Liquid level regulation method, system, and 3D printing device and printing method adapted thereto

Abstract

The application discloses a liquid level adjusting method, a system, and a 3D printing device and a printing method applicable to the liquid level adjusting method. The liquid level adjusting method comprises the following steps: determining a liquid level height adjusting value corresponding to at least one printing layer according to a volume change of a bearing mechanism immersed in a photocuring material during a printing process of the at least one printing layer; and adjusting a liquid level height of the photocuring material in a container based on the liquid level height adjusting value, and keeping the liquid level height in a reference liquid level height interval. The application does not directly rely on detection data of a detection device to adjust the liquid level, thereby avoiding errors caused by uneven liquid surface. The application takes the volume change of the bearing mechanism immersed in the photocuring material as a main input and frequently adjusts the liquid level, so that a flow leveling time of the adjusted liquid surface is shorter, liquid surface fluctuation is small, printing efficiency and precision are improved, and printing quality is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, in particular to a liquid level adjusting method and system, and a 3D printing device and printing method applicable thereto. BACKGROUND

[0002] 3D printing is a technology that uses powder-like metal, plastic, resin and other printing materials as the basis, and constructs objects through layer-by-layer printing. During printing, the printing materials are solidified by radiation energy.

[0003] In the process of 3D printing, the printing materials are located in a container, and the energy radiation device radiates energy towards the printing materials in the container to solidify them. Since the energy of the energy radiation device will attenuate with the projection distance, in order to ensure the accuracy of the solidification, it is necessary to keep the distance between the energy radiation device and the printing surface stable during printing to avoid over-solidification caused by too close distance or insufficient solidification caused by too far distance. SUMMARY

[0004] In view of the above-mentioned shortcomings of the related art, the purpose of the present application is to provide a liquid level adjusting method and system, and a 3D printing device and printing method applicable thereto, to overcome the above-mentioned technical problems existing in the related art.

[0005] To achieve the above-mentioned purposes and other related purposes, the first aspect of the present application provides a liquid level adjusting method for adjusting the liquid level height of photocurable materials in a container of a 3D printing device, the 3D printing device further comprising a carrying mechanism for carrying a 3D component during printing, the liquid level adjusting method comprising the following steps: determining a liquid level height adjusting value corresponding to at least one printing layer based on the volume change of the carrying mechanism immersed in the photocurable materials during the printing process of the at least one printing layer; and adjusting the liquid level height of the photocurable materials in the container based on the liquid level height adjusting value, and keeping the liquid level height within a reference liquid level height interval.

[0006] In some embodiments of the first aspect of the present application, further comprising: determining the current liquid level adjusting direction based on the liquid level height adjusting value and the difference between the current liquid level height and the upper limit or lower limit of the reference liquid level height interval.

[0007] In some embodiments of the first aspect of the present application, under the condition that the liquid level height is kept within the reference liquid level height interval, the current liquid level adjusting direction is the same as the previous liquid level adjusting direction.

[0008] In some embodiments of the first aspect of the present application, if the current liquid level height value is close to the upper limit or lower limit of the reference liquid level height interval, the liquid level height adjusting value is reduced.

[0009] In some embodiments of the first aspect of the present application, the method further comprises the step of detecting the liquid level of the photocurable material in the container after every predetermined number of layers.

[0010] In some embodiments of the first aspect of the present application, the method further comprises determining the liquid level adjustment value corresponding to the at least one printing layer based on the consumption of the photocurable material required for printing the at least one printing layer.

[0011] In some embodiments of the first aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by adjusting the height of the container.

[0012] In some embodiments of the first aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by adjusting the volume of the photocurable material that a balancing device sinks into.

[0013] In some embodiments of the first aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by delivering or extracting the photocurable material into or out of the container by a liquid supplementing device.

[0014] In some embodiments of the first aspect of the present application, the 3D printing device is a top projection 3D printing device.

[0015] In some embodiments of the first aspect of the present application, the reference liquid level interval is determined based on the height of a reference surface printed by the 3D printing device and an error boundary value.

[0016] The second aspect of the present application provides a liquid level adjustment system for adjusting the liquid level of a photocurable material in a container of a 3D printing device, the 3D printing device further comprising a carrying mechanism for carrying a 3D component during a printing job, the liquid level adjustment system comprising: a processing module configured to determine a liquid level adjustment value corresponding to at least one printing layer based on the change in the volume of the photocurable material that the carrying mechanism sinks into during the printing of the at least one printing layer; and an adjustment module configured to adjust the liquid level of the photocurable material in the container based on the liquid level adjustment value and to maintain the liquid level within a reference liquid level interval.

[0017] In some embodiments of the second aspect of the present application, the processing module is further configured to determine the current liquid level adjustment direction based on the liquid level adjustment value and the difference between the current liquid level and the upper or lower limit of the reference liquid level interval.

[0018] In some embodiments of the second aspect of the present application, the processing module is configured to cause the current liquid level adjustment direction to be the same as the previous liquid level adjustment direction when the condition that the liquid level is maintained within the reference liquid level interval is satisfied.

[0019] In some embodiments of the second aspect of the present application, the processing module decreases the liquid level adjustment value if the current liquid level value is close to the upper limit or the lower limit of the reference liquid level interval.

[0020] In some embodiments of the second aspect of the present application, further comprising a detecting module configured to detect the liquid level of the photocurable material in the container after every interval of a preset number of layers.

[0021] In some embodiments of the second aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by adjusting the height of the container.

[0022] In some embodiments of the second aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by adjusting the volume of the photocurable material that a balancing device sinks into.

[0023] In some embodiments of the second aspect of the present application, the liquid level adjustment of the photocurable material in the container is achieved by delivering or extracting photocurable material into or out of the container by a liquid supplementing device.

[0024] In some embodiments of the second aspect of the present application, the 3D printing device is a top projection 3D printing device.

[0025] In some embodiments of the second aspect of the present application, the reference liquid level interval is determined based on the height of a reference surface printed by the 3D printing device and an error boundary value.

[0026] In some embodiments of the second aspect of the present application, further comprising a storage module configured to store physical parameters of a carrying mechanism in the 3D printing device; and an interface module configured to obtain a movement amount of the carrying mechanism in the 3D printing device during printing of at least one printing layer, so that the processing module calculates a volume change of the carrying mechanism immersed in the photocurable material during printing of the at least one printing layer based on the movement amount.

[0027] In some embodiments of the second aspect of the present application, further comprising an interface module configured to obtain a volume change of the carrying mechanism immersed in the photocurable material during printing of at least one printing layer.

[0028] In some embodiments of the second aspect of the present application, the interface module is further configured to obtain slice images in a 3D component model, so that the processing module determines the liquid level adjustment value corresponding to the at least one printing layer based on a required consumption of the photocurable material during printing of the at least one slice image.

[0029] The third aspect of the present application provides a 3D printing method for a 3D printing device, the 3D printing device comprising an energy radiation device, a carrying mechanism, and a container for containing a light-curing material, the 3D printing method comprising: adjusting the height of the carrying mechanism to fill a printing material to be cured on a printing reference surface; causing the energy radiation device to irradiate a slice image in a 3D component model to the filled printing material to obtain a pattern-cured layer; repeating the above steps to accumulate the pattern-cured layers on the component platform, thereby forming a corresponding 3D component; wherein, during the printing process, the 3D printing device adjusts the liquid level height of the light-curing material in the container based on the liquid level adjusting method in any one of the embodiments of the first aspect of the present application.

[0030] In some embodiments of the third aspect of the present application, the 3D printing device is a top projection 3D printing device, and the 3D printing device further comprises a coating mechanism, and the step of causing the energy radiation device to irradiate a slice image in a 3D component model to the filled printing material to obtain a pattern-cured layer further comprises: causing the coating device to uniformly coat the light-curing material on the printing reference surface.

[0031] The fourth aspect of the present application provides a 3D printing device, comprising: a container for containing a material to be cured; an energy radiation device located above or below the container, for irradiating energy to the light-curing material in the container according to a slice image, so that the light-curing material is cured and formed; a carrying mechanism comprising a support arm and a component platform connected to the support arm, the support arm being located partially in the container during a printing operation, and the component platform being located in the container during the printing operation and being used to accumulate and attach pattern-cured layers layer by layer to form a corresponding 3D component; a Z-axis driving mechanism connected to the support arm, for adjusting the height of the component platform in the Z-axis direction, so as to adjust the distance between the component platform and the printing reference surface during the printing operation; and a control device connected to the energy radiation device and the Z-axis driving mechanism, for controlling the energy radiation device and the Z-axis driving mechanism during the printing operation, so as to accumulate and attach pattern-cured layers on the component platform based on the 3D printing method in any one of the embodiments of the third aspect of the present application to form a corresponding 3D component.

[0032] In some embodiments of the fourth aspect of the present application, the 3D printing device further comprises: a lifting mechanism connected to the control device and the container, for driving the container to move up and down under the control of the control device, so as to adjust the liquid level height of the light-curing material in the container by adjusting the height of the container.

[0033] In some embodiments of the fourth aspect of the present application, the 3D printing device further comprises a balancing device connected to the control device, and configured to move under the control of the control device to adjust the liquid level of the photocurable material in the container by adjusting the volume of the photocurable material immersed in the balancing device.

[0034] In some embodiments of the fourth aspect of the present application, the 3D printing device further comprises a liquid supplementing device connected to the control device and the container, and configured to deliver or extract photocurable material into or out of the container under the control of the control device to adjust the liquid level of the photocurable material in the container.

[0035] In some embodiments of the fourth aspect of the present application, the 3D printing device further comprises a detecting device located above the container and connected to the control device, and configured to detect the liquid level of the photocurable material in the container.

[0036] In some embodiments of the fourth aspect of the present application, the 3D printing device is a top projection 3D printing device, and the 3D printing device further comprises a coating mechanism arranged above the container and configured to uniformly coat the photocurable material on the printing reference surface during movement from one side of the container to the other side.

