A 3D printer and printing method based on the surface tension of liquid

Abstract

The present invention belongs to the technical field of 3D printing, and particularly relates to a 3D printer and a printing method based on liquid surface tension. It includes a light source for providing curing light, a titration device for providing printing material, a thin film forming structure of the printing material, and a printing platform; wherein, the thin film forming structure is provided with a through hole, the through hole is located in the focal plane of the curing light and is parallel to the surface of the printing platform; the titration device is arranged above the thin film forming structure, titrates the printing material onto the surface of the thin film forming structure, and the thin film forming structure receives the printing material from the titration device and forms a liquid film at the through hole. The present invention cures by directly irradiating the thin film formed by the printing material with curing light, greatly shortening the printing time, improving the printing efficiency, reducing the overall energy consumption, eliminating the problem of defocus, and ensuring higher printing accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing, and particularly relates to a 3D printer and a printing method based on liquid surface tension. Background Art

[0002] Stereolithography is a traditional and relatively mature 3D printing technology. This technology uses ultraviolet light or other forms of light sources to cure photosensitive resins, and constructs three-dimensional objects by curing layer by layer. Due to its high resolution and fine printing quality, this technology is widely used in many fields such as medicine, engineering, and art. However, in the traditional stereolithography 3D printing technology, the printing process depends on the light source passing through the oxygen-permeable film or light-transmitting film at the bottom of the printing material pool. This design causes the intensity of light to be attenuated during transmission, and thus a higher-power projection light machine is required for 3D printing. In addition, due to the blocking of light by the film, the uniformity of light is affected, resulting in a certain defocus phenomenon, which has an adverse effect on the printing accuracy. Summary of the Invention

[0003] Aiming at the problems of light intensity attenuation and defocus caused by the above 3D printer passing through the head oxygen-permeable film or light-transmitting film, the purpose of the present invention is to provide a 3D printing device and a printing method. The 3D printing device forms a film by relying on the surface tension of the liquid through the way of dripping the printing material, and can realize efficient photocuring printing while solving the defocus problem.

[0004] To achieve the above invention purpose, the first technical solution provided by the present invention discloses a 3D printing device, including a light source for providing curing light, a titration device for providing printing material, a film forming structure for the printing material, and a liftable printing platform; wherein, the titration device is arranged above the film forming structure, drips the printing material on the surface of the film forming structure, a through hole is provided on the film forming structure, so that the printing material forms a liquid film at the through hole, and the printing platform is movably arranged corresponding to the through hole, so that the liquid film formed at the through hole is located in the focal plane of the curing light and is parallel to the surface of the printing platform.

[0005] Further, the radial cross-sectional area of the through hole is 5 - 25 mm 2 .

[0006] Further, the film forming structure is a ring body.

[0007] Further, the film forming structure is a circular ring.

[0008] Further, the printing platform is arranged above the film forming structure, and the light source is arranged below the film forming structure.

[0009] Further, the light source further includes a reflector, and the curing light reflected by the reflector passes through the through-hole focal plane.

[0010] Further, there is at least one titration device, and it is detachable.

[0011] The second technical solution of this application discloses a 3D printing method for the above 3D printing device, including:

[0012] The titration device extrudes the printing material onto the surface of the film-forming structure to form a uniform liquid film at the through-hole.

[0013] The curing light provided by the light source is used to cure-print the liquid film, and at the same time, the printing platform moves vertically layer by layer relative to the film-forming structure to achieve layer-by-layer stacking of materials.

[0014] Further, during the curing printing process, the titration device ensures that the film does not break by controlling the dropping frequency and the dropping amount.

[0015] Further, when it is necessary to replace the printing material, the liquid film is broken by shaking or knocking the film-forming structure, and then it is cleaned. After that, the titration device is replaced to achieve the replacement of the printing material.

[0016] The present invention has the following beneficial effects:

[0017] 1. In the present invention, the curing light directly irradiates the film formed by the printing material for curing, which greatly shortens the printing time and improves the printing efficiency; at the same time, it avoids the problem of light intensity attenuation that occurs when the light source in the prior art passes through the oxygen-permeable film or the light-transmitting film, so that the curing process can be completed with a lower light intensity, reducing the overall energy consumption; in addition, since the light does not pass through the light-transmitting or oxygen-permeable film, the influence of the microscopic structure of the film on the light is avoided, eliminating the problem of defocus, and ensuring higher printing accuracy.

[0018] 2. As Figure 3 shown, in the prior art, since the printing material is placed in the printing material pool, the printing platform can only be placed above the printing material pool. At the same time, in order to avoid physical interference between the printing platform and the printing material pool, it can often only move up and down, restricting the degree of freedom; while in this application, since there is no printing material pool, the printing material forms a film through the through-hole in the film-forming structure and is directly cured by the light source. Therefore, the position of the printing platform is not restricted and can be located above or below the film-forming structure. The support structure of the printing platform can also be replaced with a robotic arm to freely adjust the horizontal, vertical and even rotational movement of the printing platform. When printing some special structures, traditional light-curing printing methods must add supports. However, in this application, since the printing degree of freedom is not restricted, when printing these special structures, supports can be not added, but the relative position between the printing material and the printing platform can be adjusted by the robotic arm.

