Hot melt adhesive foaming machine and hot melt adhesive foaming method

Abstract

The present application relates to the field of foaming machine, especially to a hot melt adhesive foaming machine, comprising a detection device, an image processor, a controller, a fluid pipeline provided with a first electric control adjusting valve, a gas pipeline provided with a second electric control adjusting valve, a mixing cylinder provided with stirring blades and a stirring servo motor; the detection device comprises a transparent panel, a light transmission bottom plate, a fluid pump, an image camera and a light source, the transparent panel and the light transmission bottom plate are arranged in parallel and spaced apart, the periphery of the transparent bottom plate is closed with the light transmission bottom plate, and detection inlet pipes and detection outlet pipes are arranged at opposite ends, so that a material passing gap for accommodating the foaming hot melt adhesive is formed between the transparent panel and the light transmission bottom plate, the fluid pump is arranged on the detection outlet pipe, the light source illuminates the light transmission bottom plate, the image camera shoots a detection image towards the transparent panel, the image processor is signal connected with the image camera, the controller is signal connected with the image processor, and the controller is connected with and controls the first electric control adjusting valve, the second electric control adjusting valve and the stirring servo motor.

Description

Technical Field

[0001] This invention relates to the field of foaming machines, and particularly to a hot melt adhesive foaming machine and a hot melt adhesive foaming method. Background Technology

[0002] In real life, foamed products are mainly obtained through chemical or physical foaming methods. A foaming agent is added to the raw materials, and foaming occurs simultaneously with the reaction to obtain the product. However, the foaming ratio of chemical or physical foaming is limited. For example, the degree of foaming in the chemical foaming method of hot melt adhesives is greatly related to the amount of foaming agent added. If different foaming rates are required, the amount of foaming agent needs to be controlled, and errors in dosage can lead to unstable foaming rates. Physical foaming methods typically use mechanical stirring, which has low foaming efficiency and is even more difficult to control the foaming rate. Therefore, it is necessary to design a foaming machine that can combine the addition of gas to the hot melt adhesive fluid with mechanical stirring and then detect the foaming rate of the combined foamed hot melt adhesive. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a hot melt adhesive foaming machine that can calculate and detect the foaming rate of hot melt adhesive.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a hot melt adhesive foaming machine, comprising a fluid pipeline, a gas pipeline, a mixing cylinder, and a discharge pipeline, wherein the fluid pipeline is connected to the mixing cylinder and supplies hot melt adhesive fluid, the gas pipeline is connected to the mixing cylinder and supplies gas, and the mixing cylinder supplies foamed hot melt adhesive through the discharge pipeline; it also includes a detection device, an image processor, and a controller; the fluid pipeline is equipped with a first electrically controlled regulating valve, the gas pipeline is equipped with a second electrically controlled regulating valve, and the mixing cylinder is equipped with stirring blades and a stirring servo motor for driving the stirring blades to rotate;

[0005] The detection device includes a transparent panel, a light-transmitting base plate, a fluid pump, an image camera, and a light source. The transparent panel and the light-transmitting base plate are arranged parallel to each other and spaced apart. The outer periphery of the transparent panel and the light-transmitting base plate is closed, and detection inlet pipe and detection outlet pipe are provided at opposite ends, so that a material passage gap is formed between the transparent panel and the light-transmitting base plate to accommodate the passage of foamed hot melt adhesive. The detection inlet pipe and the detection outlet pipe are respectively connected to the front and rear ends of the discharge pipeline along the conveying direction. The fluid pump is located on the detection outlet pipe. The light source faces and illuminates the light-transmitting base plate. The image camera faces the transparent panel to capture detection images. The image processor is signal-connected to the image camera to receive and process the detection images. The controller is signal-connected to the image processor and is connected to and controls the first electrically controlled regulating valve, the second electrically controlled regulating valve, and the stirring servo motor.

[0006] Furthermore, the detection inlet pipe is connected to the material passage gap via a material distribution plate. The material distribution plate includes a connector and a dispersing head. The dispersing head has a structure with both sides expanding outwards. The connector is connected to the detection inlet pipe. The dispersing head has several partitions inside, and the partitions are spaced apart to form several channels facing the material passage gap.

