Monitoring method of 3D printing equipment and 3D printing equipment

Abstract

The embodiment of the invention provides a monitoring method of 3D printing equipment and the 3D printing equipment. The monitoring method comprises the steps that the receiving signal intensity when a detection light beam emitted to a spray head is received is obtained; and based on the received signal strength, determining a monitoring result matched with the received signal strength and used for carrying out accumulated material monitoring on the spray head. By means of the mode, the problem that existing 3D printing equipment cannot effectively monitor accumulated materials of the spray head can be solved.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing equipment, and in particular to a monitoring method for 3D printing equipment and a 3D printing equipment. Background Art

[0002] 3D printing equipment, also known as three-dimensional printers, is based on digital model files and uses special wax materials, powdered metals or plastics to construct objects by printing layer by layer.

[0003] Among them, the nozzle is a component that is often used to output the material to be printed. However, when the nozzle outputs the material to be printed, it is easy to have the problem of material accumulation (filament adhesion or accumulation). However, most 3D printing equipment on the market usually cannot effectively monitor the material accumulation of the nozzle. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a monitoring method for 3D printing equipment and a 3D printing equipment, which can improve the problem that the existing 3D printing equipment cannot effectively monitor the material accumulation of the nozzle.

[0005] The first aspect of the present application provides a monitoring method for a 3D printing device, which includes obtaining a received signal strength when a detection light beam emitted to a nozzle is received; and determining a monitoring result matching the received signal strength for material accumulation monitoring of the nozzle based on the received signal strength.

[0006] Different from the related art, by emitting a detection beam to the nozzle and obtaining the received signal strength when the detection beam is received, the degree to which the detection beam is blocked can be determined, and then the degree of material accumulation on the nozzle can be determined.

[0007] Optionally, determining a monitoring result that matches the received signal strength for monitoring material accumulation on the nozzle based on the received signal strength includes: comparing the received signal strength with the reference signal strength to obtain a comparison result; and determining a monitoring result that matches the comparison result based on the comparison result.

[0008] Optionally, a monitoring result that matches the comparison result is determined based on the comparison result, including: if the comparison result is that the received signal strength is not less than the reference signal strength, then the monitoring result of the nozzle is determined to be a no-material accumulation state; if the comparison received signal strength is less than the reference signal strength, then the monitoring result of the nozzle is determined to be a material accumulation state.

[0009] Optionally, determining a monitoring result that matches the received signal strength for monitoring material accumulation on the nozzle based on the received signal strength includes: calculating a relative intensity parameter value between a reference signal strength and the received signal strength; the reference signal strength is the signal strength of the detection light beam received when no material accumulation occurs on the nozzle; determining a preset parameter value range in which the relative intensity parameter value is located in a plurality of different preset parameter value ranges, and determining a degree of material accumulation of the nozzle that matches the determined preset parameter value range; wherein the relative intensity parameter value includes an intensity difference between the reference signal strength and the received signal strength or an intensity ratio between the received signal strength and the reference signal strength.

[0010] Optionally, a monitoring result that matches the received signal strength is determined based on the received signal strength to monitor the material accumulation of the nozzle, including: determining a threshold intensity range in which the received signal strength is located in a plurality of different threshold intensity ranges, and determining a degree of material accumulation of the nozzle corresponding to the determined preset threshold intensity range; wherein the plurality of threshold intensity ranges are obtained by dividing between a preset minimum signal strength and a reference signal strength; and the reference signal strength is the signal strength of the detection light beam received when no material accumulation occurs on the nozzle.

[0011] Optionally, after determining a monitoring result of material accumulation monitoring on the nozzle that matches the received signal strength based on the received signal strength, the method further includes: executing a control strategy that matches the monitoring result.

[0012] Optionally, a control strategy matching the monitoring result is executed, including: if the monitoring result is determined to be the first level of material accumulation, controlling the printing device to stop model printing; if the monitoring result is determined to be the second level of material accumulation, controlling the cleaning device to clean the nozzle, and returning to execute to obtain the received signal strength when the detection light beam emitted to the nozzle is received; wherein the severity of the first level of material accumulation is greater than the severity of the second level of material accumulation.

