A device and method for stereolithography of complex axial light-cured oil channeling pipes

Abstract

The application provides a method for calculating axial photocuring complex oil pipeline sand mold stereoscopic forming, and the device comprises an outer frame, a storage box, an equal-curvature long columnar light-transmitting container, a cylinder lifting mechanism, a numerical control rotary table, a lifting fixing mechanism, a laser projection device, a calibration camera, a C-shaped hot air mechanism, a cooling loop pipeline and an oxygen content monitoring control mechanism and the like. The forming method is that the printing matrix is used to implement the calculation of the axial photocuring complex oil pipeline sand mold stereoscopic forming by using the forming device. In the printing forming environment, the printing matrix in the rotating equal-curvature long columnar light-transmitting container is subjected to multi-angle laser projection, the scattering phenomenon of the light in the non-100% transparent material is represented in real time by using a red LED lamp and a calibration camera, the laser intensity is calibrated, the forming step of layer-by-layer sand laying and then printing is omitted, the resin in the printing matrix is subjected to cross-linking reaction by photopolymerization induction, and the sand mold with small and slender complex oil pipelines is directly formed at one time.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of 3D printing of casting sand molds and CAL calculation axial light solidification printing cross technology, and particularly relates to a calculation axial light solidification complex oil passage pipeline sand mold stereoscopic forming method. BACKGROUND

[0002] With the rapid development of the aerospace field, castings are gradually developing in the direction of complex thin-walled and multi-oil passage pipeline integration. In recent years, the rapidly developing 3D printing sand mold technology has advantages such as no need for molds, short production cycle of castings, and is suitable for the design and development of complex oil passage pipeline castings, which can significantly reduce the production difficulty of castings. However, due to the special forming principle of the sand mold 3D printing technology that loose sand is bonded and accumulated layer by layer, the parts inevitably have layering defects, which affect the precision and mechanical properties of the sand mold, and further affect the surface quality and performance of the castings. Moreover, the low-dimensional units are repeatedly manufactured to realize material accumulation, so as to manufacture a three-dimensional entity, which is slow in forming speed and low in forming efficiency, and it is difficult to realize the flow line type batch production of printed parts. For castings with small, slender and complex thin-walled oil passage pipelines, the traditional sand mold 3D printing technology cannot meet the development needs of modern casting. Therefore, at the present stage, a new sand mold manufacturing method needs to be proposed to provide a new reference for the production of engine castings with small, slender and complex thin-walled oil passage pipelines inside.

[0003] The calculation axial light solidification volumetric printing technology is a new type of 3D printing technology, which can provide faster printing speed than layer-by-layer printing manufacturing, and overcome the geometric and surface limitations of traditional layer-based 3D printing technology. This method is similar to performing a CT scan in reverse, which reconstructs a three-dimensional light dose distribution in the printing matrix by projecting a pattern light containing the center slice information of the printing model, and then quickly polymerizes the printing matrix to overcome the layering effect and realize the rapid forming of the printed part.

[0004] At the present stage, the printing matrix selected by the conventional calculation axial light solidification volumetric printing technology is mostly a material with high optical transparency. Until Madrid-Wolf et al. proposed a scheme for modifying the projection light intensity and other parameters by considering the scattering of light in a non-100% transparent printing matrix to improve the forming degree, which provides the possibility of realizing the calculation axial light solidification volumetric printing forming inside a turbid material. Based on the above research facts and considering the optical properties of silica sand and other sand materials, and aiming at the small, slender and complex structure of the engine sand mold manufacturing, the present application proposes a calculation axial light solidification complex oil passage pipeline sand mold stereoscopic forming method, which provides a new manufacturing idea for the small, slender and complex structure of the engine complex oil passage pipeline. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a method for stereolithography of sand mold of complex oil pipeline with axial photocuring in order to solve the problems of the prior art.

[0006] To solve the above technical problems, the technical scheme adopted by the present application is: a device for stereolithography of sand mold of complex oil pipeline with axial photocuring, comprising an outer frame, a storage tank, an equal-curvature long columnar light-transmitting container, a cylinder lifting mechanism, a numerical control rotary table, a lifting fixing mechanism, a laser projection device, a calibration camera, a C-shaped hot air mechanism, a cooling loop pipeline and an oxygen content monitoring and control mechanism; the cylinder lifting mechanism, the numerical control rotary table, the lifting fixing mechanism, the laser projection device, the calibration camera, the C-shaped hot air mechanism and the cooling loop pipeline are arranged in the outer frame, the oxygen content monitoring and control mechanism is arranged on the outer frame, and the storage tank is arranged outside the outer frame; a coaxial columnar cavity is arranged in the middle of the equal-curvature long columnar light-transmitting container, the cavity of the equal-curvature long columnar light-transmitting container has a U-shaped structure in the axial cross section, the U-shaped structure cavity is communicated with the storage tank through a feeding pipeline, the storage tank is used for storing a printing substrate, and a red LED lamp is arranged at the top of the equal-curvature long columnar light-transmitting container.

[0007] The numerical control rotary table comprises pneumatic clamps, a table box, a table motor, a worm, a turbine, a rotating table top and a feeding pipeline; the table motor drives the worm to rotate, the worm is engaged with the turbine, the turbine is horizontally arranged, the central shaft of the turbine is fixedly connected with the rotating table top, the rotating table top and the turbine are synchronously rotated, the rotating table top is arranged above the table box, a plurality of groups of pneumatic clamps are arranged on the rotating table top, the equal-curvature long columnar light-transmitting container is clamped and fixed by the pneumatic clamps, the table box, the central shaft of the turbine and the rotating table top are provided with a central through hole of the feeding pipeline, so that the U-shaped structure cavity of the equal-curvature long columnar light-transmitting container is communicated with the U-shaped structure cavity; and the table motor drives the worm to rotate.

[0008] The cylinder lifting mechanism is arranged between the outer frame and the numerical control rotary table.

[0009] The lifting fixing mechanism is arranged beside the long columnar light-transmitting container with equal curvature, a rotary motor and a clamping jaw mechanism are arranged above the long columnar light-transmitting container with equal curvature, the rotary shaft of the rotary motor is connected with the clamping jaw mechanism downward, and the clamping jaw mechanism is used for clamping the top of the long columnar light-transmitting container with equal curvature.

[0010] The laser projection device and the C-shaped hot air mechanism are arranged on opposite sides of the long columnar light-transmitting container with equal curvature respectively, the air outlet of the C-shaped hot air mechanism faces the long columnar light-transmitting container with equal curvature, and is used for heating the printing medium in the long columnar light-transmitting container with equal curvature; a lens is further arranged between the laser projection device and the long columnar light-transmitting container with equal curvature, the lens is fixed through a support, the laser emitted by the laser projection device converges on the printing medium in the long columnar light-transmitting container with equal curvature through the lens; the laser of the laser projection device is aligned with the central axis of the long columnar light-transmitting container with equal curvature, a calibration camera is arranged on the other side of the long columnar light-transmitting container with equal curvature, the calibration camera is loaded with a red band-pass filter, the lens of the calibration camera faces the central axis of the long columnar light-transmitting container with equal curvature, and the included angle between the laser projection device, the calibration camera and the central axis of the long columnar light-transmitting container with equal curvature is 90°.

