Print anomaly detection method and 3D printer

Abstract

The application discloses a printing abnormality detection method and a 3D printer, and relates to the technical field of printing. The printing abnormality detection method comprises the following steps: according to a pre-configured ultrasonic control strategy, an ultrasonic detection mechanism is caused to form an ultrasonic detection sound beam in a material tray; and whether there is a foreign matter in the material tray is judged according to the echo of the ultrasonic detection sound beam. By forming a transverse ultrasonic detection sound beam in the material tray, whether there is a foreign matter in the material tray can be detected according to the echo of the ultrasonic detection sound beam, and by judging whether there is a foreign matter in the material tray, the user can find the foreign matter in the material tray in time, so that the printing quality is not affected by the long-time existence of the foreign matter, and the printing is not failed, and a large amount of printing materials are not wasted. The 3D printer provided by the application can be used to realize the printing abnormality detection method.

Description

Technical Field

[0001] This application relates to the field of printing technology, and more specifically, to a method for detecting printing anomalies and a 3D printer. Background Technology

[0002] 3D printing is a rapid manufacturing technology that uses a computer-controlled layer-by-layer manufacturing process to build objects layer by layer based on the additive manufacturing principle, ultimately transforming digital models of materials such as metals, plastics, and resins from computer images into physical substances. 3D printing technology is widely used in various fields, including manufacturing, medicine, architectural design, and artistic creation. There are several types of 3D printing technologies, including Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS), Electron Beam Melting (EBM), Liquid Crystal Display (LCD), and Digital Light Processing (DLP). Stereolithography 3D printing is a 3D printing technology based on the principle of photopolymerization. It uses liquid photopolymer resin and a light source system to build objects layer by layer. When irradiated with ultraviolet (UV) light, the photosensitive resin undergoes a chemical reaction in the light-receiving areas, solidifying into a solid model. During the 3D printing process, the forming platform of the stereopolymer 3D printer is lowered into the liquid photopolymer resin, and the light source projects light according to a predetermined rule, causing the resin to solidify at designated locations on the forming platform. After each slice layer has cured, the molding platform gradually rises, and new liquid resin flows below the molding platform to replace the cured layer. This process is repeated until the entire model is printed.

[0003] During 3D printing, foreign objects may enter the material tray used to hold the liquid printing material. These foreign objects may be caused by the printed part or its local structure falling from the forming platform into the tray due to insufficient adhesion; or they may be external objects falling into the tray. If these foreign objects are not removed promptly, they can seriously affect the normal operation of 3D printing, leading to problems such as decreased print quality, reduced printing efficiency, and wasted printing material. Summary of the Invention

[0004] The purpose of this application includes, for example, providing a printing anomaly detection method and a 3D printer, which can detect the presence of foreign objects in the material tray in a timely and accurate manner, thereby improving printing quality and efficiency and reducing waste of printing materials.

[0005] The embodiments of this application can be implemented as follows:

[0006] In a first aspect, this application provides a printing anomaly detection method applied to a 3D printer. The 3D printer includes a material tray for containing printing material, an ultrasonic detection mechanism, and a forming platform for attaching printed parts. The printing anomaly detection method includes:

[0007] According to the pre-configured ultrasonic control strategy, the ultrasonic detection mechanism forms an ultrasonic detection beam within the material tray;

[0008] The presence of foreign objects in the material tray is determined by the echo of the ultrasonic detection beam.

[0009] In an optional implementation, the ultrasonic control strategy is configured as follows:

[0010] After the 3D printer prints the preset target number of layers, an ultrasonic testing command is executed to cause the ultrasonic testing mechanism to form an ultrasonic detection beam within the material tray; or

[0011] After the 3D printer is started, the ultrasonic testing mechanism continuously generates ultrasonic detection beams.

[0012] In an optional implementation, the ultrasonic testing mechanism includes multiple ultrasonic probes, and the ultrasonic control strategy is configured as follows:

[0013] Multiple ultrasonic probes are controlled to form ultrasonic detection beams sequentially or synchronously.

[0014] In an optional implementation, the ultrasonic control strategy is further configured as follows:

[0015] Control the ultrasonic probe beam to scan along a preset path within the material tray.

[0016] In an optional implementation, the ultrasonic control strategy is further configured as follows:

[0017] The frequency of the ultrasonic detection beam is determined based on at least one of the characteristics of the printing material, the structural features of the tray, and the required resolution and saturation.

[0018] In an optional implementation, the frequency range of the ultrasonic detection beam is 20 kHz to 200 MHz.

[0019] In an optional implementation, the step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes:

[0020] Obtain the echo delay time of the ultrasonic probe beam;

[0021] Determine whether the echo delay time is within the preset delay threshold range;

[0022] If so, then it is determined that there are no foreign objects in the tray;

[0023] Otherwise, it is determined that there are foreign objects in the material tray.

[0024] In an optional implementation, the step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes:

[0025] The echo delay time of the ultrasonic probe beam is obtained, and the echo delay time is compared with the preset standard delay time without residue or foreign matter to obtain the time deviation value.

[0026] Determine whether the time deviation value is within the preset time threshold range;

[0027] If so, then it is determined that there are no foreign objects in the tray;

[0028] Otherwise, it is determined that there are foreign objects in the material tray.

[0029] In an optional implementation, the preset delay threshold range is a threshold range with a reference value as the midpoint, where the reference value is the echo delay time of the ultrasonic detection beam when there are no foreign objects in the tray.

[0030] In an optional implementation, the step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes:

[0031] Obtain echo intensity information from the ultrasonic detection beam;

[0032] The presence of foreign objects in the tray is determined based on the echo intensity information.

[0033] In an optional implementation, determining whether there are foreign objects in the tray based on the echo intensity information includes:

[0034] When the echo intensity information is strong echo, it is determined that there is a solid foreign object;

[0035] When the echo intensity information is weak echo, it is determined that there is a semi-solidified foreign object;

[0036] When the echo intensity information is no echo, it is determined that there is no foreign object.

[0037] In an optional implementation, after acquiring the echo intensity information of the ultrasonic probe beam, the method further includes:

[0038] Convert echo intensity information into an echo image;

[0039] The presence of foreign objects in the material tray is determined based on the echo image, and the echo image is displayed; different echo intensity information corresponds to different grayscale values ​​in the echo image.

[0040] In an optional implementation, the printing anomaly detection method further includes:

[0041] A longitudinal ultrasonic detection beam is formed within the material tray;

[0042] When it is determined that there are foreign objects in the material tray, the three-dimensional structural information of the foreign objects is obtained based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam.

[0043] In an optional implementation, the printing anomaly detection method further includes:

[0044] If a foreign object is detected in the tray, output a prompt message and / or stop printing.

[0045] Secondly, this application provides a 3D printer, which includes:

[0046] A forming platform for attaching printed parts;

[0047] The tray is used to hold printing material and has an opening facing the forming platform;

[0048] The lifting mechanism is connected to the forming platform via a transmission and is used to drive the forming platform closer to or further away from the material tray.

[0049] The illumination mechanism is used to illuminate the printing material in the tray to cure the printing material.

[0050] An ultrasonic testing mechanism is used to generate an ultrasonic detection beam within a material tray;

[0051] The control mechanism is electrically connected to the ultrasonic detection mechanism. The control mechanism is used to enable the ultrasonic detection mechanism to form an ultrasonic detection beam in the material tray according to a pre-configured ultrasonic control strategy; and to determine whether there are foreign objects in the material tray based on the echo of the ultrasonic detection beam.

[0052] In an optional embodiment, the tray includes a bottom wall and a side wall disposed at the edge of the bottom wall, the bottom wall and the side wall together forming a receiving cavity of the tray, and the ultrasonic testing mechanism includes an ultrasonic detection component disposed on the side wall of the tray.

[0053] In an optional embodiment, the ultrasonic detection assembly includes at least one row of first ultrasonic probes for forming a first detection beam propagating in a first direction, and a plurality of first ultrasonic probes belonging to the same row are arranged in a second direction, the first direction being perpendicular to the second direction.

[0054] In an optional embodiment, the ultrasonic detection assembly includes multiple rows of first ultrasonic probes arranged in a third direction, the third direction being perpendicular to the first and second directions.

