Exposure control methods, equipment and storage media for photopolymer 3D printing equipment

Abstract

This application provides an exposure control method, device, and storage medium for a photopolymer 3D printing device, relating to the field of 3D printing. The photopolymer 3D printing device includes a printing platform, a material tank, and a light source module. The light source module emits curing light to cure the material to be cured in the material tank and connect it to the printing platform. The method includes: controlling the printing platform to move to a preset printing position and keeping the light source module in an off state; acquiring a first detection value characterizing the flow rate of the material to be cured in the material tank; and controlling the light source module to turn on exposure when the first detection value is within a preset detection value range. In this embodiment, the user does not need to set the off time of the light source module; instead, based on the detection value characterizing the flow rate of the material to be cured in the material tank, the off time is automatically and accurately determined, achieving accurate exposure of the light source module and improving printing efficiency and printing effect.

Description

Technical Field

[0001] This application relates to the field of 3D printing, and in particular to an exposure control method for a photopolymer 3D printing device, a photopolymer 3D printing device, and a readable storage medium. Background Technology

[0002] 3D printing, also known as additive manufacturing, is a manufacturing technology that uses digital models as a basis to build up material layer by layer to create a physical model. Currently, 3D photopolymerization printing technology is one of the most widely used printing technologies. When the printing platform is below the resin surface in the material tank, the curing light emitted by the light source cures the resin in the tank. The resin in the exposed area cures rapidly, thus completing the process of printing one layer.

[0003] In the aforementioned printing process, after the printed model on the printing platform or the printed model on the printing platform is pressed down onto the release film near the material tank, the waiting time required to expel air from the material to be cured below the platform, or to allow the material to be cured in the material tank to return from a sloshing and flowing state to a near-static state, is called the lamp-off time. Related technologies require users to pre-allocate sufficient, or even excessively long, fixed lamp-off time based on the printing situation to ensure adequate time, which can lead to low printing efficiency. Furthermore, if users lack printing experience and set an insufficient lamp-off time, it may result in poor printing quality or even printing failure. Summary of the Invention

[0004] In view of this, this application provides an exposure control method for a photopolymer 3D printing device, a photopolymer 3D printing device, and a readable storage medium, which enables automatic and accurate determination of the lamp-off time to ensure accurate exposure of the light source module.

[0005] In a first aspect, embodiments of this application provide an exposure control method for a photopolymerization 3D printing device. The photopolymerization 3D printing device includes a printing platform, a material tank, and a light source module. The light source module is used to emit curing light to cure the material to be cured in the material tank and connect it to the printing platform. The method includes:

[0006] Control the printing platform to move to the preset printing position, and keep the light source module in the off state;

[0007] Obtain a first detection value to characterize the flow rate of the material to be cured in the trough;

[0008] When the first detection value is within the preset detection value range, the light source module is controlled to start exposure.

[0009] The method described in the embodiments of this application may also have the following additional technical features:

[0010] Optionally, in the above technical solution, the photopolymerization 3D printing equipment further includes a detection device, which is used to detect a detection value that reflects the flow degree of the material to be cured in the material tank to obtain a second detection value; obtaining the first detection value used to characterize the flow degree of the material to be cured in the material tank includes:

[0011] While the light source module remains in the off state, one or more of the second detection values ​​are acquired;

[0012] The first detection value is determined based on one or more of the second detection values.

[0013] In any of the above technical solutions, optionally, the preset printing position is a position at a preset distance from the bottom of the material tank, the preset distance corresponds to the layer thickness of the current printing layer of the current printing model, and the detection device is a force detection device, which is used to detect the second detection value used to characterize the force on the printing platform and / or the material tank.

[0014] In any of the above technical solutions, optionally, determining the first detection value based on one or more of the second detection values ​​includes:

[0015] The first detection value is determined based on the changes of multiple second detection values ​​over time; or

[0016] The first detection value is determined based on the variance of multiple second detection values ​​obtained within a continuous time period of a fourth preset duration.

[0017] In any of the above technical solutions, optionally, determining the first detection value based on one or more second detection values ​​includes: determining the first detection value based on the changes of multiple second detection values ​​over time; determining the first detection value based on the changes of multiple second detection values ​​over time includes:

[0018] The first difference between the second detection value collected at the first time point and the second detection value collected at the second time point is obtained, wherein the first time point and the second time point are spaced apart by a first preset time period;

[0019] The first detection value is determined based on the first difference.

[0020] In any of the above technical solutions, optionally, controlling the light source module to turn on exposure when the first detection value is within a preset detection value range includes:

[0021] When the absolute value of the first detection value is less than the first threshold, control the light source module to turn on exposure; or

[0022] When the first detected value is less than the first threshold and greater than the third threshold, the light source module is controlled to turn on exposure; the third threshold is a negative number or 0, and the first threshold is a positive number;

[0023] The method further includes:

[0024] When the absolute value of the first detection value is greater than the second threshold, a first prompt message is issued. The first prompt message is used to indicate that the material to be cured is abnormal, and the second threshold is greater than the first threshold.

[0025] In any of the above technical solutions, optionally, after determining the first detection value based on the first difference, the method further includes:

[0026] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the third time point; the third time point is later than the second time point and the first time point on the time axis.

[0027] The second difference between the second detection value collected at the second time point and the second detection value collected at the third time point is obtained, wherein the second time point and the third time point are spaced apart by a second preset time period;

[0028] The first detection value is determined based on the second difference;

[0029] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure;

[0030] And / or, after determining the first detection value based on the first difference, the method further includes:

[0031] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the fourth time point and the second detection value collected at the fifth time point; at least one of the fourth time point and the fifth time point is later than the second time point and the first time point on the time axis.

[0032] The third difference between the second detection value collected at the fourth time point and the second detection value collected at the fifth time point is obtained, wherein the fourth time point and the fifth time point are spaced apart by a third preset time period;

[0033] The first detection value is determined based on the third difference.

[0034] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure.

[0035] Optionally, in any of the above technical solutions, the method further includes:

[0036] Record the total duration for which the printing platform moves to the preset printing position and remains in the off state;

[0037] When the total duration exceeds the preset lamp-off time threshold, a second prompt message is issued. The second prompt message is used to indicate that the detection device is malfunctioning or that the working environment of the photopolymerization 3D printing equipment is malfunctioning.

[0038] Optionally, in any of the above technical solutions, the method further includes:

[0039] Obtain the viscosity of the material to be cured;

[0040] The first threshold is determined based on the viscosity of the material to be cured, and the magnitude of the first threshold is positively correlated with the magnitude of the viscosity.

[0041] Optionally, in any of the above technical solutions, the method further includes:

[0042] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and the size of the first threshold is determined based on the area of ​​the platform connection surface. The size of the first threshold and the size of the platform connection surface area are positively correlated.

