Apparatus, method and non-transitory storage medium for forming a three-dimensional object

Abstract

The application discloses a kind of equipment, method and nonvolatile storage medium for forming three-dimensional object.It relates to the field of 3D printing technology, the equipment includes: forming platform, three-dimensional object is formed on forming platform;Tray, forming platform and the forming surface between tray form for printing area;Optical module, for irradiating printing area;Controller, for controlling forming platform movement in printing process, so that forming platform and polymerizable liquid contact;Detection component, for obtaining liquid change state in the process that forming platform and polymerizable liquid contact;Controller is used to determine whether liquid layer thickness tends to be stable according to liquid change state, and controls optical module to irradiate printing area when liquid layer thickness tends to be stable.The application solves the technical problems that the pre-exposure waiting time applicability is poor and the hollow or printing layer thickness is not uniform in the related art based on the experience value to determine whether 3D printing ends exposure pre-waiting and enters exposure phase.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of 3D printing, in particular to a device, a method and a non-volatile storage medium for forming a three-dimensional object. BACKGROUND

[0002] The pre-exposure waiting time in 3D printing refers to a period of time before each layer is exposed, during which the printing platform is stationary for the excess liquid resin to be drained out of the platform and the resin to be backflowed. The purpose of the pre-exposure waiting time is to ensure that the light-cured material can uniformly cover the entire printing platform and adhere to the previously printed layer, thereby maintaining the stability of the printing layer thickness. In the 3D printing process, the pre-exposure waiting time needs to be controlled. However, in the related art, whether the 3D printing ends the pre-exposure waiting and enters the exposure phase is mainly determined based on an empirical value. The setting of the empirical value may not ensure the uniformity of the thickness of each layer of the three-dimensional object, and may easily cause the problems of voids or uneven printing. Moreover, the setting of the empirical value may not take into account the changes in material properties or device performance, resulting in the inapplicability of the pre-exposure waiting time.

[0003] At present, there is no effective solution to the above problems. SUMMARY

[0004] The embodiments of the present application provide a device, a method and a non-volatile storage medium for forming a three-dimensional object, to at least solve the technical problems of poor applicability of the pre-exposure waiting time, and easy occurrence of voids or uneven printing layer thickness caused by determining whether the 3D printing ends the pre-exposure waiting and enters the exposure phase based on an empirical value in the related art.

[0005] According to another aspect of the embodiments of the present application, a device for forming a three-dimensional object is also provided, which comprises: a forming platform, on which the three-dimensional object is formed; a tray having a construction surface, a printing area for filling a polymerizable liquid being formed between the forming platform and the construction surface; an optical module for irradiating the printing area to form a solid or semi-solid polymer from the polymerizable liquid; a controller configured to be connected with the forming platform, for controlling the movement of the forming platform to make the forming platform contact with the polymerizable liquid during the printing process; a detection assembly for acquiring a liquid change state during the contact of the forming platform with the polymerizable liquid; the controller is configured to be communicatively connected with the detection assembly and the optical module, for judging whether the liquid layer thickness tends to be stable according to the liquid change state, and for issuing an exposure instruction to the optical module to make the optical module irradiate the printing area when it is judged that the liquid layer thickness tends to be stable.

[0006] Optionally, the controller is further configured to: control the forming platform to wait or adjust the waiting time of the forming platform or adjust the movement speed of the forming platform when it is judged that the liquid layer thickness does not tend to be stable.

[0007] Optionally, the detection component comprises one or more of a force sensor, a displacement sensor, a flow rate sensor, an ultrasonic sensor, a laser radar sensor, a photoelectric sensor, a strain gauge sensor; the liquid change state is obtained from one or more of a force value, a displacement change amount, a liquid flow rate, a liquid level height, a tray deformation amount.

[0008] Optionally, the detection component comprises a force sensor, and the controller is configured to: acquire a plurality of force values detected by the force sensor on the molding platform at different times, wherein the force sensor is configured to acquire the force value applied to the molding platform during contact between the molding platform and the polymerizable liquid; and determine whether the liquid layer thickness tends to be stable according to the plurality of force values.

[0009] Optionally, determining whether the liquid layer thickness tends to be stable according to the plurality of force values comprises: performing difference operation on the force values respectively detected by the molding platform at two adjacent times to obtain a force value change amount; calculating a time interval between the two adjacent times; performing division operation on the force value change amount and the time interval to obtain a force value change rate; determining whether the force value change rate is less than a preset change rate threshold; and determining that the liquid layer thickness tends to be stable in a case where the force value change rate is less than the preset change rate threshold.

[0010] Optionally, determining whether the liquid layer thickness tends to be stable according to the plurality of force values comprises: determining whether the currently acquired force value is within a preset force value threshold range; and determining that the liquid layer thickness tends to be stable in a case where the currently acquired force value is within the preset force value threshold range.

[0011] Optionally, the detection component comprises a displacement sensor, and the controller is configured to: acquire a plurality of distance values detected by the displacement sensor, wherein the displacement sensor is configured to be arranged on the molding platform to acquire the distance value between the molding platform and the construction surface; and determine whether the liquid layer thickness tends to be stable according to the plurality of distance values.

[0012] Optionally, determining whether the liquid layer thickness tends to be stable according to the plurality of distance values comprises: determining whether the currently acquired distance value is within a preset distance threshold range; and determining that the liquid layer thickness tends to be stable in a case where the currently acquired distance value is within the preset distance threshold range.

[0013] Optionally, determining whether the liquid layer thickness tends to be stable according to the plurality of distance values comprises: performing difference operation on the distance values respectively between the molding platform and the construction surface at two adjacent times to obtain a distance change amount; calculating a time interval between the two adjacent times; performing division operation on the distance change amount and the time interval to obtain a distance change rate; determining whether the distance change rate is less than a preset change rate threshold; and determining that the liquid layer thickness tends to be stable in a case where the distance change rate is less than the preset change rate threshold.

[0014] Optionally, the detection component comprises a flow rate sensor, and the controller is configured to: acquire a liquid flow rate detected by the flow rate sensor, wherein the flow rate sensor is configured to collect the liquid flow rate at the bottom of the tray during the contact between the molding platform and the polymerizable liquid; and determine that the liquid layer thickness tends to be stable when the liquid flow rate is less than or equal to a preset speed threshold.

[0015] Optionally, the detection component comprises an ultrasonic sensor or a laser radar sensor, and the controller is configured to: acquire a liquid level height in the tray detected by the ultrasonic sensor or the laser radar sensor, wherein the ultrasonic sensor or the laser radar sensor is configured to collect the liquid level height in the tray during the contact between the molding platform and the polymerizable liquid; and determine whether the liquid layer thickness tends to be stable according to the liquid level height.

[0016] Optionally, determining whether the liquid layer thickness tends to be stable according to the liquid level height comprises: performing a difference operation on liquid level heights corresponding to two adjacent time instants respectively to obtain a liquid level difference; calculating a time interval between the two adjacent time instants; performing a division operation on the liquid level difference and the time interval to obtain a liquid level height change rate of the tray; determining whether the liquid level height change rate is less than or equal to a preset height change rate; and determining that the liquid layer thickness tends to be stable when the liquid level height change rate is less than or equal to the preset height change rate.

[0017] Optionally, determining whether the liquid layer thickness tends to be stable according to the liquid level height comprises: determining whether the liquid level height continuously tends to be stable within a preset height threshold range; and determining that the liquid layer thickness tends to be stable when the liquid level height continuously is within the preset height threshold range for a preset time.

[0018] Optionally, the detection component comprises a photoelectric sensor or a strain gauge sensor, and the controller is configured to: acquire a deformation amount of the construction surface detected by the photoelectric sensor or the strain gauge sensor, wherein the photoelectric sensor or the strain gauge sensor is configured to collect the deformation amount of the construction surface during the contact between the molding platform and the polymerizable liquid; and determine that the liquid layer thickness tends to be stable when the deformation amount is greater than or equal to a preset deformation amount threshold.

[0019] Optionally, the controller is further configured to: acquire a waiting time length from a starting time instant when the molding platform moves to the preset position to a time instant when it is determined that the liquid layer thickness tends to be stable; and determine whether the waiting time length is greater than a preset waiting time length; and send an exposure instruction to the optical module when the waiting time length is greater than or equal to the preset waiting time length.

[0020] Optionally, the controller is further configured to: control the molding platform to continue waiting until the waiting time length is greater than or equal to the preset waiting time length, or slow down the movement speed of the molding platform until the waiting time length is greater than or equal to the preset waiting time length, when the waiting time length is less than the preset waiting time length.

[0021] Optionally, the controller is further configured to, during the printing of the three-dimensional object, detect whether a current printing layer is a first set of slice layers of the three-dimensional object; and in a case where the current printing layer is not the first set of slice layers, control the detection component to acquire the liquid change state caused by the movement of the forming platform.

[0022] Optionally, during the printing of the three-dimensional object, the controller is further configured to: acquire a material type corresponding to the polymerizable liquid, and an actual waiting time of each slice layer corresponding to the three-dimensional object; wherein the actual waiting time is a waiting time of the forming platform before printing of each slice layer; and generate the printing parameter data packet according to the three-dimensional object, the material type corresponding to the polymerizable liquid, and the actual waiting time.