[0013] Optionally, before obtaining the received signal strength when the detection light beam emitted to the nozzle is received, it includes: detecting whether the nozzle and / or the environment of the nozzle meets the preset light measurement conditions; if so, obtaining the received signal strength when the detection light beam emitted to the nozzle is received.

[0014] Optionally, detecting whether the nozzle and / or the environment of the nozzle meets the preset light measurement conditions includes: detecting the initial material accumulation degree of the nozzle; determining whether the initial material accumulation degree of the nozzle is within a preset material accumulation degree range; if so, determining that the nozzle meets the preset light measurement conditions; if not, determining that the nozzle does not meet the preset light measurement conditions, and then controlling the printing device to stop model printing.

[0015] Optionally, detecting the initial material accumulation degree of the nozzle includes: photographing the nozzle by a first camera device to obtain a nozzle image, and identifying the initial material accumulation degree of the nozzle in the nozzle image.

[0016] Optionally, determining whether the nozzle meets the preset light measurement conditions includes: obtaining a model image of the current model obtained by photographing the current model by the second camera device during the model printing process, and calculating the probability of successful printing of the current model based on the model image; judging whether the probability is less than a preset probability; if the probability is less than the preset probability, controlling the printing device to stop model printing, and / or controlling the printing device to remind the user.

[0017] Optionally, detecting whether the nozzle and / or the environment of the nozzle meets preset light measurement conditions includes: detecting whether there is an obstruction on the emission light path of the detection light beam; if not, determining that the environment of the nozzle meets the preset light measurement conditions.

[0018] Optionally, detecting whether there is an obstruction on the emission light path of the detection light beam includes: acquiring an environmental image obtained by photographing the environment of the nozzle by a second camera device, and identifying in the environmental image whether there is an obstruction on the emission light path.

[0019] Optionally, obtaining the received signal strength when the detection light beam emitted to the nozzle is received includes: emitting the detection light beam to the nozzle through an optical transmitter; and receiving the received signal strength of the detection light beam after passing through the nozzle through an optical receiver.

[0020] The second aspect of the present application provides a 3D printing device, which includes a device body, a photoelectric sensor, a memory and a processor; wherein the device body has a nozzle for controlling the outflow of heated consumables; the photoelectric sensor is arranged on the printing device body, and is used to emit and receive a detection light beam passing through the nozzle; the processor is coupled to the photoelectric sensor and the memory, the memory stores program instructions, and the processor reads the program instructions to implement a monitoring method for the printing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the principle of the photoelectric sensor monitoring the nozzle of the 3D printing device embodiment of the present application;

[0022] Figure 2 It is a flow chart of an embodiment of the monitoring method of the present application;

[0023] Figure 3 It is a sub-step of step S050 of the monitoring method embodiment of the present application;

[0024] Figure 4 It is a sub-step of step S050 of the monitoring method embodiment of the present application. DETAILED DESCRIPTION

[0025] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0026] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0027] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed", "set" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be directly connected or indirectly connected. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0028] The following 3D printing device embodiments of the present application describe an exemplary structure of a 3D printing device.

[0029] The 3D printing device (also referred to as a printing device) may include a device body. The device body may include a consumable output device and a carrying pallet. The consumable output device may be used to output consumables or materials to be printed. The carrying pallet may be used to carry a finished model or a semi-finished model printed by the consumable output device.

[0030] See also Figure 1 Optionally, the consumable material output device may include a nozzle 10 and a hot end 15. The hot end 15 may be used to heat the consumable material. The nozzle 10 may control the flow of the heated consumable material.

[0031] Optionally, the support plate may also have a heating function, for example, the support plate may have a heating element. In this case, the support plate may also be referred to as a hot bed. The hot bed may maintain the temperature of the semi-finished model being printed during the printing process, so that the semi-finished model and the consumables output by the nozzle 10 can be firmly bonded together. In addition, the hot bed may keep the semi-finished model or finished model being printed warm, thereby reducing the possibility of warping and deformation of the printed model (semi-finished model or finished model) due to thermal expansion and contraction.

