A pull-up DLP additive manufacturing apparatus and method of manufacturing

Abstract

The application discloses a kind of pull-up DLP additive manufacturing equipment and manufacturing method, pull-up DLP additive manufacturing equipment includes: printing tank and printing window, printing window is as the tank bottom of printing tank and is fixed with the printing tank, printing platform is set in the upper of printing tank, light source system is set in the lower of printing window;At least one ultrasonic transducer is installed on the outer wall of printing tank, each ultrasonic transducer is connected with ultrasonic generator;Flow channel for passing through transparent cooling medium is opened in printing window.The printing platform of pull-up DLP additive manufacturing equipment is lifted 1 layer thickness when printing, the printing platform is lifted 1 layer thickness height after each layer solidification layer printing is completed, and ultrasonic generator is opened in lifting process, and ultrasonic generator is closed after lifting is completed.The application effectively reduces the release force between solidification layer and printing window, can completely cancel the process of additional lifting and descending again, effectively improves processing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of DLP additive manufacturing technology, specifically relating to an up-pull DLP additive manufacturing equipment and manufacturing method. Background Technology

[0002] DLP (Digital Light Processing) additive manufacturing technology belongs to the photopolymerization and curing category. Its core principle is to use a digital light projector to project sliced ​​models layer by layer onto the surface of liquid photosensitive resin. Ultraviolet light then cures the resin layers, which are then stacked to form a three-dimensional solid. Based on the direction of the printing platform's movement, DLP additive manufacturing processes are divided into sinking and pulling types. Sinking DLP additive manufacturing technology offers advantages such as high printing accuracy and good model quality, but it has higher equipment costs and is suitable for printing larger models. Pulling DLP additive manufacturing technology offers faster printing speeds, smaller equipment size, saves printing materials, has a relatively simpler structure, and lower costs, making it more suitable for smaller models.

[0003] The pull-out DLP additive manufacturing technology currently faces two technical challenges: First, the release force between the cured layer formed by the photosensitive resin and the printing window is too large, leading to separation difficulties. This can cause model deformation, structural defects, and fracture deformation, resulting in printing failure. Second, the poor fluidity of liquid photosensitive resin makes it difficult to quickly fill the printing area and level out as the printing platform rises, potentially causing interlayer defects (such as voids, uneven thickness, and fractures). To allow sufficient time for resin flow, ensure adequate resin filling, and reduce damage to the parts from the release force, the printing platform needs to rise 100 times the layer thickness (i.e., the "peel-off height") after each cured layer is printed, and then descend to the printing height. This significantly extends the printing time for each layer, resulting in low production efficiency.

[0004] Regarding the first problem, current mature solutions generally fall into three categories: placing a release film (FEP film) above the printing window, synthesizing hydrogel in situ above the printing window, or introducing an oxygen-permeable window (such as a Teflon film) at the bottom of the resin tank. While these three methods can reduce the release force between the cured layer and the printing window to some extent, increasing the speed of the printing platform and thus improving printing efficiency, each has its drawbacks: the release film is not ideal for reducing release force; the bond between the hydrogel and the printing window is irreversible, making it difficult to remove the hydrogel, and when the hydrogel needs to be replaced, the entire printing tank generally needs to be replaced; and the oxygen-permeable window is expensive. Furthermore, these three solutions do not significantly improve resin leveling. Currently, the solution to the problem of slow resin leveling leading to part defects is still to raise the printing platform to the "peel height" after each layer is cured, and then lower it to the predetermined cured layer depth to allow sufficient time for the liquid photosensitive resin to level. However, this solution leads to a longer printing time per layer, reducing overall efficiency. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an up-pull DLP additive manufacturing equipment that is low in cost, easy to control, and can effectively improve processing efficiency while ensuring the quality of printed samples.

[0006] Another objective of this invention is to provide an up-pull DLP additive manufacturing method using the above-mentioned up-pull DLP additive manufacturing equipment. This up-pull DLP additive manufacturing method can effectively reduce the release force between the cured layer and the printing window, and improve the fluidity and leveling speed of the resin liquid (liquid photosensitive resin).

[0007] Another object of the present invention is to provide the use of the above-described pull-up DLP additive manufacturing equipment in improving the processing efficiency of photosensitive resins.

[0008] The objective of this invention is achieved through the following technical solutions.

