine wave is amplified by the RF waveform amplifier and applied to a pair of piezoelectric plates in the positive and negative directions respectively. The piezoelectric plates generate standing waves, so that the nanomaterials in the third resin tank are spatially arranged. Then the six-axis collaborative robot drives the printing platform to move to the second resin tank, so that the lower surface of the printed component is flush with the focal plane of the optical system, and the direction is parallel to the designed arrangement direction of the nanomaterials in the current layer. The optical system is projected according to the preset parameters: S 8: For the resin that is spatially arranged in a plane using a magnetic field, the six-axis collaborative robot drives the printing platform to move to the second resin tank, so that the lower surface of the printed component is flush with the focal plane of the optical system, and the direction is parallel to the arrangement direction of the nanomaterial in the first area of ​​the designed layer. The optical system projects according to the preset parameters, and then the six-axis collaborative robot controls the rotation of the printing platform to make it parallel to the arrangement direction of the nanomaterial in the next area of ​​the layer. The optical system projects according to the preset parameters and repeats until the printing of the current layer is completed; S9, after each material is printed, the six-axis collaborative robot drives the printing platform to immerse the printed part in the cleaning tank to clean the remaining uncured photocurable resin; S10: According to the component design and the resin material used, adjust, combine and repeat steps S6-S9 until all components are printed.

[0013] Furthermore, in step S3, the program includes the spatial motion trajectory of the six-axis collaborative robot, the printing mode of the printing platform, the spatial arrangement design of the resin material surface, the 3D model slicing data, and the optical system parameter settings.

[0014] Furthermore, in step S6, after each layer of printing is completed, the six-axis collaborative robot controls the printing platform to lift, and the scraper flattens the resin wall chart again according to the same parameters, and then prints the next layer according to the same steps; in steps S7 and S8, after each layer of printing is completed, the six-axis collaborative robot controls the printing platform to lift, and prints the next layer according to the same steps.

[0015] Compared with existing technologies, the present invention offers the following advantages: It completely utilizes a pre-programmed host computer to drive a six-axis collaborative robot to complete tasks including printing, reloading, and cleaning. It can freely combine discrete and continuous printing components and various spatial arrangement patterns to suit different structures, enabling the printing of complex structures. In summary, the present invention has promising application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] Figure 1 It is a structural schematic diagram of the light-curing 3D printing equipment based on a six-axis collaborative robot of the present invention.

[0018] Figure 2 This is a flow chart of a method for using a light-curing 3D printing device based on a six-axis collaborative robot according to the present invention.

[0019] Figure 3 Schematic diagram of the material composition and some key layers of the printed object in an embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the spatial trajectory of the high-precision six-axis collaborative robot in an embodiment of the present application.

[0021] Figure 5 Schematic diagram of the Halbach arrangement of neodymium magnets in an embodiment of the present application.

[0022] Figure 6 This is a schematic diagram of the in-plane spatial arrangement of some key layers of the printed object in the embodiment of the present application. DETAILED DESCRIPTION

