Control method of 3D printing equipment, 3D printing equipment and readable storage medium

Abstract

The invention provides a control method of 3D printing equipment, the 3D printing equipment and a readable storage medium, and relates to the technical field of 3D printing. The method comprises the steps that a printing platform of the 3D printing equipment is controlled to make a preset moving action in response to a preset instruction; a first detection value used for representing the stress condition of the printing platform in the moving process of the printing platform is obtained; when the first detection value is smaller than or equal to a first threshold value, the printing platform is continuously controlled to make a preset moving action, and a second detection value used for representing the stress condition of the printing platform is obtained in the continuous moving process of the printing platform; and according to the first detection value and / or the second detection value, the situation that the foreign matter exists in the 3D printing equipment is determined.

Description

Technical Field

[0001] The present application relates to the technical field of 3D printing, and in particular to a control method for a 3D printing device, a 3D printing device, and a readable storage medium. Background Art

[0002] During the operation of 3D printing equipment, the Z axis will be lowered to a specific height or reset to zero. If there are model residues or other foreign matter in the descending path of the printing platform, the exposure screen may be crushed during the descent of the printing platform, causing the equipment to be unable to be used normally. Summary of the invention

[0003] In view of this, the present application provides a control method for a 3D printing device, a 3D printing device, and a readable storage medium, which realize foreign body detection of the 3D printing device.

[0004] In a first aspect, an embodiment of the present application provides a method for controlling a 3D printing device, the method comprising:

[0005] Controlling the printing platform of the 3D printing device to perform a preset movement action in response to a preset instruction;

[0006] Acquire a first detection value used to characterize a force condition of the printing platform during movement of the printing platform;

[0007] When the first detection value is less than or equal to a first threshold, continuously controlling the printing platform to perform the preset movement action, and obtaining a second detection value for characterizing the force condition of the printing platform during the continuous movement of the printing platform;

[0008] The presence of foreign matter in the 3D printing device is determined according to the first detection value and / or the second detection value.

[0009] In a second aspect, an embodiment of the present application provides a 3D printing device, including:

[0010] A trough for containing resin;

[0011] A printing platform, used for carrying a printing model, wherein the printing platform moves relative to the material trough;

[0012] A memory storing programs or instructions;

[0013] A processor, wherein when the processor executes the program or instruction, the steps of the method according to the first aspect are implemented.

[0014] In a third aspect, an embodiment of the present application provides a readable storage medium, on which a program or instruction is stored, and when the program or instruction is executed by a processor, the steps of the method of the first aspect are implemented.

[0015] In the embodiment of the present application, in the process of controlling the printing platform to perform the preset moving action, the force on the printing platform is detected in real time, and the foreign matter is first judged according to the first detection value corresponding to when the printing platform starts to move, so as to quickly determine whether the printing platform has contacted the foreign matter at the moment of starting to move, and timely detection of the foreign matter is achieved. Furthermore, if the printing platform does not contact the foreign matter at the moment of starting to move, the detection is continued according to the acquired detection value, which can ensure that the foreign matter detection is achieved during the whole preset moving action, avoid the problems such as the exposure screen being crushed due to the presence of foreign matter in the moving route of the printing platform, and improve the service life of the 3D printing equipment.

[0016] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0018] Figure 1 One of the flow charts of the control method of the 3D printing device according to the embodiment of the present application is shown;

[0019] Figure 2 The second flowchart of the control method of the 3D printing device according to the embodiment of the present application is shown. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0021] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0022] The control method of the 3D printing device, the 3D printing device and the readable storage medium provided in the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0023] The present application embodiment provides a control method for a 3D printing device, such as Figure 1 As shown, the method includes:

[0024] Step 101, in response to a preset instruction, controlling a printing platform of a 3D printing device to perform a preset moving action.

[0025] In this step, a preset instruction is obtained, and the printing platform is controlled to perform a preset moving action based on the preset instruction. Subsequently, the 3D printing device is detected to see if there are foreign objects based on the preset moving action. The presence of foreign objects in the 3D printing device includes models or residues sticking to the lower surface of the printing platform, residues, broken models, foreign objects, etc. at the bottom of the material box.

[0026] The preset moving action includes controlling the printing platform to move a preset distance, move for a first preset time, or move to a preset position (eg, a zero point).

[0027] In one embodiment of the present application, controlling the printing platform to make a preset movement action in response to a preset instruction includes: controlling the printing platform to make a preset movement action toward or away from a material slot of a 3D printing device in response to the preset instruction.

[0028] In this embodiment, when the printing platform moves toward or away from the material box of the 3D printing device, it is possible to encounter foreign objects. Therefore, in response to a preset instruction, the printing platform is controlled to move toward or away from the material box to perform a preset movement. In one embodiment, the printing platform can be controlled to move toward or away from the material box, move a preset distance, move for a first preset time, or move to a preset position.

[0029] Therefore, when the printing platform moves toward the material box or moves away from the material box, it is possible to detect foreign matter in the 3D printing device.

[0030] In one embodiment of the present application, controlling the printing platform to perform a preset movement action in response to a preset instruction includes: controlling the printing platform to perform a preset movement action in response to a preset instruction to adjust the Z-axis height of the printing platform.

[0031] In this embodiment, the preset instruction may be a preset instruction for adjusting the Z-axis height of the printing platform, which may be to adjust the printing platform upward along the Z-axis (backwards from the material box), or to adjust the printing platform downward along the Z-axis (towards the material box). In one embodiment, the printing platform may be controlled to move a preset distance, a first preset time, or to a preset position along the Z-axis.

[0032] Therefore, the detection of foreign matter in the 3D printing device can be achieved in the scenario where the Z-axis height of the printing platform needs to be adjusted.

[0033] Step 102: Obtain a first detection value for characterizing a force condition of the printing platform during movement of the printing platform.

[0034] In this step, when the printing platform makes a preset moving action, the force condition of the printing platform is monitored in real time to obtain a first detection value for characterizing the force condition of the printing platform. Further, the obtained first detection value is compared with the first threshold value to detect whether there is a foreign object in the 3D printing device.