[0007] Furthermore, the transparent panel and the light-transmitting base plate are set parallel to each other at a distance of 0.5 to 1 mm.

[0008] Furthermore, the detection outlet pipe is connected to the material passage gap by means of a material gathering head.

[0009] Furthermore, the light-transmitting base plate is a light-diffusing plate, and the light source consists of several lamp beads arranged at intervals. The lamp beads are arranged parallel to the light-transmitting base plate at intervals and emit light upwards toward the light-transmitting base plate.

[0010] Furthermore, it also includes an infrared heating tube, a first temperature detector, and a second temperature detector. The infrared heating tube is mounted above the transparent panel. The first temperature detector is located on one side of the infrared heating tube to detect the temperature of the infrared heating tube. The second temperature detector is located on the discharge pipe to detect the temperature inside the discharge pipe.

[0011] Furthermore, it also includes a receiving trough, which is connected to the mixing cylinder via a fluid pipeline.

[0012] Furthermore, it also includes a return cylinder, the discharge pipe is connected to the return cylinder, and the return cylinder is provided with a return pipe connected to the receiving trough. The return cylinder is connected to a negative pressure vacuum pump, which is used to extract gas from the return cylinder.

[0013] Furthermore, the discharge pipe is equipped with a switch valve for controlling the return cylinder to receive the foamed hot melt adhesive, and the discharge pipe is equipped with a dispensing valve for controlling the output of the foamed hot melt adhesive.

[0014] A method for foaming hot melt adhesive, including

[0015] A1. Hot melt adhesive is fed into the mixing cylinder through a fluid pipeline, and gas is fed into the mixing cylinder through a gas pipeline. The stirring blades of the mixing cylinder disperse the gas and mix it into the hot melt adhesive, so that the gas is distributed in the hot melt adhesive in the form of bubbles. The foamed hot melt adhesive is sent out through the discharge pipeline.

[0016] A2. A portion of the foamed hot melt adhesive in the discharge pipe enters the material passage gap through the detection feed pipe. The foamed hot melt adhesive fills the material passage gap and is spread into a thin layer. Then it is sent out by the detection discharge pipe and returned to the discharge pipe.

[0017] A3. The light source illuminates the transparent substrate, which is in a thin layer of foamed hot melt adhesive. The image camera is pointed at the transparent panel to capture the detection image and sends the detection image to the image processor.

[0018] A4. Preset the bubble image area ratio range value B and the standard deviation range value C in the image processor; the image processor calculates the area of ​​the detection image through the image processing algorithm to obtain the detection image area S1, identifies and extracts the bubble images in the detection image, calculates the area of ​​each bubble image respectively, and adds the areas of each bubble image to obtain the total bubble image area S2.

[0019] Divide the total bubble area S2 by the detected image area S1 to obtain the detected bubble area ratio value B1. Compare the detected bubble area ratio value B1 with the preset bubble area ratio range value B. If the detected bubble area ratio value B1 is less than the preset bubble area ratio range value B, the controller will reduce the opening of the first electrically controlled regulating valve or increase the opening of the second electrically controlled regulating valve. If the detected bubble area ratio value B1 is within the preset bubble area ratio range value B, the opening of the first electrically controlled regulating valve and the second electrically controlled regulating valve will be maintained. If the detected bubble area ratio value B1 is greater than the preset bubble area ratio range value B, the opening of the first electrically controlled regulating valve will be increased or the opening of the second electrically controlled regulating valve will be decreased.

[0020] The standard deviation of the area of ​​each bubble image is calculated to obtain the detection standard deviation σ. If the detection standard deviation σ is greater than the preset standard deviation range value C, the speed of the stirring servo motor is increased; if the detection standard deviation σ is within the preset standard deviation range value C, the speed of the stirring servo motor is maintained; if the detection standard deviation σ is less than the preset standard deviation range value C, the speed of the stirring servo motor is decreased.