[0023] Figure 1 、 4, 5, a light-curing 3D printing device based on a six-axis collaborative robot includes a frame (not shown in the figure), an optical system, an electromechanical transmission system and a host computer 1 (for generating a printing program and controlling the entire printing device); the optical system includes an ultraviolet light projector 2 installed on the lower left part of the frame (for generating an ultraviolet light projection pattern required for light curing and controlling the accuracy of the projection pattern), a beam splitter 3 (for dividing the ultraviolet light projection pattern into two beams, one for printing and the other projected onto a CMOS camera for monitoring the focus state of the optical system and the current printing pattern), a CMOS camera 4, an ultraviolet lens 5 (for focusing the projection generated by the ultraviolet light projector on the material trough), a reflector 6 (through 45 ° reflection reduces the space required for installation), the upper computer 1 is installed at the lower right end of the frame, the UV projector 2 is installed at the left end of the beam splitter 3, the CMOS camera 4 is installed at the lower end of the beam splitter 3, the UV lens 5 is installed at the right end of the beam splitter 3, and the reflector 6 is installed at the right end of the UV lens 5; the electromechanical transmission system includes a fixed plate (not drawn in the figure), two two-axis linear translation stages 71 and 72, a printing platform 8, a six-axis collaborative robot 9, three resin tanks 101, 102, 103, a release film 11, an oxygen permeable film 12, a resin scraper 13, a neodymium magnet 14, a piezoelectric piece 15, a waveform generation / amplification system 16 and a cleaning tank 17; the sliding block of the first two-axis linear translation stage 71 Installed in the middle of the lower end of the fixed plate, the lower end of the first biaxial linear displacement stage 71 is installed in the middle of the upper end of the frame, the forearm of the robot 9 and the upper end of the printing platform 8 are installed together, the lower end of the robot 9 is installed on the fixed plate and the fixed seat on the ground at the rear end of the frame, the lower middle ends of the three resin tanks 101, 102, and 103 respectively have an opening, and the lower ends of the first resin tank 101 and the third resin tank 103 are respectively sealed with a release film 11; the lower part of the sliding block of the first biaxial linear displacement stage 71 and the upper end of the resin scraper 13 are installed together, the first biaxial linear displacement stage 71 is installed on the fixed plate located at the upper end of the first resin tank 101, and the oxygen permeable membrane 12 is sealed and installed At the inner lower end of the second resin tank 102, an annular neodymium magnet 14 is installed on the outer end of the second set of resin tanks 102, two piezoelectric sheets 15 are respectively installed on the two side ends of the third resin tank 103, and a cleaning tank 17 is installed on the right side end of the third resin tank 103. The waveform generation / amplification system 16 is installed in the electrical control box located at the right end of the frame; the signal output end of the waveform generation / amplification system 16 is electrically connected to the signal input end of the piezoelectric sheet 15, and the control signal output end of the upper computer 1 is electrically connected to the control signal input end of the six-axis collaborative robot 9, two two-axis linear translation stages 71 and 72, printing platform 8, waveform generation / amplification system 16, ultraviolet projector 2, and CMOS camera 4.