[0035] In one embodiment, a detection device is provided on the cantilever of the 3D printing device, and the detection device is used to detect the stress condition of the printing platform. The detection device can be a force detection device, a deformation detection device, etc., and can specifically be an elastic resistance strain gauge, a tension sensor, etc., which can detect the deformation amount at a specific position of a specific component and other physical quantities that can express its stress change, such as tension, gravity, pressure, torque, etc. When the detection device is provided on the cantilever of the 3D printing device, after the printing platform is mounted on the cantilever, the printing platform will produce a pulling effect on the cantilever, causing the cantilever to deform slightly. By measuring the deformation of the cantilever, the weight of the printing platform can be obtained. During the lifting process of the printing platform, the model gravity and the tension of the release film (i.e., the release force) received by the printing platform will also indirectly reflect the deformation of the cantilever. Therefore, the stress condition of the printing platform can be obtained through the detection device.

[0036] In one embodiment of the present application, obtaining a first detection value for characterizing the force condition of the printing platform during the movement of the printing platform includes: obtaining a first detection value for characterizing the force condition of the printing platform when the printing platform starts to move, or when the printing platform starts to move for a second preset time.

[0037] In this embodiment, the timing for obtaining the first detection value may be before the printing platform starts to move, when it starts to move, or when the printing platform starts to move for a second preset time, where the second preset time is a shorter time, such as 0.5s, 1s, 2s, etc. In other words, the first detection value can reflect the magnitude of the force applied to the printing platform when the printing platform starts to move, and then the 3D printing device can be detected for foreign matter based on the first detection value.

[0038] In an embodiment of the present application, when the printing platform starts to move, a first detection value representing the magnitude of the force applied to the printing platform at this time is monitored in real time, and the first detection value is then compared with a first threshold value, so as to quickly determine whether the printing platform has contacted a foreign object at the moment of starting to move, thereby achieving timely detection of the foreign object.

[0039] Step 103: when the first detection value is less than or equal to the first threshold, the printing platform is continuously controlled to perform a preset movement action, and a second detection value for characterizing the force condition of the printing platform is obtained during the continuous movement of the printing platform.

[0040] In this step, the magnitude relationship between the first detection value and the first threshold value is determined by comparing the first detection value with the first threshold value. If the first detection value is less than or equal to the first threshold value, it indicates that when the printing platform starts to move, the force on the printing platform is small, that is, no foreign matter is contacted at this time. In this case, the printing platform continues to be controlled to perform the preset movement action, and during the preset movement action continued by the printing platform, the force on the printing platform continues to be monitored in real time to obtain a second detection value for characterizing the force condition of the printing platform. The second detection value is obtained after the first detection value. For example, the control of the printing platform to perform the preset movement action is to control the printing platform to descend by 10mm, and the first detection value is obtained when the preset stroke is descended by 1mm. If the comparison shows that the first detection value is less than or equal to the first threshold value, it continues to descend by 9mm, and the second detection value is obtained during the process of descending by 9mm. That is to say, before the printing platform starts to move, at the moment of starting to move, or within the second preset time or preset stroke when the printing platform starts to move, the detection value obtained is the first detection value. By comparing the first detection value with the first threshold, if it is necessary to continuously control the printing platform to make a preset movement action, the detection value obtained is the second detection value, that is, the detection value obtained outside the second preset time period or preset stroke is the second detection value.

[0041] In one embodiment of the present application, comparing the first detection value with the first threshold includes: comparing the absolute value of the first detection value with the absolute value of the first threshold.

[0042] In this embodiment, comparing the first detection value with the first threshold value includes comparing the absolute value of the first detection value with the absolute value of the first threshold value.

[0043] When the detection value and threshold are positive numbers, when the first detection value is less than or equal to the first threshold, it indicates that the printing platform is subjected to less force; when the first detection value is greater than the first threshold, it indicates that the printing platform is subjected to greater force. When the detection value and threshold are negative numbers, when the first detection value is greater than or equal to the first threshold, that is, when the absolute value of the first detection value is less than or equal to the absolute value of the first threshold, it indicates that the printing platform is subjected to less force; when the first detection value is less than the first threshold, that is, when the absolute value of the first detection value is greater than the absolute value of the first threshold, it indicates that the printing platform is subjected to greater force.

[0044] In one embodiment of the present application, continuously controlling the printing platform to perform a preset movement action includes: confirming whether the printing platform has completed the preset movement action, and if the preset movement action has not been completed, continuing to move;

[0045] The method further includes: if the preset moving action has been completed, stopping the moving.

[0046] In this embodiment, when the printing platform is continuously controlled to perform a preset movement action, it is first determined whether the printing platform has completed the preset movement action. If the preset movement action has not been completed, the printing platform is continuously controlled to perform the preset movement action. If the preset movement action has been completed, the printing platform is controlled to stop moving. For example, the printing platform is controlled to descend by 10 mm, and a foreign object is detected when it descends to 10 mm. At this time, the printing platform has completed the preset movement action, and the printing platform is controlled to stop descending.

[0047] In the embodiment of the present application, foreign object detection is performed while the printing platform is executing a preset movement action until the preset movement action is completed, thereby realizing timely detection and identification of foreign objects on the path of the printing platform.

[0048] In one embodiment of the present application, a method for obtaining a first detection value and / or a second detection value includes: obtaining multiple detection values ​​for characterizing the force condition of the printing platform, and using the median value of the multiple detection values ​​as the first detection value and / or the second detection value.

[0049] In this embodiment, when obtaining the first detection value, multiple detection values ​​during the movement of the printing platform are obtained, and the median value of the multiple detection values ​​or other values ​​near the median value are used as the first detection value; when obtaining the second detection value, multiple detection values ​​during the movement of the printing platform are obtained, and the median value of the multiple detection values ​​or other values ​​near the median value are used as the second detection value. For example, for multiple detection values, they are arranged in order of size, and then the middle value is taken as the valid data for sampling, as the first detection value and / or the second detection value, so as to perform foreign matter detection. In the embodiment of the present application, the median value filtering method is used to filter out abnormal values ​​in the detection value data, effectively filtering out occasional abnormal values ​​of the detection device, and providing accurate data for subsequent foreign matter detection.