[0021] As can be seen from the above description of the present invention, compared with the prior art, the hot melt adhesive foaming machine and hot melt adhesive foaming method provided by the present invention are equipped with a detection device to detect the foaming rate of the foamed hot melt adhesive after the mixed gas has been stirred. By setting a transparent panel and a light-transmitting base plate at parallel intervals, a small portion of the foamed hot melt adhesive can enter the material gap through the detection inlet pipe. Since the interval of the material gap is controlled between 0.5 and 1 mm, the foamed hot melt adhesive is squeezed and flattened into a thin layer in the material gap, and the number and distribution of bubbles are visible.

[0022] An image camera is set up to capture images of the foamed hot melt adhesive in the material feeding gap, and the images are transmitted to an image processor. The image processor identifies and extracts the bubbles in the images and calculates the area of ​​each image.

[0023] By connecting the controller to the image processor, the controller can adjust the working status of the first electrically controlled regulating valve, the second electrically controlled regulating valve, and the stirring servo motor according to the calculation results of the image processor, thereby adjusting the output of foamed hot melt adhesive with a stable foaming rate.

[0024] The purpose of setting up a light source to illuminate the light-transmitting substrate is to make the images captured by the image camera clearer when they are being inspected.

[0025] The purpose of setting up the infrared heating tube is to continuously heat the transparent panel, keeping it at a temperature that prevents the hot melt foam from solidifying and avoids residual hot melt foam from solidifying in the material passage gap, thus affecting the conveying effect. A first temperature detector and a second temperature detector are also set up to monitor the temperature of the infrared heating tube and the discharge pipe in real time. When the temperature detected by the second temperature detector on the discharge pipe is lower than the temperature detected by the first temperature detector on the infrared heating tube, the temperature of the infrared heating tube can be adjusted to raise the temperature of the discharge pipe, preventing the foaming performance from being affected by a drop in temperature.

[0026] The purpose of setting up a return cylinder is to receive hot melt adhesive that has not reached the required foaming rate, and to use a negative pressure vacuum pump to remove the air bubbles. The hot melt adhesive after the air bubbles are removed can then travel along the return pipeline to the receiving tank and enter the mixing cylinder along the fluid pipeline to continue mixing with the unfoamed hot melt adhesive to form new hot melt adhesive, thus avoiding waste. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a hot melt adhesive foaming machine according to the present invention.

[0028] Figure 2 This is a schematic diagram of a half-section of the detection device of the present invention.

[0029] Figure 3 This is a top-view half-section structural diagram of the detection device of the present invention.

[0030] Figure 4 This is a schematic diagram of the detection process of the detection device of the present invention.

[0031] The corresponding labels in the diagram are as follows: 1. Fluid pipeline, 11. Receiving trough, 12. Mixing cylinder, 121. Stirring blade, 2. Gas pipeline, 3. Discharge pipeline, 31. Discharge valve, 32. Return cylinder, 321. Switch valve, 322. Negative pressure vacuum pump, 323. Return pipeline, 4. Detection device, 41. Transparent panel, 42. Light-transmitting base plate, 43. Fluid pump, 44. Image camera, 45. Light source, 46. Material passage gap, 47. Detection inlet pipe, 471. Distributing plate, 472. Connector, 473. Dispersing head, 474. Baffle, 48. Detection outlet pipe, 481. Aggregating head, 5. Image processor, 6. First electrically controlled regulating valve, 61. Second electrically controlled regulating valve, 62. Stirring servo motor, 7. Infrared heating tube, 71. First temperature detector, 72. Second temperature detector. Detailed Implementation

[0032] The present invention will be further described below through specific embodiments.

[0033] Reference Figures 1 to 4 The hot melt adhesive foaming machine shown includes a fluid pipeline 1, a gas pipeline 2, a discharge pipeline 3, a detection device 4, and an image processor 5.

[0034] The receiving tank 11 is connected to the mixing cylinder 12 through the fluid pipeline 1 and feeds hot melt adhesive fluid into the mixing cylinder 12. The receiving tank 11 has a heating function to heat the hot melt adhesive so that it always remains in a molten fluid state. The gas pipeline 2 is connected to the mixing cylinder 12 and feeds in gas. The mixing cylinder 12 sends out foamed hot melt adhesive through the dispensing valve via the dispensing pipeline 3. The fluid pipeline 1 is equipped with a first electrically controlled regulating valve 6, which regulates the flow of hot melt adhesive fluid from the receiving trough 11 into the mixing cylinder 12. The gas pipeline 2 is equipped with a second electrically controlled regulating valve 61, which controls the flow of gas into the mixing cylinder 12. The mixing cylinder 12 is equipped with stirring blades 121, which are used to mix the gas with the hot melt adhesive fluid to form foamed hot melt adhesive. The stirring blades 121 are equipped with a stirring servo motor 62 that drives the stirring blades 121 to rotate, and the stirring intensity of the stirring blades 121 is controlled by adjusting the speed of the stirring servo motor 62.