[0011] Preferably, the air cylinder lifting mechanism comprises a top plate and a bottom frame, a folding frame for lifting is slidingly arranged between the top plate and the bottom frame, the folding frame comprises two groups of symmetrically arranged X-shaped rotating shafts, the two groups of symmetrically arranged X-shaped rotating shafts are rotationally connected by two support shafts to form an X-shaped structure, a cross bar is connected between two opposite support shafts of the two groups of X-shaped rotating shafts, and a thrust air cylinder is arranged between the two cross bars; with the change of the length of the thrust air cylinder, the rotation of the two support shafts is realized, so that the lifting and lowering of the top plate are realized; the bottom frame is fixed on the outer frame, and the top plate is fixed with the workbench box body.

[0012] Preferably, the lifting fixing mechanism comprises a lead screw, a lead screw sleeve, a bolt, a vertical gantry structure a, a vertical gantry structure b, a base, and a lifting motor; the base and the vertical gantry structure b are fixed on the outer frame 1, the lead screw is vertically rotationally arranged between the base and the vertical gantry structure b, the vertical gantry structure b is provided with the lifting motor which drives the rotation of the lead screw, the lead screw is further sleeved with the lead screw sleeve, the lead screw sleeve and the vertical gantry structure a are fixed by the bolt, the vertical gantry structure a is fixedly provided with a rotary motor, and the rotary shaft of the rotary motor penetrates through the vertical gantry structure a and is connected with a clamping jaw mechanism downward,

[0013] Preferably, the C-shaped hot air mechanism comprises a C-shaped structure vertically arranged air plate, a plurality of hot air machines are arranged on the air plate, and the hot air outlets of the hot air machines face the long columnar light-transmitting container with equal curvature; a thermocouple is fixed at a position 3mm away from the workbench box body; and the cooling loop pipeline is arranged in the outer frame.

[0014] Preferably, the oxygen content monitoring control mechanism is arranged on the outer frame side wall, and comprises an oxygen content detector, a controller, and a nitrogen storage tank in communication with the inner cavity of the outer frame 1 through a nitrogen delivery pipe, wherein an electromagnetic valve is arranged on the nitrogen delivery pipe, and the controller is electrically connected with the electromagnetic valve, and the oxygen content detector is arranged on the inner side of the outer frame to monitor the oxygen content in the environment of the whole outer frame and control the oxygen content in the environment of the outer frame to be less than 10% through the controller.

[0015] In addition, the present application also provides a method for implementing the axial photocuring complex oil pipeline sand mold stereoscopic forming method, and the method comprises the following steps:

[0016] S1, selecting a mixed formula of a printing substrate according to the complex oil pipeline to be axially photocured and shaping, and then putting the mixed formula into a storage tank for standby use;

[0017] S2, establishing an STL three-dimensional model of the complex oil pipeline sand mold by using software, and designing the size of a columnar cavity in the long columnar light-transmitting container according to the model;

[0018] S3, dividing the structure layer from the center axis to the outermost layer and performing radial slicing on the geometric features of the complex oil pipeline sand mold STL three-dimensional model established in S2, and processing and analyzing the slicing data information, and then loading the image sequence into a laser projection device after the image sequence is arranged;

[0019] S4, clamping and fixing the long columnar light-transmitting container with a clamping jaw mechanism, and sending the printing substrate in the storage tank into the U-shaped structure cavity of the long columnar light-transmitting container through a feeding pipeline, and performing scattering calibration; the scattering calibration is a pre-calibration of the projection laser intensity and other parameters by studying the scattering law before projection, so as to ensure that the laser intensity is sufficient to induce the printing substrate to be cured and shaped when the projection laser passes through the printing substrate and reaches the printing area after being affected by the particle scattering.

[0020] S5, adjusting the environmental temperature and atmosphere of the axial photocuring shaping in the outer frame to a suitable state;

[0021] S6, adjusting the control numerical control rotary table of the cylinder lifting mechanism to the bottom of the long columnar light-transmitting container, and fixing the long columnar light-transmitting container by using a pneumatic clamping jaw, then opening the rotary motor to make the long columnar light-transmitting container rotate around its axis, and opening the laser projection device to project the pattern light containing the current structure layer slicing information into the printing substrate after the pattern light is adjusted by a lens;

[0022] S7, opening the red LED lamp and the calibration camera to perform real-time calibration of spatial resampling, and feeding back the calibration information to adjust the projection parameters such as the laser intensity of the laser projection device in real time, and gradually accumulating the irradiation amount of the printing substrate in the U-shaped structure cavity and causing volumetric curing and shaping.

[0023] S8, continuously projecting and real-time calibration feedback in the curing forming process until the complex oil circuit pipeline printing piece is completed, stopping the projection, cleaning and recycling the un-solidified printing matrix, taking out the complex oil circuit pipeline printing piece, and placing it under laser irradiation for 1-2 hours for curing;

[0024] S9, judging whether the forming degree of the complex oil circuit pipeline printing piece meets the standard, if not, repairing and coating, if meeting the standard, post-processing, so that the complex oil circuit pipeline printing piece meets the required shape index and product delivery.

[0025] Preferably, the mesh number of the sand mold material is selected in the range of 2000-8000 meshes, the sand mold material is in a powder state, and is subjected to fluidization treatment to obtain a sand mold material with liquid fluidity before mixing and preparation;

[0026] The cross-linking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylaminoethyl benzoate;

[0027] The photosensitive component and the sand mold material are mixed in a mass ratio of 6:4, and then ultra-fine fiber material not more than 2% of the total mass of the photosensitive component and the sand mold material is added for preparation, the preparation viscosity is at least 9000 mPa·s, and oscillation is carried out to a bubble-free state to obtain a printing matrix.

[0028] Preferably, the wavelength of the red LED light beam is 678 nm; the laser intensity of the laser projection equipment is selected in the range of 0.5-6 mW / cm 2 , and the wavelength is 405 nm; the laser irradiation curing forming time should be controlled in 60-240 s.

[0029] Preferably, in S8, the static curing is carried out under 405 nm laser irradiation and at a temperature of 60 DEG C for 1-2 h.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] 1. The present application designs a device for calculating the axial light-cured complex oil circuit pipeline sand mold three-dimensional forming, which has novel structure, high efficiency, and can quickly prepare the complex oil circuit pipeline sand mold. The sand mold printing method is designed using the forming device, which eliminates the problems of poor interlayer bonding, poor mechanical properties of the sand mold, and eliminates the problem of layered defects, overcomes the limitations of geometric and surface precision of the traditional sand mold additive manufacturing technology based on the principle of layer-by-layer accumulation forming, and provides a new idea for the preparation of sand molds with small, slender, complex and thin-walled oil circuit pipelines.

[0032] 2、The present application adopts the method of calculating axial light curing complex oil line pipeline sand mold stereoscopic forming, which transits from the sand layer-by-layer paving and printing sand mold manufacturing method to one-time full three-dimensional printing method, saves the step of layer-by-layer paving and printing, reduces the manufacturing time from dozens of minutes to several minutes, greatly shortens the printing time, improves the overall efficiency of sand mold 3D printing, and is more energy-saving and efficient.

[0033] 3、The sand mold manufacturing method adopted by the present application can recycle the uncured printing material, which is 100% reusable, and this 3D printing technology almost does not produce any material waste, is beneficial to green and sustainable development, and can repair and coat the formed sand mold entity, which widens the application of sand mold additive manufacturing technology.