[0050] In one embodiment of the present application, obtaining a first detection value for characterizing a force condition of the printing platform during movement of the printing platform includes: obtaining a first detection value for characterizing a force condition of the printing platform at a first sampling frequency;

[0051] Acquiring a second detection value for characterizing the force condition of the printing platform during the continuous movement of the printing platform includes:

[0052] A second detection value for characterizing the force condition of the printing platform is obtained at a second sampling frequency, and the first sampling frequency is the same as or different from the second sampling frequency.

[0053] In this embodiment, during the movement of the printing platform, a first detection value is acquired at a first sampling frequency, and a second detection value is acquired at a second sampling frequency.

[0054] Among them, the first sampling frequency and the second sampling frequency can be the same. The same sampling frequency can ensure that the two detection values ​​are synchronized in time and can be directly compared, which helps to more accurately reflect the force conditions of the printing platform during movement, thereby improving the accuracy of foreign body detection.

[0055] The first sampling frequency and the second sampling frequency may also be different, and different sampling frequencies can be adjusted according to actual needs to adapt to different monitoring needs. For example, for a rapidly changing stress condition, a higher sampling frequency can be used to obtain more detailed data; while for a slowly changing condition, the sampling frequency can be reduced to reduce the amount of data.

[0056] In one embodiment of the present application, the second sampling frequency is greater than or equal to the first sampling frequency, and / or the ratio of the first sampling frequency to the second sampling frequency is between 0.8 and 1.2; and / or,

[0057] During the movement of the printing platform, the first sampling frequency is a fixed frequency or a dynamically changing frequency; and / or,

[0058] During the movement of the printing platform, the second sampling frequency is a fixed frequency or a dynamically changing frequency.

[0059] In this embodiment, the second sampling frequency may be greater than or equal to the first sampling frequency. As the printing platform moves, the sampling frequency increases. That is, at the beginning of the movement, a smaller sampling frequency is used to collect data to obtain the first detection value. During the continuous movement, a larger sampling frequency is used to collect data to obtain the second detection value. As the printing platform moves, the detection value can be obtained more and more quickly, thereby realizing timely detection of foreign matter.

[0060] Alternatively, the ratio of the first sampling frequency to the second sampling frequency is between 0.8 and 1.2, that is, the first sampling frequency may be greater than, less than, or equal to the second sampling frequency, but the difference between the two is not large, thereby ensuring the temporal synchronization of the two detection values.

[0061] In addition, in some embodiments, during the movement of the printing platform, the first sampling frequency may be a fixed frequency or a dynamically changing frequency, and / or the second sampling frequency may be a fixed frequency or a dynamically changing frequency. A fixed or dynamically changing frequency may be set according to actual acquisition needs. A fixed acquisition frequency may ensure that the interval of each data acquisition is the same, thereby providing a stable data stream; a dynamically changing acquisition frequency may be adjusted according to the actual situation during the printing process. For example, in the later stage of the movement of the printing platform, a higher acquisition frequency may be required to obtain more detailed data, while in the early stage of the movement of the printing platform, the acquisition frequency may be reduced to save resources.

[0062] Step 104: determining whether there is foreign matter in the 3D printing device according to the first detection value and / or the second detection value.

[0063] In this step, it is determined whether there is a foreign object in the 3D printing device based on the first detection value and the second detection value obtained. In one embodiment, the presence of a foreign object in the 3D printing device is determined based on the first detection value; in another embodiment, the presence of a foreign object in the 3D printing device is determined based on the second detection value; in yet another embodiment, the presence of a foreign object in the 3D printing device is determined based on the first detection value and the second detection value.

[0064] In one embodiment of the present application, the method further includes: when it is determined that there is a foreign object in the 3D printing device, executing a preset operation, the preset operation including at least one of issuing a foreign object alarm message, controlling the printing platform to stop moving, and controlling the printing platform to lift.

[0065] In this embodiment, when it is determined that there is a foreign object in the 3D printing device, a preset operation is performed. For example, when it is determined that there is a foreign object in the 3D printing device, a foreign object alarm message is issued to ensure that the user is informed of the existence of the foreign object in a timely manner, so that the user can take appropriate solutions in a timely manner. Alternatively, when it is determined that there is a foreign object in the 3D printing device, the printing platform is controlled to stop moving to prevent the printing platform from continuing to press down and causing damage to the device. Alternatively, when it is determined that there is a foreign object in the 3D printing device, the printing platform is controlled to rise to free up space for the user to take appropriate solutions.

[0066] In the embodiment of the present application, in the process of controlling the printing platform to execute the preset moving action, the force on the printing platform is detected in real time, and the foreign matter is first judged based on the first detection value corresponding to when the printing platform starts to move, so as to quickly determine whether the printing platform has contacted the foreign matter at the moment of starting to move, and timely detection of the foreign matter is achieved. Furthermore, if the printing platform does not contact the foreign matter at the moment of starting to move, the detection is continued based on the acquired detection value, which can ensure that the foreign matter detection is achieved during the entire preset moving action, avoid the problems such as the exposure screen being crushed due to the presence of foreign matter in the moving route of the printing platform, and increase the service life of the 3D printing equipment.

[0067] In one embodiment of the present application, the method further includes: determining a first threshold value based on preset information; wherein the preset information includes at least one of the following: platform parameters of the printing platform, viscosity of the resin in the material box of the 3D printing device, model of the 3D printing device, mode selected by the user, and user-defined parameters, the platform parameters of the printing platform include the weight and / or area of ​​the printing platform, the weight and / or area of ​​the printing platform is positively correlated with the first threshold value, and the viscosity of the resin is positively correlated with the first threshold value.

[0068] In this embodiment, when the printing platform starts to move, the printing platform may not contact the resin in the material tank, or it may contact the resin in the material tank (that is, the printing platform is below the resin liquid level). In order to avoid the force of the resin on the printing platform affecting the force on the printing platform and thus causing inaccurate foreign body detection, it is necessary to set the absolute value of the first threshold value to be greater than the force of the resin on the printing platform. In other words, only when the absolute value of the first threshold value is greater than the force of the resin on the printing platform, can it be ensured that when the absolute value of the first detection value is greater than the absolute value of the first threshold value, it is determined that the force of the foreign body on the printing platform is not the force of the resin on the printing platform.