[0055] In an optional embodiment, the ultrasonic detection assembly further includes at least one row of second ultrasonic probes for forming a second detection beam propagating in a second direction, with multiple second ultrasonic probes belonging to the same row arranged in a first direction.

[0056] In an optional embodiment, the ultrasonic detection assembly includes multiple rows of second ultrasonic probes arranged in a third direction, the third direction being perpendicular to the first and second directions.

[0057] In an optional embodiment, the ultrasonic testing mechanism further includes a longitudinal ultrasonic detection component for forming a longitudinal ultrasonic detection beam propagating upward in a third direction within the tray, wherein the third direction is perpendicular to the first direction and the second direction.

[0058] The control mechanism is also used to obtain the three-dimensional structural information of foreign objects based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam when it is determined that there are foreign objects in the material tray.

[0059] In an optional embodiment, the ultrasonic testing mechanism further includes a scanning drive component, which is connected to the ultrasonic detection component for driving the ultrasonic detection component to move relative to the tray along a preset path.

[0060] In an optional embodiment, a guide rail extending along a preset path is provided on the tray, the ultrasonic detection component slides with the guide rail, and the scanning drive component is used to drive the ultrasonic detection component to move along the guide rail.

[0061] In an optional implementation, the ultrasonic detection component is in close contact with the side wall of the tray; the ultrasonic detection component and the tray are connected by a separate structure or an integrated structure.

[0062] In an optional embodiment, the ultrasonic detection assembly includes ultrasonic probes disposed on at least two opposite sidewalls of the tray, the ultrasonic probes on the opposite sidewalls being arranged in a staggered manner according to the probe beam angle parameters.

[0063] In an optional implementation, the ultrasonic testing mechanism includes an ultrasonic probe, an analog switch, an ultrasonic conversion module, and an MCU main controller;

[0064] One end of the analog switch is electrically connected to the output of the MCU main controller, and the other end of the analog switch is electrically connected to the ultrasonic probe. The MCU main controller is used to send a switch control signal to make the analog switch turn on or off.

[0065] The ultrasonic conversion module is electrically connected to the ultrasonic probe and the MCU main control unit. The ultrasonic conversion module is used to receive high-frequency pulse signals sent by the MCU main control unit so that the ultrasonic probe can convert the high-frequency pulse signals into ultrasonic waves.

[0066] In an optional implementation, the ultrasonic testing mechanism further includes a gain amplification module and an analog-to-digital conversion module that are electrically connected to the MCU main control unit;

[0067] The analog-to-digital converter module is used to receive the echo signal of the ultrasonic probe beam and convert the echo signal into a sampling electrical signal, and then send the sampling electrical signal to the MCU main control.

[0068] The gain amplification module is used to amplify the echo signal of the received ultrasonic probe beam and input it to the analog-to-digital conversion module.

[0069] In an alternative implementation, the 3D printer also includes a display screen for displaying echo images.

[0070] The beneficial effects of the embodiments of this application are as follows:

[0071] The printing anomaly detection method provided in this application is applied to a 3D printer. The 3D printer includes a material tray for containing printing material and a forming platform for attaching the printed part. The printing anomaly detection method includes: according to a pre-configured ultrasonic control strategy, causing an ultrasonic detection mechanism to form an ultrasonic detection beam within the material tray; and determining whether there are foreign objects in the material tray based on the echo of the ultrasonic detection beam. By forming an ultrasonic detection beam within the material tray, the presence of foreign objects can be detected based on the echo of the ultrasonic detection beam. By determining whether there are foreign objects in the material tray, users can easily discover and remove foreign objects in a timely manner, ensuring the normal progress of 3D printing and avoiding poor print quality or even printing failure due to the long-term presence of foreign objects, thus avoiding the waste of a large amount of printing material.

[0072] The 3D printer provided in this application includes a forming platform, a material tray, a lifting mechanism, a lighting mechanism, an ultrasonic detection mechanism, and a control mechanism. The control mechanism is electrically connected to the lifting mechanism, the lighting mechanism, and the ultrasonic detection mechanism. The control mechanism controls the ultrasonic detection mechanism to form an ultrasonic detection beam within the material tray according to a pre-configured ultrasonic control strategy, and determines the presence of foreign objects within the material tray based on the echo of the ultrasonic detection beam. Therefore, the 3D printer provided in this application can improve printing quality and efficiency, and reduce waste of printing materials. Attached Figure Description

[0073] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0074] Figure 1 This is a schematic diagram of the structure of a 3D printer in one embodiment of this application;

[0075] Figure 2 This is a control block diagram of a 3D printer in one embodiment of this application;

[0076] Figure 3 This is a schematic diagram of the arrangement of the ultrasonic probe in the first embodiment of this application;

[0077] Figure 4 This is a schematic diagram of the arrangement of the ultrasonic probe in the second embodiment of this application;

[0078] Figure 5 This is a schematic diagram of the arrangement of the ultrasonic probe in the third embodiment of this application;

[0079] Figure 6 This is a schematic diagram of the arrangement of the ultrasonic probe in the fourth embodiment of this application;

[0080] Figure 7 This is a schematic diagram of the arrangement of the ultrasonic probe in the fifth embodiment of this application;

[0081] Figure 8 This is a schematic diagram of the arrangement of the ultrasonic probe in the sixth embodiment of this application;

[0082] Figure 9 This is a schematic diagram of the structure of an ultrasonic testing mechanism in one embodiment of this application;

[0083] Figure 10 This is a schematic diagram of an ultrasonic probe in one embodiment of this application;

[0084] Figure 11 This is a flowchart of a printing anomaly detection method in one embodiment of this application;

[0085] Figure 12 This is a flowchart illustrating how to determine the presence of foreign objects in a material tray based on the echo of a transverse ultrasonic detection beam, according to one embodiment of this application.

[0086] Icons: 010-3D printer; 100-forming platform; 200-material tray; 300-lifting mechanism; 400-lighting mechanism; 500-ultrasonic testing mechanism; 510-ultrasonic probe; 511-piezoelectric material; 512-transducer wafer; 520-ultrasonic detection assembly; 521-first ultrasonic probe; 522-second ultrasonic probe; 530-longitudinal ultrasonic detection assembly; 540-scanning drive assembly; 541-guide rail; 542-slider; 550-analog switch; 560-ultrasonic conversion module; 570-gain amplification module; 580-analog-to-digital conversion module; 590-MCU main controller; 600-control mechanism; 700-information output device. Detailed Implementation

[0087] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0088] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0089] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0090] In the description of this application, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed during use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0091] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0092] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0093] During the printing process of a photopolymer 3D printer, the printed part may fall into the material tray due to insufficient adhesion, resulting in a printing failure. If the 3D printer cannot detect whether the printed part has fallen, it will continue printing even after this occurs, leading to an unqualified printed product and wasting time and printing material. Some 3D printers use force detection to determine whether the printed part has fallen, but this method has the problem of poor detection effectiveness. Moreover, during the printing process, "external" foreign objects (not printed parts falling from the forming platform) may enter the material tray. These foreign objects can also cause printing abnormalities. The 3D printers in this technology cannot detect these foreign objects, resulting in poor quality printed parts that do not meet product requirements. Therefore, the relevant technologies lack effective means to detect foreign objects in the material tray (including printed parts falling from the forming platform and external foreign objects), resulting in the inability to clean foreign objects in a timely manner, easily leading to poor print quality and wasting a lot of material and time due to printing failures.

[0094] To address at least one deficiency in the aforementioned related technologies, this application provides a printing anomaly detection method and a 3D printer. The method utilizes ultrasonic waves to detect the material tray's accommodating cavity during the printing process, thereby promptly determining whether foreign objects exist within the material tray. This avoids the waste of materials and time, as well as poor printing quality, caused by untimely handling of foreign objects.