[0032] Optionally, the 3D printing device may further include a frame. The frame is used to enclose a printing space so that the printed model can be formed inside the printing space. The nozzle 10 may be located inside the frame. The support plate may also be disposed inside the frame. The frame may be used to isolate the printing space from the external space to reduce the possibility of the semi-finished model or the finished model being contaminated by external factors during the printing process.

[0033] Optionally, the 3D printing device may further include a photoelectric sensor 20. The photoelectric sensor 20 is disposed on the main body of the 3D printing device, and is used to emit and / or receive a detection beam passing through the nozzle 10. The photoelectric sensor 20 may include a light receiver 22 and a light transmitter 21. The light transmitter 21 may emit a detection beam to the light receiver 22. The light receiver 22 may be used to receive the detection beam. The nozzle 10 may be placed between the light transmitter 21 and the light receiver 22, so that the detection beam emitted by the photoelectric sensor 20 to the light receiver 22 may pass through the nozzle 10. Generally, the shape of the nozzle 10 is fixed, so the light intensity of the detection beam obtained by the light receiver 22 is usually fixed. When the intensity of the detection beam obtained by the light receiver 22 decreases, it means that the portion of the detection beam that is blocked during the propagation process increases, and accordingly, it can be judged that the material accumulation at the nozzle 10 increases. Further, according to the intensity of the detection beam obtained by the light receiver 22, the severity of the material accumulation can also be calculated.

[0034] Optionally, the photoelectric sensor 20 may be a laser beam sensor, thereby being able to stably monitor the material accumulation of the nozzle 10 .

[0035] Optionally, the 3D printing device further includes a memory and a processor. The memory stores program instructions. The processor is coupled to the photoelectric sensor 20 to obtain data from the photoelectric sensor 20. In addition, the memory can be coupled to the memory for reading program instructions to implement the monitoring method of the 3D printing device.

[0036] The processing circuit may also be referred to as a CPU (Central Processing Unit). The processing circuit may be an integrated circuit chip having the ability to process signals. The processing circuit may also be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a graphics processing unit (GPU) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. The general-purpose processor may be a microprocessor (MCU) or the processor may also be any conventional processor, etc.

[0037] Optionally, the 3D printing device further includes a camera. The camera can be used to acquire image data. The processor can acquire the image data acquired by the camera to process the image data. Optionally, the camera can be used to acquire image data of the nozzle 10. In this case, the processor can determine the material accumulation of the nozzle 10 based on the image data of the nozzle 10. Optionally, the camera can be used to acquire image data of a printed model (a semi-finished model or a finished model). In this case, the processor can determine the print quality of the model based on the image data of the printed model.

[0038] The camera device may include a first camera device and a second camera device. The first camera device and the second camera device may be coupled to the processor. The first camera device may be disposed at the nozzle 10 to obtain image data of the nozzle 10. The second camera device may be disposed in the frame, facing the printing space, to obtain image data of the nozzle 10 and / or image data of the printed model. The field of view of the first camera device may be smaller than the field of view of the second camera device.

[0039] The inventor of the present application has found through research that in the related technology of identifying the material accumulation at the nozzle through machine vision, since the recognition algorithm may not be mature enough, it can usually only accurately identify when the material accumulation at the nozzle is very serious. When the material accumulation at the nozzle is very serious, the material accumulation will affect the printing of the model, thereby greatly reducing the success rate of the model printing. In order to solve the above problems, the present application proposes the following embodiments.

[0040] The following monitoring method embodiment of the 3D printing device of the present application (hereinafter referred to as the monitoring method embodiment) describes exemplary steps of the monitoring method of the 3D printing device. The monitoring method embodiment of the present application can be used in the above-mentioned 3D printing device embodiment.

[0041] See also Figure 2 The monitoring method may include: obtaining a received signal strength when a detection light beam emitted to the nozzle is received (step S100); and determining a monitoring result matching the received signal strength for material accumulation monitoring of the nozzle based on the received signal strength (step S200).

