Ultrasonic bag sealing device and method

Abstract

This invention discloses an ultrasonic sealing device and method for PE bags, including a production line conveyor belt, a support frame, a telescopic adjustment module, and an ultrasonic transmitting module. A photoelectric switch sensor and a binocular camera are mounted on the upper part of the support frame. The ultrasonic sealing device is controlled by an ultrasonic sealing PE bag information processing system. The ultrasonic sealing subsystem includes a photoelectric switch detection module, an ultrasonic transmitting frequency modulation module, an ultrasonic welding control module, and a pressure driving module. A visual inspection subsystem receives image data captured by the binocular camera. This invention fills the gap in the technology of combining ultrasonic sealing machines with visual recognition cameras, enabling efficient and high-quality PE bag sealing. It can efficiently adjust the ultrasonic frequency, perform negative feedback pressure for high-strength welding, and visually inspect the sealing quality, ensuring that the seal has high strength, excellent integrity, good uniformity, and high sealing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of packaging technology, and in particular relates to an ultrasonic sealing device and a method for sealing PE bags. Background Technology

[0002] With the increasing efforts in rural revitalization, the development of new rural areas and animal husbandry is rapid, leading to a surge in demand for feed. Feed is typically packaged and stored in PE bags or PE bags encased in woven bags. These PE bags are sealed using either stitching or heat-sealing, as seen in technologies such as "202011055130.7 An Automatic Sealing Device for Feed Packaging Bags" and "201922189543.3 An Automatic Cutting and Sealing Machine for Feed Packaging Bags." However, these methods rely on manual control or manual handling of the feed bags, which is time-consuming and labor-intensive. Stitching is slow, and heat-sealing, lacking a monitoring mechanism and relying on heat, can result in uneven bonding. Therefore, existing feed packaging technologies suffer from poor sealing, insecure sealing leading to low sealing efficiency, leakage, and misalignment. Furthermore, during transportation, bumps and pressure can cause tearing and leakage. Summary of the Invention

[0003] This invention provides an ultrasonic sealing device and method for PE bags, which solves the above problems.

[0004] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0005] The present invention provides an ultrasonic sealing device for PE bags, comprising a production line conveyor belt, brackets symmetrically installed on both sides of the production line conveyor belt, telescopic adjustment modules installed on opposite sides of the two brackets, and an ultrasonic transmitting module installed on a sealing robotic arm at the end of a pressure drive module; a photoelectric switch sensor is installed on the upper part of the brackets and a binocular camera is installed on the brackets via a binocular camera fixing bracket; the ultrasonic sealing device is controlled by an ultrasonic sealing PE bag information processing system.

[0006] The ultrasonic sealing PE bag information processing system includes an ultrasonic sealing subsystem and a visual inspection subsystem. The ultrasonic sealing subsystem includes a photoelectric switch detection module connected to a photoelectric switch sensor, an ultrasonic emission frequency modulation module connected to an ultrasonic emission module, an ultrasonic welding control module, and a pressure drive module connected to a telescopic adjustment module. The visual inspection subsystem receives image data captured by a binocular camera and includes an image preprocessing module and a welding area image segmentation module.

[0007] Furthermore, the photoelectric switch sensor detects whether a PE bag is placed between the opposite sides of the ultrasonic transmitting modules mounted on the two brackets.

[0008] Furthermore, the ultrasonic transmitting frequency modulation module is used to adjust the ultrasonic frequency of the ultrasonic transmitting module, and to weld PE bags of different thicknesses and widths using ultrasonic waves of different frequencies.

[0009] Furthermore, the telescopic adjustment module adopts any one of hydraulic cylinder, pneumatic cylinder, electric cylinder, or slide table; the pressure drive module is a drive controller, and a pressure sensor is provided at the end of the telescopic adjustment module.

[0010] Furthermore, the support is a lifting type, including manual lifting or automatic lifting.

[0011] An ultrasonic sealing method for PE bags, using the aforementioned ultrasonic sealing device for PE bags, includes the following steps:

[0012] S1. Preparation stage: The PE bags filled with feed are transported by the production line conveyor belt to the ultrasonic sealing area located between two supports. The supports are manually or automatically adjusted according to the sealing height of the PE bags so that the ultrasonic transmitting module is exactly facing the sealing position. The photoelectric switch sensor is turned on and the photoelectric switch detection module detects whether there are PE bags.