[0023] According to an aspect of an embodiment of the present application, a method for forming a three-dimensional object is also provided, which is implemented by a three-dimensional printing device, the three-dimensional printing device comprising a forming platform, on which the three-dimensional object is formed; a tray having a build surface, between which and the forming platform a printing area for filling a polymerizable liquid is formed; and an optical module for irradiating the printing area to form a solid or semi-solid polymer from the polymerizable liquid; the method comprising: controlling the movement of the forming platform to make the forming platform contact the polymerizable liquid; acquiring a liquid change state during the contact of the forming platform and the polymerizable liquid; and determining whether a liquid layer thickness tends to be stable according to the liquid change state, and issuing an exposure instruction to the optical module to make the optical module irradiate the printing area when it is determined that the liquid layer thickness tends to be stable.

[0024] According to another aspect of an embodiment of the present application, a non-volatile storage medium is also provided, which stores a plurality of instructions, the instructions being adapted to be loaded and executed by a processor to perform any one of the methods for forming a three-dimensional object.

[0025] In the embodiment of the present application, the three-dimensional object is formed on a forming platform; the tray has a build surface, a printing area for filling the polymerizable liquid is formed between the forming platform and the build surface; the optical module is used for irradiating the printing area to form a solid or semi-solid polymer from the polymerizable liquid; the controller is configured to be connected with the forming platform, and is used for controlling the movement of the forming platform to make the forming platform contact with the polymerizable liquid during the printing process; the detection assembly is used for acquiring the liquid change state during the contact of the forming platform with the polymerizable liquid; the controller is configured to be in communication connection with the detection assembly and the optical module, and is used for judging whether the liquid layer thickness tends to be stable according to the liquid change state, and is used for issuing an exposure instruction to the optical module to make the optical module irradiate the printing area when it is judged that the liquid layer thickness tends to be stable, so as to achieve the purpose of determining whether to end the pre-exposure waiting according to the liquid change state detected by the detection assembly in real time and accurately, thereby improving the accuracy and applicability of the pre-exposure waiting setting of 3D printing, avoiding the problems of voids or uneven printing layer thickness, and further solving the technical problems of poor applicability of the pre-exposure waiting time and easy occurrence of voids or uneven printing layer thickness caused by determining whether to end the pre-exposure waiting and enter the exposure stage of 3D printing based on the experience value in the related art. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0027] Figure 1 is a structural schematic diagram of an apparatus for forming a three-dimensional object according to an embodiment of the present application;

[0028] Figure 2 is a hardware structure block diagram of a computer terminal of a method for forming a three-dimensional object according to an embodiment of the present application;

[0029] Figure 3 is a flowchart of a method for forming a three-dimensional object according to an embodiment of the present application;

[0030] Figure 4 is a flowchart of an optional method for forming a three-dimensional object according to an embodiment of the present application;

[0031] Figure 5 is a flowchart of an optional method for forming a three-dimensional object according to an embodiment of the present application;

[0032] Figure 6 is a flowchart of an optional method for forming a three-dimensional object according to an embodiment of the present application. DETAILED DESCRIPTION

[0033] In order to better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts should fall within the protection scope of the present application.

[0034] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described accompanying drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0035] First, for the convenience of understanding the embodiments of the present application, the following will explain some terms or nouns involved in the present application:

[0036] The 3D printing technology based on light curing principle uses liquid photosensitive material (light curing resin) as raw material. Through the ultraviolet irradiation of photosensitive resin, the liquid material is solidified layer by layer into solid state, and the required object is constructed. In this process, after starting printing, the 3D printer will uniformly coat the liquid photosensitive resin on the workbench. Then, through the projection system at the bottom, a specific wavelength of light source is used to irradiate the photosensitive resin, so that it is solidified in a short time.

[0037] Layer by layer stacking: once the first layer is solidified, the printing platform will rise after each layer is solidified, so that the printed object is gradually extracted from the liquid material. Then the platform will drop a fixed distance to print the next slice layer. Then, the photosensitive resin is coated again and solidified. This process will be repeated layer by layer until the whole model is printed.

[0038] The pre-exposure waiting time in 3D printing refers to the time the printing platform is stationary before each layer is exposed for the excess liquid resin to drain out of the platform and the backflow of the resin. The purpose of this waiting time is to ensure that the light-cured material can uniformly cover the entire printing platform and adhere to the previously printed layer, so as to maintain the stability of the printing layer thickness.

[0039] In the 3D printing process, the pre-exposure waiting time needs to be controlled. A 3D printing pre-exposure waiting time prediction method is provided in the related art, which comprises: acquiring a slice image of a to-be-printed model, determining the maximum distance of a pixel point to be exposed from the model boundary based on an image processing algorithm; based on the maximum distance and a pre-constructed fitting curve of the liquid discharge radius and the waiting time, the predicted pre-exposure waiting time is obtained; wherein the pre-constructed fitting curve of the liquid discharge radius and the waiting time is as follows: real-time acquisition of the liquid discharge force data of the printing platform downward when printing a specific model; wherein the specific model needs to meet the condition that the liquid discharge radius gradually changes in the printing process; based on the obtained liquid discharge force data, the time variation curve of the cartridge deformation recovery amount is fitted based on the linear elastic theory; based on the time variation curve, the waiting time when the deformation recovery amount of each liquid discharge radius is less than a preset threshold is obtained, and then the fitting curve of the liquid discharge radius and the waiting time is obtained.

[0040] It can be seen that in the related art, the fitting curve needs to be constructed according to the liquid discharge force data of the printing platform downward based on the characteristic model. However, the empirical value setting may not ensure that the thickness of each layer of the three-dimensional object is uniform, and the problems of voids or uneven printing are prone to occur. And the empirical value setting may not take into account the characteristics of the material or the change of the device performance, resulting in that the pre-exposure waiting time is no longer applicable.

[0041] In order to solve the above problems, according to the embodiments of the present application, a device for forming a three-dimensional object is provided, comprising: a forming platform, on which a three-dimensional object is formed; a tray having a build surface, between which and the forming platform a printing area for filling a polymerizable liquid is formed; an optical module for irradiating the printing area to form a solid or semi-solid polymer from the polymerizable liquid; a controller configured to be connected with the forming platform for controlling the movement of the forming platform to make the forming platform contact with the polymerizable liquid during the printing process; a detection assembly for acquiring the liquid change state during the contact of the forming platform with the polymerizable liquid; the controller is configured to be in communication connection with the detection assembly and the optical module, for judging whether the liquid layer thickness tends to be stable according to the liquid change state, and for issuing an exposure instruction to the optical module to make the optical module irradiate the printing area when it is judged that the liquid layer thickness tends to be stable.

[0042] When performing 3D printing, a 3D model of the printed part can be established first, and then the 3D model of the printed part is sliced layer by layer. When printing, the first slice layer can be started from the first slice layer, and each slice layer can be printed in turn based on the successfully printed previous slice layers, and finally a complete 3D model of the printed part is obtained, that is, a three-dimensional object is finally formed. Figure 1 is a structural schematic diagram of the device for forming a three-dimensional object provided according to the embodiments of the present application, as Figure 1As shown, the device for forming a three-dimensional object provided by the embodiment of the application can generate a projection image according to the shape of each layer slice model when printing the layer slice model; the optical module 13 can be a light emitting mechanism, which can irradiate the projection image on the printing area in the tray 12 filled with the polymerizable liquid; the controller can control the movement of the forming platform during the printing process to make the forming platform contact the polymerizable liquid; during the process that the forming platform 11 contacts the polymerizable liquid, the detection assembly can collect the liquid change state corresponding to the polymerizable liquid in real time; the controller can determine whether the liquid layer thickness of the current layer slice model tends to be stable according to the liquid change state, and timely send an exposure instruction to the optical module under the condition that the liquid layer thickness tends to be stable; through the exposure instruction, the optical module 13 can be controlled to irradiate the printing area formed between the forming platform 11 and the construction surface, and the polymerizable liquid will be cured to form a solid or semi-solid polymer matching the projection image under the irradiation of the light emitted by the optical module, thereby completing the printing and forming of the layer slice model.

[0043] Optionally, the polymerizable liquid can be but is not limited to a liquid resin; the liquid layer thickness is used to indicate the distribution of the polymerizable liquid on the current printing layer in the actual printing process.

[0044] It should be noted that the detection assembly includes one or more of a force sensor, a displacement sensor, a flow rate sensor, an ultrasonic sensor, a laser radar sensor, a photoelectric sensor, and a strain gauge sensor; when the detection assembly is different types of sensors, the installation positions of the corresponding detection assemblies are different, for example, when the detection assembly is a force sensor, the sensor can be installed on the forming platform 11; when the detection assembly is a displacement sensor, the sensor can be installed on the forming platform 11; when the detection assembly is a flow rate sensor, the sensor can be installed at the bottom of the tray 12; when the detection assembly is an ultrasonic sensor or a laser radar sensor, the sensor can be installed on one side of the tray 12 for collecting the liquid level in the tray 12; when the detection assembly is a photoelectric sensor or a strain gauge sensor, the sensor can be installed at the bottom of the tray 12. In actual application, the number and installation position of the sensor can be set as needed, which will not be described here.

