Columnar 3D printing equipment and 3D printing method thereof

Abstract

The invention discloses cylindrical 3D printing equipment and a 3D printing method thereof.The equipment comprises a cylindrical printing platform, a printing spray head, a forming auxiliary device and a moving structure, the cylindrical printing platform rotates along the axis of the cylindrical printing platform through a printing platform driving motor, and the printing spray head sprays a printing material to the side face of the cylindrical printing platform; the side face is a printing face, the forming auxiliary device conducts forming assistance on a printing material on the side face, and the side face can move by a set distance relative to the printing spray head and the forming auxiliary device through the moving structure. The forming auxiliary device is simpler in design, can greatly reduce the non-jet invalid motion time, improves the proportion of the jet time in the whole printing time, can generate a series of concentric cylindrical slice files, can realize continuous jet printing of one layer of data files, eliminates invalid motion in plane reciprocating motion, and improves the printing efficiency. And the printing efficiency is greatly improved.

Description

Technical Field

[0001] This invention pertains to 3D printing, specifically relating to a cylindrical 3D printing device and its 3D printing method. Background Technology

[0002] The working principle of MJP (Modular Jet Printing) 3D printers is relatively simple yet highly efficient. First, the printer calculates the quantity and location of structural and support materials to be sprayed for each layer based on the input 3D model data. Then, by controlling the movement and spray volume of multiple nozzles, liquid photosensitive resin or phase change materials (especially wax-based materials) are precisely sprayed onto the printing platform. After each layer is sprayed, the printing platform moves a certain distance relative to the multi-nozzle head to begin the spraying and curing process for the next layer. Finally, through layer-by-layer accumulation and curing, a complete 3D printed model is obtained. This technology is not limited to printing photosensitive resins but can also print casting wax. Therefore, MJP wax-spraying printers are widely used in various fields, including jewelry design, industrial design, medical devices, and aerospace. In the field of jewelry design, MJP (Modulated Jet Printing) wax printers can print high-precision, complex jewelry models. In the field of industrial design, they can be used to create high-precision prototypes and molds. In the aerospace field, they can be used to create complex aircraft parts and engine components. Existing MJP printers, such as the ProJet MJP 2500W 3D printer from 3D Systems, primarily use real wax materials for printing, directly producing high-precision and detailed wax models. They employ a flat rectangular printing platform. During the printing process, the nozzle moves from one side of the printing platform to the other, simultaneously spraying wax, and then returns to the other side. In this reciprocating motion, spraying only occurs when passing through the printing area. The effective spraying time accounts for a relatively low proportion of the total printing time, resulting in low printing efficiency.

[0003] For example, patent CN107980022A discloses a device with a disc-shaped printing platform. The disc-shaped printhead rotates, which is equivalent to the X-axis movement in the above scheme. Its advantage lies in the fact that the rotational movement replaces the linear reciprocating motion, thus improving efficiency. The printhead moves radially along the disc, which is equivalent to the Y-axis movement. The problem is that the linear velocities on the inner and outer sides of the disc are different. As described in the specification, "the controller is configured to compensate for multiple errors in the radial position of the inkjet printhead according to a compensation function," which does not fully utilize the printhead's ejection frequency. The printing process needs to stop ejection at certain positions. After printing one layer, the disc-shaped printhead moves a point along the Z-axis until the entire model is printed.

[0004] The disc-shaped printing platform continuously ejects ink as it rotates. The linear velocity near the center of the disc is significantly different from that near the edge. The same printhead cannot achieve different ejection frequencies on both sides, making printhead control complex and failing to fully utilize the printhead's ejection frequency performance. The mechanism for smoothing the ejected material is also relatively complex. A printer that rotates on a flat surface is large in size and has a complex motion mechanism, which presents certain disadvantages.

[0005] Patent US11104076B2 discloses a printing model forming process. The printhead moves along an axis, scanning simultaneously. The printhead is responsible for movement in the X-axis and Y-axis, while the printing platform is responsible for movement in the Z-axis. The printhead ejects some ink along the X-axis once, then moves a little along the Y-axis. This cycle repeats until one layer is printed. The printing platform then moves a little along the Z-axis, and the printhead repeats the X and Y-axis movements of the previous layer until the entire model is printed.