[0043] When the printing platform is printing on a layer other than the first layer of the printing model, it obtains the layer area of ​​the layer above the current layer of the current printing model, and determines the size of the first threshold based on the layer area. The size of the first threshold is positively correlated with the size of the layer area.

[0044] Optionally, in any of the above technical solutions, the method further includes:

[0045] Obtain the viscosity of the material to be cured;

[0046] The first coefficient is determined based on the viscosity of the material to be cured;

[0047] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and a second coefficient is determined based on the area of ​​the platform connection surface.

[0048] When the printing platform is on a layer other than the first layer of the printing model, the layer area of ​​the layer above the current layer of the current printing model is obtained, and a third coefficient is determined based on the layer area.

[0049] The size of the first threshold is determined based on the first coefficient and the second coefficient; or the size of the first threshold is determined based on the first coefficient and the third coefficient.

[0050] Optionally, in any of the above technical solutions, before controlling the printing platform to move to the preset printing position, the method further includes:

[0051] Read the detection value from the detection device;

[0052] When the number of times the detection value of the detection device fails to be read is greater than or equal to a preset threshold, a third prompt message is issued, which is used to indicate that the detection device is abnormal.

[0053] After issuing the third prompt message, the method further includes:

[0054] Obtain user feedback information based on the third prompt information;

[0055] When the feedback information is the first feedback information, the detection value of the detection device is reread and the number of times the detection value of the detection device has failed to be read is reset;

[0056] When the feedback information is the second feedback information, a fourth prompt information is issued, which is used to indicate that the photopolymerization 3D printing equipment is malfunctioning.

[0057] Secondly, embodiments of this application provide a photopolymerization 3D printing device, comprising:

[0058] The printing platform is used to connect the printing model;

[0059] A material trough is used to hold the material to be cured.

[0060] A light source module is used to project curing light to cure the material to be cured in the material tank and connect it to the printing platform;

[0061] A memory that stores programs or instructions;

[0062] A processor, which, when executing the program or instructions, implements the steps of the exposure control method for a photopolymerization 3D printing apparatus as described in any one of the first aspects.

[0063] Optionally, in the above technical solution, the device further includes:

[0064] Drive mechanism;

[0065] A vertical motion mechanism is connected to the drive mechanism;

[0066] A cantilever, the first end of which is connected to the printing platform, and the second end of which is connected to the vertical motion mechanism;

[0067] A detection device is disposed on the surface of the cantilever corresponding to the opening position of the cantilever, and the detection device is used to detect the deformation of the cantilever.

[0068] Thirdly, embodiments of this application provide a readable storage medium having a program or instructions stored thereon, which, when executed by a processor, implement the steps of the exposure control method for a photopolymerization 3D printing device as described in any one of the first aspects.

[0069] In this embodiment, the printing platform is controlled to descend, moving to a preset printing position. When the printing platform is at the preset printing position, the light source module is controlled to remain in an off state. The descent of the printing platform causes the material to be cured in the material tank to flow. The degree of flow of the material to be cured is detected, obtaining a first detection value to characterize the degree of flow of the material to be cured in the material tank. It is determined whether the first detection value is within a preset detection value range. When the first detection value is within the preset detection value range, it indicates that the leveling of the material to be cured is basically completed. At this time, the off-light time of the light source module ends, that is, the light source module displays the image and begins exposure. In this way, exposure after the material to be cured has leveled can ensure a better printing effect and printing success rate, and can avoid an excessively long off-light time after the material to be cured has leveled, thereby improving printing efficiency. In this embodiment, the off-light time can be automatically and accurately determined based on the detection value characterizing the degree of flow of the material to be cured in the material tank without having to set the specific off-light time of the light source module in advance based on printing experience. This achieves timely and accurate exposure control of the light source module, improving printing efficiency and printing effect.

[0070] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, specific embodiments of this application are given below. Attached Figure Description

[0071] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0072] Figure 1 A flowchart illustrating the exposure control method of a photopolymerization 3D printing device according to an embodiment of this application is shown.

[0073] Figure 2 A schematic diagram of the structure of a photopolymerization 3D printing device according to an embodiment of this application is shown.

[0074] The correspondence between the reference numerals and component names in the figure is as follows:

[0075] 201 Printing platform, 202 Material trough, 203 Light source module, 204 Vertical motion mechanism, 205 Cantilever, 206 Detection device, 2031 Display screen, 2032 Light source. Detailed Implementation

[0076] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0077] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0078] The following description, in conjunction with the accompanying drawings, details the exposure control method for the photopolymer 3D printing equipment, the photopolymer 3D printing equipment, and the readable storage medium provided in this application, through specific embodiments and application scenarios.

[0079] This application provides an exposure control method for a photopolymerization 3D printing device. The photopolymerization 3D printing device includes a printing platform, a material tank, and a light source module. The light source module is used to emit curing light to cure the material to be cured in the material tank and connect it to the printing platform. Figure 1 As shown, the method includes:

[0080] Step 101: Control the printing platform to move to the preset printing position and keep the light source module in the off state;

[0081] Step 102: Obtain a first detection value to characterize the flow rate of the material to be cured in the trough;

[0082] Step 103: When the first detection value is within the preset detection value range, control the light source module to turn on exposure.

[0083] It should be noted that the curing material in the trough can be cured and connected to the printing platform in two ways: either the curing material in the trough is cured to be directly connected to the printing platform, or the curing material in the trough is cured to be connected to the already printed part of the model, thereby indirectly connecting to the printing platform.

[0084] In this embodiment, during the printing of each layer of the printed model, the printing platform is controlled to descend, moving it to a preset printing position. When the printing platform is at the preset printing position, the light source module is controlled to remain in an off state.

[0085] The descent of the printing platform causes the material to be cured (e.g., resin) to flow within the feed tank. The degree of flow of the material to be cured is detected to obtain a first detection value characterizing the degree of flow of the material to be cured within the feed tank. A high degree of flow indicates that the downward pressure of the printing platform has introduced air into the material to be cured, and the expulsion of this air has resulted in a greater degree of flow. Alternatively, the upward and downward movement of the platform may have agitated the material in the feed tank, causing it to be in a state of significant agitation and flow. A low degree of flow indicates that the air is about to be expelled, and the agitation and flow of the material to be cured is gradually stopping, causing the contact between the material to be cured and the printing platform or the printed model supported on the printing platform to become more consistent.

[0086] Determine whether the first detection value is within the preset detection value range. When the first detection value is within the preset detection value range, it indicates that the leveling of the material to be cured is basically completed, indicating that the contact between the material to be cured and the printing platform or the printing model carried on the printing platform tends to be consistent. The lamp-off time of the light source module ends, the image displayed by the light source module begins to be exposed, realizing the light curing of the current layer, and then performing release to realize the printing of the current layer.