[0045] In the above process, the liquid change state of the polymerizable liquid during the contact between the forming platform and the polymerizable liquid is detected in real time by the detection assembly, and the controller can quickly and accurately determine whether the liquid layer thickness tends to be stable based on the liquid change state, and timely and accurately determine whether to end the pre-exposure waiting, so as to improve the accuracy and applicability of the pre-exposure waiting setting of 3D printing, avoid the problems of voids or uneven layer thickness, improve the efficiency and stability of 3D printing, and solve the technical problems of poor applicability of pre-exposure waiting time and easy occurrence of voids or uneven layer thickness caused by determining whether to end the pre-exposure waiting and enter the exposure stage based on experience value in the related art.

[0046] It should be noted that during the contact between the forming platform and the polymerizable liquid, the forming platform moves downward, causing the polymerizable liquid in the tray to overflow to the surrounding, so this process can also be referred to as a liquid discharge process. The device for forming a three-dimensional object provided by the embodiment of the present application can collect the liquid change state in real time and monitor the stability of the liquid layer thickness during the contact between the forming platform and the polymerizable liquid (i.e. the liquid discharge process), and determine the pre-exposure waiting time adaptively according to the real-time monitored stability of the liquid layer thickness, which can not only shorten the printing time, but also improve the consistency and stability in the 3D printing process. Moreover, since the embodiment of the present application can realize real-time collection of the liquid change state, the pre-exposure waiting time can be adaptively adjusted according to the liquid change state of different printing models and different types of polymerizable liquid (such as different viscosity resins), so as to improve the printing precision and efficiency, and has strong applicability. Since real-time monitoring can be performed, even for printing models with complex cross-section changes, the liquid layer thickness can be accurately determined, the layer thickness error can be reduced, and the printing surface quality can be improved.

[0047] As an optional embodiment, the controller is further configured to: when it is determined that the liquid layer thickness has not tended to be stable, control the forming platform to wait or adjust the waiting time of the forming platform or adjust the movement speed of the forming platform.

[0048] Optionally, when the liquid layer thickness has not tended to be stable, at least one of the following can be used to control the forming platform to continue waiting, prolong the waiting time, slow down the movement speed of the platform, or adjust the platform movement parameters, etc. When the movement speed of the forming platform is very slow, the influence on the polymerizable liquid is very small, which is approximately equal to waiting. During the waiting process of the forming platform, the polymerizable liquid is allowed to flow properly before light exposure, so as to ensure that the stable liquid layer thickness is maintained after deformation recovery, thereby ensuring the quality and precision of printing.

[0049] Optionally, during the printing of each layer of the slice model, when performing the current layer forming platform descending movement, the forming platform can be first lowered to a specified height at a faster speed, and before exposure at the specified height, the liquid layer thickness is waited until it tends to be stable; or after the forming platform is lowered to the specified height at a faster speed and the liquid layer thickness tends to be stable, the waiting time of the forming platform is adaptively adjusted according to the waiting time length. And because the forming platform is very slow, the influence on the liquid change state is very small, which is approximately equal to waiting, so the motion speed of the forming platform can be adjusted, for example, the forming platform is first lowered at a faster speed, and then the motion speed of the forming platform is slowed down after being lowered to the specified height, or the forming platform can be controlled to be lowered at a relatively stable speed during the whole descending process, so that the liquid change state tends to be as stable as possible and the liquid layer thickness tends to be as stable as possible.

[0050] As an optional embodiment, the detection assembly includes one or more of a force sensor, a displacement sensor, a flow rate sensor, an ultrasonic sensor, a laser radar sensor, a photoelectric sensor, and a strain gauge sensor; and the liquid change state is obtained from one or more of a force value, a displacement change amount, a liquid flow rate, a liquid level height, and a tray deformation amount.

[0051] Optionally, the liquid change state can be obtained by the detection assembly in real time during the contact between the forming platform and the polymerizable liquid. For example, the force value borne by the forming platform can be collected by the force sensor during the contact between the forming platform and the polymerizable liquid; the distance value between the forming platform and the construction surface can be detected by the displacement sensor, wherein the displacement change amount can be used to indicate the distance change amount between the forming platform and the construction surface collected at two adjacent time points; the liquid flow rate at the bottom of the tray can be collected by the flow rate sensor; the liquid level height in the tray can be collected by the ultrasonic sensor or the laser radar sensor; and the deformation amount of the construction surface of the tray can be collected by the photoelectric sensor or the strain gauge sensor.

[0052] It should be noted that the more comprehensive the liquid change state monitoring is, the more accurate and timely the liquid layer thickness can be detected to tend to be stable, so multiple of the force value, the displacement change amount, the liquid flow rate, the liquid level height, and the tray deformation amount can be used as the determination of the liquid change state to determine whether the liquid layer thickness tends to be stable more timely and accurately.

[0053] As an optional embodiment, the detection assembly includes a force sensor, and the controller is configured to: obtain multiple force values borne by the forming platform at different time points, wherein the force sensor is configured to obtain the force value applied to the forming platform during the contact between the forming platform and the polymerizable liquid; and determine whether the liquid layer thickness tends to be stable according to the multiple force values.

[0054] Optionally, the force sensor can be installed on the forming platform structure or the bottom structure of the exposure device (tray), and the force sensor can be one or more. When the force sensor is one, the force sensor can be installed at the middle position of the forming platform to monitor the overall force of the forming platform. When the force sensor is more than one, the force sensor can be installed at the four corners of the forming platform to monitor the force of the forming platform in different directions. When the force sensor is more than one, the average value of the force values collected by the multiple sensors at any moment can be used as the force value of the forming platform at the moment. The force sensor in the embodiment of the application can also monitor the force state of the forming platform and other structures during the printing process, and feed the real-time force value data to the controller for logical calculation.

[0055] Optionally, the force value of the forming platform can also be understood as the drainage force, and the corresponding force value change rate can be understood as the drainage force change rate. The drainage force is an important physical effect in the process of photocuring printing. In the process of photocuring printing, the polymerizable liquid is injected into the tank, and the printing platform is gradually pressed down, so that the polymerizable liquid is subjected to pressure and starts to drain to the edge of the forming platform. During this process, the polymerizable liquid will generate a reaction force on the forming platform, which is called drainage force (hereinafter referred to as drainage force). The size of the drainage force is related to the pressing speed of the forming platform, the fluidity of the resin, the geometry of the tank, the consistency of the equipment, the environment and other factors. The drainage force value change rate during the waiting process can be obtained by monitoring the force sensor arranged at the corresponding position (such as the top) of the forming platform or the corresponding position (such as the bottom) of the tray in real time, so as to judge whether the liquid layer thickness is stable. If it is detected that the liquid layer thickness has stabilized, the exposure of the next slice layer is directly entered, so as to save the printing time, improve the printing efficiency, and improve the precision and quality of the printed part. It should be noted that the 3D printing process includes exposure-peeling-descending-waiting-exposure (next layer). When the forming platform stops moving to the specified position according to the process package parameters, the liquid resin is extruded and discharged out of the plane during the descending process of the forming platform until the liquid layer thickness is stable. The drainage force value and the force value of the forming platform are changing all the time during this process.

[0056] It should be noted that by real-time acquisition of the multiple force values of the forming platform, the change of the liquid layer thickness can be monitored in real time, and the fluctuation degree of the liquid layer thickness can be found in time. Based on the feedback of the force values, the liquid layer thickness during printing can be precisely adjusted to ensure the printing quality and stability. Real-time monitoring of whether the liquid layer thickness tends to be stable based on the force values collected by the force sensor can effectively reduce deformation and defects during printing, improve printing quality, and avoid unnecessary repeated printing and waste of materials, saving costs and time. Determining whether the liquid layer thickness tends to be stable based on the real-time collected force values also has certain adaptability, so that during the printing process, the determination of whether the printing layer thickness tends to be stable can be made in time according to the actual situation during the printing process, so as to better adapt to different printing requirements and material characteristics.

[0057] As an optional embodiment, determining whether the liquid layer thickness tends to be stable according to the multiple force values comprises: performing difference operation on the force values respectively received by the forming platform at two adjacent time points to obtain a force value change amount; calculating a time interval between the two adjacent time points; performing division operation on the force value change amount and the time interval to obtain a force value change rate; determining whether the force value change rate is less than a preset change rate threshold; and in the case that the force value change rate is less than the preset change rate threshold, determining that the liquid layer thickness tends to be stable.

[0058] Optionally, during the printing process of each slice layer, when the descending movement of the forming platform corresponding to the current printing layer is performed, multiple force values collected by the force sensor at different time points during the contact process of the forming platform and the polymerizable liquid (i.e. the liquid discharge process) are obtained, based on the force value change amount between the force values respectively corresponding to two adjacent time points, the time interval between the two adjacent time points is divided to obtain the force value change rate of the forming platform, which can also be understood as the liquid discharge force change rate of the forming platform; it is further determined whether the force value change rate is less than the corresponding preset change rate threshold, and after successful determination, it is considered that the liquid layer thickness is stable and the liquid discharge of the forming platform tends to be stable, at this time it is determined that the waiting time is sufficient, and the next printing process is performed, such as the exposure process of the next slice layer.