[0035] The detection device 4 includes a transparent panel 41, a light-transmitting base plate 42, a fluid pump 43, an image camera 44, and a light source 45. The transparent panel 41 and the light-transmitting base plate 42 are arranged parallel to each other with a spacing of 0.5 to 1 mm. The outer periphery of the transparent panel 41 and the light-transmitting base plate 42 is closed, and a detection inlet pipe 47 and a detection outlet pipe 48 are provided at opposite ends, so that a material passage gap 46 is formed between the transparent panel 41 and the light-transmitting base plate 42 to accommodate the passage of foamed hot melt adhesive. The detection inlet pipe 47 and the detection outlet pipe 48 are respectively connected to the discharge pipe 3 along the conveying direction. At both ends of the device, the fluid pump 43 is installed on the detection outlet pipe 48. The fluid pump 43 is used to control the foamed hot melt adhesive in the discharge pipe 3 to enter the material passage gap 46. The light source 45 faces and illuminates the light-transmitting base plate 42. The image camera 44 faces the transparent panel 41 to capture detection images. The image processor 5 is signal-connected to the image camera 44 and is used to receive and process the detection images. The controller is signal-connected to the image processor 5 and is connected to and controls the first electrically controlled regulating valve 6, the second electrically controlled regulating valve 61, and the stirring servo motor 62.

[0036] The detection inlet pipe 47 is connected to the material passage gap 46 via a material distribution plate 471. The material distribution plate 471 includes a connector 472 and a dispersing head 473. The dispersing head 473 has a structure with both sides expanding outwards. The connector 472 is connected to the detection inlet pipe 47. The dispersing head 473 is provided with several partitions 474. The partitions 474 are spaced apart to form several channels facing the material passage gap 46, allowing the foamed hot melt adhesive to enter the detection inlet pipe 47 through the discharge pipe 3. Because the material distribution plate 471 is provided, the foamed hot melt adhesive can be diverted along the partitions 474 into the material passage gap 46 after entering the dispersing head 473, avoiding the foamed hot melt adhesive from converging into the material passage gap 46, which could easily lead to uneven distribution in the material passage gap 46. The detection outlet pipe 48 is connected to the material passage gap 46 by a material gathering head 481, so that the foamed hot melt adhesive in the material passage gap 46 can be gathered through the material gathering head 481 into the detection outlet pipe 48, and then output from the detection outlet pipe 48 to the discharge pipe 3.

[0037] The transparent panel 41 is made of glass, the light-transmitting base plate 42 is a light-diffusing plate, and the light source 45 consists of several LED beads arranged at intervals. The LED beads are arranged parallel to the light-transmitting base plate 42 vertically and emit light upwards towards the light-transmitting base plate 42, making the image captured by the image camera 44 clearer. The purpose of setting the transparent panel 41 and the light-transmitting base plate 42 at a parallel interval of 0.5 to 1 mm is to allow the foamed hot melt adhesive to form a thin layer, making the number and size distribution of air bubbles in the foamed hot melt adhesive within the material passage gap 46 visible in this thin layer state.

[0038] The system includes an infrared heating element 7, a first temperature detector 71, and a second temperature detector 72. The infrared heating element 7 is mounted above the transparent panel 41. The first temperature detector 71 is located on one side of the infrared heating element 7 to detect its temperature. The second temperature detector 72 is located on the discharge pipe 3 to detect the temperature inside the discharge pipe 3. The purpose of the infrared heating element 7 is to continuously heat the transparent panel 41, maintaining it at a temperature that prevents the hot melt foam from solidifying and avoids residual hot melt foam from solidifying in the material passage gap 46, which would affect the conveying effect. The first temperature detector 71 and the second temperature detector 72 monitor the temperature of the infrared heating element 7 and the discharge pipe 3 in real time. When the temperature detected by the second temperature detector 72 on the discharge pipe 3 is lower than the temperature detected by the first temperature detector 71 on the infrared heating element 7, the temperature of the infrared heating element 7 can be adjusted to raise the temperature of the discharge pipe 3 to match the temperature detected by the first temperature detector 71, thus preventing the foaming performance of the discharge pipe 3 from being affected by a temperature drop.

