CN117584448A

CN117584448A - Integrated printing nozzle device and printing method for 3D printing process monitoring

Info

Publication number: CN117584448A
Application number: CN202311574159.XA
Authority: CN
Inventors: 王叶松; 戴正兵; 孙梓轩; 张礼华; 李飞龙
Original assignee: Jiangsu University of Science and Technology
Current assignee: Jiangsu University of Science and Technology
Priority date: 2023-11-23
Filing date: 2023-11-23
Publication date: 2024-02-23

Abstract

The invention discloses an integrated printing nozzle device and a printing method for monitoring a 3D printing process, wherein a camera and a printing nozzle are integrated together, a steering engine I is started to adjust the relative position between the printing nozzle and the camera, and a steering engine II is started to rotate to the shooting angle of the steering engine II as the nozzle direction of the printing nozzle; shooting the state and the characteristics of the printing wire in the printing process by a camera, carrying out noise reduction treatment on the shot image, and uploading the shot image to a computer to obtain the actual width of the printing wire; comparing the actual width with the expected range of the printing wire width, and adjusting parameters in the printing process when the actual width exceeds the expected range, so as to ensure that the actual width is restored to be within the range of the expected value range; the relative movement of the printing spray head and the camera is realized through the displacement of the sliding block, so that the relative position between the camera and the printing spray head can be controlled, the relative angle between the camera and the printing spray head can be controlled, the shooting angle of the camera is controlled so as to be convenient for better picture collection, the operation is easy, the control precision is high, and the printing efficiency and the printing accuracy are improved.

Description

Integrated printing nozzle device and printing method for 3D printing process monitoring

Technical Field

The invention belongs to the field of 3D printing technology and process monitoring, and particularly relates to an integrated printing spray head device and a printing method for printing process monitoring.

Background

The 3D molding technology comprises the following steps: metal powders are laser sintered directly, selectively, three-dimensionally printed bond molded, and Fused Deposition Molded (FDM), with Fused Deposition Molded (FDM) being a broader application. In the printing process, the printing process is monitored to ensure the printing quality thereof so as to find and solve the problems in time. .

Chinese patent publication No. CN115288445A, name are building 3D print shower nozzle device with variable radian, including shower nozzle main part, mount, bearing, quick-operation joint and rotation axis etc. there are four inner chambers at the shower nozzle middle part, through controlling the atmospheric pressure value of four cavitys and then control extrusion volume respectively, realize the evenly distributed of variable radian route extrusion material, solve the radian route and print the inhomogeneous problem of in-process ejection of compact. Chinese patent publication No. CN202121747469.3, name are 3D print shower nozzle device, including feeding mechanism and shower nozzle mechanism through setting up first driving piece drive shower nozzle and shrink, make between the spouting material mouth of shower nozzle and the part form one section cellosilk, then second driving piece drive shearing sword carries out normal position shearing to the cellosilk of spouting material mouth department of shower nozzle, makes part breakpoint department can not remain one section cellosilk, guarantees the quality of part and guarantees the precision of secondary printing after jumping the point. The Chinese patent publication No. CN112891016A, named a controllable temperature low-temperature biological 3D printing spray head device, can adjust the temperature of biological materials according to the needs, is beneficial to ensuring the consistency of the performance of the biological materials, can be combined with an original low-temperature cooling platform to break through the layer height of the low-temperature biological 3D printing, and allows more materials to be applied to the low-temperature biological 3D printing technology. Chinese patent publication No. CN209682924U, name is an optional single colour mixing double-out 3D printing nozzle device, and a nozzle can realize the switching among monochromatic, colour mixing and colour matching printing, reduces 3D printing cost.

Therefore, the improvement of the existing 3D printing spray head device is to add new components on the basis of the printing spray head body to complete new functions, such as the functions of variable radian path printing, secondary printing after break points and jump points, temperature adjustment printing, color mixing printing and the like, and complex algorithms are required while the new functions are realized. However, these printing head devices have common problems that: in the motion process of the printing spray head, the position and state information of the printing spray head cannot be known, the function of monitoring the printing spray head cannot be realized, and when 3D printing is wrong or the rejection rate is generated, the printing spray head cannot be found in time.