[0059] As an optional embodiment, determining whether the liquid layer thickness tends to be stable according to the multiple force values comprises: determining whether the currently collected force value is within a preset force value threshold range; and in the case that the currently collected force value is within the preset force value threshold range, determining that the liquid layer thickness tends to be stable.

[0060] Optionally, the current collected force value can be one or more of a plurality of force values borne by the forming platform at different times, and in the case where the current collected force value is one, the liquid layer thickness can be determined to be stable when the one force value is within a preset force value threshold range, wherein the one force value is the latest collected force value in the plurality of force values. In order to avoid inaccurate determination of whether the liquid layer thickness is stable due to the mutation or contingency of a single force value, the current collected force value can be set to a plurality of force values, and in this case, the liquid layer thickness can be determined to be stable when all the plurality of force values are within the preset force value threshold range, or the liquid layer thickness can be determined to be stable when the average of the plurality of force values is within the preset force value threshold range, thereby timely and accurately determining whether the current liquid layer thickness is stable. The preset force value threshold is a preset liquid discharge force threshold in the printing process database, which can be set to one threshold based on one printing process, or different thresholds for each slice layer, without limitation. For example, the preset force value threshold can be a preset force value threshold matched with the current printing layer determined from the printing process database.

[0061] As an optional embodiment, the detection assembly includes a displacement sensor, and the controller is configured to: obtain a plurality of distance values detected by the displacement sensor, wherein the displacement sensor is configured to be arranged on the forming platform to collect distance values between the forming platform and the construction surface; and determine whether the liquid layer thickness is stable according to the plurality of distance values.

[0062] Optionally, the displacement sensor can be arranged on the main shaft connected to the forming platform, and used to collect distance values between the forming platform and the construction surface during the contact process of the forming platform and the polymerizable liquid (i.e., the liquid discharge process). Since the forming platform and the construction surface form a printing area for filling the polymerizable liquid, the distance values between the forming platform and the construction surface can reflect the formation of the printing area, such as whether the printing area is formed stably, and further determine whether the liquid layer thickness is stable. Therefore, by monitoring a plurality of distance values between the forming platform and the construction surface at different times in real time through the displacement sensor, whether the liquid layer thickness is stable can be determined timely and accurately. If it is detected based on the plurality of distance values collected by the displacement sensor that the liquid layer thickness has stabilized, the exposure of the next slice layer is directly entered, achieving the effect of saving printing time, improving printing efficiency, and improving the precision and quality of the printed part.

[0063] As an optional embodiment, determining whether the liquid layer thickness is stable according to the plurality of distance values includes: determining whether a currently collected distance value is within a preset distance threshold range; and determining that the liquid layer thickness is stable in the case where the currently collected distance value is within the preset distance threshold range.

[0064] Optionally, the current collected distance value can be one or more of the plurality of distance values detected by the displacement sensor, and in the case where the current collected distance value is one, the liquid layer thickness region can be determined to be stable when the one distance value, which is the latest collected distance value among the plurality of force values, is within the preset distance threshold range. To avoid inaccurate determination of whether the liquid layer thickness tends to be stable due to the mutation or contingency of a single distance value, the current collected distance value can be set to be a plurality of distance values, and in this case, the liquid layer thickness can be determined to tend to be stable when all the plurality of distance values are within the preset distance value threshold range, or the liquid layer thickness can be determined to tend to be stable when the average value of the plurality of distance values is within the preset distance value threshold range. Thus, it can be determined in a timely and accurate manner whether the current liquid layer thickness tends to be stable.

[0065] As an optional embodiment, determining whether the liquid layer thickness tends to be stable according to the plurality of distance values includes: performing difference operation on distance values between the forming platform and the build surface at two adjacent time instants to obtain a distance change amount; calculating a time interval between the two adjacent time instants; performing division operation on the distance change amount and the time interval to obtain a distance change rate; determining whether the distance change rate is less than a preset change rate threshold; and in the case where the distance change rate is less than the preset change rate threshold, determining that the liquid layer thickness tends to be stable.

[0066] Optionally, the distance change amount is used to indicate the distance change between the forming platform and the build surface at two adjacent time instants. During the printing of each slice layer, when the lowering movement of the forming platform corresponding to the current printing layer is performed, a plurality of distance values collected by the displacement sensor at different time instants during the contact process (i.e., the liquid discharge process) of the forming platform and the polymerizable liquid are obtained, and based on the distance change amount between the distance values corresponding to two adjacent time instants, the distance change rate of the forming platform is obtained by dividing the time interval between the two adjacent time instants, which is used to indicate the distance change of the forming platform and the build surface per unit time, i.e., the distance fluctuation between the forming platform and the build surface per unit time. The distance change rate can be used to determine whether the liquid discharge and backflow of the polymerizable liquid (such as liquid numerical value) are completed. When the distance change rate is less than (or equal to) the corresponding preset change rate threshold, it is considered that the liquid discharge tends to be stable, the liquid layer thickness is stable, and it is determined that the waiting time is sufficient, and the next printing process, such as the exposure process of the next slice layer, is performed.

[0067] Optionally, the distance change amount of the forming platform can also be used to determine whether the polymerizable liquid (such as liquid level) is completed. When the distance change amount is less than (or equal to) the corresponding preset distance threshold, it is considered that the liquid discharge tends to be stable, the liquid layer thickness is stable, and the waiting time is sufficient, and the next printing process is performed, such as the exposure process of the next slice layer. The preset distance threshold can be a preset distance threshold matched with the current printing layer determined from the process database.

[0068] It should be noted that the distance value between the forming platform and the construction surface is collected in real time by the displacement sensor, which can accurately monitor the distance change amount between the forming platform and the construction surface, thereby determining whether the liquid layer thickness tends to be stable, which helps to timely detect abnormal changes in the liquid layer thickness and avoid printing quality problems caused by unstable liquid layer thickness. By collecting the distance value between the forming platform and the construction surface by the displacement sensor and calculating the distance change, the liquid layer thickness change can be monitored in real time, and whether the liquid layer thickness tends to be stable can be determined in a timely and accurate manner, thereby reducing the printing time and improving the printing efficiency, printing accuracy and stability.

[0069] As an optional embodiment, the detection assembly includes a flow rate sensor, and the controller is configured to: acquire the liquid flow rate detected by the flow rate sensor, wherein the flow rate sensor is configured to collect the liquid flow rate at the bottom of the tray during the contact of the forming platform with the polymerizable liquid; and determine that the liquid layer thickness tends to be stable when the liquid flow rate is less than or equal to a preset speed threshold.

[0070] Optionally, during the contact of the forming platform with the polymerizable liquid, the resin flow rate at the bottom of the tray changes greatly, which can represent the liquid discharge process. Therefore, the flow rate sensor can be arranged at the position of the construction surface (mold at the bottom of the tray) to detect the flow rate (i.e. liquid flow rate) of the polymerizable liquid at the construction surface at the bottom of the tray during the contact of the forming platform with the polymerizable liquid (i.e. liquid discharge process). Since there is a certain relationship between the liquid flow rate and the liquid layer thickness. When the liquid flow rate gradually tends to be stable, it indicates that the flow state of the polymerizable liquid in the tray has reached a certain balance, and the liquid layer thickness also tends to be stable. Therefore, by monitoring the change of the liquid flow rate, whether the liquid layer thickness tends to be stable can be indirectly determined. During the liquid discharge process, when the flow rate of the polymerizable liquid is less than or equal to the preset speed threshold, it is considered that the liquid discharge tends to be stable, the liquid layer thickness is stable, and the waiting time is sufficient, and the next printing process is performed, such as the exposure process of the next slice layer. In the above manner, the liquid flow rate collected in real time by the flow rate sensor can monitor the liquid flow rate change at the bottom of the tray in real time, and whether the liquid layer thickness tends to be stable can be determined in a timely manner. Further, the downtime during the printing process can be reduced, the printing efficiency, printing accuracy and stability are improved.

[0071] As an optional embodiment, the detection component comprises an ultrasonic sensor or a laser radar sensor, and the controller is configured to: acquire the liquid level height in the tray detected by the ultrasonic sensor or the laser radar sensor, wherein the ultrasonic sensor or the laser radar sensor is configured to collect the liquid level height in the tray during the contact of the forming platform with the polymerizable liquid; and determine whether the liquid layer thickness tends to be stable according to the liquid level height.

[0072] Optionally, since the liquid level height directly reflects the amount of polymerizable liquid in the tray, and the liquid layer thickness can reflect the distribution of polymerizable liquid on the current printing layer in the actual printing process. By collecting the liquid level height in the tray in the contact process of the forming platform with the polymerizable liquid (i.e., the liquid discharge process) through the ultrasonic sensor or the laser radar sensor, the remaining and supply state of the polymerizable liquid in the tray can be known in time. By monitoring the change of the liquid level height in real time, the consumption speed and supply stability of the polymerizable liquid can be determined, and then it is determined whether the liquid layer thickness tends to be stable. When the polymerizable liquid remains relatively stable for a period of time, it is indicated that the supply of the liquid material is stable, so that the liquid layer thickness can be accurately inferred to be stable in time, and then it is determined that the waiting time is sufficient, and the next printing process is performed, such as the exposure process of the next slice layer.