[0006] The printhead moves back and forth on both sides of a flat platform, but it only ejects ink when it reaches the printing area. The effective ink ejection time is a small percentage of the overall process, resulting in low printing efficiency. Furthermore, when reversing direction, the printer controls the motor to accelerate and decelerate, further reducing printing efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a cylindrical 3D printing device and its 3D printing method, which can greatly reduce non-jetting ineffective motion time, increase the proportion of jetting time in the overall printing time, generate a series of concentric cylindrical sheet file slices, and achieve continuous jetting printing of a single layer of data file, thus greatly improving printing efficiency. To achieve the above objectives, this invention adopts the following technical solution:

[0008] A cylindrical 3D printing device includes a cylindrical printing platform, a printing nozzle, and a moving structure. The cylindrical printing platform can rotate around the axis of the column. The printing nozzle is arranged opposite to the side of the cylindrical printing platform. The printing nozzle is used to spray printing material onto the side, which is the printing surface. The side can move a set distance relative to the printing nozzle through the moving structure.

[0009] Furthermore, it also includes a forming aid device, which is located behind the print head and is used to assist in forming the printing material. The forming aid device is set opposite to the side, and the side of the movable structure can move a set distance relative to the print head and the forming aid device.

[0010] Furthermore, using the radial projection of the cylindrical 3D printing equipment onto the cylindrical printing platform as a definition, the axis of the cylindrical printing platform is point A, the ejection center of the printing nozzle is point B, and the center of the forming assistance of the forming auxiliary device is point C. The moving structure drives the cylindrical printing platform to move away from the printing nozzle along the angle bisector of ∠BAC; or, the moving structure drives the forming auxiliary device to move away from the cylindrical printing platform along the extension of AC, and the moving structure drives the printing nozzle to move away from the cylindrical printing platform along the extension of AB.

[0011] Furthermore, it also includes a printhead mounting base, which is equipped with a printhead motion mechanism. While the cylindrical printing platform rotates around the axis of the column, the printhead motion mechanism drives the printhead to move linearly along a line parallel to the axis of the column. After the printhead moves from the first end to the second end of the cylindrical printing platform, the cylindrical printing platform moves away from the printhead by a printing layer thickness through a moving structure.

[0012] Furthermore, the moving structure is a printing platform moving mechanism, which includes a lead screw motor, a slide rail, and a slider. The lead screw motor is connected to the slide rail for transmission, and the slider slides in cooperation with the slide rail. The slider is connected to a fixed seat, and the fixed seat is connected to the cylindrical printing platform. The lead screw motor drives the cylindrical printing platform to move along the slide rail, and the slide rail is parallel to the angle bisector of ∠BAC.

[0013] Furthermore, the printhead mounting base is connected to a forming auxiliary device, which includes a flattening device located behind the printhead for flattening the printing material. The flattening device includes a flattening roller and a flattening motor that drives the flattening roller to rotate. The flattening roller spans the entire side and its length is greater than the effective printing length of the column printing platform. The column printing platform and the flattening roller always maintain their original rotation direction.

[0014] Furthermore, the molding auxiliary device also includes a UV curing device, which is located behind the planarization device and is used to UV cure the printing material.

[0015] Furthermore, the printhead mounting base is connected to a molding auxiliary device, which includes a UV curing device located behind the printhead for UV curing of the printing material.

[0016] Furthermore, the cylinder printing platform includes a cylindrical printing platform, a polygonal prism printing platform, or an elliptical cylinder printing platform, etc. Preferably, the polygonal prism is a regular polygonal prism with 6 or more edges.

[0017] A 3D printing method using a cylindrical 3D printing device includes the following steps:

[0018] (1) Generate a series of concentric cylindrical sheet files: Import the data model file to be printed into the software, create concentric cylindrical cutting surfaces, cut the concentric cylindrical cutting surfaces and data model files into a series of concentric cylindrical sheet files and transfer them to the cylindrical 3D printing equipment.