[0087] In one embodiment, if the current layer is the last layer of the printable model, printing the printable model is completed after printing the current layer; if the current layer is not the last layer of the printable model, printing the next layer continues.

[0088] In this embodiment, the user does not need to set the lamp-off time of the light source module. Instead, based on the detection value of the flow degree of the material to be cured in the material tank, the lamp-off time is automatically and accurately determined, achieving timely and accurate exposure of the light source module, thus improving printing efficiency and printing effect. This embodiment can achieve exposure only after confirming that the leveling of the material to be cured is basically completed. It can avoid the material to be cured from shaking, which could cause some of the material to be cured to flow outside the exposure area during the exposure process, resulting in contamination of the material to be cured in the material tank and affecting subsequent printing. It can also avoid the material to be cured from shaking, which could cause the material to be cured in the material tank to flow between the non-exposed area and the exposure area, resulting in the material to be cured not being in the exposure area in the early stage of exposure flowing into the exposure area in the later stage of exposure. This would result in insufficient exposure time for the material to be cured in the exposure area, leading to curing failure, model defects, model breaks, or model peeling. In specific embodiments, the material to be cured can be resin, other liquid materials to be cured, or powdered materials with good flowability.

[0089] Furthermore, the embodiments of this application can also avoid printing failures caused by external environmental disturbances during the lamp-out period. For example, during the lamp-out period, external environmental disturbances—such as table shaking—cause the resin to reflow. Some embodiments of this application can identify that the first detection value caused by the shaking exceeds the preset detection value range, and thus can continue to detect the first detection value until the shaking subsides and the resin returns to calm, so that the first detection value falls within the preset detection value range. This ensures that exposure is performed in a resin-level state, guaranteeing printing quality.

[0090] In one embodiment of this application, the photopolymerization 3D printing equipment further includes a detection device, which is used to detect a detection value that reflects the flowability of the material to be cured in the material tank to obtain a second detection value; obtaining the first detection value for characterizing the flowability of the material to be cured in the material tank includes:

[0091] While the light source module remains in the off state, one or more of the second detection values ​​are acquired;

[0092] The first detection value is determined based on one or more of the second detection values.

[0093] In this embodiment, the photopolymerization 3D printing equipment also includes a detection device, which is used to obtain a detection value reflecting the flow degree of the material to be cured in the material tank, and obtain a second detection value. That is, the second detection value is used to characterize the flow degree of the material to be cured in the material tank.

[0094] When the light source module remains in the off state, one or more second detection values ​​are acquired by the detection device to characterize the flow of the material to be cured in the material tank, and a first detection value is determined based on the one or more second detection values. When there is only one second detection value, the second detection value can be directly used as the first detection value. When there are multiple second detection values, the first detection value can be obtained by calculating the difference, variance, or average value of the second detection values.

[0095] It should be noted that when there is only one second detection value, directly using it as the first detection value means the preset detection value range needs to continuously change as the model printing process continues. This is influenced by factors such as the current layer area of ​​the model, the resin viscosity, and the cumulative weight of the model. Similarly, when there are multiple second detection values, the preset detection value range may also continuously change as the model printing process continues, again influenced by factors such as the current layer area of ​​the model and the resin viscosity.

[0096] In this embodiment, a detection device is set on the photopolymerization 3D printing equipment to obtain the flow degree of the material to be cured in the material tank, thereby automatically determining the lamp-off time of the light source module based on the flow degree of the material to be cured in the material tank, ensuring accurate exposure of the light source module.

[0097] In one embodiment of this application, the preset printing position is a position at a preset distance from the bottom of the material tank, the preset distance corresponding to the layer thickness of the current printing layer of the current printing model, and the detection device is a force detection device, which is used to detect the second detection value for characterizing the force on the printing platform and / or the material tank.

[0098] In this embodiment, the preset printing position is a position at a preset distance from the bottom of the material tank. The bottom of the material tank houses a screen containing a light source module. Therefore, the preset printing position is equivalent to the printing platform descending to a position at a preset distance from the screen. Furthermore, it should be noted that the preset distance depends on the thickness of the current printing layer of the current printing model. This is because, during the printing of the current layer, the distance between the lower surface of the printing platform or the lower surface of the formed printing model carried by the printing platform and the screen needs to be controlled according to the thickness of the current printing layer. For example, if the thickness of the current printing layer is 'a', then the distance between the lower surface of the printing platform or the lower surface of the formed printing model carried by the printing platform and the screen is controlled to be 'a', which is the preset distance at this time.

[0099] In one embodiment, the detection device can be a force detection device, a deformation detection device, etc., capable of detecting the deformation of a specific component at a specific location and other physical quantities that can represent changes in force, such as tension, gravity, pressure, and torque. Specifically, it can be an elastic resistance strain gauge, a tensile sensor, or other devices that detect changes in force. In some embodiments, the detection device is mounted on the cantilever, specifically attached to the upper surface of the cantilever, and can detect the deformation of the cantilever, which reflects the force on the printing platform.

[0100] In some implementations, the detection device is located on the bottom wall or other position of the material tank of the photopolymerization 3D printing equipment to detect the stress on the material tank.

[0101] Alternatively, the detection device can be a photoelectric detection device or an image detection device, which can detect deformation. For example, an image detection device includes a camera and an image analysis device. The camera is used to acquire images of the cantilever, and the image analysis device analyzes the deformation and stress of the cantilever through the images. The placement of the image analysis device on the photopolymerization 3D printing equipment is not limited, as long as it can capture clear images of the cantilever.

[0102] Alternatively, the detection device can also be equipped with other types of sensors for detecting the flow of the material to be cured, such as a flow sensor, which can be set on the side wall of the trough. When the material to be cured flows through the flow sensor, it will convert the flow rate of the material to be cured into voltage or current, thereby realizing real-time monitoring of the flow rate.

[0103] This application can accurately determine the flow of the material to be cured based on the detection value of the detection device, thereby determining the lamp-off time and improving printing efficiency and printing effect.

[0104] In one embodiment of this application, determining the first detection value based on one or more second detection values ​​includes:

[0105] The first detection value is determined based on the changes of multiple second detection values ​​over time.

[0106] In this embodiment, a first detection value is determined based on the changes of multiple second detection values ​​over time. In other words, the first detection value reflects the changes in the flow of the material to be cured over a period of time, i.e., the degree of flow.

[0107] In this embodiment, the flowability of the material to be cured is determined by multiple second detection values ​​that change over time. Compared with using a single detection value to determine the flowability of the material to be cured, this improves the accuracy of the flowability of the material to be cured, thereby improving the accuracy of exposure control of the light source module.