[0073] Optionally, the ultrasonic sensor or the laser radar sensor can be installed on the side wall of the tray, or the ultrasonic sensor or the laser radar sensor can be arranged above the tray through a mounting bracket and emit light / waves toward the tray to detect the liquid level height in the tray. During the contact of the forming platform with the polymerizable liquid, the resin in the tray flows outward under the pressure of the forming platform, and the change of the liquid level height around the tray with time can be obtained through the ultrasonic sensor or the laser radar sensor, and whether the liquid layer thickness tends to be stable is determined according to the change of the liquid level height.

[0074] As an optional embodiment, determining whether the liquid layer thickness tends to be stable according to the liquid level height comprises: performing difference operation on the liquid level heights corresponding to two adjacent time points respectively to obtain a liquid level difference; calculating a time interval between the two adjacent time points; performing division operation on the liquid level difference and the time interval to obtain a liquid level height change rate of the tray; determining whether the liquid level height change rate is less than or equal to a preset height change rate; and determining that the liquid layer thickness tends to be stable in the case that the liquid level height change rate is less than or equal to the preset height change rate.

[0075] Optionally, in the process of determining whether the liquid layer thickness tends to be stable according to the change of the tray liquid level height, the change of the liquid level height around the tray over time can be obtained by the ultrasonic sensor or the laser radar sensor, and the liquid level height change rate is calculated. When the liquid level height change rate is less than or equal to the preset height change rate, it is considered that the liquid discharge tends to be stable at this time, the liquid layer thickness is stable, and it is determined that the waiting time is sufficient, and the next slice layer printing process is performed.

[0076] Specifically, in the printing process of each slice model, when the descending motion of the current layer corresponding to the forming platform is performed, a plurality of liquid level heights in the tray collected by the ultrasonic sensor or the laser radar sensor at different time points during the contact of the forming platform with the polymerizable liquid are obtained. The liquid level difference between the liquid level heights corresponding to two adjacent time points is divided by the time interval between the two adjacent time points to obtain the liquid level height change rate in the tray. Whether the polymerizable liquid is discharged and backflowed is determined according to the liquid level height change rate. When the liquid level height change rate is less than or equal to the preset height change rate, it is considered that the liquid discharge tends to be stable, the liquid layer thickness is stable, and it is determined that the waiting time is sufficient, and the next printing process is performed, such as the exposure process of the next slice layer.

[0077] As an optional embodiment, determining whether the liquid layer thickness tends to be stable according to the liquid level height comprises: determining whether the liquid level height continuously tends to be stable within a preset height threshold range; and determining that the liquid layer thickness tends to be stable when the liquid level height continuously stays within the preset height threshold range for a preset time.

[0078] Optionally, the currently collected liquid level height can be one or more of the liquid level heights of the tray at different time points. When the currently collected liquid level height is one, the liquid layer thickness can be determined to tend to be stable when the one liquid level height is within the preset liquid level height threshold range, wherein the one liquid level height is the latest collected liquid level height among the plurality of liquid level heights. In order to avoid inaccurate determination of whether the liquid layer thickness tends to be stable due to the mutation or accident of a single liquid level height, the currently collected liquid level height can be set to be a plurality of liquid level heights. At this time, the liquid layer thickness can be determined to tend to be stable when all the plurality of liquid level heights are within the preset liquid level height threshold range, or the liquid layer thickness can be determined to tend to be stable when the average of the plurality of liquid level heights is within the preset liquid level height threshold range. Thus, whether the current liquid layer thickness tends to be stable can be determined in time and accurately.

[0079] As an optional embodiment, the detection component comprises a photoelectric sensor or a strain gauge sensor, and the controller is configured to: acquire a deformation amount of the build surface detected by the photoelectric sensor or the strain gauge sensor, wherein the photoelectric sensor or the strain gauge sensor is configured to collect the deformation amount of the build surface during the contact of the forming platform with the polymerizable liquid; and determine that the liquid layer thickness tends to be stable when the deformation amount is less than or equal to a preset deformation amount threshold.

[0080] Optionally, the deformation amount of the build surface refers to the change in the shape of the build surface of the tray due to the solidification, shrinkage or external factors (such as temperature, humidity, etc.) of the polymerizable liquid during the 3D printing process, which can be collected by the photoelectric sensor or the strain gauge sensor. The liquid layer thickness can reflect the distribution of the polymerizable liquid on the current printing layer during the actual printing process. When the liquid layer thickness is unstable, it may cause the printed product to have uneven surface, size deviation and other problems. When the deformation amount of the build surface is large, it means that the build surface has large fluctuations or is uneven. The polymerizable liquid laid on the build surface will cause the liquid layer thickness to be uneven due to the uneven build surface, thereby affecting the printing quality. Conversely, when the deformation amount of the build surface is small, it means that the build surface is relatively flat, and the polymerizable liquid can form a relatively uniform liquid layer when laid, thereby ensuring the stability of the liquid layer thickness.

[0081] Based on this, by collecting the deformation amount of the build surface on the tray in real time by the photoelectric sensor or the strain gauge sensor during the contact of the forming platform with the polymerizable liquid (i.e. the liquid discharge process), the distribution and solidification of the polymerizable liquid corresponding to the current printing layer during the printing process can be understood in time. When the deformation amount remains relatively stable, i.e. the deformation amount is less than or equal to a preset deformation amount threshold, it indicates that the distribution and solidification of the polymerizable liquid corresponding to the current printing layer are relatively uniform, and it can be inferred that the liquid layer thickness also tends to be stable. Therefore, the liquid layer thickness can be inferred to be stable in time, and it is determined that the waiting time is sufficient, and the next printing process, such as the exposure process of the next slice layer, is performed.

[0082] It should be noted that during the contact of the forming platform with the polymerizable liquid, the forming platform is pressed down, and the resin in the tray flows to the periphery. The build surface (release film) at the bottom of the tray will have a certain deformation amount. The real-time deformation amount of the build surface at the bottom of the tray is acquired by the photoelectric sensor or the strain gauge sensor. When the deformation amount is greater than or equal to a preset deformation amount threshold, it is considered that the liquid discharge tends to be stable, the liquid layer thickness is stable, and it is determined that the waiting time is sufficient, and the next slice layer printing process is performed.

[0083] Optionally, photoelectric sensors (infrared sensors) can be arranged at the bottom of the tray (for example, at the middle of both sides of the bottom), one side emitting an optical signal and the other side receiving the optical signal. When the release film of the tray deforms, the optical signal emitted by the optical sensor will be blocked by the release film, and vice versa, when the release film does not exceed the position where the optical sensor is arranged, the optical signal will not be blocked by the release film. Therefore, the deformation of the release film of the tray can be determined according to the optical signal of the optical sensor, and then the waiting time and the movement of the forming platform can be adjusted. Strain gauge sensors can be arranged on the side of the tray to sense the deformation of the release film.

[0084] As an optional embodiment, the controller is further configured to: obtain a waiting time period between a starting time when the forming platform moves to the preset position and a time when it is determined that the liquid layer thickness tends to be stable; detect whether the waiting time period is greater than a preset waiting time period; and issue an exposure instruction to the optical module in the case where the waiting time period is greater than or equal to the preset waiting time period.

[0085] Optionally, from the start of the movement of the forming platform to the preset position to the process of the forming platform contacting the polymerizable liquid, that is, the liquid discharge process, the time period between the starting time when the forming platform moves to the preset position and the time when it is determined that the liquid layer thickness tends to be stable is determined as the waiting time t in the liquid discharge process. The waiting time t is compared with the preset waiting time period t0. If t is greater than t0, it is determined that the liquid layer thickness has stabilized, and the exposure of the next slice layer is entered. If t is less than t0, the waiting continues until t0. The preset waiting time period t0 can be understood as a safety waiting time period. The preset waiting time period can be obtained by querying a process database or can be set artificially.

[0086] It should be noted that in the pull-up 3D printing scenario, the single-layer printing process is: exposure → peeling → lowering → waiting. The waiting time before exposure in the pull-up 3D printing is that after the printing platform is lowered to contact the resin, a liquid discharge force is generated, which causes the forming platform and the tray to deform. A certain waiting time period is set as a preset waiting time period before the exposure of the next slice layer. This preset waiting time period allows the polymerizable liquid to flow appropriately before exposure, so as to ensure that the stable liquid layer thickness is maintained after the deformation is recovered, so as to ensure the quality and precision of printing. The setting of the preset waiting time period usually depends on the type of polymerizable liquid used (such as the type of resin), the printing area, the printing layer thickness, the properties of the printer and other factors.