[0095] Figure 1 This is a schematic diagram of the structure of a 3D printer 010 in one embodiment of this application; Figure 2 This is a control block diagram of a 3D printer 010 according to one embodiment of this application. Figure 1 and Figure 2 As shown, the 3D printer 010 provided in this embodiment is a photopolymerization printer, specifically an LCD, DLP, or SLA printer. The 3D printer 010 includes a forming platform 100, a material tray 200, a lifting mechanism 300, a lighting mechanism 400, an ultrasonic testing mechanism 500, and a control mechanism 600. The forming platform 100 is used to attach the printed part. The material tray 200 is used to hold the printing material and has an opening facing the forming platform 100. The lifting mechanism 300 is drively connected to the forming platform 100 and is used to drive the forming platform 100 closer to or further away from the material tray 200. The lighting mechanism 400 is used to irradiate the printing material in the material tray 200 to cure the printing material and allow it to adhere to the forming platform 100 or the cured printing material. In this embodiment, the forming platform 100, the material tray 200, and the illumination mechanism 400 are arranged sequentially from top to bottom. The bottom of the material tray 200 is transparent, and the illumination mechanism 400 projects a light beam (such as ultraviolet light UV) upwards, allowing the light beam to enter the receiving cavity of the material tray 200 from the bottom. The printing material is a photosensitive material (such as photosensitive resin), which can undergo solidification under the irradiation of a specific wavelength of light beam, thus becoming a solid slice layer. The 3D printer 010 of this application embodiment forms the printed part by printing layer by layer. By sequentially forming several solid slice layers on the forming platform 100, a printed part formed by stacking several solid slice layers can be obtained. During the 3D printing process, the forming platform 100 gradually rises under the drive of the lifting mechanism 300, while the position where the printing material undergoes solidification remains unchanged (located in the material tray 200). The specific forming method and principle of the photopolymerization printer can be referred to the prior art, and will not be repeated here.

[0096] In this embodiment, the ultrasonic detection mechanism 500 forms an ultrasonic detection beam within the material tray 200. The control mechanism 600 is electrically connected to the lifting mechanism 300, the illumination mechanism 400, and the ultrasonic detection mechanism 500. The control mechanism 600, according to a pre-configured ultrasonic control strategy, causes the ultrasonic detection mechanism 500 to form an ultrasonic detection beam within the material tray 200, and determines the presence of foreign objects within the material tray 200 based on the echo of the ultrasonic detection beam. Therefore, the 3D printer 010 provided in this embodiment can promptly determine the presence of foreign objects in the material tray 200, facilitating timely removal of foreign objects by the user, improving print quality and efficiency, and reducing waste of printing materials and time.

[0097] In this embodiment, the ultrasonic testing mechanism 500 includes an ultrasonic detection component 520, which is used to form an ultrasonic detection beam within the material tray 200. Optionally, the ultrasonic detection beam can propagate in a horizontal direction and avoid the molding platform 100 and the printed parts attached to the molding platform 100.

[0098] Furthermore, the 3D printer 010 provided in this application embodiment also includes an information output device 700, used to output foreign object detection related information and prompt information. For example, the information output device 700 may include a display screen capable of displaying echo intensity information. For instance, the control mechanism 600 displays the image on the display screen after modulating and analyzing the echo signal. In some embodiments, the information output device 700 may also include other devices such as a speaker, buzzer, and indicator light, used to prompt the user with the current detection status (such as the presence of a foreign object) through sound and light, thereby facilitating the user to be aware of the printing abnormality in a timely manner and take appropriate measures.

[0099] Figure 3 This is a schematic diagram of the arrangement of the ultrasonic probe 510 in the first embodiment of this application; Figure 4 This is a schematic diagram showing the arrangement of the ultrasonic probe 510 in the second embodiment of this application. Please refer to... Figures 1 to 4 In this embodiment, the tray 200 includes a bottom wall and a side wall disposed at the edge of the bottom wall. The bottom wall and the side wall together form a receiving cavity of the tray 200. The bottom wall of the tray 200 is transparent, allowing the light beam from the illumination mechanism 400 to pass through. An ultrasonic detection assembly 520 is disposed on the side wall of the tray 200. The ultrasonic detection assembly 520 includes a plurality of ultrasonic probes 510 disposed on the side wall of the tray 200 (see...). Figure 10 ). Figure 3 , Figure 4 The rectangular body in the middle corresponds to the receiving cavity of the material tray 200. The detection sound beam emitted by each ultrasonic probe 510 can be shot from the inner wall of the material tray 200 into the receiving cavity of the material tray 200 to detect foreign objects in the material tray 200.

[0100] Optionally, the ultrasonic detection assembly 520 includes at least one row of first ultrasonic probes 521. The first ultrasonic probes 521 are used to form a first detection sound beam propagating in a first direction. Multiple first ultrasonic probes 521 belonging to the same row are arranged in a second direction, with the first direction perpendicular to the second direction. The tray 200 can be a rectangular tray 200, meaning the bottom wall of the tray 200 is rectangular, and each of the four sides of the bottom wall has a side wall (a total of four side walls). Two side walls are spaced apart in the first direction, and the other two side walls are spaced apart in the second direction. At least one of the two side walls spaced apart in the first direction has at least one row of first ultrasonic probes 521. Figure 3 As shown, a row of first ultrasonic probes 521 is respectively arranged on two sidewalls spaced apart in the first direction of the material tray 200. In alternative embodiments, the first ultrasonic probes 521 may be arranged on only one of the two sidewalls spaced apart in the first direction.

[0101] Optionally, the ultrasonic detection assembly 520 includes multiple rows of first ultrasonic probes 521 arranged in a third-direction orientation, which is perpendicular to the first and second directions. Figure 4 As shown, two rows of first ultrasonic probes 521 are respectively arranged on two side walls of the material tray 200 at intervals in the first direction. The two adjacent rows of first ultrasonic probes 521 can be aligned vertically or staggered. In other optional embodiments, the number of rows of first ultrasonic probes 521 can be further increased as needed.

[0102] exist Figure 3 and Figure 4 In this diagram, the first direction is the front-to-back direction, the second direction is the left-to-right direction, and the third direction is the up-to-down direction. By setting up a row of first ultrasonic probes 521, multiple first detection sound beams can cover a horizontal plane in the cavity of the material tray 200; by setting up multiple rows of first ultrasonic probes 521 arranged in the third direction, foreign objects can be detected in a large spatial range.

[0103] Figure 5 This is a schematic diagram showing the arrangement of the ultrasonic probe 510 in the third embodiment of this application. Figure 5 As shown, the ultrasonic detection assembly 520 may further include at least one row of second ultrasonic probes 522, which are used to form a second detection sound beam propagating in a second direction. Multiple second ultrasonic probes 522 belonging to the same row are arranged in the first direction. Figure 5 As shown, a row of second ultrasonic probes 522 is respectively arranged on two sidewalls spaced apart in the second direction of the material tray 200. In alternative embodiments, the second ultrasonic probes 522 may be arranged on only one of the two sidewalls spaced apart in the second direction.

[0104] In alternative embodiments, the ultrasonic detection assembly 520 may include multiple rows of second ultrasonic probes 522 arranged in a third-direction orientation perpendicular to the first and second directions. Figure 5 In the diagram, the first direction is the front-back direction, the second direction is the left-right direction, and the third direction is the up-down direction.

[0105] It is understandable that if there is a thin foreign object in the material tray 200, such as a small size in the second direction, and if the foreign object is located between the detection sound beams of the two first ultrasonic probes 521, the foreign object cannot effectively reflect the sound waves, and the foreign object may be missed. However, by setting the second ultrasonic probe 522, it can form an interwoven detection sound beam with the first ultrasonic probe 521, thus improving the problem of missed detection in single-direction sound beam detection.

[0106] Optionally, the ultrasonic testing mechanism 500 further includes a longitudinal ultrasonic detection component 530, which is used to form a longitudinal ultrasonic detection beam propagating upwards within the tray 200. When the longitudinal ultrasonic detection component 530 is provided, the control mechanism 600 is also used to obtain three-dimensional structural information of the foreign object, such as its three-dimensional size and shape, based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam, if the presence of a foreign object is determined within the tray 200. The longitudinal ultrasonic detection component 530 can be disposed below the tray 200 or within the bottom wall of the tray 200. The longitudinal ultrasonic detection component 530 may include multiple ultrasonic probes 510 arranged in an array on the same horizontal plane, so that the detection range of the longitudinal ultrasonic detection component 530 covers the entire receiving cavity of the tray 200.