[0013] If so, pause the conveyor belt operation on the production line and activate the ultrasonic transmitter frequency modulation module. Adjust the ultrasonic frequency output by the ultrasonic transmitter module according to the thickness and density of the PE bag; find the corresponding frequency range from the system based on the thickness and density of the PE bag. m ,f n ], and determine the frequency f at this time. i Does it fall within this range? If f m ≤f i ≤f n If the frequency is within this range, then this frequency can be used; otherwise, calculate the frequency deviation. The corrected frequency f = f i Welding is performed using ±Δf, and the welding time is denoted as t.

[0014] If not, continue the conveyor belt operation on the production line;

[0015] S2. Ultrasonic Welding: The pressure-driven module controls the telescopic adjustment module to apply pressure to the sealing position of the PE bag, and the pressure sensor calculates the applied pressure F in real time. N =∫2tG(f i )dt, while applying pressure, control the ultrasonic transmitting module to output ultrasonic waves of the corresponding frequency, record the application time as T, and determine whether the time satisfies 0.65t<T≤0.85t;

[0016] If so, the reverse stroke cancels the pressure of the telescopic adjustment module, the sealing is completed, and it enters the vision inspection subsystem to detect the ultrasonic sealing quality;

[0017] If not, then perform time correction. Use the corrected time T+ΔT and calculate the new pressure application time;

[0018] S3. Visual Inspection Subsystem for Ultrasonic Sealing Quality Inspection: After ultrasonic sealing welding is completed, a binocular camera located on two supports acquires images of the sealed area. The acquired images I(x,y) are pre-processed using a Gaussian function G(x,y,σ) to remove high-frequency noise caused by factors such as lighting conditions. The process is as follows:

[0019]

[0020]

[0021] In the formula, L(x,y,σ) is the scale-space image after convolving the Gaussian function with the original image; G(x,y,σ) is the two-dimensional Gaussian function; This represents the convolution operation; I(x,y) is the original image; σ is the scale space factor; the smaller the value of σ, the less the image is smoothed.

[0022] The preprocessed image is segmented into welding regions using region growing and watershed segmentation algorithms. Region growing begins with a set of seed pixels representing different growth regions. Next, pixels within the vicinity of the seed pixels that meet certain criteria are merged into the growth region represented by the seed pixel, and newly added pixels are used as new seed pixels to continue the merging process until no new pixels meeting the criteria are found. Then, the watershed algorithm is used to refine and fill the edges of the region growth. Finally, a mathematical morphology segmentation method based on topological theory is used to calculate the area S of the welding region from the pixels. i Through the set threshold range [S m ,S n Determine the actual welding area S i Does it meet this range, i.e., S? m ≤S i ≤S n Is it valid?

[0023] If not, calculate the area deviation. The output is sent to the ultrasonic sealing subsystem, where the PE bag is ultrasonically welded again, and the process ends.

[0024] If so, the sealing test is complete, and the PE bag is removed from the production line via the production line conveyor belt.

[0025] The present invention has the following advantages over the prior art:

[0026] This technical solution combines ultrasonic welding with visual recognition and detection technology, filling the gap in the technology of combining ultrasonic sealing machines with visual recognition cameras. It can complete efficient and high-quality PE bag sealing. Compared with existing heat-pressing bonding, sewing, and ordinary ultrasonic sealing, it can efficiently adjust the ultrasonic frequency, perform negative feedback pressure super welding function, and visually inspect the sealing quality. This ensures that the sealing has high strength, excellent integrity, good uniformity, and high sealing efficiency, greatly improving the level and efficiency of automated sealing of feed PE bags.

[0027] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of an ultrasonic sealing device for PE bags according to the present invention;

[0030] Figure 2 for Figure 1 Module connection framework diagram of the ultrasonic sealing PE bag information processing system;

[0031] Figure 3 The flowchart shows steps S1 and S2 of the ultrasonic sealing method for PE bags.

[0032] Figure 4 A flowchart of step S3 of the ultrasonic sealing method for PE bags;