[0108] In one embodiment of this application, determining a first detection value based on one or more second detection values ​​includes:

[0109] The first detection value is determined based on the variance of multiple second detection values ​​obtained within a continuous time period of the fourth preset duration.

[0110] For example, 30 second detection values ​​are acquired within a continuous time period of 0.5s or 1s. The variance of these 30 second detection values ​​is then calculated, and this variance is used as the first detection value, or the variance is normalized or transformed using a function and then used as the first detection value. This accurately reflects the changes in the second detection values ​​within a continuous time period of 1s, that is, it accurately reflects the changes in the flow rate of the material to be cured in the trough. Therefore, when the first detection value is less than a first threshold, confirming that the change in the flow rate of the material to be cured in the trough is small within a continuous time period, it is determined that resin leveling is complete, and the contact between the resin and the printing platform or the printed model supported on the printing platform tends to be consistent. This determines the end of the lamp-off time, controls the light source module to start exposure, and automatically and accurately determines the lamp-off time, achieving accurate exposure of the light source module, improving printing efficiency and printing effect.

[0111] In one embodiment of this application, determining the first detection value based on one or more second detection values ​​includes: determining the first detection value based on the changes of a plurality of second detection values ​​over time; determining the first detection value based on the changes of a plurality of second detection values ​​over time includes:

[0112] The first difference between the second detection value collected at the first time point and the second detection value collected at the second time point is obtained, wherein the first time point and the second time point are spaced apart by a first preset time period;

[0113] The first detection value is determined based on the first difference.

[0114] In this embodiment, the printing platform is controlled to descend to a preset printing position, and the light source module is kept in an off state. The second detection value b1 collected by the detection device at a first time point is read, and after a first preset time delay, the second detection value b2 collected by the detection device at a second time point is read. The first preset time delay can range from 0.1s to 1s. The difference between the second detection value b2 and the second detection value b1 is calculated to obtain a first difference m1. This difference reflects the flow of the material to be cured within the first preset time delay. The first detection value is then determined based on the first difference m1.

[0115] In some embodiments, the first difference can be directly used as the first detection value, or the first difference can be transformed by a function to obtain the first detection value.

[0116] In this embodiment, the difference between two detection values ​​spaced a first preset time interval is used to characterize the flow of the material to be cured, and then used to determine the lamp-off time, thereby improving the accuracy of the light source module exposure.

[0117] In one embodiment of this application, controlling the light source module to turn on exposure when the first detection value is within a preset detection value range includes:

[0118] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure;

[0119] The method further includes:

[0120] When the absolute value of the first detection value is greater than the second threshold, a first prompt message is issued. The first prompt message is used to indicate that the material to be cured is abnormal, and the second threshold is greater than the first threshold.

[0121] In this embodiment, the absolute value of the first detection value is compared with a first threshold to determine whether the absolute value of the first detection value is less than the first threshold, which is used to determine whether the material to be cured has become static. If the absolute value of the first detection value is less than the first threshold, it indicates that the flow of the material to be cured in the tank is small and has become static, meaning that the material to be cured has completed its backflow, and the preset detection value range is the range less than the first threshold. At this time, the lamp-off time ends, and the light source module is controlled to start exposure to achieve the curing of the material to be cured.

[0122] In one implementation, the absolute value of a first detection value is compared with a second threshold. When the absolute value of the first detection value is greater than the second threshold, it indicates a large difference between the two detection values ​​spaced a first preset time interval. For example, the second detection value b1 collected at the first time point is larger, while the second detection value b2 collected at the second time point is smaller. This situation may be due to the presence of printed model residue in the material to be cured in the curing tank at the second time point, resulting in a significant reduction in the flow of the material to be cured from a detection perspective. However, in reality, this significant reduction in the flow of the material to be cured does not necessarily mean resin leveling, but should be considered an abnormal situation. Therefore, in this case, a first prompt message is issued to remind the user of the abnormality of the material to be cured, ensuring that the user can take effective measures in a timely manner, such as cleaning model residue, to ensure the smooth progress of subsequent printing.

[0123] In one embodiment of this application, controlling the light source module to turn on exposure when the first detection value is within a preset detection value range includes:

[0124] When the first detected value is less than the first threshold and greater than the third threshold, the light source module is controlled to turn on exposure; the third threshold is a negative number or 0, and the first threshold is a positive number;

[0125] In this embodiment, when the third threshold is 0, the second detection value caused by the abnormality of the detection device can be kept stable, so that the first detection value is always calculated as 0, and the abnormality of the detection device cannot accurately determine whether the resin flow is complete. This prevents the misjudgment of resin leveling caused by the abnormality of the detection device, and improves the control accuracy of the end time of lamp extinguishing.

[0126] In this embodiment, when the third threshold is negative, the first detection value can be understood as the difference between the second detection value collected at the first time point and the second detection value collected at the second time point. This difference may be positive or negative due to resin flow fluctuations. In this embodiment, the first detection value is not taken as an absolute value, but is judged according to the range between the negative third threshold and the positive first threshold. This facilitates more personalized algorithm optimization design, making the determination of the resin leveling completion time point more accurate and improving the printing effect.

[0127] In one embodiment of this application, after determining the first detection value based on the first difference, the method further includes:

[0128] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the third time point; the third time point is later than the second time point and the first time point on the time axis.

[0129] The second difference between the second detection value collected at the second time point and the second detection value collected at the third time point is obtained, wherein the second time point and the third time point are spaced apart by a second preset time period;

[0130] The first detection value is determined based on the second difference;

[0131] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure;

[0132] And / or, after determining the first detection value based on the first difference, the method further includes:

[0133] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the fourth time point and the second detection value collected at the fifth time point; at least one of the fourth time point and the fifth time point is later than the second time point and the first time point on the time axis.

[0134] The third difference between the second detection value collected at the fourth time point and the second detection value collected at the fifth time point is obtained, wherein the fourth time point and the fifth time point are spaced apart by a third preset time period;

[0135] The first detection value is determined based on the third difference.

[0136] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure.

[0137] In one implementation, when the absolute value of the first detection value is greater than or equal to a first threshold and less than a second threshold, it indicates that the material to be cured in the tank has a high degree of flow and has not yet settled, meaning that the reflow has not been completed. At this time, starting from the second time point, after a second preset time delay, the second detection value b3 collected by the detection device at the third time point is read again, where the second preset time can range from 0.1s to 1s. The difference between the second detection value b3 and the second detection value b2 is calculated to obtain a second difference m2, and then the first detection value is re-determined based on the second difference m2. Then, the re-determined first detection value is compared with the first threshold. When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to start exposure. In other words, when the absolute value of the first detection value is greater than or equal to the first threshold, a second detection value b3 is re-read, and the re-read second detection value b3 and the previously read second detection value b2 are used to determine the first detection value, thereby minimizing the number of times the detection device reads the data and reducing power consumption.