[0024] Figure 1 、 5As shown, the UV projector 2 is based on a digital micromirror device (DMD) or a liquid crystal display (LCD). The UV projector 2 is used to generate the UV projection pattern required for photocuring and control the accuracy of the projection pattern. The resolution of the UV projector 2 is 1920×1080, and the physical size of each pixel is 7.6μm×7.6μm. After focusing by the UV lens 5, the size of each pixel on the focus plane is adjustable between 8.5μm×8.5μm and 25μm×25μm, and the total projection area can reach a maximum of 16.32mm×9.18mm. Two biaxial linear translation stages 71 and 72 are used to control the vertical, horizontal, and forward and backward movement of the resin scraper 13 and the vertical, horizontal, and forward and backward movement of all components on the fixed plate. Specifically, the first biaxial linear translation stage 71 can control the height, scraping distance, and scraping speed of the resin scraper 13, thereby achieving precise control of the thickness of the material scraping layer in the first resin tank 101 and achieving the spatial arrangement of the photocurable resin oligomer molecules or the one-dimensional / two-dimensional nanomaterials contained therein. The printing platform 8 is used to generate and support the object to be printed. The second resin tank 102 achieves the spatial arrangement of the photocurable resin oligomer molecules or the one-dimensional / two-dimensional nanomaterials contained therein. The three resin tanks 101, 102, and 103 are used to hold different light-curable 3D printing materials (all of which are liquid light-curable resins). Specifically, the light-curable resin A selected in the first resin tank is boron nitride nanotubes (BNNT) resin. The average length of BNNS is 1 μm, the average diameter is 100 nm, and the surface is modified with silane coupling agent KH570. The light-curable resin contains 90.8 wt% of 1,6-hexanedioldiacrylate (HDDA), 5 wt% of BNNT, 2 wt% of phosphate dispersant DisperBYK-111, and 2% wt% phenyl bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide, Irgacure 819) and 0.2wt% 2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol (2-(2H-benzotriazol-2-yl)-6-dodecyl-4-methylphenol, Tinuvin 171) were added. The photocurable resin A was uniformly mixed by ultrasonication.The second resin tank 102 contains iron oxide-modified graphene nanosheets (Fe3O4@graphene) resin B. Specifically, the iron oxide is nanoparticles with an average diameter of 200 nm, and the graphene nanosheets have an average diameter of 2 μm and an average thickness of less than 8 nm. The photocurable resin B contains 97.8 wt% HDDA, 0.5 wt% Fe3O4@graphene, and 2 wt% Irgacure 819. The photocurable resin B is uniformly mixed using ultrasonic mixing. The third resin tank 103 contains carbon nanofiber (CNF) resin C. Specifically, the CNF has an average length of 5-50 μm and an average diameter of 200-600 nm. The photocurable resin C contains 50% (w / v) HDDA, 48% (w / v) poly(ethylene glycol) diacrylate (PEGDA700) with an average molecular weight of 700, and 2% (w / v) phenylbis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (Irgacure819). The CNF is uniformly mixed with the photocurable resin C at a ratio of 1.5% (w / v) by ultrasonication. Release film 11 is a 100μm-thick nFEP film with high oxygen permeability, which helps reduce release force. Its UV transmittance at 385nm is no less than 80%. It also possesses excellent mechanical strength, ensuring uniform thickness of the scraped-off layer. It is also chemically inert and does not react with the photocurable resin. Oxygen permeable film 12 is made of either Teflon 2400 or spin-coated polydimethylsiloxane (PDMS), with a thickness ranging from 40μm. A resin scraper 13 is used to scrape the photocurable resin flat and apply shear force to distribute it spatially. Neodymium magnet 14 can generate a magnetic field with a maximum intensity of 100 mT and controllable direction. Waveform generation / amplification system 16 controls the piezoelectric plate to generate acoustic standing waves. It includes a waveform generator, an RF waveform amplifier, and a programmable DC power supply. The waveform generator can generate a sine wave with a frequency of up to 150 MHz. The sine wave is amplified by the RF waveform amplifier and then applied to the piezoelectric plate 15 in both forward and reverse directions. The RF waveform amplifier is powered by a programmable DC power supply. The center frequency of the piezoelectric plate 15 is adjustable between 200 kHz and 10 MHz. A cleaning tank 17 holds isopropyl alcohol, a cleaning solution for cleaning photocurable resin.