[0107] Optionally, the ultrasonic testing mechanism 500 further includes a scanning drive assembly 540, which is connected to the ultrasonic detection assembly 520 for driving the ultrasonic detection assembly 520 to move relative to the tray 200 along a preset path. Figure 6 This is a schematic diagram of the arrangement of the ultrasonic probe 510 in the fourth embodiment of this application; Figure 7 This is a schematic diagram showing the arrangement of the ultrasonic probe 510 in the fifth embodiment of this application. Figure 6 and Figure 7 As shown, a guide rail 541 extending along a preset path is provided on the material tray 200. The ultrasonic detection component 520 slides with the guide rail 541, and the scanning drive component 540 drives the ultrasonic detection component 520 to move along the guide rail 541. By providing the scanning drive component 540, the ultrasonic detection component 520 can be driven to scan the receiving cavity of the material tray 200, thus requiring fewer ultrasonic probes 510 to detect foreign objects within the material tray 200. Specifically, the track is set on two side walls of the material tray 200 spaced apart in a first direction, and the track extends along a second direction, meaning the preset direction is the second direction. Figure 6In this embodiment, multiple ultrasonic probes 510 of the ultrasonic detection assembly 520 are arranged at intervals along a second direction (left-right direction) on the slider 542, and the slider 542 is slidably engaged with the guide rail 541. Figure 7 In this embodiment, multiple ultrasonic probes 510 of the ultrasonic detection component 520 are arranged at intervals on the slider 542 along the third direction (vertical direction). When the slider 542 moves along the guide rail 541, the ultrasonic detection component 520 can scan a large spatial volume at once, thus improving the detection efficiency.

[0108] It should be understood that, in other alternative embodiments, the preset path is not limited to... Figure 6 , Figure 7 In this embodiment, the straight line segment along the second direction is used. In other embodiments, the preset path can be a C-shape, S-shape, or other path structure. Correspondingly, the extension direction of the guide rail 541 should match the preset path.

[0109] Figure 8 This is a schematic diagram showing the arrangement of the ultrasonic probe 510 in the sixth embodiment of this application. Figure 8 As shown, in some embodiments, multiple ultrasound probes 510 may not be synchronously driven by the scanning drive assembly 540 on the same slider 542. Instead, multiple ultrasound probes 510 may be slidably engaged with the guide rail 541 and move independently along the guide rail 541.

[0110] In the above embodiments, the ultrasonic detection assembly 520 is described as being disposed on the side wall of the tray 200. When ultrasonic probes 510 are disposed on two opposite side walls of the tray 200, the ultrasonic probes 510 on the opposite side walls can be staggered according to the probe beam angle parameters, so that the detection sound beam can be evenly distributed in the receiving cavity of the tray 200. In addition, the ultrasonic probes 510 can be disposed on the inner or outer surface of the side wall of the tray 200. The ultrasonic probes 510 are in close contact with the side wall, that is, there is no air gap between them, which can avoid the impact of sound energy loss caused by the air interface on the accuracy of the detection results. The number of ultrasonic probes 510 can be determined according to the size of the tray 200 (such as the length of the side wall of the tray 200) and the sound beam angle of the ultrasonic probes 510. In other optional embodiments, the shape of the tray 200 can be non-rectangular, such as circular; in this case, each ultrasonic probe 510 of the ultrasonic detection assembly 520 can be disposed around the side wall of the tray 200. The ultrasonic probes 510 can also be arranged in a different pattern or irregularly, depending on the requirements, instead of following an array.

[0111] The ultrasonic probe 510 and the material tray 200 can be an integrated structure, meaning the ultrasonic probe 510 and the material tray 200 are not detachable and are assembled as a single component in the 3D printer 010. Alternatively, the ultrasonic probe 510 and the material tray 200 can be a separate structure, meaning they are detachably connected. The separate structure offers greater flexibility. When installing the ultrasonic probe 510, its installation position and number can be freely adjusted according to the size of the material tray 200, the parameters of the ultrasonic probe 510, the characteristics of the printing material, and the preset ultrasonic detection resolution. Furthermore, the ultrasonic probe 510 is not bound to the material tray 200, allowing for independent replacement of either the material tray 200 or the ultrasonic probe 510, thereby reducing the manufacturing cost of the printing material tray 200. In contrast, with the integrated structure, when it is necessary to replace the material tray 200 or the ultrasonic probe 510, it can be replaced directly as a whole without reinstalling or even adjusting the position of the probe after replacement, which is highly convenient. The integrated structure can more easily achieve a tight contact between the ultrasonic probe 510 and the side wall of the material tray 200, and has a low dependence on the use of coupling agent to isolate the air between the ultrasonic probe 510 and the side wall of the material tray 200, or even without the use of coupling agent.

[0112] In alternative embodiments, the ultrasonic detection component 520 may also be disposed outside the tray 200 and spaced apart from the outer surface of the sidewall of the tray 200. In this case, the ultrasonic detection beam should penetrate the sidewall of the tray 200 to detect foreign objects within the tray 200.

[0113] Optionally, the ultrasonic detection mechanism 500 in this embodiment has a resolution of 0.1 μm to 1 cm, meaning it can detect foreign objects with a minimum size of less than 1 mm. In this embodiment, when there are multiple foreign objects in the tray 200, the ultrasonic detection mechanism 500 can detect the number of foreign objects. Specifically, the resolution of the ultrasonic detection mechanism 500 includes lateral resolution and longitudinal resolution. Lateral resolution refers to the minimum distance between two foreign objects on an interface perpendicular to the sound beam, and longitudinal resolution refers to the minimum distance between two foreign objects located on the ultrasonic axis. Optionally, in this embodiment, the ultrasonic probe 510 of the ultrasonic detection mechanism 500 has a lateral resolution of less than 1 mm and a longitudinal resolution of less than 1 mm.

[0114] Optionally, the frequency range of the ultrasonic probe beam and the longitudinal ultrasonic probe beam is not less than 20 kHz, for example, 20 kHz to 200 MHz. The frequency of the ultrasonic probe beam and the longitudinal ultrasonic probe beam can be determined based on at least one of the characteristics of the printing material (such as viscosity, density, solid-liquid density difference), the structure of the tray 200 (such as shape and size), and the required resolution.

[0115] First, the speed and impedance of ultrasound vary in different media. For example, the higher the density of the medium, the faster the ultrasound propagates. In actual 3D printing, the propagation speed of the ultrasonic probe beam differs between liquid and solid printing materials (such as a portion of the printed part falling from the forming platform 100 and becoming a foreign object), resulting in different echo delays. The frequency of the ultrasound can be matched according to the type and characteristics of the printing material.

[0116] Secondly, because ultrasound has a beam-like property—that is, when the ultrasonic frequency is high and the radiating surface is larger than its wavelength—the sound beam emitted from the sound source will first propagate in a straight line for a certain distance before diverging at a certain angle. Therefore, to ensure that the ultrasonic beam can propagate in a straight line without diverging during its propagation within the material tray 200, an appropriate frequency needs to be selected based on the size of the material tray 200 to avoid divergence during propagation, which would result in poor received echo signals.

[0117] Furthermore, the lateral resolution of the ultrasonic testing mechanism 500 is determined by the beam diameter; the longitudinal resolution is mainly determined by the pulse width of the ultrasonic wave. The longitudinal resolution is approximately half the pulse width, which is primarily determined by the pulse duration and the ultrasonic velocity. One factor affecting the pulse duration is the ultrasonic frequency; higher frequencies result in shorter pulse durations, smaller pulse widths, and greater longitudinal resolution, and vice versa. While a higher frequency for the ultrasonic probe 510 leads to higher resolution and clearer detection of foreign objects, higher frequencies also result in more significant attenuation and a substantial decrease in penetration depth. Therefore, a balance must be struck between the frequency of the ultrasonic probe 510, the size of the material tray 200, and the minimum size of the foreign object to be detected to achieve the optimal testing results.

[0118] As a physical phenomenon, when an ultrasonic wave encounters a foreign object with a wavelength similar to its own, it can bypass the edge of the foreign object and continue its propagation, maintaining its direction of transmission after bypassing the object. The diffraction of the sound beam is related to the relative size of the foreign object (D) and the wavelength (λ) of the sound beam. When D is much smaller than λ, the diffraction is strong and the reflection is weak, resulting in a very weak echo from the foreign object and making it easy to miss detections. Conversely, when D is much larger than λ, the reflection is strong and the diffraction is weak, resulting in almost complete emission of the sound wave. Therefore, when selecting an ultrasonic probe 510, the required resolution for ultrasonic testing must be considered, meaning the ultrasonic wave length must be much smaller than the diameter of the foreign object being detected to avoid false positives or false negatives due to the diffraction characteristics of the ultrasonic wave.