[0019] 3. When replacing the printing material, the prior art requires disposing of the printing material in the original printing material pool, cleaning and drying the printing material pool before filling it with new printing material. At the same time, the printing material pool and the oxygen-permeable or light-transmitting film are easily damaged during the operation process. The replacement process is complex and time-consuming. However, in this application, since multiple titration devices can exist simultaneously, different printing materials can be stored simultaneously, and the titration device is detachable. Therefore, only by oscillating or knocking can the liquid film on the structure of the film be broken, and after dropping the new material to form a film, the replacement of the printing material can be achieved, greatly saving the time consumed by switching the printing material pool.

[0020] 4. In the prior art, the printing material of a light-curing 3D printing device is generally stored in a printing pool. Therefore, only a small part of the printing material can be utilized, and the rest will be wasted. In this application, since there is no printing pool, the only material that may be wasted after printing is the material film formed on the structure of the film, and there is no material adhering to the periphery of the printing pool. Therefore, the utilization rate of the printing material can be improved.

[0021] 5. During the traditional light-curing 3D printing process, as printing progresses, the liquid level of the material will continuously drop, reducing the printing accuracy. However, in this application, there will be no problem of liquid level drop. Description of the Drawings

[0022] Figure 1 、 Figure 2 is a schematic perspective view of the 3D printing device provided by the present invention.

[0023] Reference numerals in the figure:

[0024] 1. Light source;

[0025] 2. Support structure;

[0026] 3. Printing platform support structure;

[0027] 4. Motor;

[0028] 5. Titration device;

[0029] 6. Lead screw and its housing;

[0030] 7. Reflector;

[0031] 8. Light ray;

[0032] 9. Film forming structure;

[0033] 10. Printing material;

[0034] 11. Printing platform;

[0035] 12. Printed product;

[0036] Appendix Figure 3 It is a part with limited degrees of freedom in the prior art 3D printing. Specific Embodiments

[0037] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0038] Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that for the sake of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and devices should be regarded as part of the authorization specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary, rather than as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0039] In addition, in the present application, spatial relative terms such as "beneath", "below", "under", "down", "above", "on", "over", "higher", "side" (for example, in "side wall"), etc., are used to describe the relationship between one element and another (other) element as shown in the drawings. The spatial relative terms are intended to include different orientations of the device in use, operation, and / or manufacture in addition to the orientation depicted in the drawings. For example, if the device in the drawing is flipped, an element described as "beneath" or "under" other elements or features will subsequently be defined as "above" the other elements or features. Thus, the exemplary term "beneath" can include both above and below orientations. In addition, the device can be positioned otherwise (for example, rotated 90 degrees or at other orientations), and accordingly, the spatial relative descriptive terms used herein are interpreted.

[0040] Figures 1-2 The 3D printing device provided by the present invention is shown. The 3D printing device includes a light source 1 for providing curing light 8, a titration device 5 for providing printing materials, a thin film forming structure 9 for printing materials, and a printing platform 10.

[0041] As shown Figure 2 in FIG. 94, the film forming structure 9 is a closed-loop structure provided with a through hole, which can be made into various closed-loop shapes, such as a perfect circle, an ellipse, a square or other irregular shapes. When the titration device titrates the printing material onto the surface of the film forming structure, under the action of gravity and surface tension, the printing material will form a uniform liquid film at the through hole of the closed-loop structure, so that it can be directly cured by a curing light source. As shown Figure 1 in FIG. 95, the film forming structure is fixed and supported by the support structure 2 to provide a stable printing platform.

[0042] It can be understood that in this process, in order to form a liquid film, the size of the through hole of the film forming structure is affected by the properties of the printing material itself (such as surface tension, viscosity, etc.). The size of its radial cross-sectional area is just enough to form a closed-loop liquid film. For example, when the printing material is resin, its radial cross-sectional area is 5-25 mm 2 , and if it is too large, a liquid film cannot be formed. Preferably, when the film forming structure is an arc-shaped closed-loop structure, such as an ellipse or a perfect circle, the formation speed of its liquid film is faster and more uniform. Most preferably, it is a perfect circle. When it is a perfect circle, the diameter of its through hole is 3-5 mm.

[0043] As shown Figure 1 in FIG. 100, the printing platform 10 is movably arranged corresponding to the through hole, so that the liquid film formed at the through hole is located in the focal plane of the curing light 8 and is parallel to the surface of the printing platform 10, so that the curing light can efficiently cure the film in the film forming structure. It can be understood that in this process, the light source can be used to control the light intensity and fine-tune the angle through a program, so as to adjust the curing optical fiber to pass through the focal plane of the liquid film. This belongs to the conventional method in the field and is not limited in this application. Only preferred embodiments are provided. For example Figure 1 as shown in the side of the film forming structure in FIG. 101, and then the path of the curing light is changed by the reflector 7, so that the film forming structure is located in the focal plane of the curing light.

