A fused deposition model 3D printing fault monitoring method and 3D printing equipment

Abstract

The present invention discloses a method for monitoring faults in fused deposition model 3D printing, which is applied to a 3D printing device. The 3D printing device at least includes a nozzle, a substrate, a wire feed module, a fault detection module, and a main control system. The fault detection module includes a control component and a camera. The method includes: obtaining model printing information; setting the movement mode of the control component and the acquisition mode of the camera; obtaining an image of the monitored area; performing fault feature calculation on the image of the monitored area to obtain a fault feature value; determining whether a printing error occurs based on the fault feature value; and issuing an error alarm if a printing error occurs. The method can quickly and in real time monitor printing faults caused by material shortages due to nozzle blockage, material breakage, etc. that may exist during the printing process of the 3D printing device, thereby reducing waste of materials and printing time.

Description

Technical Field

[0001] The present invention relates to the field of 3D printing technology, and in particular to a fused deposition model 3D printing fault monitoring method and a 3D printing device. Background Art

[0002] 3D printing equipment uses a layered manufacturing method called fused filament deposition, which heats and melts a filament of hot-melt material, extruding it through a printhead equipped with a micro-nozzle. During operation, a computer controls the movement of the printhead and 3D printing substrate along a preset path based on the model data. The printhead extrudes the filament to deposit layer by layer, ultimately completing the printout. Throughout the lengthy 3D printing process, filament breakage can occur due to material breakage, printhead blockage, and localized overheating. If undetected, filament breakage can damage the model and the 3D printing platform, wasting both material and printing time.

[0003] Therefore, there is an urgent need for a technical method to quickly detect and judge the broken wire faults that may exist in the 3D printing process. Summary of the Invention

[0004] The purpose of the present invention is to provide a fused deposition model 3D printing fault monitoring method to achieve the purpose of real-time monitoring of broken wire faults that may occur during the 3D printing process.

[0005] In order to achieve the above object, the present invention adopts the following technical means:

[0006] A fused deposition 3D printing fault monitoring method is based on a 3D printing device, wherein the 3D printing device includes a nozzle, a substrate and a fault detection module. X Direction and Z The substrate moves along Y Direction translation, the fault detection module includes Z For a camera that is translated in the Z-axis direction, the coordinate values ​​of the camera and the nozzle have the following relationship:

[0007] C z = B z + e ;

[0008] in: e is the error range, , Indicates that the nozzle is along X The minimum coordinate value that can be reached by moving in the negative direction, where C z and C xRespectively indicate that the camera is Z Direction and X The coordinate value of the direction, B z Indicates that the nozzle is Z The coordinate value of the direction;

[0009] The method comprises:

[0010] S1. Get model printing information;

[0011] S2 sets the camera's movement and acquisition mode;

[0012] S3 obtains the camera monitoring area image;

[0013] S4. Calculate the fault characteristics of the monitoring area image to obtain the fault characteristic value;

[0014] S5. Determine whether a printing error occurs based on the fault characteristic value.

[0015] Preferably, the camera moves in a manner that is aligned with the nozzle. Z The coordinate values ​​of the direction are kept synchronized, and the camera Z The range of direction coordinate values ​​is as follows:

[0016] ;

[0017] in, t i Indicates the i The printing start time of the layer, B z_start Indicates that the starting printing coordinate of the nozzle is Z The value in the direction, Indicates the interlayer spacing, i Indicates the number of layers to be printed ，e is the error range.

[0018] Furthermore, the camera acquires images of each layer.

[0019] Furthermore, the camera moves in a manner such that Z The coordinate values ​​of the direction change as follows:

[0020] ;

[0021] in, Indicates the The start printing time of each layer, Indicates the value of the starting printing coordinate of the nozzle in the Z direction, Indicates the interlayer spacing, iIndicates the number of layers to be printed. k is an integer greater than 1, e is the error range.

[0022] Preferably, the camera is collected from k’ Layer starts, every interval k Layer by layer, the camera captures images.

[0023] Preferably, the k The value range is 5~20.

[0024] Preferably, when calculating the fault characteristics of the monitoring area image, the pixel coordinate sets of the nozzle of the print head and the printed layer in each acquired image are first collected as the nozzle pixel coordinate set and the layer pixel coordinate set, respectively; the fault characteristic value is determined by processing the Euclidean distance between each pixel coordinate in the nozzle pixel coordinate set and the layer pixel coordinate set.

[0025] The present invention also provides a 3D printing device, which applies the above-mentioned fused deposition 3D printing fault monitoring method, including a nozzle, a substrate, a wire feeding module, a fault detection module and a main control system.