[0138] In another implementation, when the absolute value of the first detection value is greater than or equal to the first threshold and less than the second threshold, the second detection value b4 collected by the detection device at the fourth time point is read, and after a delay of the third preset time period, the second detection value b5 collected by the detection device at the fifth time point is read again, where the value of the third preset time period can be in the range of 0.1s to 1s. The difference between the second detection value b5 and the second detection value b4 is calculated to obtain the third difference m3, and then the first detection value is re-determined based on the third difference m3. Then, the re-determined first detection value is compared with the first threshold. When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to start exposure. That is, when the absolute value of the first detection value is greater than or equal to the first threshold, two second detection values ​​b4 and two second detection values ​​b5 are re-read, and the first detection value is determined using the re-read second detection values ​​b4 and b5. Determining the first detection value using the two re-read second detection values ​​can improve the accuracy of the determined first detection value.

[0139] Furthermore, in both of the above embodiments, a preset time delay is required before continuing to read the second detection value. By delaying the reading of the detection value, it can be ensured that the material to be cured has a sufficiently long time to tend to remain still.

[0140] In one embodiment of this application, the method further includes:

[0141] Record the total duration for which the printing platform moves to the preset printing position and remains in the off state;

[0142] When the total duration exceeds the preset lamp-off time threshold, a second prompt message is issued. The second prompt message is used to indicate that the detection device is malfunctioning or that the working environment of the photopolymerization 3D printing equipment is malfunctioning.

[0143] In some embodiments, the second prompt message is used to indicate an abnormality in the detection device. It records the total time the printing platform remains in an off-state after moving to the preset printing position. This total time represents the duration during which the material to be cured is in a state of high fluidity. When this total time exceeds a preset off-state time threshold, it indicates that the material to be cured in the material tank has not settled for an extended period. This may indicate an abnormality in the detection device, and a prompt is sent to the user to remind them to repair or replace the detection device promptly to ensure smooth printing.

[0144] In some embodiments, the second prompt message is used to indicate that the working environment of the photopolymer 3D printing device is abnormal. When the total time that the printing platform remains in the off state after moving to the preset printing position exceeds the preset off time threshold, it may be due to a problem with the flow of the material to be cured, such as a large and continuous shaking of the table on which the photopolymer 3D printing device is placed. Therefore, the second prompt message can also be used to indicate abnormal flow of the material to be cured, so as to remind the user to take corresponding measures in time to ensure the smooth progress of printing.

[0145] Of course, in some implementations, the second prompt message may also list the following: it may be that the detection device is malfunctioning or that the working environment of the photopolymer 3D printing equipment is abnormal, and suggest that the user perform corresponding operations to further determine the source of the abnormality.

[0146] In one embodiment of this application, the method further includes:

[0147] Obtain the viscosity of the material to be cured;

[0148] The first threshold is determined based on the viscosity of the material to be cured, and the magnitude of the first threshold is positively correlated with the magnitude of the viscosity.

[0149] In this embodiment, the first threshold can be determined based on the viscosity of the material to be cured. Specifically, the higher the viscosity of the material to be cured, the lower its flow rate, the greater the resin resistance, and the greater the force detected by the detection device. Therefore, the corresponding first threshold should be set higher.

[0150] By using the above method, the first threshold is determined based on the viscosity of the material to be cured used during printing, making the judgment of the flowability of the material to be cured more consistent with the actual printing scenario, and further improving the accuracy of the lamp-off time.

[0151] In one embodiment of this application, the method further includes:

[0152] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and the size of the first threshold is determined based on the area of ​​the platform connection surface. The size of the first threshold and the size of the platform connection surface area are positively correlated.

[0153] When the printing platform is printing on a layer other than the first layer of the printing model, it obtains the layer area of ​​the layer above the current layer of the current printing model, and determines the size of the first threshold based on the layer area. The size of the first threshold is positively correlated with the size of the layer area.

[0154] In this embodiment, the first threshold can be determined based on the platform connection surface area of ​​the printing platform or the layer area of ​​the printed model. Specifically, when the printing platform is on the first layer of the printed model, the first threshold is determined based on the platform connection surface area of ​​the surface of the printing platform used to connect the printed model; when the printing platform is on other layers besides the first layer of the printed model, the first threshold is determined based on the layer area of ​​the layer above the current layer of the current printed model.

[0155] The larger the platform connection area of ​​the printing platform or the layer area of ​​the printed model, the greater the flow of the material to be cured after the printing platform or the printed model it supports presses down into the feed chute. Therefore, to accurately detect when the material to be cured tends to be stationary, the first threshold needs to be set larger. Conversely, the smaller the platform connection area of ​​the printing platform or the layer area of ​​the printed model, the smaller the first threshold needs to be. In other words, the size of the first threshold is positively correlated with the size of the platform connection area of ​​the printing platform or the layer area of ​​the printed model.

[0156] By using the above method, the first threshold is determined based on the actual printing platform's connection surface area or the layer area of ​​the printed model, making the judgment of the flow degree of the material to be cured more consistent with the actual printing scenario and further improving the accuracy of the lamp-off time.

[0157] In one embodiment of this application, the method further includes:

[0158] Obtain the viscosity of the material to be cured;

[0159] The first coefficient is determined based on the viscosity of the material to be cured;

[0160] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and a second coefficient is determined based on the area of ​​the platform connection surface.

[0161] When the printing platform is on a layer other than the first layer of the printing model, the layer area of ​​the layer above the current layer of the current printing model is obtained, and a third coefficient is determined based on the layer area.

[0162] The size of the first threshold is determined based on the first coefficient and the second coefficient; or the size of the first threshold is determined based on the first coefficient and the third coefficient.

[0163] In this embodiment, the viscosity of the material to be cured is obtained, and a first coefficient is determined based on the viscosity of the material to be cured.

[0164] When the printing platform is on the first layer of the printed model, the area of ​​the platform connection surface used to connect the printed model is obtained. A second coefficient is determined based on the platform connection surface area. A first threshold is determined based on the first and second coefficients. The size of the first threshold is positively correlated with the viscosity and the platform connection surface area. The first coefficient represents the weighting factor of the viscosity of the material to be cured when determining the first threshold using the viscosity and the platform connection surface area, while the second coefficient represents the weighting factor of the platform connection surface area.

[0165] Alternatively, when the printing platform is on a layer other than the first layer of the printing model, the layer area of ​​the layer preceding the current layer of the current printing model is obtained, and a third coefficient is determined based on the layer area of ​​the preceding layer. The first threshold is then determined based on the first and third coefficients, where the magnitude of the first threshold is positively correlated with both the viscosity and the layer area of ​​the preceding layer. The first coefficient represents the weighting factor of the viscosity of the material to be cured when determining the first threshold using the viscosity of the material to be cured and the layer area of ​​the preceding layer, while the third coefficient represents the weighting factor of the layer area of ​​the preceding layer.