Disclosure of Invention

Aiming at the problems existing in the existing 3D printing technology, the invention provides a brand-new integrated printing nozzle device which can be used for monitoring the printing process, and the printing process is monitored by installing the integrated printing nozzle device on a printer.

The invention discloses an integrated printing nozzle device for monitoring a 3D printing process, which adopts the following technical scheme: the printing spray head is provided with a camera beside the printing spray head, the printing spray head is connected to the bottom plate in a sliding way through a printing spray head mounting plate, the camera is fixedly connected with a camera mounting frame, the camera mounting frame is placed on the camera mounting plate, and the camera mounting plate is connected to the bottom plate in a sliding way; two mutually parallel sliding guide rails, namely a first linear guide rail and a second linear guide rail, are arranged on the upper surface of the bottom plate, the lower surface of the printing nozzle mounting plate is fixedly connected with a first sliding block matched with the first linear guide rail, and the lower surface of the camera mounting plate is fixedly connected with a second sliding block matched with the second linear guide rail; the printing nozzle mounting plate is fixedly connected with a first rack on the side facing the camera, the camera mounting plate is fixedly connected with a second rack on the side facing the printing nozzle mounting plate, a gear which is meshed with the first rack and the second rack simultaneously is arranged between the first rack and the second rack, and the central shaft of the gear is fixedly connected with the output end of the steering engine I; and a steering engine II is arranged below the camera mounting plate, an output shaft of the steering engine II is fixedly connected with a steering wheel, and the steering wheel is fixedly connected with the camera mounting frame.

The printing method of the integrated printing nozzle device adopts the following technical scheme: starting a steering engine I to adjust the relative position between the printing spray head and the camera, and starting a steering engine II to rotate the camera until the shooting angle of the steering engine II is the direction of the nozzle of the printing spray head;

shooting the state and the characteristics of the printing wire in the printing process by a camera, carrying out noise reduction treatment on the shot image, and uploading the shot image to a computer to obtain the actual width of the printing wire;

and comparing the actual width with the expected range of the printing wire width, and adjusting parameters in the printing process when the actual width exceeds the expected range, so as to ensure that the actual width is restored to be within the range of the expected value range.

Further, after printing, the surface of a printing part is scanned, the relative position of a steering engine I for adjusting the camera and a printing spray head is started, the nozzle of the printing spray head is adjusted to be flush with a printing spray head mounting plate, the camera is adjusted to be parallel to the printing spray head, the camera scans the surface of the printing part through the XY axis movement of the 3D printer, the scanned image is uploaded to a computer, and the computer evaluates the surface quality of the printing part.

Further, the method for evaluating the surface quality of the printed piece comprises the steps of preprocessing an image, extracting characteristics, and detecting defects through a convolutional neural network model.

Further, the deviation between the size and shape of the printed matter and the design specification is calculated, and the surface quality score of the printed matter is obtained through the weighted index calculation.

Further, the quality scores g=ω1×g1+ω2×g2, ω1 and ω2 are calculated as weights of the feature and defect, respectively, the quality scores are compared with the quality scores conforming to the standard, and the quality of the print is determined based on the result of the comparison

The invention has the advantages that:

1. the device is simple, easy to operate and high in control precision, 3D printing errors and rejection rate can be reduced to a large extent, printing efficiency and accuracy are improved, and practical and economic benefits are achieved.

2. The printing method is simple, after preprocessing the 3D model, the data after slicing the model is led to the 3D printer, then the device is installed on the printer, and in the printing process, the device can adjust the relative position and angle of the camera and the printing nozzle, and the shot picture data is transmitted to the computer for analysis and processing.