[0034] The technical solutions of the present application will be further described in detail below with the help of the drawings and examples. DETAILED DESCRIPTION

[0035] Figure 1 A flowchart of a calculating axial light curing complex oil line pipeline sand mold stereoscopic forming method disclosed in embodiment 1 of the present application.

[0036] Figure 2 A small-sized slender multi-oil line complex thin-walled pipeline structure example diagram made by the calculating axial light curing complex oil line pipeline sand mold stereoscopic forming method adopted by the present application.

[0037] Figure 3 A structure schematic diagram of a calculating axial light curing complex oil line pipeline sand mold stereoscopic forming simple device of the present application.

[0038] Figure 4 A structure top view of a calculating axial light curing complex oil line pipeline sand mold stereoscopic forming simple device of the present application.

[0039] Figure 5 An isometric view of a numerical control rotary table of the present application.

[0040] Figure 6 An isometric perspective view of a numerical control rotary table of the present application.

[0041] Figure 7 An upper isometric view of a numerical control rotary table of the present application.

[0042] Figure 8 An isometric view of a cylinder lifting mechanism of the present application.

[0043] Figure 9 A side view of a lifting fixing mechanism of the present application.

[0044] Attached Figure Descriptions: 1-Outer frame; 2-Oxygen content monitoring and control mechanism; 3-Laser projection equipment; 4-Lens; 5-Thermocouple; 6-Cylinder lifting mechanism; 7-Telescopic sleeve; 8-Storage bin; 9-CNC rotary table; 10-C-type hot air mechanism; 11-Lifting and fixing mechanism; 12-Cooling circuit pipe; 13-Calibration camera; 14-Red LED light; 15-Workbench motor; 16-Worm gear; 17-Feeding pipe; 18-Workbench housing; 19-Turbine. ; 20-Rotating table; 21-Pneumatic gripper; 22-Printing substrate; 23-Columnar cavity; 24-Curved long columnar light-transmitting container; 25-Top plate; 26-Folding frame; 27-Bottom frame; 28-Thrust cylinder; 29-Rotary motor; 30-Vertical gantry structure a; 31-Rotating shaft; 32-Gripper mechanism; 33-Base; 34-Screw sleeve; 35-Bolt; 36-Screw; 37-Vertical gantry structure b; 38-Lifting motor; 39-Central through hole. Detailed Implementation

[0045] Example 1

[0046] like Figures 3-8 As shown, this embodiment provides a three-dimensional sand molding device for calculating axial photocuring complex oil circuit pipelines, including an outer frame 11, a storage tank 8, a long cylindrical transparent container with constant curvature 24, a cylinder lifting mechanism 6, a CNC rotary table 9, a lifting and fixing mechanism 11, a laser projection device 3, a calibration camera 13, a C-type hot air mechanism 10, a cooling circuit pipeline 12, and an oxygen content monitoring and control mechanism 2. The long cylindrical transparent container with constant curvature 24 has a coaxial cylindrical cavity 23 in the middle. The cavity of the long cylindrical transparent container with constant curvature 24 has a U-shaped cross-section along the axial direction. The U-shaped cavity is connected to the storage tank 8 through a feeding pipe 17, which has a telescopic sleeve 7. The storage tank 8 is used to store the printing substrate 22. A red LED light 14 is provided on the top of the long cylindrical transparent container with constant curvature 24.

[0047] In the embodiment, the numerical control rotary table 9 comprises pneumatic clamps 21, a table box 18, a table motor 15, a worm 16, a turbine 19, a rotary table top 20 and a feeding pipe 17. The table motor 15 drives the worm 16 to rotate. Specifically, the table motor 15 drives the worm 16 to rotate through a transmission gear. The worm 16 is engaged with the turbine 19. The turbine 19 is horizontally arranged. The central shaft of the turbine 19 is fixedly connected with the rotary table top 20, so that the rotary table top 20 and the turbine 19 rotate synchronously. The rotary table top 20 is located above the table box 18. A plurality of pneumatic clamps 21 are arranged on the rotary table top 20. The pneumatic clamps 21 clamp and fix the long columnar transparent container 24 with equal curvature. The table box 18, the central shaft of the turbine 19 and the rotary table top 20 are provided with a central through hole 39 through which the feeding pipe 17 passes, so that the central through hole 39 communicates with the cavity of the U-shaped structure of the long columnar transparent container 24 with equal curvature. The table motor 15 drives the worm 16 to rotate.

[0048] In the embodiment, three independent pneumatic clamps 21 are arranged on the rotary table top 20. The pneumatic clamps 21 are driven by electromagnetic valves to clamp and fix the long columnar transparent containers 24 with equal curvature and different diameters.

[0049] In the embodiment, the pneumatic cylinder lifting mechanism 6 comprises a top plate 25 and a bottom frame 27. A folding frame 26 for lifting is slidingly arranged between the top plate 25 and the bottom frame 27. The folding frame 26 comprises two groups of symmetrically arranged X-shaped rotating shafts. The two groups of X-shaped rotating shafts are rotatably connected by two support shafts to form an X-shaped structure. A cross bar is connected between the two opposite support shafts of the two groups of X-shaped rotating shafts. A push cylinder 28 is arranged between the two cross bars. With the change of the length of the push cylinder 28, the two support shafts are rotated, so that the top plate 25 is lifted and lowered. The bottom frame 27 is fixed on the outer frame 1. The top plate 25 is fixed with the table box 18.

[0050] In the embodiment, the number of the pneumatic cylinder lifting mechanisms 6 is two groups, which are arranged on the left and right sides of the bottom of the table box 18. During work, the two groups of pneumatic cylinder lifting mechanisms push the numerical control rotary table 9 to rise until the rotary table top 20 contacts the bottom of the long columnar transparent container 24 with equal curvature. Then, the pneumatic clamps 21 are started to fix the bottom of the long columnar transparent container 24 with equal curvature.

[0051] In the embodiment, the lifting fixing mechanism 11 comprises a lead screw 36, a lead screw sleeve 34, a bolt 35, a vertical gantry structure a 30, a vertical gantry structure b 37, a base 33, a lifting motor 38, a rotating motor 29, a rotating shaft 31 and a jaw mechanism 32. The base 33 and the vertical gantry structure b 37 are both fixed on the outer frame 1. The lead screw 36 is vertically arranged between the base 33 and the vertical gantry structure b 37. The vertical gantry structure b 37 is provided with the lifting motor 38 which drives the rotation of the lead screw 36. The lead screw 36 is further provided with the lead screw sleeve 34. The lead screw sleeve 34 is fixed with the vertical gantry structure a 30 through the bolt 35. The vertical gantry structure a 30 is fixedly provided with the rotating motor 29. The rotating shaft 31 of the rotating motor 29 penetrates through the vertical gantry structure a 30 and is fixedly connected with the jaw mechanism 32. The rotation of the lead screw 36 is controlled by the lifting motor 38, so as to control the up-and-down movement of the lead screw sleeve 34 along the lead screw 36. The vertical gantry structure a 30 and the rotating motor 29 fixed on the lead screw sleeve 34 also realize the up-and-down movement, so as to realize the up-and-down movement of the jaw mechanism 32, which can clamp the top of the long columnar light-transmitting container 24 with equal curvature.