[0069] The weight of the printing platform, the area of ​​the printing platform, and the viscosity of the resin determine the force exerted by the resin on the printing platform. Therefore, the first threshold value can be determined based on one or more of the weight of the printing platform, the area of ​​the printing platform, and the viscosity of the resin. Furthermore, since the model of the 3D printing device, the mode selected by the user, and the user-defined parameters can determine the weight of the printing platform, the area of ​​the printing platform, and the viscosity of the resin, the first threshold value can also be determined based on the model of the 3D printing device, the mode selected by the user, and the user-defined parameters.

[0070] By setting the first threshold, the influence of the force of the resin on the printing platform on the foreign matter detection is avoided, thereby improving the accuracy of the foreign matter detection.

[0071] In one embodiment of the present application, determining whether a foreign object exists in the 3D printing device according to the first detection value includes: when the first detection value is greater than a first threshold, determining that a foreign object exists in the 3D printing device.

[0072] In this embodiment, if the first detection value is greater than the first threshold value, it indicates that when the printing platform starts to move, the force applied to the printing platform is relatively large, that is, the printing platform has come into contact with a foreign object.

[0073] It is worth noting that in the embodiment of the present application, when it is detected that the first detection value is greater than the first threshold value, it is determined that a foreign object exists, and feedback is given immediately, without pausing the printing platform for a period of time to confirm whether the detection value becomes larger to determine the presence of a foreign object, thereby avoiding misunderstanding to the user due to the sudden suspension of the printing platform during the descent process.

[0074] In one embodiment, when it is detected that the first detection value is greater than the first threshold, the printing platform can continue to be controlled to make a preset movement action, and a second detection value can be detected. Only when it is determined that there is a foreign object in the 3D printing device according to the second detection value, it is determined that there is indeed a foreign object in the 3D printing device.

[0075] In one embodiment of the present application, determining whether a foreign object exists in the 3D printing device according to the second detection value includes:

[0076] When the second detection value is greater than the second threshold, it is determined that there is a foreign object in the 3D printing device, and the absolute value of the second threshold is greater than the absolute value of the first threshold;

[0077] When the second detection value is less than or equal to the second threshold, if it is determined based on the second detection value or based on the second detection value and the first detection value that the force change rate of the printing platform increases, it is determined that there is foreign matter in the 3D printing device.

[0078] In this embodiment, after determining that there is no foreign object based on the first detection value at the beginning of the movement, it is further determined whether there is a foreign object in the 3D printing device based on the second detection value obtained during the subsequent movement.

[0079] First, the second detection value is compared with the second threshold value, wherein the absolute value of the second threshold value is greater than the absolute value of the first threshold value. In one embodiment, the absolute value of the second detection value is compared with the absolute value of the second threshold value. When the detection value and the threshold value are positive numbers, when the second detection value is less than or equal to the second threshold value, it indicates that the force on the printing platform is small; when the second detection value is greater than the second threshold value, it indicates that the force on the printing platform is large. When the detection value and the threshold value are negative numbers, when the second detection value is greater than or equal to the second threshold value, that is, when the absolute value of the second detection value is less than or equal to the absolute value of the second threshold value, it indicates that the force on the printing platform is small; when the second detection value is less than the second threshold value, that is, when the absolute value of the second detection value is greater than the absolute value of the second threshold value, it indicates that the force on the printing platform is large.

[0080] It should be noted that if the printing platform is lowered to contact the resin in the material box, the force exerted by the resin on the printing platform will also cause a certain change in the detection value, but because the force exerted by the resin on the printing platform is small, this change is a small change. Therefore, if the second detection value is greater than the second threshold, it indicates that the printing platform is subjected to a large force, and it is not the force exerted by the resin on the printing platform (the force exerted by the resin on the printing platform is small), thereby determining the presence of foreign matter.

[0081] If the second detection value is less than or equal to the second threshold value, that is, the force applied to the printing platform is not large enough, in order to eliminate the problem of misjudgment caused by contact with the resin, the force change rate of the printing platform is continued to be judged based on the second detection value, or the force change rate of the printing platform is judged based on the second detection value and the first detection value. If it is determined that the force change rate of the printing platform has increased, it is determined that the interference of the resin has been eliminated, and it is confirmed that there is a foreign object in the 3D printing device.

[0082] The embodiment of the present application can monitor the magnitude and rate of change of the force applied to the printing platform in real time during the subsequent movement process, detect foreign objects, and improve the accuracy of foreign object detection.

[0083] In one embodiment of the present application, determining whether the force change rate of the printing platform increases includes:

[0084] calculating an absolute value of a difference between the second detection value and a target value, recorded as a first difference, calculating an absolute value of a difference between an acquisition time of the second detection value and an acquisition time of the first detection value, recorded as a second difference, the target value includes the first detection value or the first threshold value, and when a ratio of the first difference to the second difference is greater than or equal to a first preset value, determining that a force change rate of the printing platform increases; or,

[0085] The acquired second detection value includes a first sub-detection value and a second sub-detection value, the first sub-detection value and the second sub-detection value are acquired at adjacent times or at intervals, a first acquisition time of the first sub-detection value precedes a second acquisition time of the second sub-detection value, and when the second sub-detection value is greater than or equal to the first sub-detection value, or an absolute value or a ratio of a difference between the second sub-detection value and the first sub-detection value is greater than or equal to a second preset value, it is determined that the force change rate of the printing platform increases; or,

[0086] The absolute value of the difference between the second sub-detection value and the first sub-detection value is calculated, recorded as a third difference, and the absolute value of the difference between the second acquisition time and the first acquisition time is calculated, recorded as a fourth difference. When the ratio of the third difference to the fourth difference is greater than or equal to a third preset value, it is determined that the force change rate of the printing platform increases; or,

[0087] When the absolute values ​​of the plurality of second detection values ​​obtained increase in sequence, it is determined that the force change rate of the printing platform increases; or,

[0088] When the absolute values ​​of the obtained multiple second detection values ​​are all greater than or equal to the corresponding preset thresholds, it is determined that the force change rate of the printing platform increases, and the absolute values ​​of the preset thresholds corresponding to the multiple second detection values ​​increase in sequence; or,

[0089] A curve graph of the second detection value and time is constructed according to the acquired multiple second detection values ​​and the corresponding acquisition time. If the slope of the curve is greater than or equal to the fourth preset value, it is determined that the force change rate of the printing platform increases.