3. The invention realizes the relative movement of the printing nozzle and the camera through the displacement of the sliding block, not only can control the relative position between the camera and the printing nozzle, but also can control the relative angle between the camera and the printing nozzle, and can control the shooting angle of the camera so as to be convenient for better collecting pictures.

4. Because the camera and the printing nozzle have a certain angle, the shot picture is processed by the corresponding graphic processing technology and then is transmitted with data, the surface of the printing piece is scanned after printing, the camera scans the surface of the printing piece by the XY axis movement of the 3D printer, the scanned image is uploaded to the computer after being processed by the image technology, and the computer evaluates the surface quality of the printing piece by the machine vision, so that the surface quality of the printing piece is ensured.

Drawings

The invention is described in further detail below with reference to the attached drawings and detailed description:

FIG. 1 is a block diagram of an integrated print head device for 3D printing process monitoring in accordance with the present invention;

FIG. 2 is a schematic top view of FIG. 1 with the camera, print head, and steering engine II removed;

FIG. 3 is a schematic perspective view of the structure of FIG. 1 with the camera, print head and steering engine II removed;

fig. 4 is a schematic structural diagram of the steering engine two and the connecting parts thereof in fig. 1;

FIG. 5 is a schematic view of the structure of the base plate and its upper rail in FIG. 2;

FIG. 6 is a flow chart of a printing method of the integrated print head device of the present invention;

in the figure: 1. the printing device comprises a camera, a printing nozzle, a base plate, a linear guide rail I, a printing nozzle mounting plate, a rack I, a gear 7, a camera mounting plate 8, a linear guide rail II, a slider I, a steering engine 12, a rack II, a slider II, a camera mounting frame 14, a steering wheel 15, a steering wheel 16, a steering engine II and a base plate long groove.

Detailed Description

Referring to fig. 1, 2 and 3, an integrated printing head apparatus for 3D printing process monitoring of the present invention includes a printing head 2, and a camera 1 is disposed beside the printing head 2. The printing nozzle 2 is connected onto the bottom plate 3 in a sliding way through the printing nozzle mounting plate 5, the camera 1 is fixedly connected with the camera mounting frame 14, the camera mounting frame 14 is placed on the camera mounting plate 8, and the camera mounting plate 8 is connected onto the bottom plate 3 in a sliding way.

Two sliding guide rails are arranged on the upper surface of the bottom plate 3, namely a first linear guide rail 4 and a second linear guide rail 9, and the first linear guide rail 4 and the second linear guide rail 9 are parallel to each other. The lower surface of the printing nozzle mounting plate 5 is fixedly connected with a first sliding block 10, and the first sliding block 10 is matched with the first linear guide rail 4 and can slide back and forth along the first linear guide rail 4. The lower surface of the camera mounting plate 8 is fixedly connected with a second slider 13, and the second slider 13 is matched with the second linear guide rail 9 and can slide back and forth along the second linear guide rail 9. The printing head 2 and the printing head 2 are moved back and forth by the movement of the first slider 10 and the second slider 13.

The installation positioning grooves for respectively assembling the first linear guide rail 4 and the second linear guide rail 9 are formed in the bottom plate 3, so that the accuracy of the first linear guide rail 4 and the second linear guide rail 9 can be guaranteed while the first linear guide rail 4 and the second linear guide rail 9 are installed, and later control is more accurate. The print head mounting plate 5 is aligned and positioned with the screw hole on the first slider 10 through the upper screw hole and is connected through a screw, the screw holes on the print head mounting plate 5 are counter sunk holes so as to avoid unnecessary interference from influencing, the camera mounting plate 8 is aligned with the screw hole on the second slider 13 through the upper screw hole to achieve the positioning effect, and the counter sunk holes are also adopted on the camera mounting plate 8 so as to avoid unnecessary interference from influencing.