[0042] Different from the related art, by emitting a detection beam to the nozzle and obtaining the received signal strength when the detection beam is received, the degree to which the detection beam is blocked can be determined, and then the degree of material accumulation on the nozzle can be determined.

[0043] In some embodiments, step S100 includes: transmitting a detection light beam to the nozzle through a light transmitter; and receiving a received signal strength of the detection light beam after passing through the nozzle through a light receiver.

[0044] In some embodiments, step S200 may include: comparing the received signal strength with the reference signal strength to obtain a comparison result; and determining a monitoring result that matches the comparison result according to the comparison result.

[0045] Among them, determining the monitoring result that matches the comparison result based on the comparison result may include: if the comparison result is that the received signal strength is not less than the reference signal strength, then determining that the monitoring result of the nozzle is in a no-material accumulation state; if the compared received signal strength is less than the reference signal strength, then determining that the monitoring result of the nozzle is in a material accumulation state.

[0046] In some embodiments, step S200 may include: calculating a relative strength parameter value between a reference signal strength and a received signal strength; determining a preset parameter value range in which the relative strength parameter value is located in a plurality of different preset parameter value ranges, and determining a degree of material accumulation of the nozzle that matches the determined preset parameter value range.

[0047] The reference signal strength may be the signal strength of the detection light beam received when the nozzle does not accumulate material. In other embodiments, the reference signal strength may also be the signal strength of the detection light beam received when there is no nozzle. Optionally, the relative strength parameter value includes the strength difference between the reference signal strength and the received signal strength.

[0048] Take the relative strength parameter value as the intensity ratio of the received signal strength and the reference signal strength as an example; assuming that the multiple preset parameter ranges are 0-30%, 31%-80%, and 81%-100%, respectively, and the relative strength parameter value is 85%, it means that the nozzle is at a material accumulation level corresponding to 81%-100% (for example, slight material accumulation). Of course, the division of the above multiple preset parameter ranges is only exemplary, so users or engineers can also divide multiple preset parameter ranges based on experience. In addition, set multiple preset parameter ranges, and then determine which specific range the relative strength parameter value of the nozzle is in. In this case, different control strategies can be executed for the specific preset parameter range in which the relative parameter value of the nozzle is located.

[0049] In some other embodiments, step S200 may include: determining a threshold intensity range in which the received signal intensity is located among a plurality of different threshold intensity ranges, and determining a material accumulation degree corresponding to the determined preset threshold intensity range of the nozzle.

[0050] The multiple threshold intensity ranges are obtained by dividing between a preset minimum signal intensity and a reference signal intensity. Optionally, the reference signal intensity is the signal intensity of the detection light beam received when no material accumulation occurs on the nozzle.

[0051] Taking the reference signal strength of 70% as an example (which means that the nozzle can block 30% of the detection light beam), the multiple threshold intensity ranges are 0-30%, 31%-60%, and 61%-70%. If the signal receiving strength is 65%, it means that the nozzle is at a material accumulation level corresponding to 61%-70% (for example, slight material accumulation). Similarly, the division of the above multiple threshold intensity ranges is only exemplary, so users or engineers can also divide multiple threshold intensity ranges based on experience. In addition, multiple threshold intensity ranges are set, and then it is determined in which specific range the signal receiving strength of the nozzle is. In this case, different control strategies can be executed according to the specific threshold intensity range in which the signal receiving strength of the nozzle is located.

[0052] It should be noted that step S200 may include at least one of the above-mentioned multiple specific embodiments to generate corresponding monitoring results.

[0053] Considering that there is usually material accumulation on the nozzle, when the accumulation is relatively minor, such as the presence of consumable filaments on the nozzle, according to production experience, this situation generally does not affect the quality of the printed model. As the degree of material accumulation on the nozzle gradually increases, the possibility of material accumulation affecting the quality of the printed model becomes higher and higher. When the material accumulation on the nozzle is very serious, the probability of failure to print the model will be very high.

[0054] In some embodiments, after step S200, the method includes: executing a control strategy that matches the monitoring result (step S300).