[0087] Optionally, since the printing characteristics (such as printing difficulty, printing size, etc.) of each slice layer are different, the determination of the preset waiting time can be targeted according to the characteristics of each slice layer. For example, for a slice layer with complex structure and / or large coverage area, a longer preset waiting time can be set; for a slice layer with simple structure and / or small coverage area, a shorter preset waiting time can be set. In this way, not only can the polymerizable liquid form a relatively uniform liquid layer during laying, ensuring the stability of the liquid layer thickness and the printing accuracy, but also the waiting time before exposure can be reduced, improving the printing efficiency.

[0088] Optionally, for the printing process of a complex model with varying cross-section, the determination of whether the current liquid layer thickness tends to be stable and the determination of the waiting time can be performed simultaneously. Taking a force sensor as an example, first, it is detected whether the rate of change of the liquid discharge force is less than the corresponding preset change rate threshold, and then the waiting time is compared with the preset waiting time obtained from the process database until the waiting time reaches the preset waiting time. The above two conditions are met to determine the adaptive waiting time, which improves the printing stability and printing accuracy of complex models. For a simple model with varying cross-section, the waiting can be ended directly after detecting that the current liquid layer thickness tends to be stable and entering the exposure process of the next slice layer. For any slice layer, whether it belongs to a simple model or a complex model can be preset. Through the above distinction, the printing efficiency can be improved, and the polymerizable liquid can form a relatively uniform liquid layer during laying of each slice layer.

[0089] As an optional embodiment, the controller is further configured to, in the case that the waiting time is less than the preset waiting time, control the forming platform to continue waiting until the waiting time is greater than or equal to the preset waiting time, or slow down the movement speed of the forming platform until the waiting time is greater than or equal to the preset waiting time.

[0090] Optionally, the preset waiting time can be understood as a safety waiting time, that is, the shortest time that allows the polymerizable liquid to form a relatively uniform liquid layer during laying. If the waiting time does not reach the preset waiting time, the waiting continues until the preset waiting time is reached, thereby ensuring that the polymerizable liquid can form a relatively uniform liquid layer during laying, ensuring the stability of the liquid layer thickness and the printing accuracy.

[0091] As an optional embodiment, the controller is further configured to, during the printing of the three-dimensional object, detect whether the current printing layer is the first group of slice layers of the three-dimensional object; in the case that the current printing layer is not the first group of slice layers, control the detection component to obtain the liquid change state caused by the movement of the forming platform.

[0092] Optionally, in the process of printing the three-dimensional object, it is detected whether the current printing layer is a first set of slice layers of the three-dimensional object, the first set of slice layers representing a bottom layer of the three-dimensional object, and the bottom layer can be a first layer or a plurality of previous layers, such as a first layer or a first to tenth layer. If yes, no adaptive waiting is performed, and a slice layer exposure process is directly entered; if no, adaptive waiting is needed, and the controller controls the detection assembly to collect the liquid change state obtained by the forming platform movement. In other words, to ensure the forming quality of the bottom layer and avoid the falling of the bottom layer in the printing process, the bottom layer does not perform adaptive waiting.

[0093] As an optional embodiment, in the process of printing the three-dimensional object, the controller is further configured to: acquire a material type corresponding to the polymerizable liquid, and an actual waiting time of each slice layer corresponding to the three-dimensional object; wherein the actual waiting time is a waiting time of the forming platform before printing of each slice layer; and generate a printing parameter data packet according to the three-dimensional object, the material type corresponding to the polymerizable liquid, and the actual waiting time.

[0094] Optionally, the actual waiting time of each slice layer corresponding to the printing product (i.e., the three-dimensional object) and the printing material in the entire printing process is recorded; and a printing parameter data packet is generated according to the three-dimensional object, the material type corresponding to the polymerizable liquid, and the actual waiting time, and the process data packet is directly called when printing the same type of printing product next time. The process data packet can also include exposure parameters (exposure time) and stripping parameters.

[0095] Optionally, the exposure parameters corresponding to the three-dimensional object can be acquired in the following manner, but are not limited thereto: a test model corresponding to the three-dimensional object is sliced to obtain a slice data; when printing each slice layer, different area models in the slice data are printed according to different exposure times to obtain entity models printed at different exposure times, for example, a plurality of (such as four) different exposure time parameters can be selected to obtain a plurality of entity models; a model with the best printing quality is selected from the entity models, and the exposure time corresponding to the model with the best printing quality is determined as the exposure parameter; and the recorded exposure parameter is generated into a printing process data packet, and the process data packet is directly called when printing next time.

[0096] According to the embodiment of the present application, a method for forming a three-dimensional object is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0097] The method embodiment provided in Embodiment 1 of this application can be executed on a mobile terminal, computer terminal, or similar computing device. Figure 2 A hardware block diagram of a computer terminal for a method of forming three-dimensional objects is shown. Figure 2 As shown, the computer terminal 10 may include one or more processors (shown as 102a, 102b, ..., 102n in the figure) (the processor may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of a BUS bus), a network interface, a power supply, and / or a camera. Those skilled in the art will understand that... Figure 2 The structure shown is for illustrative purposes only and does not limit the structure of the aforementioned electronic device. For example, computer terminal 10 may also include... Figure 2 The more or fewer components shown, or having the same Figure 2 The different configurations shown.

[0098] It should be noted that the aforementioned one or more processors and / or other data processing circuits are generally referred to herein as "data processing circuits". These data processing circuits may be implemented wholly or partially as software, hardware, firmware, or any other combination thereof. Furthermore, the data processing circuits may be a single, independent processing module, or may be wholly or partially integrated into any other element in the computer terminal 10. As involved in the embodiments of this application, the data processing circuits serve as processor control (e.g., selection of a variable resistor termination path connected to an interface).

[0099] The memory 104 can be used to store software programs and modules of application software, such as the program instructions / data storage device corresponding to the method for forming a three-dimensional object in the embodiments of the present invention. The processor executes various functional applications and data processing by running the software programs and modules stored in the memory 104, that is, implementing the method for forming a three-dimensional object of the aforementioned application. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor, and these remote memories can be connected to the computer terminal 10 via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0100] The display can be a touch screen liquid crystal display (LCD) that enables a user to interact with the user interface of the computer terminal 10.

[0101] Figure 3 is a flowchart of a method for forming a three-dimensional object according to an embodiment of the present application, as shown in Figure 3 The method is implemented by a three-dimensional printing device, which includes a forming platform on which the three-dimensional object is formed, a tray having a build surface, a printing area for filling a polymerizable liquid being formed between the forming platform and the build surface, and an optical module for irradiating the printing area to form a solid or semi-solid polymer from the polymerizable liquid. The method comprises:

[0102] In step S202, the forming platform is controlled to move so as to be in contact with the polymerizable liquid.

[0103] In step S204, a liquid change state during the contact of the forming platform with the polymerizable liquid is acquired.

[0104] In step S206, it is determined whether the liquid layer thickness tends to be stable according to the liquid change state, and an exposure instruction is sent to the optical module to irradiate the printing area when it is determined that the liquid layer thickness tends to be stable.

[0105] In the embodiment of the present application, the liquid change state during the contact of the forming platform with the polymerizable liquid is detected in real time by the detection assembly, and it is quickly and accurately determined whether the liquid layer thickness tends to be stable based on the liquid change state, so as to accurately determine whether to end the pre-exposure waiting, thereby improving the accuracy and applicability of the pre-exposure waiting setting of 3D printing, avoiding the problems of voids or uneven printing layer thickness, improving the efficiency and stability of 3D printing, and further solving the technical problems of poor applicability of the pre-exposure waiting time and easy occurrence of voids or uneven printing layer thickness caused by determining whether to end the pre-exposure waiting and enter the exposure phase based on experience values in the related art.

[0106] Based on the above embodiments and optional embodiments, an optional implementation of the present application is provided, Figure 4 is a flowchart of an optional method for forming a three-dimensional object according to an embodiment of the present application, as shown in Figure 4 The method is a method for forming a three-dimensional object in the case that the detection assembly is a force sensor, and the method comprises:

[0107] In S11, during the printing of each layer of the slice model, when the descending movement of the forming platform corresponding to the current printing layer is started, the forming platform is lowered to a specified position according to the process package parameters.

[0108] S12, according to the printing slice data, it is judged whether the current printing layer is the first group of slice layers, that is, whether it is the bottom layer, if so, no adaptive waiting is performed; otherwise, adaptive waiting is performed, and step S13 is entered.

[0109] S13, the force values of the molding platform at different times in the process of contacting the molding platform with the polymerizable liquid (i.e. the liquid discharge process) are collected in real time by the force sensor, and the controller calculates the force value change between the force values corresponding to two adjacent times, wherein the force sensor can be installed on the molding platform structure or the bottom structure of the exposure device (tray), and the force sensor can measure multiple force values at different times. Then, the force value change is divided by the time interval between the two adjacent times to obtain the force value change rate. The formula can be expressed as: force value change rate = (Δ force value) / (Δ time). Based on the force values collected at different times, the above method is used to calculate the liquid discharge force change rate in real time.

[0110] S14, it is judged in real time whether the force value change rate is less than a certain threshold value within a certain time, that is, whether the force value change rate is within the preset force value threshold range, if so, it is determined that the liquid layer thickness has stabilized, and then the exposure of the next slice layer is directly entered. If not, continue to wait and collect the force value of the molding platform by the force sensor.