[0090] In this embodiment, judging whether the force change rate of the printing platform increases includes the following methods:

[0091] (1) The second detection value is a value, and the second detection value is subtracted from the target value to obtain a first difference value, the target value can be the first detection value or the first threshold value, and the acquisition time of the second detection value is subtracted from the acquisition time of the first detection value to obtain the second difference value. If the ratio of the first difference value to the second difference value is greater than or equal to the first preset value, it indicates that the second detection value has changed significantly compared with the target value within a certain period of time, which also indicates that the force change rate of the printing platform has increased.

[0092] (2) Two detection values ​​are obtained, including a first sub-detection value and a second sub-detection value. The first sub-detection value and the second sub-detection value are obtained at adjacent times or at intervals. The acquisition time of the first sub-detection value is the first acquisition time, and the acquisition time of the second sub-detection value is the second acquisition time. The first acquisition time is prior to the second acquisition time, that is, the second sub-detection value is obtained after the first sub-detection value, and the adjacent time is a unit time (for example, 0.5s, 1s, etc.), and the interval time is an integer multiple of the unit time.

[0093] Compare the second sub-detection value with the first sub-detection value. If the second sub-detection value is greater than or equal to the first sub-detection value, or the absolute value of the difference between the second sub-detection value and the first sub-detection value is greater than or equal to the preset value, or the ratio of the second sub-detection value to the first sub-detection value is greater than or equal to the preset value, it indicates that the detection value in the subsequent movement process gradually increases, which also indicates that the force change rate of the printing platform increases.

[0094] (3) Two detection values ​​are obtained, including a first sub-detection value and a second sub-detection value. The first sub-detection value and the second sub-detection value are obtained at adjacent times or at intervals. The adjacent time can be a unit time or an arbitrary time. The acquisition time of the first sub-detection value is the first acquisition time, and the acquisition time of the second sub-detection value is the second acquisition time. The first acquisition time is prior to the second acquisition time, that is, the second sub-detection value is obtained after the first sub-detection value.

[0095] The absolute value of the difference between the second sub-detection value and the first sub-detection value is calculated, recorded as the third difference, and the absolute value of the difference between the second acquisition time and the first acquisition time is calculated, recorded as the fourth difference. Then, the ratio of the third difference to the fourth difference is calculated, that is, the rate of change of the detection value over a period of time. When the ratio is greater than or equal to the third preset value, it indicates that the rate of change of the force on the printing platform increases.

[0096] (4) A plurality of second detection values ​​are obtained, and when the absolute values ​​of the plurality of second detection values ​​obtained increase successively, it is determined that the force change rate of the printing platform increases. The second detection value can be a negative number, so when the plurality of second detection values ​​increase successively, it is determined that the force change rate of the printing platform increases; the second detection value can be a negative number, so when the plurality of second detection values ​​decrease successively, it is equivalent to determining that the force change rate of the printing platform increases when the absolute values ​​increase successively.

[0097] (5) After obtaining multiple second detection values, each second detection value is compared with its corresponding preset threshold value, and the absolute values ​​of the preset threshold values ​​corresponding to the multiple second detection values ​​are increased in sequence. If the absolute values ​​of the multiple second detection values ​​are all greater than or equal to the corresponding preset threshold values, it indicates that the multiple second detection values ​​are gradually increasing, which also indicates that the force change rate of the printing platform is increasing.

[0098] (6) A plurality of second detection values ​​are obtained, and the acquisition time of each second detection value is recorded. A curve graph of the second detection value and time is constructed according to the plurality of second detection values ​​and the corresponding acquisition time. If the slope of the curve is greater than or equal to a fourth preset value, it indicates that the plurality of second detection values ​​are gradually increasing, which also indicates that the force change rate of the printing platform is increasing.

[0099] In the embodiment of the present application, it is possible to determine whether the force change rate of the printing platform increases in a variety of ways, thereby improving the flexibility of judging the force change rate of the printing platform.

[0100] In one embodiment of the present application, the acquired multiple second detection values ​​are multiple continuous second detection values.

[0101] In this embodiment, the multiple second detection values ​​obtained are multiple continuous detection values. The multiple continuous detection values ​​satisfy the above-mentioned judgment condition of the increase in the change rate of the printing platform, which can reflect the increase in the change rate of the printing platform. If the multiple continuous detection values ​​do not satisfy the judgment condition, the continuous count is reset and the judgment is made again.

[0102] For example, in one embodiment of the present application, the initial value of the first threshold M1 is set to -4kg, the second threshold M2 is set to -8kg, and the acquired detection values ​​are all negative. Figure 2 As shown, the printing platform is controlled to start descending along the Z axis, and the detection value representing the force condition of the printing platform is obtained during the entire descent process; the median value of the 10 detection values ​​obtained is calculated to obtain the first detection value P1, and it is determined whether P1 is less than M1. If P1 is less than M1 (equivalent to the absolute value of P1 being greater than the absolute value of M1), a foreign body alarm is triggered, and the printing platform is controlled to stop descending; if P1 is not less than M1 (equivalent to the absolute value of P1 being less than or equal to the absolute value of M1), the number of consecutive times that P1 is less than M1 is recorded as N=0.

[0103] Calculate the median value of the 10 test values ​​to obtain the second test value P2, and determine whether P2 is less than M2. If so, a foreign object alarm is triggered, and the printing platform is controlled to stop descending; if not, determine whether P2 is less than M1. If P2 is not less than M1, return to the step of recording the number of consecutive times N=0 that P1 is less than or equal to M1; if P2 is less than M1, then N++, and update M1=P2-0.5kg. Determine whether N is greater than or equal to 3. If so, it indicates that the values ​​of the test values ​​obtained for 3 consecutive times are gradually decreasing (the absolute value is gradually increasing); if not, continue to obtain the median value of the 10 test values.