[0025] Figure 2 、 3As shown in Figures 4 and 6, a light-curing 3D printing device based on a six-axis collaborative robot and a method for using the same include the following steps: S1, generating a printing program. Specifically, the host computer 1 first calculates the optimal spatial motion trajectory of the collaborative robot 9 according to the geometric structure of the printed object; determines the printing mode of each material component according to the material composition and in-plane arrangement design of the designed object; generates 3D model image slice data and matching optical system parameters according to the spatial motion trajectory of the collaborative robot 9 and the selected material, combined with the geometric structure of the printed object. S2: Focusing the optical system. Specifically, the two-axis linear translation stage 72 first adjusts the lateral position of the assembly platform so that the optical projection pattern coincides with the center of the resin tank 101. The height of the master control platform (which holds all components on the platform) is then adjusted. The focus clarity of the projected pattern is monitored by the CMOS camera 4 in the optical system until the focal plane of the optical system coincides with the plane of the release film 11. The core of this technology is surface-to-surface photocuring 3D printing. The 3D structure model is sliced ​​into a series of 2D patterns using software. These patterns are then projected layer by layer by the UV projector 2 in the optical system. With each layer, the photocurable resin in the corresponding area solidifies. The printing platform 8 then moves to project the next image, and the newly cured layer connects to the previous one. This process repeats until the 3D structure is printed. The optical system's primary function is to project this series of patterns and to monitor the projector's focus. S3: The corresponding photocurable resins A, B, and C are added to resin tanks 101, 102, and 103, respectively. S4, material 1 printing. Specifically, the two-axis linear displacement stage 71 first adjusts the height of the resin scraper 13, sets the single-layer scraping thickness to 50μm, and the scraping speed to 20mm / s. After the upper end of the resin 101 is scraped flat by unidirectional scraping, the high-precision six-axis collaborative robot 9 drives the printing platform 8 to the initial printing position and projects the first layer pattern of material 1 (the projection pattern corresponding to the first layer slice of the 3D printed structure). The specific light intensity is 15mW / cm 2, the exposure time is 4s, and the single layer thickness of material 1 is designed to be 25μm. After the first layer of printing is completed, the high-precision six-axis collaborative robot 9 is lifted by 10cm, tilted at a certain angle, and rotated counterclockwise at a certain angle. The scraper 13 scrapes the resin A in the reverse direction again according to the same parameters to smooth it out. Then, the high-precision six-axis collaborative robot 9 drives the printing platform to the second layer printing position according to the preset material A layer thickness to continue printing (the first layer is solid after printing and will stick to the surface of the printing platform. The scraping is to smooth the light-curing resin in the resin tank for the next layer of printing); repeat S4 until part of the material 1 is printed (the 3D printing process will convert the liquid resin into a solid state). The high-precision six-axis collaborative robot 9 drives the printing platform 8 to immerse the printed part into the cleaning tank to clean the remaining uncured light-curing resin A (liquid resin 1 will remain on the printed structure (cured resin), and these residual resins must be cleaned). S5, material C printing, the high-precision six-axis collaborative robot 9 drives the printing platform 8 to move to the resin tank 103, so that the lower surface of the printed part (cured part) is flush with the focal plane of the optical system; specifically, the center frequency of the PZT piezoelectric piece selected in the resin tank 103 is 1.65MHz, and the waveform generator is set to generate a frequency of 1.65MHz and a voltage peak of V0=25V RMS The sine wave is amplified by an RF waveform amplifier and then applied to the pair of PZT piezoelectric plates in the forward and reverse directions. The RF waveform amplifier is powered by a programmable DC power supply (generating an acoustic standing wave with a certain wavelength. This standing wave can make the carbon fibers contained in the photocurable resin spatially arranged into rows of arrays with a certain spacing, such as Figure 6 As shown in the second row of the figure); the first layer pattern intensity of the optical system projection material 2 is 15mW / cm 2 , the exposure time is 3s, and the single layer thickness of material C is designed to be 10μm; after the first layer is printed, the high-precision six-axis collaborative robot 9 increases the preset layer thickness of material C by 10μm, tilts at a certain angle, and rotates counterclockwise at a certain angle (same as the part of material A, the first layer of material C light-curing resin will be connected to the lower surface of the printed material C after curing. The multi-material here refers to the final printed structure ( Figure 3 ) is composed of three materials); S5 is repeated until the printing of material 2 is completed; the high-precision six-axis collaborative robot 9 drives the printing platform to immerse the printed part into the cleaning tank to clean the remaining uncured light-curing resin C. S6, material B is printed, and the high-precision six-axis collaborative robot drives the printing platform to move to the resin tank 102 so that the lower surface of the printed part is flush with the focal plane of the optical system. Specifically, the neodymium magnets 14 around the resin tank 102 (neodymium magnets are arranged according to Figure 5 After the spatial position relationship is installed (i.e. Halbach arrangement), the direction can be generated as follows Figure 5The uniform magnetic field shown by the central arrow is used to control the spatial orientation of the iron oxide modified graphene nanosheets in material 3) Halbach arrangement as shown in Figure 5 As shown, the north pole of each neodymium magnet and the direction of the magnetic field generated by the Halbach arrangement are shown as the center arrow, and the distance between each neodymium magnet and the center of the resin tank is 30 mm; specifically, the magnetic field strength generated by the Halbach arrangement of the neodymium magnets is 100 mT; the optical system projects the pattern of the first layer area ① of material B, and the light intensity is 15 mW / cm 2 , the exposure time is 3s, and the single layer thickness of material 3 is designed to be 10μm. After completion, the high-precision six-axis collaborative robot rotates counterclockwise and rotates a certain angle counterclockwise, and prints the first layer printing area ② in the same way, repeating until the first layer printing is completed. After completion, the high-precision six-axis collaborative robot raises the preset material B layer thickness by 10μm, tilts a certain angle, and rotates a certain angle counterclockwise (the first layer of photocurable resin will be connected to the lower surface of the already printed material B after curing); repeat S6 until the printing of material 3 is partially completed; the high-precision six-axis collaborative robot 9 drives the printing platform to immerse the printed part into the cleaning tank to clean the remaining uncured photocurable resin B.