[0111] It should be noted that in the pull-up 3D printing scene, the 3D printing process is briefly described as exposure → stripping → lowering → waiting (next slice layer), when the molding platform moves to the specified position according to the process package parameters and stops, the polymerizable liquid (such as liquid resin) is squeezed and discharged out of the plane during the lowering process of the molding platform until the liquid layer thickness stabilizes, and the liquid discharge force value and the force value feedback of the platform are changing all the time during this process.

[0112] The force value of the molding platform can also be understood as the liquid discharge force, and the corresponding force value change rate can be understood as the liquid discharge force change rate. The liquid discharge force is an important physical effect in the process of photocuring printing. In the process of photocuring printing, the polymerizable liquid is injected into the tank, and the printing platform is gradually pressed down, so that the polymerizable liquid is subjected to pressure and begins to discharge to the edge of the molding platform. During this process, the polymerizable liquid will generate a reaction force on the molding platform, which is called the liquid discharge force (hereinafter referred to as the liquid discharge force). The size of the liquid discharge force is related to the speed of the molding platform, the fluidity of the resin, the geometry of the tank, the consistency of the equipment, the environment, etc. The liquid discharge force value change rate during the waiting process can be obtained by monitoring the force sensor arranged at the corresponding position (such as the top) of the molding platform in real time, to judge whether the liquid layer thickness is stable. If it is detected that the liquid layer thickness has stabilized, the exposure of the next slice layer is directly entered, so as to save the printing time, improve the printing efficiency, and improve the precision and quality of the printed parts.

[0113] Based on the above embodiments and optional embodiments, the present application proposes an optional implementation, Figure 5 is a flow chart of an optional method for forming a three-dimensional object according to an embodiment of the present application, as shown in Figure 5 , which is also a method for forming a three-dimensional object in the case where the detection component is a force sensor, the method comprising:

[0114] S21, during the printing of each layer of the slice model, when starting the descending movement of the forming platform corresponding to the current printing layer, the forming platform is lowered to a specified position according to the process package parameters.

[0115] S22, according to the printing slice data, it is judged whether the current printing layer is the first group of slice layers, i.e. whether it is the bottom layer, if so, no adaptive waiting is performed; otherwise, adaptive waiting is performed, and step S13 is entered.

[0116] S23, the force sensor is used to collect the force value of the forming platform at different times during the process of the forming platform contacting the polymerizable liquid (i.e. the liquid discharge process), and the current collected force value is obtained.

[0117] S24, the current collected force value is compared with the preset force value threshold range corresponding to the current printing layer, and the preset force value threshold range is the preset force value threshold range corresponding to the current printing layer in the process database. When it is detected that the current collected force value is between the preset threshold range [a, b], it is determined that the liquid layer thickness is stable, and the exposure of the next slice layer is entered.

[0118] Based on the above embodiments and optional embodiments, the present application proposes an optional implementation, Figure 6 is a flow chart of another optional method for forming a three-dimensional object according to an embodiment of the present application, as shown in Figure 6 , which is also a method for forming a three-dimensional object in the case where the detection component is a force sensor, the method comprising:

[0119] S31, during the printing of each layer of the slice model, when starting the descending movement of the forming platform corresponding to the current printing layer, the forming platform is lowered to a specified position according to the process package parameters.

[0120] S32, according to the printing slice data, it is judged whether the current printing layer is the first group of slice layers, i.e. whether it is the bottom layer, if so, no adaptive waiting is performed; otherwise, adaptive waiting is performed, and step S3 is entered.

[0121] S33, the force sensor is used to collect the force value of the forming platform at different time points during the process of the forming platform contacting with the polymerizable liquid (i.e. the liquid discharge process), and the controller calculates the force value change between the force values corresponding to two adjacent time points. Then, the force value change is divided by the time interval between the two adjacent time points, and the force value change rate is obtained. The formula can be expressed as: force value change rate = (Δ force value) / (Δ time). Based on the force values collected at different time points, the above method is used to calculate the liquid discharge force change rate in real time.

[0122] S34, it is judged whether the liquid discharge force change rate is less than a certain threshold value within a certain time, if yes, the forming platform position is kept, and the waiting time t is compared with the preset waiting time t0 in the process database, if t is greater than or equal to t0, it is judged that the liquid layer thickness has been stabilized, and the exposure of the next slice layer is entered. If t is less than t0, the waiting continues.

[0123] Further, the preset waiting time t0 is obtained by querying the process database, and can be set artificially. In the pull-up 3D printing scene, the single layer printing process is: exposure → stripping → lowering → waiting. After the printing platform is lowered to contact the resin, the platform assembly and the tray will be deformed due to the liquid discharge force, and a certain waiting time is set as the preset waiting time before the exposure of the next slice layer. This preset waiting time allows the liquid resin to flow properly before exposure, so as to ensure that the deformation is recovered and the stable liquid layer thickness is maintained, so as to ensure the quality and precision of printing. The setting of the preset waiting time usually depends on the type of resin used, the printing area, the printing layer thickness, the properties of the printer, etc.

[0124] Further, the parameter for determining the preset waiting time in the process database can be the printing complexity. For example, for the printing process of a complex model with varying cross sections, the liquid discharge force value detected by the detection sensor and the preset waiting time t0 in the process database are compared at the same time. First, it is judged whether the liquid discharge force change rate is less than the corresponding preset change rate threshold value, and then the waiting time is compared with the preset waiting time t0 obtained from the process database until the waiting time reaches the preset waiting time t0. If the above conditions are met, the adaptive waiting time can be determined, which improves the printing stability and precision of complex models.

[0125] It should be noted that the above Figures 4 to 6 embodiments are only the processing flow when the detection assembly is a force sensor. For the processing flow of the detection assembly being a displacement sensor, a flow rate sensor, an ultrasonic sensor, a laser radar sensor, a photoelectric sensor, a strain gauge sensor, etc., the specific processing mode is consistent with the processing flow when the detection assembly is a force sensor, and the only difference is that the detected operating parameters (or liquid change state) during the process of the forming platform contacting with the polymerizable liquid and the judgment condition of whether the liquid layer thickness tends to be stable are different, which will not be described here.

[0126] The above embodiments can achieve the following effects: 1) According to the value of the sensor, the liquid change state during the liquid discharge process is updated in real time, and when the liquid change state meets the preset condition, it can quickly and accurately determine whether the liquid layer thickness of the current layer slice model is stable, thereby improving the efficiency and stability of 3D printing. The adaptive determination of the pre-exposure waiting time can improve the consistency and stability of the printing process. According to different printing models and different viscosity resins at different fluid discharge rates, the pre-exposure waiting time is automatically adjusted to achieve higher printing precision and efficiency. 2) For printing models with complex cross-section changes, the liquid layer thickness is accurately determined by real-time detection of the discharge force change rate, thereby reducing the layer thickness error and improving the printing surface quality. 3) The printing process is optimized by using model slicing, real-time force value change and equipment state monitoring to achieve better liquid discharge behavior and implement real-time adjustment of the waiting time, thereby improving the printing quality. 4) The printing time is shortened, the printing surface quality and printing precision are improved, and the user has a better experience.

[0127] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited to the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0128] Through the above description of the embodiments, those skilled in the art can clearly understand that the method for forming a three-dimensional object according to the above embodiments can be realized by means of software and the necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes a plurality of instructions for causing a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the method of each embodiment of the present application.

[0129] Those skilled in the art can understand that all or part of the steps of the various methods of the above embodiments can be completed by programs instructing the relevant hardware of the terminal device, and the programs can be stored in a non-volatile storage medium, which can include a flash disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc.

[0130] The embodiment of the present application also provides a non-volatile storage medium. Optionally, in the embodiment, the non-volatile storage medium can be used to save the program code executed by the method for forming a three-dimensional object provided by the above embodiment.

[0131] Optionally, in the embodiment, the non-volatile storage medium can be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the mobile terminals in a mobile terminal group.

[0132] Optionally, in the embodiment, the non-volatile storage medium is configured to store program code for performing the following steps: controlling the forming platform to move away from the construction surface or to reciprocate relative to the construction surface to form a three-dimensional object from the solid or semi-solid polymer, and: obtaining the changing state of the solid or semi-solid polymer detected by the detection assembly during the separation of the solid or semi-solid polymer from the construction surface; and controlling the movement of the forming platform according to the changing state.

[0133] The serial numbers of the above embodiments of the present application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0134] In the above embodiments of the present application, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the related description of other embodiments.

[0135] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented by other ways. Among them, the above-described device embodiments are only schematic, for example, the division of the units can be a logical function division, and actual implementation can have another division way, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the displayed or discussed each other can be through some interface, indirect coupling or communication connection between units or modules, which can be electrical or other forms.

[0136] The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed to multiple units. Part or all of the units can be selected according to actual needs to achieve the purpose of the embodiment.

[0137] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The above integrated unit can be realized in the form of hardware or software functional unit.