[0166] In this embodiment, the first threshold is determined by the viscosity of the material to be cured and the area of ​​the platform connection surface or the area of ​​the upper layer, so that the judgment of the flow degree of the material to be cured is more in line with the actual printing scenario, and further improves the accuracy of the lamp-off time.

[0167] In one embodiment of this application, before controlling the printing platform to move to the preset printing position, the method further includes:

[0168] Read the detection value from the detection device;

[0169] When the number of times the detection value of the detection device fails to be read is greater than or equal to a preset threshold, a third prompt message is issued, which is used to indicate that the detection device is abnormal.

[0170] After issuing the third prompt message, the method further includes:

[0171] Obtain user feedback information based on the third prompt information;

[0172] When the feedback information is the first feedback information, the detection value of the detection device is reread and the number of times the detection value of the detection device has failed to be read is reset;

[0173] When the feedback information is the second feedback information, a fourth prompt information is issued, which is used to indicate that the photopolymerization 3D printing equipment is malfunctioning.

[0174] In this embodiment, an anomaly detection is performed on the detection device before controlling the light-off time. Specifically, the detection device's detection value is read. If no value is read, the reading continues until the number of reads is greater than or equal to a preset number (e.g., 10 times). If so, the detection device is determined to be abnormal, and a third prompt message is issued to indicate the anomaly. This application can detect anomalies in the detection device and issue timely reminders to inform the user of the anomaly.

[0175] Furthermore, the detection device is only deemed abnormal after multiple failures to read the detection value, thus avoiding the problem of misjudgment on the first attempt and improving the reliability of the determination of abnormal conditions of the detection device.

[0176] In some embodiments, the third prompt message may be used to generally indicate that the photopolymer 3D printing equipment is malfunctioning, or to indicate that the detection device is damaged and suggests replacing the detection device, or to suggest contacting customer service for assistance, or to suggest restarting the photopolymer 3D printing equipment; no specific limitations are made here.

[0177] In one embodiment, after receiving a third notification, the user understands that the detection device has malfunctioned and will take measures to replace the detection device. The user will then provide feedback on the replacement detection device through the interactive device of the photopolymer 3D printing equipment. After receiving the user's feedback, the system decides whether to continue malfunction detection on the newly replaced detection device, thus achieving interaction with the user and improving printing efficiency.

[0178] This application also provides a photopolymerization 3D printing device, such as... Figure 2 As shown, the device includes:

[0179] Printing platform 201 is used to connect the printing model;

[0180] Material tank 202 is used to hold the material to be cured;

[0181] The light source module 203 is used to project curing light to cure the material to be cured in the material tank 202 and connect it to the printing platform 201;

[0182] A memory (not shown in the figure) that stores programs or instructions;

[0183] The processor (not shown in the figure) executes the program or instructions to implement the various steps of the exposure control method of the photopolymerization 3D printing device described above, and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0184] In one embodiment of this application, the device further includes:

[0185] Drive mechanism (not shown in the figure);

[0186] The vertical motion mechanism 204 is connected to the drive mechanism;

[0187] The cantilever 205 has a first end connected to the printing platform 201 and a second end connected to the vertical motion mechanism 204.

[0188] The detection device 206 is disposed on the surface of the cantilever 205 corresponding to the opening position of the cantilever 205, and the detection device 206 is used to detect the deformation of the cantilever 205.

[0189] The first end of the cantilever 205 is used to mount the printing platform 201, and the second end of the cantilever 205 is connected to the vertical motion mechanism 204. The vertical motion mechanism 204 can drive the cantilever 205 and the printing platform 201 to move relative to one side of the material tank 202 to print the model. The display screen 2031 of the light source module 203 is located on the other side of the material tank 202.

[0190] In one embodiment, the light source module 203 includes a display screen 2031 and a light source 2032. The light source 2032 is disposed on one side of the display screen 2031. The display screen 2031 is used to display a pattern with a specific outline. The light from the light source 2032 passes through the pattern and is projected onto the release film at the bottom of the material tank 202, so that the material to be cured between the printing platform 201 and the release film is cured and attached to the surface of the printing platform 201.

[0191] The detection device 206 can be a force detection device, deformation detection device, etc., capable of detecting the deformation of a specific component at a specific location and other physical quantities that can represent changes in force, such as tension, gravity, pressure, and torque. Specifically, it can be an elastic resistance strain gauge, a tension sensor, or other devices that detect changes in force. In some embodiments, the detection device 206 is disposed on the cantilever 205, specifically attached to the upper surface of the cantilever 205, and can detect the deformation of the cantilever 205. The deformation of the cantilever 205 reflects the force on the printing platform 201. After the printing platform 201 is mounted on the cantilever 205, the printing platform 201 will exert a pulling force on the cantilever 205, causing slight deformation of the cantilever 205. Furthermore, when the printing platform receives tension or thrust, it will also affect the force on the cantilever 205. Therefore, the detection value of the detection device 206 indirectly characterizes the force on the printing platform 201.

[0192] In some embodiments, the detection device 206 can be connected to a measuring circuit and a voltmeter. The detection device 206 and the measuring circuit form a Wheatstone bridge to obtain the output voltage of the voltmeter. By the relationship between the output voltage and the force, the corresponding detection value, i.e. the force value, can be calculated.

[0193] In this embodiment, the user does not need to set the lamp-off time of the light source module. Instead, based on the first detection value of the detection device, the flow rate of the material to be cured in the material tank is determined, thereby automatically and accurately determining the lamp-off time, achieving accurate exposure of the light source module, and improving printing efficiency and printing effect.

[0194] This application also provides a readable storage medium storing a program or instructions that, when executed by a processor, implement the various steps of the exposure control method of the photopolymerization 3D printing device described above, and achieve the same technical effect. To avoid repetition, it will not be described again here.

[0195] This application also provides the following embodiments:

[0196] Reference numeral 1, this application provides an exposure control method for a photopolymerization 3D printing device. The photopolymerization 3D printing device includes a printing platform, a material tank, and a light source module. The light source module is used to emit curing light to cure the material to be cured in the material tank and connect it to the printing platform. The method includes:

[0197] Control the printing platform to move to the preset printing position, and keep the light source module in the off state;

[0198] Obtain a first detection value to characterize the flow rate of the material to be cured in the trough;

[0199] When the first detection value is within the preset detection value range, the light source module is controlled to start exposure.