[0119] Optionally, the power of the ultrasonic probe 510 in this embodiment is not less than 100MW, which can be determined based on the characteristics of the liquid printing material (such as viscosity, thermal conductivity, and temperature), the material of the probe and the tray 200, and the size of the tray 200. The detection sound beam attenuates during propagation; that is, the diffusion of the detection sound beam at different acoustic resistance interfaces causes reflection / refraction, weakening the sound energy in the direction of the main sound beam. In this embodiment, the detection sound beam may undergo multiple attenuations during foreign object detection. For example, there is loss at the interface between the ultrasonic probe 510 and the liquid printing material, loss at the interface between the liquid printing material and the solid foreign object, and loss at the interface between the liquid printing material and the tray 200. In this embodiment, the probe power is sufficiently large to overcome the attenuation loss of the sound beam energy at different medium interfaces, thereby ensuring that the detection sound beam can be reflected back and received during propagation in the liquid printing material, thus enabling detection to be completed.

[0120] In this embodiment, the size of the ultrasonic probe 510 can be determined based on the structure of the tray 200 (such as its shape and size) and the beam characteristics of the ultrasonic waves. Optionally, firstly, the length / width of the tray 200 should be less than the length of the non-diffusion region of the sound beam in the detection direction. Secondly, it is necessary to ensure that the sound beam emitted by the ultrasonic probe 510 operates within the non-diffusion region to avoid the diffusion effect of the sound beam in the diffusion region affecting the reflected echo and improving the accuracy of ultrasonic detection.

[0121] Figure 9 This is a schematic diagram of the architecture of an ultrasonic testing mechanism 500 in one embodiment of this application. Figure 9 As shown, the ultrasonic testing mechanism 500 includes an ultrasonic probe 510, an analog switch 550, an ultrasonic wave conversion module 560, and an MCU main controller 590, which are connected in sequence. The ultrasonic probe 510 can be mounted on the material tray 200. The MCU main controller 590 can be the main controller of the 3D printer 010, or another main controller connected to the main controller of the 3D printer 010. One end of the analog switch 550 is electrically connected to the output terminal of the MCU main controller 590, and the other end is electrically connected to the ultrasonic probe 510. The MCU main controller 590 is used to send a switch control signal to turn the analog switch 550 on or off. The ultrasonic wave conversion module 560 is electrically connected to the ultrasonic probe 510 and the MCU main controller 590. The ultrasonic wave conversion module 560 is used to receive the high-frequency pulse signal sent by the MCU main controller 590, so that the ultrasonic probe 510 converts the high-frequency pulse signal into ultrasonic waves.

[0122] In this embodiment, the analog switch 550 is a multi-channel high-voltage analog switch circuit, which includes multiple parallel-connected analog switch branches. Its switch control terminal is used to connect to the output terminal of the ultrasound host signal. During the ultrasound signal transmission phase, the ultrasound host sends a switch control signal to control the corresponding analog switch branch to conduct. The electrical signal emitted by the ultrasound host is directly applied to the transducer chip 512 of the ultrasound probe 510 through the high-voltage analog switch circuit.

[0123] The ultrasonic transceiver module 560 may include a high-speed pulse T / R IC, which is a high-voltage electrical signal to ultrasonic wave conversion chip. During the ultrasonic signal transmission stage, the ultrasonic host sends a high-frequency pulse signal, which is then applied to the pulse transceiver IC after passing through a boost circuit. The electrical signal is converted into high-frequency ultrasonic waves by the ultrasonic probe 510. At the same time, the chip can also receive the ultrasonic waves reflected back after encountering residue and convert them into high-frequency electrical pulse signals for subsequent signal analysis and processing by the MCU main controller 590.

[0124] The ultrasonic testing mechanism 500 also includes a gain amplification module 570 and an analog-to-digital conversion module 580 that are electrically connected to the MCU main control unit. The analog-to-digital conversion module 580 is used to receive the echo signal of the ultrasonic probe beam and convert the echo signal into a sampling electrical signal, and send the sampling electrical signal to the MCU main control unit 590. The gain amplification module 570 is used to amplify the received echo signal of the ultrasonic probe beam and input it to the analog-to-digital conversion module 580.

[0125] The gain amplification module 570 may include a VGA chip. A VGA is a variable gain amplifier circuit. In this embodiment, since the voltage range of the reflected foreign object wave varies from a few millivolts to several hundred millivolts, the signal amplification circuit must have the ability to adjust the amplification factor as needed, and the gain adjustment range for ultrasonic detection applications needs to reach 60dB. In practical applications, a VGA chip with sufficient amplification gain needs to be selected according to requirements.

[0126] The analog-to-digital converter module 580 may include a high-speed analog-to-digital converter chip. In this embodiment, the high-speed analog-to-digital converter chip is used to receive ultrasonic signals reflected back from foreign objects, sample them, and convert them into electrical signals for output. In ultrasonic applications, the analog-to-digital converter module 580 generally uses a multi-channel high-speed chip with a sampling rate between 50 and 100 MHz and a bit width between 8 and 12 bits.

[0127] The ultrasonic probe 510 in this embodiment (including the first ultrasonic probe 521, the second ultrasonic probe 522, and the ultrasonic probe in the longitudinal ultrasonic detection assembly 530) can be a single-chip probe or a multi-chip probe. A single-chip probe contains only one transducer chip, which is used to both generate and receive high-frequency ultrasonic beams. A multi-chip probe contains a pair or more transducer chips, where one chip in a pair is used to emit sound waves and the other is used to receive them. A phased array probe, as a type of multi-chip probe, generally contains a transducer assembly containing several to hundreds of small transducer chips, each of which can be individually triggered. The arrangement of these multiple small chips in the transducer assembly includes, but is not limited to, a strip (linear array), a ring (ring array), a circular matrix (circular array), or other shapes. Figure 10 This is a schematic diagram of an ultrasonic probe 510 in one embodiment of this application. Figure 10 As shown, the ultrasonic probe 510 is a multi-element probe, comprising a piezoelectric material 511 and multiple transducer wafers 512 disposed on the piezoelectric material 511, forming a wafer array. The phased array probe utilizes the phase adjustment principle of wave physics, altering the time (delay) between a series of ultrasonic beam pulses. This allows the individual wavefronts generated by each wafer in the array to combine, controllably increasing or decreasing energy, thereby achieving control and shaping of the ultrasonic beam. To achieve this function, pulses are emitted from the wafers of the ultrasonic probe 510 with extremely small time differences, each group containing several to dozens of wafers. By lengthening the aperture, unwanted beam diffusion effects are reduced, resulting in stronger focusing and effectively improving detection sensitivity.

[0128] In this proposal, based on the parameter characteristics of the ultrasonic probe 510 and the geometry and acoustic properties of the material under test (resin-printed part), the MCU main controller 590 transmits pulses to each group of wafers with a specific delay time, thereby generating the desired sound beam shape. This pulse transmission sequence is pre-programmed and stored in the device's operating system. After the command is issued, the probe emits a series of individual wavefronts within the material under test. These converging wavefronts are strengthened at some locations and weakened at others, forming a single dominant wavefront. This dominant wavefront propagates within the material under test and, like conventional ultrasonic testing beams, generates echoes when encountering cracks, discontinuities, bottom surfaces, and other material boundaries. The sound beam can be passively deflected at different angles and focal lengths. The ultimate goal is to enable a single probe assembly to complete the detection of the entire test piece through a series of different perspectives, thereby obtaining precise details or three-dimensional imaging information of the test object.

[0129] In this embodiment of the application, the echo data of the probe beam will be based on information such as time and waveform obtained from the processed RF waveform. The way to obtain this information can be presented in one or more scanning methods, such as A-type scanning, B-type scanning, C-type scanning or S-type scanning.