[0055] Optionally, step S300 includes: if the monitoring result is determined to be the first level of material accumulation, controlling the 3D printing device to stop model printing; if the monitoring result is determined to be the second level of material accumulation, controlling the cleaning device to clean the nozzle, and returning to step S100. The severity of the first level of material accumulation is greater than the severity of the second level of material accumulation.

[0056] Optionally, the first level of material accumulation and the second level of material accumulation may correspond to at least two preset parameter ranges in a plurality of preset parameter ranges, or correspond to at least two threshold intensity ranges in a plurality of threshold intensity ranges. For example, the plurality of preset parameter ranges include 0-30%, 31%-80%, 81%-100%. If the received signal strength falls within the preset parameter range of 0-30%, it can be obtained that the monitoring result is that the nozzle is in the first level of material accumulation state; if the received signal strength falls within the preset parameter range of 31%-80%, it can be obtained that the monitoring result is that the nozzle is in the second level of material accumulation state.

[0057] Similarly, for multiple threshold intensity ranges including 0-30%, 31%-60%, and 61%-70%, if the received signal strength falls within the threshold intensity range of 0-30% at this time, it can be concluded that the monitoring result is that the nozzle is in the first level of material accumulation state; if the received signal strength falls within the threshold intensity range of 31-60% at this time, it can be concluded that the monitoring result is that the nozzle is in the second level of material accumulation state.

[0058] In addition, it should be noted that the percentage divisions of the above-mentioned multiple threshold intensity ranges and preset parameter ranges are merely exemplary and should not be construed as limitations on the present application.

[0059] In some embodiments, before step S100, the process includes: detecting whether the nozzle and / or the environment of the nozzle meets a preset light measurement condition (step S050); if so, executing step S100.

[0060] As mentioned above, even if the algorithm is not mature enough, machine vision can still effectively identify that the nozzle is in a state of severe material accumulation. Therefore, before step S100, it is also possible to preliminarily determine whether the nozzle is in a state of severe material accumulation through machine vision. Specifically, it is possible to obtain image data of the nozzle, and compare the image data of the nozzle obtained in real time with the image data of the pre-configured nozzle without material accumulation to determine whether there is foreign matter (material accumulation) on the nozzle. Of course, in other examples, it is also possible to train a neural network in advance with a large amount of image data of nozzles with material accumulation to obtain a neural network with foreign matter recognition function, and then use the neural network to identify the image data of the nozzle obtained in real time to determine whether there is foreign matter (material accumulation) on the nozzle.

[0061] See also Figure 3 Optionally, step S050 may include: detecting the initial material accumulation degree of the nozzle (step S060); determining whether the initial material accumulation degree of the nozzle is within a preset material accumulation degree range (step S061); if so, determining that the nozzle meets the preset light measurement condition (step S062). Correspondingly, if not, determining that the nozzle does not meet the preset light measurement condition, and then controlling the printing device to stop model printing (step S063). In other words, if the machine vision identifies that the nozzle has serious material accumulation, the printing can be stopped directly, so that the printing device can react sensitively.

[0062] Optionally, step S060 includes: photographing the nozzle by a first camera device to obtain a nozzle image, and identifying the initial material accumulation degree of the nozzle in the nozzle image. Of course, in other embodiments, step S060 may also include photographing the nozzle by a second camera device to obtain a nozzle image, and identifying the initial material accumulation degree of the nozzle in the nozzle image.

[0063] In some embodiments, after step S062, it also includes: obtaining a model image of the current model obtained by taking a picture of the current model by the second camera device during the model printing process, and calculating the probability of successful printing of the current model based on the model image; if the probability is less than a preset probability, controlling the printing device to stop model printing; and / or controlling the printing device to remind the user.

[0064] That is, the model image of the current model captured by the second camera device can be used to calculate the probability of successful printing of the current model. If the probability of successful printing is high (for example, more than 80%), printing can continue; if the probability of successful printing is low (for example, the degree of material accumulation is serious or the current model is damaged), model printing can be stopped or the user can be reminded to check in time.