[0052] In the embodiment, the jaw mechanism 32 comprises a mounting seat and a plurality of jaws. The plurality of jaws are mounted on the mounting seat. The mounting seat is fixed on the rotating shaft 31. The plurality of jaws are used for clamping the long columnar light-transmitting container 24 with equal curvature. The rotating motor 29 drives the rotation of the rotating shaft 31 and the jaw mechanism 32. Meanwhile, the specific structure of the jaw mechanism 32 can also be other jaw mechanisms which can realize the function of clamping the top of the long columnar light-transmitting container 24 with equal curvature. There are many mature products on the market which can rotate. The specific structure of the jaw mechanism 32 is not the focus of the embodiment, and will not be described here in detail.

[0053] In the embodiment, the laser projection device 3 and the C-shaped hot air mechanism 10 are arranged on opposite sides of the long columnar light-transmitting container 24 with equal curvature. The air outlet of the C-shaped hot air mechanism 10 faces the long columnar light-transmitting container 24 with equal curvature. The air outlet of the C-shaped hot air mechanism 10 covers the whole long columnar light-transmitting container 24 with equal curvature as much as possible, so as to heat the printing medium in the long columnar light-transmitting container 24 with equal curvature. The lens 4 is arranged between the laser projection device 3 and the long columnar light-transmitting container 24 with equal curvature. The lens 4 is fixed by a support. The laser emitted by the laser projection device 3 converges on the printing medium 22 in the long columnar light-transmitting container 24 with equal curvature through the lens 4. The laser of the laser projection device 3 is aligned with the central axis of the long columnar light-transmitting container 24 with equal curvature. The calibration camera 13 is arranged on the other side of the long columnar light-transmitting container 24 with equal curvature. The calibration camera 13 is loaded with a red band-pass filter. The lens of the calibration camera 13 faces the central axis of the long columnar light-transmitting container 24 with equal curvature. The included angle between the laser projection device 3, the calibration camera 13 and the central axis of the long columnar light-transmitting container 24 with equal curvature is 90°.

[0054] In this embodiment, the wavelength of the light beam of the red LED lamp 14 is 678 nm, and the red light is outside the absorption band of the photoinitiator in the printing substrate 22, so it does not interfere with the forming process; the laser intensity of the laser projection device 3 is selected in the range of 0.5-6 mW / cm 2 , and the wavelength is 405 nm, emitting blue-violet light.

[0055] In this embodiment, the C-shaped hot air mechanism 10 includes a C-shaped vertically installed air plate, and a plurality of hot air blowers are installed on the air plate, and the hot air outlets of the hot air blowers are opposite to the long columnar light-transmitting container 24 with equal curvature. The thermocouple 5 is fixed at a position 3 mm away from the workbench box 18, which facilitates monitoring the blowing temperature of the C-shaped hot air mechanism 10.

[0056] In this embodiment, the cooling circuit pipeline 12 is arranged in the outer frame 1, and the cooling liquid flowing through the cooling circuit pipeline 12 cools the environment in the outer frame 1.

[0057] In this embodiment, the oxygen content monitoring and control mechanism 2 is arranged on the side wall of the outer frame 1, and the oxygen content monitoring and control mechanism 2 includes an oxygen content detector, a controller, and a nitrogen storage tank. The nitrogen storage tank is in communication with the inner cavity of the outer frame 1 through a nitrogen delivery pipe, and an electromagnetic valve is arranged on the nitrogen delivery pipe. The controller is electrically connected with the electromagnetic valve. The oxygen content detector is arranged inside the outer frame 1 to monitor the oxygen content in the environment of the whole outer frame 1, and the controller is used to control the oxygen content in the environment of the outer frame 1 to be less than 10%.

[0058] Embodiment 2

[0059] As shown in Figure 1 , the embodiment provides a method for stereolithography of an axial photocured complex oil pipeline sand mold, which comprises the following steps:

[0060] S1. Selecting a mixed formula of a printing substrate 22 according to a complex oil pipeline to be formed by axial photocuring, and placing the mixed formula in a storage box 8 after being uniformly mixed for standby use;

[0061] S2. Establishing an STL three-dimensional model of the complex oil pipeline sand mold by using software, and designing the size of a columnar cavity 23 in the long columnar light-transmitting container 24 according to the model;

[0062] S3. Dividing the structure layers from the center axis to the outermost layer and performing radial slicing on the geometric features of the complex oil pipeline sand mold STL three-dimensional model established in S2, and processing and analyzing the slicing data information, and loading the image sequence into a laser projection device after being sorted;

[0063] S4, the jaw mechanism 32 is used to clamp and fix the long columnar light-transmitting container 24 with equal curvature, the printing substrate 22 in the storage box 8 is sent into the U-shaped structure cavity of the long columnar light-transmitting container 24 with equal curvature through the feeding pipeline 17, and scattering calibration is performed; the scattering calibration is a pre-calibration of the projection laser intensity and other parameters by studying the scattering law before projection, so as to ensure that when the projection laser passes through the printing substrate 22 affected by the particle scattering and reaches the printing area, the laser intensity is sufficient to induce the printing substrate 22 to be cured and formed.

[0064] S5, the ambient temperature and atmospheric environment of the axial light-curing forming in the outer frame 1 are adjusted to a suitable state;

[0065] S6, the numerical control rotary table 9 is controlled by the cylinder lifting mechanism 6 to the bottom of the long columnar light-transmitting container 24 with equal curvature, and is fixed by using the pneumatic clamping jaw 21, then the rotating motor 29 is opened, the long columnar light-transmitting container 24 with equal curvature rotates around its axis in place, at the same time, the laser projection equipment is opened, and the pattern light containing the current structure layer slice information is projected into the printing substrate 22 after being adjusted by the lens 4;

[0066] S7, the red LED lamp 14 and the calibration camera 13 are opened for real-time calibration of spatial resampling, and the calibration information is fed back to adjust the projection parameters such as the laser intensity of the laser projection equipment in real time, the printing substrate 22 in the U-shaped structure cavity is gradually accumulated by the irradiation dose and causes volumetric curing and forming;

[0067] S8, the continuous projection and real-time calibration feedback during the curing and forming process are continued until the complex oil circuit pipeline printing piece is completed, the projection is stopped, the un-cured printing substrate 22 is cleaned and recycled, the complex oil circuit pipeline printing piece is taken out, and is placed and cured for 1-2 hours under the laser irradiation;

[0068] S9, whether the forming degree of the complex oil circuit pipeline printing piece meets the standard is judged, if not, repair and coating are performed, if yes, post-processing is performed, so that the complex oil circuit pipeline printing piece meets the required shape index and product delivery is performed.

[0069] In the embodiment, the crosslinking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylaminoethyl benzoate;

[0070] The photosensitive component and the sand material are mixed in a mass ratio of 6:4, the superfine fiber material is added in an amount not more than 2% of the total mass of the photosensitive component and the sand material for blending, the blending viscosity is at least 9000 mPa·s, and oscillation is performed to a bubble-free state to obtain the printing substrate 22;

[0071] The wavelength of the light beam of the red LED lamp 14 is 678 nm, and the laser intensity of the laser projection equipment is selected in the range of 0.5-6 mW / cm 2, wavelength is 405 nm; the time of laser irradiation curing forming should be controlled in 60~240s; the standing curing in S8 should be placed in 60℃ for 1~2h under 405nm laser irradiation;

[0072] The material of the equal-curvature long columnar light-transmitting container 24 is a light-transmitting material such as glass or crystal, and has a light transmittance of not less than 90% in the wavelength range of the projection light. The bottom inner cavity of the U-shaped structure cavity in the equal-curvature long columnar light-transmitting container 24 has a gap of at least 15 mm to facilitate feeding.