[0104] In an embodiment of the present application, after the printing platform begins to descend along the Z axis, the force on the printing platform is monitored in real time, and it is determined whether there is a foreign object in the 3D printing device based on the force. Specifically, when the printing platform begins to move, the first detection value that represents the force on the printing platform at this time is monitored in real time, and then the first detection value is compared with the first threshold value, so as to quickly determine whether the printing platform has contacted a foreign object at the moment of starting to move, thereby achieving timely detection of foreign objects. If the printing platform does not contact a foreign object at the moment of starting to move, the second detection value that represents the force on the printing platform is continuously monitored, and it is determined whether the printing platform has contacted a foreign object based on the second detection value. When it is determined that the three consecutive second detection values ​​of the subsequent detection are gradually increasing, it is determined that the rate of change of the force on the printing platform is increasing, and it is determined that a foreign object is detected. In this way, timely and accurate detection of foreign objects in the 3D printing device is achieved.

[0105] In one embodiment of the present application, the method further includes:

[0106] When the printing platform has completed the preset moving action, controlling the printing platform to stop moving, and stopping for a third preset time period;

[0107] When the duration of the printing platform being stopped is greater than or equal to a third preset duration, obtaining a third detection value for characterizing a force condition of the printing platform;

[0108] When the third detection value is greater than the first threshold, it is determined that there is foreign matter in the 3D printing device.

[0109] In this embodiment, when the printing platform moves to the position, that is, when the preset moving action is completed, the printing platform is controlled to stop moving, and stops moving for a third preset time (for example, stop for 0.5s) to allow the resin to flow back, so as to reduce the influence of the resin backflow on the subsequent detection of the stress of the printing platform. Further, the stress of the printing platform is detected to obtain a third detection value, and the third detection value is compared with the first threshold value. When the third detection value is greater than the first threshold value, it is determined that there is a foreign body. In one embodiment, the absolute value of the third detection value is compared with the absolute value of the first threshold value. When the detection value and the threshold value are positive numbers, when the third detection value is less than or equal to the first threshold value, it indicates that the stress of the printing platform is small; when the third detection value is greater than the first threshold value, it indicates that the stress of the printing platform is large. When the detection value and the threshold value are negative numbers, when the third detection value is greater than or equal to the first threshold value, that is, when the absolute value of the third detection value is less than or equal to the absolute value of the first threshold value, it indicates that the stress of the printing platform is small; when the third detection value is less than the first threshold value, that is, when the absolute value of the third detection value is greater than the absolute value of the first threshold value, it indicates that the stress of the printing platform is large.

[0110] In the embodiment of the present application, after the printing platform is moved into place and it is determined that the resin backflow does not affect the force detection of the printing platform, foreign matter detection is performed based on the force applied to the printing platform, thereby realizing foreign matter detection when the printing platform is moved into place.

[0111] In one embodiment, when the printing platform performs a preset movement toward the material trough, when the printing platform moves into place, the distance between the printing platform and the bottom of the material box is the smallest. The foreign object detection performed at this time can detect small volumes, prevent damage to the equipment, and increase the service life of the equipment.

[0112] The present application also provides a 3D printing device, which includes:

[0113] A trough for containing resin;

[0114] A printing platform, used for carrying a printing model, wherein the printing platform moves relative to the material trough;

[0115] A memory storing programs or instructions;

[0116] A processor, when executing the program or instruction, implements each step of the control method embodiment of the above-mentioned 3D printing device, and can achieve the same technical effect. To avoid repetition, it is not repeated here.

[0117] The memory can be used to store software programs and various data. The memory may mainly include a first storage area for storing programs or instructions and a second storage area for storing data, wherein the first storage area may store an operating system, an application program or instructions required for at least one function (such as a sound playback function, an image playback function, etc.), etc. In addition, the memory may include a volatile memory or a non-volatile memory, or the memory may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), a static random access memory (SRAM), a dynamic random access memory (DRAM), a synchronous dynamic random access memory (SDRAM), a double data rate synchronous dynamic random access memory (DDRSDRAM), an enhanced synchronous dynamic random access memory (ESDRAM), a synchronous link dynamic random access memory (SLDRAM) and a direct memory bus random access memory (DRRAM). The memory in the embodiments of the present application includes but is not limited to these and any other suitable types of memory.

[0118] The processor may include one or more processing units; optionally, the processor integrates an application processor and a modem processor, wherein the application processor mainly processes operations related to the operating system, user interface, and application programs, and the modem processor mainly processes wireless communication signals, such as a baseband processor. It is understandable that the modem processor may not be integrated into the processor.

[0119] The embodiment of the present application further provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the control method embodiment of the above-mentioned 3D printing device is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0120] The present application also provides the following embodiments:

[0121] Embodiment 1, a control method of a 3D printing device, the method comprising:

[0122] Controlling the printing platform of the 3D printing device to perform a preset movement action in response to a preset instruction;

[0123] Acquire a first detection value used to characterize a force condition of the printing platform during movement of the printing platform;

[0124] When the first detection value is less than or equal to a first threshold, continuously controlling the printing platform to perform the preset movement action, and obtaining a second detection value for characterizing the force condition of the printing platform during the continuous movement of the printing platform;

[0125] The presence of foreign matter in the 3D printing device is determined according to the first detection value and / or the second detection value.

[0126] Embodiment 2, based on embodiment 1, controlling the printing platform to perform a preset movement action in response to a preset instruction includes:

[0127] In response to a preset instruction, the printing platform is controlled to move toward or away from the material slot of the 3D printing device to perform the preset movement.

[0128] Embodiment 3, based on embodiment 1, controlling the printing platform to perform a preset movement action in response to a preset instruction includes:

[0129] In response to a preset instruction for adjusting the Z-axis height of the printing platform, the printing platform is controlled to perform a preset movement action.

[0130] Embodiment 4, based on embodiment 1, the preset movement action is to control the printing platform to move a preset distance, move for a first preset time, or move to a preset position.

[0131] Embodiment 5, based on embodiment 1, the step of obtaining a first detection value for characterizing a force condition of the printing platform during movement of the printing platform includes:

[0132] When the printing platform starts to move, or when the printing platform starts to move for a second preset time, a first detection value for characterizing a force condition of the printing platform is acquired.

[0133] Embodiment 6, based on embodiment 1, the step of obtaining a first detection value for characterizing a force condition of the printing platform during movement of the printing platform includes:

[0134] Acquiring a first detection value for characterizing a force condition of the printing platform at a first sampling frequency;

[0135] The obtaining of a second detection value for characterizing a force condition of the printing platform during the continuous movement of the printing platform includes:

[0136] A second detection value for characterizing the force condition of the printing platform is obtained at a second sampling frequency, wherein the first sampling frequency is the same as or different from the second sampling frequency.