[0065] Furthermore, if the material accumulation on the nozzle is not very serious, the model still has a probability of printing successfully. For example, when the nozzle has slight material accumulation, the probability of successful model printing is very high, and printing can continue at this time. If the degree of material accumulation on the nozzle increases during further printing, the probability of successful printing of the corresponding model decreases, and printing can be stopped or the user can be reminded to clean the nozzle. In addition, after stopping printing, the nozzle can also be controlled to move to the cleaning area of ​​the cleaning device, and then the cleaning device is controlled to clean the nozzle. After cleaning, the nozzle is controlled to reset and continue printing. In this case, the 3D printing equipment can automatically clean the nozzle, and can continue printing after cleaning, thereby improving printing efficiency. In other examples, after the nozzle moves to the cleaning area, it can also wait for the user to manually clean it.

[0066] Considering that the photoelectric sensor may not be able to identify whether there are obstructions other than the nozzle on the emission light path, if the obstruction and the nozzle block the detection beam together, the received signal strength of the detection beam cannot accurately reflect the degree of material accumulation. Therefore, in order to ensure the accuracy of the photoelectric sensor in identifying the degree of material accumulation, machine vision can be used to pre-determine whether there are obstructions on the emission light path that affect the operation of the photoelectric sensor.

[0067] See also Figure 4 Optionally, step S050 includes: detecting whether there is an obstruction in the emission path of the detection light beam (step S070); if not, determining that the environment of the nozzle meets the preset light measurement conditions (step S071); if so, determining that the environment of the nozzle does not meet the preset light measurement conditions (step S072).

[0068] Among them, step S070 may include: obtaining an environment image obtained by photographing the environment of the printhead by the second camera device, and identifying whether there is an obstruction on the emission light path in the environment image. That is, if there is an obstruction on the emission light path of the detection light beam, it can be determined that the environment of the printhead does not meet the preset light measurement condition; if there is no obstruction on the emission light path, it can be determined that the environment of the printhead meets the preset light measurement condition.

[0069] In addition, step S050 (detecting whether the nozzle and / or the environment of the nozzle meets the preset light measurement conditions) can be used to preliminarily identify the initial material accumulation level, and can also be used to determine whether there is an obstruction on the emission light path. Of course, step S050 can also be used only for preliminarily identifying the initial material accumulation level, or only for determining whether there is an obstruction on the emission light path.

[0070] In summary, the present application can determine the degree to which the detection beam is blocked, and further determine the degree of material accumulation on the nozzle, by emitting a detection beam to the nozzle and obtaining the received signal strength when the detection beam is received.

[0071] The above description is only an implementation mode of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A monitoring method for 3D printing equipment, characterized in that: include: Acquire the received signal strength when the detection light beam emitted to the nozzle is received; A monitoring result matching the received signal strength for monitoring material accumulation on the nozzle is determined based on the received signal strength.

2. The monitoring method according to claim 1, characterized in that: The method of determining a monitoring result matching the received signal strength for monitoring material accumulation on the nozzle based on the received signal strength includes: Comparing the received signal strength with a reference signal strength to obtain a comparison result; A monitoring result matching the comparison result is determined according to the comparison result.

3. The monitoring method according to claim 2, characterized in that: The determining, according to the comparison result, a monitoring result matching the comparison result comprises: If the comparison result is that the received signal strength is not less than the reference signal strength, then determining that the monitoring result of the nozzle is a state of no material accumulation; If the compared received signal strength is less than the reference signal strength, it is determined that the monitoring result of the nozzle is a material accumulation state.

4. The monitoring method according to claim 1, characterized in that: The method of determining a monitoring result matching the received signal strength for monitoring material accumulation on the nozzle based on the received signal strength includes: Calculating a relative strength parameter value between a reference signal strength and the received signal strength; the reference signal strength is the signal strength of the detection light beam received when no material accumulation occurs on the nozzle; Determine the preset parameter value range in which the relative intensity parameter value is located among a plurality of different preset parameter value ranges, and determine the material accumulation degree of the nozzle that matches the determined preset parameter value range; The relative strength parameter value includes a strength difference between the reference signal strength and the received signal strength or a strength ratio between the received signal strength and the reference signal strength.