[0073] The forming environment temperature in S5 should be adjusted by the cooling loop pipeline 12 and the C-shaped hot air mechanism 10 respectively, and the adjustable temperature can be selected in the range of -15~160℃. The oxygen content in the atmosphere should be less than 10%.

[0074] Embodiment 3

[0075] The embodiment discloses a method for stereoscopic forming of an axial light-curing complex oil pipeline sand mold, and the method comprises the following steps:

[0076] S1, a mixed formula of a printing substrate 22 is selected according to a complex oil pipeline to be formed by axial light curing, and after being uniformly mixed, the printing substrate 22 is placed in a storage tank 8 for standby use. The printing substrate 22 comprises a sand mold material, a photosensitive component and an ultra-fine fiber material. The sand mold material is 8000-mesh powder quartz sand with a refractive index of 1.43. The photosensitive component is composed of a crosslinking agent and a photoinitiator. The crosslinking agent is polydimethyl acrylate and epoxy resin. The photoinitiator is camphorquinone and 4-dimethylamino benzoic acid ethyl ester. The ultra-fine fiber material is polyester. 60wt.% of the photosensitive component and 40wt.% of the sand mold material are mixed, and then 1% of the ultra-fine polyester fiber material based on the total mass of the photosensitive component and the sand mold material is added for adjustment. The adjustment viscosity is 10000 mPa·s, and the adjustment is oscillated to a bubble-free state to obtain the printing substrate 22.

[0077] The mass of the polydimethyl acrylate accounts for 17wt.% of the total mass of the sand mold material and the photosensitive component. The mass of the epoxy resin accounts for 23wt.% of the total mass of the sand mold material and the photosensitive component. The mass of the camphorquinone accounts for 11wt.% of the total mass of the sand mold material and the photosensitive component. The mass of the 4-dimethylamino benzoic acid ethyl ester accounts for 9wt.% of the total mass of the sand mold material and the photosensitive component.

[0078] S2, an STL three-dimensional model of the sand mold of the complex oil pipeline is established by using software. The thickness of the oil pipeline wall is designed to be 5 mm, and the outer diameter of the oil pipeline wall is designed to be 15 mm, as shown in Figure 2 (a), and the size of the columnar cavity 23 in the equal-curvature long columnar light-transmitting container 24 is designed according to the model. Specifically, the diameter of the equal-curvature long columnar light-transmitting container 24 is 60 mm, and the diameter of the columnar cavity 23 is 25 mm,

[0079] S3, the geometric features of the complex oil pipeline sand mold STL three-dimensional model established in S2 are divided into structural layers from the center axis to the outermost layer and radially sliced, and the sliced data information is processed and analyzed, and after being sorted into an image sequence, is loaded into a laser projection device;

[0080] S4, the equal-curvature long columnar light-transmitting container 24 is fixed by the clamping jaw mechanism 32, the printing substrate 22 in the storage box 8 is sent into the U-shaped structure cavity of the equal-curvature long columnar light-transmitting container 24 through the feeding pipeline 17, and scattering calibration is performed; after calibration, the laser projection device is put in, the maximum value of laser intensity is 1.82 mW / cm 2 , the minimum value of laser intensity is 0.42 mW / cm 2 ; the laser intensity is adjusted according to the complexity of the printed part, the light transmittance of the printing substrate, and the size of the printed part;

[0081] S5, the environmental temperature of the axial light-curing forming in the outer frame 1 is adjusted to 45℃, and the oxygen content is 8%;

[0082] S6, the numerical control rotary table 9 is controlled by the air cylinder lifting mechanism to the bottom of the equal-curvature long columnar light-transmitting container 24, and is fixed by the pneumatic clamping jaw 21, then the rotary motor 29 is opened, the container rotates around its axis at a speed of 20° / s, and at the same time, the laser projection device is opened, and the pattern light containing the current structural layer slice information is adjusted by the lens 4 and projected into the printing substrate 22;

[0083] S7, the red LED lamp 14 and the calibration camera 13 are opened for real-time calibration of spatial resampling, the calibration accuracy is 0.01, and the calibration information is fed back to adjust the laser intensity and other projection parameters of the laser projection device in real time, the irradiation amount of the printing substrate 22 in the U-shaped structure cavity gradually accumulates and causes volumetric solidification forming;

[0084] S8, during the solidification forming process, continuous projection and real-time calibration feedback are performed, until the complex oil pipeline printed part is completed, the projection is stopped, the un-solidified printing substrate 22 is cleaned and recycled, the complex oil pipeline printed part is taken out, and is placed at 60℃ for 2 hours under laser irradiation for solidification;

[0085] S9, whether the forming degree of the complex oil pipeline printed part meets the standard is judged, if not, repair coating is performed, if yes, post-processing is performed, so that the complex oil pipeline printed part meets the required shape index and product delivery is performed.

[0086] Example 4

[0087] The embodiment discloses a method for calculating axial light-curing complex oil pipeline sand mold three-dimensional forming, which comprises the following steps:

[0088] S1, select a mixed formula of the printing substrate 22 according to the complex oil pipeline to be axially photocured, mix uniformly and put into the storage tank 8 for standby; the printing substrate 22 comprises a sand material, a photosensitive component and an ultra-fine fiber material, the sand material is 8000 mesh powdery corundum sand with a refractive index of 1.53, the photosensitive component is composed of a crosslinking agent and a photoinitiator, the crosslinking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylaminoethyl benzoate; the ultra-fine fiber material is polyamide; 60wt.% of the photosensitive component and 40wt.% of the sand material are mixed, then 0.5% of the ultra-fine polyamide fiber material based on the total mass of the photosensitive component and the sand material is added for adjustment, the adjustment viscosity is 10000 mPa·s, and oscillation is performed until there is no air bubble, so as to obtain the printing substrate 22.

[0089] The mass of the polydimethyl acrylate accounts for 17wt.% of the total mass of the sand material and the photosensitive component, the mass of the epoxy resin accounts for 23wt.% of the total mass of the sand material and the photosensitive component, the mass of the camphorquinone accounts for 11wt.% of the total mass of the sand material and the photosensitive component, and the mass of the 4-dimethylaminoethyl benzoate accounts for 9wt.% of the total mass of the sand material and the photosensitive component;

[0090] S2, use software to establish a sand mold STL three-dimensional model of the complex oil pipeline, the designed oil pipeline wall thickness is 3mm, and the oil pipeline wall outer diameter is 10mm; 14mm; 15mm, as shown in Figure 2 (b), and the size of the cylindrical cavity 23 in the long cylindrical light-transmitting container 24 with equal curvature is designed according to the model; specifically, the long cylindrical light-transmitting container 24 with equal curvature has a diameter of 60mm, and the cylindrical cavity 23 has a diameter of 25mm,

[0091] S3, the geometric features of the sand mold STL three-dimensional model of the complex oil pipeline established in S2 are divided into structure layers from the center axis to the outermost layer and radially sliced, and the sliced data information is processed and analyzed, and after being arranged into an image sequence, is loaded into a laser projection device;