[0009] A pull-up DLP additive manufacturing equipment includes: a printing tank, a printing window, a printing platform, and a light source system. The printing window serves as the bottom of the printing tank and is fixed to the printing tank. The printing tank is used to contain liquid photosensitive resin. The printing platform is located directly above the printing tank, and the light source system is located directly below the printing window.

[0010] At least one ultrasonic transducer is installed on the outer wall of the printing tank, and each ultrasonic transducer is connected to an ultrasonic generator.

[0011] The printing window has channels for the passage of a transparent cooling medium.

[0012] In the above technical solution, one end of the flow channel is connected to the cooling pipe, and the cooling pipe is connected to the transparent cooling medium source. A first flow control valve and a fluid pump are installed on the cooling pipe.

[0013] In the above technical solution, the pull-up DLP additive manufacturing equipment also includes: at least one first infrared temperature sensor, which is used to monitor the bottom temperature of the printing window in real time;

[0014] In the above technical solution, the flow channel is a serpentine flow channel or a layered cavity.

[0015] In the above technical solution, when the flow channel is a serpentine flow channel, the serpentine flow channel includes multiple transverse flow channels and multiple longitudinal flow channels. The multiple transverse flow channels are all arranged laterally and are parallel to each other, and the multiple longitudinal flow channels are all arranged longitudinally and are parallel to each other. Any two adjacent transverse flow channels are connected end to end through a longitudinal flow channel.

[0016] In the above technical solution, when the flow channel is a layered cavity, a flow divider is installed at one end of the layered cavity, and a flow combiner is installed at the other end of the layered cavity, wherein:

[0017] The end of the distributor away from the layered cavity is used to connect to the cooling pipe. A first perforated plate is provided at the connection between the layered cavity and the distributor, and a second perforated plate is provided at the connection between the distributor and the cooling pipe. Both the first and second perforated plates are perpendicular to the bottom plane of the layered cavity.

[0018] In the above technical solution, at least one second infrared temperature sensor is provided above the printing tank. The second infrared temperature sensor is used to monitor the real-time temperature of the photosensitive resin above the printing tank.

[0019] The outer wall of the printing tank is also equipped with a heat preservation device, which is equipped with an inlet pipe and an outlet pipe. The inlet pipe is used to introduce hot water, and a water pump and a second flow control valve are installed on the inlet pipe to control the inlet flow rate. The outlet pipe is used to discharge the hot water in the heat preservation device.

[0020] In the above technical solution, the insulation device is an insulation jacket or an insulation pipe.

[0021] In the above technical solution, when the heat preservation device is a heat preservation jacket, a number of clearance holes are provided on the outer wall of the heat preservation jacket, and the ultrasonic transducer is fixed in each clearance hole.

[0022] In the above technical solution, when the heat preservation device is a heat preservation pipe, the heat preservation pipe is spirally wound around the outside of the printing tank, one end of the heat preservation pipe serves as the water inlet pipe, and the other end serves as the water outlet pipe.

[0023] The above-mentioned pull-type DLP additive manufacturing equipment and its pull-type DLP additive manufacturing method include:

[0024] The temperature at the bottom of the printing window obtained by the first infrared temperature sensor is less than or equal to a preset first temperature, and the real-time temperature of the photosensitive resin above the printing tank obtained by the second infrared temperature sensor is greater than or equal to a preset second temperature. The pull-up DLP additive manufacturing equipment performs 3D printing.

[0025] The initial vertical distance between the printing platform and the printing window is 0mm. The printing platform is raised by 1 layer thickness. The light source system is turned on, and the light source system irradiates the photosensitive resin in the printing tank to print layer by layer.

[0026] After each cured layer is printed, the printing platform is raised by one layer thickness. During the upward raising of the printing platform, the ultrasonic generator is turned on to make the ultrasonic transducer vibrate. After the printing platform is raised, the ultrasonic generator is turned off.

[0027] The above-mentioned up-pulling DLP additive manufacturing equipment is used to improve the processing efficiency of photosensitive resin.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention opens a flow channel inside the printing window. During operation, a transparent cooling medium is controlled to flow into the flow channel, thereby reducing the temperature of the printing window. Through heat conduction, the temperature of the liquid photosensitive resin in contact with the printing window is maintained at a relatively low temperature, thereby effectively reducing the release force between the cured layer and the printing window.