[0019] (2) Print 3D models according to a series of concentric cylindrical sheet files: While the cylindrical printing platform rotates, the printing nozzle moves in a straight line along the parallel line of the axis of the cylindrical printing platform and sprays printing. The forming auxiliary device assists in forming. Whenever the printing nozzle moves from the first end to the second end of the cylindrical printing platform, the moving structure drives the cylindrical printing platform away from the printing nozzle by a distance of one printing layer thickness along the angle bisector of ∠BAC. The printing nozzle moves in a straight line in the opposite direction to print until printing is completed.

[0020] Furthermore, in step (1), the specific method for importing the data model file to be printed into the software is as follows: send the data model file to be printed to the model data layout software, place the model file to be printed on the column printing platform virtually presented by the computer software, and according to the user's requirements for placement direction and position, generate support along the radial direction of the column printing platform and the projection direction towards the axis of the column printing platform for the model placed on the column printing platform, and generate the corresponding support to form the model layout file.

[0021] Furthermore, in step (1), the specific method for establishing the concentric cylindrical cutting surface is as follows: the radius of the concentric cylindrical cutting surface gradually increases according to the layer thickness r, that is, the radius of the next concentric cylindrical cutting surface is larger than the previous concentric cylindrical cutting surface by a printing layer thickness r, and the axial length of the concentric cylindrical cutting surface is equal to the effective printing length of the cylindrical printing platform.

[0022] Furthermore, in step (2), the radius of the column printing platform is R, and the starting position of the printing nozzle is at a certain height h above the printing platform, that is, the distance between the nozzle and the axis of the column printing platform is R+h.

[0023] Furthermore, in step (2), as the number of printing layers increases, the angular velocity of the column printing platform remains constant, while the linear velocity at the location of the printing surface gradually increases, thereby gradually increasing the ejection frequency of the nozzle.

[0024] Furthermore, in step (2), as the number of printing layers increases, the angular velocity of the column printing platform is controlled to gradually decrease, so as to ensure that the linear velocity of the printing surface remains unchanged, and the spraying frequency of the nozzle remains unchanged.

[0025] By adopting the above technical solution, the present invention has the following beneficial effects:

[0026] 1. It can generate a series of concentric cylindrical layer slice files. The nozzle moves in a cylindrical spiral with equal diameter relative to the cylindrical printing platform, which can realize continuous jet printing of one layer of data file, eliminate the invalid movement in planar reciprocating motion, and greatly improve printing efficiency.

[0027] 2. The relative reciprocating motion of the printing platform and the printhead in the existing technology is changed to the relative unidirectional rotational motion of the cylindrical printing platform and the printhead, which avoids the difficulty of aligning the landing points during reciprocating printing.

[0028] 3. It can simultaneously and equidistantly move away from the nozzle and molding auxiliary device, simplifying the mechanical structure and making the structural layout easier and more reasonable.

[0029] 4. Because the support data generated by the placed model is radially generated along the column printing platform, centripetal support is generated. Compared with the support generated by the downward plumb line, more models can be placed in the same printing area, and less support material can be used.

[0030] 5. The column printing platform and forming auxiliary device can achieve continuous leveling without changing direction during the entire printing process.

[0031] 6. It can make the layout of the molding auxiliary device more reasonable, and more processing devices can be conveniently arranged around the column printing platform, such as adding a UV light source to realize MJP light curing printing, making expansion more convenient and the usage efficiency higher. Attached Figure Description

[0032] The invention will now be further described with reference to the accompanying drawings.

[0033] Figure 1 This is a perspective view of a cylindrical 3D printing device according to Example 1.

[0034] Figure 2 for Figure 1 A three-dimensional view from another angle.

[0035] Figure 3 This is a front view of a cylindrical 3D printing device according to Embodiment 1.

[0036] Figure 4 This is a schematic diagram of the printing nozzle, planarization device, and cylindrical printing platform of Example 1.

[0037] Figure 5 This is a schematic diagram of the model layout file for Example 1.

[0038] Figure 6 This is a schematic diagram of a concentric cylindrical continuous sheet file from Example 1.