[0037] In summary, the liquid level adjusting method, system, 3D printing device and printing method provided by the present application do not directly rely on the detection data of the detecting device to adjust the liquid level, thereby avoiding errors caused by uneven liquid surface. The present application takes the volume change of the photocurable material immersed in the bearing mechanism as the main input and frequently adjusts the liquid level, so that the flow leveling time of the adjusted liquid surface is shorter, the liquid surface fluctuation is small, the printing efficiency and precision are improved, and the printing quality is improved.

[0038] Other aspects and advantages of the present application will be readily appreciated by those skilled in the art from the following detailed description, wherein only exemplary embodiments of the present application are shown and described. The present application is capable of modifications in various obvious respects, as will be readily apparent to those skilled in the art from the detailed description that follows. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. BRIEF DESCRIPTION OF DRAWINGS

[0039] The specific features of the present application are shown in the appended claims. The features and advantages of the present application can be better understood by reference to the following detailed description of exemplary embodiments and the accompanying drawings. A brief description of the drawings is as follows:

[0040] Figure 1 A simple structure schematic diagram of a top projection 3D printing device in an embodiment of the present application is shown.

[0041] Figure 2 A schematic diagram of a structure of a bearing mechanism in an embodiment of the present application is shown.

[0042] Figure 3 A schematic diagram of a structure of a liquid level adjusting system in an embodiment of the present application is shown.

[0043] Figure 4 A schematic diagram of a method of adjusting a liquid level in an embodiment of the present application is shown.

[0044] Figure 5 A schematic diagram of a curve of a liquid level change of a photocurable material in a container in an embodiment of the present application is shown.

[0045] Figure 6 A schematic diagram of a structure of a printing apparatus with a lifting mechanism in an embodiment of the present application is shown.

[0046] Figure 7 A schematic diagram of a structure of a printing apparatus with a balancing device in an embodiment of the present application is shown.

[0047] Figure 8 A schematic diagram of a structure of a printing apparatus with a liquid supplementing device in an embodiment of the present application is shown.

[0048] Figure 9 A schematic diagram of a 3D printing method in an embodiment of the present application is shown.

[0049] Figure 10 A schematic diagram of a 3D printing apparatus with a detecting device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0050] The implementation of the present application is described below by way of specific embodiments, and other advantages and effects of the present application can be easily understood by those skilled in the art from the contents disclosed in the specification.

[0051] In the following description, reference is made to the accompanying drawings, which form a part hereof, and in which several embodiments of the present application are shown by way of illustration. It is to be understood that other embodiments can be used and that structural or functional modifications can be made without departing from the spirit and scope of the present disclosure. The following detailed description is not to be interpreted in a limiting sense, and the scope of the embodiments of the present application is defined only by the appended patent claims. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application.

[0052] Moreover, as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of stated features, steps, operations, elements, components, items, and / or groups but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, items, and / or groups thereof. As used herein, the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or any combination of the items. Thus, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. Only when a combination of elements, functions, steps or acts is inherently mutually exclusive is an exception to this definition presented.

[0053] As described in the background section, the 3D printing device needs to keep the distance between the energy radiation device and the printing forming surface stable during the printing process. In the top exposure printing device, since the height of the energy radiation device is usually unchanged during the printing process, and when the energy radiation device is located above the container and radiates energy into the container, the printing material located at the top will be solidified and formed, so the distance between the energy radiation device and the printing forming surface can be adjusted by adjusting the liquid level height of the printing material in the container.

[0054] In some embodiments, after each layer is printed, the liquid level height in the container is detected by a liquid level detection mechanism, if the detected liquid level height exceeds a threshold value, the liquid level height is increased or decreased to make the liquid level height in the container within the desired range, if the detected liquid level height does not exceed the threshold value, the liquid level does not need to be adjusted, and the printing of the next layer continues. However, the present application finds that this liquid level adjustment method has several significant problems, first, after each adjustment of the liquid level, due to the flowability problem of the printing material, it is necessary to wait for the material to flow for a certain period of time. In addition, the liquid surface after each layer of printing can also be uneven, so that there is an error between the local liquid level value detected by the liquid level detection data and the actual liquid level value, and then the actual liquid level height after adjustment is not at the ideal position. And this adjustment method also makes the obvious change of the liquid level height before and after the adjustment of the liquid level cause the cross grain phenomenon of the printed part to be obvious.

[0055] In view of this, the present application provides a liquid level adjustment method for adjusting the liquid level height of the photocurable material in the container of the 3D printing device, which can be performed by a liquid level adjustment system.

[0056] It should be understood that 3D printing is a kind of rapid prototyping technology, which is a technology that uses powder-like metal or plastic and other cohesible printing materials to construct objects through layer-by-layer printing based on a digital model file. When printing, the digital model file is first processed to import the 3D component model to be printed into the 3D printing device. The physical object printed based on the 3D component model is the 3D component. Here, the 3D component model includes but is not limited to a 3D component model based on a CAD component, such as an STL file, and the control device performs layout and slicing processing on the imported STL file. The 3D component model can be imported into the control device through a data interface or a network interface. The solid part in the imported 3D component model can be of any shape, wherein the solid part is the part used to represent the structure of the 3D component, and the solid part can include tooth-shaped, spherical, house-shaped, tooth-shaped, or any shape with a preset structure, etc. Among them, the preset structure includes but is not limited to at least one of the following: a cavity structure, a structure containing a shape mutation, and a structure with a preset requirement for the contour accuracy of the solid part, etc.

[0057] In a light-curing 3D printing device, the printing material is usually a light-curing material. The 3D printing device prints the 3D component by layer-by-layer exposure and accumulation of each solidified layer of the light-curing material by the energy radiation device. The working principle of the specific light-curing rapid prototyping technology is as follows: using light-curing material as raw material, under the control of the control device, the energy radiation device irradiates each slice image according to the slice image for layer-by-layer exposure or scanning, and generates a photopolymerization reaction with the resin thin layer located in the irradiation area to solidify and form a thin layer section of the product. When a layer is solidified, the workbench moves a layer thickness, and a new layer of light-curing material is covered on the just solidified resin surface for cyclic exposure or scanning. The newly solidified layer is firmly bonded to the previous layer, and the process is repeated, layer by layer, to ultimately form the entire product prototype, i.e., the 3D component. The light-curing material generally refers to a material that forms a solidified layer after being irradiated by light (such as ultraviolet light, laser, etc.), which includes but is not limited to: photosensitive resin, or a mixture of photosensitive resin and other materials, etc. The other materials are, for example, ceramic powder, colorant, etc.

[0058] In the present application, the 3D printing device can be a top projection printing device or a bottom projection printing device. Since the printing forming surface of the top projection printing device is greatly affected by the liquid level, the effect of the liquid level adjusting system in the top projection printing device is more significant compared with the prior art. Of course, the liquid level adjusting method and the liquid level adjusting system in the present application are not exclusive to the bottom projection printing device, and can be theoretically applied to the bottom projection printing device. In some embodiments, the top projection can also be referred to as top exposure, top projection exposure, or upper projection; the bottom projection can also be referred to as bottom exposure, bottom projection exposure, or lower projection. In the top projection printing device, the energy radiation device is located above the container, and the energy radiation device radiates energy to the container below, i.e., downward projection; in the top exposure-based printing device, the Z-axis driving mechanism is used to move the component platform in the Z-axis direction to adjust the position of the component platform to form a printing reference surface between the upper surface of the component platform and the liquid surface of the printing material in the container. In the bottom projection printing device, the energy radiation device is located below the container, and the energy radiation device radiates energy to the bottom surface of the container above, i.e., upward projection.

[0059] Please refer to Figure 1 which shows a simple structure schematic diagram of the top projection 3D printing device in an embodiment of the present application. As shown in the figure, the 3D printing device comprises an energy radiation device 11, a container 12, a bearing mechanism 13, a Z-axis driving system 14, and a control device 15.

[0060] The container 12 is used to hold the printing material to be solidified, and in the light-curing printing device, the printing material is a light-curing material. The light-curing material includes any liquid or powder material that is easy to be light-cured, and the liquid material includes, for example, a light-curing resin liquid or a resin liquid mixed with ceramic powder, color additives, etc. The material of the container includes, but is not limited to, glass, plastic, resin, etc. The capacity of the container depends on the type of the 3D printing device or the overall size of the energy radiation device in the 3D printing device. In some cases, the container can also be referred to as a resin tank. The container can be entirely transparent or only the bottom of the container is transparent, for example, the container is a glass container, and the container wall is attached with light-absorbing paper (such as black film or black paper, etc.) to reduce the interference of light scattering with the curing of the light-curing material during projection. In some embodiments, for the printing device based on bottom exposure forming, a transparent flexible film (not shown) for facilitating the separation of the printed solidified layer from the container bottom surface is also laid on the inside bottom surface of the container, and the transparent flexible film for facilitating the separation is, for example, a FEP release film, which is a hot melt extrusion casting film made of ultra-high purity FEP resin (fluorinated ethylene propylene copolymer). The FEP release film has excellent non-stickiness, high temperature resistance, electrical insulation, mechanical properties, wear resistance, etc.