[0026] Preferably, the main control system can control the nozzle X Direction and Z direction of translation and the substrate in Y The fault detection module includes a control component and a camera, and the control component can control the camera to move along the direction of the fault detection module. Z The camera is a focusable camera module, and the optical axis of the camera is parallel to X axis, in Y In the direction, the coordinate value of the camera is consistent with the coordinate value of the nozzle. Z In terms of direction, the coordinate values ​​of the camera and the coordinate values ​​of the nozzle have the following relationship:

[0027] C z = B z + e ;

[0028] in: e is the error range, , Indicates that the nozzle is along X The minimum coordinate value that can be reached by moving in the negative direction. C z and B z Respectively expressed in ZThe coordinate values ​​of the camera and nozzle in the direction.

[0029] Preferably, the camera's field of view is fov Satisfies the following relationship:

[0030] ;

[0031] in, For the nozzle X The minimum coordinate position that the axis can reach when moving in the negative direction. L 1 Indicates the closest distance between the nozzle of the printhead and the layer.

[0032] The 3D printing fault monitoring method provided by the present invention can quickly and in real time monitor printing faults caused by material shortage problems such as nozzle blockage and material breakage that may occur during the printing process of a 3D printing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic diagram of the functional structure of a 3D printing device provided in this application.

[0034] Figure 2 Schematic diagram of a fused deposition model 3D printing fault monitoring method provided in this application.

[0035] Figure 3 This is a schematic diagram of the first relationship between the camera position and the nozzle position under the first viewing angle provided in this application.

[0036] Figure 4 This is a schematic diagram of the second relationship between the camera position and the nozzle position under the first viewing angle provided in this application.

[0037] Figure 5 This is a schematic diagram of the relationship between the camera position and the nozzle position under the second viewing angle provided in this application.

[0038] Among them, 10-nozzle, 20-substrate, 30-fault detection module, 301-camera, 302-control component. DETAILED DESCRIPTION

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0040] refer to Figure 1 , Figure 1The figure is a functional structure diagram of a 3D printing device. The 3D printing device includes at least a nozzle 10, a substrate 20, a fault detection module 30, a wire feeding module (not shown in the figure), and a main control system (not shown in the figure). The fault detection module 30 includes a control component 302 and a camera 301. The control component 302 can control the camera 301 to move along the Z The fault detection module 30 and the main control system can communicate with each other. The main control system can control the nozzle 10 to move in the direction of X Direction and Z direction of translation and the substrate 20 in Y Directional translation, and control the fault detection module 30 to perform fault monitoring.

[0041] When the 3D printing device performs the printing task of the model, it obtains the path of each layer according to the slice file of the three-dimensional model and determines the position of the nozzle 10 in the printing process. X and Z The moving path in the direction and the inter-layer spacing between the layers, under the control of the main control system, the substrate 20 moves along Y direction and the nozzle 10 moves according to its XZ The moving path on the plane moves and the filament is extruded from the nozzle on the nozzle 10, and the hot melt material is bonded to the substrate or the previous layer that has been solidified. After each layer of printing is completed, the nozzle 10 is controlled to move along the Z The nozzle 10 moves in the direction of the layer spacing, and the printing is repeated layer by layer, and the final model is formed after the material accumulation of all layers is completed. X Direction and Z The position in direction changes in real time.

[0042] The fault detection module 30 is arranged on one side of the substrate 20, and the control component 302 is specifically an electric displacement stage for adjusting the control camera 301 along the Z The camera 301 is a camera module. The optical axis of the camera 301 is approximately parallel to X Axis, when the fault detection module 30 is fixedly assembled, the camera 301 is X Direction and Y The coordinate value of the direction is fixed. Z The coordinate value of the direction changes with the control of the control component 302. The position coordinate of the nozzle 10 is represented by the center coordinate of the nozzle on the nozzle 10. Y The coordinate value of the direction is a fixed value, and the camera 301 is in Y The coordinate values ​​in the direction and the nozzle 10 in Y The direction coordinate values ​​remain the same. Camera 301 Z The coordinate values ​​in the direction and the nozzle ZThe coordinate values ​​in the direction satisfy the following relationship:

[0043] ;

[0044] in, ;

[0045] In the above formula, C z Indicates that camera 301 is Z Coordinate values ​​in the direction; B z Indicates that the nozzle is Z Coordinate value in the direction.