[0039] Figure 7 This is a diagram showing the movement trajectory of the printhead around the cylindrical printing platform in Example 1.

[0040] Figure 8 This is a perspective view of a 3D printing device according to Example 2.

[0041] Figure 9 This is a schematic diagram of the model layout file for Example 2.

[0042] Figure 10 This is a schematic diagram of the movement trajectory of the print head around the polygonal prism printing platform in Example 2. Detailed Implementation

[0043] Example 1

[0044] like Figures 1-4 An embodiment of a cylindrical 3D printing device is shown, comprising a cylindrical printing platform 1, a printing nozzle 2, a forming auxiliary device, a printing platform moving structure, and a mounting base 15. Specifically, the cylindrical printing platform 1 is a circular printing platform 1, comprising two parallel circular bottom surfaces and one side surface 6. The mounting base 15 is provided with a nozzle fixing seat 16, which is equipped with a printing nozzle moving mechanism 11. The printing nozzle moving mechanism 11 drives the printing nozzle 2 to move linearly along a line parallel to the axis of the cylindrical printing platform 1. In this embodiment, the forming auxiliary device is a planarization device 3, which can be a leveling roller 31 or a scraper (not shown in the figure), etc. The planarization device 3 and the printing nozzle 2 are both fixed to the nozzle fixing seat 16 and maintained at a certain distance.

[0045] The mounting base 15 is provided with a printing platform fixing seat 4. The printing platform fixing seat 4 is fixed with a printing platform moving structure. The printing platform moving structure includes a lead screw motor 7, a slide rail 8 and a slider 9. The lead screw motor 7 is connected to the slide rail 8 and drives the slide rail 8 to move. The slider 9 slides in cooperation with the slide rail 8. The slider 9 is connected to a fixing seat 10. The fixing seat 10 is connected to the cylindrical printing platform 1. The lead screw motor 7 drives the cylindrical printing platform 1 to move along the slide rail 8.

[0046] The cylindrical printing platform 1 is driven by the printing platform drive motor 5 to rotate around its axis 19. The print head 2 sprays printing material onto the side surface 6 of the cylindrical printing platform 1, which is the printing surface. The planarization device 3 includes a leveling roller 31 and a leveling motor 32 that drives the leveling roller to rotate. The leveling roller 31 is located behind the print head 1, where "behind" refers to relative to the rotation direction of the cylindrical printing platform 1. At a certain point on the side surface 6 of the cylindrical printing platform 1, the material passes the print head 1 first and then the leveling roller 31. This arrangement allows for material spraying followed by leveling. The rotation direction of the leveling roller 31 is opposite to that of the cylindrical printing platform 1, or, if there is a sufficient difference in linear velocity, the same. The leveling roller 31 is positioned along a line parallel to the axis of the cylindrical printing platform 1, spanning the entire side surface 6, and its length is greater than the effective printing length L of the cylindrical printing platform 1. This eliminates the need for the leveling roller 31 to move along the axis of the cylindrical printing platform 1, reducing structural complexity.

[0047] like Figure 3 As shown, the cylindrical 3D printing equipment is defined by its radial projection onto the cylindrical printing platform 1. Point A is the axis of the cylindrical printing platform 1, point B is the ejection center of the printing nozzle 2, and point C is the leveling center of the planarization device 3. The printing platform moving structure drives the cylindrical printing platform 1 to move away from the planarization device 3 and the printing nozzle along the angle bisector AD of ∠BAC. The slide rail 8 is parallel to the angle bisector AD of ∠BAC. In reality, from a three-dimensional structural perspective, points A, B, and C are all lines, while the angle bisector of ∠BAC is a plane; this is just a simplified explanation. Alternatively, the planarization device 3 can move away from the cylindrical printing platform 1 along the extension of AC, and the printing nozzle can move away from the cylindrical printing platform 1 along the extension of AB. However, this structure is slightly more complex and requires an additional moving mechanism.