[0026] Through the above-mentioned technical solution, the present invention completely drives a six-axis collaborative robot to complete tasks including printing, material changing, and cleaning through pre-programmed programs on a host computer. This solves the problem of existing 3D printers having a low degree of automation and requiring repeated manual intervention, which makes it difficult to meet the high-throughput requirements of large-scale production. The present invention can freely combine and print components in discrete / continuous and multiple spatial arrangement modes for different structures, overcoming the problem that existing technologies have difficulty in balancing various types of photocurable resins with vastly different components and rheological properties. In particular, it cannot achieve spatial arrangement of polymer monomers or contained 0-dimensional, 1-dimensional, or 2-dimensional nanomaterials in various types of photocurable resins based on external fields such as shear force and acoustic waves (existing photocurable 3D printers can only choose one of the discrete / continuous photocurable 3D printing modes, and often can only choose one of the three nanomaterial spatial arrangement modes mentioned in this application). The present invention can print complex structures, overcoming the problems of existing 3D printers that can only work in Z-axis and mobile modes (the cross-sectional area of ​​the printed structure cannot exceed the format of the UV projector), are relatively simple in operation, or require the use of algorithms or software to design additional support structures, which limits the effective printing area and the printability of complex structures.

[0027] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded in all respects as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be included therein.

[0028] In addition, it should be understood that although this specification is described in terms of implementation methods, the implementation methods do not only include an independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in the embodiments can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A six-axis collaborative robot-based light-curing 3D printing device, comprising a frame, an optical system, an electromechanical transmission system, and a host computer; characterized in that: The optical system includes an ultraviolet projector, a beam splitter, a CMOS camera, an ultraviolet lens, and a reflector installed on one side of the lower end of the frame; the upper computer is installed on the other side of the lower end of the frame, the ultraviolet projector is installed on the left end of the beam splitter, the CMOS camera is installed at the lower end of the beam splitter, the ultraviolet lens is installed at the right end of the beam splitter, and the reflector is installed at the right end of the ultraviolet lens; the electromechanical transmission system includes a fixed plate, two two-axis linear displacement stages, a printing platform, a six-axis collaborative robot, multiple resin tanks, release film, oxygen permeable film, resin scraper, neodymium magnet, piezoelectric sheet, waveform generation / amplification system and cleaning tank, the sliding block of the first two-axis linear displacement stage is installed at the lower end of the fixed plate, the lower end of the first two-axis linear displacement stage is installed at the upper end of the frame, the forearm of the six-axis collaborative robot and the upper end of the printing platform are installed together, the lower end of the six-axis collaborative robot is installed on the fixed plate and the fixed seat at the rear end of the frame, the lower ends of the multiple resin tanks respectively have an opening, and the lower ends of the first resin tank and the third resin tank are respectively installed with release films; the first two-axis linear position The lower part of the sliding block of the moving stage and the upper end of the resin scraper are installed together, the first two-axis linear displacement stage is installed on the fixed plate located at the upper end of the first resin tank, the oxygen permeable membrane is installed on the inner lower end of the second resin tank, the annular neodymium magnet is installed on the outer end of the second set of resin tanks, the two piezoelectric sheets are respectively installed on the two side ends of the third resin tank, the cleaning tank is installed on the right end of the third resin tank, and the waveform generation / amplification system is installed in the electrical control box at the right end of the frame; the signal output end of the waveform generation / amplification system is electrically connected to the signal input end of the piezoelectric sheet, and the control signal output end of the upper computer is electrically connected to the control signal input end of the six-axis collaborative robot, the two two-axis linear displacement stages, the printing platform, the waveform generation / amplification system, the ultraviolet projector, and the CMOS camera; the first two-axis linear displacement stage is used to control the up and down, left and right, and forward and backward movement of the resin scraper, and the second two-axis linear displacement stage is used to control the up and down, left and right, and forward and backward movement positions of all components on the fixed plate; the printing platform is used to generate and carry the object to be printed.

2. The light-curing 3D printing device based on a six-axis collaborative robot according to claim 1, characterized in that: The UV projector is based on a digital micromirror device or a liquid crystal display. The UV projector is used to generate the UV projection pattern required for photocuring and control the accuracy of the projection pattern.

3. The light-curing 3D printing device based on a six-axis collaborative robot according to claim 1, characterized in that: Multiple resin tanks are used to hold different light-curing 3D printing resins; the release film is made of nFEP, and the oxygen-permeable film is made of Teflon 2400 or spin-coated polydimethylsiloxane. The thickness of both films ranges from 40μm to 100μm; a resin scraper is used to flatten the light-curing resin and apply shear force to spatially distribute it.