[0061] The carrier mechanism is used to carry the 3D component printed by the printing device, and is controlled to move by the Z-axis driving mechanism. Please refer to Figure 2 , which shows the structure of the carrier mechanism in an embodiment of the present application. As shown in the figure, the carrier mechanism 13 includes a support arm 132 and a component platform 131 connected to the support arm, the support arm 132 is partially located in the container during the printing operation, and the support arm is connected to the Z-axis driving mechanism so as to be controlled to move by the Z-axis driving mechanism. The component platform is located in the container during the printing operation and is used to accumulate the solidified layers of the attached pattern layer by layer to form the corresponding 3D component, and in some embodiments, the component platform is also referred to as a component plate. During the printing process, especially in the top exposure printing device, due to the layer-by-layer accumulation of the solidified layers of the pattern, the component platform is usually lowered layer by layer,

[0062] The Z-axis driving mechanism is connected to the support arm and is used to adjust the height of the component platform in the Z-axis direction to adjust the distance between the component platform and the printing reference surface during the printing operation. In some embodiments, the position of the printing reference surface is determined based on the type of the printing device. For example, when the printing device is a top exposure printing device, the component platform is lowered below the liquid surface in an embodiment, so that the upper surface of the component platform and the liquid level surface of the printing material serve as the printing reference surface; for another example, when the printing device is a bottom exposure printing device, the component platform is lowered to a position close to the bottom of the container in an embodiment, so that the lower surface of the component platform and the inner surface of the bottom of the container serve as the printing reference surface.

[0063] Please continue to refer to Figure 1 , the Z-axis driving system 14 can move in the Z-axis direction to drive the carrier mechanism 13 to rise or fall during the printing operation, and the Z-axis driving system includes a Z-axis component and a driving device for driving the Z-axis component to move up and down. The component platform is usually located in the container during the printing operation and is connected to the Z-axis component through the support arm, and is used to adjust the distance between the component platform and the printing reference surface during the printing operation and to accumulate the solidified layers of the attached pattern layer by layer to form the 3D component.

[0064] The Z-axis driving mechanism comprises a driving unit and a Z-axis moving unit, the driving unit is used to drive the Z-axis moving, so that the Z-axis moving unit drives the component platform to move axially along the Z-axis, for example, the driving unit can be a driving motor. The driving unit is controlled by a control instruction. The control instruction comprises a directional instruction for indicating the component platform to ascend, descend or stop, and can further comprise parameters such as rotating speed / rotating speed acceleration, or torque / torsion, etc. Thus, the distance of the Z-axis moving unit ascending can be accurately controlled, so as to realize the accurate adjustment of the Z-axis. Herein, the Z-axis moving unit comprises a fixed rod fixed at one end of the component platform, and a clamping moving assembly fixed at the other end of the fixed rod, wherein the clamping moving assembly is driven by the driving unit to drive the fixed rod to move axially along the Z-axis, and the clamping moving assembly is for example a limiting moving assembly clamped by a toothed structure, such as a rack, etc. For another example, the Z-axis moving unit comprises a lead screw and a positioning moving structure screwed with the lead screw, wherein the two ends of the lead screw are screwed with the driving unit, and the extension end of the positioning moving structure is fixedly connected to the component platform, and the positioning moving structure can be for example a ball screw. The component platform is a part for attaching and carrying the formed solidified layer. The component platform is used to attach and carry the formed cross section layer, and the cross section layer on the component platform is accumulated layer by layer to form a 3D component.

[0065] The energy radiation device is used to project an image to the direction of the component platform, and in the printing operation, the energy radiated by the energy radiation device can make the photocuring material on the printing reference surface to be shaped. The control device is connected with the energy radiation device and the Z-axis driving system, and is used to control the energy radiation device and the Z-axis driving system in the printing operation, so as to accumulate and attach the solidified layer on the component platform to obtain a corresponding 3D component.

[0066] The type of the energy radiation device can be determined based on the type of the 3D printing equipment.

[0067] In an embodiment, the 3D printing device is a SLA (Stereo lithography Apparatus) printing device, and the energy radiation system of the 3D printing device comprises a laser emitter, a lens group located on the light path of the laser emitter, a galvanometer group located on the light exit side of the lens group, and a motor for controlling the galvanometer, etc. The laser emitter is controlled to adjust the energy of the laser beam, for example, the laser emitter is controlled to emit a laser beam with a preset power and stop emitting the laser beam, or the laser emitter is controlled to increase the power of the laser beam and decrease the power of the laser beam. The lens group is used to adjust the focusing position of the laser beam, and the galvanometer group is used to control the scanning of the laser beam in the two-dimensional space on the bottom surface or the top surface of the container. The photocurable material scanned by the laser beam is cured into a corresponding patterned cured layer, and the swing amplitude of the galvanometer of the galvanometer group determines the scanning size of the SLA device.

[0068] In another embodiment, the 3D printing device is a DLP (Digital Light Procession) printing device. In the DLP device, the energy radiation system comprises a DMD chip, a controller, and a storage module. The storage module stores the layer images of the 3D component model. The DMD chip irradiates the light source corresponding to each pixel of the layer image to the top surface of the container after receiving the control signal of the controller. The DMD chip appears to be a small mirror from the outside, and is encapsulated in a sealed space composed of metal and glass. In fact, the mirror is composed of hundreds of thousands or even millions of micro-mirrors, each micro-mirror represents a pixel, and the projected image is composed of these pixels. The DMD chip can be simply described as a semiconductor light switch and a micro-mirror corresponding to a pixel point. The controller controls each light switch in the DMD chip to allow / inhibit each micro-crystal to reflect light, thereby irradiating the corresponding layer image to the photocurable material through the transparent top of the container, so that the photocurable material corresponding to the image shape is cured to obtain a patterned cured layer.

[0069] In yet another embodiment, the 3D printing device is an LCD printing device. Taking a liquid crystal face light source curing LCD as an example, in the LCD printing device, the energy radiation device includes an LCD liquid crystal screen located above the container and a light source arranged in alignment above the LCD liquid crystal screen. The control chip in the energy radiation device projects the layered image of the to-be-printed slice onto the printing surface through the LCD liquid crystal screen, and uses the pattern radiation surface provided by the LCD liquid crystal screen to cure the to-be-cured material in the container into a corresponding pattern cured layer. The light source includes, but is not limited to, a 406 nm UV-LED light source, a 355 nm UV-LED light source, visible light, etc., which can be determined according to the specific needs of the printing material in specific applications. For example, visible light can be used as the radiation source for the printing material of visible light curing irradiation forming, and for example, the corresponding waveband ultraviolet light can be used as the radiation source for the printing material of waveband ultraviolet light irradiation forming.

[0070] The control device 15 is an electronic device including a processor, which can be a computer device, an embedded device, an integrated circuit integrated with a CPU, or the like. For example, the control device can include a processing unit, a storage unit, and a plurality of interface units. Each interface unit is connected to a device in the 3D printing device, such as the energy radiation device and the Z-axis driving mechanism, which is independently packaged and transmits data through an interface. The control device further includes at least one of a prompting device, a human-computer interaction device, or the like. The interface unit determines its interface type according to the connected device, which includes but is not limited to a universal serial bus (USB) interface, a high-definition multimedia interface (HDMI) interface, an industrial control interface, or the like. For example, the interface unit includes a USB interface, an HDMI interface, and an RS232 interface, of which the USB interface and the RS232 interface are both multiple. The USB interface can be connected to a human-computer interaction device or the like. The storage unit is used to store files required for printing by the 3D printing device. The files include program files and configuration files required for running of the CPU, or the like. The storage unit includes a non-volatile memory and a system bus. The non-volatile memory is exemplified by a solid state disk or a U disk, or the like. The system bus is used to connect the non-volatile memory and the CPU together, of which the CPU can be integrated in the storage unit, or packaged separately from the storage unit and connected to the non-volatile memory through the system bus. The processing unit includes at least one of a CPU, a chip integrated with the CPU, a field programmable gate array (FPGA), and a multi-core processor. The processing unit further includes a memory, a register, and other memories for temporarily storing data. The processing unit becomes an industrial control unit for controlling the devices to execute in time sequence. For example, during the printing process, after the processing unit controls the Z-axis driving mechanism to move the component platform to a position with a distance from a preset printing reference surface, the processing unit controls the energy radiation device to radiate energy to the material to be solidified on the printing reference surface according to a layer image, and after the energy radiation device completes the irradiation to patternize and solidify the photopolymerization material, the Z-axis driving mechanism drives the component platform to adjust and move to a new position with a distance from the preset printing reference surface, and the above exposure process is repeated.

[0071] In one exemplary embodiment, please refer to Figure 3 which shows a structural schematic diagram of the liquid level adjusting system in an embodiment of the present application. As shown in the figure, the liquid level adjusting system 20 includes a processing module 201 and an adjusting module 202.

[0072] The interface module 201 determines its interface type according to the connected device, which includes but is not limited to: universal serial interface, video interface, industrial control interface, etc. For example, the interface module 201 can include USB interface, HDMI interface, RS232 interface, etc. The interface module can be connected to the liquid level adjusting device for the liquid level in the 3D printing equipment, so that the corresponding control signal can be sent to the liquid level adjusting device based on the processing result of the processing module, so that the energy radiation device irradiates the layered image in the 3D component model to the filled printing material to obtain a pattern solidification layer. The processing module 202 includes at least one of CPU or chip integrated with CPU, programmable logic device (FPGA), and multi-core processor. The processing module 202 also includes memory, registers, and other storage devices for temporarily storing data.

[0073] In an exemplary embodiment, please refer to Figure 4 which shows the schematic diagram of the liquid level adjusting method in an embodiment of the present application.

[0074] As shown in the figure, in step S110, the liquid level height adjusting value corresponding to at least one printing layer is determined according to the volume change of the carrying mechanism immersed in the photocurable material during the printing process of the at least one printing layer. Here, the corresponding liquid level height adjusting value can be determined for each printing layer, or the corresponding liquid level height adjusting value can be determined for multiple printing layers, such as 5 layers, 10 layers, 15 layers, 20 layers, 25 layers, 30 layers, etc.

[0075] In some embodiments, in order to make the surface precision of the printed 3D component higher, the liquid level height adjusting value can be determined respectively after each printing layer is printed. In other embodiments, for example, in the case that the adjusting precision of the liquid level adjusting device is not enough, in order to balance the adjusting precision of the liquid level adjusting device and the surface precision of the printed component, the corresponding liquid level height adjusting value can be determined after multiple printing layers are printed, such as: every 2 printing layers, every 3 printing layers, every 4 printing layers, every 5 printing layers, every 6 printing layers, every 7 printing layers, every 8 printing layers, every 9 printing layers, every 10 printing layers, every 11 printing layers, every 12 printing layers, every 13 printing layers, every 14 printing layers, every 15 printing layers, etc.