[0048] A 3D printing method using a cylindrical 3D printing device includes the following steps:

[0049] 1. Generate a series of concentric cylindrical layer files:

[0050] 1.1 The specific method for importing the data model file to be printed into the software is as follows: Send the data model file to be printed to the model data layout software. Place the model file to be printed on the cylindrical printing platform 1 virtually rendered by the computer software. According to the user's requirements for placement direction and position, for the model placed on the cylindrical printing platform 1, generate supports 17 along the radial direction of the cylinder, towards the projection direction of the axis of the cylindrical printing platform 1, and generate corresponding supports 17 to form the model layout file, such as... Figure 5 As shown.

[0051] In other words, taking one of the 3D models 18 as an example, the support 17 is within the angle range α covered by the line connecting the maximum radial width of the model and the axis, such as... Figure 6 As shown by the dashed line, the centripetal support, compared to the downward support generated by the plumb bob, allows for the placement of more models within the same printing area, and reduces the amount of support material used.

[0052] 1.2 The radius of the concentric cylindrical cutting surface 12 gradually increases with the printing layer thickness r, that is, the radius of the next concentric cylindrical cutting surface is larger than the radius of the previous concentric cylindrical cutting surface by a printing layer thickness r. The axial length of the concentric cylindrical cutting surface is the same as the effective printing length L of the cylindrical printing platform.

[0053] 1.3 such as Figure 6 As shown, the concentric cylindrical cutting surface 12 and the data model file are cut into a series of concentric cylindrical sheet files, and the series of concentric cylindrical sheet files are transferred to the cylindrical 3D printing equipment.

[0054] 2. Print 3D model 18 based on a series of concentric cylindrical sheet files:

[0055] 2.1 The cylindrical printing platform 1 has a radius of R. The initial positions of the printing nozzle 2 and the leveling roller 31 are at a certain height h above the side 6 of the cylindrical printing platform 1. When printing the first layer, printing begins at a position where the distance between the printing nozzle 2 and the axis of the cylindrical printing platform 1 is R+h. The thickness of each layer is r. During printing, the layer file closest to the innermost cylindrical printing platform 1 is printed.

[0056] 2.2 The cylindrical printing platform 1 rotates around its axis under the action of the drive motor 5. At the same time, the printing nozzle 2 moves at a constant speed in a straight line along the parallel line (i.e., the Z-axis) of the axis 19 of the cylindrical printing platform 1 and sprays printing. The leveling roller 31 rotates in the opposite direction to the cylindrical printing platform 1. Each time the printing nozzle 2 moves from the first end to the second end of the side 6 of the cylindrical printing platform 1, the printing of one layer of sheet document is completed.

[0057] The speed of the print head 2's uniform linear motion should not be too fast and needs to be calculated based on the print head's spray resolution and the set print resolution. For example, if the print resolution is set to 500 dpi and the print head's spray resolution is 100 dpi, the distance between two adjacent nozzles is 0.254 mm. To fill the distance between the two nozzles, the print head needs to move several times. The number of moves is called the pass count. The pass count = print resolution DPI / print head spray resolution DPI = 5 times. That is, when the cylindrical printing platform 1 rotates 360°, the print head 2 moves a distance along the parallel line of the axis 19 of the cylindrical printing platform 1 = the distance between two adjacent nozzles / pass count = 0.254 / 5 = 0.0508 mm. When the cylindrical printing platform 1 completes 5 360° rotations, the print head 2 moves one nozzle spacing along the parallel line of the axis 19 of the cylindrical printing platform 1. The above is just an example of the print head 2's movement speed and is not limited to this example.

[0058] The printing platform moving structure drives the cylindrical printing platform 1 to move a distance of one printing layer thickness r along the angle bisector AD of ∠BAC away from the printing nozzle 2, i.e., the distance between the printing nozzle 2 and the axis of the cylindrical printing platform 1 is R+h+r. The printing nozzle 2 moves in the opposite direction from the second end back to the first end for printing. At this time, the cylindrical printing platform 1 and the leveling roller 31 still maintain their original rotation direction to complete the printing of the next layer of the file; and so on, until printing is completed, generating the support 17 and the 3D model 18. During the printing process, the cylindrical printing platform 1 can continuously rotate in the same direction without the reverse movement required by the traditional planar printing platform with linear planar motion. It can support continuous rotation printing within the same slice file, greatly improving printing efficiency. In addition, the leveling roller 31 can also maintain rotation in the same direction, and the leveling roller 31 can always level the sprayed material.