[0130] A-mode scanning is a simple RF wave display that obtains the time and amplitude of the ultrasonic signal. It is typically obtained by acquiring the echo of a cylindrical acoustic beam emitted from a single-crystal probe. B-mode scanning displays an image of the cross-sectional profile of a vertical slice of the object under test, showing the depth of the reflector relative to its linear position. Compared to A-mode scanning, B-mode scanning requires the ultrasonic probe 510 to move the scanning beam in a specific direction along a selected axis of the object under test when storing the relevant echo data. C-mode scanning is a two-dimensional data image of a planar view of the object under test. Each point of the object under test is mapped to an xy position in the image, and the amplitude of different echoes can be represented by different colored images. For single-crystal probes, the probe must be moved and scanned on the sample under test in an xy raster scanning mode; if a phased array probe system is used, the ultrasonic probe 510 can be physically displaced along one axis while the acoustic beam is electronically scanned along the other axis. S-mode scanning represents a two-dimensional cross-sectional view obtained from a series of A-mode scans, the former having already acquired information on the time delay and refraction angle of the ultrasonic beam. The sound beam forms an approximately fan-shaped cross-sectional information after sweeping through a series of angles. In the embodiments of this application, all four scanning methods can satisfy the detection of foreign objects in the material tray 200 during the 3D printing process, and different scanning methods can be selected according to the required detection accuracy.

[0131] Figure 11 This is a flowchart of a printing anomaly detection method in one embodiment of this application. Figure 11 As shown, the printing anomaly detection method provided in this application embodiment can be applied to the 3D printer 010 provided in the above embodiments of this application. The printing anomaly detection method includes:

[0132] Step S100: According to the pre-configured ultrasonic control strategy, the ultrasonic detection mechanism forms an ultrasonic detection beam within the material tray.

[0133] Taking the 3D printer 010 provided in this embodiment as an example, the control mechanism 600 can control the ultrasonic detection component 520 of the ultrasonic detection mechanism 500 to form an ultrasonic detection beam. In this embodiment, the material tray 200 includes a bottom wall and side walls disposed at the edge of the bottom wall. The bottom wall and the side walls together form a receiving cavity of the material tray 200, and the ultrasonic detection beam is transmitted from one side wall of the material tray 200 to the opposite side wall. Figures 3 to 8 For example, in the embodiment, the material tray 200 is a rectangular material tray, and the ultrasonic detection beam always extends along the length or width direction of the material tray 200.

[0134] Furthermore, the ultrasonic detection beam includes at least one row of first detection beams propagating in a first direction, and multiple first detection beams belonging to the same row are arranged in a second direction, with the first direction perpendicular to the second direction. This arrangement of the ultrasonic detection beams can be achieved by… Figure 3 Implementation example. Further, the ultrasonic detection beam includes multiple rows of first detection beams arranged in a third direction, the third direction being perpendicular to the first and second directions. For example... Figure 4 As shown in the embodiment, two rows of first ultrasonic probes 521 arranged in a third-direction upward direction can be used to form two rows of first detection sound beams arranged in a third-direction upward direction. Optionally, the first direction and the second direction can be two horizontal directions that are perpendicular to each other, and the third direction can be a vertical direction (i.e., the direction of gravity). When the tray 200 is normally placed, its bottom is horizontal and its opening is vertically upward.

[0135] By forming multiple first detection sound beams, the first detection sound beams can be distributed as widely as possible in the space of the material tray 200, thereby reducing detection blind spots and reducing missed detections. Optionally, when the material tray 200 is provided with first ultrasonic probes 521 on two opposite sidewalls in the first direction, the first detection sound beams emitted from the two sidewalls can be staggered to make the distribution of the first detection sound beams more uniform.

[0136] Furthermore, the ultrasonic detection beam may also include at least one row of second detection beams propagating in the second direction, with multiple second detection beams belonging to the same row arranged in the first direction, such as... Figure 5 As shown. By forming at least one row of second detection beams, they can interweave with the first detection beam, avoiding the problem that thinner foreign objects are difficult to detect in a single detection direction, thus improving detection accuracy and reducing false detections and missed detections. Optionally, the ultrasonic detection beam includes multiple rows of second detection beams arranged in a third direction, which is perpendicular to the first and second directions.

[0137] Optionally, the ultrasonic control strategy is configured to control multiple ultrasonic probes to sequentially and gradually form ultrasonic detection beams or to simultaneously form ultrasonic detection beams. In other words, each ultrasonic probe 510 in the ultrasonic detection assembly 520 can emit ultrasonic detection beams simultaneously or sequentially. For example, in one specific embodiment, each row of first ultrasonic probes 521 emits a row of first detection beams sequentially, and then each row of second ultrasonic probes 522 emits a row of second detection beams sequentially. When forming each row of first or second detection beams, each probe can emit detection beams simultaneously or sequentially.

[0138] Optionally, the ultrasonic control strategy is also configured to control the ultrasonic probe beam to scan along a preset path within the material tray 200. Figures 6 to 8 In one embodiment, the control mechanism 600 can control the scanning drive unit to move at least a portion of the ultrasonic probes 510 of the ultrasonic detection assembly 520, thereby changing the position of the ultrasonic detection beam. This method can reduce the number of ultrasonic probes 510 in the ultrasonic detection assembly 520, and ensure that as many positions as possible in the receiving cavity of the tray 200 can be detected through scanning. The preset scanning path can be a straight line segment (such as along one of the first, second, and third directions), or other shaped paths such as C-shapes or S-shapes.

[0139] The ultrasonic control strategy is also configured to determine the frequency of the ultrasonic detection beam based on at least one of the characteristics of the printing material, the structural features of the tray, and the required resolution. Optionally, the frequency range of the ultrasonic detection beam is 20kHz to 200MHz. It is understood that the selection of the ultrasonic detection beam frequency affects the detection accuracy and effect. A suitable ultrasonic detection beam frequency should be selected based on relevant factors such as the size of the foreign object to be detected, the tray size, and the physical properties of the printing material. For a detailed explanation of the principle, please refer to the previous section on the frequency of the detection beam.

[0140] Step S200: Determine whether there are foreign objects in the material tray based on the echo of the ultrasonic detection beam.

[0141] Figure 12 This is a flowchart illustrating how the presence of foreign objects in a material tray 200 is determined based on the echo of an ultrasonic detection beam, according to one embodiment of this application. Figure 12 As shown in the embodiments of this application, step S200 may specifically include:

[0142] Step S210: Obtain the echo delay time of the ultrasonic probe beam.

[0143] During the propagation of the sound beam, if it encounters an interface with two different acoustic impedances, a portion of the sound beam returns to the former medium, i.e., reflection occurs at the interface. Therefore, the sound beam will be reflected when it passes through interfaces such as the material tray 200-liquid printing material and the liquid printing material-solid foreign object, generating an echo signal that can be received by the ultrasonic probe 510. Specifically, this step involves calculating the delay time and intensity of the echo received by the ultrasonic probe 510 of the transverse ultrasonic detection component relative to the emitted sound beam.

[0144] Step S220: Determine whether the echo delay time is within the preset delay threshold range;

[0145] If yes, proceed to step S230: determine that there are no foreign objects in the tray; otherwise, proceed to step S240: determine that there are foreign objects in the tray.

[0146] Specifically, during ultrasonic testing, the ultrasonic probe 510 emits one or more sets of ultrasonic waves in a certain direction. The non-liquid foreign matter affecting printing within the liquid printing material in the tray 200 can be determined by monitoring the echo delay time. Since the size of the tray 200 is fixed, with the same amount of printing material, the echo delay time is fixed if there is no foreign matter in the tray 200. However, if there is foreign matter in the tray 200, the echo delay time of the ultrasonic probe 510 corresponding to the detection beam covering the foreign matter will have a certain deviation. Therefore, it is possible to determine whether a foreign matter exists, its location, and even its size. Therefore, step S200 may include: acquiring the echo delay time of the ultrasonic detection beam; comparing the echo delay time with a preset standard delay time for no residue or foreign matter to obtain a time deviation value; determining whether the time deviation value is within a preset time threshold range; if so, determining that there is no foreign matter in the tray; otherwise, determining that there is foreign matter in the tray.

[0147] Optionally, the preset threshold range is a threshold range with a reference value as the midpoint. The reference value is the echo delay time of the ultrasonic detection beam when there are no foreign objects in the material tray 200. It can be understood that if there are no foreign objects in the material tray 200, theoretically the echo delay time should be equal to the reference value. Considering the system error of the detection, it can be considered that there are no foreign objects in the material tray 200 when the echo delay time deviates within a certain range near the reference value. Therefore, in this embodiment, the preset threshold range is set to a threshold range with the reference value as the midpoint. In other optional embodiments, the setting method of the preset threshold range can be adjusted according to the actual situation.