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 1-Binocular camera mounting bracket, 2-Binocular camera, 3-Telescopic adjustment module, 4-Ultrasonic transmitting module, 5-Bracket, 6-Production line conveyor belt, A-Ultrasonic sealing PE bag information processing system. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In the description of this invention, it should be understood that the terms "side", "opposite", "both sides", "end", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0037] Please see Figure 1 As shown, an ultrasonic sealing device for PE bags according to the present invention includes a production line conveyor belt 6, brackets 5 symmetrically installed on both sides of the production line conveyor belt 6, telescopic adjustment modules 3 installed on opposite sides of the two brackets 5, and ultrasonic transmitting modules 4 installed on the sealing robotic arm at the end of the pressure drive module 3; a photoelectric switch sensor is installed on the upper part of the bracket 5 and a binocular camera 2 is installed on the bracket 1 fixed by a binocular camera; the ultrasonic sealing device is controlled by an ultrasonic sealing PE bag information processing system A; in this specific embodiment, the production line conveyor belt 6 is an industrial conveyor belt with a non-slip surface. After the PE bag is filled with feed at one end of the production line conveyor belt 6, it is conveyed towards the direction where the ultrasonic sealing device is located, with the exposed seal facing upwards. The sealing direction of the seal is consistent with the arrangement direction of the ultrasonic transmitting modules 4 on the two brackets 5. Figure 1 As shown, in this specific embodiment, the ultrasonic transmitting module 4 is arranged horizontally, and each ultrasonic transmitting module 4 is fixedly connected to the ends of the two telescopic adjustment modules 3 respectively;

[0038] The telescopic adjustment module 3 can be any one of a hydraulic cylinder, pneumatic cylinder, electric cylinder, or slide table. In this specific embodiment, it is driven by an electric cylinder. The ultrasonic transmitting module 4 is installed at the end of the electric cylinder lifting head. The pressure driving module is a drive controller, and a pressure sensor is provided at the end of the telescopic adjustment module 3. After the two ultrasonic transmitting modules 4 are pressed together, the pressure value data of the compression can be obtained through the pressure sensor, and the pressure value data is transmitted to the control system in real time. The photoelectric switch sensor is a grid-type photoelectric switch. The photoelectric switch sensor detects whether a PE bag is placed between the opposite sides of the ultrasonic transmitting modules 4 installed on the two brackets 5.

[0039] like Figure 2As shown, the ultrasonic sealing PE bag information processing system A includes an ultrasonic sealing subsystem and a visual inspection subsystem. The ultrasonic sealing subsystem includes a photoelectric switch detection module connected to a photoelectric switch sensor, an ultrasonic emission frequency modulation module connected to an ultrasonic emission module 4, an ultrasonic welding control module, and a pressure drive module connected to a telescopic adjustment module 3. The visual inspection subsystem receives image data captured by a binocular camera 2 and includes an image preprocessing module and a welding area image segmentation module.

[0040] The ultrasonic emission frequency modulation module is used to adjust the ultrasonic frequency of the ultrasonic emission module 4, enabling the welding of PE bags of different thicknesses and widths using ultrasonic waves of different frequencies. It can weld PE bags using ultrasonic waves of corresponding frequencies and record the welding time t. The pressure drive module applies pressure to the sealing position of the PE bag, and the magnitude of the applied pressure F is determined by the ultrasonic frequency and the welding time. N The time T is used to detect the ultrasonic sealing quality through a machine vision system. A Gaussian filtering algorithm is used to smooth the image and remove high-frequency noise. The acquired image is then segmented into welding areas using a watershed algorithm and a region growing algorithm. The area of ​​the ultrasonic welding area is calculated based on the pixels, and the calculated area S is used as the basis for further analysis. n To determine the quality of ultrasonically welded PE bags.

[0041] Among them, bracket 5 is a lifting type, including manual lifting or automatic lifting; for manual lifting, a crank lifting action can be performed by using a screw and slider; for automatic lifting, a screw mechanism, hydraulic cylinder, pneumatic cylinder or electric cylinder mechanism can be used to achieve the height lifting action.

[0042] like Figure 3-4 As shown, an ultrasonic sealing method for PE bags, implemented using the aforementioned ultrasonic sealing device for PE bags, includes the following steps:

[0043] S1. Preparation stage: The PE bags filled with feed are transported by the production line conveyor belt 6 to the ultrasonic sealing area located between the two supports 5. The supports 5 are manually or automatically adjusted according to the sealing height of the PE bags so that the ultrasonic transmitting module 4 is exactly facing the sealing position. The photoelectric switch sensor is turned on and the photoelectric switch detection module detects whether there are PE bags.

[0044] If so, pause the transmission operation of conveyor belt 6 on the production line and turn on the ultrasonic transmitting frequency modulation module. Adjust the ultrasonic frequency output by ultrasonic transmitting module 4 according to the thickness and density of the PE bag; find the corresponding frequency range from the system according to the thickness and density of the PE bag [f]. m ,f n ], and determine the frequency f at this time. i Does it fall within this range? If f m ≤fi ≤f n If the frequency is within this range, then this frequency can be used; otherwise, calculate the frequency deviation. The corrected frequency f = f i Welding is performed using ±Δf, and the welding time is denoted as t.