[0030] 2. In this invention, an ultrasonic transducer is installed on the outer wall of the printing tank. It is activated when the printing platform rises after curing. The ultrasonic transducer generates vibration and transmits the vibration to the liquid photosensitive resin in the printing tank. This can improve the flow performance of the liquid photosensitive resin, help it to level quickly, and thus further increase the speed at which the printing platform rises and accelerate the printing efficiency.

[0031] 3. The present invention provides a heat insulation jacket or heat insulation pipe on the outer wall of the printing tank, and introduces water with a certain temperature into the heat insulation jacket or heat insulation pipe to appropriately increase the temperature of the liquid photosensitive resin in the upper part, while further improving the fluidity of the liquid photosensitive resin, thereby improving curing efficiency and printing efficiency.

[0032] 4. The pull-up DLP additive manufacturing equipment of the present invention can significantly shorten the height of the printing platform after each layer exposure while ensuring the quality of the finished product. It can even completely eliminate the additional process of raising the platform to the peeling height and then lowering it. Moreover, the pull-up DLP additive manufacturing method of the present invention can save 49.59% to 79.82% of the time compared with the traditional printing method, and effectively improve the processing efficiency while ensuring the quality of the printed samples.

[0033] 5. The pull-up DLP additive manufacturing equipment of the present invention can discard the release film. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the structure of the pull-up DLP additive manufacturing equipment in Example 1;

[0035] Figure 2 This is a cross-sectional schematic diagram of the pull-up DLP additive manufacturing equipment in Example 1;

[0036] Figure 3 This is a schematic diagram of the serpentine flow channel in Example 3;

[0037] Figure 4 This is a schematic diagram of the layered cavity structure in Example 4;

[0038] Figure 5 This is a cross-sectional schematic diagram of the pull-up DLP additive manufacturing equipment in Example 6;

[0039] Figure 6 This is a schematic diagram of the structure of the pull-up DLP additive manufacturing equipment in Example 6;

[0040] Figure 7 This is a cross-sectional schematic diagram of the pull-up DLP additive manufacturing equipment in Example 7;

[0041] Figure 8 This is a cross-sectional schematic diagram of the pull-up DLP additive manufacturing equipment for Comparative Example 1;

[0042] Figure 9 (a) is a photograph of a sample manufactured using the pull-up DLP additive manufacturing method of Example 8, and (b) is... Figure 9 (a) is a side view of the sample, (c) is a photograph of the sample manufactured using the up-pulling DLP additive manufacturing method of Comparative Example 2, and (d) is... Figure 9 Side view of sample (c);

[0043] Figure 10 This is a schematic diagram showing the connection between the sample and the printing platform in Comparative Example 2;

[0044] Figure 11 (a) is a top view of a sample manufactured using the up-pulling DLP additive manufacturing method of Comparative Example 3, and (b) is a top view of a sample manufactured using the up-pulling DLP additive manufacturing method of Comparative Example 4.

[0045] Figure 12 (a) is a photograph of the internal structure of the sample in Example 8, and (b) is a photograph of the internal structure of the sample in Comparative Example 2.

[0046] Among them, 1: printing slot, 2: printing window, 3: printing platform, 4: light source system, 5: serpentine flow channel, 6: insulation jacket, 7: ultrasonic transducer, 8: first infrared temperature sensor, 9: second infrared temperature sensor, 10: first flow control valve, 11: second flow control valve, 12: insulation pipe, 13: flow divider, 14: first perforated plate, 15: second perforated plate, 16: guide plate, 17: confluencer, 18: layered cavity. Detailed Implementation

[0047] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0048] Example 1

[0049] like Figure 1 as well as Figure 2As shown, an up-pull DLP additive manufacturing equipment includes: a printing tank 1, a printing window 2 (the material of the printing window 2 is fluorinated ethylene propylene copolymer), a printing platform 3, and a light source system 4. The printing window 2 serves as the bottom of the printing tank 1 and is fixed to the printing tank 1. The printing tank 1 is used to contain liquid photosensitive resin (photosensitive resin brand: FUNCRECOL, model: textured matte resin). The printing platform 3 is located directly above the printing tank 1 and can move in a direction perpendicular to the printing window 2. The light source system 4 is located directly below the printing window 2. The distance between the light source system 4 and the printing window 2 needs to be set according to the application scenario. If the application scenario is desktop, the distance between the light source system 4 and the printing window 2 ranges from 50mm to 150mm; if the application scenario is industrial, the distance between the light source system 4 and the printing window 2 ranges from 200mm to 400mm.