[0046] when e =0, C z = B z .when e When it is not equal to 0, e The value is similar to an error range, which makes the nozzle B z Although the value of C z Different, but still within 1 degree of the camera's center field of view The calculation is done within a range of 1 degree. Here, 1 degree can also be 1 to 5 degrees. As long as the camera module has a good camera effect, 5 degrees is also acceptable. Can also be replaced by to Any number, including .

[0047] Furthermore, in the above formula, Indicates that the nozzle is along X The minimum coordinate value that can be reached by moving in the negative direction.

[0048] above C z The value is set so that the nozzle 10 and the top several layers close to the nozzle 10 are within the central field of view of the camera 301. The portion of interest in the image captured by the camera 301 is always in the center, which is beneficial to obtaining a high-definition image. The imaging quality of the central field of view of the camera 301 is better than that of the edge field of view. On the other hand, in the case where there is a need to capture the image of the portion of interest in the original image captured by the camera 301, it is beneficial to improve the efficiency of image capture.

[0049] like Figure 2 FIG. 1 is a schematic diagram of a 3D printing fault monitoring method provided by the present invention. The method comprises the following steps:

[0050] Step S1: Obtain model printing information;

[0051] Specifically, when the 3D printing device starts the printing task of the 3D model, the main control system obtains the model printing information according to the slice file of the 3D model. The model printing information includes the starting printing coordinates of the nozzle 10. Z Value in direction , interlayer spacing and the printing start time of each layer ,in i Indicates the number of layers to be printed. i = 1 … K , K is the total number of layers.

[0052] Step S2: Setting the movement mode of the control component and the acquisition mode of the camera;

[0053] The camera acquisition method can be to set the camera to collect images of each layer. Specifically, the camera collects images according to the time period during the printing process of each layer. T Capture images. Time period T It means starting from the printing start time of each layer, T The time camera collects an image.

[0054] The camera can also be set to collect data from the first k’ Layer starts, every interval k Layer by layer, the camera collects images. k’ Can be equal to k It can also be different. Specifically, when k’ Start printing from the first layer. k’ Layer, camera according to the time cycle T To collect images; k’ + k +1 layer, camera follows time cycle T To collect images; k’ +2 k +1 layer, camera follows time cycle T To collect images; .... Since the camera does not need to collect images during each layer printing process, it can be used to collect images during each printing process. k After each layer is sliced, the camera collects images, which can reduce the power consumption of the camera. At the same time, if the nozzle does not spit out silk, it is difficult to identify the 0.1mm fault features from the collected image because the layer spacing is very small, usually 0.1mm. k As the printing time of each layer increases, the fault distance will increase. ktimes, making it easy to identify fault features on the acquired image and improving the accuracy. k The value of is an integer greater than 1. k Taking a value between 5 and 20 is beneficial to the calculation of fault characteristics in the subsequent steps, and when a printing error fault is detected, the waste of materials can be ignored.

[0055] The movement mode of the control component 302 refers to the control component 302 controlling the camera 301 to move along Z The motion trajectory of the camera 301 in the direction Z How the coordinates of a direction change over time.

[0056] When the acquisition mode of the camera 301 is to set the camera to acquire images of each layer, the movement mode of the control component 302 is set to Y The coordinate values ​​of the control camera 301 and the coordinate values ​​of the nozzle 10 are kept synchronized. Figure 3 and Figure 4 As shown, when printing the first layer, the control component 302 controls the camera 301 to Z Direction of movement C z_start = B z_start + e The location, where and They can be equal, or they can differ by taking into account errors or limitations. e ;like Figure 3 middle PC 1 Position shown, first layer PB 1 During the printing process, the camera 301 collects images; when the first layer of printing is completed, the control component 302 controls the camera 301 to move along Z Move one layer spacing distance in the positive direction , that is, move to The position of Figure 4 middle PC 2 The position shown in FIG. 1 is controlled by the camera 301 to focus on the second layer of the sheet. PB 2 The image is collected during the printing process; and so on. i When the layer printing is completed, the control component 302 controls the camera 301 to move to The position of the camera 301 is controlled i The camera 301 collects images during the printing process of each layer. Z Direction coordinate value C zThe range of changes is as follows:

[0057] ;

[0058] Indicates time C z The value of , .

[0059] When the camera acquisition mode is set to k’ Layer starts, every interval k When the camera collects images layer by layer, the control component 302 controls the camera 301 to Z Direction coordinates C z The range of changes is as follows:

[0060] ;

[0061] The above relationship is expressed in At this moment, control the camera 301 to Z Move to C z , C z The value of , , For the i + k The start printing time of each layer.