[0039] The return cylinder 32 is connected to the discharge pipe 3, and the return cylinder 32 is provided with a return pipe 323 connected to the receiving trough 11. The return cylinder 32 is connected to a negative pressure vacuum pump 322, which is used to extract the gas in the return cylinder 32. The function of the return cylinder 32 is to receive the foamed hot melt adhesive that has not reached the required foaming rate, and to extract the air bubbles by the negative pressure vacuum pump 322. The hot melt adhesive after the air bubbles are removed can go along the return pipe 323 to the receiving trough 11, and can also enter the mixing cylinder 12 along the fluid pipe 1 to continue to be mixed with the unfoamed hot melt adhesive to form new hot melt adhesive, thus avoiding waste of hot melt adhesive. The discharge pipeline 3 is equipped with a switch valve 321 that controls the return cylinder 32 to receive the foamed hot melt adhesive. When the switch valve 321 is in the open state, the discharge valve must be in the closed state, and when the discharge valve is in the open state, the switch valve 321 must be in the closed state, so that the discharge state and the return state do not affect each other. The negative pressure vacuum pump 322 works once every period of time, and only works when the foamed hot melt adhesive entering the return cylinder 32 reaches a certain level.

[0040] The working principle of this type of hot melt adhesive foaming machine is as follows:

[0041] The foaming rate of this hot melt adhesive foaming machine is calculated by the ratio of the total bubble image area S2 to the detection image area S1 and the standard deviation of the bubble image area σ. First, the required preset bubble area ratio range value B and the required preset bubble area standard deviation range value C are set in the image processor 5.

[0042] A1. Hot melt adhesive fluid is placed in the receiving tank 11 and enters the mixing cylinder 12 through the fluid pipeline 1. Gas enters the mixing cylinder 12 through the gas pipe. The stirring blades 121 of the mixing cylinder 12 disperse the gas and mix it into the hot melt adhesive, so that the gas is distributed in the hot melt adhesive in the form of bubbles, forming foamed hot melt adhesive and sending it into the discharge pipeline 3.

[0043] A2, start the fluid pump 43, so that the foamed hot melt adhesive is conveyed forward in the discharge pipe 3. A portion of the foamed hot melt adhesive in the discharge pipe 3 passes through the detection feed pipe and the equalizing plate 471 in sequence and enters the material passage gap 46, and fills the material passage gap 46, so that the foamed hot melt adhesive is spread into a thin layer in the material passage gap 46, forming a state in which the number and size distribution of bubbles are visible.

[0044] A3, the light source 45 shines upward on the light-transmitting base plate 42, illuminating the foamed hot melt adhesive in a thin layer state, and the image camera 44 takes a picture of the transparent panel 41 to obtain the detection image and sends the detection image to the image processor 5;

[0045] A4, the image processor 5 identifies and extracts bubbles in the detection image, calculates the area of ​​the extracted bubble image through the image processing algorithm, and calculates the total bubble area S2.

[0046] Divide the total bubble area S2 in the detected image by the area S1 of the detected image to obtain the bubble area ratio B1. Compare the bubble area ratio B1 with the preset bubble area ratio range B.

[0047] If the bubble area ratio B1 is less than the preset bubble area ratio range B, the controller increases the opening of the second electrically controlled regulating valve 61 to increase the amount of gas added, thereby increasing the number of bubbles in the hot melt adhesive fluid. If the bubble area ratio B1 is greater than the preset bubble area ratio range B, the controller decreases the opening of the second electrically controlled regulating valve 61 to reduce the amount of gas added, thereby reducing the number of bubbles in the hot melt adhesive fluid. The detected foamed hot melt adhesive is then returned from the detection outlet pipe 48 to the discharge pipe 3 and mixed with the foamed hot melt adhesive in the discharge pipe 3. The mixture is then sent into the return cylinder 32 by the switch valve 321, and the gas is extracted by the negative pressure vacuum machine and sent back to the receiving tank 11.