[0059] The trajectory diagram of the print head 2 moving around the cylindrical printing platform 1 is shown below. Figure 6 As shown, dashed line 13 represents the trajectory of print head 2 when printing the first layer, i.e., the initial layer, and solid line 14 represents the trajectory of print head 2 when printing the second layer. When printing the initial layer, it can usually be printed closer to the cylindrical printing platform 1. When printing the second, third, and subsequent layers, the layer thickness can be appropriately increased relative to the initial layer.

[0060] Example 2

[0061] See Figures 8-10This is another embodiment of a cylindrical 3D printing device. Unlike Embodiment 1, in this embodiment, the cylindrical printing platform 1 is a polygonal prism printing platform, preferably a regular polygonal prism with 6 or more sides; specifically, in this embodiment, it is a regular 12-sided prism printing platform. The printing surface is the side surface of the polygonal prism printing platform 1, i.e., the prism face 6. Printing the 3D model 18 using the polygonal prism printing platform is similar to that of the cylindrical printing platform, except that the spray volume of the printing nozzle 2 on the initial support 17 needs to be controlled to spray more support material at the corresponding positions to make it approximately equal to that of the cylindrical printing platform. Figure 9 (shown in dashed lines), the subsequent printing steps can be the same as those for a cylindrical printing platform.

[0062] As an alternative implementation, the cylindrical printing platform may also be other types of cylindrical printing platforms such as elliptical cylindrical printing platforms, and is not limited to the examples given in Embodiments 1 and 2.

[0063] As one implementation method, as the number of printing layers increases, the angular velocity of the cylindrical printing platform remains constant, while the linear velocity at the location of the printing surface gradually increases, and the printing control program system gradually increases the ejection frequency of the nozzle.

[0064] As another implementation, as the number of printing layers increases, the angular velocity of the cylindrical printing platform is gradually reduced to ensure that the linear velocity of the printing surface remains constant, and the printing control program system controls the nozzle's ejection frequency to remain constant.

[0065] As another implementation, the molding auxiliary device can also be a UV curing module. If the print head sprays sufficiently flat ink, the planarization device can be omitted. When the ink is a liquid photosensitive resin, the print head sprays the ink and then the UV curing module cures and shapes it.

[0066] As another implementation, the molding auxiliary device includes a planarization device and a UV curing module. The UV curing module is located behind the planarization device. When the ink is a liquid photosensitive resin, the ink ejected by the print head is leveled by the planarization device and then cured by the UV curing module.

[0067] It is understood that molding auxiliary devices may also include other devices with auxiliary molding functions, which will not be listed here.

[0068] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A cylindrical 3D printing device, characterized in that: The device includes a cylindrical printing platform, a print head, and a moving structure. The cylindrical printing platform is rotatable around a cylindrical axis. The print head is positioned opposite to the side of the cylindrical printing platform and is used to spray printing material onto the side, which serves as the printing surface. The moving structure allows the side to move a set distance relative to the print head.

2. The cylindrical 3D printing equipment as described in claim 1, characterized in that: It also includes a forming aid device, which is located behind the print head and is used to assist in forming the printing material. The forming aid device is arranged opposite to the side, and the side can move relative to the print head and the forming aid device by a set distance through the moving structure.

3. The cylindrical 3D printing equipment as described in claim 2, characterized in that: Defined by the radial projection of the cylindrical 3D printing equipment onto the cylindrical printing platform, with the axis of the cylindrical printing platform as point A, the ejection center point of the printing nozzle as point B, and the forming assistance center point of the forming auxiliary device as point C, the moving structure drives the cylindrical printing platform to move away from the printing nozzle along the angle bisector of ∠BAC; or, the moving structure drives the forming auxiliary device to move away from the cylindrical printing platform along the extension of AC, and the moving structure drives the printing nozzle to move away from the cylindrical printing platform along the extension of AB.