[0092] S4, the long cylindrical light-transmitting container 24 with equal curvature is fixed by using a clamping jaw mechanism 32, the printing substrate 22 in the storage tank 8 is sent into the U-shaped structure cavity of the long cylindrical light-transmitting container 24 with equal curvature through a feeding pipeline 17, and scattering calibration is performed; after calibration, the laser projection device is put in, the maximum value of the laser intensity is 1.74mW / cm 2 , and the minimum value of the laser intensity is 0.38mW / cm 2 ;

[0093] S5, the environmental temperature for the axial photocuring is adjusted to 34℃, and the oxygen content is 8%;

[0094] S6, adjust the cylinder lifting mechanism to control the numerical control rotary table 9 to the bottom of the equal curvature long columnar light-transmitting container 24, and use the pneumatic clamping jaw 21 to fix, then open the rotary motor 29, make the container rotate around its axis at a speed of 20 ° / s, and at the same time, open the laser projection device, and project the pattern light containing the current structure layer slice information into the printing substrate 22 after adjusting through the lens 4;

[0095] S7, open the red LED lamp 14 and calibrate the camera 13 to perform real-time calibration of spatial resampling, the calibration accuracy is 0.01, and the calibration information is fed back to adjust the laser intensity and other projection parameters of the laser projection device in real time, the printing substrate 22 in the U-shaped structure cavity gradually accumulates the irradiation amount and causes volumetric solidification forming;

[0096] S8, continue to project and feed back in real time during the solidification forming process, until the complex oil route pipeline printing piece is completed, stop projecting, clean and recycle the un-solidified printing substrate 22, take out the complex oil route pipeline printing piece, and place it under laser irradiation for 1.5 hours at 60 °C for solidification;

[0097] S9, judge whether the forming degree of the complex oil route pipeline printing piece meets the standard, if not, perform repair coating, if yes, perform post-processing, so that the complex oil route pipeline printing piece meets the required shape index and is delivered.

[0098] Example 5

[0099] The embodiment discloses a method for calculating the axial photocuring complex oil route pipeline sand mold three-dimensional forming method, which comprises the following steps:

[0100] S1, according to the complex oil route pipeline to be axially photocured and formed, a mixed formula of the printing substrate 22 is selected, and after being uniformly mixed, the printing substrate 22 is placed in the storage box 8 for standby use; the printing substrate 22 comprises a sand material, a photosensitive component and an ultra-fine fiber material, the sand material is 8000 mesh powdered quartz sand with a refractive index of 1.43, the photosensitive component is composed of a crosslinking agent and a photoinitiator, the crosslinking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylamino benzoic acid ethyl ester; the ultra-fine fiber material is polyester fiber; 60 wt.% of the photosensitive component and 40 wt.% of the sand material are mixed, then 1.8% of the ultra-fine polyester fiber material based on the total mass of the photosensitive component and the sand material is added for blending, the blending viscosity is 10000 mPa·s, and oscillation is performed until no air bubbles are generated, so as to obtain the printing substrate 22.

[0101] the mass of the polydiacrylic acid accounts for 17 wt.% of the total mass of the sand material and the photosensitive component, the mass of the epoxy resin accounts for 23 wt.% of the total mass of the sand material and the photosensitive component, the mass of the camphorquinone accounts for 11 wt.% of the total mass of the sand material and the photosensitive component, and the mass of the ethyl 4-dimethylaminobenzoate accounts for 9 wt.% of the total mass of the sand material and the photosensitive component;

[0102] S2, using software to establish the complex oil pipeline sand mold STL three-dimensional model, the designed oil pipeline wall thickness is 10 mm, the oil pipeline wall outer diameter is 30 mm, like Figure 2 (c), and the size of the cylindrical cavity 23 in the isocurvature long cylindrical light-transmitting container 24 is designed according to the model; specifically, the diameter of the isocurvature long cylindrical light-transmitting container 24 is 60 mm, and the diameter of the cylindrical cavity 23 is 0 mm,

[0103] S3, the geometric features of the complex oil pipeline sand mold STL three-dimensional model established in S2 are divided into structural layers from the center axis to the outermost layer and radially sliced, and the sliced data information is processed and analyzed, and after being sorted into an image sequence, it is loaded into a laser projection device;

[0104] S4, the isocurvature long cylindrical light-transmitting container 24 is fixed by using a clamping jaw mechanism 32, the printing substrate 22 in the storage tank 8 is sent into the U-shaped structure cavity of the isocurvature long cylindrical light-transmitting container 24 through the feeding pipeline 17, and scattering calibration is performed; after calibration, the laser projection device is put into the isocurvature long cylindrical light-transmitting container 24, and the maximum laser intensity is 3.62 mW / cm 2 , and the minimum laser intensity is 0.68 mW / cm 2 ;

[0105] S5, the environmental temperature for axial light-curing forming in the outer frame 1 is adjusted to 45℃, and the oxygen content is 8%;

[0106] S6, the numerical control rotary table 9 is controlled by the cylinder lifting mechanism to the bottom of the isocurvature long cylindrical light-transmitting container 24, and is fixed by using a pneumatic clamping jaw 21, then the rotating motor 29 is turned on, the container rotates around its axis at a speed of 15 / s, and at the same time, the laser projection device is turned on, and the pattern light containing the current structure layer slice information is adjusted by the lens 4 and projected into the printing substrate 22;

[0107] S7, the red LED lamp 14 and the calibration camera 13 are turned on for real-time calibration of spatial resampling, the calibration accuracy is 0.01, and the calibration information is fed back to adjust the laser intensity and other projection parameters of the laser projection device in real time, the irradiation amount of the printing substrate 22 in the U-shaped structure cavity gradually accumulates and causes volumetric solidification forming;

[0108] S8, continue to project and feedback in real time during the curing forming process until the complex oil circuit pipeline printing is completed, stop projecting, clean up and recycle the un-cured printing matrix 22, take out the complex oil circuit pipeline printing, and place it under laser irradiation for 2 hours of curing at 60℃;

[0109] S9, judge whether the forming degree of the complex oil circuit pipeline printing meets the standard, if not, carry out repair coating, if yes, carry out post-processing, so that the complex oil circuit pipeline printing meets the required shape index and product delivery is carried out.

[0110] Example 6

[0111] The embodiment discloses a method for calculating the axial light-curing complex oil circuit pipeline sand mold stereoscopic forming, which comprises the following steps:

[0112] S1, a mixed formula of a printing matrix 22 is selected according to the complex oil circuit pipeline to be axially light-cured and formed, and after being uniformly mixed, it is placed in a storage box 8 for standby use; the printing matrix 22 comprises a sand mold material, a photosensitive component and an ultra-fine fiber material, the sand mold material selects 8000-mesh powder-shaped ceramic sand with a refractive index of 1.53, the photosensitive component is composed of a crosslinking agent and a photoinitiator, the crosslinking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylamino benzoic acid ethyl ester; the ultra-fine fiber material selects polyamide fiber; 60wt.% of the photosensitive component and 40wt.% of the sand mold material are mixed, then 1.3% of the ultra-fine polyamide fiber material based on the total mass of the photosensitive component and the sand mold material is added for adjustment, the adjustment viscosity is 10000 mPa·s, and oscillation is performed until there is no air bubble, so as to obtain the printing matrix 22.