[0076] Since the component platform needs to be adjusted frequently in height during the printing process, the support arm driving the component platform to rise and fall is also frequently adjusted in height during the printing process, so it can be understood that the volume of the carrying mechanism immersed in the photocurable material in the container also changes during the entire printing process, thereby causing the change of the liquid level of the photocurable material in the container. In some embodiments, the height of one printing layer needs to be adjusted after each printing layer is printed, so the liquid level changes due to the volume change of the carrying mechanism immersed in the photocurable material after each layer is printed.

[0077] For the convenience of description, each printing layer that needs to adjust the liquid level height is referred to as a liquid level height adjustment layer. Based on the above description, each printing layer can be a liquid level height adjustment layer, or multiple printing layers can be a liquid level height adjustment layer.

[0078] In some embodiments, the liquid level height adjustment values corresponding to each liquid level height adjustment layer are the same, for example, in the case where the moving height of the component platform after printing each printing layer is the same. In other embodiments, the liquid level height adjustment values corresponding to each liquid level height adjustment layer can also be different, for example, in the printing of some 3D components, the printing layer thickness of parts with high precision requirements is smaller, and the printing layer thickness of parts with low precision requirements is larger. At this time, since the height of the component platform needs to be moved is different, the volume of the bearing mechanism immersed in the photocurable material is also different, that is, the liquid level height adjustment values corresponding to each liquid level height adjustment layer are also different.

[0079] In possible implementations, each liquid level height adjustment layer and the corresponding liquid level height adjustment value can be determined before the 3D printing device performs a printing task. For example, after the liquid level adjustment system knows the physical size of the bearing mechanism and the component platform moving amount corresponding to each printing layer, it can calculate the volume change of the bearing mechanism immersed in the photocurable material based on the component platform moving amount corresponding to at least one printing layer and the physical size of the bearing mechanism, and obtain the liquid level height adjustment value. In other possible implementations, the volume change of the bearing mechanism immersed in the photocurable material can also be calculated based on the component platform moving amount corresponding to at least one printing layer and the physical size of the bearing mechanism after the printing task of the at least one printing layer is completed, and the liquid level height adjustment value is obtained.

[0080] Please continue to refer to Figure 4 In step S120, the liquid level height of the photocurable material in the container is adjusted based on the liquid level height adjustment value, and the liquid level height is maintained within the reference liquid level height interval.

[0081] Here, since the energy of the energy radiation device will attenuate with the projection distance, in order to ensure the accuracy of the molding, it is necessary to keep the distance between the energy radiation device and the printing molding surface basically stable during the printing process, so as to avoid over-curing caused by too close distance, or insufficient curing caused by too far distance. Therefore, during the process of adjusting the liquid level height, it is necessary to maintain the liquid level height within the reference liquid level height interval. The reference liquid level height interval represents the defined liquid level height range for the printing component to have better molding quality.

[0082] In possible implementations, the reference liquid level height interval is determined based on a printing reference surface. The printing reference surface represents the ideal position of the printing molding surface.

[0083] It is to be noted that the printing forming surface refers to the liquid surface of the light-cured material forming, for example, the liquid level surface of the light-cured material in the up-projection printing device, and the printing forming surface changes with the change of the liquid level. The printing reference surface generally refers to the most ideal forming height, which is mainly determined by the energy intensity of the energy radiation device and / or the properties of the printing material, and thus in the process of 3D printing, the printing forming surface needs to be close to the printing reference surface to ensure that the position of the light-cured material being cured is at the most ideal forming position, so as to ensure that the energy received by the light-cured material is within the ideal range.

[0084] Although better printing quality can be achieved when the printing forming surface is just at the printing reference surface, in some embodiments, if only the printing forming surface is allowed to be just at the printing reference surface or only allowed to be at a distance very close to the printing reference surface (for example, about 0.02 mm), it is easy to cause large fluctuations in the liquid level when adjusting the liquid level, forming horizontal lines, and thus in an exemplary embodiment, a threshold range can be set to allow the height of the printing forming surface to float within a certain range above and below the printing reference surface, which enables to meet certain printing quality while improving printing efficiency.

[0085] Therefore, in the process of adjusting the liquid level by the liquid level adjusting system, the liquid level of the light-cured material in the container is kept within the reference liquid level height interval. The reference liquid level height interval represents the ideal printing liquid level height range, so that the printing forming surface during printing is as close to the printing reference surface as possible.

[0086] In possible embodiments, the reference liquid level height interval can be determined based on the height of the printing reference surface and the error boundary value. The height of the printing reference surface and the error boundary value can be determined based on different performances of the 3D printing device, i.e., the printing reference surface includes the most ideal forming height in the 3D printing device, and the error boundary value includes the deviation value relative to the printing reference surface that can be allowed on the basis of meeting the minimum printing quality requirement. In an example, the error boundary value includes, but is not limited to, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc. Assuming that the height of the printing reference surface is h and the error boundary value is x, the lower limit of the reference liquid level height interval is h-x and the upper limit is h+x.

[0087] In an exemplary embodiment, after the liquid level height adjusting value is determined based on step S110, the liquid level height is controlled within the reference liquid level height interval as the target to adjust the liquid level height of the light-cured material in the container.

[0088] It can be understood that the liquid level adjustment includes two directions, i.e. adjusting the liquid level up or adjusting the liquid level down. Taking a top projection printing device as an example, during the 3D printing process, the carrying mechanism gradually immerses more into the photocurable material during the downward movement, resulting in the liquid level rising, at this time the liquid level needs to be adjusted down to balance the change of the liquid level caused by the descent of the carrying mechanism. However, due to the difficulty in accurately regulating the liquid level, in some embodiments, due to the limited adjustment accuracy of the liquid level control device, it is difficult to accurately calculate the height change of the liquid level after printing of at least one printing layer, and to accurately compensate for the change, so during the liquid level adjustment, even if the liquid level height adjustment value is determined based on the volume change of the carrying mechanism immersed in the photocurable material, when the liquid level is adjusted in the same adjustment direction based on the liquid level height adjustment value, the liquid level will not usually stabilize at a certain value or within a certain range, for example, the liquid level may change linearly. The linear change of the liquid level will cause the liquid level to exceed the upper limit or lower limit of the reference liquid level height interval, so the direction of the liquid level adjustment needs to be changed in time.

[0089] Based on such understanding, in an exemplary embodiment, the processing module further determines the current liquid level adjustment direction based on the liquid level height adjustment value and the difference between the current liquid level height and the upper limit or lower limit of the reference liquid level height interval.

[0090] Here, in order to keep the liquid level height within the reference liquid level height interval, the liquid level position in the container can be determined by predicting the liquid level, for example, predicting the liquid level height after the liquid level adjustment according to the liquid level change during the printing process combined with the liquid level height adjustment value, and changing the liquid level adjustment direction when the liquid level height is about to exceed the reference liquid level height interval.

[0091] In other embodiments, the liquid level position in the container can also be detected every layer or every few layers, for this purpose, the liquid level adjustment system further comprises a detection module, which can be connected with the interface module to send detection data to the interface module and provide the detection data to the processing module for processing, the detection module includes but is not limited to a liquid level sensor and the like. When the detection module detects that the liquid level position exceeds or is about to exceed the upper limit or lower limit of the reference liquid level height interval, the liquid level adjustment direction can be changed. Therefore, in some embodiments, the liquid level adjustment method further comprises the step of detecting the liquid level height of the photocurable material in the container every interval of a preset number of layers. The preset number of layers can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, 10 layers, 11 layers, 12 layers, 13 layers, 14 layers, 15 layers, 16 layers, 17 layers, 18 layers, 19 layers, 20 layers, etc., which can be configured according to actual needs so that the liquid level can be detected in time when it is about to exceed the reference liquid level height interval.

[0092] In some embodiments, before adjusting the liquid level at each liquid level adjusting layer or every several liquid level adjusting layers, the liquid level in the container is detected. If the liquid level is close to the upper limit or the lower limit of the reference liquid level interval, or will exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjusting value, the liquid level adjusting direction is opposite to the previous liquid level adjusting direction. Otherwise, if the liquid level is not close to the upper limit or the lower limit of the reference liquid level interval, or will not exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjusting value, the liquid level adjusting direction is the same as the previous liquid level adjusting direction.

[0093] By the adjusting method in the above embodiments, the liquid level change of the photocurable material in the container is smooth. Please refer to Figure 5 which shows the liquid level change curve of the photocurable material in the container in an embodiment. As shown in the figure, after adjusting the liquid level by the liquid level adjusting method in the above embodiments, the fluctuation of the liquid level presents a relatively smooth broken line rule, thereby reducing the liquid surface flow time and significantly improving the printing quality.

[0094] In an exemplary embodiment, if the current liquid level value is close to the upper limit or the lower limit of the reference liquid level interval, the liquid level adjusting value is reduced, thereby making the liquid level change more stable and reducing the obvious fluctuation of the liquid level caused by the change of the liquid level adjusting direction. Even when the liquid level change curve changes the liquid level adjusting direction, it still presents a smooth curve similar to a sine wave.

[0095] Here, the close can be determined according to actual needs, which includes but is not limited to when the difference between the liquid level and the upper limit or the lower limit of the reference liquid level interval reaches 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% of the error boundary value. For example, taking the case where the difference between the liquid level and the upper limit or the lower limit of the reference liquid level interval reaches 80% of the error boundary value as an example, assuming that the height of the printing reference surface is h and the error boundary value is x, the lower limit of the reference liquid level interval is h-x and the upper limit is h+x, and the current liquid level is y, when the difference between y and h-x reaches 0.8x or the difference between y and h+x reaches 0.8x, the liquid level adjusting value is reduced. It should be understood that the above description of close is only for explanation and not limitation, and in actual application, the liquid level adjusting value can be reduced in what case to improve the printing quality according to the actual liquid level adjusting situation.