4. The cylindrical 3D printing equipment as described in claim 1, characterized in that: It also includes a printhead mounting base, which is equipped with a printhead movement mechanism. While the cylindrical printing platform rotates around the axis of the column, the printhead movement mechanism drives the printhead to move linearly along a line parallel to the axis of the column. After the printhead moves from the first end to the second end of the cylindrical printing platform, the cylindrical printing platform moves away from the printhead by a printing layer thickness through the moving structure.

5. The cylindrical 3D printing equipment according to claim 3, characterized in that: The moving structure is a printing platform moving mechanism, including a lead screw motor, a slide rail, and a slider. The lead screw motor is connected to the slide rail for transmission, and the slider slides in cooperation with the slide rail. The slider is connected to a fixed seat, and the fixed seat is connected to the cylindrical printing platform. The lead screw motor drives the cylindrical printing platform to move along the slide rail, and the slide rail is parallel to the angle bisector of ∠BAC.

6. The cylindrical 3D printing equipment according to claim 2, characterized in that: The printhead mounting base is connected to the forming auxiliary device, which includes a planarization device and / or a UV curing device. The planarization device is located behind the printhead and is used to level the printing material. The UV curing device is located behind the printhead and is used to UV cure the printing material. The planarization device includes a leveling roller and a leveling motor that drives the leveling roller to rotate. The leveling roller spans the entire side surface, and the length of the leveling roller is greater than the effective printing length of the cylindrical printing platform. The cylindrical printing platform and the leveling roller always maintain their original rotation direction.

7. The cylindrical 3D printing equipment according to claim 6, characterized in that: The cylindrical printing platform includes a cylindrical printing platform, a polygonal prism printing platform, or an elliptical cylindrical printing platform.

8. A 3D printing method using a cylindrical 3D printing apparatus as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Generate a series of concentric cylindrical sheet files: Import the data model file to be printed into the software, create concentric cylindrical cutting surfaces, cut the concentric cylindrical cutting surfaces and data model files into a series of concentric cylindrical sheet files and transfer them to the cylindrical 3D printing equipment. (2) Print 3D models according to a series of concentric cylindrical sheet files: While the cylindrical printing platform rotates, the printing nozzle moves in a straight line along the parallel line of the axis of the cylindrical printing platform and sprays printing. The forming auxiliary device assists in forming. Whenever the printing nozzle moves from the first end to the second end of the cylindrical printing platform, the moving structure drives the cylindrical printing platform away from the printing nozzle by a distance of one printing layer thickness along the angle bisector of ∠BAC. The printing nozzle moves in a straight line in the opposite direction to print until printing is completed.

9. A 3D printing method using a cylindrical 3D printing device according to claim 8, characterized in that: In step (1), the specific method for importing the data model file to be printed into the software is as follows: send the data model file to be printed to the model data layout software, place the model file to be printed on the column printing platform virtually presented by the computer software, and according to the user's requirements for placement direction and position, generate support along the radial direction of the column printing platform and the projection direction towards the axis of the column printing platform for the model placed on the column printing platform, and generate the corresponding support to form the model layout file.

10. A 3D printing method using a cylindrical 3D printing device according to claim 8, characterized in that: In step (1), the specific method for establishing the concentric cylindrical cutting surface is as follows: the radius of the concentric cylindrical cutting surface gradually increases according to the layer thickness r, that is, the radius of the next concentric cylindrical cutting surface is larger than the previous concentric cylindrical cutting surface by a printing layer thickness r, and the axial length of the concentric cylindrical cutting surface is equal to the effective printing length of the cylindrical printing platform.

11. A 3D printing method using a cylindrical 3D printing device according to claim 8, characterized in that: In step (2), as the number of printing layers increases, the angular velocity of the cylindrical printing platform remains constant, while the linear velocity at the location of the printing surface gradually increases, thereby gradually increasing the ejection frequency of the nozzle; or, as the number of printing layers increases, the angular velocity of the cylindrical printing platform gradually decreases to ensure that the linear velocity at the location of the printing surface remains constant, thereby maintaining the ejection frequency of the nozzle.

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