[0048] If the bubble area ratio B1 is within the preset bubble area ratio range B, then the opening of the first electric control regulating valve 6 and the second electric control regulating valve 61 is maintained, and the detected foamed hot melt adhesive is returned to the discharge pipe 3 through the detection outlet pipe 48 and mixed with the foamed hot melt adhesive in the discharge pipe 3 and discharged by the discharge valve 31.

[0049] Because the bubble size may vary, the bubble area percentage B1 may fall within the preset bubble area percentage range B, but the number of bubbles may be too high or too low. Therefore, it is necessary to calculate the standard deviation of the bubble area to obtain the detection standard deviation σ and compare it with the preset standard deviation range C. If the detection standard deviation σ is greater than the preset standard deviation range C, it indicates that there are large bubbles, so the stirring servo motor speed 62 is increased to break up the large bubbles. If the detection standard deviation σ is within the preset standard deviation range C, the stirring servo motor speed 62 is maintained. If the detection standard deviation σ is less than the preset standard deviation range C, it indicates that there are fewer bubbles that need to be broken up, so the stirring servo motor speed 62 is decreased.

[0050] A5. Based on the image calculations in step A4, if the detected bubble image area ratio B1 is not within the preset bubble area ratio range B, or the detection standard deviation σ is not within the preset standard deviation range C, the hot melt foamed adhesive is discharged from the discharge pipe 3 through the switch valve 321 and enters the return cylinder 32. The negative pressure vacuum pump of the return cylinder 32 extracts the gas and sends it back to the receiving tank 11, and steps A1 to A4 are repeated until hot melt foamed adhesive that meets all preset values ​​can be output. If the detected bubble image area ratio is within the preset bubble area ratio range and the detection standard deviation is within the preset standard deviation range, the hot melt foamed adhesive is discharged from the discharge pipe 3 through the discharge valve 31.

[0051] The above is only one specific embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing the protection scope of the present invention.

Claims

1. A hot melt adhesive foaming machine, comprising a fluid pipeline, a gas pipeline, a mixing cylinder, and a discharge pipeline, wherein the fluid pipeline is connected to the mixing cylinder and supplies hot melt adhesive fluid, the gas pipeline is connected to the mixing cylinder and supplies gas, and the mixing cylinder supplies foamed hot melt adhesive through the discharge pipeline. Its features are: It also includes a detection device, an image processor, and a controller; The fluid pipeline is equipped with a first electrically controlled regulating valve, the gas pipeline is equipped with a second electrically controlled regulating valve, and the mixing cylinder is equipped with stirring blades and a stirring servo motor that drives the stirring blades to rotate. The detection device includes a transparent panel, a light-transmitting base plate, a fluid pump, an image camera, and a light source. The transparent panel and the light-transmitting base plate are arranged parallel to each other and spaced apart. The outer periphery of the transparent panel and the light-transmitting base plate is closed, and detection inlet pipe and detection outlet pipe are provided at opposite ends, so that a material passage gap is formed between the transparent panel and the light-transmitting base plate to accommodate the passage of foamed hot melt adhesive. The detection inlet pipe and the detection outlet pipe are respectively connected to the front and rear ends of the discharge pipeline along the conveying direction. The fluid pump is located on the detection outlet pipe. The light source faces and illuminates the light-transmitting base plate. The image camera faces the transparent panel to capture detection images. The image processor is signal-connected to the image camera to receive and process the detection images. The controller is signal-connected to the image processor and is connected to and controls the first electrically controlled regulating valve, the second electrically controlled regulating valve, and the stirring servo motor.

2. The hot melt adhesive foaming machine according to claim 1, characterized in that: The detection inlet pipe is connected to the material passage gap via a material distribution plate. The material distribution plate includes a connector and a dispersing head. The dispersing head has a structure with both sides expanding outwards. The connector is connected to the detection inlet pipe. The dispersing head has several partitions inside, and the partitions are spaced apart to form several channels facing the material passage gap.