The print head mounting plate 5 is fixedly connected to a first rack 6 on the side facing the camera 1, and the camera mounting plate 8 is fixedly connected to a second rack 12 on the side facing the print head mounting plate 5. The first rack 6 and the second rack 12 are parallel to each other and have the same height, and are parallel to the first linear guide rail 4 and the second linear guide rail 9. A gear 7 is arranged between the first rack 6 and the second rack 12, the central axis of the gear 7 is perpendicular to the first rack 6 and the second rack 12, the height of the gear 7 is consistent with that of the first rack 6 and the second rack 12, and the first rack 6 and the second rack 12 are arranged on two sides of the gear 7 and meshed with the gear 7 at the same time.

The central shaft of the gear 7 is fixedly connected with the output end of the steering engine I11, the shell of the steering engine I11 is connected to the bottom plate 3 through a hexagonal socket head stud, and a countersunk hole is formed in the bottom plate 3 to prevent interference caused by screw connection from affecting the normal operation of the device. The steering engine I11 works to drive the gear 7 to rotate, and the printing spray head 2 are driven to move through the rack I6 and the rack II 12, so that the relative distance between the camera 1 and the printing spray head 2 can be adjusted.

When the steering engine I11 is started, the steering engine I11 transmits power to the gear 7, and as the gear 7 is meshed with the rack I6 and the rack II 12 at the same time, the power is transmitted to the printing head mounting plate 5 and the camera mounting plate 8 in opposite directions, and the printing head mounting plate 5 and the camera mounting plate 8 transmit power to the first slide block 10 and the second slide block 13 which are connected with the printing head mounting plate 5 and the camera mounting plate respectively, so that the printing head mounting plate slides in opposite directions on the first linear guide rail 4 and the second linear guide rail 9, and the function of controlling the relative distance between the camera 1 and the printing nozzle 2 is realized.

Referring to fig. 4, a second steering engine 16 is arranged below the camera mounting plate 8, the second steering engine 16 is connected to the camera mounting plate 8 through four hexagonal socket studs, and the positioning mode is that positioning screw holes are formed in the camera mounting plate 8 in advance, and the holes are countersunk so as to avoid interference. Steering wheel 15 is arranged above steering wheel II 16, steering wheel 15 is fixedly connected to the output shaft of steering wheel II 16, the central shaft of steering wheel II 16 and steering wheel 15 is parallel to the output shaft of steering wheel I11, and is perpendicular to rack I6 and rack II 12. The steering wheel 15 is fixedly connected with the camera mounting frame 14. The camera mounting plate 8 is provided with a hole with a diameter slightly larger than that of the steering wheel 15, so that the steering engine II 16 is conveniently mounted so as not to interfere, and the camera mounting plate 14 is connected with the steering wheel 15 by screws through the mounting grooves on the camera mounting plate 14 and the four countersunk screw holes. When the steering engine II 16 is started, the steering engine II 16 transmits power to the steering wheel 15, the steering wheel 15 transmits power to the camera mounting frame 14 to drive the camera 1 to rotate, and the angle between the camera 1 and the printing spray head 2 is changed.

Referring to fig. 5, when the camera 1 moves back and forth under the driving of the gear 7 and the rack two 12, the steering engine two 16 moves back and forth along with the camera mounting plate 8 and the camera 1, in order to prevent interference between the steering engine two 16 and the bottom plate 3, a bottom plate long groove 17 is formed in the bottom plate 3, enough sliding space is reserved, and the steering engine two 16 moves back and forth in the bottom plate long groove 17 without collision with the bottom plate 3.

When the integrated printing nozzle device shown in fig. 1-5 is used, as shown in fig. 6, the integrated printing nozzle device is firstly installed on a 3D printer, a 3D model is established through CAD software before printing starts, files are stored into STL format, the stored STL format files are imported into slicing software, proper printing parameters are set, the printing parameters comprise printing temperature, printing layer height and the like, corresponding G codes are generated after slicing is completed, and the 3D printer is controlled to work through an upper computer.