[0044] As shown Figure 2 in FIG. 104, the titration device 5 is arranged above the film forming structure 9 and is fixed by a support structure (not shown in the figure). The rate and amount of the printing material titrated by the titration device can be dynamically controlled according to the actual state of the film, so as to avoid the film from breaking due to insufficient liquid volume. For example, when the surface tension of the printing material is insufficient, the dripping frequency can be increased to maintain the integrity of the film. The thickness of the liquid film can also be controlled by adjusting the dripping speed of the drip head to meet different printing requirements. The titration process can be directly driven by a motor or driven by an air compressor by adjusting the air pressure. This application is not particularly limited.

[0045] In a preferred embodiment, there may be multiple titration devices 5, which are equipped with different printing materials and are detachable, so that rapid replacement of the printing materials can be achieved. During the actual replacement process, it is only necessary to break the liquid film on the film forming structure, then clean and dry the film forming structure, and then the other printing material can be continuously dropped. On the other hand, since the film forming structure is relatively simple and detachable, the film forming structure can also be directly removed and replaced with a film forming structure without added material, and then cleaned uniformly after printing is completed.

[0046] As Figure 1 shown, the printing platform 11 is supported by a lead screw and its housing 6, and is driven to move by a motor 4. The printing platform is parallel to the film forming structure; As Figure 2 shown, when one layer of printing is completed, the motor 4 drives the movement of the printing platform, so that the finished product of this layer contacts the liquid film for the next layer of printing, and this step is continuously repeated, so as to realize the continuous stacking of materials and obtain the printed product.

[0047] In a preferred embodiment, the support structure of the printing platform, the lead screw and its housing 6 can be replaced by a robotic arm, and the movement of the printing platform can be freely adjusted by the robotic arm, such as moving up, down, left, right, tilting to one side, rotating, flipping, etc. An embodiment of the present application discloses a printing method of the above 3D printing structure, specifically: the titration device extrudes the printing material onto the surface of the film forming structure to form a uniform liquid film at the through holes; The curing light is provided by the light source to cure and print the liquid film. At the same time, the printing platform moves layer by layer on the film forming structure to realize the layer-by-layer stacking of materials, so as to obtain the printed product.

[0048] It can be understood that in this process, first, the film forming structure 9 needs to be fixed on the support structure 2 to ensure its stability, and then it is adjusted to be located in the focal plane of the curing light 8; Then connect the printing platform to its support structure, and then adjust it to be parallel to the film forming structure 9. At the same time, add the printing materials required for printing to the titration device. The titration device ensures that the film does not break by controlling the dropping frequency and dropping amount during the curing printing process. When it is necessary to replace the printing material, the liquid film is broken by shaking or knocking the film forming structure, and then cleaned, and then the titration device is replaced to realize the replacement of the printing material.

[0049] In the above printing method, the titration material needs to continuously and uniformly drop the printing material to form a uniform liquid film.

[0050] During printing, it is necessary to slowly move the support structure of the printing platform to make the printing platform descend together with it until the surface of the printing platform contacts the liquid film.

[0051] The above has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements. The scope of protection required by the present invention is defined by the appended claims, the specification and their equivalents.

Claims

1. A 3D printing device, characterized in that: The invention comprises a light source for providing curing light, a titration device for providing printing material, a film forming structure for the printing material and a printing platform; wherein the titration device is arranged above the film forming structure to titrate the printing material onto the surface of the film forming structure; a through hole is arranged on the film forming structure so that the printing material forms a liquid film at the through hole; the printing platform is movably arranged corresponding to the through hole so that the liquid film formed at the through hole is located in the focal plane of the curing light and is parallel to the surface of the printing platform.

2. The 3D printing device according to claim 1, characterized in that: The radial cross-sectional area of ​​the through hole is 5 to 25 mm 2 .

3. The 3D printing device according to claim 1 or 2, characterized in that: The film forming structure is a ring.

4. The 3D printing device according to claim 3, characterized in that: The film-forming structure is a ring.

5. The 3D printing device according to claim 1, characterized in that: The printing platform is supported by a mechanical arm, and the mechanical arm can freely regulate the movement of the printing platform.

6. The 3D printing device according to claim 1, characterized in that: The light source further comprises a reflector, and the curing light reflected by the reflector passes through the through-hole focal plane.

7. The 3D printing device according to claim 1, characterized in that: The titration device is ≥1 and is detachable.

8. The 3D printing method according to any one of claims 1 to 7, characterized in that: include: The titration device extrude the printing material onto the surface of the film forming structure, so that it forms a uniform liquid film at the through hole; The light source provides curing light to cure and print the liquid film, and the printing platform moves layer by layer perpendicular to the film to form a structure to achieve layer-by-layer stacking of materials.

9. The 3D printing method according to claim 8, characterized in that: The titration device ensures that the film is not broken by controlling the dropping frequency and the dropping amount during the curing printing process.

10. The 3D printing method according to claim 8, characterized in that: When the printing material needs to be replaced, the liquid film is broken by shaking or knocking the film-forming structure, and then cleaned, and then the titration device is replaced to achieve the replacement of the printing material.

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