[0148] The ultrasonic probe 510 can emit ultrasonic waves after receiving an excitation pulse. At the same time, the ultrasonic probe 510 is controlled by a focusing delay circuit to achieve acoustic focusing of the detection sound beam. After a period of delay, the ultrasonic probe 510 receives the reflected echo signal. After signal processing such as filtering and logarithmic amplification, the signal is converted into a digital signal by the DSC circuit and compared with the preset threshold range stored in the control mechanism 600 to determine whether there are foreign objects in the material tray 200.

[0149] Optionally, step S200 includes: acquiring echo intensity information of the ultrasonic detection beam; and determining whether there are foreign objects in the tray based on the echo intensity information.

[0150] Furthermore, the presence of foreign objects in the tray is determined based on the echo intensity information, including:

[0151] When the echo intensity information is strong, it is determined that there is a solid foreign object; when the echo intensity information is weak, it is determined that there is a semi-solidified foreign object; when the echo intensity information is omnipresent, it is determined that there is no foreign object.

[0152] Optionally, the printing anomaly detection method further includes: controlling the information output device 700 to output the echo intensity information of the ultrasonic probe beam. By outputting the echo intensity information of the ultrasonic probe beam through the information output device 700, users can intuitively understand the echo intensity during the current detection process.

[0153] Optionally, after acquiring the echo intensity information of the ultrasonic probe beam, the printing anomaly detection method further includes:

[0154] The echo intensity information is converted into an echo image; the presence of foreign objects in the tray is determined based on the echo image, and the echo image is displayed; different echo intensity information corresponds to different grayscale values ​​in the echo image.

[0155] Specifically, when the information output device 700 is a display screen, the step of controlling the information output device 700 to output the echo intensity information of the ultrasonic detection beam may include: controlling the information output device 700 to display an echo intensity image of the ultrasonic detection beam, wherein the grayscale value of the echo intensity image is positively or negatively correlated with the echo intensity of the ultrasonic detection beam. The grayscale value ranges from 0 to 255, where a grayscale value of 0 represents black and a grayscale value of 255 represents white.

[0156] In this embodiment, the user can determine whether there are foreign objects in the tray 200 through a visualized image. Specifically, the control mechanism 600 (such as a CPU) performs further image processing on the echo converted into a digital signal. The control mechanism 600 forms grayscale according to certain rules (algorithms), and then synthesizes it together with the chart forming circuit and the measurement circuit to present a visualized image on the display screen. The user can determine whether there are foreign objects based on the grayscale of the image on the display screen.

[0157] For example, determining the presence, type, and shape of foreign objects based on echo intensity images follows the following rules:

[0158] 1) White represents strong echo. When ultrasound encounters solid foreign objects (such as hard objects like fallen solidified printed parts), it will be almost completely reflected. The ultrasound probe 510 receives almost all of the emitted sound beam, so it appears as white (strong echo) in the image.

[0159] 2) Light gray represents weak echoes. When ultrasound waves encounter semi-solidified, soft foreign objects, they are partially reflected. The ultrasound probe 510 receives part of the sound beam, which is therefore displayed as light gray (weak echo) in the image.

[0160] 3) Black represents no echo. When the ultrasonic wave encounters the liquid printing material in the tray 200, it will pass through almost entirely without reflection. The ultrasonic probe 510 cannot receive the emitted sound beam, so it appears as black (no echo) in the image.

[0161] It should be understood that in the above example, the grayscale value and the echo intensity are positively correlated. In other embodiments, the grayscale value and the echo intensity may also be negatively correlated, that is, white on the image represents no echo, and black on the image represents strong echo.

[0162] In this embodiment, if a foreign object is detected in the material tray 200, step S300 can be further executed: outputting a prompt message and / or stopping printing. The prompt message can be an image, such as displaying a message about the presence of a foreign object on a screen; it can also be an audio message, emitting a sound warning if the information output device 700 includes a speaker or buzzer; or it can be a flashing message, such as flashing an indicator light or displaying a specified color to alert the user to the presence of a foreign object if the information output device 700 includes an indicator light. When a foreign object is detected in the material tray 200, the control mechanism 600 can choose to stop the current printing process to avoid producing substandard products, thus preventing waste of printing materials and time and improving printing efficiency.

[0163] If it is determined that there are no foreign objects in the material tray 200, it can be further determined whether the actual number of printed layers is equal to the total number of slice layers of the model. If so, printing ends; otherwise, the next foreign object detection is performed or the next foreign object detection is performed after the set conditions are met (such as the printing of the preset number of layers is completed).

[0164] In this embodiment, the 3D printer 010 prints layer by layer to form a printed part on the forming platform 100. Therefore, the ultrasonic control strategy in step S100 can be configured as follows: after the 3D printer prints a preset target number of layers, an ultrasonic detection command is executed to cause the ultrasonic detection mechanism to form an ultrasonic detection beam within the material tray. The target number of layers can be manually set by the user or directly recorded in the 3D printing data.

[0165] The target layer number refers to the number of layers for ultrasonic testing, meaning that ultrasonic testing begins after the printer has printed the target number of layers. The preset layer number can be set according to requirements, such as 10, 50, 100, 200, 500 layers, etc. The preset target layer interval can be set to a constant value n. For example, if 3D printer 010 performs foreign object detection every n layers printed, with n=10, the target layer number would be 10, 20, 30, 40, etc. The target layer interval can also be set to a variable value, such as changing according to a certain pattern. For example, for the first 100 layers, the foreign object detection function can be activated every 10 layers printed; and after printing 100 layers, it can be activated every 100 layers printed. This is because the problem of printed parts falling off is more likely to occur in the initial stage of printing, therefore the detection and judgment frequency is relatively high in the initial stage of printing, and relatively low in the later stages of printing.

[0166] In other embodiments, detection and judgment can be performed in real time without setting a preset number of layers. In such embodiments, the ultrasonic control strategy can be configured to control the ultrasonic detection mechanism 500 to continuously emit ultrasonic detection beams after the 3D printer is started, and the foreign object situation can be analyzed by combining the detection results of the ultrasonic detection mechanism 500 with the operating stage of the 3D printer 010.

[0167] Furthermore, the printing anomaly detection method may also include: forming a longitudinal ultrasonic detection beam within the material tray 200; and, if it is determined that there is a foreign object within the material tray 200, obtaining the three-dimensional structural information of the foreign object based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam.

[0168] Specifically, the control mechanism 600 can control the longitudinal ultrasonic detection component 530 to emit a longitudinal ultrasonic detection beam. In combination with the ultrasonic detection beam, the control mechanism 600 can further calculate the three-dimensional structural information of the foreign object, such as the three-dimensional size and shape of the foreign object, based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam.

[0169] The 3D printer 010 and printing anomaly detection method provided in this application have the following advantages:

[0170] 1. By detecting foreign objects within the material tray 200 before and during 3D printing using a sound beam, the printing process can be terminated in time before printing fails, avoiding the discovery of printing failure due to foreign objects only after printing is completed, thus saving time and material costs.

[0171] 2. Precise control is achieved for ultrasonic testing of 3D printers, thereby controlling the propagation angle and depth of the ultrasonic probe beam, and thus achieving accurate analysis and processing of the received echoes, resulting in high accuracy of the test results.

[0172] 3. By adjusting the frequency and number of ultrasonic probes 510, accurate identification and location of foreign objects of different shapes can be achieved.

[0173] 4. The information output device 700 outputs visualized detection results (such as grayscale images), allowing for a simple and intuitive observation of the differences and changes in the echoes, making it easy to make judgments.

[0174] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for detecting printing anomalies, applied to a 3D printer, the 3D printer comprising a tray for receiving printing material, an ultrasonic detection mechanism, and a forming platform for attaching printed parts, characterized in that, The material tray includes a bottom wall and a side wall disposed at the edge of the bottom wall, the bottom wall and the side wall together forming a receiving cavity of the material tray. The ultrasonic testing mechanism includes an ultrasonic detection component disposed on the side wall of the material tray. The printing anomaly detection method includes: According to the pre-configured ultrasonic control strategy, the ultrasonic detection mechanism forms an ultrasonic detection beam that propagates in the horizontal direction within the material tray. The presence of foreign objects in the tray is determined based on the echo of the ultrasonic detection beam.