[0050] At least one ultrasonic transducer 7 is installed on the outer wall of the printing tank 1. Each ultrasonic transducer 7 is connected to an ultrasonic generator. The frequency of the ultrasonic transducer 7 is 20-40kHz and the amplitude is 5-10μm.

[0051] The printing window 2 has a flow channel for the passage of a transparent cooling medium, the temperature of which is 5 to 20°C.

[0052] The working process of the above-mentioned pull-up DLP additive manufacturing equipment is as follows: A transparent cooling medium is introduced into the flow channel to reduce the temperature of the printing window 2. Through heat conduction, the liquid photosensitive resin at the bottom of the printing tank 1 is maintained at a relatively low temperature. The light source system 4 is turned on, and the light source system 4 projects light of a specific wavelength onto the liquid photosensitive resin located above the printing window 2. After illumination, the bottom of the liquid photosensitive resin is cured to form a cured layer. The transparent cooling medium inside the printing window 2 can effectively reduce the release force between the cured layer and the printing window 2. Then, the printing platform 3 is raised. When the printing platform 3 is raised, the ultrasonic generator is turned on to make the ultrasonic transducer 7 vibrate. The ultrasonic transducer 7 transmits the vibration to the photosensitive resin in the printing tank 1, improving the flow performance of the photosensitive resin and helping to level it quickly, thereby further increasing the rising speed of the printing platform 3 and accelerating the printing efficiency.

[0053] The pull-up DLP additive manufacturing equipment in Example 1 does not contain a release film.

[0054] Example 2

[0055] A pull-up DLP additive manufacturing equipment, based on Example 1, introduces a transparent cooling medium into a flow channel through a cooling pipe located outside the printing window 2. One end of the flow channel is connected to the cooling pipe, which is connected to a transparent cooling medium source (transparent cooling medium source: structure that supplies transparent cooling medium). A first flow control valve 10 and a fluid pump are installed on the cooling pipe. The adjustable flow rate range of the fluid pump is 0.3 to 0.5 L / min, and the output pressure of the fluid pump is 0.5 to 1 MPa (the output pressure is the pressure value generated by the transparent cooling medium at the outlet of the fluid pump). The transparent cooling medium is water.

[0056] The pull-up DLP additive manufacturing equipment also includes: at least one first infrared temperature sensor 8, which is used to monitor the bottom temperature of the printing window 2 in real time. The installation position of the first infrared temperature sensor 8 is not limited, as long as it does not affect the light source system 4 from projecting light onto the liquid photosensitive resin above the printing window 2.

[0057] Example 3

[0058] An up-pull DLP additive manufacturing equipment, based on Example 2, such as... Figure 3 As shown, the flow channel is a serpentine flow channel 5, which includes multiple transverse flow channels and multiple longitudinal flow channels. The multiple transverse flow channels are arranged laterally and are parallel to each other, and the multiple longitudinal flow channels are arranged longitudinally and are parallel to each other. Any two adjacent transverse flow channels are connected end to end through a longitudinal flow channel. The serpentine flow channel 5 can make the transparent cooling medium distributed relatively evenly in the printing window 2, thereby making the temperature of the printing window 2 uniform. The spacing between adjacent transverse flow channels in the serpentine flow channel 5 is 3-5mm, the width of the flow channel (transverse flow channel and longitudinal flow channel) is 1-2mm, and the upper shape of the flow channel cross-section is arched.

[0059] Example 4

[0060] like Figure 4 As shown, an up-pull DLP additive manufacturing apparatus, based on Example 2, has a flow channel of layered cavity 18. A splitter 13 is installed at one end of the layered cavity 18, and a combiner 17 is installed at the other end of the layered cavity 18. Wherein:

[0061] The end of the distributor 13 away from the layered cavity 18 is used to connect to the cooling pipe. A first perforated plate 14 is provided at the connection between the layered cavity 18 and the distributor 13, and a second perforated plate 15 is provided at the connection between the distributor 13 and the cooling pipe. Both the first perforated plate 14 and the second perforated plate 15 are perpendicular to the bottom plane of the layered cavity 18, and the aperture of both the first perforated plate 14 and the second perforated plate 15 is 2mm.