[0200] Reference numeral 2, based on reference numeral 1, further includes a detection device on the photopolymerization 3D printing equipment. This detection device is used to detect a second detection value that reflects the flowability of the material to be cured within the material tank. Obtaining the first detection value characterizing the flowability of the material to be cured within the material tank includes:

[0201] While the light source module remains in the off state, one or more of the second detection values ​​are acquired;

[0202] The first detection value is determined based on one or more of the second detection values.

[0203] Reference numeral 3, based on reference numeral 2 or any of the above embodiments, the preset printing position is a position at a preset distance from the bottom of the material trough, the preset distance corresponding to the layer thickness of the current printing layer of the current printing model, the detection device is a force detection device, the force detection device is used to detect the second detection value used to characterize the force on the printing platform and / or the material trough.

[0204] Reference numeral 4, based on reference numeral 2 or any of the above embodiments, the step of determining the first detection value based on one or more of the second detection values ​​includes:

[0205] The first detection value is determined based on the changes of multiple second detection values ​​over time; or

[0206] The first detection value is determined based on the variance of multiple second detection values ​​obtained within a continuous time period of a fourth preset duration.

[0207] Reference numeral 5, based on reference numeral 4 or any of the above embodiments, the step of determining the first detection value based on one or more second detection values ​​includes: determining the first detection value based on the changes of multiple second detection values ​​over time; the step of determining the first detection value based on the changes of multiple second detection values ​​over time includes:

[0208] The first difference between the second detection value collected at the first time point and the second detection value collected at the second time point is obtained, wherein the first time point and the second time point are spaced apart by a first preset time period;

[0209] The first detection value is determined based on the first difference.

[0210] Reference numeral 6, based on reference numeral 5 or any of the above embodiments, the step of controlling the light source module to start exposure when the first detection value is within a preset detection value range includes:

[0211] When the absolute value of the first detection value is less than the first threshold, control the light source module to turn on exposure; or

[0212] When the first detected value is less than the first threshold and greater than the third threshold, the light source module is controlled to turn on exposure; the third threshold is a negative number or 0, and the first threshold is a positive number;

[0213] The method further includes:

[0214] When the absolute value of the first detection value is greater than the second threshold, a first prompt message is issued. The first prompt message is used to indicate that the material to be cured is abnormal, and the second threshold is greater than the first threshold.

[0215] Based on 6 or any of the above embodiments, after determining the first detection value according to the first difference, the method further includes:

[0216] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the third time point; the third time point is later than the second time point and the first time point on the time axis.

[0217] The second difference between the second detection value collected at the second time point and the second detection value collected at the third time point is obtained, wherein the second time point and the third time point are spaced apart by a second preset time period;

[0218] The first detection value is determined based on the second difference;

[0219] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure;

[0220] And / or, after determining the first detection value based on the first difference, the method further includes:

[0221] When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the fourth time point and the second detection value collected at the fifth time point; at least one of the fourth time point and the fifth time point is later than the second time point and the first time point on the time axis.

[0222] The third difference between the second detection value collected at the fourth time point and the second detection value collected at the fifth time point is obtained, wherein the fourth time point and the fifth time point are spaced apart by a third preset time period;

[0223] The first detection value is determined based on the third difference.

[0224] When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure.

[0225] Reference numeral 8, based on reference numeral 7 or any of the above embodiments, the method further includes:

[0226] Record the total duration for which the printing platform moves to the preset printing position and remains in the off state;

[0227] When the total duration exceeds the preset lamp-off time threshold, a second prompt message is issued. The second prompt message is used to indicate that the detection device is malfunctioning or that the working environment of the photopolymerization 3D printing equipment is malfunctioning.

[0228] Reference numeral 9, based on reference numeral 6 or any of the above embodiments, the method further includes:

[0229] Obtain the viscosity of the material to be cured;

[0230] The first threshold is determined based on the viscosity of the material to be cured, and the magnitude of the first threshold is positively correlated with the magnitude of the viscosity.

[0231] Reference numeral 10, based on reference numeral 6 or any of the above embodiments, the method further includes:

[0232] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and the size of the first threshold is determined based on the area of ​​the platform connection surface. The size of the first threshold and the size of the platform connection surface area are positively correlated.

[0233] When the printing platform is printing on a layer other than the first layer of the printing model, it obtains the layer area of ​​the layer above the current layer of the current printing model, and determines the size of the first threshold based on the layer area. The size of the first threshold is positively correlated with the size of the layer area.

[0234] Reference numeral 11, based on reference numeral 6 or any of the above embodiments, the method further includes:

[0235] Obtain the viscosity of the material to be cured;

[0236] The first coefficient is determined based on the viscosity of the material to be cured;

[0237] When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and a second coefficient is determined based on the area of ​​the platform connection surface.

[0238] When the printing platform is on a layer other than the first layer of the printing model, the layer area of ​​the layer above the current layer of the current printing model is obtained, and a third coefficient is determined based on the layer area.

[0239] The size of the first threshold is determined based on the first coefficient and the second coefficient; or the size of the first threshold is determined based on the first coefficient and the third coefficient.

[0240] Reference numeral 12, based on reference numeral 2 or any of the above embodiments, further includes, before controlling the printing platform to move to the preset printing position:

[0241] Read the detection value from the detection device;

[0242] When the number of times the detection value of the detection device fails to be read is greater than or equal to a preset threshold, a third prompt message is issued, which is used to indicate that the detection device is abnormal.

[0243] After issuing the third prompt message, the method further includes:

[0244] Obtain user feedback information based on the third prompt information;

[0245] When the feedback information is the first feedback information, the detection value of the detection device is reread and the number of times the detection value of the detection device has failed to be read is reset;

[0246] When the feedback information is the second feedback information, a fourth prompt information is issued, which is used to indicate that the photopolymerization 3D printing equipment is malfunctioning.

[0247] This application also provides the following embodiments:

[0248] Reference numeral 13, an embodiment of this application provides a photopolymerization 3D printing device, comprising:

[0249] The printing platform is used to connect the printing model;

[0250] A material trough is used to hold the material to be cured.

[0251] A light source module is used to project curing light to cure the material to be cured in the material tank and connect it to the printing platform;

[0252] A memory that stores programs or instructions;

[0253] A processor, which, when executing the program or instructions, implements the steps of an exposure control method for a photopolymerization 3D printing apparatus as described in any one of reference numerals 1 to 12.

[0254] Label 14, in addition to label 13, also includes:

[0255] Drive mechanism;

[0256] A vertical motion mechanism is connected to the drive mechanism;

[0257] A cantilever, the first end of which is connected to the printing platform, and the second end of which is connected to the vertical motion mechanism;

[0258] A detection device is disposed on the surface of the cantilever corresponding to the opening position of the cantilever, and the detection device is used to detect the deformation of the cantilever.