When the 3D printer works, in order to realize real-time monitoring of the printing process, the camera 1 and the printing nozzle 2 need to be adjusted to a proper position before printing starts: firstly, the steering engine I11 is started to adjust the relative position between the printing spray head 2 and the camera 1, the camera 1 is rotated by about 18 degrees through the rotation of the steering engine II 16, and at the moment, the shooting angle of the camera 1 is just the nozzle direction of the printing spray head 2, so that the printing process can be monitored in real time. The real-time monitoring steps are as follows:

step 1: and (5) image acquisition. The camera 1 is used to take images during printing which capture the status and characteristics of the printing filaments during actual printing.

Step 2: and (5) image processing. The camera 1 uploads the acquired image to the computer, and the acquired image needs to be processed before uploading, which may cause noise in the image due to various complex factors such as ambient light, camera noise, etc., in order to ensure accurate feature recognition, noise reduction processing needs to be performed on the image, and mean filtering is a noise reduction method used for reducing noise in the image.

Step 3: and (5) feature identification. The noise reduced image is fed into a feature recognition system in the computer for analyzing the width of the printing wire, including detecting the contour or other relevant features of the printing wire, and after feature recognition, obtaining the actual width of the printing wire, which is labeled a.

Step 4: expected value comparison. The expected value range b of the width of the printing wire is prestored in the computer, the actual width a is compared with the expected range b, and an alarm is issued once the expected range b is exceeded, because this indicates that the width of the printing wire deviates from the expected range.

Step 5: adjusting parameters during printing, such as nozzle temperature, nozzle speed, printing speed, etc., ensures that the actual width a of the print wire is restored to within the range of expected value range b.

After printing, scanning the surface of a printed piece, and detecting defects: firstly, a steering engine I11 is started to adjust the relative positions of a camera 1 and a printing spray head 2, the nozzle of the printing spray head 2 is adjusted to be flush with a printing spray head mounting plate 5, the camera 1 is adjusted to be parallel to the printing spray head 2 through the rotation of a steering engine II 16, the camera 1 scans the surface of a printer through the self-carried XY axis movement of a 3D printer, scanned images are uploaded to a computer after being processed by an image technology, and the computer evaluates the surface quality of a printed piece through machine vision. The procedure for evaluating the surface quality of the prints was as follows:

step 1: and (5) preprocessing an image. Image preprocessing involves removing noise using gaussian filtering and correcting the image with geometric matrix transformation, helping to improve the accuracy of subsequent analysis.

Step 2: and (5) extracting characteristics. The machine vision system extracts key features of the surface of the printed product through an edge detection algorithm (Canny), wherein the feature extraction is used for helping to understand the content of the image, the features comprise textures, shapes, edges and the like, and the feature marks are analyzed to obtain a feature score g1.

Step 3: and (5) defect detection. Defects, which may include cracks, pits, spots, etc., are detected by Convolutional Neural Network (CNN) models, the images are analyzed and potential problems are marked, represented by a defect score g 2.

Step 4: data analysis and comparison: and comparing the print data with a predefined quality standard, and calculating deviation between the size and shape of the print and the design specification to judge whether the print is consistent with the design specification, wherein the deviation e= |actual size d 1-design size d2|.

Step 5: quality scoring. The surface quality score of the printed piece is obtained through weighted index calculation and is used for evaluating whether the printed piece meets quality standards, and the quality score G=ω1 is characteristic score g1+ω2 is defect score G2, wherein ω1 and ω2 are weights of corresponding characteristics and defects. The quality score meeting the standard is G1, the quality score G is compared with the quality score G1 meeting the standard, the quality of the printing part is judged according to the comparison result, when the difference greatly exceeds a set range, the quality of the printing part is judged to be poor, and otherwise, the printing part is judged to be qualified.

Step 6: report generation. The report generated contains the evaluation information of the quality of the surface of the printed matter, the detected problems and parameter suggestions to be improved during the next printing process, and finally the printing is stopped.