[0137] Embodiment 7, based on Embodiment 6, the second sampling frequency is greater than or equal to the first sampling frequency, and / or the ratio of the first sampling frequency to the second sampling frequency is between 0.8 and 1.2; and / or,

[0138] During the movement of the printing platform, the first sampling frequency is a fixed frequency or a dynamically changing frequency; and / or,

[0139] During the movement of the printing platform, the second sampling frequency is a fixed frequency or a dynamically changing frequency.

[0140] Embodiment 8, based on embodiment 1, comparing the first detection value with the first threshold value includes:

[0141] The absolute value of the first detection value is compared with the absolute value of the first threshold value.

[0142] Embodiment 9, based on embodiment 1, the continuously controlling the printing platform to perform the preset movement action includes:

[0143] Confirming whether the printing platform has completed the preset movement action, and continuing to move if the preset movement action has not been completed;

[0144] The method further comprises:

[0145] If the preset movement action has been completed, the movement is stopped.

[0146] Embodiment 10, based on embodiment 1, the method further comprises:

[0147] The first threshold is determined according to preset information; wherein the preset information includes at least one of the following: platform parameters of the printing platform, viscosity of the resin in the material box of the 3D printing device, model of the 3D printing device, a mode selected by a user, and user-defined parameters, the platform parameters of the printing platform include the weight and / or area of ​​the printing platform, the weight and / or area of ​​the printing platform is positively correlated with the first threshold, and the viscosity of the resin is positively correlated with the first threshold.

[0148] Embodiment 11, based on embodiment 1, determining the presence of foreign matter in the 3D printing device according to the first detection value includes:

[0149] When the first detection value is greater than the first threshold, it is determined that foreign matter exists in the 3D printing device.

[0150] Embodiment 12, based on embodiment 1, determining the presence of foreign matter in the 3D printing device according to the second detection value includes:

[0151] When the second detection value is greater than a second threshold, it is determined that there is a foreign object in the 3D printing device, and the absolute value of the second threshold is greater than the absolute value of the first threshold;

[0152] When the second detection value is less than or equal to a second threshold, if it is determined based on the second detection value or based on the second detection value and the first detection value that the force change rate of the printing platform increases, it is determined that foreign matter exists in the 3D printing device.

[0153] Embodiment 13, based on embodiment 12, determines whether the force change rate of the printing platform increases, including:

[0154] calculating an absolute value of a difference between the second detection value and a target value, recorded as a first difference, calculating an absolute value of a difference between an acquisition time of the second detection value and an acquisition time of the first detection value, recorded as a second difference, the target value includes the first detection value or the first threshold value, and when a ratio of the first difference to the second difference is greater than or equal to a first preset value, determining that a force change rate of the printing platform increases; or,

[0155] The acquired second detection value includes a first sub-detection value and a second sub-detection value, the first sub-detection value and the second sub-detection value are acquired at adjacent times or at intervals, a first acquisition time of the first sub-detection value precedes a second acquisition time of the second sub-detection value, and when the second sub-detection value is greater than or equal to the first sub-detection value, or an absolute value or a ratio of a difference between the second sub-detection value and the first sub-detection value is greater than or equal to a second preset value, it is determined that the force change rate of the printing platform increases; or,

[0156] The absolute value of the difference between the second sub-detection value and the first sub-detection value is calculated, recorded as a third difference, and the absolute value of the difference between the second acquisition time and the first acquisition time is calculated, recorded as a fourth difference. When the ratio of the third difference to the fourth difference is greater than or equal to a third preset value, it is determined that the force change rate of the printing platform increases; or,

[0157] When the absolute values ​​of the plurality of second detection values ​​obtained increase sequentially, it is determined that the force change rate of the printing platform increases; or,

[0158] When the absolute values ​​of the obtained plurality of second detection values ​​are all greater than or equal to the corresponding preset thresholds, it is determined that the force change rate of the printing platform increases, and the absolute values ​​of the preset thresholds corresponding to the plurality of second detection values ​​increase in sequence; or,

[0159] A curve graph of the second detection value and time is constructed according to the acquired multiple second detection values ​​and the corresponding acquisition time. If the slope of the curve is greater than or equal to a fourth preset value, it is determined that the force change rate of the printing platform increases.

[0160] Example 14, based on Example 13, the multiple second detection values ​​obtained are multiple continuous second detection values.

[0161] Example 15, based on Example 1, a method for obtaining the first detection value and / or the second detection value includes:

[0162] A plurality of detection values ​​for characterizing the stress condition of the printing platform are obtained, and a median value among the plurality of detection values ​​is used as the first detection value and / or the second detection value.

[0163] Embodiment 16, based on embodiment 1, the method further comprises:

[0164] When it is determined that there is a foreign object in the 3D printing device, a preset operation is performed, and the preset operation includes at least one of issuing a foreign object alarm message, controlling the printing platform to stop moving, and controlling the printing platform to lift.

[0165] Embodiment 17, based on embodiment 1, the method further comprises:

[0166] When the printing platform has completed the preset movement action, controlling the printing platform to stop moving, and stopping for a third preset time period;

[0167] When the duration of the printing platform being stopped is greater than or equal to a third preset duration, obtaining a third detection value for characterizing a force condition of the printing platform;

[0168] When the third detection value is greater than the first threshold, it is determined that there is foreign matter in the 3D printing device.

[0169] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0170] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A control method for a 3D printing device, It is characterized in that The method comprises: Controlling the printing platform of the 3D printing device to perform a preset movement action in response to a preset instruction; Acquire a first detection value used to characterize a force condition of the printing platform during movement of the printing platform; When the first detection value is less than or equal to a first threshold, continuously controlling the printing platform to perform the preset movement action, and obtaining a second detection value for characterizing the force condition of the printing platform during the continuous movement of the printing platform; The presence of foreign matter in the 3D printing device is determined according to the first detection value and / or the second detection value.