[0096] The specific amount of reduction can also be configured according to actual needs, for example, the liquid level adjustment value can be reduced by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, etc.

[0097] In an exemplary embodiment, since there is also consumption of the photocurable material after the printing material is solidified into a pattern solidification layer during printing, in some embodiments, the liquid level adjustment system also determines the liquid level adjustment value corresponding to the at least one print layer based on the consumption of the photocurable material required when printing the at least one slice image. That is, the volume in which the carrying mechanism is immersed in the photocurable material when printing the at least one slice image and the consumption of the photocurable material required when printing the at least one slice image are both used to determine the liquid level adjustment value, so that the adjustment accuracy is higher.

[0098] In an exemplary embodiment, the liquid level adjustment in the container can be achieved by a liquid level adjustment device.

[0099] In an embodiment, the liquid level height adjustment of the photocurable material in the container is achieved by adjusting the height of the container. It can be understood that the purpose of adjusting the liquid level height is to make the distance from the forming surface to the energy radiation device within a desired range, so that the printing quality is higher. In a top projection printing device, the forming surface is usually located at the uppermost part of the liquid surface, so by adjusting the height of the container, the distance between the liquid surface and the energy radiation device can also be adjusted, thereby achieving the adjustment of the liquid level. Of course, the adjusted liquid level height in this embodiment does not refer to the height of the liquid surface in the container relative to the bottom surface of the container, because only changing the height of the container will not affect the height of the liquid surface in the container relative to the bottom surface of the container, so it can be understood that the changed liquid level height in this embodiment refers to the height of the liquid surface in the container relative to the horizontal plane on which the printing device is located.

[0100] In possible embodiments, please refer toFigure 6 which shows the structure of the printing device with the lifting mechanism in an embodiment of the present application. As shown in the figure, a lifting mechanism 16 can be provided at the bottom of the container 12, so that the lifting mechanism drives the container to rise or fall. The lifting mechanism can be a screw rod transmission lifting mechanism, or a "liquid level adjusting system" as described in the application number CN2020227710185, which includes a lifting mechanism and a driving mechanism. The lifting mechanism is arranged at the bottom of the container and is used to drive the container to move up and down. The driving mechanism is connected to the lifting mechanism and is used to drive the lifting mechanism to adjust the liquid level position of the material to be formed in the container when receiving a control instruction. The lifting mechanism converts the driving force from the driving mechanism in a direction different from the lifting direction into a driving force in the lifting direction. The "liquid level adjusting system" described in the application corresponds to the liquid level adjusting device in the present application. Alternatively, the lifting mechanism can also use other structures in the prior art to realize the lifting of the container. Since the structure for driving the container to lift is not the point of the present application, it will not be described here. In some embodiments, the lifting mechanism can be connected to the liquid level adjusting system, so as to be controlled by the liquid level adjusting system to realize the lifting of the container. In other embodiments, the lifting mechanism can also be connected to the control device of the 3D printing device, so as to be driven by the control device to realize the lifting movement of the container.

[0101] In another embodiment, the liquid level height of the photocurable material in the container is adjusted by adjusting the volume of the balancing device immersed in the photocurable material. The balancing device includes, but is not limited to, the balancing block in the 3D printing device, that is, the volume of the balancing block immersed in the photocurable material in the container is used to control the liquid level in the container. It should be understood that the balancing block in 3D printing is a structure that can move up and down in the container, which is usually a regular cuboid or cubic structure, so as to facilitate the calculation of the change brought by the liquid level when descending. The volume of the balancing block is usually determined based on the size of the container.

[0102] In possible embodiments, please refer to Figure 7 which shows the structure of the printing device with the balancing device in an embodiment of the present application. As shown in the figure, the balancing device 17 can be partially or completely immersed in the photocurable material in the container 12 during printing. The balancing device can be connected to the liquid level adjusting system, so as to be controlled by the liquid level adjusting system to realize the lifting and control the liquid level by the volume immersed in the photocurable material. In other embodiments, the lifting mechanism can also be connected to the control device of the 3D printing device, so as to be controlled by the control device to realize the lifting.

[0103] In another embodiment, the liquid level adjustment of the photocurable material in the container is achieved by delivering or extracting photocurable material into or out of the container by a replenishment device. In this case, when it is necessary to raise the liquid level in the container, the photocurable material can be delivered into the container, and when it is necessary to lower the liquid level in the container, the photocurable material can be extracted out of the container.

[0104] In a possible implementation, the replenishment device can be connected to the liquid level adjustment system so as to be controlled by the liquid level adjustment system to deliver or extract the photocurable material. In other implementations, the lifting mechanism can also be connected to the control device of the 3D printing apparatus so as to be controlled by the control device to deliver or extract the photocurable material to achieve the liquid level adjustment of the photocurable material in the container. Please refer to Figure 8 In an embodiment, the replenishment device includes a delivery pipeline and a delivery pump 18 arranged on the pipeline to provide negative pressure or positive pressure, and the two ends of the delivery pipeline are respectively connected to the container 12 and a storage device 19 of the photocurable material, such as a resin barrel or other container for storing the photocurable material. The storage device is usually sealed in a non-use state to avoid the performance of the internal photocurable material being affected by long-term exposure to air. In some cases, a filtering mechanism can also be arranged on the delivery pipeline to avoid impurities in the container being brought into the storage device of the photocurable material when the photocurable material is extracted from the container of the 3D printing apparatus.

[0105] In an exemplary embodiment, the change of the volume of the photocurable material in which the carrying mechanism is immersed during the movement of each layer causes the change of the liquid level, and therefore, the change of the liquid level can be calculated according to the movement amount of the carrying mechanism and the physical parameters of the carrying mechanism when the physical parameters of the carrying mechanism are known. In this case, the liquid level adjustment system can further include a storage module for storing the physical parameters of the carrying mechanism in the 3D printing apparatus, including but not limited to the bottom area and thickness of the component platform in the carrying mechanism, the size of the supporting arm, etc. The interface module is used to obtain the movement amount of the carrying mechanism during the printing of at least one printing layer, so that the processing module calculates the change of the volume of the photocurable material in which the carrying mechanism is immersed during the printing of at least one printing layer according to the movement amount, and thus obtains the liquid level adjustment amount.

[0106] In some embodiments, the interface module of the liquid level adjustment system can be connected to the control device of the 3D printing apparatus to obtain the movement of the support mechanism during the printing of at least one printing layer. Alternatively, in some embodiments where the movement of the support mechanism during the printing of each printing layer is fixed, the interface module can obtain the movement only once instead of obtaining the movement for each printing layer. Further, the liquid level adjustment system can also have an external input module, such as a keyboard. The external input module is connected to the interface module, and the operator can input the movement of the support mechanism during the printing of at least one printing layer via the external input module. The interface module then provides the movement to the processing module so that the processing module can call the physical parameters of the support mechanism from the storage module and calculate the liquid level adjustment based on the movement.

[0107] In some embodiments, the change in the volume of the support mechanism immersed in the photocurable material during the printing of at least one printing layer can also be obtained externally. For example, the liquid level adjustment system can be connected to the control device of the 3D printing apparatus, and the control device can calculate the change in the liquid level based on the movement of the support mechanism and the physical parameters of the support mechanism and provide the change to the liquid level adjustment system. In this case, the control device of the 3D printing apparatus can have a storage module storing the physical parameters of the support mechanism, including but not limited to the bottom surface area of the build platform, the thickness of the build platform, the size of the support arm, etc. The interface module is used to obtain the movement of the support mechanism during the printing of at least one printing layer so that the processing module can calculate the change in the volume of the support mechanism immersed in the photocurable material during the printing of at least one printing layer based on the movement, and thus obtain the liquid level adjustment.

[0108] In some embodiments, the liquid level adjustment method can also be performed by the 3D printing apparatus instead of relying on a separate liquid level adjustment system.

[0109] Based on the above understanding, the liquid level adjustment method of the above embodiments can also be performed by the 3D printing apparatus.

[0110] In some embodiments, the 3D printing apparatus can determine the corresponding liquid level height adjustment value for at least one printing layer based on the change in the volume of the support mechanism immersed in the photocurable material during the printing of at least one printing layer. In this case, the corresponding liquid level height adjustment value can be determined for each printing layer, or the corresponding liquid level height adjustment value can be determined for a plurality of printing layers, such as 5 layers, 10 layers, 15 layers, 20 layers, 25 layers, 30 layers, etc.

[0111] In some embodiments, in order to make the surface of the printed 3D component more accurate, the liquid level adjustment value can be determined after each printing layer is printed. In other embodiments, for example, when the adjustment accuracy of the liquid level adjustment device is not enough, in order to balance the adjustment accuracy of the liquid level adjustment device and the surface accuracy of the printed component, the corresponding liquid level adjustment value can also be determined after multiple printing layers are printed, for example, every 2 printing layers, every 3 printing layers, every 4 printing layers, every 5 printing layers, every 6 printing layers, every 7 printing layers, every 8 printing layers, every 9 printing layers, every 10 printing layers, every 11 printing layers, every 12 printing layers, every 13 printing layers, every 14 printing layers, every 15 printing layers, etc.

[0112] Since the component platform needs to be adjusted frequently during printing, the support arm driving the component platform to rise and fall also needs to be adjusted frequently during printing. It can be understood that the volume of the support mechanism immersed in the container of the photocurable material also changes during the entire printing process, thereby causing the change of the liquid level of the photocurable material in the container. In some embodiments, the height of each printing layer needs to be adjusted after each printing layer is printed, so the liquid level changes due to the change of the volume of the support mechanism immersed in the photocurable material after each layer is printed.