[0113] The mass of the polydimethyl acrylate accounts for 17wt.% of the total mass of the sand mold material and the photosensitive component, the mass of the epoxy resin accounts for 23wt.% of the total mass of the sand mold material and the photosensitive component, the mass of the camphorquinone accounts for 11wt.% of the total mass of the sand mold material and the photosensitive component, and the mass of the 4-dimethylamino benzoic acid ethyl ester accounts for 9wt.% of the total mass of the sand mold material and the photosensitive component;

[0114] S2, an STL three-dimensional model of the sand mold of the complex oil circuit pipeline is established by using software, the thickness of the oil circuit pipeline wall is designed to be 3mm, the outer diameter of the oil circuit pipeline wall is designed to be 10mm, as shown in Figure 2 (d), and the size of the columnar cavity 23 in the isocurvature long columnar light-transmitting container 24 is designed according to the model; specifically, the diameter of the isocurvature long columnar light-transmitting container 24 is 60mm, and the diameter of the columnar cavity 23 is 32mm,

[0115] S3, the geometric features of the STL three-dimensional model of the sand mold of the complex oil circuit pipeline established in S2 are subjected to structure layer division from the center axis to the outermost layer and radial slicing, and the slicing data information is processed and analyzed, and after being arranged into an image sequence, it is loaded into a laser projection device.

[0116] S4, the equal curvature long columnar light-transmitting container 24 is fixed by the clamping jaw mechanism 32, the printing substrate 22 in the storage box 8 is sent into the U-shaped structure cavity of the equal curvature long columnar light-transmitting container 24 through the feeding pipe 17, and scattering calibration is carried out; after calibration, the laser projection equipment is placed, the maximum value of laser intensity is 2.20 mW / cm 2 , the minimum value of laser intensity is 0.51 mW / cm 2 ; the forming environment temperature is adjusted,

[0117] S5, the environment temperature of the axial photocuring forming in the outer frame 1 is adjusted to 36℃, and the oxygen content is 8%;

[0118] S6, the numerical control rotary table 9 is controlled by the air cylinder lifting mechanism to the bottom of the equal curvature long columnar light-transmitting container 24, and is fixed by the pneumatic clamping jaw 21, then the rotating motor 29 is opened, the container rotates around its axis at a speed of 18° / s, at the same time, the laser projection equipment is opened, and the pattern light containing the current structure layer slice information is projected into the printing substrate 22 after being adjusted by the lens 4;

[0119] S7, the red LED lamp 14 and the calibration camera 13 are opened for real-time calibration of spatial resampling, the calibration accuracy is 0.01, and the calibration information is fed back to adjust the laser intensity and other projection parameters of the laser projection equipment in real time, the printing substrate 22 in the U-shaped structure cavity is gradually accumulated by the irradiation amount and causes volumetric solidification forming;

[0120] S8, during the solidification forming process, the projection and real-time calibration feedback are continued until the complex oil road pipe printing piece is completed, the projection is stopped, the un-solidified printing substrate 22 is cleaned and recycled, the complex oil road pipe printing piece is taken out, and is placed at 60℃ for 2 hours under laser irradiation for solidification;

[0121] S9, whether the forming degree of the complex oil road pipe printing piece meets the standard is judged, if not, repair coating is carried out, if yes, post-processing is carried out, so that the complex oil road pipe printing piece meets the required shape index and product delivery is carried out.

[0122] The above is only a preferred embodiment of the present application, and does not limit the present application. Any simple modification, change and equivalent change of the above embodiment according to the technical essence of the present application still belongs to the protection scope of the technical scheme of the present application.

Claims

1. A device for stereolithography of complex axial light-cured oil ducts in sand molds, characterized in that, The application relates to a 3D printing device, which comprises an outer frame (1), a storage box (8), an equal-curvature long-columnar light-transmitting container (24), a cylinder lifting mechanism (6), a numerical control rotary workbench (9), a lifting fixing mechanism (11), a laser projection device (3), a calibration camera (13), a C-shaped hot air mechanism (10), a cooling loop pipeline (12) and an oxygen content monitoring control mechanism (2); the cylinder lifting mechanism (6), the numerical control rotary workbench (9), the lifting fixing mechanism (11), the laser projection device (3), the calibration camera (13), the C-shaped hot air mechanism (10) and the cooling loop pipeline (12) are arranged in the outer frame (1), the oxygen content monitoring control mechanism (2) is arranged on the outer frame (1), and the storage box (8) is arranged outside the outer frame (1); a coaxial columnar cavity (23) is arranged in the middle of the equal-curvature long-columnar light-transmitting container (24), the cavity of the equal-curvature long-columnar light-transmitting container (24) is in a U-shaped structure in the axial section, the U-shaped structure cavity is communicated with the storage box (8) through a feeding pipeline (17), the storage box (8) is used for storing a printing matrix (22), and a red LED lamp (14) is arranged at the top of the equal-curvature long-columnar light-transmitting container (24); The numerical control rotary workbench (9) comprises pneumatic clamps (21), a workbench box body (18), a workbench motor (15), a worm (16), a turbine (19), a rotating table top (20) and the feeding pipeline (17); the workbench motor (15) drives the worm (16) to rotate, the worm (16) is engaged with the turbine (19), the turbine (19) is horizontally arranged, the central shaft of the turbine (19) is fixedly connected with the rotating table top (20), the rotating table top (20) is synchronously rotated with the turbine (19), the rotating table top (20) is arranged above the workbench box body (18), a plurality of groups of pneumatic clamps (21) are arranged on the rotating table top (20) and are used for clamping and fixing the bottom of the equal-curvature long-columnar light-transmitting container (24), central through holes (39) of the workbench box body (18), the central shaft of the turbine (19) and the rotating table top (20) are provided with the feeding pipeline (17), so that the U-shaped structure cavity of the equal-curvature long-columnar light-transmitting container (24) is communicated; and the workbench motor (15) drives the worm (16) to rotate; The cylinder lifting mechanism (6) is arranged between the outer frame (1) and the numerical control rotary workbench (9); The lifting fixing mechanism (11) is arranged on the side of the equal-curvature long-columnar light-transmitting container (24), a rotating motor (29) and a clamping jaw mechanism (32) are arranged on the lifting fixing mechanism (11) and located above the equal-curvature long-columnar light-transmitting container (24), the rotating shaft (31) of the rotating motor (29) is downwardly connected with the clamping jaw mechanism (32), and the clamping jaw mechanism (32) is used for clamping the top of the equal-curvature long-columnar light-transmitting container (24); The laser projection device (3) and the C-shaped hot air mechanism (10) are respectively arranged on opposite sides of the equal-curvature long columnar light-transmitting container (24), the air outlet of the C-shaped hot air mechanism (10) faces the equal-curvature long columnar light-transmitting container (24), and the C-shaped hot air mechanism (10) is used for heating the printing substrate (22) in the equal-curvature long columnar light-transmitting container (24); a lens (4) is further arranged between the laser projection device (3) and the equal-curvature long columnar light-transmitting container (24), the lens (4) is fixed through a support, the laser projection device (3) emits laser which converges on the printing substrate (22) in the equal-curvature long columnar light-transmitting container (24) through the lens (4); the laser of the laser projection device (3) is aligned with the central axis of the equal-curvature long columnar light-transmitting container (24), and a calibration camera (13) is arranged on the other side of the equal-curvature long columnar light-transmitting container (24); the calibration camera (13) is loaded with a red band-pass filter, the lens of the calibration camera (13) faces the central axis of the equal-curvature long columnar light-transmitting container (24), and the included angle between the laser projection device (3), the calibration camera (13) and the central axis of the equal-curvature long columnar light-transmitting container (24) is 90°.