[0138] The integrated unit, if implemented in the form of a software function unit and sold or used as an independent product, can be stored in a nonvolatile storage medium. Based on such understanding, the technical solutions of the present application, essentially or in other words, the part that contributes to the prior art or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, including a plurality of instructions to make a computer device (which can be a personal computer, a server or a network device, etc.) execute all or part of the steps of the method described in various embodiments of the present application. The aforementioned storage medium includes: a U disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0139] The above is only the preferred embodiment of the present application, it should be pointed out that, for those skilled in the art, without departing from the principles of the present application, can make a number of improvements and refinements, these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. An apparatus for forming a three-dimensional object, the apparatus comprising: include: A molding platform on which a three-dimensional object is formed; A material tray having a structured surface, with a printing area for filling polymerizable liquid formed between the molding platform and the structured surface; An optical module is used to illuminate the printed area to form a solid or semi-solid polymer from the polymerizable liquid; A controller is configured to connect to the molding platform for controlling the movement of the molding platform during printing to bring the molding platform into contact with the polymerizable liquid; A detection component is used to acquire the liquid change state during the contact process between the molding platform and the polymerizable liquid; The controller is configured to communicate with the detection component and the optical module, and is used to determine whether the liquid layer thickness tends to be stable based on the liquid change state, and to issue an exposure command to the optical module to irradiate the printing area when it is determined that the liquid layer thickness tends to be stable; The controller is further configured to: acquire the time elapsed between the start time of the molding platform moving to a preset position and the time when the liquid layer thickness is determined to be stable, thereby obtaining a waiting time; and detect whether the waiting time is greater than a preset waiting time. If the waiting time is greater than or equal to the preset waiting time, the exposure command is sent to the optical module. The preset waiting time is used for the predetermined slice layer and is determined according to the printing characteristics of the predetermined slice layer. The printing characteristics include at least one of the following: the coverage area of ​​the predetermined slice layer, the printing width, the printing layer thickness, and the type of polymerizable liquid used in the predetermined slice layer.

2. The apparatus of claim 1, wherein, The controller is also configured to: When it is determined that the thickness of the liquid layer has not stabilized, the forming platform is controlled to wait, or the waiting time of the forming platform is adjusted, or the movement speed of the forming platform is adjusted.

3. The apparatus of claim 1, wherein, The detection components include one or more of the following: force sensor, displacement sensor, flow velocity sensor, ultrasonic sensor, lidar sensor, photoelectric sensor, and strain gauge sensor; The liquid change state is obtained from one or more of the following: force value, displacement change, liquid flow rate, liquid level height, and material tray deformation.

4. The device according to claim 1, characterized in that, The detection component includes a force sensor, and the controller is configured to: The force sensor detects multiple force values ​​that the molding platform experiences at different times, wherein the force sensor is configured to acquire the force values ​​applied to the molding platform during the process of the molding platform contacting the polymerizable liquid. The thickness of the liquid layer is determined based on the multiple force values ​​to determine whether it tends to stabilize.

5. The device according to claim 4, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the plurality of force values ​​includes: The difference between the force values ​​experienced by the forming platform at two adjacent moments is calculated to obtain the change in force value; Calculate the time interval between the two adjacent moments; The rate of change of force is obtained by dividing the change in force by the time interval. Determine whether the rate of change of the force value is less than a preset rate of change threshold; When the rate of change of the force value is less than the preset rate of change threshold, the thickness of the liquid layer is determined to be stable.

6. The device according to claim 4, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the multiple force values ​​includes: Determine whether the currently collected force value is within the preset force value threshold range; If the currently collected force value is within the preset force value threshold range, the thickness of the liquid layer is determined to be stable.

7. The device according to claim 1, characterized in that, The detection component includes a displacement sensor, and the controller is configured to: Multiple distance values ​​detected by the displacement sensor are acquired, wherein the displacement sensor is configured to be disposed on the molding platform and to collect the distance value between the molding platform and the structure surface; The liquid layer thickness is determined based on the multiple distance values ​​to determine whether it tends to stabilize.

8. The device according to claim 7, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the plurality of distance values ​​includes: Determine whether the currently collected distance value is within the preset distance threshold range; If the currently collected distance value is within the preset distance threshold range, the thickness of the liquid layer is determined to be stable.

9. The device according to claim 7, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the plurality of distance values ​​includes: The distance change is obtained by performing a difference calculation on the distance values ​​between the forming platform and the structured surface at two adjacent time points. Calculate the time interval between the two adjacent moments; The distance change rate is obtained by dividing the distance change amount by the time interval. Determine whether the rate of change of distance is less than a preset rate of change threshold; When the rate of change of distance is less than the preset rate of change threshold, the thickness of the liquid layer is determined to be stable.

10. The device according to claim 1, characterized in that, The detection component includes a flow rate sensor, and the controller is configured to: The flow rate detected by the flow rate sensor is acquired, wherein the flow rate sensor is configured to collect the liquid flow rate at the bottom of the tray during the contact between the molding platform and the polymerizable liquid; When the liquid flow rate is less than or equal to a preset velocity threshold, the thickness of the liquid layer is determined to be stable.

11. The device according to claim 1, characterized in that, The detection component includes an ultrasonic sensor or a lidar sensor, and the controller is configured to: The liquid level height in the tray detected by an ultrasonic sensor or a lidar sensor is acquired, wherein the ultrasonic sensor or lidar sensor is configured to acquire the liquid level height in the tray during the contact between the molding platform and the polymerizable liquid. The liquid level height is used to determine whether the liquid layer thickness tends to stabilize.

12. The device according to claim 11, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the liquid level height includes: The difference between the liquid level heights at two adjacent times is calculated to obtain the liquid level difference. Calculate the time interval between the two adjacent moments; The liquid level difference and the time interval are divided to obtain the rate of change of the liquid level height in the tray; Determine whether the rate of change of liquid level height is less than or equal to a preset rate of change of height; When the rate of change of liquid level height is less than or equal to the preset rate of change of height, the thickness of the liquid layer is determined to be stable.

13. The device according to claim 11, characterized in that, The step of determining whether the liquid layer thickness tends to stabilize based on the liquid level height includes: Determine whether the liquid level height continues to stabilize within a preset height threshold range; If the liquid level remains within the preset height threshold range for a preset time, the thickness of the liquid layer is determined to tend to stabilize.

14. The device according to claim 1, characterized in that, The detection component includes a photoelectric sensor or a strain gauge sensor, and the controller is configured to: The deformation of the constructed surface detected by a photoelectric sensor or a strain gauge sensor is acquired, wherein the photoelectric sensor or strain gauge sensor is configured to acquire the deformation of the constructed surface during the contact between the molding platform and the polymerizable liquid. When the deformation is greater than or equal to a preset deformation threshold, the thickness of the liquid layer is determined to be stable.

15. The device according to claim 1, characterized in that, The controller is also configured to: If the waiting time is less than the preset waiting time, the molding platform is controlled to continue waiting until the waiting time is greater than or equal to the preset waiting time, or the movement speed of the molding platform is slowed down until the waiting time is greater than or equal to the preset waiting time.

16. The device according to claim 1, characterized in that, The controller is also configured to: During the printing process of the three-dimensional object, it is detected whether the current printing layer is the first set of slice layers of the three-dimensional object; If the current printing layer is not the first set of slice layers, the detection component is controlled to acquire the liquid change state obtained by the movement of the molding platform.

17. The device according to claim 1, characterized in that, During the printing process of the three-dimensional object, the controller is also configured to: Obtain the material type corresponding to the polymerizable liquid and the actual waiting time for each slice layer corresponding to the three-dimensional object; wherein, the actual waiting time is the waiting time of the molding platform before printing each slice layer; A printing parameter data package is generated based on the three-dimensional object, the material type corresponding to the polymerizable liquid, and the actual waiting time.

18. A method for forming a three-dimensional object, characterized in that, The process is achieved by a 3D printing device, which includes a forming platform on which a 3D object is formed; a material tray having a structured surface, and a printing area for filling a polymerizable liquid is formed between the forming platform and the structured surface. An optical module is used to illuminate the printed area to form a solid or semi-solid polymer from the polymerizable liquid; Detection components; The controller is configured to communicate with the molding platform, the detection component, and the optical module; the method includes: The molding platform is moved by a controller so that it comes into contact with the polymerizable liquid. The liquid change state during the contact process between the molding platform and the polymerizable liquid is obtained by the detection component; The controller is used to determine whether the liquid layer thickness tends to stabilize based on the liquid change state, and when it is determined that the liquid layer thickness tends to stabilize, it sends an exposure command to the optical module to make the optical module irradiate the printing area. The controller is used to acquire the time between the start time of the molding platform moving to the preset position and the time when the liquid layer thickness is determined to be stable, and obtain a waiting time; detect whether the waiting time is greater than a preset waiting time; if the waiting time is greater than or equal to the preset waiting time, issue the exposure command to the optical module; The preset waiting time is used for the predetermined slice layer and is determined according to the printing characteristics of the predetermined slice layer. The printing characteristics include at least one of the following: the coverage area of ​​the predetermined slice layer, the printing width, the printing layer thickness, and the type of polymerizable liquid used in the predetermined slice layer.

19. A non-volatile storage medium, characterized in that, The non-volatile storage medium stores multiple instructions adapted for loading by a processor and executing the method for forming a three-dimensional object as described in claim 18.

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