[0062] The distributor 13 is provided with several guide plates 16, and independent channels are formed between adjacent guide plates 16 to distribute the transparent cooling medium.

[0063] In this embodiment, the flow channel is designed as a layered cavity 18, which can increase the contact area between the transparent cooling medium and the printing window 2. The design of the flow divider 13, the first mesh plate 14, the second mesh plate 15, and the guide plate 16 can make the transparent cooling medium entering from the cooling pipe as evenly distributed as possible in the layered cavity 18.

[0064] Example 5

[0065] An up-pull DLP additive manufacturing apparatus, based on embodiment 3, has at least one second infrared temperature sensor 9 disposed above the printing tank 1, the second infrared temperature sensor 9 being used to monitor the real-time temperature of the photosensitive resin in the printing tank 1.

[0066] The outer wall of the printing tank 1 is also equipped with a heat preservation device, which is equipped with an inlet pipe and an outlet pipe. The inlet pipe is used to introduce hot water (the temperature of the hot water is 35-45℃, which can increase the temperature of the liquid photosensitive resin in the printing tank 1, further improve the fluidity of the liquid photosensitive resin, and improve the curing efficiency). A water pump and a second flow control valve 11 are installed on the inlet pipe to control the inlet water flow rate. The outlet pipe is used to discharge the hot water in the heat preservation device.

[0067] Example 6

[0068] An up-pull DLP additive manufacturing equipment, based on Example 5, such as... Figure 5 , Figure 6 As shown, the heat preservation device is a heat preservation jacket 6, which is filled with hot water. Several clearance holes are provided on the outer wall of the heat preservation jacket 6, and the ultrasonic transducer 7 is fixed in each clearance hole.

[0069] Example 7

[0070] An up-pull DLP additive manufacturing equipment, based on Example 5, such as... Figure 7 As shown, the heat preservation device is a heat preservation pipe 12, which is spirally wound around the outside of the printing tank 1. One end of the heat preservation pipe 12 serves as a water inlet pipe, and the other end serves as a water outlet pipe.

[0071] Example 8

[0072] A pull-up DLP additive manufacturing method includes: performing 3D printing using the pull-up DLP additive manufacturing equipment of Example 6, wherein the bottom temperature of the printing window 2 obtained by the first infrared temperature sensor 8 is less than or equal to a preset first temperature (the preset first temperature is 45°C), and the real-time temperature of the photosensitive resin above the printing tank 1 obtained by the second infrared temperature sensor 9 is greater than or equal to a preset second temperature (the preset second temperature is 35°C), and 3D printing is performed.

[0073] The initial vertical distance between the printing platform 3 and the printing window 2 is 0mm. The printing platform 3 is then raised by one layer thickness (the layer thickness is the thickness of a single cured layer in a single print, taken as 0.05mm). The light source system 4 is then activated, irradiating the photosensitive resin in the printing tank 1 for layer-by-layer printing. In this embodiment, the light source parameters of the light source system 4 are as follows: light source type is UV LED, light source wavelength is 405nm, and UV light power is 2.5W. The exposure area is 533×300. The printing parameters include: printing speed of 50mm / h, printing accuracy of 0.2mm, optical-mechanical resolution of 3840×2160, and pixel size of 0.1388mm.

[0074] After each cured layer is printed, the printing platform 3 is raised by one layer thickness. During the upward raising of the printing platform 3, the ultrasonic generator is turned on to make the ultrasonic transducer 7 vibrate. After the printing platform 3 is raised, the ultrasonic generator is turned off.

[0075] Example 9

[0076] A pull-up DLP additive manufacturing method is basically the same as the pull-up DLP additive manufacturing method in Example 8, except that after each cured layer is printed, the printing platform 3 is first raised by 1 mm and then lowered by 0.95 mm.

[0077] Example 10

[0078] A pull-up DLP additive manufacturing method is basically the same as the pull-up DLP additive manufacturing method in Example 8, except that after each cured layer is printed, the printing platform 3 is first raised by 2mm and then lowered by 1.95mm.