[0045] If not, continue the transmission operation of conveyor belt 6 on the production line;

[0046] S2. Ultrasonic welding: The pressure drive module controls the telescopic adjustment module 3 to apply pressure to the sealing position of the PE bag, and the pressure sensor calculates the applied pressure F in real time. N =∫2tG(f i )dt, while applying pressure, control the ultrasonic transmitting module 4 to output ultrasonic waves of the corresponding frequency, record the application time as T, and determine whether the time satisfies 0.65t<T≤0.85t;

[0047] If so, the pressure of the telescopic adjustment module 3 is released in reverse, the sealing is completed, and the system enters the visual inspection subsystem to detect the ultrasonic sealing quality.

[0048] If not, then perform time correction. Use the corrected time T+ΔT and calculate the new pressure application time;

[0049] S3. Visual Inspection Subsystem for Ultrasonic Sealing Quality Inspection: After ultrasonic sealing welding is completed, a binocular camera 2 located on the two supports 5 acquires images of the sealed area. The acquired images I(x,y) are pre-processed by filtering with a Gaussian function G(x,y,σ) to remove high-frequency noise caused by factors such as lighting conditions. The process is as follows:

[0050]

[0051]

[0052] In the formula, L(x,y,σ) is the scale-space image after convolving the Gaussian function with the original image; G(x,y,σ) is the two-dimensional Gaussian function; This represents the convolution operation; I(x,y) is the original image; σ is the scale space factor; the smaller the value of σ, the less the image is smoothed.

[0053] The preprocessed image is segmented into welding regions using region growing and watershed segmentation algorithms. Region growing begins with a set of seed pixels representing different growth regions. Next, pixels within the vicinity of the seed pixels that meet certain criteria are merged into the growth region represented by the seed pixel, and newly added pixels are used as new seed pixels to continue the merging process until no new pixels meeting the criteria are found. Then, the watershed algorithm is used to refine and fill the edges of the region growth. Finally, a mathematical morphology segmentation method based on topological theory is used to calculate the area S of the welding region from the pixels. i Through the set threshold range [S m ,S n Determine the actual welding area S i Does it meet this range, i.e., S? m ≤S i ≤S n Is it valid?

[0054] If not, calculate the area deviation. The output is sent to the ultrasonic sealing subsystem, where the PE bag is ultrasonically welded again, and the process ends.

[0055] If so, the sealing test is complete, and the PE bag is removed from the production line via conveyor belt 6.

[0056] The basic idea of ​​the above algorithm is to treat the image as a topographical feature in geodesy. The gray value of each pixel in the image represents the altitude of that point. Each local minimum and its image region is called a catchment basin, and the boundary of the catchment basin forms a watershed. The watershed has a good response to weak edges. Noise in the image and subtle gray value changes on the surface of objects may cause over-segmentation, but this also ensures that closed and continuous edges are obtained.

[0057] This technical solution fills the gap in the field of combining vision technology with ultrasonic sealing machine cameras to achieve efficient and high-quality PE bag sealing. Compared with existing sealing machines, it has three major advantages: adjustable ultrasonic frequency, negative feedback pressure for super-strong welding, and visual inspection of sealing quality.

[0058] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. An ultrasonic sealing device for PE bags, characterized in that, The device includes a production line conveyor belt (6), brackets (5) symmetrically installed on both sides of the production line conveyor belt (6), telescopic adjustment modules (3) installed on opposite sides of the two brackets (5), and an ultrasonic transmitting module (4) installed on the sealing robot arm at the end of the telescopic adjustment module (3); a photoelectric switch sensor is installed on the upper part of the bracket (5), and a binocular camera (2) is installed on the binocular camera fixing bracket (1); the ultrasonic sealing device is controlled by an ultrasonic sealing PE bag information processing system (A); The ultrasonic sealing PE bag information processing system (A) includes an ultrasonic sealing subsystem and a visual inspection subsystem; the ultrasonic sealing subsystem includes a photoelectric switch detection module connected to a photoelectric switch sensor, an ultrasonic emission frequency modulation module connected to an ultrasonic emission module (4), an ultrasonic welding control module, and a pressure drive module connected to a telescopic adjustment module (3); the visual inspection subsystem receives image data captured by a binocular camera (2), including an image preprocessing module and a welding area image segmentation module.