5. The monitoring method according to claim 1, characterized in that: The method of determining a monitoring result matching the received signal strength for monitoring material accumulation on the nozzle based on the received signal strength includes: Determine the threshold intensity range in which the received signal intensity is located among a plurality of different threshold intensity ranges, and determine the material accumulation degree of the nozzle corresponding to the determined preset threshold intensity range; The multiple threshold intensity ranges are obtained by dividing between a preset minimum signal intensity and a reference signal intensity; the reference signal intensity is the signal intensity of the detection light beam received when no material accumulation occurs on the nozzle.

6. The monitoring method according to claim 1, characterized in that: After determining the monitoring result of material accumulation monitoring on the nozzle based on the received signal strength and matching the received signal strength, the method further comprises: A control strategy matching the monitoring result is executed.

7. The monitoring method according to claim 6, characterized in that: The executing a control strategy matching the monitoring result includes: If it is determined that the monitoring result is the first level of material accumulation, controlling the printing device to stop model printing; If it is determined that the monitoring result is the second level of material accumulation, the cleaning device is controlled to clean the nozzle, and the step of obtaining the received signal strength when the detection light beam emitted to the nozzle is received is returned to execute; wherein the severity of the first level of material accumulation is greater than the severity of the second level of material accumulation.

8. The monitoring method according to claim 1, characterized in that: Before obtaining the received signal strength when the detection light beam emitted to the nozzle is received, the method includes: Detecting whether the nozzle and / or the environment of the nozzle meets preset light measurement conditions; If the condition is satisfied, the step of obtaining the received signal strength when the detection light beam emitted to the nozzle is received is performed.

9. The monitoring method according to claim 8, characterized in that: The detecting whether the nozzle and / or the environment of the nozzle meets the preset light measurement conditions includes: Detecting the initial material accumulation level of the nozzle; Determining whether the initial material accumulation level of the nozzle is within a preset material accumulation level range; If yes, it is determined that the nozzle meets the preset light measurement condition; If not, it is determined that the nozzle does not meet the preset light measurement condition, and then the printing device is controlled to stop model printing.

10. The monitoring method according to claim 9, characterized in that: The detecting the initial material accumulation degree of the nozzle includes: photographing the nozzle by a first camera device to obtain a nozzle image, and identifying the initial material accumulation degree of the nozzle in the nozzle image.

11. The monitoring method according to claim 9, characterized in that: The determining that the nozzle meets the preset light measurement condition includes: Acquire a model image of the current model obtained by taking a picture of the current model by the second camera device during the model printing process, and calculate the probability of successful printing of the current model according to the model image; Determining whether the probability is less than a preset probability; If the probability is less than a preset probability, the printing device is controlled to stop printing the model, and / or the printing device is controlled to remind the user.

12. The monitoring method according to claim 8, characterized in that: The detecting whether the nozzle and / or the environment of the nozzle meets the preset light measurement conditions includes: Detecting whether there is an obstruction on the emission light path of the detection light beam; If not, it is determined that the environment of the nozzle meets the preset light measurement condition.

13. The monitoring method according to claim 12, characterized in that: The detecting whether there is an obstruction on the emission light path of the detection light beam comprises: An environment image obtained by photographing the environment of the nozzle by a second camera device is acquired, and whether there is an obstruction on the emission light path is identified in the environment image.

14. The monitoring method according to claim 1, characterized in that: The obtaining of the received signal strength when the detection light beam emitted to the nozzle is received comprises: emitting the detection light beam to the nozzle through a light emitter; The received signal strength of the detection light beam after passing through the nozzle is received by an optical receiver.

15. A 3D printing device, characterized in that: include: The main body of the device has a nozzle that controls the outflow of heated consumables; A photoelectric sensor, disposed on the printing device body, for emitting and receiving a detection light beam passing through the nozzle; A processor and a memory, wherein the processor is coupled to the photoelectric sensor and the memory, the memory stores program instructions, and the processor reads the program instructions to implement the monitoring method of the printing device according to any one of claims 1 to 14.

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