2. The method according to claim 1, It is characterized in that The controlling the printing platform to perform a preset movement action in response to a preset instruction includes: In response to a preset instruction, controlling the printing platform to move toward or away from the material slot of the 3D printing device to perform the preset movement; The controlling the printing platform to perform a preset movement action in response to a preset instruction includes: In response to a preset instruction for adjusting the Z-axis height of the printing platform, controlling the printing platform to perform a preset movement action; The preset movement action is to control the printing platform to move a preset distance, move for a first preset time, or move to a preset position.

3. The method according to claim 1, It is characterized in that The obtaining of a first detection value for characterizing a force condition of the printing platform during movement of the printing platform includes: When the printing platform starts to move, or when the printing platform starts to move for a second preset time, obtaining a first detection value for characterizing a force condition of the printing platform; The obtaining of a first detection value for characterizing a force condition of the printing platform during movement of the printing platform includes: Acquiring a first detection value for characterizing a force condition of the printing platform at a first sampling frequency; The obtaining of a second detection value for characterizing a force condition of the printing platform during the continuous movement of the printing platform includes: Acquiring a second detection value for characterizing a force condition of the printing platform at a second sampling frequency, wherein the first sampling frequency is the same as or different from the second sampling frequency; The second sampling frequency is greater than or equal to the first sampling frequency, and / or a ratio of the first sampling frequency to the second sampling frequency is between 0.8 and 1.2; and / or, During the movement of the printing platform, the first sampling frequency is a fixed frequency or a dynamically changing frequency; and / or, During the movement of the printing platform, the second sampling frequency is a fixed frequency or a dynamically changing frequency.

4. The method according to claim 1, It is characterized in that Comparing the first detection value with the first threshold value includes: comparing the absolute value of the first detection value with the absolute value of the first threshold; The continuously controlling the printing platform to perform the preset movement action includes: Confirming whether the printing platform has completed the preset movement action, and continuing to move if the preset movement action has not been completed; The method further comprises: If the preset movement action has been completed, the movement is stopped.

5. The method according to claim 1, It is characterized in that The method further comprises: The first threshold is determined according to preset information; wherein the preset information includes at least one of the following: platform parameters of the printing platform, viscosity of the resin in the material box of the 3D printing device, model of the 3D printing device, a mode selected by a user, and user-defined parameters, the platform parameters of the printing platform include the weight and / or area of ​​the printing platform, the weight and / or area of ​​the printing platform is positively correlated with the first threshold, and the viscosity of the resin is positively correlated with the first threshold.

6. The method according to claim 1, It is characterized in that The determining, according to the first detection value, that there is a foreign object in the 3D printing device includes: When the first detection value is greater than the first threshold, it is determined that a foreign object exists in the 3D printing device; The determining, according to the second detection value, that there is a foreign object in the 3D printing device includes: When the second detection value is greater than a second threshold, it is determined that there is a foreign object in the 3D printing device, and the absolute value of the second threshold is greater than the absolute value of the first threshold; When the second detection value is less than or equal to a second threshold, if it is determined that the force change rate of the printing platform increases based on the second detection value or based on the second detection value and the first detection value, it is determined that a foreign object exists in the 3D printing device; Determining whether the force change rate of the printing platform increases includes: calculating an absolute value of a difference between the second detection value and a target value, recorded as a first difference, calculating an absolute value of a difference between an acquisition time of the second detection value and an acquisition time of the first detection value, recorded as a second difference, the target value includes the first detection value or the first threshold value, and when a ratio of the first difference to the second difference is greater than or equal to a first preset value, determining that a force change rate of the printing platform increases; or, The acquired second detection value includes a first sub-detection value and a second sub-detection value, the first sub-detection value and the second sub-detection value are acquired at adjacent times or at intervals, a first acquisition time of the first sub-detection value precedes a second acquisition time of the second sub-detection value, and when the second sub-detection value is greater than or equal to the first sub-detection value, or an absolute value or a ratio of a difference between the second sub-detection value and the first sub-detection value is greater than or equal to a second preset value, it is determined that the force change rate of the printing platform increases; or, The absolute value of the difference between the second sub-detection value and the first sub-detection value is calculated, recorded as a third difference, and the absolute value of the difference between the second acquisition time and the first acquisition time is calculated, recorded as a fourth difference, and when the ratio of the third difference to the fourth difference is greater than or equal to a third preset value, it is determined that the force change rate of the printing platform increases; or, When the absolute values ​​of the plurality of second detection values ​​obtained increase sequentially, it is determined that the force change rate of the printing platform increases; or, When the absolute values ​​of the obtained plurality of second detection values ​​are all greater than or equal to the corresponding preset thresholds, it is determined that the force change rate of the printing platform increases, and the absolute values ​​of the preset thresholds corresponding to the plurality of second detection values ​​increase in sequence; or, constructing a curve graph of the second detection value and time according to the acquired plurality of the second detection values ​​and the corresponding acquisition time, and if the slope of the curve is greater than or equal to a fourth preset value, determining that the force change rate of the printing platform increases; The acquired multiple second detection values ​​are multiple continuous second detection values.

7. The method according to claim 1, It is characterized in that The method of obtaining the first detection value and / or the second detection value includes: A plurality of detection values ​​for characterizing the stress condition of the printing platform are obtained, and a median value among the plurality of detection values ​​is used as the first detection value and / or the second detection value.

8. The method according to claim 1, It is characterized in that The method further comprises: When it is determined that there is a foreign object in the 3D printing device, a preset operation is performed, wherein the preset operation includes at least one of issuing a foreign object alarm message, controlling the printing platform to stop moving, and controlling the printing platform to lift; The method further comprises: When the printing platform has completed the preset movement action, controlling the printing platform to stop moving, and stopping for a third preset time period; When the duration of the printing platform being stopped is greater than or equal to a third preset duration, obtaining a third detection value for characterizing a force condition of the printing platform; When the third detection value is greater than the first threshold, it is determined that there is foreign matter in the 3D printing device.

9. A 3D printing device, It is characterized in that include: A trough for containing resin; A printing platform, used for carrying a printing model, wherein the printing platform moves relative to the material trough; A memory storing programs or instructions; A processor, wherein when executing the program or instruction, the processor implements the steps of the control method of the 3D printing device according to any one of claims 1 to 8.

10. A readable storage medium having a program or instruction stored thereon, It is characterized in that When the program or instruction is executed by a processor, the steps of the control method of the 3D printing device according to any one of claims 1 to 8 are implemented.

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