[0079] Comparative Example 1

[0080] Using pull-up DLP additive manufacturing equipment for pull-up DLP additive manufacturing methods, such as Figure 8 As shown, the pull-up DLP additive manufacturing equipment of Comparative Example 1 is basically the same as the pull-up DLP additive manufacturing equipment of Example 1, but the pull-up DLP additive manufacturing equipment of Comparative Example does not contain: the inner channel of the printing window 2 and the ultrasonic transducer 7, and the side of the printing window 2 of the pull-up DLP additive manufacturing equipment of Comparative Example that is in contact with the liquid photosensitive resin is attached with a release film.

[0081] The pull-up DLP additive manufacturing method is basically the same as that in Example 10, except that after each cured layer is printed, the printing platform 3 is raised by 5mm and then lowered by 4.95mm.

[0082] Comparative Example 2

[0083] A pull-up DLP additive manufacturing method is basically the same as the pull-up DLP additive manufacturing method of Comparative Example 1, except that after each cured layer is printed, the printing platform 3 is raised by 1 mm and then lowered by 0.95 mm.

[0084] Comparative Example 3

[0085] A pull-up DLP additive manufacturing method is basically the same as the pull-up DLP additive manufacturing method in Example 8, except that the ultrasonic generator is always kept off (i.e., the ultrasonic generator is also kept off during the process of the printing platform 3 being lifted upward).

[0086] Comparative Example 4

[0087] A pull-up DLP additive manufacturing method is basically the same as the pull-up DLP additive manufacturing method in Example 8, except that: a transparent cooling medium is not introduced into the printing tank 1, and the first infrared temperature sensor 8 and the second infrared temperature sensor 9 do not work.

[0088] When printing large flat workpieces, the pull-up DLP additive manufacturing equipment is prone to problems such as difficulty in detaching the cured layer (excessive release force between the cured layer and the printing window 2), unevenness and flatness of the formed surface due to the large curing area and uneven internal stress distribution. In order to verify the quality performance of the above-mentioned pull-up DLP additive manufacturing method in workpiece printing, the pull-up DLP additive manufacturing methods of Examples 8 to 10 and Comparative Examples 1 to 4 were used to print large flat workpieces of the same size. The size of the large flat workpiece was 100*100*50mm. The exposure time of the light source system 4 was set to 1.2s. The upward lifting speed of the printing platform 3 was 120mm / min and the downward speed was 150mm / min.

[0089] After printing, observe the printed sample. The sample in Example 8 is as follows: Figure 9 (a) and Figure 9 As shown in (b), the sample of Example 8 appears to be intact and has a smooth surface. The samples of Examples 9-10 and Comparative Example 1 are not significantly different from the sample of Example 8.

[0090] from Figure 9 (c) Figure 9 (d) and Figure 10 It can be seen that the sample in Comparative Example 2 performed the worst, with severe deformation at the top and separation between the top of the sample and the printing platform 3. Furthermore, due to the small lifting distance of the printing platform 3 and the lack of an added heat preservation device, the liquid photosensitive resin in the printing tank 1 failed to fill the printing area in time, ultimately resulting in obvious incomplete filling defects and delamination defects in the middle area of ​​the printed part.

[0091] from Figure 11As can be seen in (a), although the sample of Comparative Example 3 is intact, its surface has obvious texture and is not as smooth as the samples in Examples 8-10 and Comparative Example 1. Figure 11 As can be seen in (b), the top of the sample corresponding to Comparative Example 4 shows obvious unevenness and depression;

[0092] Cutting open the samples from Examples 8-10 and Comparative Examples 1-4, it was observed that the internal structures of the four samples prepared in Examples 8-10 and Comparative Example 1 were dense and intact, with no obvious defects. Samples from Example 8 and Comparative Example 2 showed... Figure 12 (a) and Figure 12 As shown in (b), it can be seen that the internal structure of Comparative Example 2 is disordered, severely deformed, and fractured in multiple places, resulting in very poor quality. The internal structures of Comparative Examples 3 and 4 show partial fractures and burrs.

[0093] The time taken to print the entire large planar workpiece in Examples 8-10 and Comparative Examples 1-4 was statistically analyzed, and the percentage of time saved by Examples 8-10 and Comparative Examples 2-4 compared to Comparative Example 1 was calculated, as shown in Table 1 below:

[0094] Table 1

[0095]

[0096] As can be seen from Table 1, Example 8 took the shortest time, saving 79.82% of the time compared to Comparative Example 1.