Claims

1. An integrated printing head device for 3D printing process monitoring, having a printing head (2), characterized by: a camera (1) is arranged beside a printing spray head (2), the printing spray head (2) is connected to the bottom plate (3) in a sliding way through a printing spray head mounting plate (5), the camera (1) is fixedly connected with a camera mounting frame (14), the camera mounting frame (14) is arranged on a camera mounting plate (8), and the camera mounting plate (8) is connected with the bottom plate (3) in a sliding way; two mutually parallel sliding guide rails are arranged on the upper surface of the bottom plate (3), namely a first linear guide rail (4) and a second linear guide rail (9), the lower surface of the printing nozzle mounting plate (5) is fixedly connected with a first sliding block (10) matched with the first linear guide rail (4), and the lower surface of the camera mounting plate (8) is fixedly connected with a second sliding block (13) matched with the second linear guide rail (9); the printing nozzle mounting plate (5) is fixedly connected with the first rack (6) at the side facing the camera (1), the camera mounting plate (8) is fixedly connected with the second rack (12) at the side facing the printing nozzle mounting plate (5), a gear (7) which is meshed with the first rack (6) and the second rack (12) simultaneously is arranged between the first rack (6) and the second rack (12), and the central shaft of the gear (7) is fixedly connected with the output end of the steering engine (11); and a steering engine II (16) is arranged below the camera mounting plate (8), an output shaft of the steering engine II (16) is fixedly connected with a steering wheel (15), and the steering wheel (15) is fixedly connected with the camera mounting frame (14).

2. An integrated print head assembly for 3D printing process monitoring as claimed in claim 1, wherein: the bottom plate (3) is provided with a bottom plate long groove (17), and the steering engine II (16) moves back and forth in the bottom plate long groove (17) without collision with the bottom plate (3).

3. An integrated print head assembly for 3D printing process monitoring as claimed in claim 1, wherein: the bottom plate (3) is provided with positioning grooves for respectively assembling the first linear guide rail (4) and the second linear guide rail (9).

4. An integrated print head assembly for 3D printing process monitoring as claimed in claim 1, wherein: the first rack (6) and the second rack (12) are parallel to each other and have the same height, and are parallel to the first linear guide rail (4) and the second linear guide rail (9).

5. An integrated print head assembly for 3D printing process monitoring as claimed in claim 1, wherein: the output shaft of the steering engine II (16) and the central shaft of the steering wheel (15) are parallel to the output shaft of the steering engine I (11).

6. A method of printing an integrated print head assembly as claimed in claim 1, wherein:

the steering engine I (11) is started to adjust the relative position between the printing spray head (2) and the camera (1), and the steering engine II (16) is started to rotate the camera (1) until the shooting angle is the nozzle direction of the printing spray head (2);

the method comprises the steps that a camera (1) shoots the state and the characteristics of printing wires in the printing process, and the shot image is uploaded to a computer after noise reduction treatment to obtain the actual width of the printing wires;

7. The printing method according to claim 6, characterized in that: after printing, scanning the surface of a printing part, starting a steering engine I (11) to adjust the relative positions of a camera (1) and a printing spray head (2), adjusting the nozzle of the printing spray head (2) to be parallel to a printing spray head mounting plate (5), adjusting the camera (1) to be parallel to the printing spray head (2), scanning the surface of the printing part by the camera (1) through the XY axis movement of a 3D printer, uploading the scanned image to a computer, and evaluating the surface quality of the printing part by the computer.

8. The printing method according to claim 7, characterized in that: the method for evaluating the surface quality of the printed piece comprises the steps of preprocessing an image, extracting characteristics, and detecting defects through a convolutional neural network model.

9. The printing method according to claim 8, characterized in that: and calculating the deviation between the size and shape of the printed piece and the design specification, and calculating through a weighted index to obtain the surface quality score of the printed piece.

10. The printing method according to claim 8, characterized in that:

the quality scores g=ω1×g1+ω2×g2, ω1 and ω2 are weights of the feature and defect, respectively, the quality scores are compared with quality scores conforming to the standard, and the print quality is determined based on the result of the comparison.