2. The apparatus for stereolithography of complex axial light-cured oil channel pipes according to claim 1, wherein, The air cylinder lifting mechanism (6) comprises a top plate (25) and a bottom frame (27), a folding frame (26) for lifting is slidingly arranged between the top plate (25) and the bottom frame (27), the folding frame (26) comprises two groups of symmetrically arranged X-shaped rotating shafts, the two groups of symmetrically arranged X-shaped rotating shafts are rotationally connected by two support shafts to form an X-shaped structure, a cross bar is connected between the two opposite support shafts of the two groups of X-shaped rotating shafts, a thrust cylinder (28) is arranged between the two cross bars, and the rotation of the two support shafts is realized by changing the length of the thrust cylinder (28), so that the top plate (25) is lifted and lowered, the bottom frame (27) is fixed on the outer frame (1), and the top plate (25) is fixed with the workbench box body (18).

3. The apparatus according to claim 1, wherein, The lifting fixing mechanism (11) comprises a lead screw (36), a lead screw sleeve (34), a bolt (35), a vertical gantry structure a (30), a vertical gantry structure b (37), a base (33) and a lifting motor (38); the base (33) and the vertical gantry structure b (37) are fixed on the outer frame (1), the lead screw (36) is vertically rotationally arranged between the base (33) and the vertical gantry structure b (37), the vertical gantry structure b (37) is provided with the lifting motor (38) which drives the rotation of the lead screw (36), the lead screw (36) is further provided with the lead screw sleeve (34), the lead screw sleeve (34) and the vertical gantry structure a (30) are fixed by the bolt (35), the vertical gantry structure a (30) is fixedly provided with a rotating motor (29), and the rotating shaft (31) of the rotating motor (29) penetrates through the vertical gantry structure a (30) and is connected with the clamping jaw mechanism (32) downward.

4. The apparatus according to claim 1, wherein, The C-shaped hot air mechanism (10) comprises a C-shaped structure vertically installed air plate, a plurality of hot air machines are installed on the air plate, and the hot air outlet of the hot air machine is opposite to the equal-curvature long columnar light-transmitting container (24); the thermocouple (5) is fixed at a position 3mm away from the workbench box (18); and the cooling loop pipeline (12) is arranged in the outer frame (1).

5. The apparatus according to claim 1, wherein, The oxygen content monitoring control mechanism (2) is arranged on the side wall of the outer frame (1), and comprises an oxygen content detector, a controller and a nitrogen storage tank. The nitrogen storage tank is communicated with the inner cavity of the outer frame (1) through a nitrogen conveying pipe, an electromagnetic valve is arranged on the nitrogen conveying pipe, the controller is electrically connected with the electromagnetic valve, the oxygen content detector is arranged on the inner side of the outer frame (1), the oxygen content in the environment in the whole outer frame (1) is monitored, and the oxygen content in the environment in the outer frame (1) is controlled to be not more than 10% through the controller.

6. A method for fabricating an axial light-cured complex channel pipe sand mold using the forming device according to any one of claims 1 to 5, wherein, The method comprises: S1, selecting a mixed formula of a printing substrate (22) according to a complex oil pipeline to be axially photo-cured, and placing the printing substrate (22) in a storage box (8) after being uniformly mixed for standby; S2, establishing a sand mold STL three-dimensional model of the complex oil pipeline by using software, and designing the size of a columnar cavity (23) in the equal-curvature long columnar light-transmitting container (24) according to the model; S3, dividing the structure layer from the center axis to the outermost layer and performing radial slicing on the geometric features of the complex oil pipeline sand mold STL three-dimensional model established in S2, and after the slicing data information is processed and analyzed and is arranged into an image sequence, the image sequence is loaded into a laser projection device; S4, clamping and fixing the equal-curvature long columnar light-transmitting container (24) by using a clamping jaw mechanism (32), the printing substrate (22) in the storage box (8) is sent into a U-shaped structure cavity of the equal-curvature long columnar light-transmitting container (24) through a feeding pipeline (17), and scattering calibration is performed; the scattering calibration is a pre-calibration on the projection laser intensity and other parameters by studying the scattering law before projection, so that when the projection laser passes through the printing substrate (22) and reaches the printing area after being affected by the particle scattering, the laser intensity is sufficient to induce the printing substrate (22) to be cured and formed; S5, adjusting the environmental temperature and atmosphere of the axial photo-cured forming in the outer frame (1) to a suitable state; S6, adjusting the air cylinder lifting mechanism (6) to control the numerical control rotary workbench (9) to the bottom of the equal-curvature long columnar light-transmitting container (24), and fixing by using a pneumatic clamping jaw (21), then opening the rotary motor (29), so that the equal-curvature long columnar light-transmitting container (24) rotates around its axis, and at the same time, the laser projection device is started, and the pattern light containing the current structure layer slicing information is projected into the printing substrate (22) after being adjusted by the lens (4); S7, starting the red LED lamp (14) and the calibration camera (13) to perform real-time calibration of space resampling, and feeding back the calibration information to adjust the laser intensity and other projection parameters of the laser projection device in real time, the printing substrate (22) in the U-shaped structure cavity gradually accumulates the irradiation amount and causes volumetric curing and forming. S8, continue to project and real-time calibration feedback in the curing forming process until the complex oil circuit pipeline printing piece is completed, stop projecting, clean and recycle the un-cured printing matrix (22), take out the complex oil circuit pipeline printing piece, and place it under laser irradiation for curing; S9, judge whether the forming degree of the complex oil circuit pipeline printing piece meets the standard after curing, if not, carry out repair coating, if it meets the standard, carry out post-processing, so that the complex oil circuit pipeline printing piece meets the required shape index and product delivery.

7. The method of claim 6, wherein, The preparation method of the printing matrix (22) is: mixing photosensitive components and sand materials according to a mass ratio of 6:4, then adding not more than 2% of superfine fiber materials of the total mass of the photosensitive components and sand materials for blending, the blending viscosity is at least 9000 mPa·s, and oscillation is carried out until no bubbles are generated to obtain the printing matrix (22); The mesh number of the sand material can be selected in the range of 2000-8000 meshes, the sand material is in a powder state, and is subjected to fluidization treatment to obtain a sand material with liquid fluidity before mixing and blending; The photosensitive component is composed of a crosslinking agent and a photoinitiator, the crosslinking agent is polydimethyl acrylate and epoxy resin, and the photoinitiator is camphorquinone and 4-dimethylaminoethyl benzoate.

8. The method of claim 6, wherein, The wavelength of the red LED light beam is 678nm; the laser intensity of the laser projection device (3) is selected in the range of 0.5-6mW / cm 2 , and the wavelength is 405nm; the time for laser irradiation and solidification forming should be controlled in the range of 60-240s.

9. The method of claim 6, wherein, In S8, the curing is carried out under 405 nm laser irradiation and at a temperature of 60℃ for 1-2 h.

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