[0062] The above formula describes the correspondence between time and position, which controls the camera t time, Z The coordinates are moved to the position indicated later.

[0063] i It is not a collection point, but is used to represent a variable integer. Mathematically, it represents a series of values. i Taking 1, 2, 3, 4, ... respectively, we can get the corresponding relationship, that is, t 1 Control the camera at all times B z_start + e location, t 2 Control the camera to According to this corresponding relationship, the 3D printing device controls the movement trajectory of the camera.

[0064] Step S3: Acquire an image of the monitored area;

[0065] During the printing process of each layer, the camera 301 T , among which, here T Indicates the acquisition time interval set for obtaining multiple acquired images during the layer-by-layer printing process; the image acquisition time period T It is a preset value and can be set according to actual needs, for example, the time period T If the time interval is 2s, the camera 301 collects images every 2s.

[0066] like Figure 3 、 Figure 4 or Figure 5 As shown, the monitored area includes the nozzle of the printhead 10 and several printed layers near the bottom of the nozzle.

[0067] Since the shooting optical axis of the camera 301 is parallel to X direction, the camera 301 is in Z The coordinates of the direction and the nozzle 10 along Z The coordinates of the direction are kept consistent, and combined with the setting of the movement mode of the control component 302 in step S2, the monitored area is always covered by the central field of view of the camera 301. At the same time, considering that only a small central part of the original image collected by the camera with a large shooting field of view contains the monitored area, on the one hand, each frame of the original image collected needs to be cropped, which increases the processing flow and time, and on the other hand, it also wastes the resolution of the camera. Figure 5 As shown, by designing the shooting field of view of camera 301 fov Satisfies the following relationship:

[0068] ;

[0069] in, For nozzle 10 X The minimum coordinate position that the axis can reach when moving in the negative direction. L 1 Indicates the shortest distance between the nozzle of the nozzle 10 and the layer. If the camera acquisition method can be set to capture images of each layer and the nozzle does not spit out silk, L 1 The value is approximately one interlayer distance , interlayer spacing Generally, it is 0.1~0.3mm; if the camera acquisition method is to set the camera from the k’ Layer starts, every interval k When the camera is collecting images layer by layer and the nozzle fails to spit out silk (broken silk) L 1 The maximum value of kThe distance between layers .

[0070] In the optical imaging design of the camera, the above fov The design of a relational camera is not only less difficult and easy to obtain high spatial resolution image quality, but also has a large coverage rate of the monitored area in the original image, and no subsequent cropping is required.

[0071] Step S4: Calculate the fault characteristics of the monitored area image to obtain the fault characteristic value;

[0072] The original image captured by camera 301 is first subjected to conventional image processing operations, such as grayscale processing, denoising, and filtering, to obtain a first image. A feature recognition algorithm is then used to obtain the pixel coordinates of the nozzle image and the pixel coordinates of the printed layer image in the first image. The nozzle pixel coordinates in the first image refer to the coordinates of all pixels in the first image that constitute the nozzle image, denoted as the nozzle pixel coordinates set, which also includes the pixels of the filament within the nozzle. The printed layer pixel coordinates in the first image refer to the coordinates of all pixels in the first image that constitute the printed layer image, denoted as the layer pixel coordinates set. The closest pixel pair in the nozzle pixel coordinates set and the layer pixel coordinates set is calculated. Specifically, the Euclidean distance between the coordinates of a pixel in the nozzle pixel coordinates set and each pixel in the layer pixel coordinates set can be calculated to obtain a series of Euclidean distances. The Euclidean distance between each pixel in the nozzle pixel coordinates set and each pixel in the layer pixel coordinates set is then calculated across all pixels in the nozzle pixel coordinates set. The minimum of these Euclidean distances is then used as the fault signature.

[0073] Step S5 determines whether a printing error occurs based on the fault characteristic value. If it is determined that a printing error occurs, the process proceeds to step S6. If it is determined that no printing error occurs, the process returns to step S3.

[0074] The threshold value of the fault characteristic value of printing failure is pre-set and can be set according to actual needs. For example, the threshold value can be determined based on the distance between the nozzle pixel and the layer pixel during normal printing. For another example, when each layer collects the image of the monitored area, the threshold value can be equal to or less than , is the interlayer distance mentioned above, that is, the layer thickness. The fault characteristic value obtained in step S4 is compared with the threshold. If it exceeds the threshold, it indicates that the printhead is broken or not spinning, and a printing error is determined to have occurred, and the process proceeds to step S6. If the fault characteristic value is within the threshold, it indicates that the printhead is not broken or is spinning normally, and no printing error is determined to have occurred, and the process returns to step S3.