4. The light-curing 3D printing device based on a six-axis collaborative robot according to claim 1, characterized in that: Neodymium magnets can generate a directionally controllable magnetic field with an intensity of 100mT. The waveform generation / amplification system is used to control the piezoelectric plate to generate acoustic standing waves. It includes a waveform generator, an RF waveform amplifier, and a programmable DC power supply. The waveform generator can generate a sine wave with a maximum frequency of 150MHz. The sine wave is amplified by the RF waveform amplifier and then applied to the piezoelectric plate in the forward and reverse directions respectively. The RF waveform amplifier is powered by a programmable DC power supply. The center frequency of the piezoelectric plate is adjustable between 200kHz and 10MHz.

5. The light-curing 3D printing device based on a six-axis collaborative robot according to claim 1, characterized in that: The cleaning tank is used to hold a cleaning liquid for cleaning the light-curing resin. The cleaning liquid is one of deionized water, alcohol, and isopropyl alcohol.

6. The method for using the six-axis collaborative robot-based light-curing 3D printing device according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: S1: designing the component structure according to the performance of the target component through a host computer software program, specifically, the structure includes material composition, spatial distribution and spatial arrangement; S2: designing and preparing a light-curing resin based on the designed component structure; S3: based on the designs of steps S1 and S2, the host computer generates a printing program; S4: Focusing the optical system: The height of the master control platform is adjusted by the second two-axis linear translation stage according to the design, and the focus clarity of the projected pattern is observed by the optical CMOS camera until the focal plane of the optical system coincides with the plane of the release film or the oxygen permeable film; S5: According to the type of designed components, the corresponding light-curing resin is added to the three resin tanks respectively; S6: For resins that are scraped with a resin scraper and spatially arranged with in-plane shear forces, the first two-axis linear translation stage adjusts the single-layer scraping thickness and scraping speed according to the printing layer thickness set by the host computer program. After the first layer of resin is scraped and leveled, the six-axis collaborative robot drives the printing platform to move to the first resin tank so that the lower surface of the printed component is flush with the focal plane of the optical system and the direction is parallel to the designed shear force arrangement direction of the layer. The optical system is projected according to the preset parameters; S7: For the resin that uses acoustic waves for in-plane spatial arrangement, the waveform generation / amplification system generates a corresponding sine wave according to the in-plane spatial arrangement design. The sine wave is amplified by the RF waveform amplifier and applied to a pair of piezoelectric plates in the positive and negative directions respectively. The piezoelectric plates generate standing waves, so that the nanomaterials in the third resin tank are spatially arranged. Then the six-axis collaborative robot drives the printing platform to move to the second resin tank so that the lower surface of the printed part of the components is flush with the focal plane of the optical system, and the direction is parallel to the designed arrangement direction of the nanomaterials in the current layer. The optical system projects according to the preset parameters: S8: For the resin that uses a magnetic field for in-plane spatial arrangement, the six-axis collaborative robot drives the printing platform to move to the second resin tank so that the lower surface of the printed part of the components is flush with the focal plane of the optical system, and the direction is parallel to the designed arrangement direction of the nanomaterials in the first area of ​​the current layer. The optical system projects according to the preset parameters. Then the six-axis collaborative robot controls the rotation of the printing platform so that it is parallel to the arrangement direction of the nanomaterials in the next area of ​​the current layer. The optical system projects according to the preset parameters, and repeats until the printing of the current layer is completed; S9: After each material is printed, the six-axis collaborative robot drives the printing platform to immerse the printed part into the cleaning tank to clean the remaining uncured photocurable resin; S10: According to the component design and the resin material used, adjust, combine and repeat steps S6-S9 until all components are printed.

7. The method for using the six-axis collaborative robot-based light-curing 3D printing device according to claim 6, characterized in that: In step S3, the program includes the spatial motion trajectory of the six-axis collaborative robot, the printing mode of the printing platform, the spatial arrangement design of the resin material surface, the 3D model slicing data, and the optical system parameter settings.

8. The method for using the six-axis collaborative robot-based light-curing 3D printing device according to any one of claim 6, characterized in that: In step S6, after each layer of printing is completed, the six-axis collaborative robot controls the printing platform to rise, and the scraper flattens the resin wall chart again according to the same parameters, and then prints the next layer according to the same steps; in steps S7 and S8, after each layer of printing is completed, the six-axis collaborative robot controls the printing platform to rise, and prints the next layer according to the same steps.

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