[0259] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An exposure control method for a light-curing three-dimensional printing apparatus, characterized by, The photopolymerization 3D printing equipment includes a printing platform, a material tank, and a light source module. The light source module is used to emit curing light to cure the material to be cured in the material tank and connect it to the printing platform. The method includes: When printing the printing layer of the printing model, the printing platform is controlled to move to the preset printing position, and the light source module is kept in the off state; Obtain a first detection value to characterize the flow rate of the material to be cured in the trough; When the first detection value is within the preset detection value range, the light source module is controlled to start exposure.

2. The method of claim 1, wherein, The photopolymerization 3D printing equipment also includes a detection device, which is used to detect a second detection value that reflects the flow rate of the material to be cured in the material tank. The acquisition of a first detection value for characterizing the flowability of the material to be cured in the trough includes: While the light source module remains in the off state, one or more of the second detection values ​​are acquired; The first detection value is determined based on one or more of the second detection values.

3. The method of claim 2, wherein, The preset printing position is a position at a preset distance from the bottom of the material tank, and the preset distance corresponds to the layer thickness of the current printing layer of the current printing model. The detection device is a force detection device, which is used to detect the second detection value used to characterize the force on the printing platform and / or the material tank.

4. The method of claim 2, wherein, Determining the first detection value based on one or more of the second detection values ​​includes: The first detection value is determined based on the changes of multiple second detection values ​​over time; or The first detection value is determined based on the variance of multiple second detection values ​​obtained within a continuous time period of a fourth preset duration.

5. The method of claim 4, wherein, Determining the first detection value based on one or more second detection values ​​includes: determining the first detection value based on the changes of multiple second detection values ​​over time; determining the first detection value based on the changes of multiple second detection values ​​over time includes: The first difference between the second detection value collected at the first time point and the second detection value collected at the second time point is obtained, wherein the first time point and the second time point are spaced apart by a first preset time period; The first detection value is determined based on the first difference.

6. The method of claim 5, wherein, When the first detection value is within a preset detection value range, controlling the light source module to start exposure includes: When the absolute value of the first detection value is less than the first threshold, control the light source module to turn on exposure; or When the first detected value is less than the first threshold and greater than the third threshold, the light source module is controlled to turn on exposure; the third threshold is a negative number or 0, and the first threshold is a positive number; The method further includes: When the absolute value of the first detection value is greater than the second threshold, a first prompt message is issued. The first prompt message is used to indicate that the material to be cured is abnormal, and the second threshold is greater than the first threshold.

7. The method of claim 6, wherein, After determining the first detection value based on the first difference, the method further includes: When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the third time point; the third time point is later than the second time point and the first time point on the time axis. The second difference between the second detection value collected at the second time point and the second detection value collected at the third time point is obtained, wherein the second time point and the third time point are spaced apart by a second preset time period; The first detection value is determined based on the second difference; When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure; And / or, after determining the first detection value based on the first difference, the method further includes: When the absolute value of the first detection value is greater than or equal to the first threshold, wait for and acquire the second detection value collected at the fourth time point and the second detection value collected at the fifth time point; at least one of the fourth time point and the fifth time point is later than the second time point and the first time point on the time axis. The third difference between the second detection value collected at the fourth time point and the second detection value collected at the fifth time point is obtained, wherein the fourth time point and the fifth time point are spaced apart by a third preset time period; The first detection value is determined based on the third difference. When the absolute value of the first detection value is less than the first threshold, the light source module is controlled to turn on exposure.

8. The method of claim 7, wherein, The method further includes: Record the total duration for which the printing platform moves to the preset printing position and remains in the off state; When the total duration exceeds the preset lamp-off time threshold, a second prompt message is issued. The second prompt message is used to indicate that the detection device is malfunctioning or that the working environment of the photopolymerization 3D printing equipment is malfunctioning.

9. The method of claim 6, wherein, The method further includes: Obtain the viscosity of the material to be cured; The first threshold is determined based on the viscosity of the material to be cured, and the magnitude of the first threshold is positively correlated with the magnitude of the viscosity.

10. The method of claim 6, wherein, The method further includes: When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and the size of the first threshold is determined based on the area of ​​the platform connection surface. The size of the first threshold and the size of the platform connection surface area are positively correlated. When the printing platform is printing on a layer other than the first layer of the printing model, it obtains the layer area of ​​the layer above the current layer of the current printing model, and determines the size of the first threshold based on the layer area. The size of the first threshold is positively correlated with the size of the layer area.

11. The method of claim 6, wherein, The method further includes: Obtain the viscosity of the material to be cured; The first coefficient is determined based on the viscosity of the material to be cured; When the printing platform is on the first layer of the printing model, the area of ​​the platform connection surface used to connect the printing model is obtained, and a second coefficient is determined based on the area of ​​the platform connection surface. When the printing platform is on a layer other than the first layer of the printing model, the layer area of ​​the layer above the current layer of the current printing model is obtained, and a third coefficient is determined based on the layer area. The size of the first threshold is determined based on the first coefficient and the second coefficient; or the size of the first threshold is determined based on the first coefficient and the third coefficient.

12. The method according to any one of claims 2 to 11, characterized in that, Before controlling the printing platform to move to the preset printing position, the method further includes: Read the detection value from the detection device; When the number of times the detection value of the detection device fails to be read is greater than or equal to a preset threshold, a third prompt message is issued, which is used to indicate that the detection device is abnormal. After issuing the third prompt message, the method further includes: Obtain user feedback information based on the third prompt information; When the feedback information is the first feedback information, the detection value of the detection device is reread and the number of times the detection value of the detection device has failed to be read is reset; When the feedback information is the second feedback information, a fourth prompt information is issued, which is used to indicate that the photopolymerization 3D printing equipment is malfunctioning.

13. A light-cured three-dimensional printing apparatus, characterized by, include: The printing platform is used to connect the printing model; A material trough is used to hold the material to be cured. A light source module is used to project curing light to cure the material to be cured in the material tank and connect it to the printing platform; A memory that stores programs or instructions; A processor that, when executing the program or instructions, implements the steps of the exposure control method for a photopolymerization 3D printing apparatus as described in any one of claims 1 to 12.

14. The apparatus of claim 13, wherein, Also includes: Drive mechanism; A vertical motion mechanism is connected to the drive mechanism; A cantilever, the first end of which is connected to the printing platform, and the second end of which is connected to the vertical motion mechanism; A detection device is disposed on the surface of the cantilever corresponding to the opening position of the cantilever, and the detection device is used to detect the deformation of the cantilever.

15. A readable storage medium, on which a program or instructions are stored, characterized in that, When the program or instructions are executed by the processor, they implement the steps of the exposure control method for the photopolymerization 3D printing apparatus as described in any one of claims 1 to 12.

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