[0113] For convenience of description, each printing layer that needs to adjust the liquid level height is referred to as a liquid level height adjustment layer. Based on the above description, each printing layer can be a liquid level height adjustment layer, or multiple printing layers can be a liquid level height adjustment layer.

[0114] In some embodiments, the liquid level height adjustment values corresponding to each liquid level height adjustment layer are the same, for example, when the moving height of the component platform after each printing layer is printed is the same. In other embodiments, the liquid level height adjustment values corresponding to each liquid level height adjustment layer can also be different, for example, in the printing of some 3D components, the printing layer thickness of the part with high accuracy requirement is smaller, and the printing layer thickness of the part with low accuracy requirement is larger. At this time, since the height of the component platform needs to be moved is different, the volume of the support mechanism immersed in the photocurable material is also different, that is, the liquid level height adjustment values corresponding to each liquid level height adjustment layer are different.

[0115] In possible embodiments, the liquid level adjustment layers and the corresponding liquid level adjustment values can be determined before the 3D printing device performs a printing task. For example, the 3D printing device can know the physical size of the bearing mechanism and the corresponding movement amount of the build platform for each printing layer, and then calculate the volume change of the bearing mechanism immersed in the photocurable material based on the movement amount of the build platform for at least one printing layer and the physical size of the bearing mechanism, and obtain the liquid level adjustment value; during printing, the liquid level can be adjusted at each liquid level adjustment layer based on the pre-calculated liquid level adjustment value. In other possible embodiments, the liquid level adjustment value corresponding to at least one printing layer can also be calculated after the printing task of the at least one printing layer is completed, for example, the volume change of the bearing mechanism immersed in the photocurable material is calculated based on the movement amount of the build platform corresponding to the at least one printing layer and the physical size of the bearing mechanism, and the liquid level adjustment value is obtained.

[0116] In one exemplary embodiment, the liquid level height of the photocurable material in the container is adjusted based on the liquid level adjustment value, and the liquid level height is maintained within a reference liquid level height interval.

[0117] Here, since the energy of the energy radiation device will attenuate with the projection distance, in order to ensure the accuracy of the molding, it is necessary to keep the distance between the energy radiation device and the printing molding surface stable during the printing process, so as to avoid over-curing caused by too close distance, or insufficient curing caused by too far distance, therefore, during the process of adjusting the liquid level height, it is necessary to maintain the liquid level height within the reference liquid level height interval. The reference liquid level height interval represents the defined range of liquid level height for the printing component to have better molding quality.

[0118] In possible embodiments, the reference liquid level height interval is determined based on a printing reference surface. The printing reference surface represents the ideal printing molding surface position.

[0119] It needs to be clarified here that the printing molding surface refers to the liquid surface of the photocurable material molding, for example, the liquid level surface of the photocurable material in the upper projection printing device, and the printing molding surface will change with the change of the liquid level. The printing reference surface usually refers to the most ideal molding height, which is mainly determined by the energy intensity of the energy radiation device and / or the properties of the printing material, therefore, during the 3D printing process, it is necessary to keep the printing molding surface close to the printing reference surface to ensure that the position of the photocurable material being cured is located at the most ideal molding position, so as to ensure that the energy received by the photocurable material is within the ideal range.

[0120] Although better printing quality can be achieved when the printing forming surface is just at the printing reference surface, in some embodiments, if only the printing forming surface is allowed to be just at the printing reference surface, or only allowed to be at a distance very close to the printing reference surface (e.g. around 0.01mm, 0.02mm, etc.), it can easily cause large fluctuations in the liquid level when adjusting the liquid level, forming horizontal lines, and thus in an exemplary embodiment, a threshold range can be set so as to allow the height of the printing forming surface to float within a certain range above and below the printing reference surface, which allows certain printing quality to be met while improving printing efficiency.

[0121] Thus, in the process of adjusting the liquid level of the 3D printing device, the liquid level of the photocurable material in the container is kept within the reference liquid level height interval. The reference liquid level height interval represents the ideal printing liquid level height range, so as to make the printing forming surface during printing as close to the printing reference surface as possible.

[0122] In possible embodiments, the reference liquid level height interval can be determined based on the height of the printing reference surface and the error boundary value. Wherein, the height of the printing reference surface and the error boundary value can be determined based on different performances of the 3D printing device, i.e. the printing reference surface includes the most ideal forming height in the 3D printing device, and the error boundary value includes the deviation value relative to the printing reference surface that can be allowed on the basis of meeting the minimum printing quality requirement. In an example, the error boundary value includes but is not limited to 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, etc. Assuming that the height of the printing reference surface is h, and the error boundary value is x, then the lower limit of the reference liquid level height interval is h-x, and the upper limit is h+x.

[0123] In an exemplary embodiment, after the liquid level height adjustment value is determined, the liquid level height of the photocurable material in the container can be controlled within the reference liquid level height interval as the target to adjust the liquid level height.

[0124] It can be understood that the liquid level adjustment includes two directions, i.e. adjusting the liquid level up or adjusting the liquid level down. Taking a top projection printing device as an example, during the 3D printing process, the carrying mechanism gradually immerses more into the photocurable material during the downward movement, resulting in the liquid level rising, at this time the liquid level needs to be adjusted down to balance the change of the liquid level caused by the descent of the carrying mechanism. However, due to the difficulty in accurately regulating the liquid level, in some embodiments, due to the limited adjustment accuracy of the liquid level control device, it is difficult to accurately calculate the height change of the liquid level after printing of at least one printing layer, and to accurately compensate for the change, so during the liquid level adjustment, even if the liquid level height adjustment value is determined based on the volume change of the carrying mechanism immersed in the photocurable material, when the liquid level is adjusted in the same adjustment direction based on the liquid level height adjustment value, the liquid level will not usually stabilize at a certain value or within a certain range, for example, the liquid level may change linearly. The linear change of the liquid level will cause the liquid level to exceed the upper limit or lower limit of the reference liquid level height interval, so the direction of the liquid level adjustment needs to be changed in time.

[0125] Based on this understanding, in an exemplary embodiment, the 3D printing device further determines the current liquid level adjustment direction based on the liquid level height adjustment value and the difference between the current liquid level height and the upper limit or lower limit of the reference liquid level height interval.

[0126] Here, in order to keep the liquid level height within the reference liquid level height interval, the liquid level position in the container can be determined by predicting the liquid level, for example, predicting the liquid level height after the liquid level adjustment according to the liquid level change during the printing process combined with the liquid level height adjustment value, and changing the liquid level adjustment direction when the liquid level height is about to exceed the reference liquid level height interval.

[0127] In other embodiments, the liquid level position in the container can also be detected every layer or every few layers, for this purpose, the 3D printing device further comprises a detection device, which can be connected with the interface unit of the 3D printing device control device to send detection data to the interface unit and provide the detection data to the processing unit for processing, the detection device includes but is not limited to a liquid level sensor and the like. When the detection device detects that the liquid level position exceeds or is about to exceed the upper limit or lower limit of the reference liquid level height interval, the liquid level adjustment direction can be changed. Therefore, in some embodiments, the liquid level adjustment method further comprises the step of detecting the liquid level height of the photocurable material in the container every interval of a preset number of layers. The preset number of layers can be 1 layer, 2 layers, 3 layers, 4 layers, 5 layers, 6 layers, 7 layers, 8 layers, 9 layers, 10 layers, 11 layers, 12 layers, 13 layers, 14 layers, 15 layers, 16 layers, 17 layers, 18 layers, 19 layers, 20 layers, etc., which can be configured according to actual needs so that the liquid level can be detected in time when it is about to exceed the reference liquid level height interval.

[0128] In some embodiments, before the liquid level is adjusted at each liquid level adjustment layer or every several liquid level adjustment layers, the liquid level in the container is detected. If the liquid level is close to the upper limit or the lower limit of the reference liquid level interval, or will exceed the upper limit or the lower limit of the reference liquid level interval after the liquid level is adjusted based on the liquid level adjustment value, the direction of the liquid level adjustment is opposite to the direction of the previous liquid level adjustment. Otherwise, if the liquid level is not close to the upper limit or the lower limit of the reference liquid level interval, or will not exceed the upper limit or the lower limit of the reference liquid level interval after the liquid level is adjusted based on the liquid level adjustment value, the direction of the liquid level adjustment is the same as the direction of the previous liquid level adjustment.

[0129] In an exemplary embodiment, referring to Figure 10 which shows a schematic diagram of the brief structure of a 3D printing device including a detection device in an embodiment of the present application. As shown in the figure, the 3D printing device includes a detection device 101. During the printing process, an energy radiation device 11 radiates energy 111 to the photocurable material in a container 12 to print layer by layer and obtain a 3D printed component 102 on a component platform 13. During the printing process, the detection device 101 detects the position of the liquid surface 121 of the photocurable material in the container 12 to provide data support for the liquid level adjustment.

[0130] Through the adjustment mode in the above embodiments of the present application, the change of the liquid level of the photocurable material in the container is smooth. After the liquid level is adjusted by the liquid level adjustment method in the above embodiments, the fluctuation of the liquid level presents a relatively smooth broken line rule, thereby reducing the time of the liquid surface flow and significantly improving the printing quality.

[0131] In an exemplary embodiment, if the current liquid level value is close to the upper limit or the lower limit of the reference liquid level interval, the liquid level adjustment value is reduced, thereby making the change of the liquid level more stable and reducing the obvious fluctuation of the liquid level caused by the change of the adjustment direction of the liquid level. Even if the liquid level change curve is changed when the adjustment direction of the liquid level is changed, it still presents a smooth curve similar to a sine wave.