2. The printing anomaly detection method according to claim 1, characterized in that, The ultrasonic control strategy is configured as follows: After the 3D printer prints the preset target number of layers, an ultrasonic testing command is executed to cause the ultrasonic testing mechanism to form an ultrasonic detection beam within the material tray; or After the 3D printer is started, the ultrasonic detection mechanism continuously generates ultrasonic detection beams.

3. The printing anomaly detection method according to claim 1, characterized in that, The ultrasonic testing mechanism includes multiple ultrasonic probes, and the ultrasonic control strategy is configured as follows: Multiple ultrasonic probes are controlled to form ultrasonic detection beams sequentially or synchronously.

4. The printing anomaly detection method according to claim 1, characterized in that, The ultrasonic control strategy is also configured to: The ultrasonic probe beam is controlled to scan along a preset path within the material tray.

5. The printing anomaly detection method according to claim 1, characterized in that, The ultrasonic control strategy is also configured to: The frequency of the ultrasonic detection beam is determined based on at least one of the characteristics of the printing material, the structural features of the tray, and the required resolution and saturation.

6. The printing anomaly detection method according to claim 5, characterized in that, The frequency range of the ultrasonic detection beam is 20kHz~200MHz.

7. The printing anomaly detection method according to claim 1, characterized in that, The step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes: Obtain the echo delay time of the ultrasonic detection beam; Determine whether the echo delay time is within a preset delay threshold range; If so, it is determined that there are no foreign objects in the tray; Otherwise, it is determined that there are foreign objects in the tray.

8. The printing anomaly detection method according to claim 1, characterized in that, The step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes: The echo delay time of the ultrasonic detection beam is obtained, and the echo delay time is compared with the preset standard delay time without residue or foreign matter to obtain the time deviation value. Determine whether the time deviation value is within a preset time threshold range; If so, it is determined that there are no foreign objects in the tray; Otherwise, it is determined that there are foreign objects in the tray.

9. The printing anomaly detection method according to claim 1, characterized in that, The step of determining whether there are foreign objects in the tray based on the echo of the ultrasonic detection beam includes: Obtain the echo intensity information of the ultrasonic detection beam; The presence of foreign objects in the tray is determined based on the echo intensity information.

10. The printing anomaly detection method according to claim 9, characterized in that, Determining whether there are foreign objects in the tray based on the echo intensity information includes: When the echo intensity information is a strong echo, it is determined that there is a solid foreign object; When the echo intensity information is weak echo, it is determined that there is a semi-solidified foreign object; When the echo intensity information is no echo, it is determined that there is no foreign object.

11. The printing anomaly detection method according to claim 10, characterized in that, After acquiring the echo intensity information of the ultrasonic probe beam, the method further includes: The echo intensity information is converted into an echo image; The presence of foreign objects in the tray is determined based on the echo image, and the echo image is displayed; wherein, different echo intensity information corresponds to different grayscale values ​​in the echo image.

12. The printing anomaly detection method according to any one of claims 1 to 11, characterized in that, The printing anomaly detection method further includes: A longitudinal ultrasonic detection beam is formed within the material tray; If it is determined that there is a foreign object in the tray, the three-dimensional structural information of the foreign object is obtained based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam.

13. The printing anomaly detection method according to any one of claims 1 to 11, characterized in that, The printing anomaly detection method further includes: If a foreign object is detected in the tray, a prompt message will be output and / or printing will be stopped.

14. A 3D printer, characterized in that, The 3D printer includes: A forming platform for attaching printed parts; A tray for holding printing material, the tray having an opening facing the forming platform; wherein the tray includes a bottom wall and a side wall disposed at the edge of the bottom wall, the bottom wall and the side wall together forming a receiving cavity of the tray; A lifting mechanism is connected to the forming platform for driving the forming platform closer to or away from the material tray. An illumination mechanism is used to irradiate the printing material in the tray to cure the printing material. An ultrasonic testing mechanism includes an ultrasonic detection component disposed on the side wall of the material tray, the ultrasonic detection component being used to form an ultrasonic detection beam that propagates in a horizontal direction within the material tray; A control mechanism is electrically connected to the ultrasonic detection mechanism. The control mechanism is used to enable the ultrasonic detection mechanism to form the ultrasonic detection beam in the material tray according to a pre-configured ultrasonic control strategy; and to determine whether there are foreign objects in the material tray based on the echo of the ultrasonic detection beam.

15. The 3D printer according to claim 14, characterized in that, The ultrasonic detection assembly includes at least one row of first ultrasonic probes, which are used to form a first detection sound beam propagating in a first direction. A plurality of the first ultrasonic probes belonging to the same row are arranged in a second direction, which is perpendicular to the second direction.

16. The 3D printer according to claim 15, characterized in that, The ultrasonic detection assembly includes multiple rows of the first ultrasonic probes arranged in a third direction, the third direction being perpendicular to both the first and second directions.

17. The 3D printer according to claim 15, characterized in that, The ultrasonic detection assembly further includes at least one row of second ultrasonic probes, which are used to form a second detection sound beam propagating in the second direction, and a plurality of second ultrasonic probes belonging to the same row are arranged in the first direction.

18. The 3D printer according to claim 17, characterized in that, The ultrasonic detection assembly includes multiple rows of second ultrasonic probes arranged in a third direction, the third direction being perpendicular to the first direction and the second direction.

19. The 3D printer according to claim 17, characterized in that, The ultrasonic testing mechanism further includes a longitudinal ultrasonic detection component, which is used to form a longitudinal ultrasonic detection beam that propagates upward in a third direction within the material tray, wherein the third direction is perpendicular to the first direction and the second direction. The control mechanism is also used to obtain the three-dimensional structural information of the foreign object based on the echoes of the ultrasonic detection beam and the longitudinal ultrasonic detection beam when it is determined that there is a foreign object in the tray.

20. The 3D printer according to claim 14, characterized in that, The ultrasonic testing mechanism further includes a scanning drive component, which is connected to the ultrasonic detection component and is used to drive the ultrasonic detection component to move relative to the material tray along a preset path.

21. The 3D printer according to claim 20, characterized in that, The tray is provided with a guide rail extending along the preset path, the ultrasonic detection component slides with the guide rail, and the scanning drive component is used to drive the ultrasonic detection component to move along the guide rail.

22. The 3D printer according to claim 14, characterized in that, The ultrasonic detection component is in close contact with the side wall of the tray; the ultrasonic detection component and the tray are connected by a separate structure or an integrated structure.

23. The 3D printer according to claim 14, characterized in that, The ultrasonic detection assembly includes ultrasonic probes disposed on at least two opposite sidewalls of the tray, and the ultrasonic probes on the opposite sidewalls are arranged in a staggered manner according to the probe beam angle parameters.

24. The 3D printer according to claim 14, characterized in that, The ultrasonic testing mechanism includes an ultrasonic probe, an analog switch, an ultrasonic conversion module, and an MCU main controller; One end of the analog switch is electrically connected to the output terminal of the MCU main controller, and the other end of the analog switch is electrically connected to the ultrasonic probe. The MCU main controller is used to send a switch control signal to turn the analog switch on or off. The ultrasonic conversion module is electrically connected to the ultrasonic probe and the MCU main control. The ultrasonic conversion module is used to receive high-frequency pulse signals emitted by the MCU main control, so that the ultrasonic probe converts the high-frequency pulse signals into ultrasonic waves.

25. The 3D printer according to claim 24, characterized in that, The ultrasonic testing mechanism also includes a gain amplification module and an analog-to-digital conversion module that are electrically connected to the MCU main control unit. The analog-to-digital conversion module is used to receive the echo signal of the ultrasonic probe beam and convert the echo signal into a sampling electrical signal, and send the sampling electrical signal to the MCU main control. The gain amplification module is used to amplify the echo signal of the received ultrasonic probe beam and input it to the analog-to-digital conversion module.

26. The 3D printer according to claim 14, characterized in that, The 3D printer also includes a display screen for displaying echo images.

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