3. The hot melt adhesive foaming machine according to claim 2, characterized in that: The transparent panel and the light-transmitting base plate are set parallel to each other at a distance of 0.5 to 1 mm.

4. The hot melt adhesive foaming machine according to claim 1, characterized in that: The detection outlet pipe is connected to the material passage gap by a material gathering head.

5. The hot melt adhesive foaming machine according to claim 1, characterized in that: The light-transmitting base plate is a light-diffusing plate, and the light source consists of several LED beads arranged at intervals. The LED beads are arranged parallel to the light-transmitting base plate at intervals and emit light upwards toward the light-transmitting base plate.

6. The hot melt adhesive foaming machine according to claim 1, characterized in that: It also includes an infrared heating tube, a first temperature detector, and a second temperature detector. The infrared heating tube is mounted above the transparent panel. The first temperature detector is located on one side of the infrared heating tube to detect the temperature of the infrared heating tube. The second temperature detector is located on the discharge pipe to detect the temperature inside the discharge pipe.

7. A hot melt adhesive foaming machine according to claim 1, characterized in that: It also includes a receiving trough, which is connected to the mixing cylinder via a fluid pipeline.

8. The hot melt adhesive foaming machine according to claim 7, characterized in that: It also includes a return cylinder, the discharge pipe is connected to the return cylinder, and the return cylinder is provided with a return pipe connected to the receiving trough. The return cylinder is connected to a negative pressure vacuum pump, which is used to extract the gas in the return cylinder.

9. A hot melt adhesive foaming machine according to claim 8, characterized in that: The discharge pipe is equipped with a switch valve that controls the return cylinder to receive the foamed hot melt adhesive, and the discharge pipe is equipped with a dispensing valve that controls the output of the foamed hot melt adhesive.

10. A method for foaming hot melt adhesive, comprising: A1. Hot melt adhesive is fed into the mixing cylinder through a fluid pipeline, and gas is fed into the mixing cylinder through a gas pipeline. The stirring blades of the mixing cylinder disperse the gas and mix it into the hot melt adhesive, so that the gas is distributed in the hot melt adhesive in the form of bubbles. The foamed hot melt adhesive is sent out through the discharge pipeline. A2. A portion of the foamed hot melt adhesive in the discharge pipe enters the material passage gap through the detection feed pipe. The foamed hot melt adhesive fills the material passage gap and is spread into a thin layer. Then it is sent out by the detection discharge pipe and returned to the discharge pipe. A3. The light source illuminates the transparent substrate, which is in a thin layer of foamed hot melt adhesive. The image camera is pointed at the transparent panel to capture the detection image and sends the detection image to the image processor. A4. Preset the bubble image area ratio range value B and the standard deviation range value C within the image processor; The image processor calculates the area of ​​the detected image using an image processing algorithm to obtain the area S1 of the detected image. It identifies and extracts the bubble images in the detected image, calculates the area of ​​each bubble image separately, and adds the areas of each bubble image to obtain the total area S2 of the bubble image. Divide the total bubble area S2 by the detected image area S1 to obtain the detected bubble area ratio value B1. Compare the detected bubble area ratio value B1 with the preset bubble area ratio range value B. If the detected bubble area ratio value B1 is less than the preset bubble area ratio range value B, the controller will reduce the opening of the first electrically controlled regulating valve or increase the opening of the second electrically controlled regulating valve. If the detected bubble area ratio value B1 is within the preset bubble area ratio range value B, the opening of the first electrically controlled regulating valve and the second electrically controlled regulating valve will be maintained. If the detected bubble area ratio value B1 is greater than the preset bubble area ratio range value B, the opening of the first electrically controlled regulating valve will be increased or the opening of the second electrically controlled regulating valve will be decreased. The standard deviation of the area of ​​each bubble image is calculated to obtain the detection standard deviation σ. If the detection standard deviation σ is greater than the preset standard deviation range value C, the speed of the stirring servo motor is increased; if the detection standard deviation σ is within the preset standard deviation range value C, the speed of the stirring servo motor is maintained; if the detection standard deviation σ is less than the preset standard deviation range value C, the speed of the stirring servo motor is decreased.

Images