2. The ultrasonic sealing device for PE bags according to claim 1, characterized in that, The photoelectric switch sensor detects whether a PE bag is placed between the opposite sides of the ultrasonic transmitting module (4) installed on the two brackets (5).

3. The ultrasonic sealing device for PE bags according to claim 1, characterized in that, The ultrasonic transmitting frequency modulation module is used to adjust the ultrasonic frequency of the ultrasonic transmitting module (4) and to weld PE bags of different thicknesses and widths using ultrasonic waves of different frequencies.

4. The ultrasonic sealing device for PE bags according to claim 1, characterized in that, The telescopic adjustment module (3) is any one of a hydraulic cylinder, pneumatic cylinder, electric cylinder, or slide table; the pressure drive module is a drive controller, and a pressure sensor is provided at the end of the telescopic adjustment module (3).

5. The ultrasonic sealing device for PE bags according to claim 1, characterized in that, The bracket (5) is a lifting type, including manual lifting or automatic lifting.

6. An ultrasonic sealing method for PE bags, characterized in that, The ultrasonic sealing device for PE bags as described in any one of claims 1-5 is used, comprising the following steps: S1. Preparation stage: The PE bags filled with feed are transported by the production line conveyor belt (6) to the ultrasonic sealing area between the two supports (5). According to the sealing height of the PE bag, the supports (5) are manually or automatically adjusted so that the ultrasonic transmitting module (4) is directly facing the sealing position. The photoelectric switch sensor is turned on and the photoelectric switch detection module detects whether there is a PE bag. If so, pause the conveyor belt (6) of the production line and turn on the ultrasonic transmission frequency modulation module. Adjust the ultrasonic frequency output by the ultrasonic transmission module (4) according to the thickness and density of the PE bag; find the corresponding frequency range from the system according to the thickness and density of the PE bag. m ,f n ], and determine the frequency f at this time. i Does it fall within this range? If f m≤ f i≤ f n If the frequency is within this range, then this frequency can be used; otherwise, calculate the frequency deviation. The corrected frequency f = f i Welding is performed using ±Δf, and the welding time is denoted as t. If not, continue the conveyor belt (6) transmission operation on the production line; S2, Ultrasonic Welding: The pressure drive module controls the telescopic adjustment module (3) to apply pressure to the sealing position of the PE bag, and the pressure F is calculated in real time by the pressure sensor. N =∫2tG(f i While applying pressure, the ultrasonic transmitting module (4) is controlled to output ultrasonic waves of the corresponding frequency, and the application time is recorded as T. It is then determined whether the time requirement of 0.65t is met. <T≤0.85t; If so, the pressure of the telescopic adjustment module (3) is canceled in reverse, the sealing is completed, and it enters the visual inspection subsystem to detect the ultrasonic sealing quality; If not, then perform time correction. Use the corrected time T+ΔT and calculate the new pressure application time; S3. Visual inspection subsystem for detecting ultrasonic sealing quality: After ultrasonic sealing welding is completed, the binocular camera (2) located on the two supports (5) acquires the image after sealing. The acquired image I(x,y) is preprocessed by filtering with Gaussian function G(x,y,σ) to remove high-frequency noise caused by lighting conditions. The process is as follows: In the formula, L(x,y,σ) is the scale-space image after convolving the Gaussian function with the original image; G(x,y,σ) is the two-dimensional Gaussian function; This represents the convolution operation; I(x,y) is the original image; σ is the scale space factor; the smaller the value of σ, the less the image is smoothed. The preprocessed image is segmented into welding regions. The region growing algorithm and the water segmentation algorithm are used to segment the welding regions. The region growing starts with a set of seed pixels representing different growth regions. Then, the pixels in the neighborhood of the seed pixels that meet the conditions are merged into the growth region represented by the seed pixels. The newly added pixels are used as new seed pixels to continue the merging process until no new pixels that meet the conditions can be found. Then, the watershed algorithm is used to refine and fill the edge of the region growth, and a mathematical morphology segmentation method based on topological theory is used to calculate the area S of the welding region from the pixels. i Through the set threshold range [S m ,S n Determine the actual welding area S i Does it meet this range, i.e., S? m ≤S i ≤S n Is it valid? If not, calculate the area deviation. The output is sent to the ultrasonic sealing subsystem, where the PE bag is ultrasonically welded again, and the process ends. If so, the sealing test is completed, and the PE bag is removed from the production line via the production line conveyor belt (6).

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