[0132] In this case, the proximity can be determined according to actual needs, including but not limited to when the difference between the liquid level height and the upper or lower limit of the reference liquid level height interval reaches 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc. of the error boundary value. For example, taking the case where the difference between the liquid level height and the upper or lower limit of the reference liquid level height interval reaches 80% of the error boundary value, assuming that the height of the printing reference surface is h, and the error boundary value is x, then the lower limit of the reference liquid level height interval is h-x, and the upper limit is h+x, and the current liquid level height is y, when the difference between y and h-x reaches 0.8x, or the difference between y and h+x reaches 0.8x, the liquid level height adjustment value is reduced. It should be understood that the above description of proximity is only for explanation and not limitation, and in actual application, the liquid level height adjustment value can be reduced under what circumstances to improve the printing quality.

[0133] In this case, the specific amount of reduction can also be configured according to actual needs, for example, the liquid level height adjustment value can be reduced by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, etc.

[0134] In an exemplary embodiment, since there is also consumption of photocurable material after the printing material is solidified into a pattern solidification layer during printing, in some embodiments, the 3D printing device also determines the liquid level height adjustment value corresponding to the at least one printing layer based on the consumption of photocurable material required when printing the at least one slice image. That is, the volume of the carrying mechanism immersed in the photocurable material when printing the at least one slice image and the consumption of photocurable material required when printing the at least one slice image are used to determine the liquid level height adjustment value, so that the adjustment accuracy is higher.

[0135] In an exemplary embodiment, the liquid level adjustment in the container can be achieved by a liquid level adjustment device.

[0136] In an embodiment, the liquid level height adjustment of the photocurable material in the container is achieved by adjusting the height of the container. It can be understood that the purpose of adjusting the liquid level height is to make the distance between the forming surface and the energy radiation device within the ideal range, so as to make the printing quality higher. In the top projection printing device, the forming surface is usually located at the uppermost of the liquid surface, so by adjusting the height of the container, the distance between the liquid surface and the energy radiation device can also be adjusted, thereby achieving the adjustment of the liquid level. Of course, the adjusted liquid level height in this embodiment does not refer to the height of the liquid surface in the container relative to the bottom surface of the container, because only changing the height of the container will not affect the height of the liquid surface in the container relative to the bottom surface of the container, so it can be understood that the changed liquid level height in this embodiment refers to the height of the liquid surface in the container relative to the horizontal plane where the printing device is located.

[0137] In a possible implementation, a lifting mechanism can be provided at the bottom of the container, so as to drive the lifting or lowering of the container by the lifting mechanism. The lifting mechanism can be a screw rod transmission lifting mechanism, or a "liquid level adjustment system" as described in the application No. CN2020227710185, which includes a lifting mechanism and a driving mechanism. The lifting mechanism is arranged at the bottom of the container and is used to drive the container to move up and down. The driving mechanism is connected with the lifting mechanism and is used to drive the lifting mechanism to adjust the liquid level position of the to-be-formed material contained in the container when receiving a control instruction. In the application No. CN2020227710185, the "liquid level adjustment system" corresponds to the liquid level adjustment device in the present application, or the lifting mechanism can also adopt other structures in the prior art to realize the lifting of the container. Since the structure for driving the lifting of the container is not the point of the present application, it will not be described here. In some embodiments, the lifting mechanism can be connected with the control device of the 3D printing device, so as to be controlled by the control device to realize the lifting of the container. In other embodiments, the lifting mechanism can also be connected with the control device of the 3D printing device, so as to be driven by the control device to realize the lifting of the container.

[0138] In another embodiment, the liquid level of the photocurable material in the container is adjusted by adjusting the volume of the balancing device immersed in the photocurable material. The balancing device includes, but is not limited to, the balancing block in the 3D printing device, i.e. the volume of the balancing block immersed in the photocurable material in the container is used to control the liquid level in the container. It should be understood that the balancing block in the 3D printing device is a structure that can move up and down in the container, which is usually a regular cuboid or cubic structure, so as to facilitate the calculation of the change brought by the liquid level when it is lowered, and the volume of the balancing block is usually determined based on the size of the container.

[0139] In possible embodiments, the balancing device can be partially or fully immersed in the photocurable material in the container during the printing process. The balancing device can be connected to the 3D printing device, so as to be controlled by the control device to realize lifting and lowering, and to control the liquid level by adjusting the volume of the photocurable material immersed.

[0140] In another embodiment, the liquid level of the photocurable material in the container is adjusted by the liquid supplementing device to deliver or extract the photocurable material into the container. Here, when it is necessary to raise the liquid level in the container, the photocurable material can be delivered into the container, and when it is necessary to lower the liquid level in the container, the photocurable material can be extracted from the container.

[0141] In possible embodiments, the liquid supplementing device can be connected to the control device of the 3D printing device, so as to be controlled by the control device to deliver or extract the photocurable material. In other embodiments, the lifting mechanism can also be connected to the control device of the 3D printing device, so as to be controlled by the control device to deliver or extract the photocurable material, so as to adjust the liquid level of the photocurable material in the container. The liquid supplementing device includes a delivery pipeline and a delivery pump capable of providing negative pressure or positive pressure arranged on the pipeline, and the two ends of the delivery pipeline are respectively connected to the container and a storage device of the photocurable material, such as a resin barrel or other container for storing the photocurable material. The storage device is usually sealed in a non-use state to avoid the performance of the internal photocurable material being affected by long-term exposure to air. In some cases, a filtering mechanism can also be arranged on the delivery pipeline, so as to avoid the impurities in the container being brought into the storage device of the photocurable material when the photocurable material is extracted from the container of the 3D printing device.

[0142] In one exemplary embodiment, the volume change of the light-curing material that the carrying mechanism is immersed in during the movement of each layer causes the change of the liquid level, thus the change of the liquid level can be calculated according to the movement amount of the carrying mechanism and the physical parameters of the carrying mechanism, provided that the physical parameters of the carrying mechanism are known. In this embodiment, the 3D printing device can further comprise a storage unit for storing the physical parameters of the carrying mechanism in the 3D printing device, which include but are not limited to the bottom surface area, thickness, size of the supporting arm, etc. of the component platform in the carrying mechanism. The interface unit is used to obtain the movement amount of the carrying mechanism during the printing process of at least one printing layer, so that the processing unit calculates the volume change of the light-curing material that the carrying mechanism is immersed in during the printing process of at least one printing layer according to the movement amount, and thus obtains the liquid level adjustment amount.

[0143] In a possible implementation, the 3D printing device can also have an external input unit, such as a keyboard, etc. The external input unit is connected to the interface unit, and the operator can input the movement amount of the carrying mechanism during the printing process of at least one printing layer through the external input unit. The interface unit provides the movement amount to the processing unit, so that the processing unit calls the physical parameters of the carrying mechanism in the storage unit and calculates the liquid level adjustment amount in combination with the movement amount.

[0144] In one exemplary embodiment, the volume change of the light-curing material that the carrying mechanism is immersed in during the printing process of at least one printing layer can also be obtained externally.

[0145] In one exemplary embodiment, the 3D printing device further comprises a coating mechanism. Before the step of allowing the energy radiation device to irradiate the slice image in the 3D component model to the filled printing material to obtain a pattern solidified layer, the step further comprises: allowing the coating device to uniformly coat the light-curing material on the printing reference surface. In a possible implementation, the coating mechanism includes but is not limited to a scraper, a nozzle, etc. to uniformly coat the light-curing material on the printing reference surface, so as to reduce the flow leveling time of the light-curing material, improve the flatness of the liquid surface, and ensure the printing quality.

[0146] In one embodiment, the coating mechanism can be arranged above the container and uniformly coat the light-curing material on the printing reference surface during the movement from one side of the container to the other side. In a possible implementation, the coating mechanism comprises a guide rail and a coating scraper. The guide rail extends back and forth between the opposite sides of the container, and the coating scraper comprises a mounting beam arranged on the guide rail at the opposite sides of the container, a scraper main cavity arranged on the mounting beam, and a blade assembly arranged at the bottom of the scraper main cavity. The blade assembly comprises a flexible scraper blade made of soft material.

[0147] The present application also provides a 3D printing method. Please refer to Figure 9which shows a schematic diagram of the 3D printing method in an embodiment of the present application. As shown in the figure, in step S210, the height of the bearing mechanism is adjusted to fill the printing material to be solidified in the printing reference surface. Then in step S220, the energy radiation device irradiates the slice image in the 3D component model to the filled printing material to obtain a pattern solidification layer. In step S230, the steps of S210 and S220 are repeated to accumulate the pattern solidification layers on the component platform, thereby forming the corresponding 3D component. Among them, during the printing process, the 3D printing equipment adjusts the liquid level height of the photocuring material in the container based on the liquid level adjustment method in the above-mentioned embodiments, such as Figures 1 to 8 Corresponding embodiments, so that the printed 3D component has better surface precision and quality, which will not be described here.

[0148] In some embodiments, for example in a top projection printing device, when printing the first few layers, it is difficult to visually distinguish the distance between the pattern solidification layer attached to the component platform and the liquid surface, so the liquid level is first adjusted to the position of the printing reference surface, and then the component platform is lowered below the liquid surface to dip the photocuring material on the upper surface of the component platform, and then raised above the liquid surface, and then the component platform is lowered below the liquid surface to dip the photocuring material, and then raised to a distance of one layer thickness above the previous printing layer, and then solidified for one layer. Repeat the process of lowering the component platform below the liquid surface to dip the photocuring material, raising the component platform above the liquid surface and moving a distance of one layer thickness above the previous printing layer, and solidifying the current layer until the component platform is located below the liquid surface during the process of gradually lowering the component platform. At this time, since the pattern solidification layer on the component platform has accumulated multiple layers, the component platform can be moved in a way of gradually lowering without being raised again during the printing process of the subsequent pattern solidification layer, and the liquid level of the photocuring material is adjusted according to the aforementioned liquid level adjustment method until the printing is completed. Then the component platform is raised to take out the printed 3D component.