[0075] Step S6: issuing a printing error alarm and stopping the printing task;

[0076] Specifically, if a printing error is confirmed to have occurred, a printing error alarm is issued. The printing error alarm can be displayed on the control panel in the form of text or can be used as a warning in the form of sound.

[0077] The 3D printing fault monitoring method provided by the present invention can quickly and in real time monitor printing faults caused by material shortage problems such as nozzle blockage and material breakage that may occur during the printing process of a 3D printing device.

[0078] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring faults in fused deposition 3D printing, characterized in that: Based on 3D printing equipment, the 3D printing equipment includes a nozzle, a substrate and a fault detection module. X Direction and Z The substrate moves along Y Direction translation, the fault detection module includes Z The camera is panned in the direction Z In the axis direction, the coordinate values ​​of the camera and the nozzle have the following relationship: C z = B z + e ； in: e is the error range, , B x_min Indicates that the nozzle is along X The minimum coordinate value that can be reached by moving in the negative direction, where C z and C x Respectively indicate that the camera is Z Direction and X The coordinate value of the direction, B z Indicates that the nozzle is Z The coordinate value of the direction; The method comprises: S1. Get model printing information; S2 sets the camera's movement and acquisition mode; S3 obtains the camera monitoring area image; S4. Calculate the fault characteristics of the monitoring area image to obtain the fault characteristic value; S5. Determine whether a printing error occurs based on the fault characteristic value; Among them, when calculating the fault characteristics of the monitoring area image, the pixel coordinate sets of the nozzle of the printhead and the printed layer in each acquired image are first collected as the nozzle pixel coordinate set and the layer pixel coordinate set, respectively; the fault characteristic value is determined by processing the Euclidean distance between each pixel coordinate in the nozzle pixel coordinate set and the layer pixel coordinate set.

2. A fused deposition model 3D printing fault monitoring method according to claim 1, characterized in that: The movement of the camera is in the same manner as the nozzle Z The coordinate values ​​of the direction are kept synchronized, and the camera Z When printing starts on the i-th layer, the coordinate value of the direction is: ； in, B z_start Indicates that the starting printing coordinate of the nozzle is Z The value in the direction, Indicates the interlayer spacing, i Indicates the number of layers to be printed. e is the error range.

3. A fused deposition model 3D printing fault monitoring method according to claim 1 or 2, characterized in that: The camera acquires images of each layer.

4. A fused deposition model 3D printing fault monitoring method according to claim 1, characterized in that: The camera moves in a manner such that Z The coordinate values ​​of the direction change as follows: In the i + k When printing starts layer by layer, the coordinate values ​​are: ； in, B z_start Indicates that the starting printing coordinate of the nozzle is Z The value in the direction, Indicates the interlayer spacing, i Indicates the number of layers to be printed. k is an integer greater than 1, e is the error range.

5. A fused deposition model 3D printing fault monitoring method according to claim 1 or 4, characterized in that: The camera is collected in the following way: k’ Layer starts, every interval k Layer by layer, the camera captures images.

6. A fused deposition model 3D printing fault monitoring method according to claim 5, characterized in that: described k The value range is 5~20.

7. A 3D printing device, characterized in that: A fused deposition model 3D printing fault monitoring method according to any one of claims 1 to 6 comprises a nozzle, a substrate, a wire feeding module, a fault detection module and a main control system.

8. The 3D printing device according to claim 7, characterized in that: The main control system controls the nozzle X Direction and Z direction of translation and the substrate in Y The fault detection module includes a control component and a camera, and the control component can control the camera to move along the direction of the fault detection module. Z The camera is a focusable camera module, and the optical axis of the camera is parallel to X axis, in Y In the direction, the coordinate value of the camera is consistent with the coordinate value of the nozzle. Z In terms of direction, the coordinate values ​​of the camera and the coordinate values ​​of the nozzle have the following relationship: C z = B z + e ； in: e is the error range, , B x_min Indicates that the nozzle is along X The minimum coordinate value that can be reached by moving in the negative direction. C z and B z Respectively expressed in Z The coordinate values ​​of the camera and nozzle in the direction.

9. The 3D printing device according to claim 8, characterized in that: The camera's field of view fov The following relationship is satisfied: ； in, B x_min For the nozzle X The minimum coordinate position that the axis can reach when moving in the negative direction. L 1 Indicates the closest distance between the nozzle of the printhead and the layer.

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