[0097] The above results show that the pull-up DLP additive manufacturing equipment of the present invention can significantly shorten the height of the printing platform 3 after each layer exposure while ensuring the quality of the finished product. It can even completely eliminate the additional upward lifting and lowering process. Moreover, the pull-up DLP additive manufacturing method using the pull-up DLP additive manufacturing equipment of the present invention can save 49.59% to 79.82% of the time compared with the traditional printing method, effectively improving the processing efficiency while ensuring the quality of the printed samples.

[0098] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. An up-pulling DLP additive manufacturing equipment, characterized in that, include: The printing tank (1), printing window (2), printing platform (3) and light source system (4) are provided. The printing window (2) serves as the bottom of the printing tank (1) and is fixed to the printing tank (1). The printing tank (1) is used to contain liquid photosensitive resin. The printing platform (3) is located directly above the printing tank (1). The light source system (4) is located directly below the printing window (2). At least one ultrasonic transducer (7) is installed on the outer wall of the printing tank (1). The printing window (2) has a flow channel for the passage of a transparent cooling medium; One end of the flow channel is connected to a cooling pipe, and the cooling pipe is connected to a transparent cooling medium source. A first flow control valve (10) and a fluid pump are installed on the cooling pipe. The pull-up DLP additive manufacturing equipment also includes: at least one first infrared temperature sensor (8), which is used to monitor the bottom temperature of the printing window (2) in real time. The flow channel is a serpentine flow channel (5) or a layered cavity (18); When the flow channel is a serpentine flow channel (5), the serpentine flow channel (5) includes multiple transverse flow channels and multiple longitudinal flow channels. The multiple transverse flow channels are all arranged transversely and are parallel to each other, and the multiple longitudinal flow channels are all arranged longitudinally and are parallel to each other. Any two adjacent transverse flow channels are connected end to end through a longitudinal flow channel. When the flow channel is a layered cavity (18), a flow divider (13) is installed at one end of the layered cavity (18), and a flow combiner (17) is installed at the other end of the layered cavity (18), wherein: The end of the distributor (13) away from the layered cavity (18) is used to connect to the cooling pipe. A first perforated plate (14) is provided at the connection between the layered cavity (18) and the distributor (13), and a second perforated plate (15) is provided at the connection between the distributor (13) and the cooling pipe.

2. The up-pulling DLP additive manufacturing equipment according to claim 1, characterized in that, At least one second infrared temperature sensor (9) is provided above the printing tank (1). The second infrared temperature sensor (9) is used to monitor the real-time temperature of the photosensitive resin above the printing tank (1).

3. The up-pulling DLP additive manufacturing equipment according to claim 2, characterized in that, The outer wall of the printing tank (1) is also provided with a heat preservation device, which is equipped with an inlet pipe and an outlet pipe. The inlet pipe is used to introduce hot water, and a water pump and a second flow control valve (11) are installed on the inlet pipe.

4. The up-pulling DLP additive manufacturing equipment according to claim 3, characterized in that, The insulation device is an insulation jacket (6) or an insulation pipe (12).

5. A pull-up DLP additive manufacturing method, characterized in that, When using the pull-up DLP additive manufacturing equipment described in any one of claims 1 to 4 for 3D printing, the initial vertical distance between the printing platform (3) and the printing window (2) is 0 mm, so that the printing platform (3) is raised by 1 layer thickness, the light source system (4) is turned on, and the light source system (4) irradiates the photosensitive resin in the printing tank (1) and prints layer by layer; After each layer of curing is printed, the printing platform (3) is raised by one layer thickness. During the upward raising of the printing platform (3), the ultrasonic generator is turned on to make the ultrasonic transducer (7) vibrate. After the printing platform (3) is raised, the ultrasonic generator is turned off.

6. The up-pulling DLP additive manufacturing method according to claim 5, characterized in that, Make the bottom temperature of the printing window (2) obtained by the first infrared temperature sensor (8) less than or equal to the preset first temperature, and make the real-time temperature of the photosensitive resin above the printing groove (1) obtained by the second infrared temperature sensor (9) greater than or equal to the preset second temperature, and then make the pull-up DLP additive manufacturing equipment perform 3D printing.

7. Use of the up-pulling DLP additive manufacturing equipment as described in any one of claims 1 to 4 in improving the processing efficiency of photosensitive resins.

Images