[0149] It should be understood that although the top exposure printing device is used as an example in the above-mentioned embodiments, the printing device can also be a bottom exposure printing device in actual application. In the bottom exposure printing device, the energy radiation device is located below the container, and the Z-axis driving mechanism is used to control the position of the component platform along the Z-axis direction to form a printing reference surface between the lower surface of the component platform and the lower surface of the container. Although the position of the liquid surface has less effect on printing in the bottom exposure printing device, the liquid level can still be adjusted by the technical idea in the present application to ensure better printing effect.

[0150] In one or more exemplary aspects, the functions described with the methods of the present application can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media include computer-readable storage media. A computer-readable storage medium can be any available medium or

[0151] The flow diagrams and block diagrams in above-described figures of the present application illustrate the architecture, functionality, and operation of possible implementations of systems, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flow diagrams or block diagrams can represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that in some alternative implementations, the functions noted in the blocks can occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and / or flow diagrams, and combinations thereof, can be implemented by special purpose hardware-based systems that perform the specified functions or operations, or combinations of special purpose hardware and computer instructions.

[0152] The above-described embodiments of the application are merely illustrative of the principles of the present application and are not intended to limit the scope of the application. Any modification or variation which comes within the scope of the preferred embodiments is intended to fall within the scope of the application. Therefore, it is intended that the application not be limited to the precisely as shown and described, and that variations thereof can be made.

Claims

1. A liquid level regulating method, characterized by, A method for adjusting a liquid level of a photocurable material in a container of a 3D printing device, the 3D printing device further comprising a support mechanism for supporting a 3D object during a printing operation, the method comprising the steps of: determining a liquid level adjustment value corresponding to at least one printing layer based on a volume change of the support mechanism immersed in the photocurable material during a printing process of the at least one printing layer; determining a current liquid level adjustment direction for adjusting the liquid level of the photocurable material in the container based on the liquid level adjustment value and a difference between a current liquid level and an upper limit or a lower limit of a reference liquid level interval, and keeping the liquid level within the reference liquid level interval, comprising: if the current liquid level is close to the upper limit or the lower limit of the reference liquid level interval, or will exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjustment value, then the liquid level adjustment direction is opposite to a previous liquid level adjustment direction; and if the current liquid level is not close to the upper limit or the lower limit of the reference liquid level interval, or will not exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjustment value, then the liquid level adjustment direction is the same as the previous liquid level adjustment direction.

2. The liquid level regulating method according to claim 1, characterized in that, if the current liquid level is close to the upper limit or the lower limit of the reference liquid level interval, then the liquid level adjustment value is decreased.

3. The liquid level regulating method according to claim 1, characterized in that, The method further comprises a step of detecting the liquid level of the photocurable material in the container after every interval of a preset number of layers.

4. The liquid level regulating method according to claim 1, characterized by, The method further comprises: determining the liquid level adjustment value corresponding to the at least one printing layer based on a required consumption of the photocurable material during printing of at least one slice image.

5. The liquid level regulating method according to claim 1, characterized by, The liquid level adjustment of the photocurable material in the container is achieved by adjusting a height of the container.

6. The liquid level regulating method according to claim 1, characterized by, The liquid level adjustment of the photocurable material in the container is achieved by adjusting a volume of the photocurable material immersed by a balancing device.

7. The liquid level regulating method according to claim 1, characterized by, The liquid level adjustment of the photocurable material in the container is achieved by delivering or pumping the photocurable material into or out of the container by a liquid supplementing device.

8. The liquid level regulating method according to claim 1, characterized by, The 3D printing device is a top projection 3D printing device.

9. The liquid level regulating method according to claim 1, characterized in that, The reference liquid level interval is determined based on a height of a reference surface printed by the 3D printing device and an error boundary value.

10. A liquid level regulating system characterized by, A system for adjusting a liquid level of a photocurable material in a container of a 3D printing device, the 3D printing device further comprising a support mechanism for supporting a 3D object during a printing operation, the system comprising: a processing module for determining a liquid level adjustment value corresponding to at least one printing layer based on a volume change of the support mechanism immersed in the photocurable material during a printing process of the at least one printing layer; the processing module is further configured to determine a current liquid level adjustment direction based on the liquid level adjustment value and a difference between a current liquid level and an upper limit or a lower limit of a reference liquid level interval, comprising: if the current liquid level is close to the upper limit or the lower limit of the reference liquid level interval, or will exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjustment value, then the liquid level adjustment direction is opposite to a previous liquid level adjustment direction; and if the current liquid level is not close to the upper limit or the lower limit of the reference liquid level interval, or will not exceed the upper limit or the lower limit of the reference liquid level interval after adjusting the liquid level based on the liquid level adjustment value, then the liquid level adjustment direction is the same as the previous liquid level adjustment direction. If the current liquid level height is not close to the upper limit or lower limit of the reference liquid level height interval, or after adjusting the liquid level based on the liquid level adjustment value, the liquid level does not exceed the upper limit or lower limit of the reference liquid level height interval, the liquid level adjustment direction is the same as the previous liquid level adjustment direction; The adjustment module is used to adjust the liquid level height of the photocurable material in the container based on the liquid level adjustment value, and keep the liquid level height in the reference liquid level height interval.

11. The fluid level regulating system of claim 10, wherein, If the current liquid level height is close to the upper limit or lower limit of the reference liquid level height interval, the processing module reduces the liquid level adjustment value.

12. The fluid level regulating system of claim 10, wherein, Also includes: The detection module is used to detect the liquid level height of the photocurable material in the container after every interval of a preset number of layers.

13. The fluid level regulating system of claim 10, wherein, The liquid level height adjustment of the photocurable material in the container is achieved by adjusting the height of the container.

14. The fluid level regulating system of claim 10, wherein, The liquid level height adjustment of the photocurable material in the container is achieved by adjusting the volume of the photocurable material that a balancing device sinks into.

15. The fluid level regulating system of claim 10, wherein, The liquid level height adjustment of the photocurable material in the container is achieved by delivering or extracting photocurable material into the container by a liquid supplementing device.

16. The fluid level regulating system of claim 10, wherein, The 3D printing device is a top projection 3D printing device.

17. The fluid level regulating system of claim 10, wherein, The reference liquid level height interval is determined based on the height of the printing reference surface of the 3D printing device and the error boundary value.

18. The fluid level regulating system of claim 10, wherein, Also includes: The storage module stores the physical parameters of the carrying mechanism in the 3D printing device; The interface module is used to obtain the movement amount of the carrying mechanism in the 3D printing device during the printing process of at least one printing layer, so that the processing module calculates the volume change of the carrying mechanism immersed in the photocurable material during the printing process of the at least one printing layer based on the movement amount.

19. The fluid level regulating system of claim 18, wherein, The interface module is also used to obtain the slice image in the 3D component model, so that the processing module determines the liquid level adjustment value corresponding to the at least one printing layer based on the consumption of photocurable material required during the printing of at least one slice image.

20. A method of 3D printing, characterized in that, For a 3D printing device, the 3D printing device includes an energy radiation device, a carrying mechanism, and a container for holding photocurable material, and the 3D printing method includes: Adjust the height of the carrying mechanism to fill the printing material to be solidified on the printing reference surface; Make the energy radiation device irradiate the slice image in the 3D component model to the filled printing material to obtain a pattern solidification layer; Repeat the above steps to accumulate pattern solidification layers on the component platform, thereby forming a corresponding 3D component; wherein during the printing process, the 3D printing device adjusts the liquid level height of the photocurable material in the container based on the liquid level adjustment method as claimed in any one of claims 1-9.

21. The 3D printing method of claim 20, wherein, The 3D printing device is a top projection 3D printing device, and the 3D printing device further includes a coating mechanism, and before the step of making the energy radiation device irradiate the slice image in the 3D component model to the filled printing material to obtain a pattern solidification layer, the step further includes: making the coating mechanism uniformly coat the photocurable material on the printing reference surface.

22. A 3D printing device, characterized by It includes: A container for holding the material to be solidified; An energy radiation device located above or below the container for irradiating energy to the photocurable material in the container according to the slice image, so that the photocurable material is solidified and formed; A bearing mechanism comprising a support arm, and a component platform connected to the support arm, the support arm being partially located in the container during a printing operation, the component platform being located in the container during the printing operation and used to accumulate and attach pattern solidification layers to form a corresponding 3D component layer by layer; A Z-axis driving mechanism connected to the support arm, used to adjust the height of the component platform in the Z-axis direction, so as to adjust the distance between the component platform and the printing reference surface during the printing operation; A control device connected to the energy radiation device and the Z-axis driving mechanism, used to control the energy radiation device and the Z-axis driving mechanism during the printing operation, so as to accumulate and attach pattern solidification layers on the component platform to form a corresponding 3D component based on the 3D printing method as claimed in claim 20 or 21.

23. The 3D printing device of claim 22, wherein, The 3D printing device further comprises a lifting mechanism connected to the control device and the container, used to drive the container to move up and down under the control of the control device, so as to adjust the liquid level of the photocurable material in the container by adjusting the height of the container.

24. The 3D printing device of claim 22, wherein, Further comprising: A balancing device connected to the control device, used to move under the control of the control device, so as to adjust the liquid level of the photocurable material in the container by adjusting the volume of the balancing device immersed in the photocurable material.

25. The 3D printing device of claim 22, wherein, Further comprising: A liquid supplementing device connected to the control device and the container, used to deliver or extract the photocurable material into the container under the control of the control device, so as to adjust the liquid level of the photocurable material in the container.

26. The 3D printing device of claim 22, wherein, The 3D printing device further comprises a detection device located above the container, connected to the control device, used to detect the liquid level of the photocurable material in the container.

27. The 3D printing device of claim 22, wherein, The 3D printing device is a top projection 3D printing device, and the 3D printing device further comprises a coating mechanism arranged above the container, used to uniformly coat the photocurable material on the printing reference surface during the movement from one side of the container to the other side.

Images